JP7750486B2 - engine - Google Patents

Description

The present invention relates to an engine.

A reciprocating engine is configured to move a piston through each of the intake, compression, combustion, and exhaust processes, and convert the reciprocating motion of a connecting rod connected to the piston into rotational motion of a crankshaft using a specified link mechanism, thereby outputting rotational power.
Conventionally, the piston is rotatably supported at the tip of the connecting rod, and the reciprocating motion of the piston and the tip of the connecting rod is converted into rotational motion of the base end of the connecting rod, and the rotational motion of the crankshaft is transmitted via a link mechanism consisting of a crank pin and crank arm.

JP 2015-224745 A discloses a rotational conversion structure for piston motion in a reciprocating engine. The structure comprises at least a connecting rod fixed to the piston, a planetary gear mechanism that converts linear motion into rotational motion, and a drive shaft journaled at the center of the planetary gear. The planetary gear mechanism comprises a pair of internal gears, planetary gears that mesh with each internal gear and whose pitch circle diameter is half that of the internal gears, a connecting rod journaled with the connecting rod via a pin and fixed to the planetary gears, and a fixed rod that is fixed to the planetary gears and the drive shaft. The pin is positioned so that its center is always aligned with the axis of the connecting rod. This minimizes side pressure from the piston in the cylinder, reducing friction loss and enabling a smaller, lighter engine, while also reducing vibration and noise.

Japanese Patent Application Laid-Open No. 2015-224745

In conventional crank structures, the large-diameter portion of the connecting rod's base end rotates along a circumference whose radius is the length of the crank arm. As a result, the reciprocating distance of the connecting rod between top dead center and bottom dead center is equal to the diameter of the crank arm. As a result, if the reciprocating distance is increased, i.e., a long stroke is achieved, the crank arm must also be lengthened, resulting in problems such as an increased crankcase size, and therefore there is a risk that the length of the crank arm will be limited at the current engine design stage. On the other hand, if the reciprocating distance is decreased, i.e., a short stroke is achieved, there is a risk that the length of the crank arm and connecting rod, which make up the crank mechanism that converts reciprocating motion into rotational motion, will be limited.

To address the above-mentioned problems, the piston movement rotation conversion structure disclosed in the aforementioned JP 2016-075208 A has a conversion mechanism consisting of an internal gear and a planetary gear mechanism in place of the crank arm, converting the rotational movement of the crank arm in a conventional crank structure into the rotation of a planetary gear that rolls inscribed in the internal gear, causing the piston to move back and forth in a linear manner, and is configured so that the length of the crank arm does not affect the reciprocating movement.
However, with the above rotation conversion structure, there is a risk that the planetary gears inscribed in the internal gear may slip or deviate from the internal gear due to the pressure applied to the piston, making it impossible to convert force correctly. Also, since the rotation return structure requires a large number of parts, the device becomes complicated, and assembly may be time-consuming and costly.

Therefore, the problem that this invention aims to solve is to provide an engine whose bore and stroke can be freely designed without being restricted by the length of the connecting rod or crank arm.

The engine according to claim 1 comprises: a substantially cylindrical piston having piston heads on both left and right end surfaces;
a through hole having a predetermined inner diameter formed in a radial direction of the piston at the center of a peripheral wall portion of the piston;
an internal gear formed along an inner wall of the through hole;
a gear that meshes with the internal gear;
a substantially rod-shaped crank arm having a crank pin at its tip that supports the gear;
a crankshaft fixed to a base end of the crank arm;
a disk-shaped eccentric free rotor having substantially the same diameter as the inner diameter of the through hole, rotatably fitted into the through hole, and journaled together with the gear by the crank pin;
a cylinder case including a cylindrical cylinder into which the piston is inserted, the piston heads connecting opposing combustion chambers to both ends of the cylinder,
When the piston reciprocates left and right in the cylinder,
the gear meshed with the internal gear that reciprocates following the piston rotates in a predetermined direction within the through hole,
The crank arm rotates the crankshaft in a predetermined direction via the crank pin that supports the gear, and
an engine in which the eccentric free rotor rotates within the through hole in a direction opposite to a rotation direction of the crank arm,
a crankcase is provided so as to surround the through-hole that contains at least the crankshaft and the crank arm;
an intake port having an intake port arranged along the axial direction of the crankshaft of the crankcase, and an exhaust port having an exhaust port arranged at a predetermined position on a side wall portion of the cylinder,
a bypass port that communicates the crankcase with the cylinder and has a cylinder-side open end that is located on the opposite side of the combustion chamber from the exhaust port;
The eccentric free rotor is provided with a notch formed by cutting out an arc-shaped portion at a predetermined position on the periphery of the rotor surface,
The intake port and the notch are disposed opposite to each other,
The invention is characterized in that, as the eccentric free rotor rotates, when the intake port and the notch overlap, the intake port is opened, and when the intake port and the peripheral portion overlap, the intake port is closed .

The engine described in claim 2 is the invention described in claim 1, characterized in that the diameter of the piston near the center of the peripheral wall is smaller than the diameter of the piston skirts formed adjacent to the piston head on both left and right end faces.

The engine described in claim 3 is the invention described in claim 1, characterized in that the diameter of the piston near the center of the peripheral wall is larger than the diameter of the piston skirts formed adjacent to the piston head on both left and right end faces, or the diameter gradually increases from the side of the piston skirt opposite the piston head toward the center of the peripheral wall, forming the portion near the center of the peripheral wall into a substantially spherical shape.

The engine according to claim 4 is the engine according to claim 1, wherein the piston skirts formed on both left and right end surfaces and connected to the piston head are cut out on the opposite side to the piston head,
The piston is characterized in that a flat portion having the through hole is formed near the center of the peripheral wall portion.

The engine according to claim 5 further comprises a spark plug having an electrode disposed at a predetermined position in the combustion chamber,
When the piston head mixes air and atomized fuel in a predetermined ratio to form a combustible gas mixture, the combustible gas mixture is compressed in the combustion chamber, and the combustible gas mixture is ignited by a spark generated from the electrode.

The engine according to claim 6 is the engine according to claim 1, further comprising an injection device having a spray nozzle disposed at a predetermined position in the combustion chamber,
When the piston head suddenly compresses the air in the combustion chamber to form high-temperature, high-pressure air, the injector sprays a predetermined fuel in the form of a mist from the spray nozzle, and the fuel is burned by the high-temperature, high-pressure air.

The engine described in claim 7 is a piston including a pair of substantially cylindrical small diameter portions and a substantially cylindrical large diameter portion having a diameter larger than the small diameter portions and sandwiched between the small diameter portions, wherein a piston head and a piston skirt connected to the piston head are formed on an end surface of the small diameter portion opposite the large diameter portions, and a through hole having a predetermined inner diameter is formed in a radial direction in a center of the large diameter portion;
an internal gear formed along an inner wall of the through hole;
a gear that meshes with the internal gear;
a substantially rod-shaped crank arm having a crank pin at its tip for supporting the gear;
a crankshaft fixed to a base end of the crank arm;
a disk-shaped eccentric free rotor having substantially the same diameter as the inner diameter of the through hole, rotatably fitted into the through hole, and journaled together with the gear by the crank pin;
a pair of cylindrical cylinders into which the small diameter portions are inserted, and a cylinder case connected to the cylinders and including a housing into which the large diameter portions are fitted, the cylinder case having a combustion chamber at the end of the cylinder opposite the housing, the piston head facing the combustion chamber;
When the small diameter portion reciprocates within the cylinder,
The large diameter portion reciprocates in response to the small diameter portion, and the gear meshed with the internal gear rotates in a predetermined direction within the through hole,
The crank arm rotates the crankshaft in a predetermined direction via the crank pin that supports the gear, and
The eccentric free rotor is adapted to rotate within the through hole in a direction opposite to the rotation direction of the crank arm.

The engine according to claim 8 is the engine according to claim 7, further comprising a spark plug having an electrode disposed at a predetermined position in the combustion chamber,
When the piston head mixes air and atomized fuel in a predetermined ratio to form a combustible gas mixture, the combustible gas mixture is compressed in the combustion chamber, and the combustible gas mixture is ignited by a spark generated from the electrode.

The engine according to claim 9 is the engine according to claim 8, further comprising an intake port having an intake port for supplying the combustible gas mixture to the combustion chamber, and an exhaust port having an exhaust port for discharging exhaust gas from the combustion chamber after combustion of the combustible gas mixture;
The intake port and the exhaust port are provided at predetermined positions in the combustion chamber.

The engine according to claim 10 is the engine according to claim 8, further comprising an intake port having an intake port for supplying the combustible gas mixture to the combustion chamber, and an exhaust port having an exhaust port for discharging exhaust gas from the combustion chamber after combustion of the combustible gas mixture,
The intake port is provided at a predetermined position of the cylinder, and the exhaust port is provided at a predetermined position of the combustion chamber,
The intake port is provided with a piston reed valve that restricts the flow of the combustible gas mixture toward the inside of the cylinder in one direction.

The engine according to claim 11 is the engine according to claim 7, further comprising an injection device having a spray nozzle disposed at a predetermined position in the combustion chamber,
When the piston head suddenly compresses the air in the combustion chamber to form high-temperature, high-pressure air, the injector sprays a predetermined fuel in the form of a mist from the spray nozzle, and the fuel is burned by the high-temperature, high-pressure air.

The engine according to claim 12 is the engine according to claim 11, further comprising an intake port having an intake port for supplying the air to the combustion chamber, and an exhaust port having an exhaust port for discharging exhaust gas from the combustion chamber after the combustion of the fuel,
The intake port and the exhaust port are provided at predetermined positions in the combustion chamber.

The engine according to claim 13 is the engine according to claim 11, further comprising an intake port having an intake port for supplying the air to the combustion chamber, and an exhaust port having an exhaust port for discharging exhaust gas from the combustion chamber after the combustion of the fuel,
The intake port is provided at a predetermined position of the cylinder, and the exhaust port is provided at a predetermined position of the combustion chamber,
The intake port is provided with a piston reed valve that restricts the air to flow in one direction toward the inside of the cylinder.

In the engine according to the present invention, piston heads are formed on both left and right end surfaces of a substantially cylindrical piston, and a through hole with a predetermined inner diameter is provided at the center of the peripheral wall along the radial direction of the piston. An internal gear is formed in the through hole, and a gear that meshes with the internal gear and a disk-shaped eccentric free rotor having approximately the same diameter as the inner diameter of the through hole are disposed in the through hole, overlapping the gear. Furthermore, a crank arm is provided at its base end with a crank pin that rotatably supports the gear and eccentric free rotor, and the crank arm is provided with a crankshaft at its tip end.
As a result, when the piston reciprocates within the cylinder, the crankshaft can be rotated via a gear that is meshed with an internal gear that is driven by the piston.
In a conventional reciprocating engine, the piston's reciprocating distance between top and bottom dead centers corresponds to the diameter of the circle drawn by the large diameter part of the connecting rod, and is therefore limited to the diameter of the circle drawn by the tip of the crank arm connected to that large diameter part.
On the other hand, when the diameter of the circle defined by the large-diameter portion of the connecting rod, i.e., the piston's reciprocating distance, is applied to the engine of the present invention, it corresponds to the inner diameter of the internal gear. The crank arm of the engine of the present invention is configured to rotate along a circle described by the crank pin, which supports the gear that meshes with the internal gear. Therefore, similar to the crank arm's rotation once per piston reciprocating motion in a conventional reciprocating engine, if the crank arm is configured to rotate once per piston reciprocating motion in the engine of the present invention, the ratio of the inner diameter of the internal gear to the gear's diameter is preferably 2:1.
As a result, if the piston reciprocating distance is kept constant, the length of the crank arm of the present invention can be halved compared to the length of a conventional crank arm.In addition, because the engine of the present invention does not have a connecting rod, it can be significantly lighter, making it easier to achieve high rotation speeds of the crankshaft.
Furthermore, if the length of the crank arm according to the present invention is the same as that of a conventional crank arm, the engine according to the present invention can obtain twice the gain compared to a conventional reciprocating engine, allowing the piston to move farther. As a result, the piston stroke distance can be extended easily to achieve a long stroke. This improves the engine's combustion efficiency, increases low-speed torque, and improves fuel economy.
According to the present invention, an eccentric free rotor is provided that is rotatably fitted into the through hole. The eccentric free rotor is configured to rotate in the opposite direction to the rotation direction of the crank arm when the piston reciprocates. This allows the eccentric free rotor to bear the stress applied to the through hole by the reciprocating motion of the piston, preventing distortion of the through hole.
Furthermore, the eccentric free rotor fitted in the through hole absorbs the impact transmitted from the piston head to the through hole, preventing the gear from slipping on the internal gear and preventing damage to the internal gear or the gear. In addition, since the eccentric free rotor is rotated once in the opposite direction while the gear rotates once along the internal gear, it is preferable that the position of the axis of the eccentric free rotor journaled by the crank pin be the position of the gear axis relative to the internal gear, i.e., a position where the ratio of the minor axis to the major axis is 1:3.
The engine according to the present invention is configured so that the pistons reciprocate linearly within the opposing cylinders. This suppresses the lateral pressure of the pistons when they press against the cylinder inner wall, thereby reducing piston friction loss. As a result, the generation of vibration or noise due to contact between the piston and the cylinder can be suppressed. Furthermore, by adjusting the length of the approximately cylindrical pistons, it is possible to freely design engines ranging from long strokes to short strokes, thereby providing optimal engines, such as engines with improved fuel efficiency, increased low-speed torque, or high output, depending on the application of the engine, such as vehicles, ships, airplanes, pumps, generators, and agricultural equipment.

Furthermore, in the engine according to the present invention, the substantially cylindrical piston has piston heads on both the left and right end faces, meaning that an engine similar to a conventional horizontally opposed two-cylinder engine can be constructed with piston heads on both the left and right ends of the crankshaft, and cylinders with combustion chambers facing the piston heads.
Here, if the electrode of the spark plug is located at a predetermined position in the combustion chamber, an internal combustion engine can be constructed in which a spark is thrown into the combustible gas mixture compressed by the piston head into the combustion chamber, causing it to ignite and explode.If an injection device with a spray nozzle located at a predetermined position in the combustion chamber is provided, an internal combustion engine can be constructed in which fuel is sprayed in a mist from the spray nozzle into the high-temperature, high-pressure air compressed by the piston head into the combustion chamber, causing it to burn.
In addition, in these internal combustion engines, an intake port with an intake port that supplies combustible gas mixture or air to the combustion chamber, and an exhaust port with an exhaust port that exhausts exhaust gas from the combustion chamber are provided, and the positions of the intake port and exhaust port can be set arbitrarily to suit the type of two-stroke engine or four-stroke engine.
In this case, in the case of a four-stroke engine, the intake port and the exhaust port may be provided at predetermined positions in the combustion chamber.
On the other hand, in the case of two-stroke engines, the type of engine varies depending on the location of the intake port. For example, if the intake port is located at a predetermined position on the cylinder and a piston reed valve is provided to restrict airflow into the intake port so that it only flows in one direction toward the cylinder, it constitutes a piston reed valve-type two-stroke engine. Alternatively, if the intake port is located at a predetermined position on the crankcase and a crankcase reed valve is provided in the intake port so that it only flows in one direction toward the crankcase, it constitutes a crankcase reed valve-type two-stroke engine. Furthermore, if the intake port is located at a predetermined position on the crankcase and an eccentric free rotor is provided with an arc-shaped notch formed in the periphery of the rotor surface, and the intake port is positioned opposite the eccentric free rotor, and as the eccentric free rotor rotates, the intake port is opened when it overlaps the notch and closed when it overlaps the periphery, it constitutes a rotary disc valve-type two-stroke engine.
As described above, the engine according to the present invention can be easily modified to have a long or short stroke, and can be freely selected as either a four-stroke or a two-stroke. This allows the stroke length of the engine according to the present invention to be freely designed, and it can be freely designed to meet the performance requirements of the engine, such as improved fuel efficiency or higher output.

1 is an explanatory diagram showing an outline of the configuration of an engine according to a first embodiment; 1 is an explanatory diagram showing an outline of the configuration of a piston provided in an engine according to a first embodiment; 1 is a cross-sectional view taken along the axial direction of a piston, illustrating an outline of the configuration of an engine according to a first embodiment. 3A to 3C are explanatory diagrams showing an example of the operation of a piston of the engine according to the first embodiment. FIG. 4 is a cross-sectional view taken along the axial direction of the piston, illustrating an outline of another configuration of the piston of the engine according to the first embodiment. 1 is an explanatory diagram showing an outline of the configuration of a horizontally opposed four-cylinder engine based on an engine according to a first embodiment; 10A to 10C are explanatory diagrams showing the outline of the configuration of other shapes of the piston of the engine according to the first embodiment. 10A to 10C are explanatory diagrams showing the outline of the configuration of other shapes of the piston of the engine according to the first embodiment. 10A to 10C are explanatory diagrams showing the outline of the configuration of other shapes of the piston of the engine according to the first embodiment. FIG. 10 is a cross-sectional view taken along the axial direction of a piston, illustrating the outline of the configuration of an engine according to a second embodiment. FIG. 10 is a cross-sectional view taken along the axial direction of the piston, illustrating an outline of another configuration of the engine according to the second embodiment. FIG. 10 is a cross-sectional view taken along the axial direction of the piston, illustrating an outline of another configuration of the engine according to the second embodiment. FIG. 12 is an explanatory diagram showing the outline of the configuration of a horizontally opposed four-cylinder engine based on the engine shown in FIG. 11 . FIG. 10 is an explanatory diagram showing the outline of the configuration of a piston of an engine according to a third embodiment. FIG. 10 is a cross-sectional view taken along the axial direction of a piston, illustrating the outline of the configuration of an engine according to a third embodiment. FIG. 10 is an explanatory diagram showing the outline of the configuration of a horizontally opposed four-cylinder engine based on an engine according to a third embodiment. FIG. 10 is a cross-sectional view taken along the axial direction of a piston, illustrating the outline of the configuration of an engine according to a fourth embodiment. FIG. 10 is an explanatory diagram showing the outline of the configuration of a horizontally opposed four-cylinder engine based on an engine according to a fourth embodiment.

An embodiment of an engine according to the present invention will now be described with reference to the accompanying drawings. Figure 1 is an explanatory diagram showing the outline of the configuration of an engine according to this embodiment, and Figure 2 is an explanatory diagram showing the outline of the configuration of a piston provided in the engine according to this embodiment.

As shown in FIG. 1 , the engine 10 has a piston 11 and a cylinder case 20 .
As shown in FIG. 2, the piston 11 is a generally cylindrical body having piston heads 12, 12 on both left and right end surfaces, and a piston skirt 13 is formed on the peripheral wall of the generally cylindrical body so as to be connected to the piston head 12.
A through hole 14 having a predetermined inner diameter is formed in the center of the peripheral wall along the radial direction of the substantially cylindrical body.

3, the through hole 14 has an internal gear 14a. The internal gear 14a is configured by arranging teeth cut along the axial direction of the through hole 14 in parallel along the circumferential direction of the inner wall of the through hole 14.
As shown in FIGS. 1 to 3, a gear 15 and an eccentric free rotor 16 are provided inside the through hole 14 .
The gear 15 has teeth cut along the axial direction and is configured to mesh with the internal gear 14a so as to be able to roll. The ratio of the diameter r of the gear 15 to the inner diameter R of the internal gear 14a is configured to be 1:2.
The eccentric free rotor 16 is formed in a disk shape with a diameter approximately the same as the inner diameter of the through hole 14, and is slidably and rotatably fitted into the through hole 14. The axis of the eccentric free rotor 16 is located at a position that divides the diameter of the eccentric free rotor 16 into four equal parts, with the ratio of the minor axis to the major axis being 1:3.
The gear 15 and the eccentric free rotor 16 are journalled by a crank pin 17 .

The crank arm 18 has a crank pin 17 at its tip end and a crank shaft 19 at its base end.
When the gear 15 makes one revolution along the internal gear 14a, the crank arm 18 rotates the crankshaft 19 one revolution.
Here, the ratio of the diameter r of the gear 15 to the inner diameter R of the internal gear 14a is configured to be 1:2, so that when the piston 11 makes one reciprocating motion, as shown in Figure 4, the gear 15 rotates twice within the internal gear 14a and returns to its initial position at the start of rotation, causing the crankshaft 19 to rotate one revolution via the crank arm 18.
As a result, the reciprocating motion of the piston 11 can be converted into the rotational motion of the crankshaft 19 via the orbital motion of the gear 15 .
In the engine 10 according to this embodiment, the gear 15 supported by the crank pin 17 is configured to rotate in mesh with the internal gear 14a of the through hole 14, but this is not limited to this. A planetary gear consisting of one or more planetary gears may be meshed between the internal gear 14a and the gear 15, allowing the gear ratio of the crank arm 18 and crankshaft 19 to the internal gear 14a to be freely adjusted.

As shown in Figures 3 and 4, the eccentric free rotor 16 is journaled on the crank pin 17 together with the gear 15. While the gear 15 meshes with the internal gear 14a and rolls within the through hole 14, the eccentric free rotor 16 rotates around the axis of the through hole 14 as the gear 15 rolls, i.e., as the crank pin 17 moves, its eccentric axis rotates around the axis of the through hole 14. As shown in Figures 3 and 4, when the direction of rotation of the gear 15 (arrow T), which rotates the crank arm 18, is defined as the forward direction, the direction of rotation of the eccentric free rotor 16 is the reverse direction, indicated by arrow F. Furthermore, because the eccentric free rotor 16 is journaled on the crank pin 17 together with the gear 15 as shown, the axis of the eccentric free rotor is located at a position where the ratio of the minor axis to the major axis is 1:3 when the diameter of the eccentric free rotor is divided into four. By locating the axis of the eccentric free rotor here, the eccentric free rotor can rotate once in the direction of arrow F while the gear rotates twice in the direction of arrow T.

As a result, the eccentric free rotor 16 fitted into the through hole 14 can rotate within the through hole 14 without interfering with the rolling of the gear 15 that accompanies the reciprocating motion of the piston 11, i.e., the rotation of the crank arm 18. By fitting the eccentric free rotor 16 slidably and rotatably into the through hole 14, the eccentric free rotor 16 can absorb stresses and other forces exerted on the through hole 14 by the reciprocating motion of the piston 11, thereby preventing distortion of the through hole 14 and the internal gear 14a formed along the inner wall of the through hole 14. This prevents the gear 15 from slipping on the internal gear 14a or chipping of teeth.

As shown in Figures 1 to 4, the cylinder case 20 has a cylindrical cylinder 20a. Two combustion chambers 21, 21 of a predetermined shape are formed adjacent to each other on both end faces of the cylinder. The combustion chamber 21 has a spark plug 22, an intake port 23, and an exhaust port 24 formed at predetermined positions.

The spark plug 22 is configured to be energized and ignite to produce a spark when a combustible gas mixture formed by mixing fuel sprayed from a carburetor or injector with air in a predetermined ratio is compressed by the piston 11 in the combustion chamber 21. When the spark causes the combustible gas mixture to explode and burn in the combustion chamber, pressure is applied to the piston head 12, causing the piston 11 to move in the cylinder 20.
The above-mentioned flammable gas mixture is formed by spraying gasoline or alcohol into the air, but is not limited to this and may also be an internal combustion engine that explodes or burns flammable gas extracted from natural gas, hydrogen gas, biomass, etc.

Alternatively, instead of a spark plug, an injection device (not shown) that sprays liquid fuel in a mist may be provided, and a spray port communicating with the injection device may be provided in the combustion chamber 21. In this case, a diesel engine can be constructed in which fuel such as diesel oil is sprayed into high-temperature, high-pressure air compressed by the piston head 12 and burned.

The intake port has an intake port 23 configured to draw a combustible gas mixture into the combustion chamber 21, and the intake port 23 is covered by an intake valve (not shown) that can be opened and closed.
The exhaust port has an exhaust port 24 that is configured to exhaust the exhaust gas remaining in the combustion chamber 21 after the explosive combustion to the outside of the combustion chamber 21, and the exhaust port 24 is covered by an exhaust valve (not shown) that can be opened and closed.
The intake valve or exhaust valve is configured to open and close the intake port 23 or exhaust port 24 in response to the rotation of the crankshaft 19, i.e., the movement of the piston 11, using a cam, rocker arm, or the like.
As a result, by alternately supplying a combustible gas mixture into the combustion chambers 21, 21 provided at both the left and right ends of the cylinder 20 and causing it to explode and burn, the piston 11 can be caused to reciprocate left and right as shown in Figure 4, and the crankshaft 19 can be rotated.

The engine 10 having the above-described configuration operates as follows, which will be explained below with reference to the accompanying drawings.
FIG. 4 is an explanatory diagram showing the positional relationship between the internal gear 14a and the gear 15 when the gear 15 rotates along the internal gear 14a in accordance with the reciprocating motion of the piston 11 in the cylinder 20a.

The ratio of the inner diameter R of the internal gear 14a formed on the inner periphery of the through hole 14 to the outer diameter r of the gear 15 journaled by the crank pin 17 is set to 2 to 1. Therefore, the crank arm 18 rotates in response to the reciprocating motion of the internal gear 14a, i.e., the piston 11 having the through hole 14, as follows: As shown in Figure 4, the travel distance of the piston head 12 on the right end side of the piston 11 is L, the starting point on the right end side, i.e., the top dead center position, is L0, and the ending point on the left end side, i.e., the bottom dead center position, is L1.
4(a) shows the case where the left end of the internal gear 14a and the left end of the gear 15 are in contact and the piston head of the piston 11 is at top dead center L0. This is the initial position where rotation of the gear 15 begins. From this point, the gear 15 rotates clockwise in the direction of arrow T, and the eccentric free rotor 16 rotates counterclockwise in the direction of arrow F.
4(b) shows the case where the gear 15 has rotated a half turn clockwise from the state shown in FIG. 4(a) and is now in contact with the lower end of the internal gear 14a. At this time, the position of the right piston head 12 is at position L/2 midway through its forward movement.
4(c) shows the case where the gear 15 has rotated clockwise once from the position shown in FIG. 4(a) and is now in contact with the right end of the internal gear 14a. At this time, the position of the right piston head 12 is at bottom dead center L1, and the reciprocating motion of the piston 11 turns back from this point.
Figure 4(d) shows the case where the gear 15 has rotated a half turn clockwise from Figure 4(c) and is now in contact with the upper end of the internal gear 14a. At this time, the position of the right piston head 12 is at position L/2 on the way back.
Furthermore, when the gear 15 rotates a half turn from the position shown in Fig. 4(d), the gear 15 returns to the initial position shown in Fig. 4(a). At this time, the crank arm 18 rotates once, causing the crankshaft 19 to rotate once, and the position of the right piston head 12 returns to the top dead center L0.
By repeating the above operation, the linear reciprocating motion of the piston 11 can be converted into the rotational motion of the crankshaft 19 via the rotational motion of the gear 15 that meshes with the internal gear 14 a in the through hole 14 .

As shown in Figure 4, the axis of the eccentric free rotor 16 is displaced at a position along the length of the crank arm 18 from the crankshaft 19 to the crankpin 17 in accordance with the displacement of the rotation axis of the gear 15, i.e., the crankpin 17, and the eccentric free rotor 16 rotates within the through hole 14 counterclockwise (indicated by arrow F), which is opposite to the rotation direction of the gear 15.
As a result, when the piston 11 reciprocates, the eccentric free rotor 16 fitted into the through hole 14 slides while displacing its axis within the through hole 14, so that the force that the piston 11 receives from the piston head 12 due to combustion explosion is received by the eccentric free rotor 16, preventing distortion of the through hole 14.

Next, as shown in FIG. 4, the steps that take place in the combustion chambers 21, 21 when the piston 11 is reciprocated in the cylinder 20a will be described.
The engine 10 shown in Figures 1 to 4 is a four-stroke engine that repeats an intake stroke, a compression stroke, an explosion stroke, and an exhaust stroke. Here, the operation of the right piston head 12 of the piston 11 shown in Figure 4 will be described.
The intake stroke is a process that occurs when the right piston head 12 moves from top dead center L0 to bottom dead center L1 as shown in Figure 4(c) through Figure 4(a) and Figure 4(b). This causes a combustible gas mixture to be drawn into the combustion chamber 21 and the cylinder 20.
The compression stroke is a process that occurs when the right piston head 12 moves from bottom dead center L1 toward top dead center L0 as shown in Figure 4(a) through Figure 4(c) to Figure 4(d). As a result, the combustible gas mixture filling the cylinder 20 is compressed toward the combustion chamber 21.
The explosion stroke is a process that occurs when the right piston head 12 moves from top dead center L0 to bottom dead center L1 as shown in Figure 4(c) through Figure 4(a) and Figure 4(b). As a result, the combustible gas mixture compressed in the combustion chamber 21 is ignited by the spark plug, causing explosive combustion.
The exhaust stroke is the process that occurs when the right piston head 12 moves from bottom dead center L1 toward top dead center L0 as shown in Figure 4(a) through Figure 4(c) and Figure 4(d). As a result, the piston 11, which has been pressed to bottom dead center L1 by the explosive combustion occurring in the combustion chamber 21, moves toward top dead center L0, and the piston head 12 pushes out the exhaust gases filling the cylinder.
Similarly, each process is repeated in the left piston head 12 of the piston 11. At this time, when the intake stroke is performed on the right side, the compression stroke is performed on the left side, when the compression stroke is performed on the right side, the explosion stroke is performed on the left side, when the explosion stroke is performed on the right side, the exhaust stroke is performed on the left side, and when the exhaust stroke is performed on the right side, the intake stroke is performed on the left side, so that each process is performed alternately on the left and right.
Therefore, the engine 10 shown in FIGS. 1 to 4 is a horizontally opposed two-cylinder engine configured so that each process is performed alternately on the left and right sides.

5 is composed of a piston 11A whose piston length is shorter than that of engine 10, and a cylinder case 20A whose cylinder length is shortened to match the piston 11A. The through-hole 14, and the internal gear, gear, crank pin, crank arm, and crankshaft within the through-hole 14 are the same as those of engine 10, so a description thereof will be omitted. As such, the engines 10, 10A according to this embodiment are configured so that the pistons 11, 11A reciprocate linearly within the cylinders of the cylinder cases 20, 20A without using connecting rods, and therefore piston slap, in which the piston swings around the piston pin due to tilt of the connecting rod and hits the bore wall, can be minimized.
Therefore, the piston skirt length can be minimized, as in the case of piston 11A shown in Figure 5. This allows engine 10A to be configured with a short overall length of piston 11A, making engine 10A compact and lightweight, and also reducing the amount of oil used to protect the piston.

The engine 10 according to this embodiment is configured so that the piston 11 reciprocates linearly. This makes it possible to suppress the oscillation and vibration caused by the moment of the connecting rod, which is caused by the omission of the connecting rod, compared to a conventional engine in which the piston is linked to the crank arm by a connecting rod. Furthermore, a balance weight that is provided on the opposite side of the piston to offset such vibration can be omitted or made lighter, which, together with the omission of the connecting rod, also contributes to a reduction in the weight of the engine 10.
Furthermore, since the piston 11 has a simple structure consisting of an approximately cylindrical body, the cylinder inner diameter, i.e., the stroke length of the bore and piston 11, can be freely designed, and the engine 10 can be freely designed from a short stroke to a long stroke depending on the intended use of the engine 10.

Furthermore, the shape of the piston according to this embodiment is not limited to the configuration of the pistons 11, 11A shown in Figures 1 to 4 and Figure 5, but may be, for example, the configuration shown in Figures 6 to 8.
The piston 11B shown in Figure 6 has a diameter that is smaller near the through hole 14 than the diameter of the piston skirts 13, 13, and has a constricted shape around the center of the peripheral wall portion near the through hole 14 of the piston 11B.
The piston 11C shown in Figure 7 has a diameter that gradually increases from the piston skirts 13, 13 toward the vicinity of the through hole 14, and the center of the peripheral wall of the through hole 14 of the piston 11B is bulged out into an approximately spherical shape.
In this way, by configuring the diameter of the piston skirts 13, 13 connected to the piston heads 12, 12 to be different from the diameter of the piston skirts 13, 13 near the through hole 14, for example, in the case of Figure 6, the bore can be enlarged while the sizes of the internal gears 14 and gears 15 remain the same, resulting in a short stroke, and in the case of Figure 7, the bore can be made smaller while the sizes of the internal gears 14 and gears 15 remain the same, resulting in a long stroke.
8 has a shape in which the front and rear peripheral wall portions are cut out along the axial direction of the through-hole 14, and the through-hole 14 is opened in the flat plate-like planar portion 11a connected to the piston skirts 13, 13. This makes it possible to reduce the weight of the piston 11D by the amount of the cutout compared to the generally cylindrical piston 11.

1 is a horizontally opposed two-cylinder engine with a crank phase angle of 180 degrees (π), in which the opposing piston heads 12 alternately perform explosions, as in a conventional engine. The engine 10 as a whole is configured to perform unequal explosions, in which two explosion strokes occur consecutively on the left and right, followed by a period in which no explosion stroke occurs on either side. Engine 10B was configured to suppress vibrations associated with these unequal explosions.
The engine 10B shown in Figure 9 is configured by extending the crankshaft 19 to form one unit, the engine 10 shown in Figure 1, and arranging two of these units side by side to form a horizontally opposed four-cylinder engine. Each unit is referred to as a first unit 30 and a second unit 31. The configurations of the pistons 11 and cylinder cases 20 are the same as those described above, so a description thereof will be omitted.
Here, the crank phase angle formed by the crank arm 18 of the second unit 31 relative to the crank arm 18 of the first unit 30 is configured to be 180 degrees (π). This allows the pistons on the first unit 30 side and the pistons on the second unit 31 side to alternately reciprocate, thereby canceling out horizontal vibrations. Furthermore, by combining the non-uniform explosions occurring in one unit with the non-uniform explosions occurring in the other unit, the engine 10B as a whole can be configured to perform uniform explosions. The uniform explosions will be described below.

The horizontally opposed four-cylinder engine 10B having the above-described configuration operates as follows, which will be explained below with reference to the accompanying drawings.
The phase difference between the crank angles of the first crank arm 13a and the second crank arm 13b of the horizontally opposed four-cylinder engine 10C is 180 degrees (π).
9, when the right piston head 12R of the piston 11 on the first unit 30 side is at bottom dead center L1 and the left piston head 12L is at top dead center L0, the right piston head 12R of the piston 11 on the second unit 31 side is at top dead center L0 and the left piston head L is at bottom dead center L1. In this way, the engine 10B operates with a linear reciprocating motion such that the pistons 11 of the first unit 30 and the pistons 11 of the second unit 31 alternate in opposite directions.
The relationship between the piston heads 12, 12 of each unit 30, 31 in each process is shown in Table 1. The arrows in the table indicate the phase direction of the crank arm 18 of the first unit 30 and the crank arm 18 of the second unit 31. For example, when the arrow is "→" for the first unit 30, the second unit 31, which has a phase difference of 180 degrees (π), is moving in the opposite direction "←".

As shown in Table 1, in the engine 10B, in the first row of item number 1, when the left piston head 12L of the first unit 30 is performing an intake stroke, the piston 11 of the first unit 30 moves horizontally toward the right piston head 12R, and therefore the right piston head 12R is performing a compression stroke. At this time, in the second unit 31, which has a phase difference of 180 degrees (π), the right piston head 12R is performing an explosion stroke, the piston 11 of the second unit 31 moves horizontally toward the left piston head 12L, and the left piston head 12L is performing an exhaust stroke.
The explosion process performed by the right piston head 12R of the second unit 31 in line 1 is then performed sequentially by the right piston head 12R of the first unit 30 in line 2, the left piston head 12L of the same unit 30 in line 3, and the left piston head 12L of the second unit 31 in line 4.
In this way, by allocating the explosion strokes to be performed sequentially at the four piston heads, it is possible to configure the engine 10B so that the explosion stroke is always performed in one of the combustion chambers 21 during each stroke performed by the four cylinders at both ends of the first unit 30 and the second unit 31. Therefore, when viewed as a whole, the engine 10B can be configured to perform explosions at equal intervals.
Furthermore, because the pistons 11 of the first unit 30 and the second unit 31 alternately perform linear reciprocating motion in opposite directions, vibrations caused by the movement of the pistons 11 can be canceled out, the side pressure generated when the piston skirt presses against the inner wall of the cylinder 20 can be suppressed, and friction loss when the piston skirt slides along the inner wall of the cylinder can be reduced. As a result, vibrations or noises caused by contact between the piston and the cylinder can be suppressed.

Next, with respect to the engine 10 described in the first embodiment, several examples of other embodiments suited to the intended use will be illustrated with reference to the accompanying drawings.
10 to 13 are explanatory diagrams showing the outline of the configuration when the four-stroke engine 10 shown in the first embodiment is converted into two-stroke engines 10C, 10D, 10E, and 10F.

The pistons 11 of the engines 10C, 10D, and 10E have the same configuration as that of the first embodiment, and therefore will not be described here. The cylinder case also has the same basic configuration as the cylinder case 20 of the first embodiment, with combustion chambers 21, 21 of a predetermined shape formed at both ends of a cylindrical cylinder 20a and a spark plug 22 disposed at a predetermined position in the combustion chamber 21.
The difference between the engine 10 according to the first embodiment and the engines 10C, 10D, and 10E according to the second embodiment is the positions of the intake ports of the intake ports and the exhaust ports of the exhaust ports provided at predetermined positions on the peripheral wall of the cylinder 20a.
In this way, according to the engine of the second embodiment, by changing the configuration of the cylinder case 20, the configuration can be easily changed from a four-stroke type to a two-stroke type, or vice versa.

The engine 10C shown in Figure 10 has a cylinder case 20B equipped with a cylindrical cylinder 20b. The cylinder 20b has combustion chambers 21, 21 connected to each other at both ends. The peripheral wall of the cylinder 20b is also formed with an intake port 23b and an exhaust port 24b.
The intake ports 23b are formed near the bottom dead center L1 of the piston heads 12, 12 at both left and right ends of the piston 11. The intake port having the intake ports 23b is branched in a T shape so that the combustible gas mixture can be drawn into the combustion chambers at both left and right ends. A piston reed valve 35 is disposed near the intake ports 23b so that the combustible gas mixture can be drawn in one direction toward the cylinder 20. This prevents the combustible gas mixture or post-explosion exhaust gas from flowing back from the cylinder 20b side toward the intake port.
The exhaust ports 24b are formed near the combustion chamber 21 and near the top dead center L0 of the piston heads 12, 12, respectively.
As described above, the engine 10C shown in FIG. 10 has a configuration known as a piston reed valve type two-stroke engine.

While the spark plug 22 is not shown in Figure 10, similar to the engine described in the first embodiment, a combustible gas mixture formed by mixing fuel sprayed from a carburetor or injector with air in a predetermined ratio generates a spark from the electrode of the spark plug 22 when compressed by the piston 11 in the combustion chamber 21. When the spark explodes and burns the combustible gas mixture in the combustion chamber, pressure is applied to the piston head 12, causing the piston 11 to move. As described in the first embodiment, the combustible gas mixture is formed by spraying gasoline or alcohol into air, but this is not limited to this. The engine may also be an internal combustion engine that explodes or burns combustible gas extracted from natural gas, hydrogen gas, biomass, or the like. Furthermore, instead of a spark plug, an injection device (not shown) that atomizes and sprays liquid fuel may be provided, and a spray port communicating with the injection device may be provided in the combustion chamber 21. In this case, a diesel engine can be constructed in which fuel such as diesel is sprayed into high-temperature, high-pressure air compressed by the piston head 12 and combusted.

The engine 10C having the above configuration operates by performing an intake/compression stroke and a combustion/exhaust/scavenging stroke during one reciprocating motion of the piston 11.
The intake and compression stroke refers to the process of drawing in and compressing a combustible gas mixture into cylinder 20b and combustion chambers 21, 21. In this stroke, when piston 11 is at bottom dead center L1, intake port 23b and exhaust port 24b are exposed inside cylinder 20b, and the combustible gas mixture is drawn into cylinder 20b from the intake port, where negative pressure is generated as piston head 12 moves to bottom dead center L1.
After intake, the piston reed valve 35 closes the intake port, preventing exhaust gas from flowing back into the intake port. As the piston head 12 moves from bottom dead center L1 toward top dead center L0, closing the intake port 23b and exhaust port 24b in turn, the piston head 12 compresses the combustible gas mixture toward the combustion chamber 21.
The combustion, exhaust, and scavenging stroke involves combusting and expelling the compressed combustible mixture, exhausting the resulting exhaust gas, and scavenging the exhaust gas from cylinder 20b when a new combustible mixture is drawn in. In this stroke, the compressed combustible mixture is ignited by a spark plug (not shown) in combustion chamber 21, resulting in combustion and explosion. The resulting combustion pressure moves piston head 12 from top dead center L0 toward bottom dead center L1. At this time, exhaust port 24b is first exposed in cylinder 20b, exhausting the exhaust gas, and generating negative pressure within cylinder 20b, whose volume continues to expand. Then, when intake port 23b is exposed, the combustible mixture is drawn into cylinder 20b. After intake, piston reed valve 35 closes the intake port, preventing exhaust gas from flowing back into the intake port. When the piston head 12 moves from the bottom dead center L1 toward the top dead center L0, the remaining exhaust gas in the cylinder 20b is scavenged through the exhaust port.

11, the piston 11 and the cylinder 20b of the engine 10D are similar to those of the engine 10C, and therefore a detailed description thereof will be omitted. The difference between the engines 10C and 10D is the presence or absence of a crankcase 36. The crankcase 36 houses the crankshaft 19 and the crank arm 18 and is configured to surround the vicinity of the through-hole 14 of the piston 11 together with the cylinder 20b.
The crankcase 36 has an intake port with an intake port 23c formed therein and extending radially from the crankshaft 19. This allows the combustible gas mixture to be drawn into the crankcase 36 from the intake port 23c through the intake port. A crankcase reed valve 37 is also disposed in the intake port. This prevents the combustible gas mixture or post-explosion exhaust gas from flowing back from the crankcase 36 into the intake port.
Furthermore, both ends of the cylinder 20b, which is connected to the crankcase 36 and the combustion chambers 21, 21, are connected by a pair of bypass ports 38, which are configured to allow a combustible gas mixture to be supplied from the crankcase 38 to the combustion chambers 21, 21. An open end 38a on the cylinder side of the bypass is formed near the bottom dead center L1 of the piston head 12.
Although the present embodiment illustrates a schematic configuration of the crankcase 36, the crankcase 36 has an intake/exhaust pressure adjusting chamber that is divided into at least two chambers along the axial direction of the piston 11. The intake/exhaust pressure adjusting chamber is in communication with the combustion chambers 21, 21 formed adjacent to each other at both ends of the cylinder 20b through a bypass port 38. Each intake/exhaust pressure adjusting chamber is configured so that when the eccentric free rotor 16, which rotates around the crankshaft 19, pressurizes one chamber, the other chamber is depressurized. As a result, the intake/exhaust pressure adjusting chamber is alternately depressurized and pressurized. During depressurization, a combustible gas mixture is supplied through the intake port 23c, and the pressurized combustible gas mixture is then drawn into the combustion chamber 21 through the bypass port 38.
On the other hand, the exhaust port has an exhaust outlet 24b formed near the top dead center L0 of the piston head 12 on the combustion chamber 21 side, similar to the engine 10C described above.
As described above, the engine 10D shown in FIG. 11 has a configuration known as a crankcase reed valve type two-stroke engine.

While the spark plug 22 is not shown in Figure 11, similar to the engine described in the first embodiment, a combustible gas mixture formed by mixing fuel sprayed from a carburetor or injector with air in a predetermined ratio generates a spark from the electrode of the spark plug 22 when compressed by the piston 11 in the combustion chamber 21. When the spark explodes and burns the combustible gas mixture in the combustion chamber, pressure is applied to the piston head 12, causing the piston 11 to move. As described in the first embodiment, the combustible gas mixture is formed by spraying gasoline or alcohol into air, but this is not limited to this. The engine may also be an internal combustion engine that explodes or burns combustible gases extracted from natural gas, hydrogen gas, biomass, etc. Furthermore, instead of a spark plug, an injection device (not shown) that atomizes and sprays liquid fuel may be provided, and a spray port communicating with the injection device may be provided in the combustion chamber 21. In this case, a diesel engine can be constructed in which fuel such as diesel is sprayed into high-temperature, high-pressure air compressed by the piston head 12 and combusted.

The engine 10D having the above configuration operates in the same manner as the engine 10C, performing an intake/compression stroke and a combustion/exhaust/scavenging stroke during one reciprocating motion of the piston 11. These operations are similar to those of the engine 10C, and therefore will not be described here.
The difference in operation between engine 10D shown in FIG. 11 and engine 10C described above is due to the difference between the crankcase reed valve 37 and bypass port 38 provided in engine 10D and the piston reed valve 35 provided in engine 10C.
In the case of the engine 10D, the combustible gas mixture is decompressed by the eccentric free rotor 16 in the crankcase 36 and is drawn into the intake/exhaust pressure adjusting chamber on the side where negative pressure is generated. Meanwhile, the combustible gas mixture in the intake/exhaust pressure adjusting chamber is pressurized by the eccentric free rotor. By repeating this alternating decompression and pressurization, the combustible gas mixture can be sent alternately to the combustion chambers 21, 21 connected to both the left and right ends of the cylinder 20b.
During the intake and compression strokes, when the piston head 12 is located at bottom dead center L1, the combustible gas mixture pressurized in the intake/exhaust pressure adjusting chamber is drawn into the cylinder 20b through the open end 38a of the bypass port 38. When the piston head 12 then moves from bottom dead center L1 to top dead center L0 and the exhaust port 24b is closed, the combustible gas mixture is compressed in the combustion chamber 21.
Next, in the combustion, exhaust, and scavenging stroke, the compressed combustible gas mixture is ignited and combusts, exerting combustion pressure on the piston head 12. As the piston head 12 moves from top dead center L0 to bottom dead center L1, the exhaust port 24b is exposed, allowing exhaust gas to be discharged. As the piston head 12 moves, negative pressure is generated in the combustion chamber 21 and the cylinder 20b, while the eccentric free rotor 16 pressurizes the combustible gas mixture in the intake/exhaust pressure adjusting chamber of the crankcase 36. As the piston head 12 moves further, the open end 38a of the bypass port 38 is exposed, allowing the pressurized combustible gas mixture in the intake/exhaust pressure adjusting chamber to be drawn into the cylinder 20b and scavenge the exhaust gas remaining in the cylinder 20b through the exhaust port 24b.
In this way, in the engine 10D, the eccentric free rotor 16 in the crankcase 36 can pressurize the combustible gas mixture in the intake/exhaust pressure adjusting chamber that is connected to the left and right cylinders 20b and the combustion chambers 21, 21, and send it to the cylinders 20b, or reduce the pressure to generate negative pressure and take it in through the intake port. This improves the intake efficiency of the combustible gas mixture and the exhaust/scavenging efficiency of the exhaust gas, thereby improving fuel economy.

12 differs from the engines 10C and 10D in the shape of the eccentric free rotor 16. The eccentric free rotor 16 has a pair of notches 16b formed by cutting out arc-shaped portions of a peripheral edge 16a at predetermined positions.
The engine 10E also has a crankcase 36 that houses the crankshaft 19 and the crank arms 18 and is configured to surround the cylinder 20b. An intake port having an intake port 23d is connected to the crankcase 36 along the axial direction of the crankshaft.
The intake port 23d is disposed to face the peripheral edge 16a and the notch 16b of the eccentric free rotor 16. This prevents the combustible gas mixture drawn into the crankcase 36 through the intake port from flowing back toward the intake port when the intake port 23d overlaps with the peripheral edge 16a and is closed. On the other hand, when the intake port 23d overlaps with the notch 16b and is exposed inside the crankcase 36, the combustible gas mixture can be drawn into the crankcase 36. Since the eccentric free rotor 16 rotates in synchronization with the rotation of the crankshaft 19, the intake port 23d can be exposed by the notch 16b to open and then covered by the peripheral edge 16a to close, and this cycle can be repeated at a predetermined interval.
Furthermore, the crankcase 36 and the combustion chambers 21, 21 provided at both the left and right ends of the cylinder 20b are connected by a pair of bypass ports 38, so that a combustible gas mixture can be supplied from the crankcase 36 to the combustion chambers 21, 21. An open end 38a on the cylinder side of the bypass port 38 is formed near the bottom dead center L1 of the piston head 12.
Although the present embodiment illustrates a schematic configuration of the crankcase 36, the crankcase 36 has an intake/exhaust pressure adjusting chamber that divides the interior into at least two chambers along the axial direction of the piston 11. The intake/exhaust pressure adjusting chamber communicates with the combustion chambers 21, 21 formed adjacent to each other at both ends of the cylinder 20b through a bypass port 38. Each intake/exhaust pressure adjusting chamber is configured so that when the eccentric free rotor 16, which rotates around the crankshaft 19, pressurizes one chamber, the other chamber is depressurized. This allows the intake/exhaust pressure adjusting chamber to alternately depressurize and pressurize. During depressurization, a combustible gas mixture is supplied through the intake port 23d, which overlaps with the notch 16b. The pressurized combustible gas mixture is then drawn into the combustion chamber 21 through the bypass port 38. Here, while the eccentric free rotor 16 makes one rotation, i.e., while the piston makes one reciprocating motion, pressurization and depressurization processes are carried out sequentially in each intake/exhaust pressure adjusting chamber, and in order to sequentially send the combustible gas mixture to each combustion chamber 21, 21 provided at both the left and right ends of the cylinder 20b, the cutouts 16b are arranged opposite to each other at predetermined positions on the periphery of the eccentric free rotor 16. This makes it possible to sequentially send the combustible gas mixture alternately through the bypass port 38 to each combustion chamber 21, 21 at both the left and right ends of the engine 10E shown in Figure 12.
On the other hand, the exhaust port has an exhaust outlet 24b formed near the top dead center L0 of the piston head 12 on the combustion chamber 21 side, similar to the engines 10C and 10D.
As described above, the engine 10E shown in FIG. 12 has a configuration known as a rotary disc valve type two-stroke engine.

While the spark plug 22 is not shown in Figure 12, similar to the engine described in the first embodiment, a combustible gas mixture formed by mixing fuel sprayed from a carburetor or injector with air in a predetermined ratio generates a spark from the electrode of the spark plug 22 when compressed by the piston 11 in the combustion chamber 21. When the spark explodes and burns the combustible gas mixture in the combustion chamber, pressure is applied to the piston head 12, causing the piston 11 to move. As described in the first embodiment, the combustible gas mixture is formed by spraying gasoline or alcohol into air, but this is not limited to this. The engine may also be an internal combustion engine that explodes or burns combustible gas extracted from natural gas, hydrogen gas, biomass, or the like. Furthermore, instead of a spark plug, an injection device (not shown) that atomizes and sprays liquid fuel may be provided, and a spray port communicating with the injection device may be provided in the combustion chamber 21. In this case, a diesel engine can be constructed in which fuel such as diesel is sprayed into high-temperature, high-pressure air compressed by the piston head 12 and combusted.

The engine 10E having the above configuration operates in the same manner as the engines 10C and 10D, performing an intake/compression stroke and a combustion/exhaust/scavenging stroke during one reciprocating motion of the piston 11. These operations are similar to those of the engine 10C, and therefore will not be described here.
The differences in operation between engine 10E shown in Figure 12 and engine 10D shown in Figure 11 are the rotary disc valve and crankcase reed valve using eccentric free rotor 16, and the difference between intake ports provided along the axial direction of crankshaft 19 and intake ports provided along the radial direction of the crankshaft.
In the case of the engine 10E, when the intake port 23d overlapping the notch 16b is exposed to the intake/exhaust pressure adjusting chamber as the eccentric free rotor 16 rotates, the pressure inside the intake/exhaust pressure adjusting chamber is reduced by the eccentric free rotor 16, creating a negative pressure, allowing the combustible gas mixture to be smoothly drawn into the intake/exhaust pressure adjusting chamber. Then, when the peripheral edge 16a of the eccentric free rotor 16 covers and closes the intake port 23d, the chamber is pressurized, and the air is drawn into the cylinder 20b through the bypass port 38. The timing of the decompression and pressurization within the intake/exhaust pressure adjusting chamber can be overlapped with the intake/compression stroke and the explosion/exhaust/scavenging stroke of a two-stroke engine as follows:
During the intake and compression strokes, when the piston head 12 is located at bottom dead center L1, the combustible gas mixture pressurized in the intake/exhaust pressure adjusting chamber is drawn into the cylinder through the open end 38a of the bypass port 38. When the piston head 12 then moves from bottom dead center L1 to top dead center L0 and the exhaust port 24b is closed, the combustible gas mixture is compressed in the combustion chamber 21.
Next, in the combustion, exhaust, and scavenging stroke, the compressed combustible gas mixture is ignited and combusts, pressing the piston head 12 with combustion pressure. As the piston head 12 moves from top dead center L0 to bottom dead center L1, the exhaust port 24b is exposed and the exhaust gas is discharged. As the piston head 12 moves, negative pressure is generated in the combustion chamber 21 and the cylinder 20b, while the combustible gas mixture is pressurized by the eccentric free rotor 16 in the intake/exhaust pressure adjusting chamber. As the piston head 12 moves further, the open end 38a of the bypass port 38 is exposed, and the pressurized combustible gas mixture is drawn into the cylinder 20b, scavenging any remaining exhaust gas through the exhaust port 24b.
In this way, in the engine 10E, the combustible gas mixture can be alternately drawn into the left and right combustion chambers 21, 21 while the eccentric free rotor 16 makes one rotation within the through-hole 14. This improves the intake efficiency of the combustible gas mixture and the exhaust and scavenging efficiency of the exhaust gas, thereby improving fuel economy.

An engine 10F shown in FIG. 13 is a horizontally opposed four-cylinder engine based on the crankcase reed valve type two-stroke engine 10D described above.
The engine 10F is composed of a third unit 40 and a fourth unit 41, each of which is a horizontally opposed two-cylinder engine according to the engine 10D. The pistons 11 and cylinders 20b of each unit are similar in configuration to those of the engine 10D, and therefore will not be described here.
The third unit 40 and the fourth unit 41 are arranged side by side along the direction of the crankshaft 19. The crankcase 36A of the engine 10F is provided to surround the vicinity of the crankshaft 19 of the third unit 40 and the fourth unit 41 together with the cylinder 20b.
13, the engine 10F has a crank arm 18 associated with the third unit 40 and a crank arm 18 associated with the fourth unit 31. The crank arms 18 are arranged facing each other in opposite directions across the crankshaft 19, and are configured to form a crank angle of 180 degrees (π) with respect to each other.
The crankcase 36A is provided with an intake port having an intake port 23c extending radially from the crankshaft 19 between the third unit 40 and the fourth unit 41, and the intake port is provided with a crankcase reed valve (not shown) similar to that of the engine 10D. Furthermore, a bypass port 38 is provided between the crankcase 36A and the cylinder 20b so as to communicate with the combustion chambers 21, 21 of the third unit 40 and the fourth unit 41.
Although the present embodiment illustrates a schematic configuration of the crankcase 36A, the crankcase 36A has an intake/exhaust pressure adjusting chamber that is divided into at least four chambers along the axial direction of the piston 11. The intake/exhaust pressure adjusting chambers are connected to the combustion chambers 21, 21 formed at both ends of the cylinder 20b of each unit 40, 41 through bypass ports 38. Each intake/exhaust pressure adjusting chamber is configured so that when the eccentric free rotor 16, which rotates around the crankshaft 19, pressurizes one chamber, the other chamber is depressurized. As a result, the intake/exhaust pressure adjusting chamber is alternately depressurized and pressurized. During depressurization, a combustible gas mixture is supplied through the intake port 23c. The pressurized combustible gas mixture is then drawn into the combustion chamber 21 through the bypass port 38.
On the other hand, the exhaust port has an exhaust outlet 24b formed near the top dead center L0 of the piston head 12 on the combustion chamber 21 side, similar to the engine 10D described above.
Similarly to the engine described in the first embodiment, the spark plug 22 is configured to emit a spark from an electrode of the spark plug 22 when a combustible gas mixture formed by mixing fuel sprayed from a carburetor or injector with air in a predetermined ratio is compressed by the piston 11 in the combustion chamber 21. When the spark explodes and burns the combustible gas mixture in the combustion chamber, pressure is applied to the piston head 12, causing the piston 11 to move. As described in the first embodiment, the combustible gas mixture is formed by spraying gasoline or alcohol into air, but this is not limited thereto. The internal combustion engine may also explode or burn combustible gas extracted from natural gas, hydrogen gas, biomass, or the like. Furthermore, instead of a spark plug, an injection device (not shown) that atomizes and sprays liquid fuel may be provided, and a spray port communicating with the injection device may be provided in the combustion chamber 21. In this case, a diesel engine can be configured in which fuel such as diesel fuel is sprayed into high-temperature, high-pressure air compressed by the piston head 12 and combusted.
As described above, the engine 10F shown in FIG. 13 has a configuration in which a so-called crankcase reed valve type two-stroke engine is assembled into a horizontally opposed four-cylinder engine.

The engine 10F having the above-described configuration operates as follows, which will be explained below with reference to the accompanying drawings.
The crank arm 18 of the third unit 40 and the crank arm 18 of the fourth unit 41 are configured so that the phase difference in crank angle is 180 degrees (π).
13, when the right piston head 12R of the third unit 40 is at bottom dead center L1 and the left piston head 12L is at top dead center L0, the right piston head 12R of the fourth unit 41 is at top dead center L0 and the left piston head 12L is at bottom dead center L1. In this way, the pistons 11 of the third unit 40 and the fourth unit 41 perform linear reciprocating motions in alternately opposite directions, whereby the left and right piston heads 12R, 12L of the third unit 40 and the left and right piston heads 12R, 12L of the fourth unit 41 perform linear reciprocating motions in alternately opposite directions.
The relationship between the piston heads 12R, 12L of each unit 40, 41 in each process is shown in Table 2 below. The arrows in the table indicate the phase direction of the crank arm 18. For example, when the piston 11 in the third unit 40 moves according to the arrow "→", the piston 11 in the fourth unit 41, which has a phase difference of 180 degrees (π), moves in the opposite direction "←".

As shown in Table 2, in the first row of the column, when the left piston head 12L of the third unit 40 is performing the intake/compression stroke, the piston 11 of the third unit 40 moves horizontally toward the left piston head 12L, and therefore the combustion/exhaust/scavenging stroke is performed on the right piston head 12R side. At this time, in the fourth unit 41, which has a phase difference of 180 degrees (π) with the third unit 40, the right piston head 12R performs the intake/compression stroke, the piston 11 of the fourth unit 41 moves horizontally toward the right piston head 12R, and the left piston head 12L performs the combustion/exhaust/scavenging stroke.
Conversely, in the second line, the intake and compression strokes are performed by the right piston head 12R of the third unit 40 and the left piston head 12L of the fourth unit 41, and the combustion, exhaust and scavenging strokes are performed by the left piston head 12L of the third unit 40 and the right piston head 12R of the fourth unit 41.
In this way, the engine 10F can be configured so that the explosion stroke is always performed in one of the cylinders 20 in the third unit 40 and the fourth unit 41. Therefore, explosions can be performed at equal intervals throughout the entire engine 10F.
Furthermore, because the pistons 11 of the third unit 40 and the fourth unit 41 alternately perform linear reciprocating motion in opposite directions, vibrations caused by the movement of the pistons 11 can be canceled out, the side pressure generated when the piston skirt 13 presses against the inner wall of the cylinder 20b can be suppressed, and friction loss when the piston skirt 13 slides along the inner wall of the cylinder can be reduced. As a result, vibrations or noises caused by contact between the piston 11 and the cylinder 20b can be suppressed.
Although not explained here, even if a horizontally opposed four-cylinder engine is constructed based on the piston reed valve type engine 10C or the rotary disc valve type engine 10E, the same effects as those of the crankcase reed valve type engine can be obtained.

Furthermore, while the above describes an example of a horizontally opposed four-cylinder engine, the number of cylinders in a horizontally opposed engine is not limited to this, and horizontally opposed engines with six, eight, ten, twelve, sixteen, etc. cylinders may be configured by adding or removing the horizontal two-cylinder units of the basic configuration of engines 10C, 10D, and 10E. In this case, the phase difference between each unit is set to a predetermined angle, such as 120 degrees (4π/3), 72 degrees (π/5), 60 degrees (π/3), or 45 degrees (π/4), preferably so that the crank arms 18 of each unit are balanced around the crankshaft 19. This allows vibrations such as primary vibrations, even vibrations, and secondary vibrations to be canceled out between the units.
In either case, a balance weight may be attached to the crankshaft 19 to suppress vibration.
In each engine configured as described above, the length of the crank arm 18 revolving around the crankshaft 19 can be made shorter than the length of the crank arm in a conventional engine, allowing for a reduction in the weight of the balance weight that cancels out the moment of inertia revolving around the crankshaft 19. Furthermore, in a conventional connecting rod, whose tip end reciprocates and whose base end rotates, vibrations due to the reciprocating motion and vibrations due to the rotational motion occur. However, the engine according to this embodiment, which does not include such a connecting rod, can eliminate the vibration components and causes of vibration caused by the operation of the connecting rod. This makes it possible to eliminate the effects of connecting rod operation among the primary vibration, even-force vibration, secondary vibration, and other vibrations that occur in the engine.

Next, another embodiment of the engine of the present invention will be described with reference to the accompanying drawings.
FIG. 14 is an explanatory diagram showing the outline of the configuration of a piston provided in the engine according to the third embodiment, and FIG. 15 is a plan view showing the outline of the configuration of the engine according to the third embodiment.

As shown in FIG. 15, the engine 10G has a piston 11B and a cylinder case 20C.
As shown in FIG. 14, the piston 11B is composed of a pair of small diameter portions 50, 50 and a large diameter portion 51 sandwiched between the small diameter portions 50, 50 along the axial direction of the piston 11B.
The small diameter portions 50, 50 have piston heads 12, 12 on the end surfaces opposite the large diameter portion 51, and a piston skirt 13 is formed to connect the piston heads 12, 12 to the large diameter portion 51 side.
The large diameter portion 51 is formed on the same axis as the small diameter portions 50, 50 and the piston 11B. Shoulders 52 are formed on both end faces of the large diameter portion 51 that contact the small diameter portions 50, 50. A through hole 14 having a predetermined inner diameter is formed in the center of the peripheral wall of the large diameter portion 51 along the radial direction of the large diameter portion 51.

14, the through hole 14 has an internal gear 14a. The internal gear 14a is configured by arranging teeth cut along the axial direction of the through hole 14 in parallel along the circumferential direction of the inner wall of the through hole 14.
As shown in FIG. 14, a gear 15 and an eccentric free rotor 16 are disposed within the through hole 14 .
The gear 15 has teeth cut along the axial direction and is configured to mesh with the internal gear 14a so as to be able to roll. The ratio of the diameter r of the gear 15 to the inner diameter R of the internal gear 14a is configured to be 1:2.
The eccentric free rotor 16 is formed in a disk shape with a diameter approximately the same as the inner diameter of the through hole 14, and is slidably and rotatably fitted into the through hole 14. The axis of the eccentric free rotor 16 is located at a position that divides the diameter of the eccentric free rotor 16 into four equal parts, with the ratio of the minor axis to the major axis being 1:3.
The gear 15 and the eccentric free rotor 16 are journalled by a crank pin 17 .

The crank arm 18 has a crank pin 17 at its tip end and a crank shaft 19 at its base end.
When the gear 15 rotates once around the internal gear 14a, the crank arm 18 rotates the crankshaft 19 once. The relationship between the gear 15 and the internal gear is the same as in the engine 10 of the first embodiment, so a description thereof will be omitted. The eccentric free rotor 16 is also the same as in the engine 10 of the first embodiment, so a description thereof will be omitted.

As shown in FIG. 15, the cylinder case 20C is composed of a pair of cylinders 20c into which the small diameter portions 50, 50 of the piston 11B are fitted, and a housing 53 into which the large diameter portion 51 is fitted.
Combustion chambers 21, 21 of a predetermined shape are formed on the side of cylinder 20c opposite housing 53. Each combustion chamber 21 is provided with an ignition plug 22 and an exhaust port equipped with an exhaust port 24c at predetermined positions.

The spark plug 22 is configured to be energized and ignite to produce a spark when a combustible gas mixture formed by mixing fuel sprayed from a carburetor or an injector with air in a predetermined ratio is compressed by the piston 11 in the combustion chamber 21. When the spark causes the combustible gas mixture to explode and burn in the combustion chamber, pressure is applied to the piston head 12, causing the piston 11 to move in the cylinder 20c.
The above-mentioned flammable gas mixture is formed by spraying gasoline or alcohol into the air, but is not limited to this and may also be an internal combustion engine that explodes or burns flammable gas extracted from natural gas, hydrogen gas, biomass, etc.

Alternatively, instead of a spark plug, an injection device (not shown) that sprays liquid fuel in a mist may be provided, and a spray port communicating with the injection device may be provided in the combustion chamber 21. In this case, a diesel engine can be constructed in which fuel such as diesel oil is sprayed into high-temperature, high-pressure air compressed by the piston head 12 and burned.

The exhaust port with the exhaust port 24c is connected to the combustion chamber 21 and has an exhaust valve 54 that covers the exhaust port 24c. The exhaust valve 54 is configured to periodically open and close the exhaust port 24c using a cam, rocker arm, or the like in response to the rotation of the crankshaft 19, i.e., the movement of the piston 11B. This allows the pressure in the combustion chamber 21 to increase when the exhaust port 24c is closed, and allows the exhaust gas remaining in the cylinder 20c and combustion chamber 21 after explosive combustion to be exhausted and scavenged outside the cylinder 20c and combustion chamber 21 when the exhaust port 24c is open.

As shown in Figure 15, an intake port equipped with an intake port 23b is connected to the peripheral wall of the cylinder 20c near the housing 53 side. A piston reed valve 35 is disposed within each intake port, allowing air to be drawn in one direction toward each of the left and right cylinders 20c. This allows a combustible gas mixture to be drawn into each of the left and right cylinders 20c periodically.

15, the housing 53 is configured with a length that allows the large diameter portion 51 of the piston 11B to linearly reciprocate. The shoulder portion 52 of the piston 11B is configured to face the stepped connecting portion between the housing 53 and the cylinder 20c. This prevents the small diameter portion 50 fitted into the cylinder 20c from coming off the cylinder 20b.
In addition, since a space is formed between the housing 53 and the pulled-out small diameter portion 50, excess oil lubricating the inside of the cylinder case 20C accumulates in the space through the piston skirt 13, and the shoulder portion 52 can supply the oil accumulated in the space back to the piston skirt 13 side.
The shoulder portion 52 can push back into the cylinder 20c the combustible gas mixture that has leaked from the cylinder 20c through the gap between the cylinder 20c and the piston skirt 13.

Since the engine 10G having the above configuration has a configuration similar to that of the piston reed valve type engine 10C shown in Figure 10 above, a detailed description of its operation will be omitted.

An engine 10H shown in FIG. 16 is a horizontally opposed four-cylinder engine based on the engine 10G described above.
The engine 10H is configured by a fifth unit 60 and a sixth unit 61, each of which is a horizontally opposed two-cylinder engine according to the engine 10G. The configuration of each unit 60, 61 is the same as that of the engine 10G, and therefore a description thereof will be omitted.
The fifth unit 60 and the sixth unit 61 are arranged side by side along the crankshaft 19 direction.
16, the engine 10H has a crank arm 18 associated with the fifth unit 60 and a crank arm 18 associated with the sixth unit 61. The crank arms 18 are arranged facing each other in opposite directions across the crankshaft 19, and are configured to form a crank angle of 180 degrees (π) with respect to each other.

An intake port 23b is provided at a predetermined position of the cylinder 20c near the bottom dead center L1 of the small diameter portion 50 of the piston 11B. As shown in Figure 16, the intake port provided with the intake port 23b is formed in a T-shape so as to communicate with the intake ports 23b of the opposing fifth unit 60 and sixth unit 61, and has a piston reed valve 35.
Similarly, the exhaust port including the exhaust port 24c and the exhaust valve 54 is formed in a T-shape so as to communicate with the exhaust ports 24c of the fifth unit 60 and the sixth unit 61 that face each other.
This allows the combustible mixture to be drawn into the cylinder 20c and combustion chamber 21 of both the fifth unit 60 and the sixth unit 61, and also allows the exhaust gas to be discharged and scavenged from the cylinder 20c.

Similarly to the engine described in the first embodiment, the spark plug 22 is configured to emit a spark from an electrode of the spark plug 22 when a combustible gas mixture formed by mixing fuel sprayed from a carburetor or injector with air in a predetermined ratio is compressed by the piston 11 in the combustion chamber 21. When the spark explodes and burns the combustible gas mixture in the combustion chamber, pressure is applied to the piston head 12, causing the piston 11 to move. As described in the first embodiment, the combustible gas mixture is formed by spraying gasoline or alcohol into air, but this is not limited thereto. The internal combustion engine may also explode or burn combustible gas extracted from natural gas, hydrogen gas, biomass, or the like. Furthermore, instead of a spark plug, an injection device (not shown) that atomizes and sprays liquid fuel may be provided, and a spray port communicating with the injection device may be provided in the combustion chamber 21. In this case, a diesel engine can be configured in which fuel such as diesel fuel is sprayed into high-temperature, high-pressure air compressed by the piston head 12 and combusted.
As described above, the engine 10H shown in FIG. 16 has a configuration in which a so-called piston reed valve type two-stroke engine is assembled into a horizontally opposed four-cylinder engine.

The engine 10H having the above-described configuration operates as follows, which will be explained below with reference to the accompanying drawings.
The crank arm 18 of the fifth unit 60 and the crank arm 18 of the sixth unit 61 are configured so that the phase difference in crank angle is 180 degrees (π).
16 , when the right piston head 12R of the sixth unit 61 is located at bottom dead center L1 and the left piston head 12L is located at top dead center L0, the right piston head 12R of the fifth unit 60 is located at top dead center L0 and the left piston head 12L is located at bottom dead center L1. In this way, the pistons 11B of the fifth unit 60 and the sixth unit 61 perform linear reciprocating motions in alternately opposite directions, causing the left and right piston heads 12R, 12L of the fifth unit 60 and the left and right piston heads 12R, 12L of the sixth unit 61 to perform linear reciprocating motions in alternately opposite directions. This operation is similar to the operation of the engine 10F, so a detailed description thereof will be omitted.
In this way, the engine 10H can be configured so that the explosion stroke is always performed in one of the cylinders 20c in the fifth unit 60 and the sixth unit 61. Therefore, explosions can be performed at equal intervals throughout the engine 10H.
Furthermore, because the pistons 11B of the fifth unit 60 and the sixth unit 61 alternately perform linear reciprocating motion in opposite directions, vibrations caused by the movement of the pistons 11B can be canceled out, the side pressure generated when the piston skirt 13 presses against the inner wall of the cylinder 20c can be suppressed, and friction loss when the piston skirt 13 slides along the inner wall of the cylinder 20c can be reduced. As a result, the generation of vibrations or noises due to contact between the piston 11 and the cylinder 20c can be suppressed.

Although the above describes an example of a horizontally opposed four-cylinder engine, the number of cylinders in a horizontally opposed engine is not limited to this, and a horizontally opposed engine with six, eight, ten, twelve, sixteen, or other cylinders may be configured by adding or removing the horizontal two-cylinder units of the basic configuration of engine 10G. In this case, the phase difference between each unit is set to a predetermined angle, such as 120 degrees (4π/3), 72 degrees (π/5), 60 degrees (π/3), or 45 degrees (π/4), preferably so that the crank arms 18 of each unit are balanced around the crankshaft 19. This allows vibrations such as primary vibrations, even vibrations, and secondary vibrations to be canceled out between the units.
In either case, a balance weight may be attached to the crankshaft 19 to suppress vibration.
In each engine configured as described above, the length of the crank arm 18 revolving around the crankshaft 19 can be made shorter than the length of the crank arm in a conventional engine, allowing for a reduction in the weight of the balance weight that cancels out the moment of inertia revolving around the crankshaft 19. Furthermore, in a conventional connecting rod, whose tip end reciprocates and whose base end rotates, vibrations due to the reciprocating motion and vibrations due to the rotational motion occur. However, the engine according to this embodiment, which does not include such a connecting rod, can eliminate the vibration components and causes of vibration caused by the operation of the connecting rod. This makes it possible to eliminate the effects of connecting rod operation among the primary vibration, even-force vibration, secondary vibration, and other vibrations that occur in the engine.

Next, another embodiment of the engine of the present invention will be described with reference to the accompanying drawings.
FIG. 17 is an explanatory diagram showing the outline of the configuration of an engine according to the fourth embodiment.

As shown in FIG. 17, the engine 10I has a piston 11C and a cylinder case 20D that houses the piston 11C.
The piston 11C has piston heads 12, 12 at both left and right ends, and has a through hole 14 at the center of the peripheral wall portion.

17, the through hole 14 has an internal gear 14a. The internal gear 14a is configured by arranging teeth cut along the axial direction of the through hole 14 in parallel along the circumferential direction of the inner wall of the through hole 14.
As shown in FIG. 17, a gear 15 and an eccentric free rotor 16 are disposed within the through hole 14 .
The gear 15 has teeth cut along the axial direction and is configured to mesh with the internal gear 14a so as to be able to roll. The ratio of the diameter r of the gear 15 to the inner diameter R of the internal gear 14a is configured to be 1:2.
The eccentric free rotor 16 is formed in a disk shape with a diameter approximately the same as the inner diameter of the through hole 14, and is slidably and rotatably fitted into the through hole 14. The axis of the eccentric free rotor 16 is located at a position that divides the diameter of the eccentric free rotor 16 into four equal parts, with the ratio of the minor axis to the major axis being 1:3.
The gear 15 and the eccentric free rotor 16 are journalled by a crank pin 17 .

The crank arm 18 has a crank pin 17 at its tip end and a crank shaft 19 at its base end.
When the gear 15 rotates once around the internal gear 14a, the crank arm 18 rotates the crankshaft 19 once. The relationship between the gear 15 and the internal gear is the same as in the engine 10 of the first embodiment, so a description thereof will be omitted. The eccentric free rotor 16 is also the same as in the engine 10 of the first embodiment, so a description thereof will be omitted.

17, the cylinder case 20D has a combustion chamber 65 on one side and a cylinder 20d on the other side which is equipped with an intake/exhaust pressure adjusting chamber 66. A piston 11C housed in the cylinder 20d is configured to slide reciprocally between the combustion chamber 65 and the intake/exhaust pressure adjusting chamber 66.
The combustion chamber 65 has an exhaust port 68 with a spark plug 22 and an exhaust port 67 in place.

The spark plug 22 is configured to be energized and ignite, producing a spark, when a combustible gas mixture formed by mixing fuel sprayed from a carburetor or an injector with air in a predetermined ratio is compressed by the piston 11C in the combustion chamber 65. When the spark causes the combustible gas mixture to explode and burn in the combustion chamber, pressure is applied to the piston head 12, causing the piston 11 to move in the cylinder 20d.
The above-mentioned flammable gas mixture is formed by spraying gasoline or alcohol into the air, but is not limited to this and may also be an internal combustion engine that explodes or burns flammable gas extracted from natural gas, hydrogen gas, biomass, etc.

Alternatively, instead of the spark plug 22, an injection device (not shown) that sprays liquid fuel in a mist form may be provided, and a spray port communicating with the injection device may be provided in the combustion chamber 65. In this case, a diesel engine can be constructed in which fuel such as diesel oil is sprayed into high-temperature, high-pressure air compressed by the piston head 12 and burned.

An exhaust port 68 equipped with an exhaust port 67 communicates with the combustion chamber 65 and has an exhaust valve 69 that covers the exhaust port 67. The exhaust valve 69 is configured to periodically open and close the exhaust port 67 using a cam, rocker arm, or the like in response to the rotation of the crankshaft 19, i.e., the movement of the piston 11C. This allows the pressure within the combustion chamber 65 to increase when the exhaust port 67 is closed, and allows the exhaust gas remaining in the cylinder 20d and combustion chamber 65 after explosive combustion to be exhausted and scavenged outside the cylinder 20d and combustion chamber 65 when the exhaust port 67 is open.

The intake/exhaust pressure adjustment chamber 66 is connected to an intake port 70 equipped with an intake port 71. The intake port 70 has a reed valve 72 that restricts the flow of the combustible gas mixture to one direction.

The combustion chamber 65 and the intake/exhaust pressure adjustment chamber 66 are connected by a bypass port 73. The open end 73a of the bypass port 73 on the intake/exhaust pressure adjustment chamber 66 side is located between the intake port 71 of the intake port 70 and the reed valve 72, and the open end 73b on the combustion chamber 65 side is formed at a predetermined position near the bottom dead center L1 of the piston head 12 on the combustion chamber 65 side.

The engine 10I having the above configuration operates as follows, which will be explained with reference to the accompanying drawings.
The engine 10I is a two-stroke engine having an intake/compression stroke and an explosion/exhaust/scavenging stroke.
During the intake and compression strokes, air is first drawn into the intake/exhaust pressure adjusting chamber 66 through the intake port 70 as the piston head 12 on the intake/exhaust pressure adjusting chamber 66 side moves from top dead center L0 to bottom dead center L1. At this time, the combustion chamber 65-side open end 73b of the bypass port 73 is blocked by the piston 11C, so the intake/exhaust pressure adjusting chamber 66 is filled with a combustible mixture gas through the intake port 70. Then, as the piston head 12 on the intake/exhaust pressure adjusting chamber 66 side moves from bottom dead center L1 to top dead center L0, the combustible mixture gas in the intake/exhaust pressure adjusting chamber 66 is compressed. At the moment when the piston 11C shifts and the combustion chamber 65-side open end 73b of the bypass port 73 is opened, the compressed combustible mixture gas flows into the combustion chamber 65 side. The pressure of the inflowing gas scavenges any exhaust gas remaining in the cylinder 20d on the combustion chamber 65 side.
When the piston head 12 on the combustion chamber 65 side moves from the bottom dead center L1 to the top dead center L0, the combustible gas mixture filling the combustion chamber 65 side is compressed.
Next, the explosion, exhaust, and scavenging stroke begins with the explosive combustion of the combustible gas mixture compressed into the combustion chamber 65. After this explosive combustion, in the exhaust and scavenging stroke, the exhaust valve 69 is opened and the exhaust gas is discharged from the exhaust port 67. At this time, negative pressure is generated on the combustion chamber 65 side as the piston head 12 moves from top dead center L0 to bottom dead center L1. Then, the moment the combustion chamber 65-side opening end 72b of the bypass port 73 is opened, the pressurized combustible gas mixture flows in all at once from the intake and exhaust pressure adjusting chamber 66, scavenging the exhaust gas remaining in the cylinder 20d on the combustion chamber 65 side all at once.
In this way, the engine 10I is configured so that the piston head 12 on the intake/exhaust pressure adjusting chamber 66 side takes in and compresses the combustible gas mixture, and then pushes it into the combustion chamber 65 side in one go through the bypass port 73. This makes it possible to increase the intake efficiency and scavenging/exhaust efficiency on the combustion chamber 65 side, thereby improving fuel economy.

An engine 10J shown in FIG. 18 is an in-line four-cylinder engine based on the engine 10I described above.
18, engine 10J is configured with engine 10I as the basic unit, and is arranged in series with a seventh unit 75, an eighth unit 76, a ninth unit 77, and a tenth unit 78 so as to share crankshaft 19. The configurations of each of units 75, 76, 77, and 78 are similar to those of engine 10I, and therefore description thereof will be omitted.
As shown in Figure 18, engine 10J is configured such that the crank arms 18 of the seventh unit 75 and the tenth unit 78, and the crank arms 18 of the eighth unit 76 and the ninth unit 77 are arranged facing each other in opposite directions across the crankshaft 19, and form a crank angle of 180 degrees (π) with respect to each other.

As shown in FIG. 18, the engine 10J is configured such that an intake port 70 branches out to supply a combustible gas mixture to each of the intake ports 71 of the units 75, 76, 77, and 78.
The exhaust gases discharged from the exhaust ports 67 of the units 75, 76, 77, and 78 are collected and discharged through an exhaust port 68.

The engine 10J having the above-described configuration operates as follows, which will be explained below with reference to the accompanying drawings.
The crank arms 18 of the seventh unit 75 and the tenth unit 78, and the crank arms 18 of the eighth unit 76 and the ninth unit 77 are arranged facing each other in opposite directions across the crankshaft 19, and are configured to form a crank angle of 180 degrees (π) with respect to each other.
18 , when the intake/exhaust pressure adjusting chamber 66 side piston heads 12 of the seventh unit 75 and the tenth unit 78 are located at top dead center L0 and the combustion chamber 65 side piston heads 12 are located at bottom dead center L1, the intake/exhaust pressure adjusting chamber 66 side piston heads 12 of the eighth unit 76 and the ninth unit 77 are located at bottom dead center L1 and the combustion chamber 65 side piston heads 12 are located at top dead center L0. In this way, the pistons 11C of the set consisting of the seventh unit 75 and the tenth unit 78 and the set consisting of the eighth unit 76 and the ninth unit 77 perform linear reciprocating motions alternately in opposite directions, whereby the pistons 11C of the set consisting of the seventh unit 75 and the tenth unit 78 and the pistons 11C of the set consisting of the eighth unit 76 and the ninth unit 77 perform linear reciprocating motions alternately in opposite directions. The operation of each unit is similar to that of the engine 10I, and therefore a detailed description thereof will be omitted.
In this way, the engine 10J can be configured so that the explosion stroke is always performed in one of the cylinders 20d in the pair consisting of the seventh unit 75 and the tenth unit 78 and the pair consisting of the eighth unit 76 and the ninth unit 77. Therefore, explosions at equal intervals can be performed throughout the entire engine 10J.
Furthermore, because the pistons 11C of the set consisting of the seventh unit 75 and the tenth unit 78 and the set consisting of the eighth unit 76 and the ninth unit 77 alternately perform linear reciprocating motion in opposite directions for each set, vibrations caused by the movement of the pistons 11C can be canceled out, the side pressure generated when the pistons 11C press against the inner wall of the cylinder 20d can be suppressed, and friction loss when the pistons 11C slide along the inner wall of the cylinder 20d can be reduced. As a result, the generation of vibrations or noises caused by contact between the pistons 11C and the cylinder 20d can be suppressed.

While the above example illustrates an in-line four-cylinder engine, the seventh unit 75 through the tenth unit 78 may be arranged in a V-shape so that the combustion chambers are alternately positioned. Furthermore, the number of cylinders is not limited to this, and a multi-cylinder engine may be configured by adding or removing units from the basic configuration of engine 10I. In this case, the phase difference between each unit may be set to a predetermined angle, such as 120 degrees (4π/3), 72 degrees (π/5), 60 degrees (π/3), or 45 degrees (π/4), preferably so that the crank arms 18 of each unit are balanced around the crankshaft 19. This allows vibrations, such as primary vibrations, even vibrations, and secondary vibrations, to be canceled out between the units.
In either case, a balance weight may be attached to the crankshaft 19 to suppress vibration.
In each engine configured as described above, the length of the crank arm 18 revolving around the crankshaft 19 can be made shorter than the length of the crank arm in a conventional engine, allowing for a reduction in the weight of the balance weight that cancels out the moment of inertia revolving around the crankshaft 19. Furthermore, in a conventional connecting rod, whose tip end reciprocates and whose base end rotates, vibrations due to the reciprocating motion and vibrations due to the rotational motion occur. However, the engine according to this embodiment, which does not include such a connecting rod, can eliminate the vibration components and causes of vibration caused by the operation of the connecting rod. This makes it possible to eliminate the effects of connecting rod operation among the primary vibration, even-force vibration, secondary vibration, and other vibrations that occur in the engine.

In the engine according to this embodiment, a through hole 14 with an internal gear 14a is formed at the center of the peripheral wall of a piston that is a substantially cylindrical body with piston heads disposed on both the left and right ends, and a gear 15 journaled by a crank pin 17 rolls on the internal gear 14a. This allows the reciprocating motion of the piston to be converted into the rotational motion of the gear that rolls along the internal gear 15a, and further converted into the rotational motion of the crankshaft 19 via a crank arm 18 that is rotated by the gear.
Furthermore, because the piston according to this embodiment reciprocates linearly within the cylinder, when the piston reciprocates within the cylinder, the side pressure that presses the side wall of the piston against the inner wall of the cylinder can be suppressed, preventing the piston from contacting the inner wall of the cylinder unevenly and reducing friction loss between the piston and the cylinder. This suppresses heat generation in the cylinder, improving the heat conversion efficiency of the engine, thereby improving the output characteristics and fuel efficiency of each engine.

Furthermore, with the engine according to this embodiment, the amplitude of the reciprocating motion of the piston in the cylinder and the relationship between the bore and stroke can be freely designed without being limited by the length of the connecting rod or crank arm as in conventional engines, which allows the engine to be made compact and lightweight, for example.
Additionally, the engine according to this embodiment is configured so that the piston reciprocates linearly within the cylinder. In a conventional engine crankshaft, the connecting rod swings, generating a lateral force on the piston relative to the cylinder, causing the piston to strike the inner wall of the cylinder, resulting in a phenomenon known as piston slap. To prevent this, a piston skirt is formed below the piston. However, in the engine according to this embodiment, the piston slap phenomenon is unlikely to occur due to its configuration, so the length of the piston skirt can be minimized, allowing for a shorter piston. Furthermore, the clearance between the piston and cylinder is further narrowed, piston ring play is eliminated, and the length of the piston crown can be shortened. This, combined with the shorter piston skirt, allows for a more compact piston design.

The engine of this embodiment eliminates the need for a connecting rod and instead features a linear piston reciprocating motion. This allows for a new bore/stroke design not possible with conventional engines, allowing for a longer stroke length for a larger bore, improving combustion efficiency within the combustion chamber and significantly reducing heat loss. In conventional engines, the piston collides with the inner wall of the cylinder as the crank arm and connecting rod move, creating stress between the connecting rod and crank arm, resulting in significant heat generation not only from the explosion of the combustible mixture but also from the movement of the engine's structures. However, the engine of this embodiment significantly reduces friction loss between the piston and the cylinder caused by the piston's collision and vibration, and also reduces the load on the crank arm. This reduces unnecessary heat generation within the engine itself due to friction, improving combustion efficiency and significantly reducing heat loss.

The engine according to this embodiment is not limited to being installed in automobiles, but can also be applied to ships, aircraft, locomotives, and other vehicles equipped with internal combustion engines, as well as pumps, generators, and other vehicles equipped with internal combustion engines. In any case, the above-mentioned effects can be expected, leading to not only improved fuel consumption but also a significant reduction in the burden on the environment.

10, 10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 10I, 10J...Engine,
14...through hole, 14a...internal gear, 15...gear, 16...eccentric free rotor, 17...crank pin, 18...crank arm, 19...crank shaft.

Claims (13)

a substantially cylindrical piston having piston heads on both left and right end surfaces;
a through hole having a predetermined inner diameter formed in a radial direction of the piston at the center of a peripheral wall portion of the piston;
an internal gear formed along an inner wall of the through hole;
a gear that meshes with the internal gear;
a substantially rod-shaped crank arm having a crank pin at its tip for supporting the gear;
a crankshaft fixed to a base end of the crank arm;
a disk-shaped eccentric free rotor having substantially the same diameter as the inner diameter of the through hole, rotatably fitted into the through hole, and journaled together with the gear by the crank pin;
a cylinder case including a cylindrical cylinder into which the piston is inserted, the piston heads connecting opposing combustion chambers to both ends of the cylinder,
When the piston reciprocates left and right in the cylinder,
the gear meshed with the internal gear that reciprocates following the piston rotates in a predetermined direction within the through hole,
The crank arm rotates the crankshaft in a predetermined direction via the crank pin that supports the gear, and
The eccentric free rotor rotates in the through hole in a direction opposite to a rotation direction of the crank arm,
a crankcase is provided so as to surround the through-hole that contains at least the crankshaft and the crank arm;
an intake port having an intake port arranged along the axial direction of the crankshaft of the crankcase, and an exhaust port having an exhaust port arranged at a predetermined position on a side wall portion of the cylinder,
a bypass port that communicates the crankcase with the cylinder and has a cylinder-side open end that is located on the opposite side of the combustion chamber from the exhaust port;
The eccentric free rotor is provided with a notch formed by cutting out an arc-shaped portion at a predetermined position on the periphery of the rotor surface,
The intake port and the notch are disposed opposite to each other,
an engine configured such that, as the eccentric free rotor rotates, when the intake port and the cutout portion overlap, the intake port is opened, and when the intake port and the peripheral portion overlap, the intake port is closed . The engine described in claim 1, characterized in that the diameter of the piston near the center of the peripheral wall is smaller than the diameter of the piston skirts formed adjacent to the piston head on both left and right end faces. The engine described in claim 1, characterized in that the diameter of the piston near the center of the peripheral wall is larger than the diameter of the piston skirts formed on both left and right end faces and connected to the piston head, or the diameter of the piston skirts gradually increases from the side opposite the piston head toward the center of the peripheral wall, forming the peripheral wall near the center in an approximately spherical shape. The piston skirts formed on both left and right end surfaces of the piston head are cut out on the opposite side of the piston head,
2. The engine according to claim 1, wherein a flat portion having the through hole is formed near the center of the peripheral wall portion of the piston. a spark plug having an electrode disposed at a predetermined position in the combustion chamber;
2. The engine according to claim 1, wherein when the piston head compresses a combustible gas mixture formed by mixing air and atomized fuel in a predetermined ratio in the combustion chamber, the combustible gas mixture is ignited by a spark generated from the electrode. providing an injection device having a spray nozzle disposed at a predetermined position in the combustion chamber;
2. The engine according to claim 1, wherein when the piston head rapidly compresses air in the combustion chamber to form high-temperature, high-pressure air, the injector sprays a predetermined fuel in the form of a mist from the spray nozzle, and the fuel is combusted with the high-temperature, high-pressure air. a piston comprising a pair of generally cylindrical small diameter portions and a generally cylindrical large diameter portion having a diameter larger than the small diameter portions and sandwiched between the small diameter portions, wherein a piston head and a piston skirt connected to the piston head are formed on an end surface of the small diameter portion opposite the large diameter portions, and a through hole having a predetermined inner diameter is formed in the center of the large diameter portion along the radial direction;
an internal gear formed along an inner wall of the through hole;
a gear that meshes with the internal gear;
a substantially rod-shaped crank arm having a crank pin at its tip for supporting the gear;
a crankshaft fixed to a base end of the crank arm;
a disk-shaped eccentric free rotor having substantially the same diameter as the inner diameter of the through hole, rotatably fitted into the through hole, and journaled together with the gear by the crank pin;
a pair of cylindrical cylinders into which the small diameter portions are inserted, and a cylinder case connected to the cylinders and including a housing into which the large diameter portions are fitted, the cylinder case having a combustion chamber at the end of the cylinder opposite the housing, the piston head facing the combustion chamber;
When the small diameter portion reciprocates within the cylinder,
The large diameter portion reciprocates in response to the small diameter portion, and the gear meshed with the internal gear rotates in a predetermined direction within the through hole,
The crank arm rotates the crankshaft in a predetermined direction via the crank pin that supports the gear, and
The engine is characterized in that the eccentric free rotor rotates within the through hole in a direction opposite to the rotation direction of the crank arm. a spark plug having an electrode disposed at a predetermined position in the combustion chamber;
8. The engine according to claim 7, wherein when the piston head compresses a combustible gas mixture formed by mixing air and atomized fuel in a predetermined ratio in the combustion chamber, the combustible gas mixture is ignited by a spark generated from the electrode. an intake port having an intake port for supplying the combustible gas mixture to the combustion chamber, and an exhaust port having an exhaust port for discharging exhaust gas from the combustion chamber after the combustible gas mixture has been burned;
9. An engine according to claim 8, wherein the intake port and the exhaust port are provided at predetermined positions in the combustion chamber. an intake port having an intake port for supplying the combustible gas mixture to the combustion chamber, and an exhaust port having an exhaust port for discharging exhaust gas from the combustion chamber after the combustible gas mixture has been burned;
The intake port is provided at a predetermined position of the cylinder, and the exhaust port is provided at a predetermined position of the combustion chamber,
9. The engine according to claim 8, wherein the intake port is provided with a piston reed valve for restricting the flow of the combustible gas mixture toward the inside of the cylinder in one direction. providing an injection device having a spray nozzle disposed at a predetermined position in the combustion chamber;
8. The engine according to claim 7, wherein when the piston head rapidly compresses air in the combustion chamber to form high-temperature, high-pressure air, the injector sprays a predetermined fuel in the form of a mist from the spray nozzle, and the fuel is combusted with the high-temperature, high-pressure air. an intake port having an intake port for supplying the air to the combustion chamber, and an exhaust port having an exhaust port for discharging exhaust gas from the combustion chamber after the fuel is burned;
12. The engine according to claim 11, wherein the intake port and the exhaust port are provided at predetermined positions in the combustion chamber. an intake port having an intake port for supplying the air to the combustion chamber, and an exhaust port having an exhaust port for discharging exhaust gas from the combustion chamber after the fuel is burned;
The intake port is provided at a predetermined position of the cylinder, and the exhaust port is provided at a predetermined position of the combustion chamber,
12. The engine according to claim 11, wherein the intake port is provided with a piston reed valve that restricts the air to flow in one direction toward the inside of the cylinder.