JPH0534516B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel injection device for a compression ignition engine.

[Conventional technology]

The fuel injection method for compression ignition engines is the air injection method, which injects fuel together with compressed air.
There are two types: the injection type) and the airless injection type, which injects only highly compressed fuel, but in recent years, the airless injection type has been adopted in most engines except in special cases. ing.

[Problem that the invention seeks to solve]

The above-mentioned airless fuel injection method has come to be widely used because it has less power loss and no failure than the air injection method.

However, in order to improve fuel atomization and combustion during fuel injection, high-pressure injection is required, and a complicated and highly accurate injection pump and injection nozzle are required, resulting in high costs. Since the fuel is atomized when injected into the cylinder, the latent heat of vaporization is taken away, making it difficult to start the engine unless the compression ratio is high. Adversely affect.

In addition, since the injection nozzle is exposed to combustion gas, carbon sticking is likely to occur, and to prevent this, it is necessary to incorporate an injection port sealing valve, which complicates the structure and increases processing and assembly costs. was.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel injection device for an engine with a simple structure and low cost, which has good fuel atomization performance, can easily achieve a good combustion state, and can easily perform cold starting. It is said that

[Means for solving problems]

A feature of the present invention is that a fuel injection device for a compression ignition engine is configured as follows.

A casing having a fuel injection hole at one end and forming a plunger chamber inside, a plunger that is slidable within the casing, an air intake passage connected to the plunger chamber, and a fuel inlet connected to the passage. In preparation, the plunger is returned in a direction away from the fuel injection hole in synchronization with the rotation of the engine, and as air is sucked from the passage into the plunger chamber, fuel is atomized and mixed from the fuel inlet into the intake air. a first driving means for sucking air into the plunger chamber while driving the returned plunger to advance toward the fuel injection hole side to compress the air-fuel mixture in the plunger chamber;
The fuel injection device includes a second driving means for injecting fuel into the compressed air in the cylinder from the injection hole, and a plunger pushing-in maintaining means for maintaining the pushed-in state in which the plunger is advanced to the terminal position until the intake stroke of the cylinder.

[Effect]

(i) If configured as in the present invention, as shown in FIG. 3, for example, the plunger 32 is driven back to the left in the drawing by the first driving means, and the negative pressure generated in the plunger chamber 33 causes air intake Air is rapidly drawn into the plunger chamber 33 through the passage 36 .

As a result, the fuel from the fuel inlet (28 in Figure 1) enters the passage 36 and is mixed with the intake air to atomize the fuel, and the atomized fuel and air are The mixture enters the plunger chamber 33 and forms an air-fuel mixture within the plunger chamber 33.

(ii) When the air-fuel mixture is sucked into the plunger chamber as described above, the plunger 32 is moved by the second driving means.
is driven forward to the right side of the paper.

As a result, the pressure of the air-fuel mixture in the plunger chamber 33 is increased by the plunger 32, and the temperature is increased by the heat of compression. Then, the above-mentioned high-pressure, high-temperature air-fuel mixture is directly injected from the fuel injection hole 18 into the compressed and high-temperature air in the cylinder.

(iii) Furthermore, since the plunger that injects the air-fuel mixture as described above is maintained at its advanced position by the plunger pushing and maintaining means until the intake stroke of the cylinder,
During the subsequent explosion, expansion, and exhaust strokes, the combustion gas is prevented from flowing into the plunger chamber by the plunger in the advanced position.

〔Effect of the invention〕

The fuel injection device for an engine according to the present invention is constructed and operates as described above, and therefore brings about the following effects.

Since fuel is rapidly drawn into the plunger chamber together with air, good fuel atomization is achieved without requiring high pressure.

Since the air-fuel mixture in the plunger chamber is compressed to a high pressure and high temperature, the latent heat of vaporization due to fuel atomization can be compensated for in advance during fuel injection, and a reliable and smooth start can be performed without particularly increasing the compression ratio.

Since the air-fuel mixture is compressed at high pressure and high temperature in the plunger chamber and injected into the cylinder, it is easier to achieve good combustion conditions, reducing diesel nok and smoke.

It does not require complicated and highly accurate equipment such as conventional injection pumps and injection nozzles, and can be implemented at low cost.

Even without a sealing valve for the fuel injection port, there is no inflow of combustion gas into the plunger chamber, and carbon stagnation does not occur.

Since there is no need to use a sealing valve for the fuel injection port, it is structurally simple and can be implemented at low cost.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on illustrative drawings.

FIG. 1 shows an overall longitudinal side view of the engine, and FIG. 2 shows its longitudinal front view. The main body case 1 of this engine has a two-part structure in which a front case 1a, which is the output side, and a rear case 1b, which is the head side, are bolted together.
A cylinder case 3 is rotatably supported horizontally via a bearing 2.

The cylinder case 3 is formed of front and rear cylinder shaft cases 4 and 5 supported by a bearing 2, and an intermediate case 6 sandwiched and connected between them. A penetrating cylinder 7 having orthogonal axes is formed.

A pair of pistons 8 are fitted into the cylinder 7 so as to face each other, and a solid or hollow steel ball 9 is rotatably attached to the skirt portion of the piston 8 via a bearing metal 10 having a partially spherical shell shape. , is supported by a stopper ring 11 to prevent it from coming off.

A cam plate 12 is fastened together between the front and rear cases 1a and 1b of the main body case 1, and an oblong cam hole 13 formed in the center of the cam plate 12.
A steel ball 9 of the piston 8 is inscribed in the piston 8, so that the piston 8 reciprocates twice for each rotation of the cylinder casing 3.

The rear end surface of the cylinder 7 is configured to be in sliding contact with the head portion 14 formed at the center of the rear case 1b in the direction of the rotation axis P.
One intake/exhaust port 15 eccentric to the rotation axis P is formed. As shown in FIG.
4, the exhaust hole 16, the intake hole 1
7 and a fuel injection hole 18 are provided, and as the cylinder case 3 rotates, the intake/exhaust port 15 connects to the exhaust hole 1.
6. The cylinder case 3 is configured to continuously rotate in a constant direction A by communicating with the intake hole 17 and the fuel injection hole 18 at appropriate timing to perform four cycles of exhaust, intake, compression, and explosion expansion.

As shown in FIG. 1, the rotational output of this cylinder 3 is transmitted to
Alternatively, it can be taken out from a PTO shaft (not shown) attached to the spline hole 20.

A fan 21 is attached to the shaft end of the cylinder shaft case 4 together with the output pulley 19, and a fan 21 is attached to the shaft end of the cylinder shaft case 4. After passing through a cooling air passage 24 formed in the cylindrical shaft case 4, the air is suctioned and discharged from an exhaust port 25 provided at the front end circumference of the cylinder shaft case 4, thereby cooling the head portion 14 and the cylinder 7.

As shown in FIGS. 1, 3, and 4, a muffler 2 that communicates with the exhaust hole 16 is provided on the outside of the head portion 14.
6. Air cleaners 27 communicating with the intake holes 17 are connected respectively. A fuel inlet 28 is provided which is piped to a fuel tank (not shown), and the intake hole 17 and fuel inlet 28 are connected to a fuel injection device to be described below.

Next, the fuel injection device for this engine will be explained.

As shown in FIGS. 3 and 1, a plunger type casing 29 is embedded and fixed inside the head portion 14, and a fuel injection hole 18 is formed at the tip thereof. Inside the casing 29 is the Rotzker arm 3.
A plunger 32, which is driven forward and backward by a spring 31 and urged toward the return operation side by a spring 31, is fitted inside the plunger 32. A small hole 34 that opens when the plunger 32 retreats is formed in the periphery of the plunger chamber 33 formed in the casing 29.
4 communicates with the intake hole 17 via an annular groove 35 and an air intake passage 36.

A fuel control valve 37 whose opening degree can be adjusted is provided in the passage 36.
is provided. The fuel control valve 37 is located on the rotation axis P of the cylinder case 3, and includes a fixed sleeve 38 embedded in the head portion 14 and a tapered needle that moves back and forth along the rotation axis P. It consists of 39. As a result, the fuel inlet 28 is connected to the flow path 40, the annular groove 41, and the communication hole 4.
2 into the sleeve 38, and the sleeve 38 and the needle 3 are connected by moving the needle 39 back and forth.
9 = By adjusting the opening degree, the passage 3
The amount of fuel flowing into the fuel tank 6 is adjusted.

The needle 39 is configured to be controlled to advance and retreat by a mechanical governor. This governor consists of a governor spring 43 that presses the needle 39 in the direction of increasing the opening degree of the fuel control valve 37, and a governor weight 44 that generates a governor force that presses the needle 39 in the direction of decreasing the opening degree. The speed can be set by moving the spring receiving rod 45, which receives the rear end of the spring receiving rod 43, forward and backward with a speed regulating arm 46. The speed regulating arm 46 is linked to a speed regulating lever (not shown) via a release wire 47.

The governor weight 44 has a recess 48 formed eccentrically with respect to the rotation axis P at the rear end of the cylinder case 3.
It is housed in the cylinder case 3 and is swingably supported by a bracket 49 screwed and fixed to the cylinder case 3. Then, the arm 44a provided on the governor weight 44 is brought into contact with the tip of the push rod 39a of the needle 39, and the governor weight 44 is brought into contact with the tip of the push rod 39a of the needle 39.
The centrifugal force (governor force) of 4 is the needle 39
It is becoming possible to convey this to people.

Rocker arm 30 for driving plunger 32
is supported by a ball fulcrum 51 provided on the head cover 50, and one end of the rocker arm 30 is connected to one end of a bell crank 53 via a push rod 52. The other end of the bell crank 53 is in contact with the outer periphery of a rotary cam 54 formed integrally with the cylinder shaft case 5 via a ball 55, and the plunger 32 is driven back and forth once for each rotation of the cylinder case 3. It is becoming more and more common. The tip of the rocker arm 30 on the plunger 32 side is engaged in a recess 57 of an abutment piece 56 that is driven and fixed to the rear end of the plunger 32, thereby preventing the rocker arm 30 from swinging laterally.

The engine according to the present invention is constructed as described above, and its operation will be explained next.

The cylinder case 3 rotates clockwise in FIG. 5, and after the intake/exhaust port 15 of the cylinder case 3 overlaps the exhaust hole 16 and both pistons 8 move toward each other and exhaust is performed, Air is taken into the cylinder 7 by the pistons 8 moving away from each other due to centrifugal force while the intake/exhaust port 15 overlaps the intake hole 17, and the cylinder 7 subsequently enters a compression stroke.

Then, the plunger 32 is driven backward and forward only once until this compression stroke is completed. In this case, as shown in FIG. 3, air is rapidly sucked into the plunger chamber 33 by the spring 31 returning the plunger 32 to the left in the drawing, and the negative pressure generated in the passage 36 at this time causes Fuel is sucked from the fuel control valve 37 and mixed with the air in the passage 36 while being atomized. The air-fuel mixture thus formed passes through the small hole 34 into the plunger chamber 3.
3, and at this time, the atomization of the fuel is further promoted (the above corresponds to the first driving means).

As the plunger 32 moves to the right in the drawing, a certain amount of the air-fuel mixture in the plunger chamber 33 is compressed and becomes a high-pressure, high-temperature air-fuel mixture. After the compression of this air-fuel mixture is completed, the intake/exhaust port 15 of the cylinder case 3 that has completed the compression stroke begins to overlap the fuel injection hole 18, and the high-pressure, high-temperature air-fuel mixture in the plunger chamber 33 enters the high-temperature compressed air in the cylinder 7. is ejected and moves to the explosion stroke (the above corresponds to the second driving means).

During this explosion stroke and the subsequent exhaust stroke, the plunger 32 is held at the final position of advancement, and the rotating cam 54 is maintained so that combustion gas is prevented from flowing into the plunger chamber 33.
The outer circumferential profile of the plunger is set and exposed (the above corresponds to the means for maintaining plunger depression). Then, following the explosion stroke, the engine moves to the exhaust stroke, and this cycle is repeated thereafter.

In order to improve airtightness at the sliding contact area between the intake and exhaust ports 15 of the cylinder case 3 and the head portion 14 when the cylinder 7 is in the compression stroke and the explosion stroke, the intake and exhaust ports are installed as shown in FIG. A thrust ring 59 with a seal ring 58 is fitted into the stepped portion of the mouth edge of No. 15. As a result, the thrust ring 59 is brought into close contact with the head portion 14 by applying the internal pressure of the cylinder 7 to the front space 60 of the thrust ring 59.

An annular groove 61 is formed on the end surface of the head portion 14 to collect gas leaking from the intake and exhaust ports 15 of the cylinder case 3. A part of this annular groove 61 passes through a passage 62 to the intake hole. 17. Thereby, the gas collected in the annular groove 61 is returned to the cylinder 7 together with the intake air.

Furthermore, lubricating oil is stored inside the main body case 1.
Each sliding and rolling part is lubricated.

[Another Embodiment] Both the return and advance driving of the plunger 32 may be performed using the rotating cam 54, rocker arm 30, etc. shown in FIG. 1.

The plunger 32 may be driven forward by a solenoid. In this case, plunger 3
2 can be maintained until the intake stroke by keeping the solenoid energized.

The fuel injection device for an engine of the present invention can be used not only for an engine in which the cylinder case 3 rotates as described above, but also as a fuel injection device for a general compression ignition type engine with intake and exhaust valves. .

[Brief explanation of the drawing]

FIG. 1 is a longitudinal side view of the entire engine according to the present invention, FIG. 2 is a longitudinal front view of the vicinity of the cylinder and piston, FIG. 3 is an enlarged sectional view of the vicinity of the fuel injection device in the head, and FIG. 1 is a front view of the head side viewed from the left side of the page, and FIG. 5 is a longitudinal sectional front view of the vicinity of the head portion of FIG. 1 viewed from the right side of the page. 7... Cylinder, 18... Fuel injection hole, 28...
... Fuel inlet, 29 ... Casing, 31 ... Spring, 32 ... Plunger, 33 ... Plunger chamber, 36 ... Air intake passage, 54 ... Rotating cam.

Claims (1)

[Claims] 1. A casing 29 having a fuel injection hole 18 at one end and forming a plunger chamber 33 inside, and a plunger 32 slidable within the casing 29.
, an air intake passage 36 connected to the plunger chamber 33 , and a fuel inlet 28 connected to the passage 36 , the plunger 32 is synchronized with the rotation of the engine.
is driven back in the direction away from the fuel injection hole 18, and as air is sucked into the plunger chamber 33 from the passage 36, the fuel is atomized and mixed into the intake air from the fuel inlet 28, while the plunger a first driving means for causing suction into the chamber 33 ; and a first driving means for driving the returned plunger 32 to advance toward the fuel injection hole 18 side to cause the plunger chamber 33 to be sucked into the chamber 33 .
a second driving means for compressing the air-fuel mixture in the cylinder 7 and injecting it from the fuel injection hole 18 into the compressed air in the cylinder 7; A fuel injection device for an engine, comprising means for maintaining plunger depression. 2. The engine fuel injection device according to claim 1, wherein the first driving means for the plunger 32 is a spring 31. 3. The fuel injection device for an engine according to claim 1, wherein the first driving means for the plunger 32 is a rotating cam 54 driven in synchronization with the rotation of the engine. 4. Fuel injection for an engine according to any one of claims 1 to 3, wherein the second driving means for the plunger 32 is a rotary cam 54 driven in synchronization with the rotation of the engine. Device. 5. The fuel injection device for an engine according to any one of claims 1 to 3, wherein the second driving means for the plunger 32 is a solenoid. 6. Fuel injection for an engine according to claim 4, wherein the plunger pushing maintaining means is provided in the rotating cam 54 by setting a profile of the rotating cam 54 driven in synchronization with the rotation of the engine. Device. 7. The engine fuel injection device according to claim 5, wherein the plunger pushing and maintaining means holds the solenoid on the advancing side of the plunger 32.