JP6455184B2 - Engine intake port structure - Google Patents

Description

  The present invention relates to an engine intake port structure that enables good combustion in a combustion chamber.

  Conventionally, a tumble flow (vertical vortex) that is a swirl flow that flows along the axial direction of the cylinder bore and a swirl flow that is a swirl flow that flows along the circumferential direction of the inner peripheral surface of the cylinder bore (horizontal vortex) in the combustion chamber of the engine. Various techniques for generating vortices are known.

  As a technique for generating a tumble flow, for example, there is a technique for generating a tumble flow by changing the degree of shielding in the intake port using an intake flow control valve provided in the intake port (see, for example, Patent Document 1). ). In addition, there is a type that generates a tumble flow by ejecting air downward from a nozzle provided in an intake port along a wall surface of a valve throat portion (see, for example, Patent Document 2).

  Furthermore, in order to strengthen the tumble flow, there is a technique of reducing the inner diameter of the intake port and providing an edge portion on the inner surface of the intake port on the side far from the axis of the cylinder bore. By providing the edge portion, the cross-sectional area of the flow path is reduced, and the tumble flow can be strengthened by increasing the flow velocity (see, for example, Patent Document 3).

JP 2007-32560 A JP 2013-122188 A Japanese Unexamined Patent Publication No. 2007-46457 (see page 3, paragraph 0010, page 8, FIG. 6)

  As described above, when generating a tumble flow of intake air in the fuel chamber, there is a demand for further strengthening the tumble flow in order to ensure good combustion. However, the addition of various valve devices and nozzles to enhance the tumble flow is limited because it increases the complexity and cost of the device.

  Further, according to the technique of Patent Document 3, since the intake passage is bent around the edge portion in the intake port, it is assumed that the flow coefficient decreases and conversely the tumble flow weakens.

  Accordingly, an object of the present invention is to enhance the tumble flow in the fuel chamber without complicating the structure.

  In order to solve the above problems, the present invention includes an intake port connected to an engine combustion chamber and opened and closed by an intake valve, and an annular seat ring provided in a region of the intake port facing the combustion chamber. The seat ring includes a valve abutting portion that extends from the back side toward the combustion chamber side so that the intake valve abuts, and the valve ring that is provided on the far side from the valve abutting portion. A throat portion that expands toward the contact portion side, and the center line of the intake valve is arranged eccentrically toward the axis of the cylinder bore with respect to the center line of the flow path of the seat ring, and the throat portion includes a cylinder bore The intake port structure of the engine is adopted in which the front end side closer to the cylinder bore axis is deeper toward the back side than the rear end side far from the axis.

  The throat portion is formed on the inner surface of the seat ring or the inner surface of the intake port by a throat cutter that rotates around the center line of the intake valve, and the valve contact portion is formed on the intake valve. It is possible to adopt a configuration in which the inner surface of the seat ring is processed by a sheet cutter that rotates around a center line.

  In addition, the valve abutting portion may be configured such that the depth is the same between the front end side and the rear end side.

  And an intake port connected to the combustion chamber of the engine and opened and closed by an intake valve, and an annular seat ring provided in a region of the intake port facing the combustion chamber, the seat ring being in contact with the intake valve In this way, a valve contact portion that extends from the back side toward the combustion chamber side, and a throat portion that is provided on the back side from the valve contact portion and extends from the back side toward the valve contact portion side. In the method of manufacturing an intake port of an engine, the center line of the intake valve is eccentrically arranged near the axis of the cylinder bore with respect to the center line of the flow path of the seat ring, and the throat portion is disposed on the intake valve Machining the inner surface of the seat ring or the inner surface of the intake port with a throat cutter that rotates about the center line of the Adopting a method of manufacturing the intake port of the engine to process the inner surface of the seat ring by a sheet cutter to rotate about a line.

  According to the present invention, a seat ring is provided on a deeper side than the valve contact portion, the valve contact portion expanding from the back side toward the combustion chamber side so that the intake valve contacts, and In the configuration including the throat portion that expands toward the valve contact portion side, the center line of the intake valve is arranged eccentrically with respect to the axis of the cylinder bore with respect to the center line of the flow path of the seat ring. The side, that is, the throat portion near the axial center of the cylinder bore is easily secured.

  In other words, the throat portion can be formed deeper on the front end side closer to the cylinder bore axis than on the rear end side far from the cylinder bore axis, and the intake air can be smoothly drawn on the front end side. By guiding to the combustion chamber and suppressing the separation of the intake air from the inner surface of the intake port on the rear end side, the tumble ratio, that is, the rotational speed of the tumble flow during one reciprocation of the piston can be improved. For this reason, the tumble flow in the fuel chamber can be enhanced without complicating the structure.

  In addition, since the center line of the intake valve is deviated from the center line of the flow path of the seat ring toward the axis of the cylinder bore, the throat portion is secured while securing the throat portion deep in the part near the axis of the cylinder bore. It is also possible to expect an effect that the machining of the valve part and the valve contact part can be performed coaxially with the center line of the valve.

It is a principal part enlarged view of the intake port which shows embodiment of this invention. It is a principal part enlarged view which shows the same embodiment. (A) (b) is explanatory drawing which shows the processing method of an intake port. (A) is a longitudinal sectional view schematically showing the inside of the engine, and (b) and (c) are detailed views of the intake port. It is a graph which shows the effect of this invention. It is a principal part enlarged view of the intake port which shows other embodiment.

  Embodiments of the present invention will be described with reference to the drawings. FIGS. 1 and 2 are enlarged views of the main part showing the vicinity of the intake port 5 of the engine of this embodiment. FIG. 3 is an explanatory view showing a method of processing the intake port 5.

  The arrangement of the engine combustion chamber 3 and the shape of the intake port 5 are shown in FIG. The engine of this embodiment is a diesel engine for automobiles. A piston 2 is accommodated in the cylinder 1 of the engine. A combustion chamber 3 is formed by the inner peripheral surface of the cylinder 1, the upper surface of the piston 2, and the like. An intake port 5 for sending intake air into the combustion chamber 3 of each cylinder, an exhaust port 7 drawn out from the combustion chamber 3, a fuel injection device 9 for injecting fuel into the combustion chamber 3, and the like are provided.

  In these drawings, members and means directly related to the present invention are mainly shown, and other members and the like are not shown. Although only one cylinder 1 is shown in the drawing, the engine may be a single cylinder or a multi-cylinder having a plurality of cylinders.

  In this embodiment, as shown in FIG. 4C, the intake port 5 is branched into two passages before the combustion chamber 3. Although not shown, the exhaust port 7 also branches into two passages before the combustion chamber 3.

  An intake valve hole 5 a that is an opening to each combustion port 3 of each intake port 5 is opened and closed by an intake valve 6. Further, the exhaust valve hole 7 a that is an opening to each combustion port 3 of each exhaust port 7 is opened and closed by the exhaust valve 8. At this time, the intake valve 6 and the exhaust valve 8 are brought into contact with and separated from an annular seat ring 20 provided in a region facing the combustion chamber 3 of the intake port 5 and the exhaust port 7 respectively.

  The intake valve 6 and the exhaust valve 8 open and close the intake valve hole 5a and the exhaust valve hole 7a at a predetermined timing by the rotation of a camshaft provided on the cylinder head 4 side. The shaft portions of the intake valve 6 and the exhaust valve 8 are drawn out from the shaft insertion portions opened on the inner surfaces of the intake port 5 and the exhaust port 7 to the camshaft side in the cylinder head 4. As shown in FIG. 4B, the shaft insertion portion 5b of the intake port 5 is opened to the bent portion 5c located upstream of the intake valve hole 5a in the intake port 5 or to the upstream side of the bent portion 5c. doing.

  As shown in FIGS. 1 and 2, the seat ring 20 includes a valve contact portion 21 that expands from the back side toward the combustion chamber side so that the intake valve 6 contacts, and a deeper side than the valve contact portion 21. And a throat portion 22 that is provided on the portion side and expands from the back side toward the valve contact portion 21 side.

  The center line q2 of the intake valve 6 is arranged near the axis x of the cylinder bore by a distance w with respect to the center line q1 of the flow path of the seat ring 20, that is, eccentric to the front end side of the intake valve hole 5a. .

  The throat portion 22 is processed as follows. It is assumed that the seat ring 20 before processing is press-fitted in advance to a portion of the intake port 5 facing the combustion chamber 3 and is fixed to the intake port 5.

  As shown in FIG. 3 (a), the throat cutter A is made to enter a predetermined amount into the intake port 5 along the axial center coinciding with the center line q2 of the intake valve 6. The inner surface of the seat ring 20 is shaved by rotating the throat cutter A around the center line q2. Depending on the specifications, the throat portion 22 may be continuously processed from the inner surface of the seat ring 20 to the inner surface of the intake port 5. By processing the throat cutter A, a throat portion 22 made of a conical surface or a spherical surface is formed on the inner surface of the seat ring 20 or on the inner surface of the seat ring 20 and the inner surface of the intake port 5.

  The valve contact portion 21 is processed as follows. After removing the throat cutter A, as shown in FIG. 3B, the seat cutter B is made to enter a predetermined amount into the seat ring 20 along the axis that coincides with the center line q2 of the intake valve 6. The inner surface of the seat ring 20 is shaved by rotating the sheet cutter B around the center line q2. By processing the seat cutter B, a valve contact portion 21 made of a conical surface or a spherical surface is formed on the inner surface of the seat ring 20.

  The throat portion 22 may be processed before the valve contact portion 21, or the valve contact portion 21 may be processed before the throat portion 22.

  The symbol r1 in the figure indicates the radius of the flow path of the seat ring 20. Reference numeral o1 indicates the center of the seat ring (the center of the flow path of the seat ring 20). Moreover, the symbol r2 in the figure indicates the radius of the outermost diameter portion of the valve contact portion 21. The symbol o2 indicates the valve center (center of the shaft portion of the intake valve 6). The symbol t is a thickness in the radial direction of the seat ring 20 that extends from the outer surface 23 of the seat ring 20 to the inner surface of the flow passage in a portion excluding the throat portion 22 and the valve contact portion 21. In this embodiment, the wall thickness t is constant over the entire circumference.

  As described above, in the intake port structure in which the seat ring 20 includes the valve contact portion 21 with which the intake valve 6 contacts and the throat portion 22 on the back side of the valve contact portion 21, Since the center line q2 is eccentrically arranged near the axis x of the cylinder bore with respect to the center line q1 of the flow path of the seat ring 20, the throat portion 22 is located closer to the cylinder bore than the rear end side far from the axis x of the cylinder bore. The front end side closer to the axial center x can be formed deeper toward the back side.

  In FIG. 2, reference sign L <b> 21 a is the depth of the valve contact portion 21 on the front end side (the length in the busbar direction; the same applies hereinafter). Symbol L21b is the depth of the valve contact portion 21 on the rear end side. The depth of the valve abutting portion 21 is preferably in a relationship of L21a = L21b as in this embodiment in order to make the contact pressure with the intake valve 6 uniform over the entire circumference.

  Reference sign L22a is the depth of the throat portion 22 on the front end side (the length in the busbar direction; the same applies hereinafter). Reference sign L22b is the depth of the throat portion 22 on the rear end side. The depth of the throat portion 22 is preferably in a relationship of L22a> L22b.

  By forming the throat portion 22 in such a shape, the intake air is smoothly guided to the axial center x of the cylinder bore, that is, the axial center x side of the combustion chamber 3 on the front end side, and the intake air is input on the rear end side. By suppressing the separation of the intake air from the inner surface of the port 5, the tumble ratio can be improved. For this reason, the tumble flow in the fuel chamber 3 can be strengthened without complicating the structure.

  Further, since the center line q2 of the intake valve 6 is arranged eccentrically toward the axis x of the cylinder bore with respect to the center line q1 of the flow path of the seat ring 20, the throat portion 22 and the valve contact portion 21 are processed. The throat cutter A and the seat cutter B can be constructed in a state of being arranged coaxially with the center line q2 of the intake valve 6, and the work can be performed easily and with high accuracy.

  FIG. 5 shows the effect of improving the tumble ratio of the present invention. In the conventional engine, the flow rate and the tumble ratio are in a trade-off relationship, and there is a problem that the tumble ratio decreases when the flow rate is increased. However, according to the present invention, since the tumble ratio can be increased while increasing the flow rate, the conventional trade-off relationship between the flow rate and the tumble ratio can be improved.

  Another embodiment is shown in FIG.

  In the embodiment shown in FIG. 6, the inner surface of the intake port 5 (hereinafter referred to as the seat ring upstream portion 30) that is continuous with the upstream side of the inner surface of the seat ring 20 is a bottom view from the combustion chamber 3 side, that is, combustion. In plan view along the direction of the center line q1 of the flow path of the seat ring 20 from the chamber 3 side, an inner surface matching portion 32 that is flush with the inner surface of the seat ring 20 is provided on the rear end side far from the axis x of the cylinder bore. In this embodiment, the rear end portion 31 d in the figure corresponds to the inner surface matching portion 32.

  Further, in the other part of the seat ring upstream portion 30, that is, in the plan view, the seat ring is attached to the front end side close to the axis x of the cylinder bore and the side portions on both sides connecting the front end side and the rear end side. An overhanging portion 31 that protrudes inward from the inner surface of 20 is provided. In this embodiment, the front end portion 31 c and the side portions 31 a and 31 b in FIG. And the cross-sectional shape of the seat ring upstream portion 30 is a so-called oval shape in which the maximum diameter in the front-rear direction connecting the front end portion and the rear end portion is set larger than the maximum diameter in the width direction orthogonal to the front end portion. It has become.

  Due to the overhanging portion 31, the cross-sectional area of the flow path of the seat ring upstream portion 30 becomes smaller than the cross-sectional area of the flow path of the seat ring 20. Thereby, the flow velocity of the intake air into the combustion chamber 3 can be further increased.

  Here, in the upstream portion 30 of the seat ring, the protruding portion 31 is not provided at the rear end portion 31d far from the axis x of the cylinder bore. The overhanging portion 31 is provided at a place excluding the rear end portion 31d. Thereby, while ensuring the flow rate of the intake air on the side close to the inner peripheral surface of the cylinder 1, the flow rate of the intake air can be increased by narrowing the flow path at the other portion, that is, the side where the overhanging portion 31 is provided. . In this experiment, it is possible to further improve the tumble ratio in addition to the above-described effect due to the eccentricity of the seat ring 20 and the intake valve 6 by securing the flow rate at the rear end portion 31d and improving the flow velocity on the other side. It was confirmed by.

Here, the seat ring upstream portion 30, that is, the inner surface of the intake port 5 continuous to the upstream side of the inner surface of the seat ring 20 is the inner surface of the intake port 5 made of a metal such as a casting. It means the part located directly above. The overhanging portion 31 is provided to reduce the cross-sectional area of the flow path in the intake port 5.
For this reason, even if the shaft insertion portion 5 b that supports the shaft portion of the intake valve 6 has a portion protruding from the inner surface of the intake port 5, it does not correspond to the overhang portion 31. Further, even though the inner surface of the bent portion 5c can be seen from the inner surface of the seat ring 20 in the plan view, the inner surface of the bent portion 5c is not intended to reduce the cross-sectional area of the flow path. It does not fall under part 31. The seat ring upstream portion 30 is also a portion where the cross-sectional area of the flow path of the intake port 5 gradually expands toward the combustion chamber 3.

  In addition, as a modified example in which the position and shape of the projecting portion 31 are different, for example, in the plan view, the inner end matching portion 32 is provided on the rear end portion 31d and the front end portion 31c side, and the projecting portions 31a and 31b on both sides are projected. A configuration including the portion 31 can also be adopted. Further, the protruding portion 31 may be provided only in one of the side portions 31 a and 31 b, and the other side portion may be the inner surface matching portion 32.

  In any case, when the overhang portion 31 is provided in the seat ring upstream portion 30, the cross-sectional shape of the seat ring upstream portion 30 is such that the center line q2 of the intake valve 6 and the center line q1 of the flow path of the seat ring 20 are eccentric. It is desirable that the inner diameter of the inner surface, that is, the maximum diameter in the front-rear direction connecting the front end side and the rear end side be set larger than the maximum diameter in the width direction connecting the side portions on both sides.

  The intake port 5 including the seat ring upstream portion 30 is manufactured together with the cylinder head 4 by casting. Since the cross-sectional shape of the seat ring upstream portion 30 is not a perfect circle due to the presence of the overhang portion 31 and the inner surface matching portion 32, the casting mold at the time of casting has such a shape, or after casting The member is cut by a three-dimensional machining center or the like.

  When machining with the throat cutter A, it is desirable to machine the seat ring upstream portion 30 simultaneously with the machining of the seat ring 20 and connect them with a smooth surface. When the seat ring upstream portion 30 and the inner surface of the seat ring 20 are smoothly connected, the processing with the throat cutter A may be performed only on the seat ring 20.

  In these embodiments, the configuration of the present invention has been described by taking a diesel engine for automobiles as an example, but the present invention can be applied to a four-cycle gasoline engine for automobiles, other various uses, and various types of engines.

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston 3 Combustion chamber 4 Cylinder head 5 Intake port 6 Intake valve 7 Exhaust port 8 Exhaust valve 9 Fuel injection apparatus 20 Seat ring 21 Valve contact part 22 Throat part 23 Seat ring outer surface 30 Seat ring upstream part 31 Overhang part 32 Inner surface coincident part o1 seat ring center (center of seat ring flow path)
o2 valve center (center of intake valve)
q1 Seat ring center line (center line of seat ring flow path)
q2 Valve center line (center line of intake valve)

Claims (3)

An intake port connected to the combustion chamber of the engine and opened and closed by an intake valve;
An annular seat ring provided in a region facing the combustion chamber of the intake port;
The seat ring includes a valve abutting portion that extends from the back side toward the combustion chamber side so that the intake valve abuts, and the valve ring that is provided on the far side from the valve abutting portion. It has a throat part that expands toward the contact side,
The center of the inner surface of the flow path of the seat ring in a portion excluding the throat portion and the valve abutting portion, where the thickness in the radial direction from the outer surface of the seat ring is constant over the entire circumference The center line of the intake valve is deviated toward the axis of the cylinder bore with respect to the line ,
The intake port structure for an engine, wherein the throat portion is formed deeper on the front end side closer to the cylinder bore axis than on the rear end side far from the axis of the cylinder bore. The engine intake port structure according to claim 1 , wherein the valve abutting portion is formed so that the depth thereof is equal on the front end side and the rear end side. An intake port connected to the combustion chamber of the engine and opened and closed by an intake valve;
An annular seat ring provided in a region facing the combustion chamber of the intake port;
The seat ring includes a valve abutting portion that extends from the back side toward the combustion chamber side so that the intake valve abuts, and the valve ring that is provided on the far side from the valve abutting portion. In a method for manufacturing an intake port of an engine having a throat portion that expands toward a contact side,
The center of the inner surface of the flow path of the seat ring in a portion excluding the throat portion and the valve abutting portion, where the thickness in the radial direction from the outer surface of the seat ring is constant over the entire circumference The center line of the intake valve is deviated toward the axis of the cylinder bore with respect to the line ,
The throat portion is processed into the inner surface of the seat ring or the inner surface of the intake port by a throat cutter that rotates around the center line of the intake valve,
A method for manufacturing an intake port of an engine, wherein the valve contact portion is processed on an inner surface of the seat ring by a seat cutter that rotates around a center line of the intake valve.

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