JP6524728B2 - Engine intake port structure - Google Patents

Description

  The present invention relates to an intake port structure of an engine that enhances swirl flow in a combustion chamber.

  In engines mounted on vehicles etc., an exhaust gas recirculation system is widely adopted which reduces the combustion temperature by recirculating a part of the exhaust gas to the intake passage to suppress the emission of nitrogen oxides from the engine. . In addition, various techniques have been proposed for reducing engine knocking by using the exhaust gas recirculated to the intake passage by the exhaust gas recirculation device (hereinafter, referred to as reflux gas).

  For example, in Patent Document 1, the outlet for the return gas into the intake passage is disposed in the vicinity of the combustion chamber, and the direction of the outlet is set so that the return gas is along the inner circumferential wall of the combustion chamber. As a result, the reflux gas swirls on the swirl flow along the inner circumferential wall of the combustion chamber, and an annular reflux gas layer of active gas is formed in the combustion chamber along the inner circumferential wall. Since the igniter is at the center of the cylinder head, self-ignition of the end gas near the inner circumferential wall is suppressed to reduce knocking while securing good ignition performance at the center of the combustion chamber.

  Further, in Patent Document 2, the valve operation is performed in a normal open / close mode in which all of a plurality of intake valves and exhaust valves are opened and closed, and a part of a plurality of intake valves and exhaust valves is opened and closed. It is possible to switch to a partial open / close mode that generates a swirl flow. In the exhaust gas recirculation apparatus, the direction of the discharge port to the intake passage is set along the swirling direction of the swirl flow along the inner circumferential wall of the combustion chamber, and when the partial opening / closing mode of the valve is selected An annular swirling gas layer is formed in a portion along the inner circumferential wall in the combustion chamber by generating a swirl flow of intake air containing a large amount of gas.

Japanese Patent Application Laid-Open No. 62-131961 JP, 2013-87628, A

  As described above, it is effective to reduce knocking by forming an annular reflux gas layer in a portion along the inner circumferential wall in the combustion chamber by the swirl flow. In addition, the enhancement of the swirl flow is also effective in improving the combustion speed in the combustion chamber.

  However, the inflow direction of intake air from the intake port to the combustion chamber is based on a direction parallel to the direction connecting the intake side and the exhaust side across the cylinder axis of the combustion chamber. The inflow direction is usually also perpendicular to the axial direction of the crankshaft in a plan view of the cylinder of the engine. Therefore, the direction of the swirl flow to be generated in the combustion chamber, that is, the circular arc direction along the inner peripheral wall of the combustion chamber, and the inflow direction of the intake air to the combustion chamber are different from each other. In order to strengthen the swirl flow, it is desirable that the arc direction of the swirl flow and the inflow direction of the intake be close to each other.

  Here, in order to strengthen the swirl flow, it is also possible to adopt a method of adding various valve devices and nozzles in the intake passage. However, the addition of such a device has limitations because it leads to complication of the structure of the engine and an increase in cost.

  Therefore, an object of the present invention is to enhance the swirl flow in the combustion chamber without complicating the structure of the engine.

  In order to solve the above problems, the present invention relates to a plurality of intake ports connected to the intake side of a combustion chamber of an engine for introducing intake air into the combustion chamber, and an exhaust port connected to the exhaust side of the combustion chamber of the engine An annular seat ring provided in a region facing the combustion chamber of the intake port and the exhaust port, an intake valve and an exhaust valve contacting and separating the seat ring, and a port injection valve for injecting fuel into the intake port And at least one of the intake ports has a cross-sectional area of a flow path formed by the inner surface of the intake port continuing on the upstream side of the inner surface of the seat ring in plan view along the axial direction of the seat ring An upstream reduced intake port set smaller than a cross-sectional area of a flow passage formed by the inner surface of the seat ring, and the upstream reduced intake port An inner wall farther from an intake center line connecting an intake side center and an exhaust side center of an inner peripheral wall of a cylinder bore constituting the combustion chamber is gradually moved away from the intake center line as the combustion chamber is approached. The intake port structure of the inclined engine was adopted.

  In this configuration, a port injection valve for injecting fuel into the intake port may be provided, and fuel injection by the port injection valve may be performed on the intake port other than the upstream reduced intake port. .

  Here, the range of fuel injection by the port injection valve may be limited to a range close to the axial center of the cylinder bore in the flow path of the intake valve hole formed by the inner surface of the seat ring. it can.

  In each of these configurations, a low concentration introducing a low concentration combustion component gas having a lower fuel concentration or a lower oxygen concentration than intake air including fuel flowing in the intake port from the inlet opening to the upstream reduced intake port A combustion component gas introduction device may be provided, and the introduction port may be configured to open at an inner wall far from the intake / exhaust center line of the upstream reduced intake port.

  At this time, the low concentration combustion component gas introduction device exhausts the exhaust gas discharged from the combustion chamber as a low concentration combustion component gas from the introduction port into the intake port, or the exhaust gas recirculation device It is possible to employ an air introducing device for introducing the air immediately downstream of the throttle valve provided in the port into the intake port from the inlet as the low concentration combustion component gas.

  Alternatively, the low concentration combustion component gas introduction device comprises: an exhaust gas recirculation device for recirculating air from the introduction port into the intake port as a partial low concentration combustion component gas of exhaust gas discharged from a combustion chamber; It is possible to employ a configuration in which it is used in combination with an air introduction device which is introduced into the intake port from the introduction port as the component gas.

In each of these configurations, the center of the intake valve in the upstream portion reduced intake port is eccentric to the exhaust port side with respect to the center of the inner surface of the seat ring, and parallel to the intake / exhaust center line. Center of the intake valve along an eccentric direction line connecting the center of the intake valve and the center of the inner surface of the seat ring eccentrically on the opposite side of the axial center of the cylinder bore across the wire It is possible to adopt a configuration in which the eccentric side of is formed relatively deeper than the other.

  In each of these configurations, the inner surface of the intake port continuing on the upstream side of the inner surface of the seat ring in the upstream reduced intake port is the eccentric direction line in a plan view along the axial center direction of the seat ring. An inner surface matching portion flush with the inner surface of the seat ring is provided at the rear end side distant from the axial center of the cylinder bore along the outer surface, and any other portion has an overhang portion projecting inward of the inner surface of the seat ring. It is possible to adopt a configuration in which the cross-sectional area of the flow path at the location where the overhanging portion is present is smaller than the cross-sectional area of the flow path of the seat ring.

  Furthermore, the inner surface of the intake port continuing on the upstream side of the inner surface of the seat ring in the upstream portion reduced intake port extends along the eccentric direction line along the front end side close to the axis of the cylinder bore and the eccentric direction line A configuration can be employed in which the maximum diameter in the front-rear direction connecting the rear end side far from the axial center of the cylinder bore is set larger than the maximum diameter in the width direction orthogonal thereto.

  According to the present invention, the cross-sectional area of the flow passage formed by the inner surface of the intake port continuing on the upstream side of the inner surface of the seat ring in a plan view along at least one intake port along the axial direction of the seat ring The upstream portion reduced intake port is set to be smaller than the cross-sectional area of the flow passage formed by the inner surface of the cylinder, and the upstream reduced inlet port corresponds to the intake side center and the exhaust side center of the inner peripheral wall of the cylinder bore constituting the combustion chamber. The engine has an intake port structure in which the inner wall farther from the intake and exhaust centerline connecting the two is gradually inclined away from the intake and exhaust centerline as it approaches the combustion chamber. With this configuration, it is possible to promote the flow in the swirl direction of the intake air introduced into the combustion chamber in the upstream reduced intake port. Therefore, the swirl flow in the combustion chamber can be enhanced without complicating the structure of the engine.

The embodiment of this invention is shown and it is a principal part enlarged plan view of a combustion chamber and an intake port. (A) and (b) show the modification of the embodiment, and are a principal part top view of a combustion chamber and an intake port. It is a principal part enlarged view of the intake port which shows the embodiment. (A) and (b) are explanatory drawings which show the processing method of an inlet port. It is a principal part enlarged view of the intake port which shows other embodiment. It is a principal part enlarged view of the intake port which shows other embodiment. (A) and (b) are the principal part enlarged views of the intake port which show other embodiment. (A) is a longitudinal cross-sectional view which shows typically the inside of the engine provided with the exhaust gas recirculation apparatus as a low concentration combustion component gas introduction apparatus, (b) is front sectional drawing of an inlet port. It is a top view which shows typically the engine provided with the air introduction device as a low concentration combustion ingredient gas introduction device.

  An embodiment of the present invention will be described based on the drawings. The arrangement of the combustion chamber 3 of the engine and the shape of the intake port 5 are shown in FIG. Moreover, the modification is shown in FIG. 2 (a) and FIG.2 (b). Further, the whole of the cylinder 1 and the details of the intake port 5 are shown in FIG.

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

  The engine of this embodiment is a four-stroke gasoline engine for motor vehicles. A piston 2 is accommodated in a cylinder 1 of the engine. The combustion chamber 3 is formed by the inner peripheral wall 3 a of the cylinder bore, the upper surface of the piston 2 and the like. An intake port 5 for feeding intake air into the combustion chamber 3 of each cylinder, an exhaust port 7 extracted from the combustion chamber 3, and a port injection valve 9 for injecting fuel into the combustion chamber 3 are provided. Further, an ignition device is provided at the top of the combustion chamber 3.

  The engine of this embodiment is a four-valve engine, and includes two intake ports 5 connected to the intake side of the combustion chamber 3 and two exhaust ports 7 connected to the exhaust side of the combustion chamber 3. As shown in FIG. 2, the intake port 5 branches into two passages in front of the combustion chamber 3. Although not shown, the exhaust port 7 also branches into two passages in front of the combustion chamber 3.

  However, in the present invention, the numbers of the intake port 5 and the exhaust port 7 can be freely set according to the specification. The number of intake ports 5 may be more than two as long as at least two are provided. Also, the number of exhaust ports 7 may be one, two, or more, for example.

  An intake valve hole 5 a, which is an opening of each intake port 5 to the combustion chamber 3, is opened and closed by the intake valve 6. Further, exhaust valve holes 7 a, which are openings of the exhaust ports 7 to the combustion chamber 3, are opened and closed by the exhaust valve 8. At this time, the intake valve 6 and the exhaust valve 8 contact with and separate 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 to the camshaft side in the cylinder head 4 from a shaft insertion portion opened to the inner surface of the intake port 5 and the exhaust port 7. The shaft insertion portion 5b of the intake port 5 is, as shown in FIG. 8B, a bent portion 5c located on the upstream side of the intake valve hole 5a in the intake port 5 or an opening immediately upstream of the bent portion 5c. doing.

  Of the two intake ports, one intake port 5 shown on the upper side of FIG. 1 is an intake center line A connecting the intake side center D of the inner peripheral wall 3a of the cylinder bore constituting the combustion chamber 3 and the exhaust side center C. The inner wall 5d on the far side is gradually inclined away from the central axis A of the intake and exhaust as it approaches the combustion chamber 3. The inclination angle is an angle α with respect to the intake and exhaust center line A.

  However, in this embodiment, the other side of the intake port 5 shown on the lower side of FIG. 1 is an intake / exhaust center line connecting the intake side center D of the inner peripheral wall 3a of the cylinder bore constituting the combustion chamber 3 and the exhaust side center C. An inner wall 5e on the side far from A is parallel to the suction center line A.

  In each intake port 5, as shown in FIG. 3, the seat ring 20 has a valve contact portion 21 extending from the back to the combustion chamber side so that the intake valve 6 contacts, and the valve contact portion 21 And a throat portion 22 provided on the back side and expanding toward the valve contact portion 21 from the back side.

  As shown in FIG. 3, the inner surface (hereinafter referred to as a seat ring upstream portion 30) of the intake port 5 continuing on the upstream side of the inner surface of the seat ring 20 is one side of the intake port 5 shown on the upper side of FIG. Along the eccentric direction line F1 in a bottom view from the combustion chamber 3 side, that is, in a plan view along the axial center direction of the seat ring 20 from the combustion chamber 3 side, ie, the center line p2 direction of the inner surface 24 of the flow passage. At the rear end side, an inner surface matching portion 32 flush with the inner surface of the seat ring 20 is provided. In this embodiment, the rear end portion 31 d in the drawing corresponds to the inner surface matching portion 32.

  Further, in the other part of the seat ring upstream portion 30, that is, the seat ring on the front end side along the eccentric direction line F1 and the side parts connecting the front end side and the rear end side along the eccentric direction line F1. A projecting portion 31 is provided which protrudes inward from the inner surface of 20. In this embodiment, the front end portion 31 c and the side portions 31 a and 31 b in FIG. 3 correspond to the projecting portion 31. And as for the cross-sectional shape of the seat ring upstream portion 30, the so-called maximum diameter in the front-rear direction connecting between the front end portion 31c and the rear end portion 31d is set larger than the maximum diameter in the width direction orthogonal thereto. It has an oval shape.

  The cross-sectional area of the flow passage of the seat ring upstream portion 30 is smaller than the cross-sectional area of the flow passage of the seat ring 20 by the projecting portion 31, and constitutes an upstream reduced intake port. As a result, the flow velocity of the intake air into the combustion chamber 3 can be further increased, and the intake air can be rapidly induced in the direction of the combustion chamber 3.

  The intake port 5 on the other side shown on the lower side of FIG. 1 is not the upstream reduced intake port but a normal intake port 5. That is, the cross-sectional area of the flow path of the seat ring upstream portion 30 is the same as the cross-sectional area of the flow path of the seat ring 20, and the cross-sectional shape is also set to be the same.

  Here, in the upstream reduced intake port, the overhanging portion 31 is not provided in the rear end portion 31 d of the seat ring upstream portion 30 which is far from the axial center x of the cylinder bore. The overhanging portion 31 is provided at a location excluding the rear end 31 d. Thereby, while securing the flow rate of the intake near the inner peripheral wall 3a of the combustion chamber 3, the flow path is narrowed at the other part, that is, the side provided with the overhang 31 to increase the flow velocity of the intake. It is possible to secure the flow rate at the rear end 31d and to improve the flow velocity on the other side.

Here, the seat ring upstream portion 30, that is, the inner surface of the intake port 5 continuing on the upstream side of the inner surface of the seat ring 20 is the inner surface of the seat ring 20 among the inner surfaces of the intake port 5 made of metal such as casting. It means the part located immediately above. Further, the projecting portion 31 is provided to reduce the cross-sectional area of the flow passage in the intake port 5.
For this reason, even if the shaft insertion portion 5 b supporting the shaft portion of the intake valve 6 has a portion that protrudes to the inner surface of the intake port 5, it does not correspond to the overhang portion 31. The seat ring upstream portion 30 is closer to the combustion chamber 3 than the shaft insertion portion 5 b and is a portion directly above the seat ring 20. Further, even if the inner surface of the bent portion 5c is seen from the inner surface of the seat ring 20 in the plan view, the inner surface of the bent portion 5c is not for reducing the cross-sectional area of the flow passage, It does not correspond to Part 31. The seat ring upstream portion 30 is also a portion where the cross-sectional area of the flow passage of the intake port 5 gradually spreads toward the combustion chamber 3.

  Note that, as a modified example in which the position and the shape of the projecting portion 31 are different, for example, the inner surface matching portion 32 is provided on the side of the rear end 31d and the front end 31c in the plan view, and the projecting portions are side portions 31a and 31b on both sides. A configuration provided with the unit 31 can also be adopted. Alternatively, the overhanging portion 31 may be provided only on 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 projecting portion 31 is provided on the seat ring upstream portion 30, the sectional shape of the seat ring upstream portion 30 is the eccentric direction between the center line p2 of the intake valve 6 and the center line p1 of the flow passage of the seat ring 20. It is desirable that the inner diameter, i.e., 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.

  Although the other intake port 5 shown on the lower side of FIG. 1 is not the upstream reduced intake port but the normal intake port 5, it may be an upstream reduced intake port. At this time, it is desirable that the front end portion 31c be provided with the inner surface matching portion 32 in the plan view so as not to increase the flow velocity of intake air toward the inner peripheral wall 3a of the cylinder bore as much as possible. For example, the front end portion 31c can be provided with the inner surface matching portion 32, and the rear end portion 31d and the side portions 31a and 31b on both sides can be provided with the projecting portion 31.

  In the intake port 5 on one side which is the upstream reduced intake port, as shown in FIGS. 1 and 3, the center o 2 (center line p 2) of each intake valve 6 in the intake port 5 is the flow path of the seat ring 20 Is eccentric to the exhaust port 7 side with respect to the center o1 (center line p1) of the inner surface 24 of the And the center o2 (center line p2) of each intake valve 6 in the intake port 5 passes through the center o1 (center line p1) of the inner surface of the flow path of the seat ring 20, and the inner peripheral wall 3a of the cylinder bore that constitutes the combustion chamber 3 It is decentered on the opposite side of the axial center x of the cylinder bore across an intake / exhaust parallel line E1 parallel to the intake / exhaust center line A connecting the intake side center D and the exhaust side center C.

  In the intake port 5 on the other side, the center o2 of each intake valve 6 corresponds to the center o1 of the inner surface of the flow path of the seat ring 20, and the center o2 of each intake valve 6 is on the intake parallel line E2. Located in

  Here, the aforementioned intake / exhaust center line A is a line connecting the intake side center D and the exhaust side center C of the inner peripheral wall 3a of the cylinder bore in a plan view of the combustion chamber 3. Here, the intake side center D is the middle point between the centers o1 of the inner surfaces 24 of the flow paths in the two intake valve holes 5a, and the exhaust side center C is the center between the inner sides of the flow paths in the two exhaust valve holes 7a. It is the middle point of That is, the intake / exhaust center line A is a direction connecting the intake side and the exhaust side across the axial center x of the cylinder bore constituting the combustion chamber 3 and is orthogonal to the axial center direction of the crankshaft of the engine in plan view It is also a direction.

  Due to the eccentricity of the distance w (see FIG. 1) between the centers, the throat portion 22 of the seat ring 20 in the intake port 5 on one side is the center o 2 of the intake valve 6 and the inner surface of the flow passage of the seat ring 20 The front end side closer to the axial center x of the cylinder bore, that is, the side where the center o2 of the intake valve 6 is eccentric (eccentric side) is formed relatively deeper than the other along the eccentric direction line F1 connecting the center o1 of Constitute an eccentric intake port.

  The fuel injection by the port injection valve 9 provided in the intake port 5 is performed only for the intake port 5 on the other side, as shown in FIG. The fuel injection is not performed to the intake port 5 on one side which is the upstream reduced intake port.

  Further, if it is further necessary, the range of fuel injection by the port injection valve 9 to the intake port 5 on the other side is set in the flow path of the intake valve hole 5a formed by the inner surface 24 of the seat ring 20, It may be limited to the range near the axial center x of the cylinder bore. At this time, in FIG. 1, the injection center line G2 of the fuel is directed to the center o1 of the inner surface 24 of the seat ring 20, but it is directed to the axial center x side of the cylinder bore than the center o1.

  By adopting such a configuration, the fuel can be concentrated in the vicinity of the axial center x of the cylinder bore, and a portion called a knock starting point along the inner peripheral wall 3a of the combustion chamber 3 (a portion shown by a symbol Z in FIG. 1) You can try to supply as little fuel as possible. This can further enhance the knocking reduction effect.

  The modification of this embodiment is shown in Drawing 2 (a) and Drawing 2 (b). Hereinafter, differences from FIG. 1 will be mainly described.

  In the modification of FIG. 2A, the inlet 43 of the low concentration combustion component gas introducing device 40 is opened at the upstream reduced intake port on one side of the two intake ports 5. The direction of the inlet 43 is to the combustion chamber 3 side so that the low concentration combustion component gas to be introduced is smoothly led to the combustion chamber 3 side along the flow of the intake air including the fuel flowing in the intake port 5. It is arrange | positioned so that it may face and open.

  In this embodiment, the low concentration combustion component gas introduction device 40 introduces the reflux gas which is a part of the exhaust gas discharged from the combustion chamber 3 through the exhaust port 7 into the intake port 5 as the low concentration combustion component gas. An exhaust gas recirculation device 40A for recirculating from the port 43 into the intake port 5 is provided.

  As shown in FIG. 8A, the exhaust gas recirculation system 40A sends reflux gas to the intake port 5 through the exhaust gas recirculation passage 41A connecting the exhaust port 7 or the subsequent exhaust passage and the intake port 5 or the subsequent intake passage. It is refluxing. An introduction passage 42A at the end of the exhaust gas recirculation passage 41A is disposed along the flow direction of the intake port 5, and an introduction port 43A opening to a space in the intake port 5 is provided at the end of the introduction passage 42A. An exhaust gas recirculation valve 44 provided in the middle of the exhaust gas recirculation passage 41A adjusts the introduction amount of the reflux gas.

  Further, as shown in FIG. 9, the low concentration combustion component gas introduction device 40 leads the air (new air) immediately downstream of the throttle valve 45 provided in the intake port to the combustion chamber 3 as the low concentration combustion component gas. The air introducing device 40B may be introduced into the intake port 5 through the inlet 43B opened to the intake port 5. As shown in FIG. 9, the air introduction device 40B introduces air to the intake port 5 leading to the combustion chamber 3 through the air introduction passage 41B which is an intake port leading to the outside air. An introduction passage 42B at the end of the air introduction passage 41B is disposed along the flow direction of the intake port 5, and an introduction port 43B opened to a space in the intake port 5 is provided at the end of the introduction passage 42B. A throttle valve 45 provided at the upstream end of the air introduction passage 41B adjusts the amount of air introduced.

  Either the exhaust gas recirculation device 40A or the air introduction device 40B may be employed as the low concentration combustion component gas introduction device 40, or both may be used in combination.

  In the case of the embodiment of FIG. 1 etc. which is not provided with the low concentration combustion component gas introduction device 40, the low concentration combustion component gas introduction device 40 shown in FIGS. 8 and 9 may be omitted. The same applies to each aspect described later.

  In the example of FIG. 2A, the fuel injection by the port injection valve 9 provided in the intake port 5 is performed by the intake port 5 on one side which is an upstream reduced intake port and the other side which is a normal intake port. For both intake ports 5 of the However, when it is desired to further reduce the fuel contained in the swirl flow along the inner circumferential wall 3a, the fuel injection may be set not to be performed to the intake port 5 on one side.

  Further, if necessary, as in the above-described example, the range of fuel injection by the port injection valve 9 at each intake port 5 is the same as that of the flow path of the intake valve hole 5a formed by the inner surface 24 of the seat ring 20. Among these, it may be limited to the range near the axial center x of the cylinder bore.

  In the modification shown in FIG. 2B, one of the two intake ports 5 shown on the upper side in the figure is the intake side center D of the inner peripheral wall 3a of the cylinder bore constituting the combustion chamber 3 and the exhaust The inner wall 5 d remote from the intake and exhaust center line A connecting to the side center C is gradually inclined away from the intake and exhaust center line A as it approaches the combustion chamber 3. Further, the other side of the intake port 5 shown on the lower side in the drawing is the side far from the intake and exhaust center line A connecting the intake side center D of the inner peripheral wall 3a of the cylinder bore constituting the combustion chamber 3 and the exhaust side center C. The inner wall 5 e is inclined in the same direction as the inner wall 5 d on one side with respect to the intake and exhaust center line A. Here, the inner walls 5d and 5e of both are parallel to each other.

  As a form of the fuel injection in the modification of FIG.2 (b), it can be made to be the same as that of the modification of the above-mentioned FIG. 2 (a).

  In each modification of FIGS. 2 (a) and 2 (b), the position of the introduction port 43 of the low concentration combustion component gas introduction device 40 is a side far from the suction center line A among the inner walls of the intake port 5 on one side. It is an inner wall 5d. In this embodiment, in particular, the position of the introduction port 43 is opened on the opposite side of the side of the axis x of the cylinder bore, with the parallel line of air intake and exhaust E1. Therefore, the low concentration combustion component gas such as the reflux gas and the air is quickly supplied near the knock starting point Z close to the inner peripheral wall 3a of the combustion chamber 3, which is more effective for suppressing the knocking.

  The processing of the throat portion 22 in the seat ring 20 is performed as follows. The seat ring 20 before processing is press-fit into a portion of the intake port 5 facing the combustion chamber 3 in advance, and is fixed to the intake port 5.

  As shown in FIG. 4A, the throat cutter A is advanced into the intake port 5 along the axial center coinciding with the center line p2 of the intake valve 6 by a predetermined amount. By rotating the throat cutter A about the center line p2, the inner surface of the seat ring 20 is cut. 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 depending on the specifications. By processing the throat cutter A, a throat portion 22 formed of a conical surface, a spherical surface or the like is formed on the inner surface of the seat ring 20 or the inner surface of the seat ring 20 and the inner surface of the intake port 5.

  The processing of the valve contact portion 21 is performed as follows. After the throat cutter A is removed, as shown in FIG. 4B, the sheet cutter B is advanced into the seat ring 20 along the axial center coincident with the center line p2 of the intake valve 6. By rotating the sheet cutter B around the center line p2, the inner surface of the seat ring 20 is cut. By processing the sheet cutter B, the valve contact portion 21 formed 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 earlier than the valve contact portion 21, and the valve contact portion 21 may be processed earlier than the throat portion 22.

  Further, 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 existence of the projecting portion 31 and the inner surface matching portion 32, the mold of the casting at the time of casting is made to have such a shape or The member is cut by a three-dimensional machining center or the like.

  At the time of processing with the throat cutter A, it is desirable that the sheet ring upstream portion 30 be cut at the same time as the sheet ring 20 is cut and be connected to each other by a smooth surface. When the seat ring upstream portion 30 and the inner surface of the seat ring 20 are connected smoothly, the processing with the throat cutter A may be performed only on the seat ring 20.

  FIG. 3 shows details of the intake port 5 which is an eccentric intake port and an upstream reduced intake port, and the seat ring 20 disposed in the intake port 5.

  The code | symbol r1 shown in FIG. 3 shows the radius of the flow path of the seat ring 20. As shown in FIG. The symbol o1 indicates the seat ring center (the center of the inner surface 24 of the flow passage of the seat ring 20). Further, a symbol r2 in the drawing indicates the radius of the outermost diameter portion of the valve contact portion 21. The symbol o2 indicates the center of the valve (the center of the shaft of the intake valve 6). The code | symbol t0 is the thickness in the radial direction of the seat ring 20 from the outer surface 23 of the seat ring 20 to the inner surface 24 of the flow path of the part except throat part 22 and the valve contact part 21. FIG. In this embodiment, the thickness t0 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 p1 is arranged on the front end side along the eccentric direction line F1 with respect to the center line p2 of the flow path of the seat ring 20, the throat portion 22 is directed to the exhaust side along the eccentric direction line F1. That is, the front end side closer to the axial center x of the cylinder bore along the eccentric direction line F1 is deeper than the other portion including the rear end side distant from the axial center x of the cylinder bore along the eccentric direction line F1. It can be formed deep to the side.

  In FIG. 3, a symbol L <b> 21 a is the depth (the length in the generatrix direction; the same applies hereinafter) of the valve contact portion 21 on the front end side. A symbol L21 b is the depth of the valve contact portion 21 on the rear end side. The depth of the valve contact portion 21 desirably has 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.

  Further, a symbol L22a is the depth of the throat portion 22 at the front end side (the length in the generatrix direction; hereinafter the same). A symbol L22b is the depth of the throat portion 22 on the rear end side. The depth of the throat portion 22 preferably has a relationship of L22a> L22b.

  By forming the throat portion 22 in such a shape, at the front end side along the eccentric direction line F1, the intake air is smoothly guided in the direction of the swirl flow along the inner peripheral wall 3a of the combustion chamber 3, thereby providing anti-knocking performance. The tumble ratio can be improved by suppressing the separation of the intake air from the inner surface of the intake port 5 on the rear end side along the eccentric direction line F1.

  Further, since the center line p2 of the intake valve 6 is eccentrically disposed on the front end side along the eccentric direction line F1 with respect to the center line p1 of the flow path of the seat ring 20, the throat portion 22 and the valve contact portion 21 The throat cutter A and the sheet cutter B for processing can be constructed in a state of being arranged coaxially with the center line p2 of the intake valve 6, and the work can be made easy and highly accurate.

  Another embodiment is shown in FIG. In this embodiment, as in the previous embodiment, the intake port 5 on one side is an upstream reduced intake port and an eccentric intake port.

  The configuration of the seat ring upstream portion 30 in the intake port 5 on one side is basically the same as that of the above-described embodiment, and in a plan view along the axial center direction of the seat ring 20 from the combustion chamber 3 side At the rear end side along F1, an inner surface matching portion 32 flush with the inner surface of the seat ring 20 is provided. In this embodiment, the rear end portion 31 d of FIG. 5 corresponds to the inner surface matching portion 32.

  Further, in the other part of the seat ring upstream portion 30, that is, on the front end side along the eccentric direction line F1 and the side portions 31a and 31b connecting the front end side and the rear end side along the eccentric direction line F1. And an overhanging portion 31 projecting inward from the inner surface of the seat ring 20. In this embodiment, the front end portion 31 c and the side portions 31 a and 31 b in FIG. 5 correspond to the projecting portion 31. The cross-sectional shape of the entire seat ring upstream portion 30 has a so-called oval shape in which the maximum diameter in the front-rear direction connecting the front end side and the rear end side is set larger than the maximum diameter in the width direction orthogonal thereto. The same is true.

  Although the side portions 31a and 31b are linear inner surfaces connecting the rear end portion 31d and the front end portion 31c, the side portions 31a and 31b may be formed in a gentle arc shape.

  As shown in FIG. 5, the outer surface 23 of the seat ring 20 and the inner surface 24 of the flow passage are circular in plan view. The symbol r1 shown in FIG. 5 indicates the radius of the flow channel. The symbol r2 indicates the radius of the outer surface 23. Here, with respect to the center line p2 of the outer surface 23 of the seat ring 20, the center line p1 of the inner surface 24 of the flow path is disposed eccentrically to the rear end side along the eccentric direction line F1.

  The center line of the intake valve 6 coincides with the center line p2 of the outer surface 23 of the seat ring 20. Therefore, the center line p2 of the intake valve 6 is disposed eccentrically to the front end side, that is, the exhaust side, along the eccentric direction line F1 with respect to the center line p1 of the inner surface 24 of the flow path of the seat ring 20. It will be. Hereinafter, similarly to the center line p2 of the outer surface 23 of the seat ring 20, the center line of the intake valve 6 is represented by the symbol p2.

  Here, the symbol o1 in FIG. 5 indicates the center of the inner surface 24 of the flow passage of the seat ring 20. Further, the symbol o2 in the drawing indicates the center of the outer surface 23 of the seat ring 20 (coincident with the center of the shaft of the intake valve 6). The code t1 is the thickness of the thickest portion in the radial direction of the seat ring 20 from the outer surface 23 of the seat ring 20 to the inner surface 24 of the flow passage of the portion excluding the throat 22 and the valve abutment 21 on the front end side. It is thick. The code t2 is the maximum thickness of the seat ring 20 in the radial direction from the outer surface 23 of the seat ring 20 to the inner surface 24 of the flow passage except for the throat 22 and the valve abutment 21 at the rear end side. It is thick. This thickness has a relationship of t1> t2.

  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, the seat ring 20 The center line p2 of the outer surface 23 circular in plan view, that is, the center line p2 of the intake valve 6 with respect to the center line p1 of the inner surface 24 of the flow channel also circular in plan view As the throat portion 22 is disposed eccentrically, the front end side can be formed deeper toward the back side than the rear end side far along the eccentric direction line F1.

  In FIG. 5, reference symbol L21a denotes the depth of the valve contact portion 21 on the front end side (the length in the generatrix direction; the same applies hereinafter). A symbol L21 b is the depth of the valve contact portion 21 on the rear end side. The depth of the valve contact portion 21 desirably has 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.

  Further, a symbol L22a is the depth of the throat portion 22 at the front end side (the length in the generatrix direction; hereinafter the same). A symbol L22b is the depth of the throat portion 22 on the rear end side. The depth of the throat portion 22 preferably has a relationship of L22a> L22b.

  Yet another embodiment is shown in FIG. Also in this embodiment, as in the previous embodiment, the intake port 5 on one side is an upstream reduced intake port and an eccentric intake port.

  The configuration of the seat ring 20 in the intake port 5 on one side is the same as that of each embodiment described above, and the throat portion 22 is deeper on the front end side than on the rear end side farther along the eccentric direction line F1. It forms deeply to the part side. The center o2 of the intake valve is eccentric to the exhaust port side than the center o1 of the inner surface of the seat ring 20 and passes through the center o1 of the inner surface of the seat ring 20 and the intake side center D and the exhaust side center C of the inner peripheral wall of the cylinder bore This configuration is achieved by eccentrically moving on the axial center x side of the cylinder bore with the parallel intake / exhaust parallel line E1 being connected to the intake / exhaust center line A.

  Further, in the seat ring upstream portion 30, along the eccentric direction line F1, an inner surface matching portion 32 is provided at the rear end portion 31d, and a projecting portion 31 is provided at the front end portion 31c and the side portions 31a and 31b. Is the same as Moreover, the point which equips each of the back end part 31d and the front end part 31c with the circular arc-shaped part of the circumference of the axial center of the seat ring 20 is also the same. The same applies in that the side portions 31a and 31b are linear inner surfaces connecting the rear end 31d and the front end 31c.

  In this example, the radius rd of the circular arc portion of the rear end portion 31 d is set larger than the radius rc of the circular arc portion of the front end portion 31 c. Thus, relatively increasing the radius on the rear end portion 31d side is effective for securing the flow rate on the rear end side, and making the radius on the front end portion 31c side relatively small on the front end side It is effective in securing the flow velocity in

  Thus, in the case where the projecting portion 31 is provided at the front end portion 31c, the maximum projecting lengths a and b of the projecting portions 31 of the side portions 31a and 31b from the inner surface of the seat ring 20 are the same as those of the front end portion 31c. It is desirable to set the projection length 31 to be larger than the maximum inward projection length c from the inner surface of the seat ring 20. The amount of reduction of the flow passage cross-sectional area for improving the flow velocity can be secured larger at the side portions 31a and 31b than at the front end 31c. This effect is the same in each of the above-described embodiments.

  Yet another embodiment is shown in FIG. 7 (a). In FIG. 7A, the seat ring 20 has a configuration in which the front end side of the throat portion 22 is more on the back side than the rear end side, which is further along the eccentric direction line F1, as in the embodiments described above. It has formed deep.

  In this aspect, the inner surface matching portion 32 is provided on the rear end portion 31d side in the plan view. In addition, an overhanging portion 31 is provided on the front end portion 31c and the side portions 31a and 31b on both sides. However, the overhanging portions 31 of the side portions 31a and 31b are not linear, and are continuous to the arc-like overhanging portions 31 of the front end 31c only in the portion closer to the front end than the center o1 of the inner surface 24 of the seat ring 20. Similarly, an arc-shaped overhang 31 is provided. The arc-shaped overhanging portion 31 of the side portions 31a and 31b and the arc-shaped overhanging portion 31 of the front end portion 31c are continuous circles having the same radius rc concentrically, these arcs having different radii. It may be Further, the area rc of the overhanging portion 31 may be increased by making the radius rc of the overhanging portion 31 smaller than the radius rd of the arc-shaped inner surface on the rear end portion 31d side.

  Yet another embodiment is shown in FIG. 7 (b). In this aspect, the inner surface matching portion 32 is provided at the rear end portion 31 d and the front end portion 31 c. The overhanging portions 31 are provided on the side portions 31a and 31b on both sides. Also in this embodiment, the cross-sectional shape of the seat ring upstream portion 30 is a so-called oval in which the maximum diameter in the front-rear direction connecting the front end side and the rear end side is set larger than the maximum diameter in the width direction orthogonal thereto. It is a shape.

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

1 cylinder 2 piston 3 combustion chamber 4 cylinder head 5 intake port 6 intake valve 7 exhaust port 8 exhaust valve 9 port injection valve 20 seat ring 21 valve contact portion 22 throat portion 23 outer surface 24 inner surface 30 seat ring upstream portion 31 overhang portion 32 Internal matching portion 40 Low concentration combustion component gas introduction device 43 Introduction port

Claims (7)

A plurality of intake ports connected to the intake side of the combustion chamber of the engine for introducing intake air into the combustion chamber, exhaust ports connected to the exhaust side of the combustion chamber of the engine, the intake port and the combustion chamber of the exhaust port The seat ring includes an annular seat ring provided in an area facing the seat ring, an intake valve and an exhaust valve in contact with and separated from the seat ring, and a port injection valve for injecting fuel into the intake port.
In a plan view along at least one of the intake ports in the axial direction of the seat ring, a cross-sectional area of a flow passage formed by the inner surface of the intake port continuing on the upstream side of the inner surface of the seat ring is the seat It is an upstream reduced intake port set smaller than the cross-sectional area of the flow path formed by the inner surface of the ring,
The upstream reduced intake port is configured such that an inner wall farther from an intake / exhaust center line connecting an intake side center and an exhaust side center of an inner peripheral wall of a cylinder bore constituting the combustion chamber gradually approaches the combustion chamber. It inclines away from the exhaust center line ,
A port injection valve for injecting fuel into the intake port;
An engine intake port structure in which fuel injection by the port injection valve is performed to the intake port other than the upstream reduced intake port . Range of fuel injection by the port injection valve, the intake of the of the seat ring flow channel of the induction valve bore formed by the inner surface of the engine according to claim 1 which is limited to the range of axial center side of the cylinder bore Port structure. A plurality of intake ports connected to the intake side of the combustion chamber of the engine for introducing intake air into the combustion chamber, exhaust ports connected to the exhaust side of the combustion chamber of the engine, the intake port and the combustion chamber of the exhaust port The seat ring includes an annular seat ring provided in an area facing the seat ring, an intake valve and an exhaust valve in contact with and separated from the seat ring, and a port injection valve for injecting fuel into the intake port.
In a plan view along at least one of the intake ports in the axial direction of the seat ring, a cross-sectional area of a flow passage formed by the inner surface of the intake port continuing on the upstream side of the inner surface of the seat ring is the seat It is an upstream reduced intake port set smaller than the cross-sectional area of the flow path formed by the inner surface of the ring,
The upstream reduced intake port is configured such that an inner wall farther from an intake / exhaust center line connecting an intake side center and an exhaust side center of an inner peripheral wall of a cylinder bore constituting the combustion chamber gradually approaches the combustion chamber. It inclines away from the exhaust center line ,
The inner surface of the intake port continued to the upstream side of the inner surface of the seat ring in the upstream reduced intake port is the center of the intake valve and the inner surface of the seat ring in plan view along the axial direction of the seat ring An inner surface matching portion flush with the inner surface of the seat ring is provided on the rear end side distant from the axial center of the cylinder bore along the eccentric direction line connecting the center, and the inner side of the inner surface of the seat ring in any other part. An intake port structure of an engine , comprising: an overhanging portion projecting to an outer surface of the seat ring, wherein a cross-sectional area of the flow passage at a location where the overhanging portion is present is smaller than a cross-sectional area of the flow passage of the seat ring . The inner surface of the intake port continuing on the upstream side of the inner surface of the seat ring in the upstream reduced intake port has a front end closer to the axis of the cylinder bore along the eccentric direction line and a cylinder bore of the cylinder bore along the eccentric direction line. The engine intake port structure according to claim 3 , wherein the maximum diameter in the front-rear direction connecting the rear end side far from the axial center is set larger than the maximum diameter in the width direction orthogonal thereto. A low concentration combustion component gas introducing device for introducing a low concentration combustion component gas having a lower fuel concentration or a lower oxygen concentration than intake air including fuel flowing in the intake port from an inlet opening to the upstream reduced intake port Equipped
The engine intake port structure according to any one of claims 1 to 4, wherein the inlet port is opened to an inner wall of the upstream reduced inlet port remote from the intake / exhaust center line. The low concentration combustion component gas introduction device is provided in an exhaust gas recirculation device which causes part of the exhaust gas discharged from the combustion chamber to be returned from the introduction port into the intake port as the low concentration combustion component gas, or provided in the intake port The engine according to claim 5 , wherein the air introducing device for introducing the air immediately downstream of the throttle valve into the intake port as the low concentration combustion component gas as the low concentration combustion component gas, or the exhaust gas recirculation device and the air introducing device are used in combination. Intake port structure. The center of the intake valve in the upstream reduced intake port is eccentric to the exhaust port side with respect to the center of the inner surface of the seat ring, and the cylinder bore is parallel to the intake center line and is parallel to the intake center line. The eccentric side of the center of the intake valve is more eccentric than the other along the eccentric direction line connecting the throat portion of the seat ring eccentrically to the opposite side of the axial center connecting the center of the intake valve and the center of the inner surface of the seat ring. The engine intake port structure according to any one of claims 1 to 6, which is formed relatively deep.

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