JP2008057360A - Exhaust gas recirculation device of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the durability of a control valve by improving the cooling performance of an exhaust gas recirculation passage on the upstream side of the control valve in an exhaust gas recirculation device of an engine in which the exhaust recirculation passage on the downstream side of the control valve is formed by the grooves formed in the mating surface of a cylinder head on a cylinder block. <P>SOLUTION: An EGR valve 10 is mounted on the rear end wall of the cylinder head 2 of a straight-type four cycle engine. A groove 11 extending in the direction of the cylinder row on the exhaust port 8 side is formed in the mating surface of the cylinder head 2 on the cylinder block 1, and the end of the groove is made to communicate with the exhaust port 8 of a first cylinder #1 farthest from the EGR valve 10 to form an exhaust gas recirculation passage on the upstream side of the EGR valve 10. A groove 13 extending in the direction of the cylinder row on the intake port 7 side is formed in the mating surface of the cylinder head 2 on the cylinder block 1, and the groove 13 is made to communicate with the intake ports 7 of cylinders #1 to #4 to form an exhaust recirculation passage on the downstream side of the EGR valve 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an exhaust gas recirculation device for an engine that introduces a part of exhaust gas discharged from an engine for automobiles or the like into an intake port of each cylinder via a control valve.

  An exhaust gas recirculation device for an engine that introduces part of exhaust gas discharged from an engine for an automobile into an intake port of each cylinder via a control valve (exhaust gas recirculation control valve), and an exhaust gas recirculation passage downstream of the control valve Is formed by a groove in the cylinder row direction provided on the mating surface of the cylinder head and the cylinder block (for example, see Patent Document 1).

  Thus, by providing a groove in the cylinder row direction on the mating surface of the cylinder head and the cylinder block, an exhaust gas recirculation passage on the downstream side from the control valve to the intake port of each cylinder can be easily formed. The cooling performance of the exhaust gas recirculation passage is improved by flowing near the water jacket of the cylinder head and the cylinder block.

  However, the above conventional technique does not consider the cooling performance of the exhaust gas recirculation passage upstream from the control valve, and prevents deterioration of the durability of the control valve due to the heat of the high-temperature recirculation exhaust gas derived from the exhaust port. I can't.

Japanese Patent Laid-Open No. 10-122036

  Therefore, the cooling performance of the exhaust gas recirculation passage upstream of the control valve of the engine exhaust gas recirculation device in which the exhaust gas recirculation passage downstream of the control valve is formed by the groove on the mating surface of the cylinder head and the cylinder block is improved. It is a problem to improve the durability of.

  The exhaust gas recirculation device for an engine according to the present invention solves the above-described problem, and includes a cylinder block in which a plurality of cylinders are arranged in a row and a cylinder head that covers the top of the cylinder block, and is orthogonal to the cylinder row direction of the cylinder head. An engine body in which an intake port for each cylinder is formed on one side in the width direction, an exhaust port for each cylinder is formed on the other side in the width direction, and a water jacket in which cooling water circulates in the cylinder block and the cylinder head At least one of the mating surfaces of the cylinder head and the cylinder block on the intake port side is provided with a groove in the cylinder row direction that forms an exhaust gas recirculation passage downstream of the exhaust gas recirculation control valve. A communication hole communicating with the intake port is formed in the cylinder head, and a part of the exhaust discharged from the exhaust port is referred to as reflux exhaust. An exhaust gas recirculation device for an engine that is introduced into an intake port of each cylinder through an exhaust gas recirculation passage by opening and closing the exhaust gas recirculation control valve, and the control valve is connected to an outer wall surface on one end side in the cylinder row direction of the engine body, A groove in the cylinder row direction that forms an exhaust gas recirculation passage downstream of the exhaust gas recirculation control valve communicates with the exhaust outlet port of the exhaust gas recirculation control valve, and at least one of the mating surfaces of the cylinder head and the cylinder block of the engine body In addition, a groove that forms an exhaust gas recirculation passage upstream of the exhaust gas recirculation control valve is formed. The groove communicates at one end with the exhaust air inlet of the exhaust gas recirculation control valve, and the exhaust boat side extends in the cylinder row direction. It is characterized in that it communicates with the exhaust port of the cylinder located at the end of the cylinder row or the cylinder farther from the exhaust gas recirculation control valve.

  By configuring the exhaust gas recirculation device of the engine in this manner, the recirculated exhaust gas that has been led out from the exhaust port is a groove provided on at least one of the mating surfaces of the cylinder head and the cylinder block on the upstream side of the exhaust gas recirculation control valve. Is cooled by cooling water flowing through the exhaust gas recirculation passage formed by the engine and circulating through the water jacket of the engine body.

  In particular, a groove forming an exhaust recirculation passage on the upstream side communicates with an exhaust inlet of an exhaust recirculation control valve connected to an outer wall surface at one end in the cylinder row direction of the engine body at one end, and Cooling performance of the exhaust gas recirculation passage on the upstream side is a long groove that extends in the direction of the cylinder row and communicates with the exhaust port of the cylinder located at the other end in the middle of the cylinder row or farther from the exhaust gas recirculation control valve. As a result, the temperature of the recirculated exhaust gas is effectively lowered, and the durability of the exhaust recirculation control valve is improved.

  In addition, in this way, in addition to the exhaust gas recirculation passage downstream from the exhaust gas recirculation control valve, the upstream exhaust gas recirculation passage is formed by a groove formed on one of the mating surfaces of the cylinder head and the cylinder block. Not only the exhaust gas recirculation passage on the downstream side, but also the exhaust gas recirculation passage on the upstream side can be easily and efficiently formed at a time when casting the engine body.

  In the engine exhaust gas recirculation device, the exhaust port in which the groove forming the upstream exhaust gas recirculation passage communicates with the other end is preferably the exhaust port of the cylinder farthest from the exhaust gas recirculation control valve. By doing so, the upstream exhaust gas recirculation passage can be lengthened to further enhance the cooling effect by the water jacket of the engine body, and the temperature of the recirculated exhaust gas can be lowered more effectively. Durability is further improved.

  Further, the groove forming the upstream exhaust gas recirculation passage and the groove forming the downstream exhaust gas recirculation passage are closer to the head bolt hole outside the head bolt hole for inserting the head bolt for fastening the cylinder head to the cylinder block. It is good to form. By doing so, the groove is formed along the head bolt fastening position, and the sealing performance is stabilized.

  In addition, the exhaust gas recirculation device of the engine is provided with an exhaust gas recirculation control valve attached to an end wall on the opposite side (rear end side) to the timing drive mechanism on one end side in the cylinder row direction of the engine body. An upstream communication hole that communicates the end of the groove that forms the upstream exhaust gas recirculation passage with the exhaust inlet of the exhaust gas recirculation control valve, and a groove that forms the downstream exhaust gas passage on the end wall of the attached engine body It is preferable to form a downstream communication hole that communicates the end with the exhaust outlet of the exhaust gas recirculation control valve. By doing so, the exhaust gas recirculation control valve can be stably disposed without hindering the layout of the intake system and the exhaust system, and the remaining portion of the exhaust gas recirculation passage can be easily formed by small processing after casting.

  Thus, according to the present invention, it is possible to improve the durability of the exhaust gas recirculation control valve by improving the cooling performance of the exhaust gas recirculation passage upstream of the exhaust gas recirculation control valve and effectively reducing the temperature of the recirculated exhaust gas. In addition, most of the exhaust gas recirculation passage can be easily and efficiently formed at the time of casting the engine body without using pipes or the like.

  In particular, the groove forming the upstream exhaust gas recirculation passage is configured to introduce the recirculated exhaust gas from the exhaust port of the cylinder farthest from the exhaust gas recirculation control valve, thereby reducing the temperature of the recirculated exhaust gas more effectively. The durability of the reflux control valve can be further improved.

  In particular, the groove that forms the upstream exhaust gas recirculation passage and the groove that forms the downstream exhaust gas recirculation passage are formed outside the head bolt hole and close to the head bolt hole, thereby stabilizing the groove sealing performance. To increase sex.

  In particular, an exhaust gas recirculation control valve is attached to an end wall on the rear end side of the engine body, and an end portion of a groove forming an upstream exhaust gas recirculation passage is communicated with the exhaust gas inlet of the exhaust gas recirculation control valve. Exhaust gas recirculation control without obstructing the layout of the intake system and exhaust system by forming a communication hole and a communication hole that connects the end of the groove forming the downstream exhaust passage to the exhaust outlet of the exhaust gas recirculation control valve The valve can be stably arranged, and the remaining portion of the exhaust gas recirculation passage can be easily formed by small processing after casting.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 3 show an example of the embodiment. 1 is a bottom view of the cylinder head, FIG. 2 is a rear view of the cylinder head, and FIG. 3 is a cross-sectional view taken along the line AA of FIG.

  The engine of this embodiment is an in-line four-cylinder water-cooled gasoline engine, and a cylinder block 1 in which first to fourth cylinders # 1 to # 4 are formed in a row in a parallel arrangement, and a top portion of the cylinder block 1 The cylinder head 2 covers the engine body, and the cylinder block 1 and the cylinder head 2 are respectively formed with water jackets 3 and 4 through which cooling water circulates.

  The cylinder head 2 has combustion chamber recesses 5 of the cylinders # 1 to # 4 formed on the lower surface, and bores of the cylinders # 1 to # 4 are formed on a mating surface with the cylinder block 1 around the combustion chamber recesses 5. A plurality of openings 6 are provided to communicate the water jackets 3 and 4 on the cylinder block 1 side and the cylinder head 2 side through holes of a metal gasket (not shown) in an arrangement along the outside of the contour.

  Further, the cylinder head 2 is formed with intake ports 7 of the cylinders # 1 to # 4 on one side in the width direction orthogonal to the cylinder row direction, and the cylinders # 1 to # 4 on the other side in the width direction. An exhaust port 8 is formed.

  Further, the cylinder head 2 is provided with head bolt holes 9 for inserting head bolts for fastening the cylinder head 2 to the cylinder block 1 at four positions around the bore contour of each cylinder # 1 to # 4. Yes.

  The cylinder head 2 is connected to the outer wall surface at a position closer to the intake port 7 side of the end wall on the opposite side (rear end side) to the timing drive mechanism on one end side in the cylinder row direction of the engine body. An EGR valve 10 (exhaust gas recirculation control valve) of an exhaust gas recirculation device is installed for introducing a part of the exhaust gas derived from the exhaust port 8 into the intake ports 7 of the cylinders # 1 to # 4 as recirculation exhaust gas.

  A groove 11 is formed on the mating surface of the cylinder head 2 with the cylinder block 1 as an exhaust gas recirculation passage upstream of the EGR valve 10.

  The groove 11 extends to the exhaust port 8 side in the width direction along the head rear end surface with the position near the intake port 7 on the head rear end side to which the EGR valve 10 is attached as one end. Outside the head bolt hole 9 around the bore contour of each cylinder # 1 to # 4, close to the head bolt hole 9, a part extends along the head bolt fastening position and extends in the cylinder row direction, and the other end It reaches directly under the exhaust port 8 of the first cylinder # 1 farthest from the EGR valve 10. A communication hole 12 is formed in the cylinder head 2 so that the tip (the other end) of the groove 11 communicates with the exhaust port 8 of the first cylinder # 1.

  Further, as an exhaust gas recirculation passage downstream of the EGR valve 10, a groove 13 extending in the cylinder row direction is formed on the mating surface of the cylinder head 2 on the intake port 7 side with the cylinder block 1.

  This groove 13 is arranged on the intake port 7 side outside the head bolt hole 9 around the bore contour of each cylinder # 1 to # 4, close to the head bolt hole 9 and partially along the head bolt fastening position. The position near the intake port 7 on the rear end side of the head to which the EGR valve 10 is attached extends in the cylinder row direction as one end, and the other end reaches directly below the intake port 7 of the first cylinder # 1 farthest from the EGR valve 10. ing. A communication hole 14 is formed in the cylinder head 2 so that the groove 13 communicates with each intake port 7 at four locations immediately below the intake ports 7 of the cylinders # 1 to # 4.

  The grooves 11 and 13 and the communication holes 12 and 14 that form the upstream and downstream exhaust gas recirculation passages are simultaneously formed when the engine body is cast.

  The end of the groove 11 forming the upstream exhaust gas recirculation passage is communicated with the exhaust inlet of the EGR valve 10 in the cylinder row direction at the position where the EGR valve 10 is attached to the rear end wall of the cylinder head 2. The introduction side communication hole 15 is connected to the exhaust side outlet hole of the EGR valve 10 in the cylinder row direction, and the introduction side communication hole 15 is on the lower side. The lead-out side communication holes 16 are arranged in parallel so as to be on the upper side. The introduction side communication hole 15 and the discharge side communication hole 16 are relatively short in the cylinder row direction, and the discharge side communication hole 16 is relatively long. The grooves 11 forming the upstream exhaust gas recirculation passage and the grooves 13 forming the downstream exhaust gas recirculation passage are respectively shifted from each other in the cylinder row direction via the communication holes 17 and 18, respectively, and the introduction side communication holes. 15 and the outlet side communication hole 16.

  These introduction side communication holes 15, lead-out side communication holes 16, and communication holes 17 and 18 are all formed by machining after casting.

  By configuring the exhaust gas recirculation device of the engine in this way, the recirculated exhaust gas is led out from the exhaust port 8 of the first cylinder # 1 farthest from the EGR valve 10 and provided on the mating surface of the cylinder head 2 with the cylinder block 1. The temperature is lowered to such an extent that the durability of the EGR valve 10 is not impaired by heat dissipation to the cylinder head 2 that flows through the long exhaust gas recirculation passage formed by the groove 11 and is cooled by the cooling water circulating in the water jacket 4. And introduced into the EGR valve 10. The recirculated exhaust flows into the exhaust recirculation passage formed by the groove 13 provided on the mating surface of the cylinder head 2 with the cylinder block 1 even on the downstream side by opening and closing the EGR valve 10, and the cylinder head 2 on the intake port 7 side. The temperature further decreases due to heat dissipation, and is introduced into the intake ports 7 of the cylinders # 1 to # 4 through the communication holes 14.

  In this embodiment, the tip communicates with the exhaust port 8 of the first cylinder # 1 so that the recirculated exhaust is led out from the exhaust port 8 of the first cylinder # 1 farthest from the EGR valve 10 to the exhaust recirculation passage on the upstream side. This is the best example for cooling the recirculated exhaust gas, and this groove 11 is an exhaust gas of a cylinder whose tip is located at least in the middle of the cylinder row or a cylinder farther from the control valve. Any device can be used as long as it communicates with the port, and the design can be changed as appropriate.

FIG. 4 is a cross-sectional view of a cylinder head showing a modification of the above embodiment.
In this example, the upstream exhaust gas recirculation passage is constituted by a groove 11A provided on the mating surface on the cylinder head 2 side and a groove 11B provided on the mating surface on the cylinder block 1 side, and the exhaust gas recirculation passage on the downstream side is also The groove 13A is provided on the mating surface on the cylinder head 2 side and the groove 13B is provided on the mating surface on the cylinder block 1 side. Other configurations are the same as those of the embodiment shown in FIGS. In this case, the temperature of the recirculated exhaust gas is more efficiently lowered by heat dissipation to both the cylinder head 2 side and the cylinder block 1 side.

  In addition, the grooves constituting the upstream and downstream exhaust passages can both be provided on the cylinder block side. Also, one of the grooves constituting the upstream and downstream exhaust passages can be provided on the cylinder head side, and the other can be provided on the cylinder block side. The present invention can be implemented in various other modes.

It is a bottom view of the cylinder head in an embodiment. It is a rear view of the cylinder head in an embodiment. It is AA sectional drawing of FIG. It is sectional drawing of the cylinder head which shows the modification of embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder head 3, 4 Water jacket 7 Intake port 8 Exhaust port 9 Head bolt hole 10 EGR valve (exhaust recirculation control valve)
11, 11A, 11B Groove (upstream exhaust recirculation passage)
12 Communication hole 13, 13A, 13B Groove (downstream exhaust gas recirculation passage)
14 communication hole 15 introduction side communication hole 16 lead-out side communication hole 17, 18 communication hole # 1 to # 4 cylinder (first cylinder to fourth cylinder)

Claims (4)

A cylinder block having a plurality of cylinders arranged in a row and a cylinder head covering the top of the cylinder block, and an intake port for each cylinder is formed on one side in the width direction perpendicular to the cylinder row direction of the cylinder head The cylinder head and the cylinder block on the intake port side of the engine body in which an exhaust port of each cylinder is formed on the other side in the width direction and a water jacket in which cooling water circulates is formed in the cylinder block and the cylinder head. A cylinder row direction groove that forms an exhaust gas recirculation passage on the downstream side of the exhaust gas recirculation control valve is provided on at least one of the mating surfaces, and a communication hole that communicates the groove with an intake port of each cylinder is provided in the cylinder head A part of the exhaust discharged from the exhaust port is used as a recirculation exhaust to open and close the exhaust recirculation control valve Ri A exhaust gas recirculation system for an engine to be introduced into the intake port of each cylinder through the exhaust gas recirculation passage,
The exhaust gas recirculation control valve is connected to an outer wall surface on one end side in the cylinder row direction of the engine body, and the groove communicates with an exhaust outlet of the exhaust gas recirculation control valve;
A groove that forms an exhaust gas recirculation passage upstream of the exhaust gas recirculation control valve is formed in at least one of the mating surfaces of the cylinder head and the cylinder block of the engine body, and the groove is at one end of the exhaust gas recirculation control. Communicating with the exhaust introduction port of the valve, extending the exhaust boat side in the cylinder row direction, and communicating with the exhaust port of the cylinder located at the other end in the middle of the cylinder row or a cylinder farther from the exhaust gas recirculation control valve An exhaust gas recirculation device for an engine. 2. The exhaust gas recirculation device for an engine according to claim 1, wherein the exhaust port in which a groove forming the upstream exhaust gas recirculation passage communicates with the other end is an exhaust port of a cylinder farthest from the exhaust gas recirculation control valve. The groove that forms the exhaust gas recirculation passage on the upstream side and the groove that forms the exhaust gas recirculation passage on the downstream side are arranged outside the head bolt hole for inserting the head bolt to fasten the cylinder head to the cylinder block. The exhaust gas recirculation device for an engine according to claim 1 or 2, wherein the exhaust gas recirculation device is formed close to the hole. The exhaust gas recirculation control valve is attached to an end wall opposite to the timing drive mechanism that is one end side in the cylinder row direction of the engine body, and an end portion of a groove that forms the upstream exhaust gas recirculation passage in the end wall An upstream communication hole that communicates with the exhaust inlet of the exhaust recirculation control valve, and a downstream communication hole that communicates the end of the groove forming the downstream exhaust passage with the exhaust outlet of the exhaust recirculation control valve. 4. The exhaust gas recirculation device for an engine according to claim 1, wherein the exhaust gas recirculation device is formed.

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