JP2011074890A - Exhaust gas recirculation device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid an increase in the height of a whole internal combustion engine, including a recirculation control valve 18 arranged in an exhaust gas recirculation route 14 formed in a cylinder head 2, at the recirculation control valve and to improve the durability of the recirculation control valve. <P>SOLUTION: A valve housing 15 is formed on a side face of the cylinder head 2 to be recessed sidewise. In the valve housing, both an upstream side recirculation passage 16 from an exhaust system side and a downstream side recirculation passage 17 to an intake system side of the exhaust gas recirculation passage 14 are communicated and the recirculation control valve is mounted sidewise to the side face of the cylinder head so that its opening and closing valve element 18b is inserted in the valve housing. A communication part 16b of the upstream side recirculation passage into the valve housing and a communication part 17a of the downstream side recirculation passage into the valve housing are positioned at a portion on the upstream side from the opening and closing valve element and at a lower portion on the downstream side from the opening and closing valve element part, respectively. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention, in an internal combustion engine, for the purpose of cleaning, etc. of the exhaust gas, to an apparatus for recirculating to the intake system part of the exhaust gas.

  In recent internal combustion engines, a part of the exhaust gas recirculation path from the exhaust system to the intake system is formed inside the cylinder head so as to extend in a direction crossing the cylinder head from the intake side to the exhaust side. That is running.

  In this case, a recirculation control valve is provided in the exhaust gas recirculation path to control the recirculation of the exhaust gas to the intake system in accordance with the operating range of the internal combustion engine.

  Therefore, in Patent Document 1 as a prior art, the recirculation control valve is inserted into a valve housing in which an upper and lower valve bodies of the recirculation control valve are recessed in the upper surface of the cylinder head. In the valve housing, both the upstream recirculation passage from the exhaust system and the downstream recirculation passage to the intake system side in the exhaust gas recirculation path formed inside the cylinder head are communicated and opened. It is proposed to make the structure.

JP 2002-242767 A

  However, according to this prior art, since the recirculation control valve is mounted on the upper surface of the cylinder head so as to protrude from the upper surface, the total height of the internal combustion engine is increased by the recirculation control valve. There is a problem that becomes high.

  In addition, in the exhaust gas recirculation path formed inside the cylinder head, condensed water with high acidity due to moisture in the exhaust gas is generated when the operation of the internal combustion engine is stopped. A large amount of water is generated mainly in the downstream recirculation passage to the intake system side in the exhaust gas recirculation path.

  According to the prior art, the valve housing for accommodating the on-off valve body portion of the recirculation control valve is configured to have a recess formed in the upper surface of the cylinder head, so that the operation of the internal combustion engine is stopped in the valve housing. When this occurs, condensed water with high acidity due to moisture in the exhaust gas accumulates and adheres to the opening / closing valve body inserted in the valve housing. When the engine is started, there is a problem that not only the opening / closing control and the flow rate control by the reflux control valve are seriously disturbed, but also the opening / closing valve body is corroded to reduce its durability.

  The present invention has a technical problem to solve these problems.

In order to achieve this technical problem, claim 1
“In an internal combustion engine in which a part of the exhaust gas recirculation passage from the exhaust system to the intake system is formed inside the cylinder head, and a recirculation control valve is provided in the middle of the exhaust gas recirculation passage.
A valve housing is formed in the side surface of the cylinder head so as to be laterally recessed. In the valve housing, an exhaust gas recirculation passage formed in the cylinder head, an upstream recirculation passage from the exhaust system side, and an intake air On the other hand, on the side of the cylinder head, the reflux control valve is mounted sideways so that the opening / closing valve body is inserted into the valve housing. Further, the communicating portion of the upstream recirculation passage into the valve housing is located at a position upstream of the on-off valve body, and the communicating portion of the downstream recirculation passage into the valve housing is defined as the on-off valve. It is located on the downstream side and lower part than the body part. "
It is characterized by that.

Claim 2
“In the first aspect of the present invention, the cylinder head is provided with a portion overhanging laterally from the cylinder block to which the cylinder head is fastened, and in this portion, the valve housing, the upstream-side return passage, and The downstream reflux passage is provided. "
It is characterized by that.

  According to the first aspect, the exhaust gas flowing in the exhaust gas recirculation passage formed inside the cylinder head from the exhaust system side to the intake system side is appropriately controlled to open and close and the flow rate is controlled by the recirculation control valve.

  In this case, since the recirculation control valve is attached to the side surface of the cylinder head, the overall height of the internal combustion engine can be reliably avoided from being increased by the recirculation control valve.

  On the other hand, the condensed water generated in the valve housing that houses the on-off valve body in the recirculation control valve is sequentially discharged from the communication portion located at a lower position than the on-off valve body to the downstream recirculation passage. Therefore, it is possible to prevent the condensed water from adhering to the on-off valve body, so that the accuracy of on-off control and flow rate control can be improved, and corrosion of the on-off valve body can be suppressed, and the durability of the reflux control valve can be improved. Can be improved.

  According to claim 2, in addition to the above-described effect, the valve housing, the upstream-side return passage, and the downstream-side return passage are provided in a portion of the cylinder head that overhangs from the cylinder block to the side. Therefore, there is an advantage that the cooling performance for the exhaust gas recirculated from the exhaust system to the intake system can be improved.

It is a partially cutaway top view which shows a part of cylinder head in an internal combustion engine. FIG. 2 is an enlarged side view taken along the line II-II in FIG. 1. FIG. 3 is an enlarged sectional view taken along line III-III in FIG. 1. FIG. 4 is an enlarged sectional view taken along line IV-IV in FIGS. 1 and 2.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  In these figures, reference numeral 1 is a cylinder block of an internal combustion engine, reference numeral 2 denotes each of the cylinder heads constituting an internal combustion engine.

  The cylinder block 1 is provided with a plurality of cylinders 3 along the crank axis 4.

  On the other hand, the cylinder head 2 is configured to be fastened to the upper surface of the cylinder block 1 so as to close the cylinders 3. One end of the cylinder head 2 along the crank axis 4 is connected to the cylinder block 1. The cylinder block 1 is provided with a portion 5 overhanging from the side surface 1a extending at right angles to the crank axis 4 to the side along the crank axis 4 by an appropriate dimension L. A cooling water jacket 6 is provided inside the cylinder head 2.

  An exhaust port 9 provided with exhaust valves (not shown) from the cylinders 3 is provided on one of the left and right longitudinal side surfaces 7 and 8 parallel to the crank axis 4 in the cylinder head 2. The exhaust manifold 10 is detachably attached by fastening with a plurality of bolts 11.

  An intake port 12 having an intake valve (not shown) to each cylinder 3 is opened on the other longitudinal side surface 8 of the left and right longitudinal side surfaces 7 and 8 of the cylinder head 2, and an intake manifold. 13 is attached.

  An exhaust gas recirculation passage 14 is formed inside the cylinder head 2 in the overhang portion 5 so as to extend from the exhaust side long side surface 7 toward the intake side long side surface 8.

  In addition, a cylindrical valve housing 15 having an axis extending laterally opens on a side surface 5a of the overhang portion 5 on a side surface 5a perpendicular to the crank axis 4 in the overhang portion 5 of the cylinder head 2. A recess is formed.

  The exhaust gas recirculation passage 14 formed inside the overhang portion 5 includes an upstream recirculation passage 16 between the valve housing 15 and the long side surface 7 on the exhaust side, and the valve housing 15 and the intake side. It is divided into a downstream-side reflux passage 17 between the longitudinal side surface 8.

  On the other hand, a reflux control valve 18 whose axis is oriented horizontally is attached to the side surface 5a of the overhang portion 5 by bolt fastening.

  The recirculation control valve 18 includes an actuator 18a and a valve body portion 18b that is opened and closed by the actuator 18a. The open / close valve body portion 18b is inserted into the valve housing 15. A flange portion 18c provided integrally with the reflux control valve 18 is in close contact with the side surface 5a of the overhang portion 5 and is detachably attached by fastening with a bolt or the like. Alternatively, a seal member 19 such as a gasket is provided.

  Of the exhaust gas recirculation passage 14, an inlet end 16a at one end of the upstream recirculation passage 16 communicates with the exhaust port 9, or communicates with the exhaust manifold 10, and the valve housing 15 at the other end. An inward communication portion (communication port) 16 b is located in a portion of the valve housing 15 upstream of the on-off valve body portion 18 b in the reflux control valve 18.

  In the illustrated embodiment, the upstream-side reflux passage 16 has a groove-type passage 16c formed in the long side surface 7 so as to be recessed, and the groove-type passage 16c is fastened to the long side surface 7 with bolts 11. The lid plate 16d is configured to be closed by the lid plate 16d, and the lid plate 16d is integrated with the exhaust manifold 10, but may be configured separately from the exhaust manifold 10.

  On the other hand, in the exhaust gas recirculation passage 14, the downstream recirculation passage 17 is configured to extend along the lower surface 5b at a portion adjacent to the lower surface 5b in the overhang portion 5, and the valve housing at one end thereof. The communication portion (communication port) 17a to the inside of the valve housing 15 is located downstream of the on-off valve body portion 18b in the reflux control valve 18 and lower than the on-off valve body portion 18b. positioned.

  Incidentally, the valve housing 15, after which casting of the cylinder head 2, are formed by drilling from the side 5a of the overhang portion 5.

  In addition, a communication portion (communication port) 16 b in the upstream recirculation passage 16 into the valve housing 15 is formed by drilling from the long side surface 7 after casting the cylinder head 2.

  Furthermore, a part of the downstream recirculation passage 17 on the side of the valve housing 15 is formed by drilling from the long side surface 7 after casting the cylinder head 2, and one end thereof is formed with a ball 19 or the like. It is configured to be closed by a plug body.

  In this configuration, a part of the exhaust gas discharged from the cylinder 3 through the exhaust port 9 enters the upstream recirculation passage 16 through the inlet end 16a at one end of the upstream recirculation passage 21, and enters the valve housing 15. Thus, after being appropriately controlled according to the operating range of the internal combustion engine by the on-off valve body 18b of the recirculation control valve 18, it is recirculated to the intake manifold 13 via the downstream recirculation passage 17.

  In this case, since the recirculation control valve 18 is attached to the side surface of the cylinder head 2, it can be avoided that the overall height of the internal combustion engine is increased by the recirculation control valve 18.

  Further, a communicating portion (communication port) 17 a to the valve housing 15 in the downstream recirculation passage 17 is downstream of the on-off valve body portion 18 b in the recirculation control valve 18 in the valve housing 15. Due to the low position, the condensed water generated in the valve housing 15 is sequentially discharged from the opening 17 a to the downstream reflux passage 17 without accumulating in the valve housing 15. Therefore, it is possible to avoid the condensed water from adhering to the on-off valve body 18b.

  Furthermore, the valve housing 15, the upstream recirculation passage 16, and the downstream recirculation passage 17 are provided in the portion 5 of the cylinder head 2 that overhangs from the cylinder block 1 to the side. It is possible to improve the cooling performance with respect to the exhaust gas recirculated to the intake system.

DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder head 3 Cylinder 4 Crank axis 5 Overhang part 7 Long side of one side (exhaust side) 8 Long side of the other side (intake side) 9 Exhaust port 10 Exhaust manifold 12 Intake port 13 Intake manifold 14 Exhaust gas recirculation passage DESCRIPTION OF SYMBOLS 15 Valve housing 16 Upstream reflux path 16b Communication part of upstream reflux path into valve housing 17 Downstream reflux path 17a Communication part of downstream reflux path into valve housing 18 Reflux control valve 18a Reflux control valve actuator 18b Reflux control valve disc

Claims (2)

In the internal combustion engine in which a part of the exhaust gas recirculation passage from the exhaust system to the intake system is formed inside the cylinder head, and a recirculation control valve is provided in the middle of the exhaust gas recirculation passage.
A valve housing is formed in the side surface of the cylinder head so as to be laterally recessed. In the valve housing, an exhaust gas recirculation passage formed in the cylinder head, an upstream recirculation passage from the exhaust system side, and an intake air On the other hand, on the side of the cylinder head, the reflux control valve is mounted sideways so that the opening / closing valve body is inserted into the valve housing. Further, the communicating portion of the upstream recirculation passage into the valve housing is located at a position upstream of the on-off valve body, and the communicating portion of the downstream recirculation passage into the valve housing is defined as the on-off valve. An exhaust gas recirculation device for an internal combustion engine, wherein the exhaust gas recirculation device is located downstream and lower than the body portion.   2. The cylinder head according to claim 1, wherein the cylinder head is provided with a portion overhanging laterally from a cylinder block to which the cylinder head is fastened, and the valve housing, the upstream-side return passage, and the An exhaust gas recirculation device for an internal combustion engine, characterized in that a downstream recirculation passage is provided.

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