JP6156340B2 - Engine intake system - Google Patents

Description

  The present invention relates to an intake device for an engine.

  Conventionally, in a vehicle equipped with an EGR device including an EGR (Exhaust Gas Recirculation) cooler, an EGR valve, and the like, the EGR cooler may be attached to the upper portion of the intake manifold due to space requirements in the engine room. In this case, it is possible to connect an EGR valve to the EGR gas outlet of the EGR cooler, connect a pipe to the EGR gas outlet of the EGR valve, and connect the downstream end of the pipe to the intake inlet pipe of the intake manifold. Has been done. These parts are connected to each other by bolt joining.

  Patent Document 1 discloses an EGR valve in which an EGR valve is connected to an EGR gas introduction portion of the EGR cooler by a bolt, and a surge tank (collector portion) of an intake manifold is connected to the EGR gas lead-out portion of the EGR cooler by a bolt. ing.

Japanese Patent No. 3430815

  The conventional connection structure has the following problems.

  In the case of connecting the piping to the intake manifold, as each part is connected in sequence, manufacturing dimensional errors and connection deviations of the parts are gradually accumulated, and bolts and screws at the last part connection in the plurality of parts connection described above. The positions of the holes may be greatly displaced, making connection work difficult (decreasing connection workability). If the connection is forcibly made in such a case, an excessive stress is generated in each component. When the engine is placed horizontally so that the cylinder row direction faces the vehicle width direction, the piping is positioned on the front side of the intake manifold. The arranged radiator collides with the pipe, and the impact of the collision causes the intake manifold to be displaced rearward together with the pipe, and the intake manifold may interfere with the fuel distribution pipe arranged behind the pipe.

  On the other hand, in the technique described in Patent Document 1, for the same reason, connection workability may be reduced, and excessive stress may be generated in each component.

  The present invention has been made in view of the above circumstances, and prevents deterioration in connection workability when an EGR device is connected to the intake manifold, and makes excessive connections to the intake manifold and the EGR device. An object of the present invention is to provide an intake device for an engine that can prevent the occurrence of various stresses.

In order to solve the above-described problems, the present invention provides an EGR cooler having a heat exchanger for cooling EGR gas, an EGR valve fixed to the EGR cooler, an intake manifold having an inlet for the EGR gas, A pipe for guiding the EGR gas after the flow adjustment by the EGR valve to the introduction port, the EGR valve introducing an EGR gas after the cooling by the EGR cooler, and the EGR gas after the flow adjustment. The EGR cooler is led out from the lead-out port for leading the EGR gas cooled by the heat exchanger to the lead-in passage of the EGR valve, and the lead-out passage of the EGR valve. A relay that accepts the EGR gas and derives the EGR gas from the EGR cooler at a position different from the outlet without passing through the heat exchanger. And a road, said pipe, said has an EGR gas derived from relay passage is configured to direct the inlet, the intake manifold, the intake pipe connected to an intake port of an engine cylinder head And a surge tank connected to the upstream end of the intake pipe, and an intake introduction pipe connected to the upstream end of the surge tank, the introduction port is provided in the surge tank, Inside the intake manifold, there is provided a gas introduction passage for guiding EGR gas introduced from the introduction port to an upstream portion of the intake introduction pipe, and the surge tank and the intake introduction pipe are connected to the cylinder head. A plurality of divided bodies divided in a direction perpendicular to the cylinder row direction, and gas flow path component members are attached to the inner wall surfaces of the surge tank and the intake pipe, Serial gas introduction flow path, said plurality of divided bodies that are farthest from the cylinder head of the divided body and the formed between the gas flow path constituting member, and wherein the intake of the engine Providing the device.

  The “EGR valve fixed to the EGR cooler” in the present invention means that the EGR valve is directly connected to the EGR cooler, and does not mean that the EGR valve is indirectly connected via a pipe or the like.

According to the present invention, since the EGR cooler and the intake manifold are connected via the piping without the EGR valve interposed between the EGR cooler and the intake manifold, the manufacturing dimension error of the EGR valve and the The connection error does not affect the connection between the piping and the intake manifold. Therefore, the operation of connecting the EGR device to the intake manifold can be easily performed without generating excessive stress on the intake manifold and the EGR device.
In addition, according to the present invention, the gas introduction flow path for guiding the EGR gas introduced into the surge tank to the upstream portion of the intake intake pipe is provided inside the intake manifold, so that the EGR gas is guided to the intake intake pipe. EGR gas can be introduced into the intake air introduction pipe without connecting the pipe to the intake air introduction pipe. In addition, intake air (fresh air) and EGR gas supplied to the intake pipe can be mixed in the intake pipe and the surge tank, and the mixture can be distributed to each intake pipe. Therefore, while avoiding the complexity of the structure by providing a pipe for guiding the EGR gas to the intake air introduction pipe, the path length necessary for mixing (mixing) the EGR gas and fresh air is secured, and the EGR gas Can be evenly distributed to each cylinder of the engine.
Further, according to the present invention, after the gas flow path constituting member is attached to the inner wall surface of the divided body that is farthest from the cylinder head, a plurality of divided bodies are joined to each other, thereby providing the gas introduction flow path inside. The manufactured intake manifold can be easily manufactured.

In order to solve the above problems, the present invention provides an EGR cooler having a heat exchanger for cooling EGR gas, an EGR valve fixed to the EGR cooler, an intake manifold having an inlet for the EGR gas, A pipe for guiding the EGR gas after the flow adjustment by the EGR valve to the introduction port, the EGR valve introducing an EGR gas after the cooling by the EGR cooler, and the EGR gas after the flow adjustment. The EGR cooler is led out from the lead-out port for leading the EGR gas cooled by the heat exchanger to the lead-in passage of the EGR valve, and the lead-out passage of the EGR valve. A relay that accepts the EGR gas and derives the EGR gas from the EGR cooler at a position different from the outlet without passing through the heat exchanger. And the pipe is configured to guide the EGR gas led out from the relay passage to the inlet, and the EGR cooler is configured as a separate body from the cylinder head of the engine. The EGR valve is extended in the cylinder row direction of the engine together with the EGR valve at an upper portion of the intake manifold, and an end portion of the EGR cooler on the EGR valve side is a central portion of the intake manifold in the cylinder row direction of the engine An end of the EGR cooler opposite to the EGR valve side is located above an end of one side of the intake manifold in the cylinder row direction of the engine. The inlet of the EGR gas provided is located at a position corresponding to the relay passage of the EGR cooler. Gin is open on the upper side of the central portion in the cylinder row direction, characterized in that to provide an intake system for an engine.
In the present invention, the EGR valve is disposed on the EGR cooler in a state in which a first facing surface facing the EGR valve in the EGR cooler and a second facing surface facing the EGR cooler in the EGR valve are in close contact with each other. Are arranged such that the outlet port that opens at the first opposing surface and the inlet port of the introduction channel that opens at the second opposing surface are opposed to each other and opens at the second opposing surface. It is preferable that the outlet port of the outlet channel and the inlet port of the relay passage that opens at the first opposing surface are opposed to each other.

According to this configuration, the EGR cooler outlet port and the EGR valve introduction channel communicate with each other by bringing the first opposed surface of the EGR cooler into contact with the second opposed surface of the EGR valve, and the EGR valve outlet channel. And the relay passage of the EGR cooler can be communicated with each other. Therefore, the EGR valve can be connected to the EGR cooler without interposing other parts such as piping between the EGR cooler and the EGR valve.

In the present invention, the intake manifold includes an intake pipe connected to an intake port of an engine cylinder head, a surge tank connected to an upstream end of the intake pipe, and an upstream end of the surge tank. An intake inlet pipe connected to the surge tank, and the EGR gas introduced from the inlet inlet is guided to the upstream side of the intake inlet pipe inside the intake manifold. A gas introduction flow path is preferably provided.

According to this configuration, since the gas introduction flow path for guiding the EGR gas introduced into the surge tank to the upstream portion of the intake intake pipe is provided inside the intake manifold, the piping for guiding the EGR gas to the intake introduction pipe is provided. The EGR gas can be introduced into the intake air introduction pipe without being connected to the intake air introduction pipe. In addition, intake air (fresh air) and EGR gas supplied to the intake pipe can be mixed in the intake pipe and the surge tank, and the mixture can be distributed to each intake pipe. Therefore, while avoiding the complexity of the structure by providing a pipe for guiding the EGR gas to the intake air introduction pipe, the path length necessary for mixing (mixing) the EGR gas and fresh air is secured, and the EGR gas Can be evenly distributed to each cylinder of the engine.

In the present invention, it is preferable that the EGR cooler has a housing that houses the heat exchanger, and the pipe is integrally formed with the housing.

According to this configuration, since the pipe is integrally formed with the housing of the EGR cooler, the number of parts to be connected can be reduced. Further, since the number of parts to be connected is small, the number of connection man-hours can be reduced.

In the present invention, the EGR valve is disposed on the EGR cooler in a state in which a first facing surface facing the EGR valve in the EGR cooler and a second facing surface facing the EGR cooler in the EGR valve are in close contact with each other. Are arranged such that the outlet port that opens at the first opposing surface and the inlet port of the introduction channel that opens at the second opposing surface are opposed to each other and opens at the second opposing surface. It is preferable that the outlet port of the outlet channel and the inlet port of the relay passage that opens at the first opposing surface are opposed to each other.

According to this configuration, the EGR cooler outlet port and the EGR valve introduction channel communicate with each other by bringing the first opposed surface of the EGR cooler into contact with the second opposed surface of the EGR valve, and the EGR valve outlet channel. And the relay passage of the EGR cooler can be communicated with each other. Therefore, the EGR valve can be connected to the EGR cooler without interposing other parts such as piping between the EGR cooler and the EGR valve.

  The present invention is particularly useful when the engine is placed horizontally in the engine room at the front of the vehicle so that the cylinder row direction faces the vehicle width direction.

  That is, the EGR gas can be introduced into the intake air introduction pipe without connecting the piping for guiding the EGR gas to the intake air introduction pipe, so that when the vehicle has a frontal collision, the radiator is piped. It is possible to prevent the intake manifold from being displaced rearward together with the pipe due to the impact of the collision, and the intake manifold from interfering with the fuel distribution pipe disposed behind the pipe.

  As described above, according to the present invention, the connection workability when connecting the EGR device to the intake manifold is prevented and excessive stress is generated in the intake manifold and the EGR device by making an unreasonable connection. Can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an engine and an intake device thereof according to an embodiment of the present invention, and shows a state in which an EGR cooler and an EGR valve are omitted. It is a perspective view which shows the intake device in FIG. It is the side view which looked at the air intake apparatus shown in FIG. 2 from the D direction. It is a perspective view showing an intake device in an embodiment of the present invention, and is a figure showing an EGR cooler and an EGR valve in the illustrated state. FIG. 5 is a cross-sectional view showing the intake device shown in FIG. 4 in a state where the intake device is cut at the center in the cylinder row direction. FIG. 6 is a cross-sectional view of the intake device shown in FIG. FIG. 3 is a perspective view of a front divided body of the intake manifold shown in FIG. 2 as viewed from the inside (vehicle rear side). It is a perspective view which shows the gas flow path structural member for forming a gas introduction flow path. FIG. 3 is a perspective view showing a structure in the vicinity of a load receiving member and a load transmission portion in FIG. 2. It is a top view which shows a part of intake device in embodiment of this invention. It is a perspective view which shows the intake device in embodiment of this invention, and is a figure which shows the state which removed the EGR valve | bulb from the EGR cooler. It is a perspective view which shows the intake device in embodiment of this invention, and is a figure which shows the EGR valve side part and EGR gas piping of an EGR cooler with a dashed-two dotted line. FIG. 4 is a side view sequentially illustrating how the intake manifold illustrated in FIG. 3 is broken at the time of a frontal collision of a vehicle, (a) is a diagram illustrating the moment when a radiator collides with a throttle body, and (b) is a result of a collision impact. The figure which shows the state which the throttle body displaced to the vehicle rear side, (c) is a figure which shows the state which the vehicle front side part of the surge tank and the intake air intake pipe was crushed by the impact of the collision.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  The engine 4 (see FIG. 1) in the embodiment of the present invention is a so-called direct injection engine that directly injects fuel into a combustion chamber, and is an in-line four-cylinder engine. The engine 4 is a horizontally mounted engine that is disposed horizontally in the engine room at the front of the vehicle so that the cylinder row direction faces the vehicle width direction.

  The engine 4 includes a cylinder head 40 in which four intake ports and four exhaust ports (both not shown) are formed, and a cylinder block 41 provided on the lower side of the cylinder head 40.

  In the following description, the direction A shown in FIG. 1 is the vehicle front-rear direction, the direction B is the vertical direction, and the direction C is the cylinder row direction (vehicle width direction).

  As shown in FIG. 4, the engine intake device 1 according to the present embodiment includes an intake manifold 2, a fuel distribution pipe 3, an EGR (Exhaust Gas Recirculation) cooler 18, an EGR valve 19, and an EGR gas pipe. 9 and. The EGR device is configured by the EGR cooler 18, the EGR valve 19, the EGR gas pipe 9, and the like.

  The intake manifold 2 is located on the vehicle front side of the engine 4.

  The fuel distribution pipe 3 (so-called fuel rail) is disposed between the engine 4 and the intake manifold 2 so as to extend in the cylinder row direction C, and is fixed to the front surface of the engine 4 (surface on the vehicle front side). The fuel distribution pipe 3 distributes fuel to the injectors of the cylinders of the engine 4. The fuel distribution pipe 3 and the intake manifold 2 are close to each other as shown in FIG.

  Hereinafter, each component will be described in detail.

<Configuration of intake manifold 2>
As shown in FIGS. 1 and 2, the intake manifold 2 includes four intake pipes 5, a surge tank 6, and an intake introduction pipe 7. The intake manifold 2 is made of a synthetic resin material for weight reduction.

  As shown in FIG. 3, the intake pipe 5, the surge tank 6, and the intake introduction pipe 7 are each divided into two in the vehicle longitudinal direction A (direction orthogonal to the cylinder row direction C). Specifically, the intake pipe 5, the surge tank 6, and the intake intake pipe 7 are configured by a rear divided body 20 on the side close to the engine 4 and a front divided body 21 on the side far from the engine 4. The rear part 20 and the front part 21 are integrated by vibration welding.

  That is, the rear divided body 20 is configured by portions of the intake pipe 5, the surge tank 6, and the intake introduction pipe 7 on the side close to the engine 4. On the other hand, the front divided body 21 is constituted by portions of the intake pipe 5, the surge tank 6, and the intake introduction pipe 7 on the side far from the engine 4.

  The wall thickness of the front divided body 21 is smaller than the wall thickness of the rear divided body 20. For example, the wall thickness of the front divided body 21 is 2 mm, and the wall thickness of the rear divided body 20 is 3.5 mm. Thereby, the strength of the front divided body 21 is smaller than the strength of the rear divided body 20.

  As shown in FIG. 3, the boundary line 12 between the front divided body 21 and the rear divided body 20 is located at the center in the vehicle longitudinal direction A in the intake pipe 5 and the surge tank 6. The same applies to the portion extending from the downstream end of the intake pipe 7 to the center in the longitudinal direction.

  On the other hand, the boundary line 12 is inclined so as to gradually approach the front surface of the intake introduction pipe 7 as it approaches the upstream end from the longitudinal center of the intake introduction pipe 7. The boundary line 12 reaches the front surface (the front surface of the vehicle) of the intake air introduction pipe 7 in the vicinity of the upstream end portion of the intake introduction pipe 7 (a portion slightly downstream from the upstream end portion).

  That is, in the portion extending from the vicinity of the upstream end portion of the intake air introduction pipe 7 to the upstream end portion, both the portion close to the engine 4 and the portion far from the engine 4 (the entire circumferential direction of the intake air introduction tube 7) are the rear divided body 20. It is configured as.

  As shown in FIG. 1, the downstream ends of the four intake pipes 5 are respectively connected to four intake ports provided in the cylinder head 40 of the engine 4. The intake pipe 5 supplies a mixture of fresh air, EGR gas, and blow-by gas to the intake port.

  By fixing the intake pipe 5 to the cylinder head 40, the intake manifold 2 is supported by the cylinder head 40 in a cantilever state. That is, the surge tank 6 and the intake pipe 7 are indirectly supported by the engine 4 via the intake pipe 5 and are not directly supported by the engine 4.

  A knock sensor for detecting knocking is attached slightly above an oil separator 16 described later on the front surface (front surface of the vehicle) of the cylinder block 41. In the cantilever support state, the cylinder block 41 of the engine 4 and the intake air introduction pipe 7 are not directly connected, so that the rigidity of the cylinder block 41 in the vicinity of the position where the knock sensor is attached is prevented from changing. Therefore, knocking can be accurately detected by the knock sensor. Further, it is possible to suppress vibration from being input from the cylinder block 41 side to a throttle valve 11a, which will be described later, which requires high opening / closing accuracy to control the output of the engine 4.

  As shown in FIGS. 1 and 2, the surge tank 6 extends in the cylinder row direction C, and is formed such that the width in the vertical direction B gradually decreases from the center in the cylinder row direction C toward both ends. ing. As shown in FIGS. 3 and 5, the front surface (surface on the vehicle front side) of the surge tank 6 has a convex arc shape on the vehicle front side when viewed from the cylinder row direction C.

  Upstream end portions of the four intake pipes 5 are connected to the upper surface of the surge tank 6. Connection portions between the surge tank 6 and the four intake pipes 5 are arranged at regular intervals in the cylinder row direction C on the upper surface of the surge tank 6.

  A downstream end portion of the intake pipe 7 is connected to a lower end portion of the central portion of the surge tank 6 in the cylinder row direction C. The surge tank 6 temporarily stores a mixture of fresh air, EGR gas, and blow-by gas introduced from the intake introduction pipe 7, and further mixes the mixture to supply it to the four intake pipes 5. A gas inlet 6c for introducing EGR gas is formed in the upper portion of the outer wall of the surge tank 6 on the vehicle front side. The gas introduction port 6c is located at an upstream end of a gas introduction flow path 8 to be described later.

  As shown in FIGS. 1 to 6, the front surface of the surge tank 6 (surface on the vehicle front side) is provided with a protrusion 60 that protrudes from the front surface toward the vehicle front side. The protrusion 60 is provided at a position where a radiator (not shown) arranged in front of the intake manifold 2 (front side of the vehicle) can collide with a frontal collision of the vehicle.

  One protrusion 60 is provided on each side of the central portion of the surge tank 6 in the cylinder row direction C. Each protrusion 60 is provided at a position closer to the center (close to the center) than the end of the surge tank 6 in the cylinder row direction C.

  The shape and size of the protrusion 60 allow the radiator disposed in front of the intake manifold 2 to collide with the frontal collision of the vehicle, and does not substantially increase the strength of the surge tank 6 (reinforcement). No) and shape and size.

  In the example shown in FIGS. 1 and 2, the protrusion 60 is formed in a front constricted shape so that the dimensions (height and width) in the vertical direction B and the cylinder row direction C are smaller toward the vehicle front side. More specifically, it is formed in a tapered quadrangular frustum shape on the front side of the vehicle.

  In the example shown in FIGS. 1 and 2, the protrusion length of the protrusion 60 (the length in the vehicle longitudinal direction A) is the vertical direction of the surge tank 6 at the position where the protrusion 60 is provided in the cylinder row direction C. It is set to about 1/4 to 1/3 of the length of B, and is slightly larger than the protruding length (length in the vehicle front-rear direction A) of the portion 61a provided on the front surface of the surge tank 6 in the protruding portion 61 described later. (See FIGS. 3 and 5). The length in the vertical direction B and the cylinder row direction C of the root portion of the projection 60 (the boundary portion with the surge tank 6) is approximately the same as the projection length of the projection 60.

  The interior of the protrusion 60 is hollow, and the end of the protrusion 60 on the vehicle rear side is open to the internal space of the surge tank 6.

  As shown in FIG. 5, a gas introduction flow path 8 that guides EGR gas to an upstream portion of the intake introduction pipe 7 (inside the intake introduction pipe 7) is provided inside the intake manifold 2. The upstream end of the gas introduction channel 8 is connected to the downstream end of the EGR gas pipe 9. The EGR gas pipe 9 is a pipe that leads a part of the exhaust gas discharged from the exhaust port of the engine 4 to the gas introduction flow path 8 via the EGR cooler 18 and the EGR valve 19.

  The gas introduction flow path 8 includes a raised portion 61 formed in a vehicle front side portion (front divided body 21) of the surge tank 6 and the intake introduction pipe 7, and a guide portion 10b of the gas flow path constituting member 10 described later. It is a channel wall. The raised portion 61 is formed on the front surface of the surge tank 6 and the front surface of the intake air intake pipe 7 so as to protrude from the respective front surfaces to the vehicle front side. The raised portion 61 is formed by the inner surface of the outer wall portion of the front divided body 21 bulging outward and the outer surface of the outer wall portion protruding outward.

  That is, as shown in FIGS. 5 and 6, the gas introduction flow path 8 is formed between the raised portion 61 and the gas flow path constituting member 10 provided on the vehicle rear side of the raised portion 61. A space between the raised portion 61 and the gas flow path component 10 is a gas introduction flow path 8. The gas flow path component 10 is integrated with the surge tank 6 and the inner wall surface 7a (see FIG. 7) of the intake pipe 7 by vibration welding.

  As shown in FIGS. 1 and 2, the raised portion 61 is formed at the center portion of the surge tank 6 in the cylinder row direction C and across the front surface of the surge tank 6 and the front surface of the intake air intake pipe 7. The raised portion 61 has an upper raised portion 61 a raised from the front surface of the surge tank 6 and a lower raised portion 61 b raised from the front surface of the intake air introduction pipe 7. The upper raised portion 61a extends in the up-down direction B along the front surface of the surge tank 6, and the lower raised portion 61b extends in the up-down direction B along the front surface of the intake intake pipe 7, and these are continuous with each other. doing.

  As shown in FIGS. 2 to 6, the upper raised portion 61 a has a uniform protruding length (length in the vehicle longitudinal direction A) from the front surface of the surge tank 6 over the entire vertical direction B. On the other hand, the lower raised portion 61b has an inclined portion 610 whose projecting length gradually increases from the upper side to the lower side, and a curved portion 611 that curves from the lower end of the inclined portion 610 to the intake intake pipe 7 side. . The protruding length (the length in the vehicle front-rear direction A) of the portion of the curved portion 611 that protrudes to the front side of the vehicle is longer than the protruding length of the upper raised portion 61a and the protruding length of the protruding portion 60.

  As shown in FIG. 8, the gas flow path component 10 has a fixed portion 10a, a guide portion 10b, a through hole 10c, a gas outlet tube portion 10d, and a collision wall portion 10e. The part is integrally formed of synthetic resin.

  The fixed portion 10 a is formed in a ring shape along the outline of the root portion of the raised portion 61. The fixed portion 10a is fixed to the inner wall surface (surface on the vehicle rear side) 7a (see FIG. 7) of the surge tank 6 and the intake introduction pipe 7.

  The guide portion 10b is a plate-like portion facing the inner wall surface (surface on the vehicle rear side) 7b (see FIG. 7) of the raised portion 61. The outer surface (vehicle front side) of the guide portion 10 b has a shape along the ridge line of the raised portion 61.

  The through hole 10c is a hole penetrating from the lower end portion of the guide portion 10b to the vehicle rear side.

  The gas outlet pipe portion 10d is a cylindrical portion extending from the vehicle rear side end portion of the through hole 10c to the vehicle rear side. That is, the gas outlet pipe portion 10 d extends from the outer wall side of the intake inlet pipe 7 toward the radial center. The distal end portion (the vehicle rear side end portion) of the gas outlet pipe portion 10d is located in the vicinity of the radial center portion of the intake air introduction pipe 7.

  The collision wall portion 10e is a plate-like portion curved in a U shape when viewed from above, and both end portions in the cylinder row direction C are supported by the tip end portion of the gas outlet tube portion 10d. As shown in FIGS. 5 and 6, the collision wall portion 10 e is located near the radial center of the intake air introduction pipe 7.

  The EGR gas that has flowed into the gas introduction channel 8 from the EGR gas pipe 9 flows through the gas introduction channel 8, is led out from the tip of the gas lead-out pipe part 10d, and collides with the collision wall part 10e. Since the EGR gas diffuses by colliding with the collision wall 10e, fresh air that flows into the intake air introduction pipe 7 through the throttle body 11 (see FIGS. 1 to 5) described later, and intake air through the oil separator 16 The blow-by gas flowing into the introduction pipe 7 is sufficiently mixed. As a result, an air-fuel mixture in which fresh air, EGR gas, and blow-by gas are sufficiently mixed is supplied into the cylinder of the engine 4 through the surge tank 6 and the intake pipe 5.

  The upper end of the throttle body 11 is connected to the lower end that is the upstream end of the intake pipe 7. A blow-by gas introduction port 23 (see FIGS. 5 and 6) is formed in an outer wall portion on the vehicle rear side in the longitudinal center portion of the intake air introduction pipe 7. The blow-by gas inlet 23 is connected to the downstream end of the blow-by gas passage 22. The blow-by gas passage 22 is a conduit that guides the blow-by gas from which the lubricating oil has been removed in the oil separator 16 to the intake air introduction pipe 7.

  The intake air introduction pipe 7 introduces fresh air supplied to the intake air introduction pipe 7 via an air cleaner (not shown) and the throttle body 11 with the EGR gas and blow-by gas into the surge tank 6. The intake pipe 7 is inclined forward and downward so that the central axis along the longitudinal direction thereof is lowered on the vehicle front side.

  As shown in FIG. 5, the throttle body 11 includes a throttle valve 11a that adjusts the intake amount of fresh air from which dust and dirt have been removed by an air cleaner, and a cylindrical valve case 11b that accommodates and holds the throttle valve 11a. Have. The valve case 11b is inclined forward and downward so that its central axis is lowered on the front side of the vehicle. The vehicle front side end portion of the throttle body 11 (the front side end portion of the valve case 11 b) protrudes further toward the vehicle front side than the protrusion 60 and the raised portion 61. A flexible pipe 17 (see FIGS. 2 and 3) that guides fresh air to the throttle body 11 is connected to the upstream end of the throttle body 11.

  A fragile portion 13 (see FIGS. 3 and 4) is formed in the vicinity of the upstream side end portion (the rear divided body 20) of the intake pipe 7 along the circumferential direction thereof. The fragile portion 13 is a thin portion formed with a thin wall thickness over the entire circumferential direction of the intake air introduction pipe 7.

  By making the wall thickness of the fragile portion 13 smaller than the wall thickness of other portions of the rear divided body 20 (for example, 2 mm), the strength of the fragile portion 13 is reduced. For example, as shown in FIGS. 5 and 6, the wall thickness can be reduced by forming a groove (notch) having a V-shaped cross section in the intake air introduction pipe 7.

  As shown in FIGS. 3, 5, and 6, a load receiving member 14 that receives the intake air introduction pipe 7 at the time of a frontal collision of the vehicle is provided behind the intake air introduction pipe 7 (vehicle rear side). The load receiving member 14 has a load receiving surface 14a opposite to a vehicle rear side end surface (load transmitting surface 15c) in a load transmitting portion 15 to be described later, and the oil separator 16 is disposed on the front surface of the cylinder block 41 on the vehicle. Is fixed through.

  As shown in FIGS. 3, 5, and 6, a load transmitting portion 15 that protrudes from the surface to the vehicle rear side is provided on the outer wall surface of the intake air introduction pipe 7 on the vehicle rear side. As shown in FIG. 9, the load transmission unit 15 includes a plurality of projecting plates 15 a that project toward the vehicle rear side, and a connecting unit 15 b that couples the projecting plates 15 a to each other. A load transmitting surface 15c is formed at the vehicle rear side end of the plurality of protruding plates 15a.

  As shown in FIGS. 3 and 7, there is a slight gap between the load receiving surface 14 a of the load receiving member 14 and the load transmitting surface 15 c of the load transmitting portion 15. By providing this gap, the vibration of the engine 4 when the engine 4 is operating is not directly transmitted to the throttle body 11 via the load receiving member 14 and the load transmitting portion 15.

<Configuration of EGR cooler 18>
As shown in FIGS. 4 to 6 and 10 to 12, the EGR cooler 18 extends in the cylinder row direction C and is mounted on the intake manifold 2. The EGR cooler 18 is fixed to the upper part of the intake manifold 2 (the upper surface of the intake pipe 5) by bolting. An EGR valve 19 is fixed to one end portion of the EGR cooler 18 in the cylinder row direction C by bolt joining. More specifically, a first facing surface 18e (see FIG. 11) facing the EGR valve 19 in the EGR cooler 18 and a second facing surface 19d (see FIG. 12) facing the EGR cooler 18 in the EGR valve 19 are provided. An EGR valve 19 is fixed to the EGR cooler 18 while being in close contact with each other. The EGR valve 19 is supported by the EGR cooler 18 in a cantilever manner by fixing the first opposed surface 18e and the second opposed surface 19d in close contact with each other.

  The end portion of the EGR cooler 18 on the EGR valve 19 side is located above the center portion of the intake manifold 2 in the cylinder row direction C, and the end portion on the side opposite to the EGR valve 19 is in the cylinder row direction C. Is located on one end of the intake manifold 2.

  The EGR cooler 18 includes a heat exchanger 18g (see FIGS. 5 and 6) and a housing 18a.

  The heat exchanger 18g has a gas passage through which a part of exhaust gas (EGR gas) discharged from the exhaust port of the engine 4 flows and a cooling water passage through which cooling water flows. The EGR gas is cooled by heat exchange between the EGR gas flowing through the gas passage and the cooling water flowing through the cooling water passage.

  The housing 18a accommodates the heat exchanger 18g and extends in the cylinder row direction C. The housing 18a includes an EGR gas inlet (not shown), an EGR gas outlet 18b (see FIG. 11), a relay passage 18c (see FIGS. 5 and 6), a cooling water inlet (not shown), and cooling water. And an outlet (not shown).

  The EGR gas inlet is an opening formed at the end of the housing 18a opposite to the EGR valve 19. The EGR gas introduction port introduces a part of the exhaust gas discharged from the exhaust port of the engine 4 as EGR gas. The EGR gas inlet is in communication with the upstream end of the gas passage in the heat exchanger 18g.

  The EGR gas outlet 18b (see FIG. 11) is an opening formed in an end portion (first opposed surface 18e) on the EGR valve 19 side in the housing 18a. The EGR gas outlet 18 b communicates with an introduction flow path 19 a (see FIG. 10) described later in the EGR valve 19. The EGR gas outlet 18 b leads the EGR gas cooled by the heat exchanger 18 g to the introduction flow path 19 a of the EGR valve 19.

  As shown in FIGS. 5 and 6, the relay passage 18c is separated from the heat exchanger 18g through the passage wall 18h. The upstream end of the relay passage 18c is an EGR gas inlet 18f (see FIG. 11) that opens at the first facing surface 18e. The EGR gas introduction port 18f communicates with a later-described outlet passage 19b (see FIG. 10) in the EGR valve 19. The relay passage 18c receives EGR gas derived from the outlet flow path 19b of the EGR valve 19, and passes the EGR gas from the EGR cooler 18 at a position different from the EGR gas outlet 18b without passing through the heat exchanger 18g. To derive.

  As shown in FIGS. 5 and 6, the EGR gas pipe 9 is integrally formed with the housing 18a. The upstream end of the EGR gas pipe 9 is integrally connected to the downstream end of the relay passage 18c. The downstream end of the EGR gas pipe 9 is connected to a gas inlet 6 c formed in the surge tank 6. More specifically, a flange portion 9a (see FIGS. 4 to 6 and 11) provided at the downstream end of the EGR gas pipe 9 and a flange provided at the peripheral portion of the gas inlet 6c of the intake manifold 2 The part 6d (see FIGS. 5, 6 and 12) is connected by bolt joining.

  A cooling water introduction pipe 24 (see FIGS. 4, 11, and 12) is connected to the cooling water introduction port. Cooling water cooled by a radiator (not shown) is introduced into the cooling water introduction port via a cooling water introduction pipe 24.

  A cooling water outlet pipe 25 (see FIGS. 4, 11, and 12) is connected to the cooling water outlet. The cooling water that has been heat exchanged by the heat exchanger is returned to the radiator via the cooling water outlet and the cooling water outlet pipe 25.

<Configuration of EGR valve 19>
As shown in FIG. 10, the EGR valve 19 includes an introduction flow path 19a, a discharge flow path 19b, and a flow rate adjusting unit 19c.

  The upstream end of the introduction flow path 19a is an EGR gas introduction port 19e that opens at the second opposing surface 19d (see FIG. 12) of the EGR valve 19. The EGR gas inlet 19e is disposed so as to face the EGR gas outlet 18b (see FIG. 11) of the EGR cooler 18.

  The downstream end of the outlet channel 19b is an EGR gas outlet 19f that opens at the second opposing surface 19d (see FIG. 12) of the EGR valve 19. The EGR gas outlet 19f is disposed to face the EGR gas inlet 18f (see FIG. 11) of the relay passage 18c.

  As shown in FIG. 10, the flow rate adjustment unit 19c includes a flow rate adjustment valve 19g, an actuator 19h, and a valve seat 19i.

  The flow rate adjusting valve 19g includes a valve shaft 19j and a conical umbrella portion 19k provided integrally at the tip of the valve shaft 19j.

  The actuator 19h is of a linear solenoid type, for example, and moves the flow rate adjusting valve 19g along the axial direction of the valve shaft 19d based on a control signal from a control unit (not shown).

  The valve seat 19i is provided between the downstream end of the introduction channel 19a and the upstream end of the outlet channel 19b. The valve seat 19i forms an EGR gas passage between the valve seat 19i and the umbrella portion 19k of the flow rate adjusting valve 19g.

  By driving the actuator 19h, the flow rate adjusting valve 19g is moved to adjust the distance between the umbrella portion 19k and the valve seat 19i, thereby adjusting the flow rate of the EGR gas supplied to the intake manifold 2.

  Next, an example of a procedure for connecting the EGR device to the intake manifold 2 will be described.

  First, the EGR cooler 18 is fixed on the intake pipe 5 of the intake manifold 2 by bolting.

  Next, the EGR valve 19 is fixed to the EGR cooler 18 by bolt joining while the second opposing surface 19d of the EGR cooler 18 is brought into close contact with the first opposing surface 18e of the EGR cooler 18. By this fixing, the EGR gas outlet 18b of the EGR cooler 18 and the EGR gas inlet 19e of the EGR valve 19 communicate with each other, and the EGR gas inlet 18f of the EGR cooler 18 and the EGR gas outlet 19f of the EGR valve 19 communicate with each other. .

  Next, the flange portion 9a (see FIGS. 5 and 6) provided at the downstream end of the EGR gas pipe 9 is connected to the flange portion 6d provided in the intake manifold 2 by bolt joining. By this bolt connection, the downstream end of the EGR gas pipe 9 is connected to the gas inlet 6c.

  Through the above steps, the EGR device is connected to the intake manifold 2.

  Next, the flow of EGR gas will be described.

  The EGR gas introduced into the EGR cooler 18 from the exhaust port of the engine 4 is cooled in the EGR cooler 18. The cooled EGR gas is introduced into the introduction passage 19a of the EGR valve 19 from the EGR gas outlet 18b.

  The flow rate of the EGR gas introduced into the introduction channel 19a is adjusted by the flow rate adjustment unit 19c, and is introduced from the outlet channel 19b into the relay passage 18c of the EGR cooler 18. The EGR gas introduced into the relay passage 18c is introduced into the gas introduction passage 8 of the intake manifold 2 via the EGR gas pipe 9.

  The EGR gas introduced into the gas introduction channel 8 flows along the ridge line of the raised portion 61 and is introduced into the gas outlet pipe portion 10d via the curved portion 611. By flowing along the curved portion 611, the EGR gas changes the flow direction without substantially reducing the flow velocity.

  The EGR gas is led out from the tip of the gas outlet pipe part 10d and collides with the collision wall part 10e. The EGR gas quickly diffuses by colliding with the collision wall 10e, and is sufficiently mixed with fresh air and blow-by gas by the diffusion.

  The air-fuel mixture is temporarily stored in the surge tank 6 and further mixed. Thereby, the air-fuel mixture in the surge tank 6 has a uniform EGR gas concentration as a whole. The air-fuel mixture in which the concentration of EGR gas is made uniform is distributed to each intake pipe 5 and supplied to each cylinder of the engine 4.

  Next, how the intake manifold 2 is deformed when the vehicle has a frontal collision will be described.

  When a frontal collision occurs, as shown in FIG. 13A, the radiator R is displaced to the vehicle rear side, and the radiator R collides with the throttle body 11.

  Due to this collision, stress concentrates on the fragile portion 13 and a crack occurs in the fragile portion 13, and the fragile portion 13 is broken as shown in FIG. 13B, and the throttle body 11 is displaced to the vehicle rear side. While dropping off from the intake pipe 7. The impact of the collision is absorbed to some extent by the breakage of the fragile portion 13. Since the fragile portion 13 is quickly broken, the intake manifold 2 is not displaced rearward of the vehicle.

  When the radiator R is further displaced toward the vehicle rear side, the radiator R collides with the lower raised portion 61b. As a result of this collision, stress concentrates on the root portion of the lower raised portion 61b (the boundary portion with the intake air introduction pipe 7), a crack occurs in the root portion, and the root portion is broken. Due to this breakage, the impact of the collision is absorbed to some extent.

  When the radiator R is further displaced toward the rear side of the vehicle, a crack at the base portion of the lower raised portion 61b propagates to the periphery, and the crack spreads to the entire vehicle front side portion of the intake air introduction pipe 7.

  When the radiator R is further displaced toward the vehicle rear side, the radiator R collides with the protrusion 60. As a result of this collision, stress concentrates on the root portion of the protrusion 60 (the boundary portion with the surge tank 6), a crack is generated in the root portion, and the root portion is broken. Due to this breakage, the impact of the collision is absorbed to some extent.

  When the radiator R is further displaced toward the rear side of the vehicle, a crack at the base portion of the projecting portion 60 develops to the surroundings, and the crack spreads over the entire vehicle front side portion of the surge tank 6.

  When the radiator R is further displaced toward the vehicle rear side, as shown in FIG. 13C, the vehicle front side portions of the surge tank 6 and the intake pipe 7 are crushed as a whole. By collapsing the vehicle front side portions of the surge tank 6 and the intake intake pipe 7, the impact of the collision is considerably absorbed.

  Since the impact of the collision is considerably absorbed by the vehicle front side portion of the surge tank 6 and the intake introduction pipe 7, the vehicle rear side portion of the intake manifold 2 is not crushed as shown in FIG. Does not displace to Thereby, it is possible to effectively prevent the intake manifold 2 from interfering with the fuel distribution pipe 3.

  As described above, according to the present embodiment, the EGR cooler 18 and the intake manifold 2 are connected via the EGR gas pipe 9 without the EGR valve 19 interposed between the EGR cooler 18 and the intake manifold 2. Therefore, the manufacturing dimensional error of the EGR valve 19 and the displacement of the connection between the EGR valve 19 and the EGR cooler 18 do not affect the connection between the EGR gas pipe 9 and the intake manifold 2. Therefore, the operation of connecting the EGR device to the intake manifold 2 can be easily performed without generating excessive stress on the intake manifold 2 and the EGR device.

  Further, since the EGR gas pipe 9 is integrally formed with the housing 18a of the EGR cooler 18, the number of parts to be connected can be reduced. Further, since the number of parts to be connected is small, the number of connection man-hours can be reduced.

  Further, by bringing the first opposed surface 18e of the EGR cooler 18 and the second opposed surface 19d of the EGR valve 19 into close contact, the EGR gas outlet 18b of the EGR cooler 18 and the introduction flow path 19a of the EGR valve 19 are communicated with each other. The outlet passage 19b of the EGR valve 19 and the relay passage 18c of the EGR cooler 18 can be communicated with each other. Therefore, the EGR valve 19 can be connected to the EGR cooler 18 without interposing other parts such as piping between the EGR cooler 18 and the EGR valve 19.

  Further, since the gas introduction flow path 8 that guides the EGR gas introduced into the surge tank 6 to the upstream portion of the intake intake pipe 7 is provided inside the intake manifold 2, a pipe for guiding the EGR gas to the intake intake pipe 7. The EGR gas can be introduced into the intake air introduction pipe 7 without being connected to the intake air introduction pipe 7. Further, intake air (fresh air) and EGR gas supplied to the intake pipe 7 can be mixed in the intake pipe 7 and the surge tank 6, and the mixed gas can be distributed to the intake pipes 5. Therefore, while avoiding the complexity of the structure by providing a pipe for guiding the EGR gas to the intake air introduction pipe 7, the path length necessary for mixing (mixing) the EGR gas and fresh air is secured, and the EGR Gas can be evenly distributed to each cylinder of the engine 4.

  Further, after the gas flow path component 10 is attached to the inner wall surface of the front divided body 21, the front divided body 21 and the rear divided body 20 are joined to each other so that the gas intake flow path 8 is provided inside. The manifold 2 can be easily manufactured.

  Further, since the EGR gas can be introduced into the intake air introduction pipe 7 without connecting the pipe for guiding the EGR gas to the intake air introduction pipe 7 to the intake air introduction pipe 7, when the vehicle has a frontal collision, It is possible to prevent the radiator from colliding with the piping, and the intake manifold 2 is displaced rearward together with the piping due to the impact of the collision, and the intake manifold 2 can be prevented from interfering with the fuel distribution pipe 3 arranged behind the piping.

  In addition, in the said embodiment, although the housing 18a of the EGR cooler 18 and the piping 9 for EGR gas are integrally molded, it is not restricted to this. For example, the housing 18a and the EGR gas pipe 9 may be configured separately and connected by bolt joining or the like.

  In the above embodiment, the surge tank 6 and the intake pipe 7 are composed of two divided bodies (a front divided body 21 and a rear divided body 20) divided in the vehicle longitudinal direction A. Not limited to. For example, the surge tank 6 and the intake intake pipe 7 may be composed of three or more divided bodies that are divided in the vehicle longitudinal direction A. When the surge tank 6 and the intake pipe 7 are constituted by three or more divided bodies, the gas introduction flow path 8 includes a divided body on the most vehicle front side of the three or more divided bodies, and the divided body. It is formed between the gas flow path constituting member 10 attached to the inner wall surface.

  Further, in the above embodiment, the engine 4 is a horizontal engine, but instead, a vertical engine, that is, a cylinder row direction in the engine room at the front of the vehicle is directed to the vehicle front-rear direction. An engine arranged vertically may be adopted. When a vertically mounted engine is employed, an intake manifold (not shown) rotates the intake manifold 2 disposed on the vehicle front side of the horizontally mounted engine 4 by 90 degrees clockwise or counterclockwise. Placed in the opposite direction. The intake manifold arranged in this way is composed of two divided bodies divided in the vehicle width direction (direction perpendicular to the cylinder row direction). The gas introduction flow path in the intake manifold is formed between the divided body, which is the farthest from the cylinder head, of the two divided bodies and the gas flow path constituting member.

  When a vertically installed engine is employed, the intake manifold may be composed of three or more divided bodies that are divided in the vehicle width direction. When the intake manifold is composed of three or more divided bodies, the gas introduction flow path is attached to the divided body farthest from the cylinder head among the three or more divided bodies and the inner wall surface of the divided body. Formed between the gas flow path component members.

DESCRIPTION OF SYMBOLS 1 Engine intake device 2 Intake manifold 20 Rear division body 21 Front division body 4 Engine 40 Cylinder head 5 Intake pipe 6 Surge tank 6c Gas introduction port 7 Intake introduction pipe 8 Gas introduction flow path 9 EGR gas pipe 18 EGR cooler 18a Housing 18b EGR gas outlet 18c Relay passage 18e First opposing surface 18f EGR gas inlet 18g of relay passage 18g Heat exchanger 19 EGR valve 19a Introducing channel 19b Outlet channel 19d Second opposing surface 19e EGR gas introduction in introducing channel 19f EGR gas outlet for outlet passage

Claims (7)

An EGR cooler having a heat exchanger for cooling the EGR gas;
An EGR valve fixed to the EGR cooler;
An intake manifold having an inlet for the EGR gas;
A pipe for guiding the EGR gas after the flow adjustment by the EGR valve to the inlet,
The EGR valve has an introduction flow path for introducing EGR gas after cooling by the EGR cooler, and a discharge flow path for deriving EGR gas after the flow rate adjustment,
The EGR cooler receives an EGR gas led out from the outlet passage for leading the EGR gas cooled by the heat exchanger to the inlet passage of the EGR valve and the outlet passage of the EGR valve, and receives the EGR gas. And a relay passage that leads out from the EGR cooler at a position different from the outlet without passing through the heat exchanger,
The pipe is configured to guide the EGR gas led out from the relay passage to the introduction port ,
The intake manifold includes an intake pipe connected to an intake port of a cylinder head of an engine, a surge tank connected to an upstream end of the intake pipe, and an intake introduction connected to an upstream end of the surge tank A tube and
The introduction port is provided in the surge tank,
Inside the intake manifold, there is provided a gas introduction flow path that guides EGR gas introduced from the introduction port to the upstream portion of the intake introduction pipe,
The surge tank and the intake pipe are configured by a plurality of divided bodies that are divided in a direction perpendicular to the cylinder row direction of the cylinder head,
A gas flow path constituting member is attached to the inner wall surface of the surge tank and the intake pipe.
The gas introduction flow path is formed between a divided body that is farthest from the cylinder head among the plurality of divided bodies and the gas flow path constituting member.
An intake device for an engine. An EGR cooler having a heat exchanger for cooling the EGR gas;
An EGR valve fixed to the EGR cooler;
An intake manifold having an inlet for the EGR gas;
A pipe for guiding the EGR gas after the flow adjustment by the EGR valve to the inlet,
The EGR valve has an introduction flow path for introducing EGR gas after cooling by the EGR cooler, and a discharge flow path for deriving EGR gas after the flow rate adjustment,
The EGR cooler receives an EGR gas led out from the outlet passage for leading the EGR gas cooled by the heat exchanger to the inlet passage of the EGR valve and the outlet passage of the EGR valve, and receives the EGR gas. And a relay passage that leads out from the EGR cooler at a position different from the outlet without passing through the heat exchanger,
The pipe is configured to guide the EGR gas led out from the relay passage to the introduction port,
The EGR cooler is configured separately from the cylinder head of the engine, and extends in the cylinder row direction of the engine together with the EGR valve at the top of the intake manifold.
An end portion of the EGR cooler on the EGR valve side is located above a central portion in the cylinder row direction of the engine of the intake manifold,
An end portion of the EGR cooler opposite to the EGR valve side is located above an end portion on one side of the intake manifold in the cylinder row direction of the engine,
The EGR gas inlet provided in the intake manifold opens above the center in the cylinder row direction of the engine at a position corresponding to the relay passage of the EGR cooler.
An intake device for an engine. The intake manifold includes an intake pipe connected to an intake port of a cylinder head of an engine, a surge tank connected to an upstream end of the intake pipe, and an intake introduction connected to an upstream end of the surge tank A tube and
The introduction port is provided in the surge tank,
Inside the intake manifold, there is provided a gas introduction passage for guiding EGR gas introduced from the introduction port to the upstream portion of the intake introduction pipe.
The engine intake device according to claim 2, wherein: The surge tank and the intake pipe are configured by a plurality of divided bodies that are divided in a direction perpendicular to the cylinder row direction of the cylinder head,
A gas flow path constituting member is attached to the inner wall surface of the surge tank and the intake pipe.
The gas introduction flow path is formed between a divided body that is farthest from the cylinder head among the plurality of divided bodies and the gas flow path constituting member.
The engine intake device according to claim 3, wherein: The EGR cooler has a housing that houses the heat exchanger;
The pipe is formed integrally with the housing.
The engine intake device according to any one of claims 1 to 4, wherein The EGR valve is fixed to the EGR cooler in a state where a first facing surface facing the EGR valve in the EGR cooler and a second facing surface facing the EGR cooler in the EGR valve are in close contact with each other. ,
The outlet port that opens at the first opposing surface and the inlet port of the introduction channel that opens at the second opposing surface are arranged to face each other,
The outlet of the outlet channel that opens at the second opposing surface and the inlet of the relay passage that opens at the first opposing surface are arranged to face each other.
The engine intake device according to any one of claims 1 to 5, wherein The engine according to any one of claims 1 to 6, wherein the engine is disposed horizontally in an engine room at a front portion of the vehicle so that a cylinder row direction faces a vehicle width direction. Inhalation device.

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