JP7057173B2 - Internal combustion engine - Google Patents

Description

The present invention relates to an internal combustion engine equipped with an EGR device.

In recent years, internal combustion engines such as internal combustion engines for automobiles are often equipped with an EGR device that recirculates a part of the exhaust gas to the intake system in order to promote purification of the exhaust gas. Often equipped with a water-cooled EGR cooler to cool the EGR gas. Further, in an internal combustion engine, the side on which the timing chain is arranged is called the front, and the side on which the transmission is arranged is called the rear. Cooling in which a thermo valve or the like is arranged at the rear of the cylinder head. A water distribution unit is often provided.

There are various modes of the EGR passage, the arrangement position of the EGR cooler, the piping mode of the cooling water, etc., but in Patent Document 1 as an example, the EGR cooler is arranged on the exhaust side of the engine body and passed through the cylinder head. It is disclosed that the cooling water is taken into the EGR cooler and the cooling water discharged from the EGR cooler is returned to the radiator outlet pipe.

Japanese Unexamined Patent Publication No. 2016-14345

In order to reduce the weight of the internal combustion engine and reduce the pressure loss of the cooling water, it is preferable that the pipeline connected to the EGR cooler is as short as possible, and from the viewpoint of assembly efficiency, the pipes should be connected as easily as possible. Should be.

However, in Patent Document 1, since the cooling water inflow pipeline to the EGR cooler is branched from the pipe connected to the cooling water distribution portion of the cylinder head, the inflow pipeline tends to be long and the weight tends to increase. At the same time, since the cooling water must change direction rapidly at the branch portion, there is a concern that the efficiency of taking the cooling water into the EGR cooler will deteriorate.

The present invention has been made in the wake of such a situation, and is intended to make the pipeline for sending cooling water to the EGR cooler as compact as possible while facilitating assembly.

The internal combustion engine of the present invention is
"Equipped with a cylinder head and a water-cooled EGR cooler,
Cooling water having a tubular EGR feed port that sends cooling water to the EGR cooler projecting backward in the direction opposite to the timing chain at the rear end of the cylinder head on the side opposite to the timing chain arrangement portion. While a distribution unit is provided,
The EGR cooler has a tubular cooling water inlet port connected to the EGR feed port via a cooling water feed pipe, and a tubular cooling water outlet port to which a cooling water return pipe is connected. The cooling water inlet port and the cooling water outlet port are arranged on the outside of the cooling water distribution unit in a state of protruding backward .
The cooling water inlet port of the EGR cooler is inclined toward the EGR feed port as it goes backward. "
It is configured as.

The cooling water distribution section of the cylinder head is formed with a cooling water feed port and a return port, but in general, these ports should be open backward facing the side opposite to the timing chain arrangement section. many. Therefore, it is rational to open the EGR feed port backward of the cylinder head, and the cooling water inlet port of the EGR cooler is also opened backward .

In the present invention, the EGR cooler is arranged outside the cooling water distribution section of the cylinder head, but the EGR cooler can be as close as possible to the cooling water distribution section. Therefore, the EGR feed pipe can be made as short as possible, which can contribute to the weight reduction of the internal combustion engine.

Since the EGR feed port and the cooling water inlet port are oriented in the same direction, the EGR feed pipe connecting them has a simple shape such as a U shape. Therefore, when the EGR feed pipe is made of metal, it is easy to process, while when a flexible hose is used as the EGR feed pipe, it is easy to handle and the connection work can be easily performed.
Further, when assembling the internal combustion engine, since the rear side of the cooling water distribution unit is an open space, in the present invention, the EGR feed pipe can be connected without any obstacles. Therefore, there is an advantage that the workability can be further improved. Further, since the cooling water outlet port of the EGR cooler is also opened backward, there is an advantage that the EGR return pipe can be easily fitted into the cooling water outlet port.

It is a rough perspective view of the internal combustion engine which concerns on embodiment. It is a perspective view in the state which the cylinder block is dismissed. It is an enlarged view of the main part of FIG. It is a side view of the upper part. It is a partially enlarged view of FIG. It is a plan view. It is a rear view. It is a perspective view seen from the upper front. It is a perspective view seen from the lower back. It is a perspective view of the EGR cooler, the EGR valve, and the second part on the downstream side of the EGR passage. It is a front view of a main part. It is a separation perspective view of an EGR valve, an EGR cooler, and a bracket (note that the scales of the three are not exactly aligned). (A) is a bottom view of the EGR valve, (B) is a view of BB of FIG. 12, and (C) is a view of FIG. 12 CC.

(1). Basic structure Next, an embodiment of the present invention will be described with reference to the drawings. This embodiment is applied to a 3-cylinder internal combustion engine mounted on a vehicle. First, an outline will be described. In each figure, there are places where a group of dots and parallel diagonal lines are displayed, but this is a measure to clearly indicate the outer shape (outline) of the member, not the cross section or the like.

FIG. 1 shows the entire internal combustion engine. In this embodiment, front-back and left-right wording are used to specify the direction, but the front-back direction of the engine is defined as the direction of the crank axis O, and the left-right direction is the direction orthogonal to the crank axis O and the cylinder bore axis. It is defined. As for the front and the rear, the side where the timing chain is arranged is the front and the side where the transmission is arranged is the rear, and the directions are clearly shown in FIG. 1 and the like just in case.

The internal combustion engine is mounted in the engine room of the vehicle, but the internal combustion engine is mounted horizontally so that the crank shaft is in a long position in the left-right direction of the vehicle. Therefore, the front-rear direction of the internal combustion engine and the front-rear direction of the vehicle are different by 90 degrees. The directions used below are the directions of the institution unless otherwise noted.

The cylinder block 1 and the cylinder head 2 have an intake side surface to which the intake manifold 3 is fixed and an exhaust side surface to which the exhaust system is connected. However, in the internal combustion engine of the present embodiment, the exhaust side surface is a vehicle. It is arranged so that it faces the front of the engine (when viewed from the direction of the engine, the exhaust side faces right and the intake side faces left).

FIG. 1 shows the internal combustion engine from the rear, and a ring gear 4 driven by a starter motor is arranged at the rear of the cylinder block 1. Reference numeral 5 indicates an oil pan, and reference numeral 6 indicates an oil filter.

The structure of the cylinder head 2 is shown in FIG. As can be understood from this figure, the cylinder head 2 has basically the same structure as the conventional one, and is provided with an intake side longitudinal wall 7, an exhaust side longitudinal wall 8, a front wall 9, and a rear wall 10 around the cylinder head 2. It is open upwards. A front bearing 11 is formed on the front wall 9, and an intermediate bearing 12 and a rear bearing 13 are formed inside.

For example, as shown in the figure, a cooling water distribution unit 14 is integrally formed at the rear portion of the cylinder head 2 (the cooling water distribution unit 14 can be configured separately from the cylinder head 2). .).

The cooling water distribution unit 14 is open with a radiator bound port 15, a radiator return port (thermo chamber) 16, a heater return port 17, an EGR feed port 18, and the like. Each port 15-18 is open backwards. The thermocap 19 shown in FIG. 1 is fixed to the radiator return port 16 shown in FIG. 2.

(2). Outline of intake / exhaust system Although omitted in the figure, a head cover is fixed to the upper surface of the cylinder head 2, and the intake unit 22 is arranged on the head cover. As shown in FIG. 6, the intake unit 22 includes an air cleaner 23 generally arranged above the cylinder head 2, an intake duct 24 connected to the dust chamber of the air cleaner 23, and a resonator 25 connected to the intake duct 24. It is equipped with.

The starting end of the intake duck 24b is open forward (to the right in the direction of the vehicle), and is connected to the air cleaner 23 after making a U-turn in a plan view. The resonator 25 is arranged on the front side of the air cleaner 23, and the intake air flowing through the intake duct 24 flows into the resonator 25 with straightness. The resonator 25 also communicates with the dust chamber of the air cleaner 23. An expansion chamber 26 is connected to the upstream side of the direction changing portion of the intake duct 24.

As shown in FIG. 1, in the clean chamber of the air cleaner 23, an intake outlet 27 located above the intake manifold 3 is formed so as to open downward. On the other hand, as shown in FIGS. 4 and 7, the intake manifold 3 includes a surge tank 28 and three branch pipes 29, and is provided with a receiving seat 30 which is open upward from the front of the surge tank 28. The throttle valve 31 shown in FIGS. 1 and 7 is interposed between the receiving seat 30 of the surge tank 28 and the intake outlet 27 of the air cleaner 23.

For example, as can be understood from FIGS. 7 and 8, the intake manifold 3 is formed in a hollow shape by laminating and welding a plurality of resin parts vertically, and as shown in FIGS. 2 to 4, the branch pipe 29 is formed. Circulates around the surge tank 28 from the bottom to the top for nearly one round, and the tip of each branch pipe 29 is attached to the intake side surface 32 of the cylinder head 2 as shown in FIGS. 7 and 11. It is fixed.

As shown in FIG. 8, one exhaust outlet 34 is open on the exhaust side surface 33 of the cylinder head 2, and the catalyst case 35 shown in FIGS. 1 and 2 is provided at the exhaust outlet 34 as an exhaust turbocharger. It is connected via (not shown). Then, as shown in FIG. 2, the start end of the EGR passage upstream portion 36 made of a metal pipe is connected to the downstream end portion of the catalyst case 35.

On the other hand, an EGR internal passage 37 penetrating the intake side surface and the exhaust side surface is formed in the rear portion of the cylinder head 2, and the end of the EGR passage upstream portion 36 is connected to the start end of the EGR internal passage 37 by flange joining. Has been done. As shown in FIG. 7, the EGR internal passage 37 is inclined so that about half of the upstream side is in a horizontal posture and about half of the downstream side is gradually increased in the flow direction of the EGR gas. are doing. Further, the inclined portion is surrounded by ribs having an arcuate cross section.

For example, as shown in FIGS. 2 and 3, an EGR cooler 40 is connected to the end of the EGR internal passage 37 via a joint pipe 41 and a lower flange 42, and an EGR valve is further connected to the upper end of the EGR cooler 40. 43 is connected. As clearly shown in FIGS. 4 and 5, the EGR cooler 40 and the EGR valve 43 are arranged behind the intake manifold 3. The EGR valve 43 is located higher than the cylinder head 2, and the EGR cooler 40 is also mostly located above the cylinder head 2.

In the present embodiment, the joint pipe 41, the EGR cooler 40, and the EGR valve 43 form the first portion on the downstream side of the EGR passage, and the outlet port 44 (see FIG. 12) of the EGR valve 43 is connected to the second portion on the downstream side of the EGR passage. A portion 45 is connected, and further, an EGR distribution passage 46 for flowing EGR gas separately to the downstream portion of each branch pipe 29 in the intake manifold 3 is connected to the downstream end of the second portion 45 on the downstream side of the EGR passage. .. The second portion 45 on the downstream side of the EGR passage and the EGR distribution passage 46 are cast products such as aluminum, but both can be manufactured as an integral structure product. Alternatively, it can also be manufactured as a resin molded product (composite product).

(3) .Main part of the EGR device The EGR cooler 40 has a square body and is in a long vertical direction (vertical direction), and the EGR gas flows from the bottom to the top. Therefore, an outlet pipe 47 provided with an upper flange 47a is provided at the upper end. The mounting posture of the EGR valve 43 can be arbitrarily set by adjusting the bending method of the outlet pipe 47 and the posture of the upper flange 47a.

The EGR cooler 40 is in a vertically long posture, but as is clearly shown in FIG. 5, in the side view, the EGR cooler 40 is inclined with respect to the vertical line so as to gradually move backward from the cylinder head 2 as it goes up. Further, as shown in FIG. 7, in the rear view, it is inclined with respect to the vertical line so as to move away from the intake manifold 3 as it goes upward. Further, as shown in FIG. 7, the second portion 45 on the downstream side of the EGR passage is inclined in the rear view so as to be lower in the flow direction of the EGR gas.

For example, as clearly shown in FIGS. 9 and 10, a cooling water inlet port 48a and a cooling water outlet port 48b are provided on the rear surface of the EGR cooler 40. The cooling water inlet port 48a is located at the bottom of the body, the cooling water outlet port 48b is located at the top of the body, and inside the body is a heat exchange element through which the cooling water flows from bottom to top. Has been done.

The cooling water inlet port 48a and the cooling water outlet port 48b are formed in a tubular shape by a joint pipe press-fitted into the body and open ( protruding) backward, and as schematically shown in FIG. 3, the cylinder head 2 The EGR feed port 18 and the cooling water inlet port 48a of the EGR cooler 40 are connected by an EGR feed pipe 49a (see also FIG. 1).

As shown in FIGS. 2 and 3, the EGR feed port 18 of the cooling water distribution unit 14 is provided at the end of the cooling water distribution unit 14 on the intake side (left side) of the cylinder head 2, and the EGR cooler 40 is also provided with the cooling water. It is arranged closer to the left side of the outside of the distribution unit 14. Therefore, the distance between the EGR feed port 18 and the cooling water inlet port 48a is narrowed within an allowable range for handling the EGR feed pipe 49a. As is clearly shown in FIG. 4, the EGR feed port 18 is in a horizontal position, but the cooling water inlet port 48a is inclined diagonally downward.

The EGR feed pipe 49a is composed of a flexible hose, the ends of which are fitted into the EGR feed port 18 and the cooling water inlet port 48a against elasticity, and are held by a band so as not to be pulled out. ing. Therefore, a diameter-expanded portion for preventing the EGR feed pipe 49a from coming off is formed at the tips of the ports 48a and 48b. As can be understood from FIG. 4, the EGR feed port 18 is also formed in a cylindrical shape with a joint pipe and protrudes backward (in FIGS. 2 and 3, the EGR feed port 18 is drawn in a state before the joint pipe is press-fitted). ing.).

An EGR return pipe 49b (see FIG. 1) is connected to the cooling water outlet port 48b. The EGR return pipe 49b is also made of flexible porcelain, but both can use metal pipes. The heater return pipe 17a shown in FIG. 1 is connected to the heater return port 17 shown in FIGS. 2 and 3, and the other ends of the heater return pipe 17a and the EGR return pipe 49b are fixed to one joint member. Has been done. Further, as shown in FIG. 1, the heater return pipe 17a and the EGR return pipe 49b intersect with the EGR feed pipe 49a in the rear view. The EGR return pipe 49b can be connected to a heater core, a CVT warmer, or the like.

A port 50 for the EGR valve is provided at the upper end of the EGR cooler 40. Further, auxiliary brackets 51 and 52 for fixing other members are fixed to the body of the EGR cooler 40 by welding.

As shown in FIGS. 10 and 12, the EGR valve 43 has a roughly tubular shape, and as shown in FIGS. 4 and 5, the EGR valve 43 is arranged in a long posture in the front-rear direction (crank axis direction). , In the side view of FIGS. 4 and 5, the intake manifold 3 is tilted with respect to the horizontal so as to become lower as the distance from the intake manifold 3 increases. That is, the EGR valve 43 is in a posture close to horizontal so that the end connected to the EGR cooler 40 is lowered.

As shown in FIG. 13A, a flange portion 53 is formed at one end (rear end) of the EGR valve 43, and the flange portion 53 is fixed to the upper flange 47a of the EGR cooler 40. An inlet hole 54 through which EGR gas flows is opened downward in the central portion of the flange portion 53. As shown in FIG. 12, a fastening seat surface 55 exposed sideways (leftward) is formed in a portion of the EGR valve 43 closer to the flange portion 53, and the EGR gas outlet hole 56 is formed in the fastening seat surface 55. Is open sideways (to the left).

The starting end of the second portion 45 on the downstream side of the EGR passage is fixed to the fastening seat surface 55 of the EGR valve 43 via the flange 57. The flange 57 is fixed with two bolts, and two tap holes 58 to which the bolts are screwed are formed on the fastening seat surface 55 in order to fix the flange 57 of the second portion 45 on the downstream side of the EGR passage. ing.

A control unit 59 provided with an actuator such as an electromagnetic solenoid is provided at the other end (front end) of the EGR valve 43. By operating a valve body such as a needle valve by the control unit 59, the discharge amount of EGR gas is controlled. A connector 60 for connecting a cable is provided laterally in the control unit 59. Further, the EGR valve 43 is a water-cooled type, and an inflow port 61 and an outflow port 62 for cooling water are provided on the upper surface thereof, and the inflow port 61 for cooling water is a port 50 for the EGR valve provided in the EGR cooler 40. It is connected by a pipe 50a to the EGR valve. The inflow port 61 and the outflow port 62 of the cooling water may be arranged in the opposite direction.

As described above, the second portion 45 on the downstream side of the EGR passage is inclined so as to be lowered toward the downstream end in the side view of FIGS. 4 and 5. Further, as shown in FIG. 7, even in the rear view, it is inclined so as to be lowered toward the downstream end. Further, a flange 63 is provided at the downstream end of the second portion 45 on the downstream side of the EGR passage, and the flange 63 is fixed to the rear end of the EGR distribution passage 46 with bolts (stud bolts) and nuts.

For example, as can be easily understood from FIG. 3, the EGR distribution passage 46 has an anteroposterior longitudinal trunk passage 64 and three branch passages 65 branched from the trunk passage 64, and has a rear end portion of the trunk passage 64. While the downstream end of the second portion 45 on the downstream side of the EGR passage is connected to the EGR passage, each branch passage 65 is connected to the downstream portion of the branch pipe 29 from above. Although the branch passage 65 is bolted to the branch pipe 29 of the intake manifold 3, the EGR distribution passage 46 may be made of resin and welded to the intake manifold 3.

(4). Bracket supporting the EGR valve As can be easily understood from FIG. 8, the EGR cooler 40 and the EGR valve 43 are roughly arranged above the cooling water distribution unit 14 formed at the rear of the cylinder head 2. Of the four corners of the cylinder head 2, they are arranged in the vicinity of the first corner portion 68, which is the connecting portion between the intake side longitudinal wall 7 and the rear wall 10. Then, the EGR valve 43 is fixed to a metal plate bracket 69 fixed to the upper surface of the first corner portion 68 with a stud bolt 70 and a nut (see FIG. 12).

As shown in FIGS. 12 and 13, the bracket 69 is provided from the bottom plate 73 fixed to the upper surface of the first corner portion 68 of the cylinder head 2 with stud bolts 71 and nuts, the first side plate 74 rising from the bottom plate 73, and the bottom plate 73. It has a second side plate 75 that stands up and is connected to the first side plate 74. The first side plate 74 and the second side plate 75 intersect in an L shape, and the lower end of the fastening seat surface 55 of the EGR valve 43 is fixed to the upper end of the first side plate 74 with a bolt 76 (see FIG. 12). Has been done. Therefore, a bolt insertion hole 77 is formed in the upper end portion of the first side plate 74, and a tap hole 78 is formed in the lower end portion of the fastening seat surface 55 of the EGR valve 43.

The first side plate 74 spreads substantially in the front-rear direction, and the second side plate 75 spreads substantially in the left-right direction. This is consistent with the fact that the EGR valve 43 is in a generally long posture in the front-rear direction. A forward overhanging portion 74a is formed at a midway height position of the first side plate 74, and an auxiliary bracket 79 for attaching another member is fixed to the forward overhanging portion 74a by welding.

Further, the vertically elongated reinforcing rib plate 80 is fixed by welding to the left side surface of the first side plate 74 facing the side opposite to the second side plate 75. The reinforcing rib plate 80 is thicker than the bracket 69, and its end face overlaps with the first side plate 74. Further, a notch 81 opened toward the first side plate 74 is formed in the upper and lower middle portions of the reinforcing rib plate 80, and the portion above the notch 81 is a portion of the forward overhanging portion 64a. It is welded to the first side plate 74, and the portion below the notch 81 is welded to the edge portion of the first side plate 74.

As described with reference to FIG. 6, the intake unit 22 extends over a wide area and covers most of the engine body, but as is shown in FIG. 6, the EGR valve 43 and the EGR cooler 40 take intake air. Not covered by unit 22. That is, the EGR valve 43 and the EGR cooler 40 are arranged at the entrance corner formed by the air cleaner 23 and the intake duct 24. In FIG. 4, the hood (bonnet) 82 covering the engine room is schematically shown by a alternate long and short dash line.

(5). Summary In this embodiment, since the EGR cooler 40 is arranged near the first corner portion 68 of the cylinder head 2, the EGR feed port 18 of the cooling water distribution portion 14 and the cooling water inlet of the EGR cooler 40 The length of the EGR feed pipe 49a connecting to the port 48a is short. Therefore, it can contribute to the weight reduction of the internal combustion engine. Further, since the EGR feed port 18 is a dedicated port to the EGR cooler 40, it is possible to reliably feed the cooling water to the EGR cooler 40. Therefore, the required flow rate can be secured by the EGR cooler, and the EGR gas can be cooled firmly.

Then, in the connection step of the EGR feed pipe 49a, one end is fitted into one port against elasticity, then the EGR feed pipe 49a is bent and deformed, and the other end is fitted into the other port against elasticity. However, if the length of the EGR feed pipe 49a is short, the postures of the EGR feed port 18 of the cooling water distribution unit 14 and the cooling water inlet port 48a of the EGR cooler 40 are significantly different. When fitting into one port and then deforming and fitting the other end into the other port, it is difficult to bend and deform the EGR feed pipe 49a, and it is difficult to apply force to the EGR feed pipe 49a, so connection work (EGR feed pipe) (Handling of 49a) may be troublesome.

On the other hand, in the present embodiment, since the two ports 18, 48a are open in the same direction, the EGR feed pipe 49a need only be bent into a simple U shape. Therefore, even if the EGR feed pipe 49a is short, it can be easily bent by bending and deforming and fitting the other end into the other port, and the other end is firmly held by the other end of the EGR feed pipe 49a. It can be inserted into the port with a strong force. Therefore, the connection work of the EGR feed pipe 49a can be performed efficiently and reliably.

The internal combustion engine is assembled as one unit on the factory line and then mounted in the engine room of the vehicle. When assembling the internal combustion engine, the rear side of the cooling water distribution unit 14 is an open space. Therefore, if the EGR feed port 18 and the cooling water inlet port 48a are opened rearward of the engine as in the present embodiment, the EGR feed pipe 49a can be connected without any obstacles, which further enhances the ease of work. There is an advantage that it can be increased.

Further, in the embodiment, the cooling water outlet port 48b of the EGR cooler 40 is also opened backward, but with such a configuration, there is an advantage that the EGR return pipe 49b can be easily fitted into the cooling water outlet port 48b. be.

As described with reference to FIG. 8, in the present embodiment, it is arranged outside the first corner portion 68 of the cylinder head 2 of the EGR cooler 40. Therefore, the EGR cooler 40 does not interfere with the pipes connected to the cooling water distribution unit 14. Further, since the EGR feed port 18 of the cooling water distribution unit 14 is also formed at the position of the first corner portion 68, it contributes to shortening the EGR feed pipe 49a.

In the present embodiment, since the EGR valve 43 is arranged at the highest position of the EGR passage, even if the EGR valve 43 is closed, the condensed water generated in the EGR passage is on the upstream side and the downstream side of the EGR valve 43. It also flows downward. Therefore, the problem of corrosion and the problem of freezing due to the accumulation of condensed water can be solved.

In the present embodiment, as clearly shown in FIGS. 4 and 5, the EGR cooler 40 is inclined so as to move away from the intake manifold 3 as it goes upward in the side view. Therefore, it is possible to prevent the EGR cooler 40 from hitting the head cover. In other words, the EGR cooler 40 can be arranged in a vertical position without hitting the head cover.

The invention of the present application can be embodied in various ways other than the above. For example, the EGR feed port 18 and the cooling water inlet port 48a are provided with straight type joint pipes, but they can also be configured with L-shaped or doglegged joint pipes.

The invention of the present application can be embodied in an internal combustion engine. Therefore, it can be used industrially.

1 Cylinder block that constitutes the main body of the engine 2 Cylinder head that constitutes the main body of the engine 3 Intake manifold 14 Cooling water distribution section 18 EGR feed port 35 Catalyst case 36 EGR passage upstream part 37 EGR internal passage 40 EGR cooler 41 Joint pipe 43 EGR valve 45 EGR passage downstream second part 46 EGR distribution passage 48a EGR cooler cooling water inlet port 48b EGR cooler cooling water outlet port 49a EGR feed pipe 49b EGR return pipe

Claims (1)

Equipped with a cylinder head and a water-cooled EGR cooler,
Cooling water having a tubular EGR feed port that sends cooling water to the EGR cooler projecting backward in the direction opposite to the timing chain at the rear end of the cylinder head on the side opposite to the timing chain arrangement portion. While a distribution unit is provided,
The EGR cooler has a tubular cooling water inlet port connected to the EGR feed port via a cooling water feed pipe, and a tubular cooling water outlet port to which a cooling water return pipe is connected. The cooling water inlet port and the cooling water outlet port are arranged on the outside of the cooling water distribution unit in a state of protruding backward .
The cooling water inlet port of the EGR cooler is inclined toward the EGR feed port as it goes backward.
Internal combustion engine.

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