Internal combustion engine

Abstract

An internal combustion engine includes a cylinder block, an intake passage, a supercharger, an exhaust purification device, an exhaust circulation passage, an exhaust circulation valve disposed on the exhaust circulation passage so as to be displaced with respect to the exhaust purification device in a direction of extension of a crankshaft, and a cooling device disposed on the exhaust circulation passage to cool exhaust circulation gas flowing through the exhaust circulation passage with a coolant. One side of the cooling device is disposed between the exhaust purification device and the cylinder block, and the other side of the cooling device is disposed in a space surrounded by the supercharger, the exhaust purification device, and the exhaust circulation valve.

Description

Technical Field

[0001] This disclosure relates to an internal combustion engine having an exhaust recirculation device. Background Technology

[0002] Conventionally, internal combustion engines with an exhaust recirculation device that recirculates a portion of the exhaust gas discharged from the internal combustion engine into the intake air as exhaust recirculation gas are known (for example, see Patent Document 1). In the internal combustion engine of Patent Document 1, a portion of the exhaust gas discharged from the cylinder and passing through the exhaust purification device is introduced into the intake air.

[0003] Furthermore, the internal combustion engine in Patent Document 1 includes a cooling device for cooling the exhaust gas recirculation. In the exhaust purification device of Patent Document 1, the cooling device is cooled by a coolant, and the exhaust gas recirculation is introduced into the intake air while the temperature is lowered. Additionally, in the exhaust purification device of Patent Document 1, the cooling device is compactly positioned below the exhaust manifold.

[0004] Existing technology

[0005] Patent documents

[0006] [Patent Document 1] International Publication No. 2012 / 056885 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] However, in the internal combustion engine of Patent Document 1, the cooling device surrounds the cylinder block and exhaust purification device in the front-to-back direction, and is positioned above a space surrounding the exhaust manifold. In such a space, the airflow towards the internal combustion engine is difficult to expel. Therefore, heat released from the exhaust manifold and exhaust purification device tends to remain in the space. Consequently, the coolant flowing through the cooling device is easily heated. If the coolant is heated, the temperature of the exhaust gas recirculation rises, and the intake air temperature tends to rise as well.

[0009] The purpose of this disclosure is to provide an internal combustion engine capable of suppressing overheating of the cooling system.

[0010] The disclosed internal combustion engine includes a cylinder block, an intake manifold, a turbocharger, an exhaust gas purification device, an exhaust gas recirculation passage, an exhaust gas recirculation valve, and a cooling device. The cylinder block forms the cylinder and holds the crankshaft. The intake manifold supplies intake air to the cylinder. The turbocharger pressurizes the intake air flowing through the intake manifold. The exhaust gas purification device is displaced relative to the turbocharger in the crankshaft extension direction and extends in the cylinder extension direction. The exhaust gas recirculation passage connects to the intake manifold downstream of the exhaust gas purification device. The exhaust gas recirculation valve is displaced on the exhaust gas recirculation passage relative to the exhaust gas purification device in the crankshaft extension direction. The cooling device is disposed on the exhaust gas recirculation passage and cools the exhaust gas flowing through the exhaust gas recirculation passage with coolant. One side of the cooling device is disposed between the exhaust gas purification device and the cylinder block, and the other side of the cooling device is disposed in the space surrounded by the turbocharger, the exhaust gas purification device, and the exhaust gas recirculation valve.

[0011] According to this internal combustion engine, since one side of the cooling device is located between the cylinder block and the exhaust gas purification device, the coolant is easily heated. Therefore, for example, during a cold start of the internal combustion engine, the temperature of the cooled coolant is easily raised. As a result, the engine warm-up is easily promoted. On the other hand, since the other side of the cooling device is located in the space between the turbocharger, exhaust gas recirculation valve, and exhaust gas purification device, heat escapes from this space. Therefore, for example, when the internal combustion engine temperature is high, overheating of the cooling device can be suppressed.

[0012] An internal combustion engine can be installed in a vehicle. The vehicle's power transmission system can also be positioned below the cooling system.

[0013] According to this structure, since flying debris from below the vehicle is directed toward the relatively robust power transmission device, damage to the cooling system can be suppressed.

[0014] The cooling device can be configured at an angle so that it is close to the cylinder block as it approaches the exhaust purification device.

[0015] According to this structure, the cooling device can be configured compactly. Furthermore, with such a configuration, since the cooling device is arranged along the exhaust purification device, the temperature of the cooled coolant can easily rise, for example, during a cold start of the internal combustion engine.

[0016] The internal combustion engine can also be further equipped with a coolant supply passage for supplying coolant to the cooling system. The coolant supply passage can also be located between the exhaust purification device and the cooling system.

[0017] This structure makes it easy for the temperature of the coolant flowing through the coolant supply passage to rise. Therefore, for example, during a cold start of an internal combustion engine, the temperature of the cooled coolant is easily raised.

[0018] The exhaust recirculation passage can also be configured to slope downwards as it approaches the exhaust purification device from the intake passage.

[0019] This structure can prevent condensate from flowing into the air intake channel.

[0020] An internal combustion engine can be installed in a vehicle. The vehicle can have a heater system to heat the passenger compartment. Coolant can also flow to the heater system after passing through the cooling system.

[0021] This structure improves the performance of the vehicle's heater.

[0022] Invention Effects

[0023] According to this disclosure, it is possible to provide an internal combustion engine that can suppress overheating of the cooling device. Attached Figure Description

[0024] Figure 1 This is a conceptual diagram of a vehicle installation state of an internal combustion engine according to an embodiment of the present disclosure.

[0025] Figure 2 This is a rear view of an internal combustion engine according to an embodiment of the present disclosure.

[0026] Figure 3 yes Figure 2 Section IV-IV.

[0027] Figure 4 yes Figure 2 VV cross-sectional diagram.

[0028] Figure 5 This is a schematic diagram of an intake pipe connector according to an embodiment of the present disclosure.

[0029] Figure 6 This is a cross-sectional view near the center of the through hole of the intake pipe connector according to an embodiment of the present disclosure.

[0030] [Symbol Explanation]

[0031] 1: Internal combustion engine

[0032] 2: Cylinder block

[0033] 2a: Cylinder

[0034] 2b: Crankshaft

[0035] 6: Air intake channel

[0036] 8: Turbocharger

[0037] 10: Exhaust gas purification device

[0038] 12: Exhaust recirculation channel

[0039] 14: Exhaust recirculation valve

[0040] 16: Cooling device

[0041] 16a: Entrance side

[0042] 16b: Export side

[0043] 18: Coolant supply channel

[0044] 22: Differential gearbox (an example of a power transmission device)

[0045] 24: Heater device

[0046] C: Vehicle

[0047] G: Up and down direction (direction for cylinder 2a extension)

[0048] P: Vehicle width direction (crankshaft 2b extension setting direction)

[0049] Q: Front and back directions

[0050] S: Space Detailed Implementation

[0051] Hereinafter, an embodiment of the present disclosure will be described with reference to the accompanying drawings. It should be noted that in the following description, the longitudinal direction of the vehicle is denoted as Q, and the front direction as F. Furthermore, the width direction of the vehicle is denoted as P, and the right side viewed from the rear of the vehicle is denoted as R. Further, the vertical direction of the vehicle is denoted as G, and the top direction as U.

[0052] like Figure 1 and Figure 2 As shown, the internal combustion engine 1 includes a cylinder block 2, a cylinder head 4, an intake passage 6, a turbocharger 8, an exhaust purification device 10, an exhaust circulation passage 12, an exhaust circulation valve 14, a cooling device 16, a coolant supply passage 18, and a coolant discharge passage 20.

[0053] In this embodiment, the internal combustion engine 1 is an inline 4-cylinder internal combustion engine 1 formed by four cylinders 2a connected in series on the cylinder block 2. A crankshaft 2b extends from the internal combustion engine 1 in the direction in which the cylinders 2a are arranged. The crankshaft 2b is held on the cylinder block 2. However, the type and arrangement direction of the internal combustion engine 1 are not limited to an inline type; for example, it can also be a horizontally opposed type or a V-type.

[0054] An internal combustion engine 1 is mounted on a vehicle C. The vehicle C includes a transmission 21, a differential gearbox (an example of a power transmission device) 22, and a heater device 24. The transmission 21 changes the speed of the power from the internal combustion engine 1 and transmits it to the differential gearbox 22. The differential gearbox 22 reduces the speed of the power transmitted from the transmission 21 and drives the wheels W via the drive shaft 26. The heater device 24 is a device that uses the heat from the coolant flowing into the internal combustion engine 1 to heat the interior of the vehicle C. In this embodiment, the heater device 24 is located behind the front bulkhead (not shown) of the vehicle C.

[0055] It should be noted that when the internal combustion engine 1 is cold-started, the coolant is heated through the internal combustion engine 1 and the cooling device 16. The heated coolant warms up the internal combustion engine 1 and heats the vehicle interior through the heater device 24.

[0056] On the other hand, after the internal combustion engine 1 has warmed up, the thermostat (not shown) opens, and coolant is supplied to the radiator (not shown) to cool the coolant. The coolant in the radiator cools the internal combustion engine 1 and supplies it to the cooling device 16 to cool the exhaust gas recirculation gas (described later).

[0057] In this embodiment, the internal combustion engine 1 is positioned relative to the vehicle C with the crankshaft 2b extending in the direction of extension (hereinafter referred to as the crankshaft 2b extension direction) in the vehicle width direction P of the vehicle C. The transmission 21 is positioned to the left of the internal combustion engine 1 in the vehicle width direction P. The differential gearbox 22 is formed into a relatively robust structure using die casting aluminum or the like, and is positioned to the right R of the transmission 21 in the vehicle width direction P. That is, the vehicle C in this embodiment is a front-wheel drive configuration with a transversely mounted internal combustion engine 1.

[0058] The cylinder head 4 is disposed on the upper part of the cylinder block 2. The cylinder head 4 has an intake port for supplying intake air to the cylinders 2a. The intake passage 6 is connected to the intake port via an intake manifold (not shown), an intercooler (not shown), and a turbocharger 8. In this embodiment, the exhaust collection section 4a, which collects the exhaust from the four cylinders 2a, is integrally formed inside the cylinder head 4 (see reference). Figure 3 ).

[0059] The intake passage 6 has a bend 6h. The bend 6h is formed into a bend shape by an intake pipe connector 6a. The intake pipe connector 6a is formed into a cylindrical shape by a metal component such as aluminum, and the intake passage 6 is formed inside. In this embodiment, the intake pipe connector 6a is formed into a bend shape from the top U of the vehicle C toward the right side R in the vehicle width direction P. With this shape, the intake pipe connector 6a extends from the front F side of the vehicle toward the rear, and smoothly connects to the intake passage 6, which changes direction downward in the rear direction of the internal combustion engine 1, and the inlet of the compressor 8b, which will be described later. In addition, the intake pipe connector 6a has a through hole 6c that penetrates the wall of the intake passage 6, which functions as an inlet for introducing exhaust gas recirculated through the inside of the pipe connector 6b of the exhaust recirculation passage 12 into the intake passage 6.

[0060] In this intake pipe joint 6a, the pressure of the intake air flowing outside the bend 6h is high, while the pressure of the intake air flowing inside the bend 6h is low. Furthermore, due to the rotation of the compressor 8b (described later), a swirling flow along the rotation direction of the compressor 8b is easily generated in the intake passage 6 formed in the intake pipe joint 6a. More specifically, the intake air flowing in the intake passage 6 upstream of the compressor 8b is dragged along the rotation direction of the compressor 8b while simultaneously generating a swirling flow along the rotation direction of the compressor 8b. Therefore, condensate flowing into the intake passage 6 is centrifugally separated by the swirling flow and easily disperses towards the inner circumference X of the intake passage 6.

[0061] The turbocharger 8 has a turbine 8a and a compressor 8b coaxially arranged with the turbine 8a. For example... Figure 3 As shown, the turbine 8a is fixed to the outlet flange 4b ​​of the exhaust manifold 4a. In this embodiment, the turbine 8a is installed such that exhaust flows upward from the outlet flange 4b. In this way, by configuring the turbine 8a, the turbine 8a is easily cooled by the driving airflow passing between the engine hood covering the engine compartment housing the internal combustion engine 1 and the internal combustion engine 1.

[0062] Compressor 8b is located on intake passage 6 and rotates counterclockwise when viewed from the transmission 21 side (reference). Figure 6 The upstream side of the compressor 8b is connected to the intake passage 6 via an intake pipe connector 6a that extends from the top U through the bend 6h and extends toward the crankshaft 2b in a direction (in this embodiment, the vehicle width direction P). In the turbocharger 8, the turbine 8a rotates by the exhaust gas flowing from the exhaust gas collection section 4a, thereby rotating the compressor 8b and pressurizing the intake air flowing through the intake passage 6.

[0063] like Figure 2As shown, the exhaust purification device 10 is disposed displaced on the front side (in this embodiment, the right side in the vehicle width direction P) relative to the direction in which the turbocharger 8 extends toward the crankshaft 2b. It should be noted that the side of the crankshaft 2b that is connected to the transmission 21 is generally referred to as the rear side, and the opposite side as the front side. Therefore, in this embodiment, the front side viewed from the direction in which the crankshaft 2b extends aligns with the right side in the vehicle width direction P, and the rear side viewed from the direction in which the crankshaft 2b extends aligns with the left side in the vehicle width direction P.

[0064] An exhaust purification device 10 is located downstream of the turbine 8a to purify the exhaust gas. In this embodiment, the exhaust purification device 10 includes a catalyst section 10a, an inlet pipe 10b, and an outlet pipe 10c. The catalyst section 10a is formed by inserting a honeycomb carrier coated with a three-way catalyst for purifying carbon monoxide and the like emitted from the cylinder 2a into a metal tubular component. In the case of a cold start of the internal combustion engine 1, the catalyst section 10a is controlled to a high temperature.

[0065] In the exhaust purification device 10, the catalyst section 10a extends in the extending direction of the cylinder 2a (hereinafter referred to as the cylinder 2a extending direction). In this embodiment, the cylinder 2a extending direction of the cylinder block 2 is arranged along the vertical direction G of the vehicle C. Therefore, in this embodiment, the cylinder 2a extending direction is approximately consistent with the vertical direction G. It should be noted that the cylinder block 2 may also be arranged slightly inclined above the cylinder 2a and behind the vehicle C (see reference). Figure 3 In this embodiment, the inlet pipe 10b of the exhaust purification device 10 is positioned to the right R of the turbine 8a in the vehicle width direction P (viewed from the direction of extension of the crankshaft 2b as the front side). The inlet pipe 10b bends downward and connects to the catalyst section 10a. The catalyst section 10a is offset to the right of the turbine 8a via the inlet pipe 10b. The outlet pipe 10c connects to the lower part of the catalyst section 10a, bends to the left, and extends towards the rear of the vehicle. A heat protector made of a plate-shaped metal component with a shape consistent with the exhaust purification device 10 may also be provided around the exhaust purification device 10.

[0066] The internal combustion engine 1 includes an exhaust gas recirculation passage 12, an exhaust gas recirculation valve 14, and a cooling device 16, thereby constituting an exhaust gas recirculation device. The exhaust gas recirculation device is configured to recirculate a portion of the exhaust gas discharged from cylinder 2a back into the intake air as exhaust gas recirculation gas, thereby re-burning the exhaust gas. The internal combustion engine 1 reduces nitrogen oxides by re-burning the exhaust gas, thus improving the fuel economy of the vehicle C. In this embodiment, the exhaust gas recirculation device is a low-pressure type where the exhaust gas recirculation passage 12 connects downstream of the exhaust gas purification device 10 to upstream of the compressor 8b in the intake passage 6. However, the exhaust gas recirculation device is not limited to this; it could also be a high-pressure type where the exhaust gas recirculation passage 12 connects downstream of the compressor 8b. It should be noted that exhaust gas recirculation is sometimes abbreviated as EGR (Exhaust Gas Recirculation).

[0067] The exhaust recirculation passage 12 extends downward from the intake passage 6 and bends to the right (R) towards the exhaust purification device 10. The exhaust recirculation passage 12 passes between the exhaust purification device 10 and the cylinder block 2, and connects to the outlet pipe 10c of the exhaust purification device 10 (see reference). Figure 4 The exhaust recirculation passage 12 slopes downwards from the intake passage 6 toward the outlet pipe 10c, toward the exhaust purification device 10. That is, the exhaust recirculation passage 12 slopes downwards toward the right R. Accordingly, the condensate generated by the exhaust recirculation gas being cooled by the cooling device 16 flows downwards due to its own weight, which can prevent the condensate from flowing into the intake passage 6.

[0068] In this embodiment, such as Figure 5 As shown, the exhaust recirculation passage 12 is connected to the intake passage 6 via a circularly shaped connecting pipe 6b extending downwards from the intake pipe connector 6a. Additionally, as... Figure 2 As shown, the exhaust circulation passage 12 has a first passage 12a from the pipe 6b to the exhaust circulation valve 14, a second passage 12b from the exhaust circulation valve 14 to the cooling device 16, a third passage 12c through the cooling device, and a fourth passage 12d from the cooling device 16 to the outlet pipe 10c. The first passage 12a, the second passage 12b, the third passage 12c, and the fourth passage 12d are all pipes with circular cross-sections.

[0069] The first channel 12a is formed by a rubber hose and a metal connector mounted on the exhaust recirculation valve 14. The second channel 12b is formed by a metal component such as aluminum. The third channel 12c, from the inlet flange 16c of the cooling device 16 to the outlet side 16b of the cooling device 16 (described later), is formed by a stainless steel channel, around which the cooling device 16 is arranged. The fourth channel 12d is formed by a stainless steel pipe. The exhaust recirculation gas enters the fourth channel 12d from the outlet pipe 10c of the exhaust purification device 10, and flows into the intake channel 6 in the order of the third channel 12c, the second channel 12b, the first channel 12a, and the connector 6b.

[0070] like Figure 6 As shown, the exhaust recirculation channel 12 extends downward from the through hole 6c along the tangent TL direction of the inner circumference X of the intake channel 6. Furthermore, the exhaust recirculation channel 12 is offset (displaced) relative to the intake channel 6 in a direction orthogonal to the extending direction of the intake channel 6 (in this embodiment, either the vertical direction G or the horizontal direction Q, or an inclined direction between the vertical direction G and the horizontal direction Q). Thus, by extending along the tangent TL direction and being offset in a direction orthogonal to the extending direction of the intake channel 6, the condensate separated by centrifugal force through the swirling flow generated in the intake channel 6 is easily pushed back into the exhaust recirculation channel 12.

[0071] like Figure 5 As shown, the exhaust recirculation passage 12 extends outward from the bend 6h. More specifically, at least a portion of the through hole 6c to which the fitting 6b of the exhaust recirculation passage 12 is connected is disposed near the lower end of the bend 6h (see reference). Figure 2 The exhaust recirculation passage 12 extends radially outward (in this embodiment, the lower side) towards the portion that bends downward from the through hole 6c and to the right (R-shaped) from the top of the bend 6h. Thus, by extending the exhaust recirculation passage 12 outward from the bend 6h, the pressure of the intake air flowing outside the intake passage 6 formed within the bend 6h easily pushes condensate back into the exhaust recirculation passage 12. As a result, it is easy to suppress the inflow of condensate into the intake passage 6. Furthermore, even if condensate flows into the intake passage 6, it is easily pushed back from the intake passage 6 into the exhaust recirculation passage 12.

[0072] Furthermore, the exhaust recirculation passage 12 is connected upstream of the intake passage at an acute angle to it. More specifically, as... Figure 2As shown, the angle α between the central line of the intake passage (refer to the double-dotted line Oa), which is an imaginary line passing approximately the center of the intake passage 6, and the central line of the exhaust recirculation passage (refer to the double-dotted line Oe), which is an imaginary line passing approximately the center of the first passage 12a of the exhaust recirculation passage 12, is an acute angle. Accordingly, the exhaust recirculation passage 12 is connected to the intake passage 6 in the opposite direction of the intake air flow, and the exhaust recirculation gas flowing through the exhaust recirculation passage 12 is introduced at an acute angle in the opposite direction to the intake air flow through the intake passage 6. Therefore, condensate, which is heavier than the exhaust recirculation gas contained in the exhaust recirculation gas, is easily affected by the intake air pressure flowing through the intake passage 6. As a result, the condensate contained in the exhaust recirculation gas is easily pushed back into the exhaust recirculation passage 12.

[0073] like Figure 6 As shown, the nozzle 6b of the exhaust recirculation passage 12 has an extension 6d extending straight down and a curved section 6e connecting the extension 6d to the through hole 6c. That is, in Figure 6 In cross-sectional view, the exhaust recirculation passage 12 is configured such that the inner circumferential surface 6f of the extension 6d located at the front side F in the longitudinal direction Q does not intersect with the inner circumferential surface 6g of the intake passage 6. The exhaust recirculation passage 12 smoothly connects from the extension 6d to the through hole 6c via the bend 6e, without significant change in inner diameter. Furthermore, the exhaust recirculation passage 12 does not protrude into the intake passage 6 but connects to the through hole 6c. With this configuration of the exhaust recirculation passage 12, even if condensate flows into the intake passage 6, the condensate can easily return to the exhaust recirculation passage 12. In this embodiment, the exhaust recirculation passage 12 is offset relative to the intake passage 6 on the cylinder block 2 side (in this embodiment, the front side F of the longitudinal direction Q of the vehicle C). Accordingly, the connecting pipe 6b is compactly accommodated behind the internal combustion engine 1 without protruding. Furthermore, it is also easy to ensure the distance between the internal combustion engine 1 and the front bulkhead (not shown) of the vehicle C, improving the safety of the vehicle C in the event of a collision.

[0074] Furthermore, when the exhaust gas passes through the bend 6e, condensate, which is heavier than the exhaust gas, is centrifugally separated and collides with the upper part of the inner circumferential surface of the bend 6e. The condensate that collides with the upper part of the inner circumferential surface of the bend 6e falls down along the inner circumferential surface of the bend 6e by its own weight, toward the exhaust gas recirculation valve 14. Accordingly, it is possible to prevent condensate from flowing into the intake passage 6.

[0075] Furthermore, the bend 6e bends along the rotation direction of the compressor 8b of the turbocharger 8. Therefore, the condensate separated by the centrifugal swirling flow easily flows into the inlet 6b of the exhaust circulation passage 12. Accordingly, the condensate easily returns to the exhaust circulation passage 12.

[0076] Exhaust recirculation valve 14 is disposed on exhaust recirculation passage 12. Exhaust recirculation valve 14 is provided for adjusting the amount of exhaust gas recirculated into intake passage 6. Exhaust recirculation valve 14 is disposed below turbocharger 8, and is disposed side by side with exhaust purification device 10 and crankshaft 2b in the direction of extension (in this embodiment, vehicle width direction P).

[0077] The cooling device 16 is disposed on the exhaust circulation channel 12 and is a heat exchanger that cools the exhaust gas flowing through the exhaust circulation channel 12 with coolant. In this embodiment, the cooling device 16 is formed of a prism-shaped metal component such as stainless steel with a channel through which coolant flows, including an inlet side 16a and an outlet side 16b. The cooling device 16 covers the periphery of the third channel 12c and cools the exhaust gas by flowing coolant around the third channel 12c. In this embodiment, the cooling device 16 is welded to the third channel 12c and is integrally formed from the inlet flange 16c to the outlet side 16b.

[0078] like Figure 2 , Figure 3 as well as Figure 4 As shown, the cooling device 16 is positioned along the vehicle width direction P in its longitudinal direction and is fixed to the cylinder block 2. The cooling device 16 is positioned at an angle so that its inlet side 16a approaches the cylinder block 2 as it gets closer to the exhaust purification device 10. That is, the cooling device 16 is positioned at an angle in the longitudinal direction Q so that the inlet side 16a is F ahead of the outlet side 16b in the longitudinal direction Q.

[0079] A portion of the inlet side 16a of the cooling device 16 is disposed between the exhaust purification device 10 and the cylinder block 2, and a portion of the outlet side 16b is disposed in the space S surrounded by the turbocharger 8, the exhaust purification device 10, and the exhaust recirculation valve 14 when viewed from the rear of the vehicle C (viewed from the exhaust side of the internal combustion engine 1). From this space S, the driving air passing between the top of the internal combustion engine 1 and the engine hood (not shown) of the vehicle C passes through the turbine 8a. Heat from the exhaust purification device 10 is also carried away with the driving air. That is, the space S is part of a cooling passage using the driving air. The driving air passing through the space S passes behind the differential gearbox 22 and through the lower part of the vehicle C. Specifically, in the internal combustion engine 1 of this embodiment, the exhaust manifold 4a is integrally formed with the cylinder head 4, and the outlet of the exhaust manifold 4a is connected to the turbine 8a. Furthermore, the exhaust purification device 10 is disposed offset to the front of the turbocharger 8 in the direction extending towards the crankshaft 2b (to the right in the vehicle width direction P in this embodiment). Accordingly, by using an exhaust manifold instead of an exhaust collection section 4a, compared to an internal combustion engine (e.g., the internal combustion engine of Patent Document 1) in which the exhaust purification device 10 is mounted without offset relative to the exhaust manifold in the direction of extension of the crankshaft 2b, the driving airflow is more likely to flow in the space S below the turbocharger 8.

[0080] By configuring the cooling device 16 in this way, it can be arranged compactly. Furthermore, during a cold start of the internal combustion engine 1, the coolant flowing through the cooling device 16 is in a cooled state. However, since the cooling device 16 is arranged along the curved surface of the exhaust purification device 10, the coolant is heated from the exhaust purification device 10, and its temperature easily rises. On the other hand, since the outlet side 16b of the cooling device 16 is located in space S, after the internal combustion engine 1 has warmed up, it is cooled by the driving airflow while the vehicle C is in motion, thus preventing overheating of the cooling device 16.

[0081] Furthermore, the cooling device 16 is arranged in the order of exhaust recirculation valve 14, cooling device 16, and exhaust purification device 10, extending along the crankshaft 2b (in this embodiment, the same direction as the vehicle width direction P). That is, the cooling device 16 is positioned between the exhaust recirculation valve 14 and the exhaust purification device 10 in the rear view of vehicle C. Since the cooling device 16 is cooled by coolant, the heat released from the exhaust purification device 10 is isolated by the cooling device 16. As a result, the temperature rise around the exhaust recirculation valve 14 can be suppressed.

[0082] Below the cooling device 16 is a differential gearbox 22, which serves as an example of a power transmission device. Accordingly, flying debris such as stones scattered from below the vehicle C impacts the differential gearbox 22. Therefore, damage to the cooling device 16 by flying debris can be prevented.

[0083] like Figure 4 As shown, the coolant supply channel 18 branches off from the heat box 4c installed on the cylinder head 4 and connects to the cooling device 16, supplying coolant to the cooling device 16. Figure 2 , Figure 3 as well as Figure 4 As shown, the coolant supply passage 18 extends forward from the right side of the exhaust recirculation valve 14, passing behind it. This forward-extending coolant supply passage 18 connects to a pipe disposed near the inlet side 16a of the cooling device 16, between the cooling device 16 and the exhaust purification device 10. During a cold start of the internal combustion engine 1, cooled coolant flows through the coolant supply passage 18. However, this configuration of the coolant supply passage 18 allows the coolant to easily become heated by the exhaust purification device 10.

[0084] like Figure 1 As shown, the coolant discharge passage 20 connects to the heater assembly 24 near the outlet side 16b of the cooling device 16. That is, in the case of a cold start of the internal combustion engine 1, the coolant is heated by the heat from the exhaust gas purification device 10 and flows to the heater assembly 24. Accordingly, the heater assembly 24 easily obtains heat from the coolant, and the time required to warm the vehicle interior is shortened. That is, the heater performance is improved. In particular, in this embodiment, the turbocharger 8 is a turbocharger type with a turbine 8a. Thus, in the turbocharger 8, the turbine 8a has a large heat capacity, and the turbine 8a draws away heat from the internal combustion engine 1 during startup, which can easily degrade the heater performance. However, according to this embodiment, the internal combustion engine 1 is heated by the exhaust gas purification device 10 through the cooling device 16, which easily improves the heater performance.

[0085] Furthermore, due to the increasing restrictions on fuel consumption in recent years, the amount of exhaust gas introduced into the intake passage 6 has been continuously increasing. Particularly in the internal combustion engine 1 of this embodiment, since it has a turbocharger 8, more exhaust gas can be introduced into the intake passage 6 upstream of the turbocharger 8 compared to introducing it downstream. However, with a large amount of exhaust gas introduced into the intake, cooling is necessary to prevent the intake temperature from rising. Cooling the exhaust gas can easily lead to condensation. Furthermore, if condensation adheres to the compressor 8b, it can easily cause turbocharger 8 malfunction. In the internal combustion engine 1 of this embodiment, since the outflow of condensation into the intake passage 6 can be suppressed, the adhesion of condensation to the compressor 8b is easily prevented.

[0086] Furthermore, if the amount of exhaust gas introduced increases, the pressure loss due to the narrowing of the inner diameter of the exhaust recirculation passage 12 also increases. If the pressure loss increases, it becomes difficult for the exhaust gas to be introduced into the intake passage 6. However, in the internal combustion engine 1 according to this embodiment, the inner diameter of the extension 6d to the through hole 6c is smoothly connected via the bend 6e without significant change. Therefore, the pressure loss of the exhaust gas can be suppressed. As a result, the exhaust gas can be smoothly introduced into the intake passage 6.

[0087] As described above, according to this disclosure, an internal combustion engine 1 is capable of providing condensate that can easily return to the exhaust circulation passage 12 and easily introduce exhaust circulation gas.

[0088] <Other Implementation Methods>

[0089] The embodiments of this disclosure have been described above, but this disclosure is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the invention. In particular, the various modifications described in this specification can be arbitrarily combined as needed.

[0090] (a) In the above embodiment, vehicle C is described as a front-wheel drive type with a transversely mounted internal combustion engine 1, but this disclosure is not limited thereto. The configuration of the internal combustion engine 1, transmission 21, and differential gearbox 22 can, for example, be a vehicle with a longitudinally mounted internal combustion engine 1 in which the crankshaft 2b is positioned in the longitudinal direction Q of vehicle C. Furthermore, vehicle C can be a four-wheel drive vehicle with a transmission for transmitting power to the rear wheels housed in the differential gearbox 22. Additionally, the differential gearbox 22 can also be part of the housing of a transmission drive axle that integrally forms the transmission 21 and the differential gear.

[0091] (b) In the above embodiment, the exhaust purification device 10 was described using a catalyst section 10a coated with a three-way catalyst as an example, but this disclosure is not limited thereto. The exhaust purification device 10 may also be a device such as a gasoline engine particulate filter or a diesel engine particulate filter that adsorbs soot.

[0092] (c) In the above embodiment, an example of dividing the exhaust recirculation passage 12 into multiple passages was used for illustration, but this disclosure is not limited thereto. The exhaust recirculation passage 12 may be configured to connect the outlet pipe 10c of the exhaust purification device 10 to the intake passage 6. In addition, the material used for each passage of the exhaust recirculation passage 12 is not limited thereto and may be varied appropriately.

[0093] (d) In the above embodiment, an example was described using an inlet side 16a disposed between the cylinder block 2 and the catalyst section 10a of the exhaust purification device 10, and an outlet side 16b disposed in the space S, but this disclosure is not limited thereto. At least, the inlet side 16a (one side) of the cooling device 16 may be disposed between the cylinder block 2 and the catalyst section 10a of the exhaust purification device 10, and the remaining part of the cooling device 16 (the other side) may be disposed in the space S.

[0094] This application is based on Japanese Patent Application No. 2020-168220, filed on October 5, 2020, the contents of which are incorporated herein by reference.

Claims

1. An internal combustion engine, comprising: The cylinder block forms the cylinder and holds the crankshaft in place; The intake passage supplies intake air to the cylinder; A turbocharger that pressurizes the intake air flowing through the intake passage; An exhaust purification device is disposed offset relative to the turbocharger in the extension direction of the crankshaft and extends in the extension direction of the cylinder. An exhaust recirculation passage is connected from the downstream of the exhaust purification device to the intake passage; An exhaust recirculation valve is disposed offset relative to the exhaust purification device in the extension direction of the crankshaft on the exhaust recirculation passage. as well as A cooling device is configured on the exhaust circulation channel to cool the exhaust gas flowing through the exhaust circulation channel using coolant. Along the extending direction of the crankshaft, the exhaust recirculation valve, the cooling device, and the exhaust purification device are arranged sequentially. One side of the inlet side of the cooling device is disposed between the exhaust purification device and the cylinder block, the lower part of the turbocharger is located between the exhaust recirculation valve and the exhaust purification device, and the other side of the outlet side of the cooling device is disposed in the space surrounded by the turbocharger, the exhaust purification device and the exhaust recirculation valve.

2. The internal combustion engine according to claim 1, The internal combustion engine is installed on the vehicle. The vehicle's power transmission device is located below the cooling device.

3. The internal combustion engine according to claim 1, The cooling device is configured at an angle so that it approaches the cylinder block as it approaches the exhaust purification device.

4. The internal combustion engine according to claim 2, The cooling device is configured at an angle so that it approaches the cylinder block as it approaches the exhaust purification device.

5. The internal combustion engine according to claim 1, It also has a coolant supply channel for supplying coolant to the cooling device. The coolant supply channel passes between the exhaust purification device and the cooling device.

6. The internal combustion engine according to claim 2, It also has a coolant supply channel for supplying coolant to the cooling device. The coolant supply channel passes between the exhaust purification device and the cooling device.

7. The internal combustion engine according to claim 3, It also has a coolant supply channel for supplying coolant to the cooling device. The coolant supply channel passes between the exhaust purification device and the cooling device.

8. The internal combustion engine according to claim 4, It also has a coolant supply channel for supplying coolant to the cooling device. The coolant supply channel passes between the exhaust purification device and the cooling device.

9. The internal combustion engine according to any one of claims 1 to 8, The exhaust recirculation passage is arranged at an angle downwards as it approaches the exhaust purification device from the intake passage.

10. The internal combustion engine according to any one of claims 1 to 8, The internal combustion engine is installed on the vehicle. The vehicle has a heater device for heating the vehicle's interior. After passing through the cooling device, the coolant flows to the heater device.

11. The internal combustion engine according to claim 9, The internal combustion engine is installed on the vehicle. The vehicle has a heater device for heating the vehicle's interior. After passing through the cooling device, the coolant flows to the heater device.

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