engine

Abstract

The engine (1) of the present application is provided with an exhaust manifold (6), an intake manifold (5), and an EGR device (18) that supplies EGR gas from the exhaust manifold (6) to the intake manifold (5), the upper end of an EGR cooler (20) that extends downward being attached to a downwardly projecting attachment portion (62) provided to the exhaust manifold (6).

Description

[0001] This application is a divisional application of application number 201880080592.9, which entered the national phase on June 12, 2020, and is entitled "Engine". Technical Field

[0002] This invention relates to engines equipped with an EGR device. Background Technology

[0003] Engines equipped with an EGR system that recirculates a portion of the exhaust gas back into the intake air are known to exist. The EGR system lowers the combustion temperature by recirculating the low-oxygen-concentration exhaust gas (EGR gas) back into the intake air, thereby suppressing the formation of nitrogen oxides. Generally, the EGR gas is cooled by an EGR cooler before being recirculated into the intake air.

[0004] Patent Document 1 discloses a structure in which an EGR cooler is provided on the side of the cylinder block, the flange on the EGR gas inlet side of the EGR cooler is supported by an exhaust manifold, and the flange on the EGR gas outlet side of the EGR cooler is supported by an exhaust connecting pipe, which is a component different from the exhaust manifold. Patent Document 2 discloses a structure in which the EGR cooler is fixed to the outer side of the exhaust manifold using two straps.

[0005] Patent Document 1: Japanese Patent No. 6067092

[0006] Patent Document 2: Japanese Patent No. 3633824

[0007] In Patent Document 1, because the components supporting the EGR gas inlet and outlet sides are different, stress is applied to the flange of the EGR cooler due to the difference in thermal expansion of each component. Furthermore, in Patent Document 2, multiple belts are required to support the EGR cooler, raising concerns about increased costs due to the increased number of components. Summary of the Invention

[0008] Therefore, the present invention was made in view of the above-mentioned problems, and its object is to provide an engine that can suppress the stress applied to the flange of the EGR cooler due to thermal expansion and reduce the number of components.

[0009] The engine of the present invention includes an exhaust manifold, an intake manifold, and an EGR device for supplying EGR gas from the exhaust manifold to the intake manifold.

[0010] The upper end of the EGR cooler, which extends downwards, is installed in the downward-protruding mounting portion of the exhaust manifold.

[0011] In this invention, a portion of the EGR piping extending from the EGR cooler to the intake manifold may also be formed inside the exhaust manifold.

[0012] In this invention, the EGR cooler may also be configured to include a cooling section for cooling EGR gas and a switching valve for controlling the inflow of EGR gas into the cooling section.

[0013] When the temperature of the EGR gas from the exhaust manifold is below a specified temperature, the switching valve prevents the EGR gas from flowing into the cooling section; when the temperature of the EGR gas from the exhaust manifold is higher than the specified temperature, the switching valve allows the EGR gas to flow into the cooling section.

[0014] In this invention, the mounting portion may also be configured to include: a first opening for supplying EGR gas from the exhaust manifold to the EGR cooler; and a second opening for supplying EGR gas from the EGR cooler to the EGR piping.

[0015] In this invention, the EGR cooler may also be configured such that a supply port for supplying EGR gas and an outlet for discharging EGR gas are formed at the upper end of the EGR cooler, and the EGR cooler has a U-shaped path inside that connects to the supply port and the outlet.

[0016] According to the present invention, since the EGR cooler is supported by the exhaust manifold at only one point, the stress applied to the flange of the EGR cooler due to thermal expansion can be suppressed. Furthermore, since it is not necessary to use multiple belts or the like to support the EGR cooler, the number of components can be reduced. Attached Figure Description

[0017] Figure 1 This is a perspective view of the engine involved in this embodiment.

[0018] Figure 2 This is a perspective view of the engine involved in this embodiment.

[0019] Figure 3 This is an exploded 3D view of the exhaust manifold and EGR cooler.

[0020] Figure 4 These are the top view, front view, and rear view of the exhaust manifold.

[0021] Figure 5 This is a schematic cross-sectional view of an EGR cooler. Detailed Implementation

[0022] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0023] First, refer to Figure 1 and Figure 2 The general structure of engine 1 will be described. In the following description, the two sides parallel to crankshaft 2 will be referred to as left and right, the side where cooling fan 8 is located will be referred to as front, the side where flywheel housing 9 is located will be referred to as rear, the side where exhaust manifold 6 is located will be referred to as left, the side where intake manifold 5 is located will be referred to as right, the side where cylinder head cover 7 is located will be referred to as upper, and the side where oil pan 11 is located will be referred to as lower. For convenience, these will be used as the basis for the four-way and vertical positional relationship of engine 1.

[0024] An engine 1, used as a prime mover in agricultural machinery, construction machinery, civil engineering machinery, and similar equipment, comprises a cylinder block 3 containing a crankshaft 2 (serving as the engine output shaft) and pistons (not shown). A cylinder head 4 is mounted on the cylinder block 3. An intake manifold 5 is located on the right side of the cylinder head 4, and an exhaust manifold 6 is located on the left side. The upper side of the cylinder head 4 is covered by a cylinder head cover 7. The front and rear ends of the crankshaft 2 protrude from the front and rear sides of the cylinder block 3. A cooling fan 8 is located at the front of the engine 1. Rotational power is transmitted from the front end of the crankshaft 2 to the cooling fan 8 via a V-belt.

[0025] A flywheel housing 9 is provided at the rear of the engine 1. The flywheel 10 is housed within the flywheel housing 9, supported at the rear end of the crankshaft 2. The rotational power of the engine 1 is transmitted from the crankshaft 2 to the working part of the machine via the flywheel 10. An oil pan 11 for storing engine oil is provided on the lower surface of the cylinder block 3. The engine oil in the oil pan 11 is supplied to the various lubrication parts of the engine 1 by an oil pump (not shown) within the cylinder block 3, and then returns to the oil pan 11.

[0026] A fuel supply pump 13 is located below the intake manifold 5 on the right side of the cylinder block 3. Additionally, the engine 1 has four injectors 14, each equipped with an electromagnetically controlled fuel injection valve. By controlling the opening and closing of the fuel injection valves of each injector 14, high-pressure fuel from the common rail is injected from each injector 14 into each cylinder of the engine 1.

[0027] A cooling water pump 15 for supplying cooling water is disposed on the front side of the cylinder block 3. The cooling water pump 15 is driven by the rotational power of the crankshaft 2 via a V-belt of the cooling fan, together with the cooling fan 8. Cooling water in the radiator (not shown) of the machine is supplied to the cylinder block 3 and cylinder head 4 by the cooling water pump 15 to cool the engine 1. The cooling water that helps cool the engine 1 returns to the radiator. In addition, an alternator 16 is disposed above the cooling water pump 15.

[0028] An intake throttle valve assembly 17 is connected to the intake manifold 5. Fresh air (outside air) drawn in by the air filter (not shown) is cleaned and purified by the air filter, and then delivered to the intake manifold 5 via the intake throttle valve assembly 17 to supply each cylinder of the engine 1.

[0029] An EGR device 18 is disposed on the upper part of the intake manifold 5. The EGR device 18 is a device that supplies a portion of the exhaust gas of the engine 1 (EGR gas from the exhaust manifold 6) to the intake manifold 5. It includes an EGR pipe 21 connected to the exhaust manifold 6 via an EGR cooler 20, and an EGR valve box 19 that connects the intake manifold 5 to the EGR pipe 21.

[0030] The downward-facing open end of the EGR valve box 19 is secured to the upward-protruding inlet portion of the intake manifold 5 using bolts. Additionally, the right-facing open end of the EGR valve box 19 is connected to the outlet side of the EGR piping 21. The supply of EGR gas from the EGR piping 21 to the intake manifold 5 is adjusted by regulating the opening degree of the EGR valve component (not shown) housed within the EGR valve box 19. The EGR valve component is driven by an actuator 22 mounted on the EGR valve box 19.

[0031] Fresh air supplied from the air filter to the intake manifold 5 via the intake throttle assembly 17 mixes with EGR gas (a portion of the exhaust gas exiting the exhaust manifold 6) supplied from the exhaust manifold 6 via the EGR valve box 19 within the intake manifold 5. This causes a portion of the exhaust gas exiting the exhaust manifold 6 to flow back to the engine 1 via the intake manifold 5, thereby reducing combustion temperature and decreasing nitrogen oxides (NOx) emissions from the engine 1. X ) discharge volume.

[0032] EGR pipe 21 is connected to EGR cooler 20 and EGR valve box 19. EGR pipe 21 includes a first EGR pipe 21a disposed on the right side of cylinder head 4, a second EGR pipe 21b formed at the rear end of cylinder head 4, and a third EGR pipe 21c disposed on the left side of cylinder head 4.

[0033] The first EGR pipe 21a is an L-shaped pipe. The inlet side of the first EGR pipe 21a is connected to the outlet side of the second EGR pipe 21b, and the outlet side is connected to the EGR valve box 19.

[0034] like Figure 2 The second EGR pipe 21b is formed at the rear end of the cylinder head 4 in a manner that extends through the cylinder head 4 in the left-right direction. That is, the second EGR pipe 21b is integrated with the cylinder head 4. The inlet side of the second EGR pipe 21b is connected to the outlet side of the third EGR pipe 21c, and the outlet side is connected to the inlet side of the first EGR pipe 21a.

[0035] The third EGR pipe 21c is formed inside the exhaust manifold 6. That is, the third EGR pipe 21c is integrated with the exhaust manifold 6. By integrating the third EGR pipe 21c and the second EGR pipe 21b with the exhaust manifold 6 and the cylinder head 4, space can be saved and it is less susceptible to external impacts.

[0036] Figure 3 This is an exploded perspective view of the exhaust manifold 6 and the EGR cooler 20. Figure 4 These are top, front, and bottom views of the exhaust manifold 6. The exhaust manifold 6 includes a collection section 61 that collects exhaust gases from the exhaust ports of each cylinder into one and discharges them into an exhaust pipe, a mounting section 62 that protrudes downward from the rear end of the collection section 61, and an EGR piping section 63 that extends rearward from the mounting section 62. The aforementioned third EGR piping 21c is formed as the EGR piping section 63.

[0037] The mounting portion 62 of the exhaust manifold 6 includes: a first opening 62a for supplying EGR gas from the exhaust manifold 6 to the EGR cooler 20; and a second opening 62b for supplying EGR gas from the EGR cooler 20 to the third EGR pipe 21c. The first opening 62a and the second opening 62b are arranged side by side in a front-rear direction. An EGR gas extraction path 62c is formed inside the mounting portion 62, which communicates with the collecting portion 61 and the first opening 62a.

[0038] The EGR cooler 20 is a generally quadrangular prism extending vertically. The EGR cooler 20 is mounted on a downwardly protruding mounting portion 62 provided on the exhaust manifold 6. The upper end of the EGR cooler 20 is bolted to the mounting portion 62. In this embodiment, it is cantilevered on the exhaust manifold 6 in a manner parallel to (longitudinally) the axial direction of the cylinder (not shown).

[0039] The upper end of the EGR cooler 20 has a supply port 20a for supplying EGR gas from the exhaust manifold 6 and an outlet 20b for discharging EGR gas to the third EGR pipe 21c. The supply port 20a and outlet 20b are arranged side-by-side in the front-rear direction. The supply port 20a is connected to the first opening 62a of the exhaust manifold 6, and the outlet 20b is connected to the second opening 62b of the exhaust manifold 6. Furthermore, a U-shaped path connecting the supply port 20a and outlet 20b is formed inside the EGR cooler 20. After entering from the supply port 20a downwards, the EGR gas makes a U-turn and enters upwards towards the outlet 20b. Thus, the EGR gas supplied to the EGR cooler 20 from the supply port 20a exits from the outlet 20b through the U-shaped path.

[0040] In addition, such as Figure 2As shown, when viewed from the rear, the EGR cooler 20 overlaps with the gear housing 23. The gear housing 23 is positioned opposite the flywheel housing 9, and together with the flywheel housing 9, covers the camshaft gear (not shown) from the front and rear. By covering the camshaft gear with the gear housing 23 and the flywheel housing 9, sound insulation is achieved, thus reducing gear noise. The EGR cooler 20 is protected from external impacts (especially from the rear) by overlapping with the gear housing 23.

[0041] Figure 5 This is a schematic cross-sectional view of the EGR cooler 20, (a) showing the state with the switching valve 201 closed, and (b) showing the state with the switching valve 201 open. The arrows in the figure indicate the flow of EGR gas.

[0042] The EGR cooler 20 includes a cooling section 20c for cooling EGR gas and a switching valve 201 for controlling the flow of EGR gas into the cooling section 20c. The cooling section 20c is located at the lower part of the EGR cooler 20 and is supplied with cooling water by a cooling water pump 15, which cools the EGR gas passing through the cooling section 20c.

[0043] When the temperature of the EGR gas from exhaust manifold 6 is below a specified temperature, such as Figure 5 As shown in (a), the switching valve 201 closes the flow path to the cooling section 20c, preventing the EGR gas from flowing into the cooling section 20c. Therefore, when the EGR gas is at a low temperature, it is not supplied to the cooling section 20c, thus enabling preheating. On the other hand, when the temperature of the EGR gas from the exhaust manifold 6 is higher than the specified temperature, such as... Figure 5 As shown in (b), the switching valve 201 opens the flow path to the cooling section 20c, allowing EGR gas to flow into the cooling section 20c. Therefore, when the EGR gas is at a high temperature, the temperature of the EGR gas can be appropriately controlled by supplying EGR gas to the cooling section 20c.

[0044] The embodiments of the present invention have been described above with reference to the accompanying drawings, but it should be understood that the specific structure is not limited to these embodiments. The scope of the present invention is not only shown by the description of the above embodiments, but also indicated by the scope of the claims, and includes all modifications within the scope of the claims.

[0045] Explanation of reference numerals in the attached figures

[0046] 1… Engine; 3… Cylinder block; 4… Cylinder head; 5… Intake manifold; 6… Exhaust manifold; 18… EGR device; 20… EGR cooler; 20c… ​​Cooling section; 21… EGR piping; 62… Mounting section; 201… Switching valve.

Claims

1. An engine, wherein, The exhaust manifold connects to the EGR cooler. The length of the EGR cooler is along the vertical direction of the engine.

2. The engine according to claim 1, wherein, An EGR gas supply port is provided at the end of the EGR cooler. The supply port is connected to the exhaust manifold.

3. The engine according to claim 2, wherein, The supply port is located in the EGR cooler at the upper end of the exhaust manifold side.

4. The engine according to claim 1, wherein, The EGR cooler is connected to the connection point located on the exhaust manifold. The connection portion has an opening for supplying EGR gas from the exhaust manifold to the EGR cooler.

5. The engine according to claim 1, wherein, When viewed from the rear, the EGR cooler overlaps with the shroud assembly located in front of the flywheel.

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