Cylinder head and engine

Abstract

The cylinder head (4) comprises: a plurality of exhaust ports (41) for exhausting exhaust gas from a combustion chamber; a plurality of intake ports (42) for introducing fresh air into the combustion chamber; an intake collection section (43) for collecting the plurality of intake ports (42); and a second EGR pipe (21b) for passing EGR gas, wherein the exhaust outlets (41b) of the plurality of exhaust ports (41) and the EGR gas inlet (44a) of the second EGR pipe (21b) are arranged side by side on a flat left side surface (4a), and the fresh air inlet (43a) of the intake collection section (43) and the EGR gas outlet (44b) of the second EGR pipe (21b) are arranged side by side on a flat right side surface (4b).

Description

Technical Field

[0001] The present invention relates to a cylinder head and an engine having the cylinder head. Background Art

[0002] Patent Document 1 below discloses an engine having an EGR passage built inside a cylinder head. Patent Document 2 below discloses an engine having an intake manifold and a cylinder head integrally formed. Patent Document 3 below discloses an engine having a thermostat built inside a cylinder head.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2015-34530

[0004] Patent Document 2: Japanese Patent Application Publication No. 2017-180227

[0005] Patent Document 3: Japanese Patent No. 3850940

[0006] In Patent Documents 1 to 3, engine components such as the EGR passage, intake manifold, and thermostat are formed integrally with the cylinder head, but the cylinder head has a stepped shape on the surface, which makes six-sided processing difficult. Therefore, processing time is increased, resulting in high costs. Summary of the invention

[0007] Therefore, in view of the above-mentioned problems, an object of the present invention is to provide a cylinder head having a shape that allows easy six-side processing and an engine including the cylinder head.

[0008] The cylinder head of the present invention comprises: a plurality of exhaust ports for extracting exhaust gas from a combustion chamber; a plurality of intake ports for introducing fresh air into the above-mentioned combustion chamber; an intake collection section for collecting the plurality of intake ports; and an EGR flow path for passing EGR gas, wherein the exhaust outlets of the above-mentioned plurality of exhaust ports and the EGR gas inlet of the above-mentioned EGR flow path are arranged side by side on a flat first side surface, and the fresh air inlet of the above-mentioned intake collection section and the EGR gas outlet of the above-mentioned EGR flow path are arranged side by side on a flat second side surface opposite to the above-mentioned first side surface.

[0009] In the cylinder head of the present invention, the exhaust outlets of multiple exhaust ports and the EGR gas inlet of the EGR flow path are arranged side by side on the flat first side, and the new air inlet of the intake collection section and the EGR gas outlet of the EGR flow path are arranged side by side on the flat second side, so six-sided processing is easy.

[0010] In the cylinder head of the present invention, it is also possible to further include: a thermostat housing, whose upper portion is opened and connected to the cooling water outlet pipe; a water jacket, which uses cooling water to cool the above-mentioned combustion chamber; and a cooling water passage, which is connected to the above-mentioned thermostat housing and the above-mentioned water jacket, the above-mentioned water jacket is formed to allow cooling water to flow from the exhaust side to the intake side, and the above-mentioned cooling water passage is formed to allow cooling water to flow from the exhaust side to the above-mentioned thermostat housing side, the height of the above-mentioned water jacket on the above-mentioned exhaust side is formed to be higher than the height of the above-mentioned water jacket on the above-mentioned intake side, and the height of the above-mentioned cooling water passage on the above-mentioned thermostat housing side is formed to be higher than the height of the above-mentioned cooling water passage on the above-mentioned exhaust side.

[0011] Since the height of the water jacket on the exhaust side is formed to be higher than that on the intake side, air is likely to accumulate on the exhaust side. However, by forming the height of the cooling water passage on the thermostat housing side to be higher than the height of the above-mentioned cooling water passage on the exhaust side, the air accumulated in the water jacket on the exhaust side can be sent to the thermostat housing side via the cooling water passage, thereby improving the cooling efficiency of the engine.

[0012] In the cylinder head of the present invention, the cooling water outlet of the thermostat housing may be opened in a processed surface of the upper surface processed to be flat.

[0013] According to this configuration, since the cooling water outlet of the thermostat case is disposed on the processed surface of the upper surface processed to be flat, six-side processing is easy.

[0014] The engine of the present invention may include the above-mentioned cylinder head, and a cooling water pump may be arranged directly below the above-mentioned thermostat housing.

[0015] According to this structure, the engine can be designed compactly. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a perspective view of the engine according to the present embodiment.

[0017] Figure 2 It is a perspective view of the engine according to the present embodiment.

[0018] Figure 3A It is an exploded perspective view of the cylinder head, intake manifold and exhaust manifold.

[0019] Figure 3B It is an exploded perspective view of the cylinder head, intake manifold and exhaust manifold.

[0020] Figure 4 It is a cross-sectional perspective view of the cylinder head.

[0021] Figure 5A It is a cross-sectional view of the lower part of the cylinder head in the vertical direction.

[0022] Figure 5B It is a cross-sectional view of the center portion in the vertical direction of the cylinder head.

[0023] Figure 5C It is a cross-sectional view of the upper part of the cylinder head in the vertical direction.

[0024] Figure 6 It is a cross-sectional view of the cylinder block and cylinder head. DETAILED DESCRIPTION

[0025] Below, while referring to the attached Figure 1 Embodiments of the present invention will be described.

[0026] First, refer to Figure 1 and Figure 2 , while explaining the schematic structure of the engine 1. In the following description, the two sides parallel to the crankshaft 2 are referred to as left and right, the side where the cooling fan 8 is arranged is referred to as the front side, the side where the flywheel housing 9 is arranged is referred to as the rear side, the side where the exhaust manifold 6 is arranged is referred to as the left side, the side where the intake manifold 5 is arranged is referred to as the right side, the side where the cylinder head cover 7 is arranged is referred to as the upper side, and the side where the oil pan 11 is arranged is referred to as the lower side. For the convenience of description, these are used as the basis for the positional relationship of the four directions and the upper and lower parts of the engine 1.

[0027] An engine 1 as a prime mover mounted on a working machine such as an agricultural machine, a construction machine or an engineering machine has a cylinder block 3, which has a crankshaft 2 and a piston (not shown) built in as an engine output shaft. A cylinder head 4 is mounted on the cylinder block 3. An intake manifold 5 is arranged on the right side of the cylinder head 4, and an exhaust manifold 6 is arranged on the left side of the cylinder head 4. The upper surface 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 provided on the front surface side of the engine 1. Rotational power is transmitted to the cooling fan 8 from the front end side of the crankshaft 2 via a V-belt for the cooling fan.

[0028] A flywheel housing 9 is provided on the rear surface side of the engine 1. A flywheel 10 is accommodated in the flywheel housing 9 in a state of being supported on the rear end side of the crankshaft 2. The rotational power of the engine 1 is transmitted from the crankshaft 2 to the working part of the working machine via the flywheel 10. An oil pan 11 for storing engine oil is arranged on the lower surface of the cylinder block 3. The engine oil in the oil pan 11 is supplied to each lubricating part of the engine 1 via the oil pump in the cylinder block 3, and then returns to the oil pan 11.

[0029] A fuel supply pump 13 is provided below the intake manifold 5 on the right side of the cylinder block 3. In addition, the engine 1 is provided with four-cylinder injectors 14, each of which has an electromagnetic opening and closing control type fuel injection valve. By opening and closing the fuel injection valve of each injector 14, the high-pressure fuel in the common rail is injected from each injector 14 to each cylinder of the engine 1.

[0030] A cooling water pump 15 for supplying cooling water is arranged on the front surface side of the cylinder block 3. The cooling water pump 15 is driven together with the cooling fan 8 via the V-belt for the cooling fan by the rotational power of the crankshaft 2. The cooling water in the radiator (not shown) mounted on the working machine is supplied to the cylinder block 3 and the cylinder head 4 by the driving of the cooling water pump 15, and the engine 1 is cooled. The cooling water that contributes to the cooling of the engine 1 returns to the radiator. In addition, an AC generator 16 is arranged above the cooling water pump 15.

[0031] The cooling water pump 15 is arranged below the intake manifold 5, and the cooling water inlet pipe 30 connected to the cooling water outlet of the radiator is arranged on the right side surface of the cylinder block 3 at the same height as the cooling water pump 15. In addition, the cooling water outlet pipe 31 connected to the cooling water inlet of the radiator is fixed to the upper right surface of the cylinder head 4.

[0032] The intake throttle member 17 is connected to the intake manifold 5. Fresh air (outside air) sucked into an air cleaner (not shown) is dust-removed and purified in the air cleaner, and then sent to the intake manifold 5 through the intake throttle member 17 and supplied to each cylinder of the engine 1.

[0033] An EGR device 18 is disposed at the upper portion of the intake manifold 5. The EGR device 18 is a device for supplying a portion of the exhaust gas of the engine 1 (EGR gas from the exhaust manifold 6) to the intake manifold 5, and 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 and the EGR pipe 21.

[0034] The downward opening end of the EGR valve box 19 is bolted to the inlet portion protruding upward from the intake manifold 5. In addition, the rightward opening end of the EGR valve box 19 is connected to the outlet side of the EGR piping 21. The amount of EGR gas supplied from the EGR piping 21 to the intake manifold 5 is adjusted by adjusting the opening of the EGR valve member (not shown) accommodated in the EGR valve box 19. The EGR valve member is driven by an actuator 22 installed in the EGR valve box 19.

[0035] Fresh air supplied to the intake manifold 5 from the air filter via the intake throttle member 17 and EGR gas (a part of the exhaust gas discharged from the exhaust manifold 6) supplied to the intake manifold 5 from the exhaust manifold 6 via the EGR valve box 19 are mixed in the intake manifold 5. In this way, by causing a part of the exhaust gas discharged from the exhaust manifold 6 to flow back to the engine 1 via the intake manifold 5, the combustion temperature is lowered, and the emission of nitrogen oxides (NOX) from the engine 1 is reduced.

[0036] The EGR pipe 21 is connected to the EGR cooler 20 and the EGR valve box 19. The EGR pipe 21 includes a first EGR pipe 21a disposed on the right side of the cylinder head 4, a second EGR pipe 21b formed at the rear end of the cylinder head 4, and a third EGR pipe 21c disposed on the left side of the cylinder head 4.

[0037] The first EGR pipe 21 a is an L-shaped pipe as a whole. The inlet side of the first EGR pipe 21 a is connected to the outlet side of the second EGR pipe 21 b , and the outlet side is connected to the EGR valve box 19 .

[0038] like Figure 2 As shown, the second EGR pipe 21b is formed at the rear end of the cylinder head 4 in a manner penetrating 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.

[0039] 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 is saved and external impact is not easily received.

[0040] Next, refer to Figure 3A , Figure 3B , Figure 4 , Figure 5A , Figure 5B as well as Figure 5C The structure of the cylinder head 4 will be described. Figure 3A and Figure 3B is an exploded perspective view of a cylinder head 4, an intake manifold 5, and an exhaust manifold 6. Figure 3A and Figure 3B These are three-dimensional images observed from different directions. Figure 4 It is a cross-sectional perspective view of the vicinity of the center portion in the vertical direction of the cylinder head 4 . Figure 5A , Figure 5B as well as Figure 5C These are cross-sectional views of a lower portion, a central portion, and an upper portion of the cylinder head 4 in the up-down direction, respectively.

[0041] The cylinder head 4 is rectangular in shape as a whole. After casting, six surfaces (four sides and two upper and lower surfaces) of the cylinder head 4 are cut. Figure 4 As shown in the figures, the cylinder head 4 comprises: a plurality of exhaust ports 41 for extracting exhaust gas from the combustion chamber, a plurality of intake ports 42 for introducing fresh air into the combustion chamber, an intake converging portion 43 for converging the plurality of intake ports 42, and a second EGR pipe 21b (equivalent to the EGR flow path of the present invention) for passing the EGR gas.

[0042] The exhaust port 41 is connected to an exhaust valve hole 41a (see Figure 3B and Figure 5A The exhaust manifold 6 is connected to the left side 4a of the cylinder head 4, and the exhaust gas is discharged from the combustion chamber. An exhaust valve (not shown) is provided at the position of the exhaust valve hole 41a. The exhaust port 41 extends to the left from the exhaust valve hole 41a, and the exhaust outlet 41b opens on the left side 4a (corresponding to the first side of the present invention) of the cylinder head 4. The plurality of exhaust outlets 41b are arranged side by side in the front-to-back direction. On the other hand, the exhaust manifold 6 has a plurality of exhaust inlets 6a connected to the plurality of exhaust outlets 41b arranged side by side in the front-to-back direction on the right side connected to the left side 4a of the cylinder head 4.

[0043] The intake port 42 is connected to an intake valve hole 42a (see Figure 3B and Figure 5A The intake port 42 extends from the intake valve hole 42a to the right.

[0044] An intake collection section 43 is formed on the right side 4b of the cylinder head 4, where the plurality of intake ports 42 are collected. The intake collection section 43 is connected to the fresh air inlets of the plurality of intake ports 42. The fresh air inlet 43a of the intake collection section 43 opens on the right side 4b (corresponding to the second side face of the present invention) of the cylinder head 4. On the other hand, the intake manifold 5 is provided with a fresh air outlet 5a connected to the fresh air inlet 43a on the left side connected to the right side 4b of the cylinder head 4.

[0045] As described above, the second EGR pipe 21b is formed to penetrate the rear end of the cylinder head 4 in the left-right direction. The second EGR pipe 21b is arranged behind the exhaust port 41 and the intake port 42. The EGR gas inlet 44a of the second EGR pipe 21b opens behind the left side 4a of the cylinder head 4. On the other hand, the exhaust manifold 6 is provided with an EGR gas outlet 6b of the third EGR pipe 21c connected to the EGR gas inlet 44a on the right side connected to the left side 4a of the cylinder head 4. A plurality of exhaust outlets 41b and the EGR gas inlet 44a are arranged side by side in the front-to-back direction on the left side 4a of the flat cylinder head 4 after cutting. That is, a plurality of exhaust outlets 41b and the EGR gas inlet 44a open on the same surface.

[0046] In addition, the EGR gas outlet 44b of the second EGR pipe 21b opens at the rear of the right side surface 4b of the cylinder head 4. The fresh air inlet 43a and the EGR gas outlet 44b of the intake air collection portion 43 are arranged side by side on the right side surface 4b of the cylinder head 4 that is flat after cutting. That is, the fresh air inlet 43a and the EGR gas outlet 44b open on the same surface.

[0047] A thermostat housing 45 having an upper opening and communicating with the cooling water outlet pipe 31 is provided in front of the right side surface 4b of the cylinder head 4. The thermostat housing 45 is provided in front of the intake air collecting portion 43. A thermostat (not shown) is arranged inside the thermostat housing 45. The cooling water outlet 45a of the thermostat housing 45 opens on the processed surface of the upper surface 4c of the cylinder head 4 processed to be flat.

[0048] A water jacket 46 is provided inside the cylinder head 4. The water jacket 46 is formed around the exhaust port 41 and the intake port 42. Figure 5A and Figure 5B As shown in FIG. 1 , the water jacket 46 is provided on both the exhaust side and the intake side in a portion extending from the lower surface side of the cylinder head 4 in the vertical direction to the vicinity of the center portion. Figure 5C As shown in FIG. 1 , the water jacket 46 is provided only on the exhaust side on the upper surface side of the cylinder head 4. That is, the height of the water jacket 46 on the exhaust side is formed to be higher than the height of the water jacket 46 on the intake side. Figure 5A and Figure 5B As indicated by the middle arrow W, the cooling water in the water jacket 46 flows in a direction from the exhaust side toward the intake side.

[0049] In addition, a cooling water passage 47 communicating with the thermostat housing 45 and the water jacket 46 is provided inside the cylinder head 4. The cooling water passage 47 is formed at the front portion of the cylinder head 4. The height of the cooling water passage 47 on the thermostat housing 45 side is formed to be higher than the height of the cooling water passage 47 on the exhaust side. Figure 5C As shown in FIG. 1 , the height of the cooling water passage 47 on the thermostat housing 45 side is substantially the same as the height of the cooling water passage 47 on the exhaust side. Thus, the cooling water in the cooling water passage 47 flows in the direction from the exhaust side toward the thermostat housing 45 side. As a result, the air accumulated on the exhaust side of the water jacket 46 can be sent to the thermostat housing 45 side, and the cooling efficiency of the engine 1 can be improved.

[0050] Figure 61 is a cross-sectional view of the cylinder block 3 and the cylinder head 4 cut in the vertical direction at the position of the thermostat housing 45. The cooling water pump 15 is arranged directly below the thermostat housing 45. More specifically, the thermostat housing 45 and the cooling water inlet 15a of the cooling water pump 15 are arranged side by side in the upward direction. A bottom bypass passage 32 for cooling water to flow when the thermostat is closed is connected to the lower part of the thermostat housing 45. The bottom bypass passage 32 is formed in the front part of the cylinder block 3. The bottom bypass passage 32 extends in the vertical direction and is connected to the cooling water inlet 15a of the cooling water pump 15. By arranging the cooling water pump 15 directly below the thermostat housing 45, the bottom bypass passage 32 can be formed into a simple shape, so the engine 1 can be designed compactly.

[0051] The embodiments of the present invention are described above based on 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 indicated by the description of the above-mentioned embodiments, but also indicated by the scope of the claims, and also includes all changes within the meaning and scope equivalent to the scope of the claims.

[0052] Description of Reference Numerals

[0053] 1…engine; 4…cylinder head; 4a…left side; 4b…right side; 4c…upper surface; 15…cooling water pump; 21b…second EGR pipe; 41…exhaust port; 41b…exhaust outlet; 42…intake port; 43…intake air collection section; 43a…fresh air inlet; 44a…EGR gas inlet; 44b…EGR gas outlet; 45…thermostat housing; 45a…cooling water outlet; 46…water jacket; 47…cooling water passage.

Claims

1. A cylinder head of an engine, wherein: have: a plurality of exhaust ports for directing exhaust gases from the combustion chamber; a plurality of air inlets for introducing fresh air into the combustion chamber; An air intake collecting portion for collecting the plurality of air intake ports; and An EGR flow path through which the EGR gas passes, The exhaust gas outlets of the plurality of exhaust ports and the EGR gas inlet of the EGR flow path are arranged side by side on the flat first side surface, The fresh air inlet of the intake converging portion and the EGR gas outlet of the EGR flow path are arranged side by side on a flat second side surface opposite to the first side surface. The EGR flow path is connected to an exhaust manifold attached to the first side surface via an EGR cooler.

2. The cylinder head according to claim 1, wherein: Also available: A thermostat housing, the upper portion of which is open and communicated with a cooling water outlet pipe; a water jacket that cools the combustion chamber using cooling water; and a cooling water passage communicating with the thermostat housing and the water jacket, The water jacket is formed so that cooling water flows from the exhaust side toward the intake side. The cooling water passage is formed so that the cooling water flows from the exhaust side toward the thermostat housing side. The height of the water jacket on the exhaust side is formed to be higher than the height of the water jacket on the intake side. The height of the cooling water passage on the thermostat case side is formed to be greater than the height of the cooling water passage on the exhaust side.

3. The cylinder head according to claim 2, wherein: The cooling water outlet of the thermostat housing opens on the processed surface of the upper surface processed to be flat.

4. An engine, wherein: The engine comprises the cylinder head according to claim 2 or 3, A cooling water pump is arranged directly below the thermostat housing.

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