Water-cooled engine

Abstract

The present invention provides a water-cooled engine capable of suppressing thermal deformation of a cylinder head. A head water jacket (20) has an exhaust port wall water passage (29) between a first exhaust inlet port wall (3d) and a second exhaust inlet port wall (3e), a cylinder head (6) has a cooling water injection passage (27) provided on a bottom wall (6c) of the cylinder head (6), the cooling water injection passage (27) is biased toward an exhaust end (6a) side, has a passage inlet (27a) close to the exhaust end (6a) and a passage outlet (27b) toward the exhaust port wall water passage (29), and the exhaust port wall has a heat sink (28) extending from the first exhaust inlet port wall (3d) toward the exhaust end (6a), and a water passage inlet to the exhaust port wall water passage (29) is formed between the heat sink (28) and the second exhaust inlet port wall (3e).

Description

[0001] This application is a divisional application of an application with an application date of May 2, 2018, application number “201810413252.5”, and invention name “Water-cooled engine”. Technical Field

[0002] The present invention relates to a water-cooled engine, and more particularly to a water-cooled engine capable of suppressing thermal deformation of a cylinder head. Background Art

[0003] Conventionally, there is a water-cooled engine having a cylinder head with an intake port, an exhaust port, and a head water jacket through which engine cooling water passes around these ports (see, for example, Patent Document 1).

[0004] This water-cooled engine has the advantage that the cylinder head can be strongly cooled by engine cooling water.

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 8-261059 (see FIG. 1, Figure 4 , Figure 5 )

[0006] <Problem> There is a possibility that the thermal deformation of the cylinder head will increase.

[0007] In this water-cooled engine, when the output is increased, the exhaust temperature rises, and cooling on the exhaust side is insufficient, which may cause greater thermal deformation of the cylinder head. Summary of the invention

[0008] An object of the present invention is to provide a water-cooled engine capable of suppressing thermal deformation of a cylinder head.

[0009] The technical features of the present invention are as follows.

[0010] like Figure 1A As shown, the present invention provides a water-cooled engine, characterized in that it has a cylinder head 6, the cylinder head 6 has an intake port 2, an exhaust port 3, and a head water jacket 20 for allowing engine cooling water 36 to pass around the intake port 2 and the exhaust port 3,

[0011] The mounting direction of the crankshaft 8 is defined as the front-rear direction, the width direction of the cylinder head 6 orthogonal to the front-rear direction is defined as the lateral direction, one lateral end of the cylinder head 6 is defined as the exhaust end 6a, and the other lateral end is defined as the intake end 6b.

[0012] The exhaust port 3 has a first exhaust valve port 3a and a second exhaust valve port 3b closer to the exhaust end 6a than the first exhaust valve port 3a, and the exhaust port wall has a first exhaust inlet port wall 3d close to the first exhaust valve port 3a and a second exhaust inlet port wall 3e close to the second exhaust valve port 3b.

[0013] The cover water jacket 20 has an exhaust port wall water passage 29 between the first exhaust inlet port wall 3d and the second exhaust inlet port wall 3e.

[0014] The cylinder head 6 has a cooling water injection passage 27 disposed on the bottom wall 6c of the cylinder head 6. The cooling water injection passage 27 is biased toward the exhaust end 6a side and has a passage inlet 27a close to the exhaust end 6a and a passage outlet 27b toward the exhaust port inter-wall water passage 29.

[0015] The exhaust port wall has fins 28 extending from the first exhaust inlet port wall 3 d toward the exhaust end 6 a , and a portion between the fins 28 and the second exhaust inlet port wall 3 e forms a water channel inlet to the exhaust port inter-wall water channel 29 .

[0016] The present invention has the following effects.

[0017] <Effect> Thermal deformation of the cylinder head 6 can be suppressed.

[0018] like Figure 1A As shown, the bottom wall 6c of the cylinder head 6 near the exhaust end 6a where the heat load is high is strongly cooled by the engine cooling water 36 passing through the cooling water injection passage 27. In addition, the first exhaust inlet port wall 3d and the second exhaust inlet port wall 3e where the heat load is high are strongly cooled by the engine cooling water 36 injected from the cooling water injection passage 27. Therefore, insufficient cooling on the exhaust side is improved, thereby suppressing thermal deformation of the cylinder head 6.

[0019] <<Effect>> The cooling performance of the first exhaust inlet port wall 3d is high.

[0020] Due to the heat dissipation of the heat dissipation fins 28, the heat dissipation performance of the first exhaust gas inlet port wall 3d is high.

[0021] <<Effect>> The cooling performance of the first exhaust inlet port wall 3d and the second exhaust inlet port wall 3e is high.

[0022] like Figure 1A As shown, the engine cooling water 36 does not spread in a direction away from the exhaust port wall water channel 29 due to the heat sink 28, and can smoothly flow into the exhaust port wall water channel 29, thereby improving the cooling performance of the first exhaust inlet port wall 3d and the second exhaust inlet port wall 3e. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is a diagram for explaining a cylinder head of a water-cooled engine according to an embodiment of the present invention, Figure 1A is a schematic top view. Figure 1B It is along Figure 1A The cross-sectional view of line BB, Figure 1C It is along Figure 1ACross-sectional view of the CC line.

[0024] Figure 2 It is a longitudinal cross-sectional view of a combustion chamber of a water-cooled engine according to an embodiment of the present invention.

[0025] Figure 3 It is a longitudinal sectional front view of the engine according to the embodiment of the present invention.

[0026] Figure 4 yes Figure 3 A longitudinal sectional side view of an engine.

[0027] Figure 5 yes Figure 3 Front view of the engine.

[0028] Figure 6 yes Figure 3 Side view of the engine.

[0029] Figure 7 yes Figure 3 Top view of the engine.

[0030] Description of reference numerals:

[0031] 2: Intake port, 2a: Intake valve port, 2b: Intake outlet port wall, 2c: Intake valve shaft inserted through boss, 3: Exhaust port, 3a: First exhaust valve port, 3b: Second exhaust valve port, 3d: First exhaust inlet port wall, 3e: Second exhaust inlet port wall, 5: Cylinder block, 6: Cylinder head, 6a: Exhaust end, 6b: Intake end, 6c: Bottom wall, 6d: Top wall, 6e: Push rod chamber wall, 8: Crankshaft, 15: Fuel injector, 20: Cover water jacket, 27: Cooling water injection passage, 27a: Passageway inlet 27a: channel outlet, 28: heat sink, 29: exhaust port wall water channel, 29a: water channel inlet, 29b: water channel outlet, 30: intake and exhaust port wall water channel, 30a: water channel inlet, 30b: water channel outlet, 31: second cooling water injection channel, 31a: second channel inlet, 31b: second channel outlet, 32: second heat sink, 32a: throttle channel, 33: cover gasket, 33a: pressure strip, 34: combustion chamber top wall, 34a: periphery, 35: pressing wall, 36: engine cooling water DETAILED DESCRIPTION

[0032] FIG. 1 is a diagram for explaining a water-cooled engine according to an embodiment of the present invention. In this embodiment, a water-cooled common rail inline four-cylinder diesel engine is described.

[0033] The outline of the engine is as follows.

[0034] like Figure 3As shown, the engine comprises: a cylinder block 5; a cylinder head 6, assembled on the upper part of the cylinder block 5; a cylinder head cover 7, assembled on the upper part of the cylinder head 6; an oil pan 4, assembled on the lower part of the cylinder block 5; a belt transmission mechanism 9, as shown Figure 4 As shown, the crankshaft 8 is arranged in the front-to-rear direction at the front of the cylinder block 5; the flywheel housing 10 is arranged at the rear of the cylinder block 5; the intake manifold 11 is arranged at the rear of the cylinder block 5; Figure 3 As shown, the exhaust manifold 12 is provided on one lateral side of the cylinder head 6 with the width direction of the engine perpendicular to the front-rear direction as the lateral direction; and the exhaust manifold 12 is provided on the other lateral side of the cylinder head 6.

[0035] The engine has a fuel injection device, a vibration-proof device, a water cooling device, a lubrication device, and an oil cooling device.

[0036] The fuel injection device is of common rail type and has Figure 6 The fuel supply pump 13 and the common rail 14 shown in FIG. Figure 4 The fuel injector 15 is shown to inject fuel into the combustion chamber.

[0037] like Figure 3 As shown, the anti-vibration device has a rotary balancer 1, thereby offsetting the secondary vibration of the engine, thereby reducing the vibration of the engine.

[0038] The water cooling device comprises: a radiator (not shown); a water inlet chamber 16, such as Figure 3 As shown, it is arranged on the intake side of the cylinder block 5; the water pump 17, as Figure 6 As shown, it is arranged in front of the water inlet chamber 16; the water relay chamber 18, as shown Figure 3 As shown, a water jacket 19 is provided in the lower part of the water inlet chamber 16 behind the water pump 17; a cylinder water jacket 19 is provided in the cylinder block 5; and a head water jacket 20 is provided in the cylinder head 6.

[0039] The water cooling device uses the pump pressure of the water pump 17 to circulate the engine cooling water dissipated by the radiator in the order of the water inlet chamber 16, the water pump 17, the water relay chamber 18, the cylinder water jacket 19, the head water jacket 20, and the radiator to water-cool the engine.

[0040] The lubrication device comprises: an oil pump (not shown), which is built into the rear part of the cylinder block 5; an oil cooler 21, such as Figure 3 As shown, it is contained in the water relay chamber 18; the oil filter 23 is arranged on the auxiliary equipment mounting base 22 together with the oil cooler 21; the oil passage 24 is arranged in the thick wall of the intake side of the cylinder block 5, and the lubrication device uses the pump pressure of the oil pump to make the engine oil 4a in the oil pan 4 press the oil pump, oil cooler 21, oil filter 23, oil passage 24, Figure 3 The engine sliding parts such as the bearing 8a of the crankshaft 8 and the oil pan 4 circulate in this order to forcibly lubricate the engine sliding parts.

[0041] like Figure 3 As shown, the oil cooling device comprises: an oil injection delivery passage 25, which is arranged in parallel with the oil passage 24 in the thick wall on the intake side of the cylinder block 5; an oil nozzle 25a, which is arranged below the piston 26; and a cooling channel 26a, which is arranged inside the piston 26. The oil cooling device causes a portion of the engine oil 4a that passes through the oil cooler 21 and the oil filter 23 of the lubrication device in sequence to be diverted to the oil injection delivery passage 25 in the auxiliary equipment mounting base 22 and injected from the oil nozzle 25a into the cooling channel 26a to oil-cool the piston 26.

[0042] The structure of the water cooling device is as follows.

[0043] like Figure 1A As shown, there is a cylinder head 6 having an intake port 2 , an exhaust port 3 , and a head water jacket 20 for allowing engine cooling water 3 to pass around the intake port 2 and the exhaust port 3 .

[0044] Therefore, there is an advantage that the cylinder head 6 can be cooled strongly by the engine cooling water 36 .

[0045] like Figure 1A As shown, the installation direction of the crankshaft 8 is the front-to-back direction, the width direction of the cylinder head 6 orthogonal to the front-to-back direction is the lateral direction, one lateral end of the cylinder head 6 is the exhaust end 6a, and the other lateral end is the intake end 6b.

[0046] The exhaust port 3 has a first exhaust valve port 3a and a second exhaust valve port 3b closer to the exhaust end 6a than the first exhaust valve port 3a, and the exhaust port wall has a first exhaust inlet port wall 3d close to the first exhaust valve port 3a and a second exhaust inlet port wall 3e close to the second exhaust valve port 3b.

[0047] The cover water jacket 20 has an exhaust port inter-wall water passage 29 between the first exhaust inlet port wall 3d and the second exhaust inlet port wall 3e.

[0048] The cylinder head 6 has a cooling water injection passage 27 disposed on the bottom wall 6c of the cylinder head 6. The cooling water injection passage 27 is offset toward the exhaust end 6a and has a passage inlet 27a close to the exhaust end 6a and a passage outlet 27b facing the exhaust port inter-wall water passage 29.

[0049] The exhaust port wall has fins 28 extending from the first exhaust inlet port wall 3d toward the exhaust end 6a side. The space between the fins 28 and the second exhaust inlet port wall 3e forms a water channel inlet 29a of the exhaust port inter-wall water channel 29 .

[0050] The engine cooling water 36 floating from the exhaust side of the cylinder water jacket 19 is introduced into the passage inlet 27 a of the cooling water injection passage 27 .

[0051] Therefore, if Figure 1A As shown, in the present embodiment, the bottom wall 6c of the cylinder head 6 near the exhaust end 6a where the heat load is high is strongly cooled by the engine cooling water 36 passing through the cooling water injection passage 27. In addition, the first exhaust inlet port wall 3d and the second exhaust inlet port wall 3e where the heat load is high are strongly cooled by the engine cooling water 36 injected from the cooling water injection passage 27. Therefore, insufficient cooling on the exhaust side is improved, thereby suppressing thermal deformation of the cylinder head 6.

[0052] In addition, due to the heat dissipation of the heat dissipation fins 28, the heat dissipation performance of the first exhaust gas inlet port wall 3d is high.

[0053] Moreover, if Figure 1A As shown, the engine cooling water 36 does not spread in a direction away from the exhaust port wall water channel 29 due to the heat sink 28, and can smoothly flow into the exhaust port wall water channel 29, thereby improving the cooling performance of the first exhaust inlet port wall 3d and the second exhaust inlet port wall 3e.

[0054] Furthermore, the engine cooling water 36 near the water channel inlet 29a of the exhaust port inter-wall water channel 29 is introduced into the water channel inlet 29a by the flow of the engine cooling water 36 injected from the cooling water injection passage 27. The engine cooling water 36 floated from the inter-cylinder bore water channel of the cylinder water jacket 19 through the floatation hole 39 is also introduced into the water channel inlet 29a.

[0055] like Figure 1A As shown, the water channel outlet 29 b of the exhaust port inter-wall water channel 29 faces the fuel injector 15 .

[0056] Therefore, if Figure 1A As shown, in the present embodiment, the engine cooling water 36 passing through the exhaust port inter-wall water passage 29 is directed toward the fuel injector 15 , so that the cooling performance of the fuel injector 15 is high.

[0057] like Figure 1A As shown, the air intake port wall has an air intake outlet port wall 2b close to the air intake valve port 2a, and the cover water jacket 20 has an air intake and exhaust port wall water channel 30 between the air intake outlet port wall 2b and the second exhaust inlet port wall 3e.

[0058] The cylinder head 6 has a second cooling water injection passage 31 provided on the bottom wall 6c of the head water jacket 20. The second cooling water injection passage 31 has a second passage inlet 31a near the exhaust end 6a and a second passage outlet 31b facing the water passage inlet 30a of the intake and exhaust port inter-wall water passage 30.

[0059] Therefore, if Figure 1AAs shown, in this embodiment, the second exhaust inlet port wall 3e with a high heat load is strongly cooled by the engine cooling water 36 injected from the second cooling water injection passage 31, so that the temperature difference between it and the intake outlet port wall 2b with a low heat load becomes smaller, thereby suppressing the thermal deformation of the cylinder head 6.

[0060] The engine cooling water 36 floating up from the exhaust side of the water jacket 19 is introduced into the second passage inlet 31 a of the second cooling water injection passage 31 .

[0061] like Figure 1A As shown, the second cooling water injection passage 31 is biased toward the exhaust end 6a side.

[0062] Therefore, if Figure 1A As shown, in this embodiment, the bottom wall 6c of the cylinder head 6 close to the exhaust end 6a with high heat load is strongly cooled by the engine cooling water 36 through the second cooling water injection passage 31, so that insufficient cooling on the exhaust side is improved, thereby suppressing thermal deformation of the cylinder head 6.

[0063] like Figure 1A As shown in FIG. , C, the cylinder head 6 has a second cooling fin 32 along the lower surface 6 f of the top wall 6 d of the cylinder head 6 .

[0064] A throttle passage 32 a is provided between the second fin 32 and the bottom wall 6 c of the cylinder head 6 . The throttle passage 32 a is disposed on the upstream side of the intake and exhaust port inter-wall water passage 30 in the water flow direction.

[0065] Therefore, if Figure 1A As shown in Figure , C, in the present embodiment, the engine cooling water 36 toward the water channel inlet of the water channel 30 between the intake and exhaust port walls is deflected toward the bottom wall 6c side of the cylinder head 6 due to the second heat sink 32, so that the side of the second exhaust valve port 3b close to the second exhaust inlet port wall 3e with a high heat load is strongly cooled, thereby improving the cooling performance of the second exhaust inlet port wall 3e.

[0066] like Figure 1A As shown in FIG. 3C, the cylinder head 6 has a push rod chamber wall 6e arranged on the exhaust end 6a side at a position opposite to the intake valve shaft insertion through boss 2c, and the second heat sink 32 is installed between the intake valve shaft insertion through boss 2c and the push rod chamber wall 6e.

[0067] Therefore, if Figure 1A As shown in FIG. 3 and C, in the present embodiment, the heat of the push rod chamber wall 6e arranged on the exhaust end 6a side is dissipated to the intake valve shaft inserted through the boss 2c via the second heat sink 32, so that the temperature difference between the exhaust side and the intake side of the cylinder head 6 is reduced, thereby suppressing the thermal deformation of the cylinder head 6.

[0068] like Figure 1AAs shown, the second fin 32 is farther away from the intake and exhaust port inter-wall water channel 30 than the second channel outlet 31 b of the second cooling water injection channel 31 .

[0069] Therefore, if Figure 1A As shown, in the present embodiment, the backflow of the floating engine cooling water 36 which is injected from the second passage outlet 31b of the second cooling water injection passage 31 and heated due to the heat absorption at the water passage inlet 30a of the water passage between the intake and exhaust port walls is blocked by the second heat sink 32, thereby suppressing the reduction in the flow rate of the engine cooling water 36 passing through the water passage between the intake and exhaust port walls 30, thereby improving the cooling performance of the second exhaust inlet port wall 3e.

[0070] like Figure 1A As shown, the water channel outlet 30 b of the intake and exhaust port inter-wall water channel 30 faces the fuel injector 15 .

[0071] Therefore, if Figure 1A As shown, in the present embodiment, the engine cooling water 36 flowing out from the intake and exhaust port inter-wall water passage 30 is directed toward the fuel injector 15 , so that the cooling performance of the fuel injector 15 is high.

[0072] like Figure 2 As shown, there is a head gasket 33 sandwiched between the cylinder block 5 and the cylinder head 6 .

[0073] The bottom wall 6 c of the cylinder head 6 has a combustion chamber top wall 34 and a pressing wall 35 which is located on the outer peripheral side of the combustion chamber top wall 34 and presses the bead 33 a of the head gasket 33 .

[0074] In the bottom wall 6 c of the cylinder head 6 , the pressing wall 35 is thicker than the outer peripheral portion 34 a of the combustion chamber top wall 34 adjacent to the pressing wall 35 .

[0075] Therefore, if Figure 2 As shown, in the present embodiment, the peripheral portion 34a of the combustion chamber top wall 34 with a high heat load is thin-walled, and therefore, it is possible to store heat, thereby making it difficult for the pressing wall 35 to be offset toward the outside in the cylinder diameter direction due to the thermal expansion of the combustion chamber top wall 34. Since the pressing wall 35 pressed against by the molding 33a is thick-walled, it is difficult for a depression to be caused by the reaction force of the molding 33a, thereby improving the sealing performance of the cover gasket 33.

[0076] Figure 2 Reference numeral 15a in the drawing denotes a fuel injector cover, 34b denotes a fuel injector insertion through-boss, and 40 denotes a combustion chamber.

[0077] Reference numeral 37 in FIG1 is a second air intake valve port disposed closer to the air intake end 6b than the air intake valve port 2a, 37a is a second air intake outlet port wall, the air intake valve port 2a is a spiral air intake port, and the second air intake valve port 37 is a tangential air intake port. In addition, reference numeral 38 is an air intake port wall waterway between the air intake outlet port wall 2b and the second air intake outlet port wall 37a.

Claims

1. A water-cooled engine, characterized in that: A cylinder head (6) is provided, The cylinder head (6) has an intake port (2), an exhaust port (3), and a head water jacket (20) for allowing engine cooling water (36) to pass around the intake port (2) and the exhaust port (3). The crankshaft (8) is mounted in a front-to-rear direction, the width direction of the cylinder head (6) perpendicular to the front-to-rear direction is defined as a transverse direction, one transverse end of the cylinder head (6) is defined as an exhaust end (6a), and the other transverse end is defined as an intake end (6b), The cylinder head (6) has a cooling water injection passage (27) provided on a bottom wall (6c) of the cylinder head (6), and the cooling water injection passage (27) is configured to inject engine cooling water (36) into a head water jacket (20) biased toward an exhaust end (6a) side. The cylinder head (6) comprises: an intake valve shaft insertion through boss (2c); a push rod chamber wall (6e) arranged on the exhaust end (6a) side at a position opposite to the intake valve shaft insertion through boss (2c); and a heat sink (32) extending from the push rod chamber wall (6e) to the intake valve shaft insertion through boss (2c).

2. The water-cooled engine according to claim 1, characterized in that: The air intake port wall of the air intake port (2) has an air intake outlet port wall (2b) close to the air intake valve port (2a), and the cover water jacket (20) has an air intake and exhaust port wall water channel (30) between the air intake outlet port wall (2b) and the exhaust inlet port wall (3e). The cylinder head (6) has a second cooling water injection passage (31) provided on a bottom wall (6c) of a head water jacket (20), the second cooling water injection passage (31) having a second passage inlet (31a) close to an exhaust end (6a) and a second passage outlet (31b) facing a water passage inlet (30a) of an inter-wall water passage (30) at an intake and exhaust port. A heat sink (32) is arranged along the lower surface (6f) of the top wall (6d) of the cylinder head (6), A throttling passage (32a) is provided between the mounting heat sink (32) and the bottom wall (6c) of the cylinder head (6). The throttling passage (32a) is arranged on the second passage outlet (31b) side of the second cooling water injection passage (31) which is on the upstream side of the water flow direction of the water passage (30) between the intake and exhaust port walls. When viewed from the top wall (6d) side of the cylinder head (6), the second passage outlet (31b) faces the water passage inlet (30a) of the water passage (30) between the intake and exhaust port walls in a direction intersecting the mounting heat sink (32).

3. The water-cooled engine according to claim 2, characterized in that: The heat sink (32) is mounted further away from the air intake and exhaust port inter-wall water channel (30) than the second channel outlet (31b) of the second cooling water injection channel (31).

4. The water-cooled engine according to claim 2 or 3, characterized in that: The second cooling water injection passage (31) is biased toward the exhaust end (6a) side.

5. The water-cooled engine according to claim 2 or 3, characterized in that: The water channel outlet (30b) of the water channel (30) between the intake and exhaust port walls faces the fuel injector (15).

6. The water-cooled engine according to claim 1, characterized in that: The exhaust port (3) has a first exhaust valve port (3a) and a second exhaust valve port (3b) closer to the exhaust end (6a) than the first exhaust valve port (3a); an exhaust port wall of the exhaust port (3) has a first exhaust inlet port wall (3d) close to the first exhaust valve port (3a) and a second exhaust inlet port wall (3e) close to the second exhaust valve port (3b); The cover water jacket (20) has an exhaust port wall water channel (29) between the first exhaust inlet port wall (3d) and the second exhaust inlet port wall (3e). The cooling water injection passage (27) has a passage inlet (27a) close to the exhaust end (6a) and a passage outlet (27b) toward the exhaust port inter-wall water passage (29). The exhaust port wall (3c) has an outlet heat sink (28) extending from the first exhaust inlet port wall (3d) toward the exhaust end (6a) side, and the outlet heat sink (28) and the second exhaust inlet port wall (3e) form a water channel inlet (29a) of the exhaust port inter-wall water channel (29). When viewed in a direction perpendicular to the bottom wall (6c) of the cylinder head (6), the outlet heat sink (28) is a curved shape in which the water channel inlet (29a) side of the exhaust port inter-wall water channel (29) is recessed.

7. The water-cooled engine according to claim 6, characterized in that: The water channel outlet (29b) of the exhaust port inter-wall water channel (29) faces the fuel injector (15).

8. The water-cooled engine according to any one of claims 1 to 3, characterized in that: A head gasket (33) is sandwiched between a cylinder block (5) and a cylinder head (6), The bottom wall (6c) of the cylinder head (6) comprises: a combustion chamber top wall (34); a pressing wall (35) located on the outer peripheral side of the combustion chamber top wall (34) and pressing a pressure strip (33a) of a head gasket (33); In a bottom wall (6c) of a cylinder head (6), a pressing wall (35) is thicker than an outer peripheral portion (34a) of a combustion chamber top wall (34) adjacent to the pressing wall (35).

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