Water-cooled engine

Abstract

To provide a water-cooled engine where engine cooling performance is increased.SOLUTION: A water-cooled engine includes a bleeding passage 10 led from an upper part of an impeller chamber 8a of a water pump 8 in a horizontal direction or in an upward direction to a bypass water path 6, and an air passage part 3a for passing air from a valve upstream side of a thermostat valve 3 to a valve downstream side. During time when supplying engine cooling water 9 from a water supply port 7a of a radiator 7 while stopping the engine, air 11 attempting to stay in the upper part of the impeller chamber 8a of the water pump 8 is pushed out from the upper part of the impeller chamber 8a through the bleeding passage 10 to the bypass water path 6 by rise of a water level in a cooling water circulation pathway 1, and pushed out from the water supply port 7a of the radiator 7 via the bypass water path 6, the air passage part 3a and a main water path 5 in sequence.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a water-cooled engine, and more particularly to a water-cooled engine with enhanced cooling performance of the engine.

Background Art

[0002] Conventionally, as a water-cooled engine, there is one provided with a cooling water circulation path of the engine by a water pump. (For example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] <<Problems>> The cooling performance of the engine may deteriorate. In the engine of Patent Document 1, during the water supply of the engine cooling water from the water supply port of the radiator performed while the engine is stopped, air that tries to accumulate in the impeller chamber of the water pump cannot be removed. Therefore, during engine operation, a decrease in cooling performance due to the circulation of air in the cooling water circulation path may occur, and the cooling performance of the engine may deteriorate.

[0005] An object of the present invention is to provide a water-cooled engine with enhanced cooling performance of the engine.

Means for Solving the Problems

[0006] The main configuration of the present invention is as follows. As illustrated in FIG. 1, an air vent passage (10) that is led out horizontally or in an upward direction from the upper part of the impeller chamber (8a) of the water pump (8) and reaches the bypass water passage (6), and an air passage portion (3a) that allows air to pass from the upstream side of the valve to the downstream side of the valve of the thermostat valve (3). During the supply of engine cooling water (9) from the water supply port (7a) of the radiator (7) while the engine is stopped, air (11) that attempts to accumulate above the impeller chamber (8a) of the water pump (8) is pushed out from above the impeller chamber (8a) through the air vent passage (10) and into the bypass water passage (6) due to the rising water level in the cooling water circulation path (1). It is configured to be pushed out from the water supply port (7a) of the radiator (7) via the air passage portion (3a) and the main water passage (5) in sequence from the bypass water passage (6). A water-cooled engine characterized by this. For other components of the invention of the present application, refer to claims 1 to 6.

Effect of the Invention

[0007] The present invention of the application has the following effects. 《Effect》 The cooling performance of the engine is enhanced. In this engine, during the supply of engine cooling water (9), due to the rising water level in the cooling water circulation path (1), air (11) that attempts to accumulate above the impeller chamber (8a) of the water pump (8) is pushed out from the water supply port (7a) of the radiator (7). Since it is difficult for air (11) to remain in the engine cooling water circulation path (1), during engine operation, it is difficult for the cooling performance to decrease due to the circulation of air (11) in the cooling water circulation path (1), and the cooling performance of the engine is enhanced. 《Effect》 Damage to the cooling water circulation path (1) is less likely to occur. In this engine, during engine operation, since it is difficult for air (11) to circulate in the cooling water circulation path (1), damage to the cooling water circulation path (1) due to cavitation is less likely to occur.

Brief Explanation of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0009] Figures 1 to 10 are diagrams for explaining a water-cooled engine according to an embodiment of the invention. In this embodiment, a vertical four-cycle in-line four-cylinder diesel engine will be described.

[0010] As shown in FIG. 10, this engine includes a cylinder block (27), a cylinder head (17) assembled to the upper part of the cylinder block (27), a head cover (17d) assembled to the upper part of the cylinder head (17), a crankshaft (13) housed in the crankcase (27c) of the cylinder block (27), a gear case (53) assembled to the front side of the cylinder block (27) with the erection direction of the crankshaft (13) being the front-rear direction, one side of the front-rear direction being the front and the other being the rear, an engine cooling fan (14) disposed on the front side of the gear case (53), and a flywheel (54) attached to the crankshaft (13) on the rear side of the cylinder block (27). The engine cooling fan (14) blows the engine cooling air (15) backward.

[0011] As shown in FIG. 3(B), when viewed in a direction parallel to the cylinder central axis line (16a), with the width direction of the cylinder head (17) perpendicular to the front-rear direction being the lateral direction, as shown in FIGS. 8 and 9, an intake manifold (55) is provided on one side in the lateral direction of the cylinder head (17), and an exhaust manifold (56) is provided on the other side. This engine includes an intake device, a fuel supply device, an exhaust device, a valve operating device, an interlocking shaft, a lubrication device, and a water cooling device.

[0012] As shown in FIG. 10, the intake device includes an air cleaner (57), an air compressor (49b) of a supercharger (49) attached to the upper part of the exhaust manifold (56), a supercharging pipe (49c), and the intake manifold (55) shown in FIG. 5. The air purified by the air cleaner (57) shown in FIG. 10 is compressed by the air compressor (49b) and supercharged from the supercharging pipe (49c) to the intake manifold (55) shown in FIG. 5.

[0013] As shown in Fig. 5, the fuel supply device includes a fuel tank (58), a fuel supply pump (59), a common rail (60), a fuel injector (61), and an engine ECU (62). The electromagnetic valve of the fuel injector (61) is electrically connected to the engine ECU (62). The electromagnetic valve is opened for a predetermined time at a predetermined timing under the control of the engine ECU (62), and fuel (73) with a predetermined injection amount is injected from the fuel injector (61) into each cylinder (16) at a predetermined injection timing. The fuel (73) is light oil. ECU is an abbreviation for electronic control unit and is a microcomputer. The injection timing is set by the crank angle, and the crank angle is detected based on a pulse signal associated with the engine rotation formed by an electromagnetic pickup (63) electrically connected to the engine ECU (62).

[0014] As shown in Fig. 10, the exhaust device includes an exhaust manifold (56), an exhaust turbine (49d) of the supercharger (49), and an exhaust treatment device (74). The exhaust gas discharged from the exhaust manifold (56) is processed by a DOC and a DPF (not shown) in the exhaust treatment device (74) after driving the exhaust turbine (49d). DOC is an abbreviation for diesel oxidation catalyst, and DPF is an abbreviation for diesel particulate filter.

[0015] As shown in Figs. 8 and 9, the valve operating device includes a valve operating camshaft (64) and an intake / exhaust valve (not shown) driven by the valve operating camshaft (64). The valve operating camshaft (64) is interlocked from the crankshaft (13) Time adjustment transmission gear train (not shown). The crankshaft (13) Time adjustment transmission gear train also interlocks a pair of left and right secondary balancer shafts (65)(65) via

[0016] As shown in Fig. 5, the lubrication device includes an oil pan (34), an oil strainer (66), an oil pump (35), an accessory mounting base (36), a base oil supply passage (38) for supplying engine oil (37) from the oil pump (35) to the accessory mounting base (36), a crankshaft oil supply passage (39) for supplying engine oil (37) from the base oil supply passage (38) to the bearing portion (13a) of the crankshaft (13), and as shown in Fig. 8, a pair of balancer shaft oil supply passages (67)(67) for supplying engine oil (37) to the bearing portions (65a) of the pair of left and right secondary balancer shafts (65)(65) via the crankshaft oil supply passage (39), and a camshaft oil supply passage (68) for supplying engine oil (37) from the bearing portion (65a) of the secondary balancer shaft (65) on the exhaust end side to the bearing portion (64a) of the valve camshaft (64). An oil cooler (19) and an oil filter (44) are attached to the accessory mounting base (36). The oil cooler (19) is arranged at a position higher than that of the oil filter (44).

[0017] As shown in Fig. 1, the water cooling device includes a cooling water circulation path (1) of the engine. The cooling water circulation path (1) of the engine includes a water jacket (2) in the engine, a valve housing case (4) housing a thermostat valve (3), a main water passage (5), a radiator (7), a water pump (8), and a bypass water passage (6).

[0018] During engine operation, when the thermostat valve (3) closes, which occurs when the water temperature of the engine cooling water in the water jacket (2) is lower than a predetermined temperature, all of the engine cooling water (9) in the water jacket (2) bypasses the radiator (7) and returns to the water jacket (2) via the valve housing case (4), the bypass water passage (6), and the water pump (8) in sequence. During engine operation, when the thermostat valve (3) opens due to the engine coolant (9) in the water jacket (2) having a temperature higher than a predetermined temperature, most of the engine coolant (9) in the water jacket (2) returns to the water jacket (2) via the valve housing case (4), the main water passage (5), the radiator (7), and the water pump (8) in sequence. At the same time, a part of the engine coolant (9) in the water jacket (2) bypasses the radiator (7) and returns to the water jacket (2) via the valve housing case (4), the bypass water passage (6), and the water pump (8) in sequence. That is, as shown in FIG. 1, during engine operation, this engine is configured such that a predetermined amount of the engine coolant (9) in the water jacket (2) bypasses the radiator (7) and returns to the water jacket (2) via the valve housing case (4), the bypass water passage (6), and the water pump (8) in sequence by the pumping force of the water pump (8).

[0019] As shown in FIG. 1, this engine is provided with an air bleeding passage (10) that is led out horizontally or in an upward direction from the upper part of the impeller chamber (8a) of the water pump (8) and reaches the bypass water passage (6), and an air passage part (3a) that allows air to pass from the upstream side to the downstream side of the valve of the thermostat valve (3). During the supply of the engine coolant (9) from the water supply port (7a) of the radiator (7) performed during engine stoppage, the air (11) that tries to accumulate in the upper part of the impeller chamber (8a) of the water pump (8) is pushed out from the upper part of the impeller chamber (8a) through the air bleeding passage (10) into the bypass water passage (6) due to the rise in the water level of the coolant circulation path (1), and is pushed out from the water supply port (7a) of the radiator (7) via the air passage part (3a) and the main water passage (5) in sequence from the bypass water passage (6).

[0020] In this engine, during the supply of engine cooling water (9), as the water level in the cooling water circulation path (1) rises, air (11) that attempts to accumulate in the upper part of the impeller chamber (8a) of the water pump (8) is pushed out from the water inlet (7a) of the radiator (7). Since it is difficult for the air (11) to remain in the engine cooling water circulation path (1), during engine operation, it is difficult for the cooling performance to decrease due to the circulation of the air (11) in the cooling water circulation path (1), and the cooling performance of the engine is enhanced. Also, in this engine, during engine operation, since it is difficult for the air (11) to circulate in the cooling water circulation path (1), it is difficult for the cooling water circulation path (1) to be damaged due to cavitation.

[0021] As shown in FIG. 1, in this embodiment, the air bleeding passage (10) is formed by a drilling hole that is led out horizontally from the impeller chamber (8a) and reaches the bypass water passage (6). The air passage portion (3a) is formed in the thermostat valve (3). However, the present invention is not limited to this. The air bleeding passage (10) may be led out obliquely upward or vertically upward from the impeller chamber (8a), and the air passage portion (3a) may be provided in the valve housing case (4). Note that the pump housing (8b) of the water pump (8), the end portion of the water passage wall (6a) of the bypass water passage (6), and the passage wall (10a) of the air bleeding passage (10) installed therebetween are integrally formed of a continuous metal material, and a drilling hole air bleeding passage (10) is formed in the passage wall (10a) of the air bleeding passage (10).

[0022] As shown in FIG. 1, this engine includes a reserve tank (12) connected to the water inlet (7a) of the radiator (7). In this engine, since it is difficult for the air (11) to remain in the cooling water circulation path (1), the amount of the engine cooling water (9) in the reserve tank (12) exchanged with the air (11) is reduced, and the replenishment frequency of the engine cooling water (9) to the reserve tank (12) can be decreased.

[0023] As shown in Fig. 1, the radiator (7) includes an upper tank (7b), a lower tank (7c), and horizontally arranged vertical heat dissipation pipes (7d) therebetween. The upper tank (7b) is connected to the valve housing case (4) via the main water passage (5), and the lower tank (7c) is connected to the water pump (8) via the return water passage (72). The water inlet (7a) is provided in the upper tank (7b) and covered with a radiator cap (7e).

[0024] As shown in Fig. 1, the radiator cap (7e) is provided with a valve mechanism (7f). During engine operation, when the volume of the engine cooling water (9) in the cooling water circulation path (1) expands due to a temperature rise and the internal pressure of the cooling water circulation path (1) increases, the main pressure valve of the valve mechanism (7f) opens, and a part of the engine cooling water (9) in the cooling water circulation path (1) overflows and accumulates in the reserve tank (12). After the engine stops and the internal pressure of the cooling water circulation path (1) decreases due to a temperature drop, the negative pressure valve of the valve mechanism (7f) opens, and a part of the engine cooling water (9) accumulated in the reserve tank (12) is drawn back into the cooling water circulation path (1).

[0025] As shown in Figs. 3(A) and (B), the water jacket (2) includes a cylinder jacket (2a) around the cylinder (16) and a head jacket (2b) in the cylinder head (17). As shown in Fig. 3(A), the cylinder jacket (2a) has a jacket inlet (2c) at the front end. As shown in Fig. 3(B), the head jacket (2b) has a jacket outlet (2d) at the front end. Between the cylinder jacket (2a) and the head jacket (2b), there are provided a plurality of water floating upper ports (18) opened on the peripheral side of each cylinder (16). Through the plurality of water floating upper ports (18), the engine cooling water (9) floats from the cylinder jacket (2a) to the head jacket (2b). The head jacket (2b) includes a rear-end side jacket portion (2ba) facing the rear-end side water floating upper port (18a) located in the rear-end side head portion (17a) of the cylinder head (17) among the plurality of water floating upper ports (18). As shown in Fig. 2, this engine includes a water-cooled oil cooler (19), a cooler water supply pipe (20) from the head jacket (2b) to the oil cooler (19), and a cooler drain pipe (21) from the oil cooler (19) to the water pump (8). The cooler water supply pipe (20) is led out from the rear-end side jacket portion (2ba).

[0026] In this engine, since the suction force of the water pump (8) acts on the rear-end side jacket portion (2ba) through the cooler drain pipe (21), the oil cooler (19), and the cooler water supply pipe (20) in sequence, a large amount of engine cooling water (9) is sucked up from the rear-end side water floating upper port (18a) to the rear-end side jacket portion (2ba), and the cooling performance of the rear-end side head portion (17a) where the engine cooling water (9) is originally difficult to float is improved. Also, in this engine, since a large amount of engine cooling water (9) floats from the rear-end side water floating upper port (18a) to the rear-end side jacket portion (2ba), for this purpose, there is no need to reduce the passage cross-sectional area of the other water floating upper ports (18), the passage resistance of the cooling water circulation path (1) can be reduced, and the cooling performance of the engine is enhanced.

[0027] As shown in Fig. 2, the cooler water supply pipe (20) is led out from the upper-end side portion (2bb) of the rear-end side jacket portion (2ba). In this engine, when the engine is inclined downward in the front, air (11) and water vapor that tend to accumulate in the upper-end side portion (2bb) of the rear-end side jacket portion (2ba) are sucked out through the cooler water supply pipe (20), so it is difficult for air (11) and water vapor to stagnate in the rear-end side jacket portion (2ba), and the cooling performance of the rear-end side head portion (17a) is enhanced.

[0028] As shown in Fig. 3(B), among the both lateral sides, with the inlet (22a) side of the intake port (22) being the intake end side and the outlet (32a) side of the exhaust port (32) being the exhaust end side, the cooler water supply pipe (20) is led out from the intake end side portion (2bc) of the rear-end side jacket portion (2ba). In this engine, since the relatively low-temperature engine cooling water (9) in the intake end side portion (2bc) of the rear end side jacket portion (2ba) is supplied from the cooler feed pipe (20) to the oil cooler (19), the cooling performance of the oil cooler (19) is enhanced.

[0029] As shown in FIG. 3(B), the head jacket (2b) includes, among a plurality of upper inter-bore water passages (23) located above the cylinder bores, a rear end side upper inter-bore water passage (23a) closer to the rear end of the cylinder head (17), among a plurality of water floating upper ports (18), a rear end side water floating upper port (18b) that supplies the engine cooling water (9) to the rear end side upper inter-bore water passage (23a), a rear end side jacket portion (2bd) facing the rear end side water floating upper port (18b), and a partition wall (24). The rear end side jacket portion (2bd) is disposed on the front side of the rear end side jacket portion (2ba), and the partition wall (24) is disposed between the rear end side jacket portion (2bd) and the rear end side jacket portion (2ba). In this engine, the engine cooling water (9) that has risen from the rear end side water floating upper port (18b) to the rear end side jacket portion (2bd) is blocked by the partition wall (24) and is supplied to the rear end side upper inter-bore water passage (23a) without being sucked into the cooler feed pipe (20) led out from the rear end side jacket portion (2ba), so that the cooling performance of the rear end side head portion (17b) of the cylinder head (17) is enhanced. As shown in FIG. 3(B), the rear end side upper inter-bore water passage (23a) is located between the rearmost cylinder (16) and the cylinder (16) in front of it.

[0030] As shown in FIG. 3(C), in this engine, the partition wall (24) connects the lower peripheral wall (22b) of the intake port (22) and the head bottom wall (17c) of the cylinder head (17). In this engine, since the heat of the head bottom wall (17c) is radiated to the lower peripheral wall (22b) of the intake port (22) through the partition wall (24), the cooling performance of the head bottom wall (17c) is enhanced. In this engine, the rigidity of the head bottom wall (17c) is enhanced by the partition wall (24).

[0031] As shown in FIG. 3(B), the cylinder head (17) includes an upper inter-bore water passage (23) located above the cylinder bores, and head bolt bosses (25) arranged on both lateral sides of the upper inter-bore water passage (23) as shown in FIG. 4(A). The head bolt bosses (25) include head bolts (26) inserted therein, and the cylinder head (17) and the cylinder block (27) are fastened with a head gasket (28) sandwiched therebetween by the fastening force of the head bolts (26). The cylinder head (17) includes a reinforcing wall (29) along one of the pair of head bolt bosses (25)(25) arranged on both lateral sides of the upper inter-bore water passage (23), and a reinforcing rib (30) along the other head bolt boss (25). With the reinforcing wall (29), the bottom wall (23b) of the upper inter-bore water passage (23) and the jacket ceiling wall (2be) of the head jacket (2b) are connected. The reinforcing rib (30) bulges from the bottom wall (23b) of the water passage toward the jacket ceiling wall (2be).

[0032] In this engine, since the heat of the bottom wall (23b) of the water passage is dissipated to the engine cooling water (9) passing through the upper inter-bore water passage (23) from the reinforcing wall (29) and the reinforcing rib (30), the cooling performance of the bottom wall (23b) of the water passage is enhanced. Also, in this engine, since the fastening force of the head bolts (26) is transmitted to the bottom wall (23b) of the water passage through the reinforcing wall (29) and the reinforcing rib (30), the sealing performance of the head gasket (28) is enhanced. Also, in this engine, the rigidity of the bottom wall (23b) of the water passage is enhanced by the reinforcing wall (29) and the reinforcing rib (30).

[0033] As shown in FIG. 4(B), the reinforcing wall (29) is connected to the peripheral wall (22c) of the intake port (22). In this engine, since the heat of the bottom wall (23b) of the water passage is dissipated to the peripheral wall (22c) of the intake port (22) through the reinforcing wall (29), the cooling performance of the bottom wall (23b) of the water passage is enhanced. In this engine, the rigidity of the water passage bottom wall (23b) is increased by a reinforcing wall (29) connected to the peripheral wall (22c) of the intake port (22).

[0034] As shown in FIGS. 4(A) and 4(C), the reinforcing rib (30) is disposed on a water passage bottom wall portion (23c) on the exhaust end side of the water passage bottom wall (23b). In this engine, the heat of the water passage bottom wall portion (23c) on the exhaust end side, which is prone to overheating, is conducted to the reinforcing rib (30) and dissipated to the engine cooling water (9) that passes through a large amount above the reinforcing rib (30). Therefore, the cooling performance of the water passage bottom wall portion (23c) on the exhaust end side is enhanced.

[0035] As shown in FIG. 4(A), the raised end face (30a) of the reinforcing rib (30) slopes downward from the head bolt boss (25) along the reinforcing rib (30) toward the reinforcing wall (29) side. For this reason, the fastening force of the head bolt (26) is transmitted to the water passage bottom wall portion (23c) on the exhaust end side via the reinforcing rib (30), and the heat of the water passage bottom wall portion (23c) on the exhaust end side is dissipated from the inclined and wide raised end face (30a) of the reinforcing rib (30) to the large amount of engine cooling water (9) flowing above the reinforcing rib (30), enhancing the cooling performance of the water passage bottom wall portion (23c) on the exhaust end side.

[0036] As shown in FIG. 4(A), this engine is provided with a pair of water lifting holes (31)(31) for lifting the engine cooling water (9) from the cylinder jacket (2a) to the head jacket (2b) on both lateral sides in the transverse direction of the water passage bottom wall (23b) of the between-bore upper water passage (23). Among the pair of water lifting holes (31)(31), the water lifting hole (31) on the exhaust end side is defined as the exhaust end side water lifting hole (31a), and the water lifting hole (31) on the intake end side is defined as the intake end side water lifting hole (31b). As shown in FIGS. 4(A) and 4(C), the exhaust end side water lifting hole (31a) is provided inside the reinforcing rib (30), and as shown in FIGS. 4(A) and 4(B), the intake end side water lifting hole (31b) is provided inside the reinforcing wall (29). As shown in FIG. 4(B), the water lifting hole outlet (31ba) of the intake end side water lifting hole (31b) is directed toward the exhaust port peripheral wall (32b). As shown in Fig. 4(B), in this engine, since the engine cooling water (9) flowing out from the water floating hole outlet (31ba) of the intake end side water floating hole (31b) is directed toward the exhaust port peripheral wall (32b), the cooling performance of the exhaust port peripheral wall (32b) is enhanced.

[0037] As shown in Fig. 4(A), the cylinder jacket (2a) includes an inter-bore water passage (33) provided between adjacent cylinder bores, a jacket portion (2aa) on the intake end side, and a jacket portion (2ab) on the exhaust end side. The engine cooling water (9) is sent from the jacket portion (2aa) on the intake end side to the jacket portion (2ab) on the exhaust end side through the inter-bore water passage (33). The inter-bore water passage (33) includes a first transverse water passage (33c) provided between the inter-bore ceiling wall (33a) and the first transverse wall (33b) directly below it, and a second transverse water passage (33e) provided between the first transverse wall (33b) and the second transverse wall (33d) directly below it. Since the intake end side wall portion (33ba) of the first transverse wall (33b) slopes downward toward the jacket portion (2aa) on the intake end side, the lower part (33ca) of the inlet of the first transverse water passage (33c) slopes downward toward the jacket portion (2aa) on the intake end side, and the upper part (33ea) of the inlet of the second transverse water passage (33e) is configured to slope downward toward the jacket portion (2aa) on the intake end side.

[0038] In this engine, as shown in Fig. 3(A), the jacket inlet (2c) on the front end side of the cylinder jacket (2a) faces the lateral center portion of the front surface of the front end side cylinder (16). The passage cross-sectional area of the jacket portion (2aa) on the intake end side is wider than that of the jacket portion (2ab) on the exhaust side. As shown in Fig. 3(B), since the jacket outlet (2d) on the front end side of the head jacket (2b) is arranged biased toward the exhaust end side, the engine cooling water (9) is sent from the jacket portion (2aa) on the intake end side to the jacket portion (2ab) on the exhaust end side through the inter-bore water passage (33).

[0039] In this engine, since the low-temperature engine cooling water (9) located below the jacket portion (2aa) on the intake end side is introduced upward along the inclinations of the lower part of the inlet (33ca) of the first transverse water passage (33c) and the upper part of the inlet (33ea) of the second transverse water passage (33e), the cooling performance between the cylinder bores is enhanced.

[0040] As shown in Fig. 4(A), the inter-bore water passage (33) includes a third transverse water passage (33g) provided between the second transverse wall (33d) and the third transverse wall (33f) directly below it. Since the intake-end side wall portion (33da) of the second transverse wall (33d) slopes downward toward the intake-side jacket portion (2aa), the lower part of the inlet (33eb) of the second transverse water passage (33e) slopes downward toward the intake-end side jacket portion (2aa), and the upper part of the inlet (33ga) of the third transverse water passage (33g) is configured to slope downward toward the intake-end side jacket portion (2aa). In this engine, since the low-temperature engine cooling water (9) located below the jacket portion (2aa) on the intake end side is introduced upward along the inclinations of the lower part of the inlet (33eb) of the second transverse water passage (33e) and the upper part of the inlet (33ga) of the third transverse water passage (33g), the cooling performance between the cylinder bores is enhanced.

[0041] As shown in Fig. 4(A), in this engine, the exhaust-end side water floating hole (31a) has a larger minimum passage cross-sectional area than the intake-end side water floating hole (31b). In this engine, since the flow of the engine cooling water (9) introduced from the jacket portion (2aa) on the intake end side through the inter-bore water passage (33) to the exhaust-end side water floating hole (31a) is promoted, the cooling performance between the cylinder bores is enhanced. The inter-bore water passage (33) includes a fourth transverse water passage (33k) provided between the third transverse wall (33f) and the fourth transverse wall (33h) directly below it. The fourth transverse water passage (33k) is formed in a horizontal direction.

[0042] As shown in FIG. 5, this engine includes an oil pan (34), an oil pump (35), an accessory mounting base (36) to which an oil cooler (19) is attached, a base oil supply passage (38) for supplying engine oil (37) in the oil pan (34) from the oil pump (35) to the accessory mounting base (36), and a crankshaft oil supply passage (39) for supplying the engine oil (37) cooled by the oil cooler (19) from the accessory mounting base (36) to the bearing portion (13a) of the crankshaft (13).

[0043] As shown in FIG. 6(B), in this engine, the accessory mounting base (36) includes an oil cooler oil supply port (40), an oil cooler oil supply passage (40a) led out from the oil cooler oil supply port (40), an oil cooler oil drain port (41), and an oil cooler oil drain passage (41a) led out from the oil cooler oil drain port (41). Of the oil cooler oil supply port (40) and the oil cooler oil drain port (41) having a height difference, the higher one is defined as the cooler high - level port (42), and the lower one is defined as the cooler low - level port (43). Of the oil cooler oil supply passage (40a) and the oil cooler oil drain passage (41a), the one led out from the cooler low - level port (43) is defined as the cooler low - level port oil passage (43a). The cooler low - level port oil passage (43a) is led upward to a height equal to or higher than the height of the lower edge (42a) of the cooler high - level port (42). The height equal to or higher than the height of the lower edge (42a) of the cooler high - level port (42) means a height equal to or higher than the height of the lower edge (42a) of the cooler high - level port (42).

[0044] In this engine, during engine shutdown, the engine oil (37) in the oil cooler (19) remains at least up to the height of the lower edge (42a) of the cooler high - level port (42). Therefore, when the engine is restarted, the engine oil (37) is supplied to the bearing portion (13a) of the crankshaft (13) via the crankshaft oil supply passage (39) in a short time, and seizure thereof is prevented.

[0045] As shown in FIG. 6(B), in this engine, among the oil cooler supply oil passage (40a) and the oil cooler drain oil passage (41a), the one led out from the cooler high-place port (42) is defined as the cooler high-place port oil passage (42c). When viewed in a direction parallel to the lateral direction, the cooler high-place port oil passage (42c) is led out downward from the cooler high-place port (42). During engine stoppage, the engine oil (37) in the oil cooler (19) flows down to the oil pan (34) side through the cooler high-place port (42), the cooler high-place port oil passage (42c), the filter low-place port oil passage (48a), the oil filter (44), and the base supply oil passage (38) in sequence. Therefore, it only remains up to the height of the lower edge (42a) of the cooler high-place port (42).

[0046] The cooler high-place port oil passage (42c) shown in FIG. 6(B) can be led out upward from the cooler high-place port (42) when viewed in a direction parallel to the lateral direction, and can also be led out upward to a height equal to or higher than the height of the lower edge (42a) of the cooler high-place port (42) and the cooler low-place port oil passage (43a). In this case, during engine stoppage, the engine oil (37) in the oil cooler (19) can remain up to the height of the lower edge of the upward leading end of the cooler low-place port oil passage (43a) that is the same as or exceeds the height of the lower edge (42a) of the cooler high-place port (42).

[0047] As shown in FIGS. 6(B) and (C), the cooler high-place port (42) is provided inside the pipe base end portion (42ba) inserted into the accessory mounting base (36) among the horizontally oriented pipes (42b) oriented in the lateral direction. As shown in FIG. 6(B), when viewed in a direction parallel to the lateral direction, after the cooler low-place port oil passage (43a) is led out upward from the cooler low-place port (43), it is led out downward to the oil passage inlet (39a) of the crankshaft supply oil passage (39).

[0048] As shown in FIG. 6(B), the oil cooler supply port (40) is the cooler high-place port (42), the oil cooler drain port (41) is the cooler low-place port (43), and the oil cooler drain oil passage (41a) is the cooler low-place port oil passage (43a). During engine operation, the engine oil (37) passing through the oil cooler (19) by the pumping force of the oil pump (35) smoothly descends within the oil cooler (19) while increasing its specific gravity due to the cooling of the oil cooler (19), thus reducing the pumping burden on the oil pump (35).

[0049] As shown in FIGS. 6(C) to (F), the oil cooler (19) is configured by alternately overlapping an oil passage layer (19b) through which the engine oil (37) passes and a water passage layer (19c) through which the engine cooling water (9) passes. As shown in FIG. 6(E), an oil partition wall (19ba) is provided in the oil passage layer (19b), and as shown in FIG. 6(F), a water partition wall (19ca) is provided in the water passage layer (19c). In the oil passage layer (19b), the engine oil (37) introduced from the upper rear oil cooler oil supply port (40) reverses downward and backward in front of the oil partition wall (19ba) and is discharged from the lower rear oil cooler oil drain port (41). In the water passage layer (19c), the engine cooling water (9) introduced from the lower front oil cooler water supply port (70) reverses upward and forward behind the water partition wall (19ca) and is discharged from the upper front oil cooler water drain port (71).

[0050] As shown in FIG. 5, this engine is equipped with an oil filter (44) attached to the accessory mounting base (36), and the engine oil (37) supplied to the accessory mounting base (36) is purified by the oil filter (44) and supplied to the oil cooler (19). As shown in FIGS. 6(B) and (C), the accessory mounting base (36) includes an oil filter oil supply port (45), an oil filter oil supply passage (45a) led out from the oil filter oil supply port (45), an oil filter oil drain port (46), and an oil filter oil drain passage (46a) led out from the oil filter oil drain port (46). Of the oil filter fuel inlet (45) and the oil filter drain outlet (46) with a height difference, the higher one is defined as the filter high point port (47), and the lower one is defined as the filter low point port (48). Among the oil filter fuel supply line (45a) and the oil filter drain line (46a), the one led out from the filter low point port (48) is defined as the filter low point port oil line (48a). The filter low point port oil line (48a) is led upward to a height equal to or higher than the height of the lower edge (47a) of the filter high point port (47). The height equal to or higher than the height of the lower edge (47a) of the filter high point port (47) means a height equal to or higher than the height of the lower edge (47a) of the filter high point port (47).

[0051] As shown in Fig. 6(C), in this engine, among the oil filter fuel supply line (45a) and the oil filter drain line (46a), the one led out from the filter high point port (47) is defined as the filter high point port oil line (47b). The filter high point port oil line (47b) is led out horizontally from the filter high point port (47). When the engine is stopped, the engine oil (37) in the oil filter (44) flows down to the oil pan (34) side sequentially through the filter high point port (47), the filter high point port oil line (47b), and the base fuel supply line (38), and only remains up to the height of the lower edge (47a) of the filter high point port (47).

[0052] The filter high point port oil line (47b) may be led out upward from the filter high point port (47) when viewed in a direction parallel to the horizontal direction. In this case, when the engine is stopped, the engine oil (37) in the oil filter (44) can remain up to the height of the lower edge of the upward leading end of the filter high point port oil line (47b) that is equal to or higher than the height of the lower edge (47a) of the filter high point port (47).

[0053] As shown in Fig. 6(C), the filter high point port (47) is provided at the oil outlet (47c) of the horizontal filter high point port oil line (47b) directed in the lateral direction of the accessory mounting base (36). As shown in Fig. 6(C), the filter high point port oil line (47b) is connected to the oil outlet (38a) of the base fuel supply line (38). As shown in Fig. 6(B), the filter low outlet oil passage (48a) is connected to the upward cooler high outlet oil passage (42c) after being led out upward from the filter low outlet (48).

[0054] In this engine, during engine stoppage, the engine oil (37) in the oil filter (44) remains at least up to the height of the lower edge (47a) of the filter high outlet (47). Therefore, when the engine is restarted, the engine oil (37) is supplied to the bearing portion (13a) of the crankshaft (13) via the crankshaft oil supply passage (39) in a short time, preventing seizure.

[0055] As shown in Fig. 6(B), the oil filter oil supply port (45) is the filter high outlet (47), the oil filter oil drain port (46) is the filter low outlet (48), and the oil filter oil drain passage (46a) is the filter low outlet oil passage (48a). In this engine, during engine operation, the engine oil (37) passing through the oil filter (44) by the pumping force of the oil pump (35) descends by its own weight inside the oil filter (44), so the burden of pumping by the oil pump (35) can be reduced.

[0056] The modified examples of the accessory mounting base (36) shown in Figs. 7(A) and (B) are as follows. Both the oil cooler oil supply passage (40a) and the oil cooler oil drain passage (41a) of the accessory mounting base (36) are led out upward to a height equal to or higher than the height of the uppermost part (19a) inside the cooler of the oil cooler (19).

[0057] The height equal to or higher than the height of the uppermost part (19a) inside the cooler of the oil cooler (19) means a height equal to or higher than the height of the uppermost part (19a) inside the cooler of the oil cooler (19).

[0058] In this engine, while the engine is stopped, the engine oil (37) in the oil cooler (19) remains filled in the oil cooler (19). Therefore, when the engine is restarted, the engine oil (37) is supplied to the bearing portion (13a) of the crankshaft (13) via the crankshaft oil supply passage (39) in a short time, and its seizure is prevented.

[0059] As shown in FIGS. 7(A) and 7(B), both the oil filter oil supply passage (45a) and the oil filter oil drain passage (46a) are led upward to a height equal to or higher than the height of the uppermost part (44a) inside the filter of the oil filter (44).

[0060] In this engine, while the engine is stopped, the engine oil (37) in the oil filter (44) remains filled in the oil filter (44). Therefore, when the engine is restarted, the engine oil (37) is supplied to the bearing portion (13a) of the crankshaft (13) via the crankshaft oil supply passage (39) in a short time, and its seizure is prevented.

[0061] Other configurations of the modified example of the accessory mounting base (36) shown in FIGS. 7(A) and 7(B) are the same as the basic example of the accessory mounting base (36) shown in FIGS. 6(A) to 6(F). In FIGS. 7(A) and 7(B), the same elements as those in FIGS. 6(A) to 6(F) are denoted by the same reference numerals.

[0062] As shown in FIG. 5, in this engine, the accessory mounting base (36) is attached to the rear side of the intake end side of the cylinder block (27). As shown in FIG. 9, an oil branch pipe (50) led out from the rear side of the accessory mounting base (36), a rear end wall transverse oil passage (27b) crossing inside the rear end wall (27a) of the cylinder block (27), and a supercharger oil supply pipe (51) for supplying engine oil (37) to the bearing portion (49a) of the supercharger (49) are provided. The engine oil (37) in the accessory mounting base (36) is configured to be supplied to the bearing portion (49a) of the supercharger (49) through the oil branch pipe (50), the rear end wall transverse oil passage (27b), and the supercharger oil supply pipe (51) in this order.

[0063] In this engine, engine oil (37) is supplied from the accessory mounting base (36) to the bearing portion (49a) of the supercharger (49) along the shortest path. Therefore, at engine startup, the engine oil (37) is supplied to the bearing portion (49a) of the supercharger (49) in a short time, preventing seizure thereof. Also, in this engine, at cold startup of the engine when the viscosity of the engine oil (37) increases, the engine oil (37) passing through the rear end wall transverse oil passage (27b) that traverses inside the rear end wall (27a) of the cylinder block (27) immediately after startup is heated by the combustion heat of the engine, resulting in a lower viscosity. Since the engine oil (37) is supplied to the bearing portion (49a) of the supercharger (49) without delay, seizure of the bearing portion (49a) of the supercharger (49) is also prevented during cold startup.

[0064] As shown in FIGS. 8 to 10, in this engine, a supercharger drain pipe (69) is led out from the bearing portion (49a) of the supercharger (49), and the engine oil (37) that lubricated the bearing portion (49a) of the supercharger (49) returns to the oil pan (34) via the supercharger drain pipe (69). The oil branch pipe (50), the supercharger supply pipe (51), and the supercharger drain pipe (69) are all external engine piping, and the rear end wall transverse oil passage (27b) is an internal engine oil passage.

[0065] As shown in FIG. 6(B), the engine oil (37) is branched from the oil cooler drain oil passage (41a) of the accessory mounting base (36) to the oil branch pipe (50). In this engine, since the engine oil (37) cooled by the oil cooler (19) is supplied to the bearing portion (49a) of the supercharger (49), seizure of the bearing portion (49a) of the supercharger (49) is prevented even when the engine is running at high speed with an increased rotational speed of the supercharger (49).

[0066] The structure of the modified example of the oil branch pipe (50) shown in FIG. 7(C) is as follows. The oil branch pipe (50) shown in Fig. 7(C) is attached with a check valve (52) shown in Fig. 7(D) to prevent the reverse flow of the engine oil (37) from the oil branch pipe (50) to the auxiliary machine mounting base (36). In this engine, during engine shutdown, the engine oil (37) in the oil branch pipe (50), the rear end wall cross oil passage (27b), and the supercharger oil supply pipe (51) shown in Fig. 9 do not leak to the auxiliary machine mounting base (36) side. Therefore, when the engine is restarted, the engine oil (37) is supplied to the bearing portion (49a) of the supercharger (49) in a short time, preventing seizure of the bearing portion (49a) of the supercharger (49). Note that the oil branch pipe (50) shown in Fig. 9 is led out from the oil filter drain port (46) on the upstream side of the oil cooler (19) in the flow path.

[0067] The modification example of the oil branch pipe (50) shown in Fig. 7(C) may be combined not only with the basic example of the auxiliary machine mounting base (36) shown in Fig. 6(B), but also with the modification example of the auxiliary machine mounting base (36) shown in Fig. 7(A).

Description of Reference Numerals

[0068] (1)…Cooling water circulation path, (2)…Water jacket, (2a)…Cylinder jacket, (2b)…Head jacket, (2ba)…Rear end side jacket portion, (2bb)…Upper end side portion, (2bc)…Intake end side portion, (2bd)…Jacket portion near the rear end, (2c)…Jacket inlet, (2d)…Jacket outlet, (3)…Thermostat valve, (3a)…Air passage portion, (4)…Valve housing case, (5)…Main water passage, (6)…Bypass water passage, (7)…Radiator, (7a)…Water inlet, (8)…Water pump, (8a)…Impeller chamber, (9)…Engine cooling water, (10)…Air vent passage, (11)…Air, (12)…Reserve tank, (16)…Cylinder, (16a)…Cylinder central axis line, (17)…Cylinder head, (17a)…Rear end side head portion, (17c)…Head bottom wall, (18)…Water float upper opening, (18a)…Rear end side water float upper opening, (18b)…Water float upper opening near the rear end, (19)…Oil cooler, (20)…Cooler water supply pipe, (21)…Cooler drain pipe, (22)…Intake port, (22a)…Inlet, (22b)…Lower peripheral wall, (23)…Upper water passage between bores, (23a)…Water float upper opening near the rear end, (24)…Partition wall, (32)…Exhaust port, (32a)…Outlet.

Claims

1. The cooling water circulation path (1) of the engine includes a water jacket (2) in the engine, a valve housing case (4) that houses a thermostat valve (3), a main water passage (5), a radiator (7), a water pump (8), and a bypass water passage (6). During engine operation, a predetermined amount of the engine cooling water (9) in the water jacket (2) bypasses the radiator (7) by the pumping force of the water pump (8) and returns to the water jacket (2) in sequence through the valve housing case (4), the bypass water passage (6), and the water pump (8). In the water-cooled engine configured as such, it is provided with an air bleeding passage (10) that is led out horizontally or in an upward direction from the upper part of the impeller chamber (8a) of the water pump (8) and reaches the bypass water passage (6), and an air passage portion (3a) that allows air to pass from the upstream side of the valve to the downstream side of the thermostat valve (3). During the supply of the engine cooling water (9) from the water supply port (7a) of the radiator (7) performed during engine stoppage, the air (11) that tends to accumulate in the upper part of the impeller chamber (8a) of the water pump (8) is pushed out from the upper part of the impeller chamber (8a) through the air bleeding passage (10) into the bypass water passage (6) due to the rise in the water level of the cooling water circulation path (1), and is pushed out from the water supply port (7a) of the radiator (7) in sequence through the air passage portion (3a) and the main water passage (5) from the bypass water passage (6). It is configured as such. The water-cooled engine is a vertical in-line multi-cylinder engine. With the installation direction of the crankshaft (13) being the front-rear direction, one side of the front-rear direction being the front and the other side being the rear, the water jacket (2) includes a cylinder jacket (2a) around the cylinder (16) and a head jacket (2b) in the cylinder head (17). The cylinder jacket (2a) has a jacket inlet (2c) at the front end, and the head jacket (2b) has a jacket outlet (2d) at the front end. Between the cylinder jacket (2a) and the head jacket (2b), a plurality of water floating upper openings (18) that are opened on the peripheral side of each cylinder (16) are provided. Through the plurality of water floating upper openings (18), the engine cooling water (9) floats from the cylinder jacket (2a) to the head jacket (2b). The head jacket (2b) includes a rear-end side jacket portion (2ba) that faces the rear-end side water floating upper opening (18a) located in the rear-end side head portion (17a) of the cylinder head (17) among the plurality of water floating upper openings (18). A water-cooled oil cooler (19), a cooler water supply pipe (20) from the head jacket (2b) to the oil cooler (19), and a cooler drain pipe (21) from the oil cooler (19) to the water pump (8) are provided. The cooler water supply pipe (20) is led out from the rear end side jacket portion (2ba), and the water-cooled engine is characterized by this.

2. In the water-cooled engine described in Claim 1, The cooler water supply pipe (20) is led out from the upper end side portion (2bb) of the rear end side jacket portion (2ba), and the water-cooled engine is characterized by this.

3. In the water-cooled engine of the engine described in Claim 1, When viewed in a direction parallel to the cylinder central axis line (16a), with the width direction of the cylinder head (17) orthogonal to the front-rear direction as the lateral direction, among both lateral sides, the inlet (22a) side of the intake port (22) is the intake end side, and the outlet (32a) side of the exhaust port (32) is the exhaust end side. The cooler water supply pipe (20) is led out from the intake end side portion (2bc) of the rear end side jacket portion (2ba), and the water-cooled engine is characterized by this.

4. In the water-cooled engine described in Claim 1, The head jacket (2b) includes, among a plurality of upper inter-bore water passages (23) located above the cylinder bores, a rear-end side upper inter-bore water passage (23a) closer to the rear end of the cylinder head (17), among a plurality of water floating upper openings (18), a rear-end side water floating upper opening (18b) that supplies engine cooling water (9) to the rear-end side upper inter-bore water passage (23a), a rear-end side jacket portion (2bd) facing the rear-end side water floating upper opening (18b), and a partition wall (24). The rear-end side jacket portion (2bd) is disposed on the front side of the rear end side jacket portion (2ba), and the partition wall (24) is disposed between the rear-end side jacket portion (2bd) and the rear end side jacket portion (2ba), and the water-cooled engine is characterized by this.

5. In the water-cooled engine described in Claim 4, The partition wall (24) connects the lower peripheral wall (22b) of the intake port (22) and the head bottom wall (17c) of the cylinder head (17), and the water-cooled engine is characterized by this.

6. In the water-cooled engine described in any one of Claims 1 to 5, A reserve tank (12) connected to the water supply port (7a) of the radiator (7) is provided, and the water-cooled engine is characterized by this.

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