engine

Abstract

To provide an engine in which seizure of a bearing part of a crank shaft is prevented when restarting the engine.SOLUTION: Higher one of an oil cooler oil supply port 40 and an oil cooler oil discharge port 41 having a difference in a height is set as a cooler high place port 42, and lower one is set as a cooler low plate port 43. One of an oil cooler oil supply path 40a and an oil cooler oil discharge path 41a, that is led from the cooler low place port 43, is set as a cooler low place port oil path 43a. The cooler low place port oil path 43a is led out upward to a height equal to or greater than a height of a lower edge 42a of the cooler high place port 42, so that engine oil 37 in an oil cooler 19 is left up to at least the height of the lower edge 42a of the cooler high place port 42 during engine stop.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an engine, and more particularly to an engine in which seizure of a bearing portion of a crankshaft is prevented when the engine is restarted. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there is an engine that is provided with an auxiliary equipment mounting base to which an oil cooler is attached (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-105277 A (see FIG. 1) Summary of the Invention [Problem to be solved by the invention]

[0004] [Problem] There is a risk of the crankshaft bearings seizing up when the engine is restarted. In the engine of Patent Document 1, while the engine is stopped, much of the engine oil in the oil cooler drains out. Therefore, when the engine is restarted, engine oil is not supplied to the crankshaft bearing until the oil cooler is filled with engine oil. If the supply time is long, there is a risk that the crankshaft bearing will seize.

[0005] An object of the present invention is to provide an engine in which seizure of the bearing portion of the crankshaft is prevented when the engine is restarted. [Means for solving the problem]

[0006] The main configuration of the present invention is as follows. (Invention according to claim 1) As shown in FIG. 6(B), the accessory mounting base (36) includes an oil cooler oil supply port (40), an oil cooler oil supply passage (40a) extending from the oil cooler oil supply port (40), an oil cooler oil drain port (41), and an oil cooler oil drain passage (41a) extending from the oil cooler oil drain port (41). An engine characterized in that, of an oil cooler oil supply port (40) and an oil cooler oil drain port (41), which are located at different heights, the higher one is designated as a cooler high-altitude port (42) and the lower one is designated as a cooler low-altitude port (43), and, of the oil cooler oil supply passage (40a) and the oil cooler drain passage (41a), the one leading out from the cooler low-altitude port (43) is designated as a cooler low-altitude port oil passage (43a), and the cooler low-altitude port oil passage (43a) is led out upward to a height equal to or higher than the height of a lower edge (42a) of the cooler high-altitude port (42). (Invention according to claim 5) As illustrated in FIGS. 7(A) and 7(B), the accessory mounting base (36) includes an oil cooler oil supply port (40), an oil cooler oil supply passage (40a) extending from the oil cooler oil supply port (40), an oil cooler oil drain port (41), and an oil cooler oil drain passage (41a) extending from the oil cooler oil drain port (41). The engine is characterized in that an oil cooler oil supply passage (40a) and an oil cooler oil discharge passage (41a) are both led upward to a height equal to or higher than the height of an inner uppermost portion (19a) of the oil cooler (19). Effect of the Invention

[0007] The present invention has the following advantages. (Invention according to claim 1) <Effect> When the engine is restarted, the bearing portion (13a) of the crankshaft (13) is prevented from seizing. In this engine, while the engine is stopped, 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-altitude opening (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, thereby preventing seizure thereof. (Invention according to claim 5) <Effect> The bearing portion (13a) of the crankshaft (13) is prevented from seizing when the engine is restarted. In this engine, while the engine is stopped, the engine oil (37) remains in the oil cooler (19) filling 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) through the crankshaft oil supply passage (39) in a short time, thereby preventing seizure thereof. [Brief description of the drawings]

[0008] [Figure 1] 1 is a front view of a cooling water circulation path for use in a water-cooled engine according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a side view of the cooling water circulation path in FIG. [Diagram 3] 3(A) is a plan view of a cylinder block used in the cooling water circulation path of FIG. 1, FIG. 3(B) is a plan view of a cylinder head, and FIG. 3(C) is a cross-sectional view taken along line CC of FIG. 3(B). [Figure 4] 4(A) is a cross-sectional view taken along line IV-IV in FIG. 3(A), FIG. 4(B) is a cross-sectional view taken along line BB in FIG. 4(A), FIG. 4(C) is a cross-sectional view taken along line CC in FIG. 4(A), and FIG. 4(D) is a cross-sectional view taken along line DD in FIG. 4(A). [Diagram 5] FIG. 2 is a side view of a fuel supply system and a lubrication system used in the water-cooled engine according to the embodiment of the present invention. [Figure 6] Figure 6(A) is a side view of a cylinder block used in a water-cooled engine according to an embodiment of the present invention, Figure 6(B) is a side view of an accessory mounting base, Figure 6(C) is a cross-sectional view taken along line CC in Figure 6(B), Figure 6(D) is a cross-sectional view taken along line DD in Figure 6(B), Figure 6(E) is a cross-sectional view taken along line EE in Figure 6(C), and Figure 6(F) is a cross-sectional view taken along line FF in Figure 6(D). [Figure 7] Figure 7(A) is a side view of a modified accessory mounting base, Figure 7(B) is a cross-sectional view along line BB in Figure 7(A), Figure 7(C) is a side view of a modified oil branch pipe, and Figure 7(D) is an enlarged cross-sectional view of part D in Figure 7(C). [Figure 8] 1 is a front view of a water-cooled engine according to an embodiment of the present invention. [Figure 9] FIG. 2 is a rear view of the water-cooled engine according to the embodiment of the present invention. [Figure 10] 1 is a side view of a water-cooled engine according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

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

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

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

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

[0014] As shown in FIG. 10, the exhaust system includes an exhaust manifold (56), an exhaust turbine (49d) of the turbocharger (49), and an exhaust treatment device (74). The exhaust gas discharged from the exhaust manifold (56) drives the exhaust turbine (49d) and is then treated by a DOC and a DPF (not shown) in the exhaust treatment device (74). DOC is an abbreviation for diesel exhaust catalyst, and DPF is an abbreviation for diesel particulate filter.

[0015] As shown in FIGS. 8 and 9, the valve gear includes a valve camshaft (64) and intake and exhaust valves (not shown) driven by the valve camshaft (64). The valve camshaft (64) is connected to the crankshaft (13) via a timing transmission gear drain (not shown). The crankshaft (13) is also interlocked with a pair of left and right secondary balancer shafts (65), (65) via a timing transmission gear drain.

[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) that supplies engine oil (37) from the oil pump (35) to the accessory mounting base (36), a crankshaft oil supply passage (39) that supplies the 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) that supply the engine oil (37) to each bearing portion (65a) of a pair of left and right secondary balancer shafts (65) (65) via the crankshaft oil supply passage (39), and a camshaft oil supply passage (68) that supplies the 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 disposed at a higher position than the oil filter (44).

[0017] As shown in FIG. 1, the water-cooling device includes a cooling water circulation path (1) for the engine. The engine cooling water circulation path (1) includes a water jacket (2) inside 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).

[0018] During engine operation, when the temperature of the engine cooling water in the water jacket (2) is lower than a predetermined temperature, the thermostat valve (3) is closed. 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 that order. During engine operation, when the temperature of the engine cooling water (9) in the water jacket (2) is higher than a predetermined temperature, the thermostat valve (3) opens. Most of the engine cooling water (9) in the water jacket (2) returns to the water jacket (2) via the valve housing case (4), main water passage (5), radiator (7), and water pump (8) in that order, while a portion 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), bypass water passage (6), and water pump (8) in that order. That is, as shown in FIG. 1, this engine is configured such that, during engine operation, a predetermined amount of engine cooling water (9) in the water jacket (2) is pumped by the pumping force of the water pump (8) to bypass the radiator (7) and return to the water jacket (2) via the valve housing case (4), the bypass water passage (6), and the water pump (8) in that order.

[0019] As shown in FIG. 1, this engine is provided with an air bleed passage (10) that is led out horizontally or upwardly from an upper portion of the impeller chamber (8a) of the water pump (8) and leads to the bypass water passage (6), and an air passage (3a) that allows air to pass from the upstream side of the thermostat valve (3) to the downstream side of the valve. When engine cooling water (9) is supplied from the water inlet (7a) of the radiator (7) while the engine is stopped, air (11) that tends to accumulate in the upper part of the impeller chamber (8a) of the water pump (8) is pushed from the upper part of the impeller chamber (8a) through the air bleed passage (10) and into the bypass water passage (6) as the water level in the cooling water circulation path (1) rises, and is also pushed out of the water inlet (7a) of the radiator (7) via the air passage (3a) and the main water passage (5) in that order.

[0020] In this engine, when the engine cooling water (9) is being supplied, the water level in the cooling water circulation path (1) rises, and the air (11) that tends to accumulate in the upper part of the impeller chamber (8a) of the water pump (8) is pushed out through the water inlet (7a) of the radiator (7). As a result, the air (11) is less likely to remain in the engine cooling water circulation path (1). Therefore, a decrease in cooling performance due to the circulation of the air (11) in the cooling water circulation path (1) during engine operation is less likely to occur, and the cooling performance of the engine is improved. In addition, in this engine, since the air (11) is unlikely to circulate in the cooling water circulation path (1) during engine operation, the cooling water circulation path (1) is unlikely to be damaged by cavitation.

[0021] As shown in FIG. 1, in this embodiment, the air vent passage (10) is formed by a drilled hole leading horizontally from the impeller chamber (8a) to the bypass water passage (6), and the air passage (3a) is formed in the thermostat valve (3). However, the present invention is not limited to this, and the air vent passage (10) may be led obliquely upward or vertically upward from the impeller chamber (8a), and the air passage (3a) may be provided in the valve housing case (4). The pump housing (8b) of the water pump (8), the terminal end of the channel wall (6a) of the bypass channel (6), and the passage wall (10a) of the air vent passage (10) disposed between them are integrally molded from a continuous metal material, and a drilled air vent passage (10) is formed in the passage wall (10a) of the air vent passage (10).

[0022] As shown in FIG. 1, the engine is provided with a reserve tank (12) connected to a water supply port (7a) of the radiator (7). In this engine, air (11) is less likely to remain in the cooling water circulation path (1), so that the amount of engine cooling water (9) in the reserve tank (12) that is exchanged with air (11) is reduced, and the frequency of refilling the reserve tank (12) with engine cooling water (9) can be reduced.

[0023] As shown in FIG. 1, the radiator (7) includes an upper tank (7b), a lower tank (7c), and a heat dissipation pipe (7d) arranged vertically and side-by-side between them. The upper tank (7b) is connected to the valve housing case (4) via a main water passage (5), and the lower tank (7c) is connected to the water pump (8) by a return water passage (72). The water supply port (7a) is provided in the upper tank (7b) and is covered with a radiator cap (7e).

[0024] As shown in FIG. 1, a valve mechanism (7f) is provided in the radiator cap (7e). When the engine is in operation, the volume of the engine cooling water (9) in the cooling water circulation path (1) expands due to a rise in temperature, and the internal pressure of the cooling water circulation path (1) increases. This causes a main pressure valve of the valve mechanism (7f) to open, causing some of the engine cooling water (9) in the cooling water circulation path (1) to overflow and accumulate in the reserve tank (12). After the engine is stopped, when the internal pressure of the cooling water circulation path (1) decreases due to a drop in temperature, the negative pressure valve of the valve mechanism (7f) opens, and some 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 Figures 3(A) and 3(B), the water jacket (2) includes a cylinder jacket (2a) surrounding the cylinder (16) and a head jacket (2b) in the cylinder head (17). As shown in Figure 3(A), the cylinder jacket (2a) includes a jacket inlet (2c) at its front end. As shown in Figure 3(B), the head jacket (2b) includes a jacket outlet (2d) at its front end. Between the cylinder jacket (2a) and the head jacket (2b), there are provided a plurality of water floating ports (18) that open around the periphery of each cylinder (16). Through the plurality of water floating 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 jacket portion (2ba) that faces a rear-end water floating port (18a) in a rear-end head portion (17a) of the cylinder head (17). As shown in FIG. 2, this engine is equipped with 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), and the cooler water supply pipe (20) is led out from the rear end jacket portion (2ba).

[0026] In this engine, the suction force of the water pump (8) is applied to the rear-end jacket portion (2ba) via the cooler drain pipe (21), the oil cooler (19), and the cooler supply water pipe (20), in that order, so that a large amount of engine cooling water (9) is sucked up from the rear-end water floating port (18a) to the rear-end jacket portion (2ba), improving the cooling performance of the rear-end head portion (17a), where the engine cooling water (9) would normally have difficulty floating up. In addition, in this engine, since a large amount of engine cooling water (9) floats from the rear end water floating port (18a) to the rear end jacket portion (2ba), there is no need to narrow the passage cross-sectional area of ​​the other water floating ports (18) for this purpose, and the passage resistance of the cooling water circulation path (1) can be reduced, thereby improving the cooling performance of the engine.

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

[0028] As shown in FIG. 3(B), 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, and the cooler supply water pipe (20) is led out from the intake end side portion (2bc) of the rear end jacket portion (2ba). In this engine, engine cooling water (9) at a relatively low temperature in the intake end portion (2bc) of the rear end jacket portion (2ba) is supplied to the oil cooler (19) through the cooler water supply pipe (20), thereby improving the cooling performance of the oil cooler (19).

[0029] As shown in FIG. 3(B), the head jacket (2b) includes, among the multiple inter-bore upper water passages (23) located between the cylinder bores, a bore-near rear upper water passage (23a) located toward the rear end of the cylinder head (17), among the multiple water floating ports (18), a rear-near water floating port (18b) that supplies engine cooling water (9) to the bore-near rear upper water passage (23a), a rear-near jacket portion (2bd) facing the rear-near water floating port (18b), and a partition wall (24). The rear jacket portion (2bd) is disposed in front of the rear jacket portion (2ba), and the partition wall (24) is disposed between the rear jacket portion (2bd) and the rear jacket portion (2ba). In this engine, the engine cooling water (9) that floats up from the water floating port (18b) near the rear end to the jacket portion (2bd) near the rear end is blocked by the partition wall (24) and is supplied to the bore-to-bore upper water passage (23a) near the rear end without being sucked out into the cooler supply water pipe (20) extending from the rear end jacket portion (2ba), thereby improving the cooling performance of the head portion (17b) near the rear end of the cylinder head (17). As shown in FIG. 3(B), the rear end inter-bore upper water passage (23a) is located between the rearmost cylinder (16) and the cylinder (16) located immediately before it.

[0030] As shown in FIG. 3(C), in this engine, a 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, heat from the head bottom wall (17c) is dissipated to the lower peripheral wall (22b) of the intake port (22) through the partition wall (24), thereby improving the cooling performance of the head bottom wall (17c). In this engine, the partition wall (24) increases the rigidity of the head bottom wall (17c).

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

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

[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, heat from the water passage bottom wall (23b) is dissipated to the peripheral wall (22c) of the intake port (22) through the reinforcing wall (29), thereby improving the cooling performance of the water passage bottom wall (23b). In addition, in this engine, the reinforcing wall (29) connected to the peripheral wall (22c) of the intake port (22) increases the rigidity of the water passage bottom wall (23b).

[0034] As shown in FIGS. 4(A) and 4(C), the reinforcing rib 30 is disposed on the water channel bottom wall portion 23c on the exhaust end side of the water channel bottom wall 23b. In this engine, heat from 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) passing in large quantities above the reinforcing rib (30), thereby improving the cooling performance of the water passage bottom wall portion (23c) on the exhaust end side.

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

[0036] As shown in FIG. 4(A), this engine is provided with a pair of water floatation holes (31)(31) on both lateral sides of the bottom wall (23b) of the inter-bore upper water passage (23) for floating the engine cooling water (9) from the cylinder jacket (2a) to the head jacket (2b). Of the pair of water floatation holes (31)(31), the water floatation hole (31) on the exhaust end side is designated as the exhaust end side water floatation hole (31a) and the water floatation hole (31) on the intake end side is designated as the exhaust end side water floatation hole (31b). As shown in Figures 4(A) and (C), the exhaust end side water floating hole (31a) is formed in the reinforcing rib (30), and as shown in Figures 4(A) and (B), the intake end side water floating hole (31b) is formed in the reinforcing wall (29), and as shown in Figure 4(B), the water floating hole outlet (31ba) of the intake end side water floating hole (31b) is directed toward the exhaust port surrounding wall (32b). As shown in FIG. 4(B), in this engine, 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), thereby improving the cooling performance of the exhaust port peripheral wall (32b).

[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, and 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 via 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 a first transverse wall (33b) immediately below it, and a second transverse water passage (33e) provided between the first transverse wall (33b) and a second transverse wall (33d) immediately below it. The intake end side wall portion (33ba) of the first transverse wall (33b) is inclined downward toward the jacket portion (2aa) on the intake end side, so that the inlet lower portion (33ca) of the first transverse water passage (33c) is inclined downward toward the jacket portion (2aa) on the intake end side, and the inlet upper portion (33ea) of the second transverse water passage (33e) is inclined 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 of the front surface of the front-end cylinder (16), and the passage cross-sectional area of ​​the jacket portion (2aa) on the intake end side is larger than the passage cross-sectional area of ​​the jacket portion (2ab) on the exhaust side, and as shown in FIG. 3(B), the jacket outlet (2d) on the front end side of the head jacket (2b) is positioned biased toward the exhaust end side, so that 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 via the inter-bore water passage (33).

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

[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 a third transverse wall (33f) immediately below the second transverse wall (33d). The intake end side wall portion (33da) of the second transverse wall (33d) is inclined downward toward the intake side jacket portion (2aa), so that the inlet lower portion (33eb) of the second transverse water passage (33e) is inclined downward toward the intake end side jacket portion (2aa) and the inlet upper portion (33ga) of the third transverse water passage (33g) is inclined downward toward the intake end side jacket portion (2aa). In this engine, low-temperature engine cooling water (9) located near the lower part of the jacket portion (2aa) on the intake end side is introduced upward along the slope of the lower inlet (33eb) of the second transverse water passage (33e) and the upper inlet (33ga) of the third transverse water passage (33g), thereby improving the cooling performance between the cylinder bores.

[0041] As shown in FIG. 4(A), in this engine, the exhaust end side water floating hole (31a) is formed so as to have a larger minimum passage cross-sectional area than the intake end side water floating hole (31b). In this engine, the flow of 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, thereby improving the cooling performance between the cylinder bores. The inter-bore water passage 33 includes a fourth transverse water passage 33k provided between the third transverse wall 33f and a fourth transverse wall 33h immediately below the third transverse wall 33f. 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) that supplies 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) that supplies 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) is provided with an oil cooler oil inlet (40), an oil cooler oil supply passage (40a) leading out from the oil cooler oil inlet (40), an oil cooler oil drain port (41), and an oil cooler oil drain passage (41a) leading 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), which have a height difference, the higher one is referred to as the cooler high-altitude port (42) and the lower one is referred to as the cooler low-altitude port (43). Of the oil cooler oil supply passage (40a) and the oil cooler drain passage (41a), the one leading out from the cooler low-altitude port (43) is referred to as the cooler low-altitude port oil passage (43a), and the cooler low-altitude port oil passage (43a) is led out upward to a height equal to or higher than the height of the lower edge (42a) of the cooler high-altitude port (42). A height equal to or higher than the height of the lower edge (42a) of the cooler high-altitude opening (42) means a height equal to or higher than the height of the lower edge (42a) of the cooler high-altitude opening (42).

[0044] In this engine, while the engine is stopped, 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-altitude opening (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, thereby preventing seizure thereof.

[0045] As shown in FIG. 6(B), in this engine, of the oil cooler supply passage (40a) and the oil cooler drain oil passage (41a), the one leading out from the cooler high port (42) is referred to as the cooler high port oil passage (42c), and when viewed in a direction parallel to the lateral direction, the cooler high port oil passage (42c) is led out downward from the cooler high port (42). When the engine is stopped, the engine oil (37) in the oil cooler (19) flows down from the cooler high port (42) through the cooler high port oil passage (42c), the filter low port oil passage (48a), the oil filter (44), and the base oil supply passage (38) in that order toward the oil pan (34), so that it remains only up to the height of the lower edge (42a) of the cooler high port (42).

[0046] The cooler high-altitude port oil passage (42c) shown in Figure 6 (B) may, when viewed in a direction parallel to the lateral direction, lead out upward from the cooler high-altitude port (42) and may also lead out upward to a height equal to or higher than the height of the cooler low-altitude port oil passage (43a) and the lower edge (42a) of the cooler high-altitude port (42). In this case, while the engine is stopped, the engine oil (37) in the oil cooler (19) can remain at the same height as the lower edge (42a) of the cooler high-altitude port (42) or up to the height of the lower edge of the upward lead-out end of the cooler low-altitude port oil passage (43a), which exceeds that height.

[0047] As shown in Figures 6(B) and (C), the cooler high-altitude port (42) is provided within a pipe base end (42ba) of a horizontal pipe (42b) oriented laterally, the pipe base end (42ba) being inserted into the auxiliary equipment mounting base (36). As shown in FIG. 6(B), when viewed in a direction parallel to the horizontal direction, the cooler low-level inlet oil passage (43a) is led upward from the cooler low-level inlet (43) and then led downward to the oil passage inlet (39a) of the crankshaft oil supply passage (39).

[0048] As shown in FIG. 6(B), the oil cooler oil inlet (40) is a cooler high-altitude port (42), the oil cooler oil drain port (41) is a cooler low-altitude port (43), and the oil cooler oil drain passage (41a) is a cooler low-altitude 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 in specific gravity due to cooling by the oil cooler (19), thereby reducing the pumping load on the oil pump (35).

[0049] As shown in FIGS. 6(C) to 6(F), the oil cooler (19) is configured by alternately stacking oil permeable layers (19b) that allow the engine oil (37) to pass through and water permeable layers (19c) that allow the engine cooling water (9) to pass through. As shown in FIG. 6(E), an oil partition wall (19ba) is provided in the oil permeable layer (19b), and as shown in FIG. 6(F), a water partition wall (19ca) is provided in the water permeable layer (19c). In the oil passage layer (19b), the engine oil (37) introduced from the upper rear oil cooler oil inlet (40) is reversed downward and rearward in front of the oil partition wall (19ba) and discharged from the lower rear oil cooler oil outlet (41). In the water passage layer (19c), the engine cooling water (9) introduced from the front lower oil cooler water inlet (70) is reversed upward and forward behind the water partition wall (19ca) and discharged from the front upper oil cooler drain outlet (71).

[0050] As shown in FIG. 5, this engine is provided 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 Figures 6(B) and 6(C), the accessory mounting base (36) is provided with an oil filter inlet (45), an oil filter supply passage (45a) leading out from the oil filter inlet (45), an oil filter drain port (46), and an oil filter drain passage (46a) leading out from the oil filter drain port (46). Of the oil filter inlet (45) and the oil filter drain outlet (46), which have a height difference, the higher one is designated the filter high-level outlet (47) and the lower one is designated the filter low-level outlet (48). Of the oil filter inlet (45a) and the oil filter drain outlet (46a), the one leading out from the filter low-level outlet (48) is designated the filter low-level outlet oil passage (48a), and the filter low-level outlet oil passage (48a) is led upward to a height equal to or higher than the height of the lower edge (47a) of the filter high-level outlet (47). The height equal to or higher than the height of the lower edge (47a) of the high filter opening (47) means a height equal to or higher than the height of the lower edge (47a) of the high filter opening (47).

[0051] As shown in FIG. 6(C), in this engine, of the oil filter supply passage (45a) and the oil filter drain passage (46a), the one leading out from the filter high-altitude opening (47) is designated as the filter high-altitude opening oil passage (47b), and the filter high-altitude opening oil passage (47b) is led out horizontally from the filter high-altitude opening (47). When the engine is stopped, the engine oil (37) in the oil filter (44) flows down from the filter high-altitude opening (47) through the filter high-altitude opening oil passage (47b) and the base oil supply passage (38) in that order toward the oil pan (34), remaining only up to the height of the lower edge (47a) of the filter high-altitude opening (47).

[0052] The filter high-altitude opening oil passage (47b) may be led out upward from the filter high-altitude opening (47) when viewed in a direction parallel to the lateral direction. In this case, while the engine is stopped, the engine oil (37) in the oil filter (44) can be left at the same height as the lower edge (47a) of the filter high-altitude opening (47) or up to the height of the lower edge of the upward leading-out end of the filter high-altitude opening oil passage (47b), which exceeds that height.

[0053] As shown in FIG. 6(C), the filter high port (47) is provided at an oil passage outlet (47c) of a horizontal filter high port oil passage (47b) oriented in the lateral direction of the accessory mounting base (36). As shown in FIG. 6(C), the filter high-placement oil passage (47b) is connected to the oil passage outlet (38a) of the base oil supply passage (38). As shown in FIG. 6(B), the filter low port oil passage (48a) is led upward from the filter low port (48) and is then connected to the upward cooler high port oil passage (42c).

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

[0055] As shown in FIG. 6(B), the oil filter inlet (45) is a filter high-level inlet (47), the oil filter drain outlet (46) is a filter low-level inlet (48), and the oil filter drain passage (46a) is a filter low-level inlet oil passage (48a). In this engine, while the engine is running, the engine oil (37) passing through the oil filter (44) by the pumping force of the oil pump (35) moves downward within the oil filter (44) by its own weight, thereby reducing the pumping load on the oil pump (35).

[0056] A modification of the accessory mounting base 36 shown in FIGS. 7(A) and 7(B) is as follows. The oil cooler supply passage (40a) and the oil cooler drain passage (41a) of the accessory mounting base (36) are both led upward to a height equal to or higher than the height of the inner uppermost portion (19a) of the oil cooler (19).

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

[0058] In this engine, while the engine is stopped, the engine oil (37) remains in the oil cooler (19) filling 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) through the crankshaft oil supply passage (39) in a short time, thereby preventing seizure thereof.

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

[0060] In this engine, while the engine is stopped, the engine oil (37) remains in the oil filter (44) and fills 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) through the crankshaft oil supply passage (39) in a short time, thereby preventing the bearing portion (13a) from seizing.

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

[0062] As shown in FIG. 5, in this engine, an accessory mounting base (36) is attached to the rear of the intake end side of the cylinder block (27). As shown in FIG. 9, the engine is provided with an oil branch pipe (50) extending from the rear side of the accessory mounting base (36), a rear-end-wall crossing oil passage (27b) that crosses the rear-end wall (27a) of the cylinder block (27), and a turbocharger oil supply pipe (51) that supplies engine oil (37) to the bearing portion (49a) of the turbocharger (49). The engine oil (37) of the accessory mounting base (36) is supplied to the bearing portion (49a) of the turbocharger (49) via the oil branch pipe (50), the rear-end-wall crossing oil passage (27b), and the turbocharger oil supply pipe (51) in this order.

[0063] In this engine, the engine oil (37) is supplied to the bearing portion (49a) of the turbocharger (49) via the shortest route from the accessory mounting base (36). Therefore, when the engine is started, the engine oil (37) is supplied to the bearing portion (49a) of the turbocharger (49) in a short time, thereby preventing the bearing portion (49a) from seizing. In addition, in this engine, during a cold start of the engine when the viscosity of the engine oil (37) becomes high, the engine oil (37) passing through the rear end wall crossing oil passage (27b) that crosses the rear end wall (27a) of the cylinder block (27) immediately after the start is warmed by the combustion heat of the engine and becomes low in viscosity. As a result, the engine oil (37) is supplied to the bearing portion (49a) of the turbocharger (49) without delay. Therefore, seizure of the bearing portion (49a) of the turbocharger (49) is prevented even during a cold start.

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

[0065] As shown in FIG. 6(B), the engine oil (37) branches off from an oil cooler drain passage (41a) of the accessory mounting base (36) to an oil branch pipe (50). In this engine, the engine oil (37) cooled by the oil cooler (19) is supplied to the bearing portion (49a) of the turbocharger (49). This prevents the bearing portion (49a) of the turbocharger (49) from seizing even during high engine speeds when the turbocharger (49) is rotating at a high speed.

[0066] The structure of the modified oil branch pipe (50) shown in FIG. 7(C) is as follows. A check valve (52) shown in FIG. 7(D) is attached to the oil branch pipe (50) shown in FIG. 7(C) to prevent the engine oil (37) from flowing back from the oil branch pipe (50) to the accessory mounting base (36). In this engine, while the engine is stopped, the engine oil (37) in the oil branch pipe (50), the rear end wall crossing oil passage (27b), and the turbocharger oil supply pipe (51) shown in FIG. 9 does not drop down to the accessory mounting base (36) side. Therefore, when the engine is restarted, the engine oil (37) is supplied to the bearing portion (49a) of the turbocharger (49) in a short time, and seizure of the bearing portion (49a) of the turbocharger (49) is prevented. The oil branch pipe (50) shown in FIG. 9 is led out from an oil filter oil drain port (46) located upstream of the oil cooler (19) in the flow path.

[0067] The modified example of the oil branch pipe (50) shown in FIG. 7(C) may be combined with the basic example of the accessory mounting base (36) shown in FIG. 6(B) or with the modified example of the accessory mounting base (36) shown in FIG. 7(A). [Explanation of symbols]

[0068] (13)...crankshaft, (13a)...bearing portion, (19)...oil cooler, (19a)...top part inside cooler, (34)...oil pan, (35)...oil pump, (36)...auxiliary equipment mounting base, (37)...engine oil, (38)...base oil supply passage, (39)...crankshaft oil supply passage, (40)...oil cooler oil supply port, (40a)...oil cooler oil supply passage, (41)...oil cooler oil drain port, (41a)...oil cooler oil drain passage, (42) ...Cooler high inlet, (42a)...lower edge, (43)...cooler low inlet, (43a)...cooler low inlet oil passage, (44)...oil filter, (44a)...top of filter, (45)...oil filter inlet, (45a)...oil filter inlet passage, (46)...oil filter drain outlet, (46a)...oil filter drain passage, (47)...filter high inlet, (47a)...lower edge, (48)...filter low inlet, (48a)...filter low inlet oil passage.

Claims

1. An engine including an oil pan (34), an oil pump (35), an accessory mounting base (36) having an oil cooler (19) attached thereto, a base oil supply passage (38) that supplies 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) that supplies the engine oil (37) cooled by the oil cooler (19) from the accessory mounting base (36) to a bearing portion (13a) of a crankshaft (13), The accessory mounting base (36) includes an oil cooler oil supply port (40), an oil cooler oil supply passage (40a) extending from the oil cooler oil supply port (40), an oil cooler oil drain port (41), and an oil cooler oil drain passage (41a) extending from the oil cooler oil drain port (41); An engine characterized in that, of an oil cooler oil supply port (40) and an oil cooler oil drain port (41), which have a height difference, the higher one is designated as a cooler high-altitude port (42) and the lower one is designated as a cooler low-altitude port (43), and, of the oil cooler oil supply passage (40a) and the oil cooler drain passage (41a), the one leading out from the cooler low-altitude port (43) is designated as a cooler low-altitude port oil passage (43a), and the cooler low-altitude port oil passage (43a) is led out upward to a height equal to or higher than the height of a lower edge (42a) of the cooler high-altitude port (42).

2. 2. The engine according to claim 1, As shown in FIG. 6(B), this engine is characterized in that the oil cooler oil supply port (40) is a cooler high-altitude port (42), the oil cooler oil drain port (41) is a cooler low-altitude port (43), and the oil cooler drain oil passage (41a) is a cooler low-altitude port oil passage (43a).

3. In the engine according to claim 1 or 2, The oil filter (44) is attached to the accessory mounting base (36), and engine oil (37) supplied to the accessory mounting base (36) is purified by the oil filter (44) and supplied to the oil cooler (19); The accessory mounting base (36) includes an oil filter inlet (45), an oil filter supply passage (45a) extending from the oil filter inlet (45), an oil filter drain port (46), and an oil filter drain passage (46a) extending from the oil filter drain port (46); An engine characterized in that, of an oil filter inlet (45) and an oil filter drain outlet (46), which have a height difference, the higher one is designated as a filter high-level outlet (47) and the lower one is designated as a filter low-level outlet (48), and, of the oil filter inlet (45a) and the oil filter drain outlet (46a), the one leading out from the filter low-level outlet (48) is designated as a filter low-level outlet oil passage (48a), and the filter low-level outlet oil passage (48a) is led out upward to a height equal to or higher than the height of a lower edge (47a) of the filter high-level outlet (47).

4. 4. The engine according to claim 3, As shown in FIG. 6(B), this engine is characterized in that the oil filter inlet (45) is a filter high-level inlet (47), the oil filter drain outlet (46) is a filter low-level inlet (48), and the oil filter drain passage (46a) is a filter low-level inlet oil passage (48a).

5. An engine including an oil pan (34), an oil pump (35), an accessory mounting base (36) having an oil cooler (19) attached thereto, a base oil supply passage (38) that supplies 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) that supplies the engine oil (37) cooled by the oil cooler (19) from the accessory mounting base (36) to a bearing portion (13a) of a crankshaft (13), The accessory mounting base (36) includes an oil cooler oil supply port (40), an oil cooler oil supply passage (40a) extending from the oil cooler oil supply port (40), an oil cooler oil drain port (41), and an oil cooler oil drain passage (41a) extending from the oil cooler oil drain port (41); The engine is characterized in that an oil cooler supply passage (40a) and an oil cooler drain passage (41a) are both led upward to a height equal to or higher than the height of an inner top portion (19a) of the oil cooler (19).

6. 6. The engine according to claim 5, The oil filter (44) is attached to the accessory mounting base (36), and engine oil (37) supplied to the accessory mounting base (36) is purified by the oil filter (44) and supplied to the oil cooler (19); The accessory mounting base (36) includes an oil filter inlet (45), an oil filter supply passage (45a) extending from the oil filter inlet (45), an oil filter drain port (46), and an oil filter drain passage (46a) extending from the oil filter drain port (46); The engine is characterized in that an oil filter supply passage (45a) and an oil filter drain passage (46a) are both led upward to a height equal to or higher than the height of an inner uppermost portion (44a) of the oil filter (44).

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