JP2019011765A - Water-cooled engine - Google Patents

Abstract

To provide a water-cooled engine capable of improving cooling efficiency of engine oil and a cylinder barrel.SOLUTION: A cylinder block 5 provided with a cylinder jacket for passing engine cooling water around the cylinder barrel, the cylinder jacket has a jacket inlet for introducing engine cooling water supplied from a radiator, and a relay waterway 18 is provided between the radiator and the jacket inlet. With the width direction of the engine regarded as the lateral direction, the lateral one side regarded as the intake side and the lateral other side regarded as the exhaust side, the relay waterway 18 is provided on the intake side, the entire amount of engine cooling water from the radiator is supplied to the jacket inlet via the relay waterway 18, and an oil cooler 21 is disposed in the relay waterway 18.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a water-cooled engine, and more particularly to a water-cooled engine that can increase the cooling efficiency of engine oil and cylinder barrels.

  Conventionally, a vertical in-line multi-cylinder engine includes a cylinder jacket that allows engine coolant to pass around a plurality of cylinder barrels. (For example, refer to Patent Document 1).

  This type of engine has an advantage that each cylinder barrel can be strongly cooled with engine cooling water.

  In the thing of patent document 1, the jacket inlet_port | entrance of a cylinder jacket is arrange | positioned just beside the front end cylinder barrel.

JP 2008-95645 A (see FIGS. 1 and 2)

<< Problem >> Cooling efficiency of engine oil and cylinder barrel may be insufficient.
In the engine of Patent Document 1, the difference in distance from the jacket inlet to the front and rear cylinder barrels is large, the front cylinder barrel is overcooled and the rear cylinder barrel is less likely to be cooled, and the temperature distribution among the cylinder barrels is uneven. It is easy to become a state. No cooling of engine oil is disclosed. In general, the engine may have insufficient cooling efficiency of the engine oil and the cylinder barrel.

  The subject of this invention is providing the water cooling engine which can improve the cooling efficiency of engine oil and a cylinder barrel.

Invention specific matters of the invention according to claim 1 are as follows.
As shown in FIG. 1, a cylinder block (5) provided with a cylinder jacket (3) for allowing engine coolant (2) to pass therearound is provided around the cylinder barrel, and the cylinder jacket (3) is supplied from a radiator. A jacket inlet (3a) for introducing engine coolant (2);
As illustrated in FIG. 6, a relay water channel (18) is provided between the radiator and the jacket inlet (3 a), and the engine width direction is the horizontal direction, the horizontal side is the intake side, and the horizontal other side is the exhaust side. The water channel (18) is provided on the intake side,
The entire amount of engine cooling water (2) from the radiator is supplied to the jacket inlet (3a) via the relay water channel (18).
As illustrated in FIG. 6, the water-cooled engine is characterized in that an oil cooler (21) is disposed in the relay water channel (18).

<Effect> Engine oil cooling efficiency can be increased.
As illustrated in FIG. 6, engine oil (4 a) is produced by a large amount of engine cooling water (2) before being introduced into the cylinder jacket (3) in the relay water passage (18) on the intake side that does not receive heat from the exhaust. Is cooled, and the cooling efficiency of the engine oil (4a) is high. Can be increased.
<Effect> Cooling efficiency of the cylinder barrel can be increased.
As illustrated in FIG. 6, on the intake side that does not receive heat from the exhaust, the entire amount of engine coolant (2) supplied from the radiator passes through the relay water channel (18) and then is supplied to the cylinder jacket (3). Thus, the cooling efficiency of the cylinder barrel can be increased.

It is a cross-sectional top view of the cylinder block of the engine which concerns on embodiment of this invention. It is the II-II sectional view taken on the line of FIG. It is the III-III sectional view taken on the line of FIG. It is a front view of the cylinder block of FIG. 5A is a cross-sectional view taken along line VA-VA in FIG. 4, and FIG. 5B is a cross-sectional view taken along line VB-VB in FIG. It is a principal part longitudinal section front view of an engine concerning an embodiment of the present invention. 1 is a side view of an engine according to an embodiment of the present invention. It is a top view of the engine of FIG.

  1 to 8 are views for explaining a water-cooled engine according to an embodiment of the present invention. In this embodiment, a water-cooled common rail in-line four-cylinder diesel engine will be described.

The outline of this engine is as follows.
As shown in FIGS. 6-8, this engine was assembled | attached to the cylinder block (5), the cylinder head (6) assembled | attached to the upper part of the cylinder block (5), and the upper part of the cylinder head (6). As shown in FIG. 7, the cylinder block (5) has a cylinder head cover (7), an oil pan (4) assembled to the lower part of the cylinder block (5), and a crankshaft (not shown). ), The belt transmission mechanism (9) disposed at the front of the cylinder block (5), the flywheel housing (10) disposed at the rear of the cylinder block (5), and the width direction of the engine perpendicular to the front-rear direction as a lateral direction. As shown in FIG. 6, an intake manifold (11) provided on one side of the cylinder head (6) and an exhaust manifold (12) provided on the other side of the cylinder head (6) are provided.
This engine includes a fuel injection device, a vibration isolation device, a water cooling device, a lubrication device, and an oil cooling device.

The fuel injection device is of a common rail type and includes a fuel supply pump (13), a common rail (14) as shown in FIG. 7, and a fuel injector (15) as shown in FIG. Inject fuel.
The vibration isolator includes a rotation balancer (not shown), cancels out secondary vibration of the engine, and reduces engine vibration.

The water cooling device includes a radiator (not shown), a water inlet chamber (16) provided on the intake side of the cylinder block (5) as shown in FIG. 6, and a water inlet chamber (16) as shown in FIG. 16) a water pump (17) provided at the front of the water pump (17), and a relay water channel (18) provided at the lower part of the water inlet chamber (16) after the water pump (17), as shown in FIG. As shown in FIG. 1, a cylinder side water jacket (3) provided in the cylinder block (5) and a head side water jacket (not shown) provided in the cylinder head (6) are provided.
The water cooling device uses the pump pressure of the water pump (17) to dissipate engine cooling water radiated by the radiator into the water inlet chamber (16), the water pump (17), the relay water channel (18), and the cylinder side water jacket (3). Then, circulate the head side water jacket and radiator in this order to cool the engine with water.

  The lubricating device includes an oil pump (not shown) built in the rear part of the cylinder block (5), an oil cooler (21) housed in the relay water channel (18), as shown in FIG. (22) includes an oil filter (23) attached together with an oil cooler (21), and an oil gallery (24) provided in a wall on the intake side of the cylinder block (5). The engine oil (4a) in the oil pan (4) is supplied to an oil pump, an oil cooler (21), an oil filter (23), an oil gallery (24), a bearing (not shown) of the crankshaft shown in FIG. The engine sliding part and the oil pan (4) are circulated in this order to forcibly lubricate the engine sliding part.

  As shown in FIG. 6, the oil cooling device includes an oil delivery passage (25) provided in parallel with the oil gallery (24) in the intake side wall of the cylinder block (5), and a lower portion of the piston (26). An oil jet nozzle (25a) provided in the piston and a cooling channel (26a) provided in the piston (26), and the engine oil that has passed through the oil cooler (21) and the oil filter (23) of the lubrication device in turn. 4a) is partly divided into the oil delivery passage (25) in the accessory mounting base (22), and injected from the oil jet nozzle (25a) into the cooling channel (26a), and the piston (26) is Oil cool.

As shown in FIG. 1, the engine includes a cylinder block (5) provided with a cylinder jacket (3) for allowing engine coolant (2) to pass around a plurality of serial cylinder barrels.
The configuration of the cylinder block (5) is as follows.
A plurality of cylinder barrels include a front end barrel (B1), a rear end barrel (B4), and a front end barrel (B4) between the longitudinal direction of the crankshaft central axis (8b) and the rear side of the flywheel (10a). The intermediate barrel (B2) (B3) located is provided.
The cylinder jacket (3) is divided into a jacket inlet (3a) for introducing engine cooling water (2) supplied from the radiator and an engine cooling water (2) introduced from the jacket inlet (3a) in the front-rear direction. A water channel (3b), a plurality of branch outlets for diverting engine cooling water (2) branched in the front-rear direction toward each cylinder barrel, and each cylinder barrel for engine cooling water (2) introduced from each branch outlet The heat-dissipating water channel (3c) for radiating the heat is provided.

The plurality of diversion outlets include a front diversion outlet (b1) to the front end barrel (B1), a rear diversion outlet (b4) to the rear end barrel (B4), a front end barrel (B1), and a rear end barrel (B4). Intermediate branch outlets (b2) and (b3) are provided to the intermediate barrels (B2) and (B3) located between them.
It is located next to all the intermediate barrels (B2) (B3), and within all the intermediate barrel lateral regions (E23) having the same longitudinal length from the front end to the rearmost end of all the intermediate barrels (B2) (B3). It arrange | positions so that a jacket inlet_port | entrance (3a) may be accommodated.
That is, the jacket inlet (3a) is disposed so as not to protrude forward and backward from the entire intermediate barrel lateral region (E23).

  For this reason, in this embodiment, the engine coolant (2) is introduced into the cylinder jacket (3) from the jacket inlet (3a) in the entire intermediate barrel lateral region (E23), and from the jacket inlet (3a) to each cylinder barrel. The distance difference between the cylinder barrels is less likely to be excessive and insufficient, and the temperature distribution between the cylinder barrels becomes uniform.

As shown in FIG. 1, it is located beside the front end barrel (B1) and is arranged so that the front branch outlet (b1) is placed in the front end barrel lateral region (E1) having the same longitudinal length as the front end barrel (B1). It is located beside the rear end barrel (B4), and is arranged so that the rear branch outlet (b4) fits in the rear end barrel lateral region (E4) of the same longitudinal length as the rear end barrel (B4), and the intermediate barrel (B2 ) (B3) is positioned so that the intermediate diversion outlets (b2) (b3) are placed in the intermediate barrel horizontal region (E2) (E3) which is the same longitudinal length as the intermediate barrels (B2) (B3). ing.
That is, each branch outlet is arranged so as not to protrude forward and backward from the corresponding barrel lateral region.

  For this reason, in this embodiment, the relative position of each branch outlet and each cylinder barrel is unified, and the cooling conditions of each cylinder barrel approach a uniform state.

  As shown in FIG. 1, this engine is a four-cylinder engine, the jacket inlet (3a) is arranged behind the entire intermediate barrel horizontal region (E23), and the front diversion outlet (b1) is the front end barrel horizontal region (E1). ) Is arranged at the rear side, the rear branch outlet (b4) is arranged at the front side of the rear end barrel horizontal region (E4), and the pair of intermediate branch outlets (b2) and (b3) are provided at the pair of intermediate barrel horizontal regions ( E2) It is arranged at the back of each of (E3).

  For this reason, in this embodiment, the shunt distance to the cylinder barrel of the rear two cylinders, which is likely to be hindered by the flywheel (10a), is shortened, and the shunt distance to the cylinder barrel of the front two cylinders, which is easily radiated, is long. Thus, the temperature distribution between the cylinder barrels of the four cylinders approaches uniformly.

As shown in FIG. 1, the cylinder jacket (3) includes a series of partition walls (3d) that partition the diversion water channel (3b) and the radiating water channel (3c).
The partition wall (3d) includes a laterally convex curved portion (C2) (C3) of the pair of intermediate barrels (B2) and (B3) and a laterally concave portion (between these laterally convex curved portions (C2) and (C3)). D23) is bent according to the unevenness, and both ends of the partition wall (3d) and the folded portion of the bending are screw bosses that are screw-fitted with head bolts (3h) for fastening the cylinder head (6) to the cylinder block (5). (3e) is provided.

  For this reason, in this embodiment, the rigidity of the partition wall (3d) is increased by the screw boss (3e), the partition wall (3d) is hard to vibrate, and the combustion sound and piston slap sound released from each cylinder barrel are generated in the partition. Engine noise which is rebounded by the wall (3d) and released to the side of the cylinder block (5) is reduced.

As shown in FIG. 1, the cylinder jacket (3) is provided with a transverse water passage (3f) that allows the engine cooling water (2) to pass between adjacent cylinder barrels, and at the water passage inlet (3g) of the transverse water passage (3f). The screw boss (3e) protrudes from the partition wall (3d).
For this reason, in this embodiment, the engine cooling water (2) that has flowed into the radiating water channel (3c) is guided toward the transverse water channel (3f) by the guide of the screw boss (3e), and the cooling efficiency between the cylinder barrels is increased.

As shown in FIG. 1, the screw boss (3e) protrudes from the partition wall (3d) toward the laterally convex curved portions (C2) and (C3) of the intermediate barrels (B2) and (B3).
For this reason, in this embodiment, the engine cooling water (2) flowing into the facility water channel (3c) is guided by the screw boss (3e) to the laterally convex curved portions (C2) (C3) of the intermediate barrels (B2) (B3). The cooling efficiency of the intermediate barrels (B2) (B3) is increased.

As shown in FIG. 2, the lower opening edge (bu) of each branch outlet is provided at a position higher than the vertical center (BC) of the cylinder barrel that the branch outlet faces.
For this reason, in this embodiment, engine cooling water (2) is introduced into the upper half side of the cylinder barrel from the diversion outlet, and insufficient cooling on the upper half side of the cylinder barrel and overcooling on the lower half side are avoided. The temperature distribution in the vertical direction of each cylinder barrel approaches a uniform state.

As shown in FIG. 2, the lower opening edge (bu) of each diversion outlet is the lowermost end (26c) of the pressure ring (26b) of the piston (26) at the top dead center position in the cylinder barrel facing the diversion outlet. Lower than the lowest end (26d) of the piston (26).
For this reason, in this embodiment, there is insufficient cooling of the upper part of the cylinder barrel that is susceptible to high heat from the pressure ring (26b), and overcooling of the lower part of the cylinder barrel that is difficult to receive heat radiation from the piston (26). The temperature distribution in the vertical direction of each cylinder barrel approaches a uniform state.
There are two pressure rings (26b) at the top and bottom, and the lower end of the lower pressure ring (26b) is the lowermost end (26c).
An oil ring (27) is provided below the lower pressure ring (26b), and the opening lower edge (bu) of each branch outlet is a piston at the top dead center position in the cylinder barrel where the branch outlet faces. It is disposed at a position lower than the lower end of the oil ring (27) of (26).

As shown in FIG. 1, the cylinder block (5) has an oil inlet (25b) for introducing engine oil (4a) supplied from an oil pump and an engine oil (4a) introduced from the oil inlet (25b). An oil delivery passage (25) for diverting in the front-rear direction and a plurality of engine oils (4a) diverted in the front-rear direction in the oil delivery passage (25) to the oil jet nozzles (25a) facing each piston (26) It has a branch oil outlet.
The oil delivery passage (25) is directed in the front-rear direction, and the plurality of branch oil outlets are a front branch oil outlet (h1) and a rear branch oil outlet (respectively located on the front side and the rear side of the oil delivery passage (25)). h4) and intermediate branch oil outlets (h2) and (h3) located between the front branch oil outlet (h1) and the rear branch oil outlet (h4).
As shown in FIG. 1, when viewed in a direction parallel to the cylinder center axis (CC), the oil inlet (25b) is disposed at a position overlapping the all intermediate barrel lateral region (E23).
Specifically, the oil inlet (25b) is disposed in a region directly below the intermediate barrel horizontal region (E23) when viewed in a direction parallel to the cylinder center axis (CC).

  For this reason, in this embodiment, the difference in distance from the oil inlet (25b) to each oil diverter becomes small, the cooling of each piston (26) hardly occurs, and the temperature distribution between a plurality of cylinder barrels is reduced. It approaches a uniform state.

When viewed in a direction parallel to the cylinder center axis (CC), each branch oil outlet is disposed at a position overlapping the corresponding barrel lateral region.
Specifically, each branch oil outlet is arranged at a position directly below the corresponding barrel lateral region.

As shown in FIG. 1, a cylinder block (5) provided with a cylinder jacket (3) for allowing engine coolant (2) to pass therethrough is provided around the cylinder barrel, and the cylinder jacket (3) is an engine supplied from a radiator. A jacket inlet (3a) for introducing the cooling water (2) is provided.
As shown in FIG. 6, a relay water channel (18) is provided between the radiator and the jacket inlet (3 a), the engine width direction is the horizontal direction, the horizontal one side is the intake side, and the horizontal other side is the exhaust side. (18) is provided on the intake side.
The entire amount of engine cooling water (2) from the radiator is supplied to the jacket inlet (3a) via the relay water channel (18).
For this reason, in this embodiment, a large amount of engine cooling water (2) supplied from the radiator is supplied to the cylinder jacket (3) after passing through the relay water channel (18) on the intake side that does not receive heat from the exhaust. The cooling efficiency of the cylinder barrel is increased. Can be increased.

  As shown in FIG. 6, an oil cooler (21) is disposed in the relay water channel (18). For this reason, the engine oil (4a) is cooled by a large amount of engine coolant (2) before being introduced into the cylinder jacket (3) in the relay water passage (18) on the intake side which does not receive heat from the exhaust, and the engine oil (4a) is cooled. The cooling efficiency of the oil (4a) can be increased.

As shown in FIG. 6, the relay water channel (18) is formed by recessing the lateral side surface of the cylinder block (5), and the oil cooler (21) is attached to the accessory mounting base (22). An oil cooler (21) is inserted into the relay water channel (18) covered with the base (22).
For this reason, in this embodiment, the oil cooler (21) is inserted into the relay water channel (18) recessed in the cylinder block (5), and the width of the engine is greatly increased by the arrangement of the oil cooler (21). There is no.

As shown in FIG. 6, an oil filter (23) communicating with the oil cooler (21) is attached to the accessory mounting base (22).
For this reason, if the relay water channel (18) is covered with the auxiliary equipment mounting base (22) to which the oil cooler (21) and the oil filter (23) are attached, the oil cooler (21) and the oil filter are attached to the cylinder block (5). (23) is attached, and the oil cooler (21) and the oil filter (23) can be easily attached.

  As shown in FIG. 1, the oil gallery (24) includes an oil inlet (24a) and an oil outlet (24b) to a journal bearing (not shown) of the crankshaft (not shown) shown in FIG. 5 (A). The oil outlet (24b) is arranged at a position where the journal bearing is located.

  (2) ... Engine cooling water, (3) ... Cylinder jacket, (3a) ... Jacket inlet, (3b) ... Diverted water channel, (3c) ... Radiated water channel, (3d) ... Partition wall, (3e) ... Screw boss, ( 3f) ... Transverse water channel, (3g) ... Water channel inlet, (3h) ... Head bolt, (4a) ... Engine oil, (5) ... Cylinder block, (6) ... Cylinder head, (8b) ... Crankshaft central axis, (10a) ... Flywheel, (B1) ... Front end barrel, (B2) ... Intermediate barrel, (B3) ... Intermediate barrel, (B4) ... Rear end barrel, (BC) ... Vertical center of cylinder barrel, (b1) ... Front branch outlet, (b2) ... Intermediate branch outlet, (b3) ... Intermediate branch outlet, (b4) ... Back branch outlet, (bu) ... Lower opening edge, (CC) ... Cylinder center axis, (E1) ... Front end barrel Horizontal region, (E2) ... Intermediate barrel lateral region, (E3) ... Intermediate barrel lateral region, (E23) ... All intermediate barrel lateral regions, (E4) ... Rear end Lateral region, (C2) ... Lateral convex curve, (C3) ... Lateral convex curve, (D23) ... Lateral recess, (18) ... Relay channel, (20) ... Head jacket, (21) ... Oil cooler , (22) ... Auxiliary equipment mounting base, (23) ... Oil filter, (25) ... Oil delivery passage, (25a) ... Oil jet nozzle, (25b) ... Oil inlet, (h1) ... Pre-divided oil outlet, ( h2) ... intermediate diversion oil outlet, (h3) ... intermediate diversion oil outlet, (h4) ... rear diversion oil outlet, (26) ... piston, (26b) ... pressure ring, (26c) ... bottom end of pressure ring, ( 26d) The lowest end of the piston.

Claims (12)

A cylinder block (5) provided with a cylinder jacket (3) for passing engine cooling water (2) around the cylinder barrel is provided. The cylinder jacket (3) introduces engine cooling water (2) supplied from a radiator. Equipped with a jacket inlet (3a)
A relay water channel (18) is provided between the radiator and the jacket inlet (3a), the engine width direction is the horizontal direction, the horizontal side is the intake side, the horizontal other side is the exhaust side, and the relay water channel (18) is the intake side. Provided in
The entire amount of engine cooling water (2) from the radiator is supplied to the jacket inlet (3a) via the relay water channel (18).
A water-cooled engine, characterized in that an oil cooler (21) is arranged in the relay water channel (18). The vertical in-line multi-cylinder engine according to claim 1,
The relay water channel (18) is formed by recessing the lateral side surface of the cylinder block (5), the oil cooler (21) is attached to the accessory mounting base (22), and the lid is covered by the accessory mounting base (22). A water-cooled engine, wherein an oil cooler (21) is inserted into the relay water channel (18). The vertical in-line multi-cylinder engine according to claim 2,
A water-cooled engine characterized in that an oil filter (23) communicating with an oil cooler (21) is attached to the auxiliary equipment mounting base (22). With multiple in-line cylinder barrels,
A plurality of cylinder barrels include a front end barrel (B1), a rear end barrel (B4), and a front end barrel (B4) between the longitudinal direction of the crankshaft central axis (8b) and the rear side of the flywheel (10a). With intermediate barrels (B2) (B3) located,
The cylinder jacket (3) includes a branch water channel (3b) for diverting engine cooling water (2) introduced from the jacket inlet (3a) in the front-rear direction, and an engine cooling water (2) diverted in the front-rear direction to each cylinder. A plurality of branch outlets for branching toward the barrel, and a facility water channel (3c) for radiating heat from each cylinder barrel to the engine coolant (2) introduced from each branch outlet,
The plurality of diversion outlets include a front diversion outlet (b1) to the front end barrel (B1), a rear diversion outlet (b4) to the rear end barrel (B4), a front end barrel (B1), and a rear end barrel (B4). The intermediate branch outlet (b2) (b3) to the intermediate barrel (B2) (B3) located between
It is located next to all the intermediate barrels (B2) (B3), and within all the intermediate barrel lateral regions (E23) having the same longitudinal length from the front end to the rearmost end of all the intermediate barrels (B2) (B3). A water-cooled engine, characterized in that the jacket inlet (3a) is arranged to be accommodated. The water-cooled engine according to claim 4,
Located at the side of the front end barrel (B1), the front branch outlet (b1) is disposed in the front end barrel horizontal region (E1) having the same longitudinal length as the front end barrel (B1), and the rear end barrel (B4) The rear outlet (b4) is located within the rear barrel side region (E4) of the same length as the rear end barrel (B4), and is located next to the intermediate barrels (B2) (B3). The intermediate branch outlets (b2) and (b3) are located in the middle barrel lateral region (E2) and (E3) that are located and have the same longitudinal length as the middle barrels (B2) and (B3). A water-cooled engine. The water-cooled engine according to claim 5,
In a four-cylinder engine, the jacket inlet (3a) is disposed behind the entire intermediate barrel lateral region (E23), and the front branch outlet (b1) is disposed behind the front barrel lateral region (E1). (b4) is arranged in front of the rear end barrel horizontal region (E4), and the pair of intermediate branch outlets (b2) and (b3) are arranged in the rear of the pair of intermediate barrel horizontal regions (E2) and (E3). A water-cooled engine characterized by that. The water-cooled engine according to any one of claims 4 to 6,
The cylinder jacket (3) includes a series of partition walls (3d) that partition the diversion water channel (3b) and the facility water channel (3c),
The partition wall (3d) includes a laterally convex curved portion (C2) (C3) of the pair of intermediate barrels (B2) and (B3) and a laterally concave portion (between these laterally convex curved portions (C2) and (C3)). D23) is bent according to the unevenness, and both ends of the partition wall (3d) and the folded portion of the bending are screw bosses that are screw-fitted with head bolts (3h) for fastening the cylinder head (6) to the cylinder block (5). (3e) It is provided with the water cooling engine characterized by the above-mentioned. The water-cooled engine according to claim 7,
The cylinder jacket (3) includes a transverse water passage (3f) for allowing the engine coolant (2) to pass between adjacent cylinder barrels, and a partition wall (3d) toward the water passage inlet (3g) of the transverse water passage (3f). The water-cooled engine, wherein the screw boss (3e) is raised. The water-cooled engine according to claim 7 or 8,
The water-cooled engine, wherein the screw boss (3e) is raised from the partition wall (3d) toward the laterally convex curved portion (C2) (C3) of the intermediate barrel (B2) (B3). The water-cooled engine according to any one of claims 1 to 6,
The water-cooled engine, wherein the lower opening edge (bu) of each branch outlet is provided at a position higher than the vertical center (BC) of the cylinder barrel facing the branch outlet. The water-cooled engine according to claim 10,
The lower opening edge (bu) of each branch outlet is lower than the lowermost end (26c) of the pressure ring (26b) of the piston (26) at the top dead center position in the cylinder barrel facing the branch outlet. 26) A water-cooled engine characterized by being provided at a position higher than the lowermost end (26d) of 26). The water-cooled engine according to any one of claims 1 to 11,
With multiple in-line cylinder barrels,
A plurality of cylinder barrels include a front end barrel (B1), a rear end barrel (B4), and a front end barrel (B4) between the longitudinal direction of the crankshaft central axis (8b) and the rear side of the flywheel (10a). With intermediate barrels (B2) (B3) located,
The cylinder block (5) includes an oil inlet (25b) for introducing engine oil (4a) supplied from an oil pump and an oil delivery for diverting the engine oil (4a) introduced from the oil inlet (25b) in the front-rear direction. A plurality of diversion oil outlets for diverting the engine oil (4a) divided in the front-rear direction in the passage (25) and the oil delivery passage (25) to the oil jet nozzle (25a) facing each piston (26);
The oil delivery passage (25) is directed in the front-rear direction, and the plurality of branch oil outlets are a front branch oil outlet (h1) and a rear branch oil outlet (respectively located on the front side and the rear side of the oil delivery passage (25)). h4), and an intermediate branch oil outlet (h2) (h3) located between the front branch oil outlet (h1) and the rear branch oil outlet (h4),
A water-cooled engine characterized in that the oil inlet (25b) is disposed at a position overlapping the all intermediate barrel lateral region (E23) when viewed in a direction parallel to the cylinder center axis (CC).

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