engine

Abstract

To provide an engine that enables simplification of a configuration by consolidating branches of a coolant into one region.SOLUTION: In an engine E, an internal passage 32 in which a coolant W circulates is formed inside an engine body EB. The engine includes a connecting tool 46 that is fitted to an inlet 36 of the internal passage 32 and to which an external coolant passage 42 is connected. The connecting tool 46 includes: an outlet side coolant introduction port 48 to which the coolant W derived from an outlet 38 of the internal passage 32 flows in; a first branch port 64 for deriving the coolant W to the inlet 36 of a circulation passage 30; and a second branch port 52 for deriving the coolant W to a radiator Ra.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a liquid-cooled engine cooled by a coolant.

Background Art

[0002] For example, in an engine used as a drive source of a vehicle, there is a liquid-cooled engine cooled by a coolant such as water (for example, Patent Document 1). In the liquid-cooled engine, the coolant circulates, and the coolant having a temperature higher than a specified value is supplied to a radiator for heat dissipation, and the coolant having a temperature lower than the specified value is supplied to the coolant inlet of the engine.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a branch between a passage leading to such a radiator and a passage leading to the coolant inlet of the engine is provided at the coolant outlet of the engine, a branch between the passage from the coolant outlet and the passage of the coolant after heat dissipation by the radiator is also required at the coolant inlet.

[0005] The disclosure of the present application provides an engine that aggregates the branches of the coolant in one place to simplify the configuration.

Means for Solving the Problems

[0006] The engine of the present disclosure is an engine in which a circulation passage through which a coolant circulates is formed inside the engine body, and includes a connector attached to an inlet of the circulation passage to which an external coolant passage is connected. The connector has an outlet-side coolant inlet into which the coolant derived from the outlet of the circulation passage flows, a first branch port that leads the coolant to the inlet of the circulation passage, and a second branch port that leads the coolant to a radiator.

Advantages of the Invention

[0007] According to the engine of the present disclosure, the branching of the coolant is aggregated in the connector on the inlet side. As a result, the configuration is simplified compared to providing the branches on the inlet side and the outlet side separately in the connectors on the inlet side and the outlet side, respectively.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0009] Hereinafter, preferred embodiments of the present disclosure will be described with reference to FIGS. 1 to 5. In FIG. 1, an engine E of the present embodiment is a reciprocating engine, and is used, for example, in an airplane in which a propeller is disposed at the tip of a fuselage. In this case, the engine E is housed in the fuselage, and engine power is transmitted to the propeller. The use of the engine E is not limited to this, and it is applicable, for example, as a drive source for a ship, and is also applicable as a drive source for vehicles such as motorcycles and four-wheeled vehicles.

[0010] In the following description, the "width direction WD" refers to the direction in which the crankshaft 2 of the engine E extends. In the width direction WD, the direction toward the center in the width direction is referred to as the "inner side in the width direction", and the direction away from the center in the width direction is referred to as the "outer side in the width direction". The direction in which the piston 3 of the engine E reciprocates is referred to as the "piston reciprocating direction". The direction orthogonal to both the "width direction WD" and the "piston reciprocating direction" is referred to as the "orthogonal direction PD". In the present embodiment, the engine E is mounted in a state where the piston reciprocating direction faces the "vertical direction VD", that is, the "up and down direction VD", and the width direction WD faces the horizontal direction.

[0011] The engine E of the present embodiment is a six-cylinder engine in which six cylinders (cylinders 6) are arranged in the direction in which the crankshaft 2 extends. However, the number of cylinders is not limited to this, and for example, it may be a four-cylinder engine. Further, the engine E of the present embodiment is a gasoline engine, but the fuel is not limited to gasoline.

[0012] The engine E includes a crankcase 4 that supports the crankshaft 2, a cylinder 6 that protrudes from the crankcase 4 in the reciprocating direction of the piston 3, and a cylinder head 8 that is connected to the protruding end of the cylinder 6. The crankshaft 2 converts the reciprocating motion of the piston 3 into a rotational motion. In the following description, in the vertical direction VD (the reciprocating motion direction of the piston), the direction in which the cylinder 6 protrudes from the crankcase 4 is referred to as "upward", and the opposite side is referred to as "downward".

[0013] The crankcase 4 is divided into two parts, an upper and a lower part, and has a crankcase lower 4a and a crankcase upper 4b. In the present embodiment, the crankcase upper 4b and the cylinder 6 are integrally formed by molding. However, the crankcase upper 4b and the cylinder 6 may be separate. In the following description, the integrated structure of the crankcase upper 4b and the cylinder 6 is referred to as a cylinder block 10.

[0014] The engine E further has a head cover 12 connected to the upper end of the cylinder head 8 and an oil pan 14 connected to the lower end of the crankcase 4. The cylinder head 8 and the head cover 12 form a cam chamber. Oil, which is a kind of engine lubricant, is stored in the oil pan 14. The crankcase 4, the cylinders 6, the cylinder head 8, the head cover 12, and the oil pan 14 constitute the engine body EB.

[0015] An intake port 16 opens on the surface of one end side (the right side in FIG. 1) in the orthogonal direction PD in the cylinder head 8, and an exhaust port 18 opens on the surface of the other end side (the left side in FIG. 1) in the orthogonal direction PD. In the following description, the intake port side in the orthogonal direction PD is referred to as the "intake side", and the exhaust port side is referred to as the "exhaust side".

[0016] The intake port 16 and the exhaust port 18 are passages formed inside the cylinder head 8. The upstream end of the intake port 16 opens on one end side of the cylinder head 8 in the orthogonal direction PD, and the downstream end opens into the combustion chamber 20 inside the cylinder 6. The upstream end of the exhaust port 18 opens into the combustion chamber 20 inside the cylinder 6, and the downstream end opens on the other end side of the cylinder head 8 in the orthogonal direction PD. The intake port 16 and the exhaust port 18 are formed for each cylinder. The intake port 16 introduces external air as intake into the combustion chamber 20. The exhaust port 18 leads out exhaust from the combustion chamber 20.

[0017] External air is supplied as intake from the intake port 16 into the fuel chamber 20, and fuel is injected into the fuel chamber 20 from the injector 22, forming a mixture of fuel and air. The mixture in the combustion chamber 20 is ignited by the spark plug 26 and burns. The exhaust gas after combustion is led out of the engine from the exhaust port 18.

[0018] As shown in FIG. 2, an output shaft 25 is provided on one end side in the engine width direction WD. In the present embodiment, the rotational force of the crankshaft 2 is decelerated by the speed reduction mechanism 28 and transmitted to the output shaft 25. An aircraft propeller, vehicle wheels, etc. are connected to the output shaft 25 directly or via a power transmission member. In the following description, among the outer sides in the width direction of the engine E, the side on which the output shaft 25 is disposed is referred to as the output shaft side, and the opposite side is referred to as the anti-output shaft side.

[0019] The engine E of the present disclosure is a liquid-cooled engine, and the cooling part of the engine E is cooled by the coolant circulating through the circulation passage 30. In the present embodiment, water is used as the coolant. However, the coolant is not limited to water. In the following description, "upstream" and "downstream" respectively refer to the "upstream" and "downstream" in the flow direction of the coolant.

[0020] As shown in FIG. 3, the circulation passage 30 of the coolant of the engine E of the present embodiment has an internal passage 32 and an external passage 34. The internal passage 32 is a passage formed inside the engine body EB, introduced into the engine from the inlet portion 36, and led out of the engine through the outlet portion 38. In the present embodiment, the internal passage 32 of the circulation passage 30 is formed inside the cylinder 6 and the cylinder head 8.

[0021] The external passage 34 shown in FIG. 2 is composed of a pipe disposed outside the engine E, the upstream end of which is connected to the outlet portion 38 and the downstream end of which is connected to a connector 46 attached to the inlet portion 36. In the present embodiment, the pipe constituting the external passage 34 is a steel pipe. However, the pipe is not limited to a steel pipe. The upstream end of the external passage 34 is detachably connected to the outlet portion 38 via a connecting fitting 39 by a fastening member 37 such as a bolt.

[0022] In the present embodiment, the inlet portion 36 of the circulation passage 30 is formed on the mounting surface Su facing the orthogonal direction PD in the engine body EB. Specifically, the inlet portion 36 is formed on the intake-side wall surface Su in the orthogonal direction PD of the cylinder block 10. More specifically, the inlet portion 36 is formed at the middle portion in the engine width direction WD on the intake-side wall surface of the cylinder block 10.

[0023] On the other hand, the outlet portion 38 of the circulation passage 30 is formed on the surface facing the width direction WD in the engine body EB. Specifically, the outlet portion 38 is formed at the end portion in the engine width direction WD of the cylinder head 8. More specifically, the outlet portion 38 is provided at the end portion on the output shaft side in the engine width direction WD of the cylinder head 8.

[0024] A thermostat 40 (FIG. 4) is provided on the downstream side of the external passage 34. The thermostat 40 detects the temperature of the coolant circulating in the engine E, returns the coolant to the internal passage 32 from the inlet portion 36 when the coolant is at a low temperature, and sends the coolant to the radiator circulation passage 42 when the temperature of the coolant rises. The coolant radiated by the radiator Ra (FIG. 3) is returned from the radiator circulation passage 42 to the inlet portion 36 and supplied to the internal passage 32. That is, the thermostat 40 adjusts the temperature of the coolant.

[0025] The radiator circulation passage 42 has a primary-side passage 42a leading from the thermostat 40 to the radiator Ra (FIG. 3) and a secondary-side passage 42b leading from the radiator Ra to the inlet portion 36. The radiator circulation passage 42 is composed of, for example, a steel pipe. However, the radiator circulation passage 42 is not limited to a steel pipe.

[0026] A coolant pump 44 is provided in the secondary side passage 42b. The coolant pump 44 is also provided on the mounting surface Su facing the orthogonal direction PD in the engine body EB. Specifically, the coolant pump 44 is provided on the intake side mounting surface Su in the orthogonal direction PD of the engine body EB. The coolant pump 44 pressurizes the coolant in the secondary side passage 42b. That is, the secondary side passage 42b constitutes a coolant passage through which the coolant W pumped by the coolant pump 44 flows. In the present embodiment, the secondary side passage 42b is composed of a steel pipe. However, the secondary side passage 42b is not limited to a steel pipe.

[0027] The coolant pump 44 of the present embodiment is driven by the rotational force of the crankshaft 2. Specifically, the rotational force of the crankshaft 2 is transmitted to the coolant pump 44 via the drive chain 47. However, the power transmission means is not limited to the drive chain 47.

[0028] A connector 46 is attached to the inlet portion 36 of the circulation passage 30. The connector 46 has an opening 69 (FIG. 4) that communicates with the inlet portion 36 of the circulation passage 30 in a state of being attached to the engine body EB.

[0029] In the present embodiment, the connector 46 constitutes an inlet unit UN. The inlet unit UN is detachably attached to the cylinder block 10, and a thermostat 40 is housed inside. There is no need to provide a separate thermostat case, and the number of parts can be reduced. However, the thermostat 40 may be provided in a thermostat case provided separately from the inlet unit UN. The external passage 34 and the primary side passage 42a and the secondary side passage 42b of the radiator circulation passage 42 are connected to the inlet unit UN.

[0030] As shown in FIG. 4, the inlet unit UN has an outlet side coolant inlet 48 to which the external passage 34 is connected. In the present embodiment, the pipe constituting the external passage 34 is inserted into the outlet side coolant inlet 48 via an elastic member such as an O-ring. The coolant W led out from the outlet portion 38 of the circulation passage 30 flows into the outlet side coolant inlet 48.

[0031] The inlet unit UN further has a primary-side passage connection portion 52 (FIG. 2) to which the primary-side passage 42a of the radiator circulation passage 42 is connected, and a coolant passage connection port 53 to which the secondary-side passage 42b of the radiator circulation passage 42 is connected. In the present embodiment, the downstream end of the pipe constituting the secondary-side passage 42b is inserted into the coolant passage connection port 53 via an elastic member such as an O-ring.

[0032] The upstream end of the pipe constituting the passage between the coolant pump 44 and the connector 46 in the secondary-side passage 42b shown in FIG. 2 is inserted into the outlet 44o of the coolant pump 44 via an elastic member such as an O-ring. Further, the downstream end of the pipe constituting the passage between the radiator Ra (FIG. 3) and the coolant pump 44 in the secondary-side passage 42b is inserted into the inlet 44i of the coolant pump 44 via an elastic member such as an O-ring. Similarly, the pipe constituting the primary-side passage 42a is also inserted into the primary-side passage connection portion 52 via an elastic member such as an O-ring.

[0033] As shown in FIG. 3, the thermostat 40 switches whether to lead the coolant W to the radiator Ra according to the temperature of the coolant W led out from the outlet-side coolant inlet 48.

[0034] In other words, the thermostat 40 switches whether to lead the coolant W to the radiator Ra according to the temperature of the coolant W led out from the outlet portion 38 of the circulation passage 30. In the present embodiment, the primary-side passage connection portion 52 constitutes a second branch port for leading the coolant W to the radiator Ra.

[0035] As shown in FIG. 5, the inlet unit UN has a partition wall 55 inside. The internal space of the inlet unit UN is partitioned by the partition wall 55 so that the coolant W1 introduced from the outlet portion 38 through the external passage 34 and the coolant W2 flowing in from the secondary-side passage 42b of the radiator circulation passage 42 do not mix.

[0036] As shown in FIG. 4, a valve 40a of a thermostat 40 is mounted between an external passage 34 and a primary side passage 42a of a radiator circulation passage 42. When the coolant is at a low temperature, the valve 40a is in a closed state, and the coolant W from the external passage 34 flows from a bypass passage connection port 64 through a secondary side passage 42b toward an inlet portion 36 of a circulation passage 30. That is, the bypass passage connection port 64 constitutes a first branch port that guides the coolant W to the inlet 36 of the circulation passage 30. As the temperature of the coolant rises, the valve 40a gradually opens, and the coolant flows into the primary side passage 42a of the radiator circulation passage 42 connected to a primary side passage connection portion 52.

[0037] As shown in FIG. 2, an oil cooler 60 is provided on an attachment surface Su facing an orthogonal direction PD in an engine body EB. Specifically, the oil cooler 60 is provided on an intake side wall surface Su in the orthogonal direction PD of a cylinder block 10. The oil cooler 60 cools the engine lubricating oil by heat exchange. In the present embodiment, the oil cooler 60 cools the engine lubricating oil by heat exchange with the coolant.

[0038] The oil cooler 60 has a coolant inlet 60a into which the coolant W is introduced and a coolant outlet 60b from which the coolant W after heat exchange is led out. In the present embodiment, the coolant W is supplied to the oil cooler 60 from a connector 46 via a bypass passage 62. The bypass passage 62 has a primary side passage 62a whose one end is connected to the coolant inlet 60a of the oil cooler 60 and a secondary side passage 62b whose one end is connected to the coolant outlet 60b of the oil cooler 60.

[0039] The other end of the primary passage 62a of the bypass passage 62 is connected to the connector 46, and the other end of the secondary passage 62b is connected to the cooling pump 44. That is, the connector 46 and the oil cooler 60 are connected via the primary passage 62a of the bypass passage 62, and the oil cooler 60 and the coolant pump 44 are connected via the secondary passage 62b. In the present embodiment, the pipe constituting the bypass passage 62 is made of a rubber tube. However, the pipe constituting the bypass passage 62 is not limited to a rubber tube, and may be, for example, a steel pipe.

[0040] As shown in FIG. 4, the connector 46 has a bypass passage connection port 64 to which the primary passage 62a of the bypass passage 62 is connected. The bypass passage connection port 64 opens on the side of the outlet-side coolant inlet 48 in the internal space of the inlet unit UN partitioned by the partition wall 55. That is, the coolant W1 flowing in from the external passage 34 is supplied to the bypass passage connection port 64.

[0041] Next, with reference to FIG. 3, the flow of the coolant W of the engine E of the present embodiment will be described. When the engine E starts, the coolant pump 44 is activated in conjunction with this. When the coolant pump 44 is activated, the coolant W in the secondary passage 42b of the radiator circulation passage 42 is pressurized and pumped to the connector 46.

[0042] The coolant W that has flowed into the connector 46 from the coolant passage connection port 53 is supplied from the opening 69 of the connector 46 to the internal passage 32 inside the engine body EB via the inlet portion 36 of the circulation passage 30.

[0043] The coolant W that has flowed into the internal passage 32 cools the cooled portion of the engine E as it flows through the internal passage 32, and then flows out from the outlet portion 38 to the external passage 34 outside the engine body EB. The coolant W that has flowed into the external passage 34 flows into the connector 46 from the outlet-side coolant inlet 48.

[0044] The temperature of the coolant W flowing into the connector 46 from the outlet-side coolant inlet 48 is detected by the thermostat 40. When the coolant W is at a low temperature, the coolant W is returned from the bypass passage connection port 64, which is the first branch port, through the bypass passage 62 and the secondary-side passage 42b to the internal passage 32 from the inlet portion 36.

[0045] When the temperature of the coolant W rises, the coolant W is sent from the primary-side passage connection portion 52, which is the second branch port, to the primary-side passage 42a of the radiator circulation passage 42. The coolant W flowing through the primary-side passage 42a of the radiator circulation passage 42 flows into the radiator Ra. The coolant W that has dissipated heat in the radiator Ra is returned from the secondary-side passage 42b of the radiator circulation passage 42 to the coolant pump 44. Thereafter, the same operation is repeated.

[0046] According to the above configuration, the branching of the coolant W is aggregated at the connector 46 on the inlet side shown in FIG. 2. Specifically, the coolant W flowing into the connector 46 from the coolant passage connection port 53 is led to the opening 69, and the coolant W flowing into the connector 46 from the outlet-side coolant inlet 48 is branched to the bypass passage connection port 64 or the primary-side passage connection portion 52. Thereby, the inlet-side connector and the outlet-side connector can be combined into one, and the configuration is simplified.

[0047] In the present embodiment, the thermostat 40 is disposed inside the connector 46. That is, the connector 46 also serves as a thermo case that houses the thermostat 40. According to this configuration, there is no need to provide the thermo case separately, so the number of parts can be reduced.

[0048] In the present embodiment, an inlet portion 36 of the circulation passage 30 is formed on an attachment surface Su facing the orthogonal direction PD in the engine body EB, and an outlet portion 38 of the circulation passage 30 is formed on a surface facing the engine width direction WD. According to this configuration, since the outlet portion 38 of the circulation passage 30 is formed on the surface of the cylinder head 8 facing the engine width direction WD, a non-turbulent flow of the coolant W can be created from one side to the other side in the width direction WD. Thereby, for example, the periphery of the spark plugs 26 arranged in the width direction can be effectively cooled.

[0049] Since the inlet portion 36 of the circulation passage 30 is formed on the intake-side attachment surface Su in the engine body EB, the coolant W before flowing into the internal passage 32 is less likely to be affected by the high temperature on the exhaust side. However, the inlet portion 36 may be provided on the wall surface on the exhaust side. Further, the inlet portion 36 is provided at the central portion in the engine width direction WD on the attachment surface Su facing the orthogonal direction PD. Therefore, the external passage 34 between the inlet portion 36 and the outlet portion 38 at the end surface in the engine width direction WD can be shortened. As a result, it becomes possible to configure the external passage 34 with a steel pipe, and the support of the steel pipe can also be omitted. In particular, in an aircraft engine, a steel pipe is preferable due to its fire resistance and resistance to deformation during altitude increase.

[0050] In the present embodiment, the coolant pump 44 is provided on the same attachment surface Su as the inlet portion 36. According to this configuration, the coolant pump 44 can be arranged close to the inlet-side connector 46, and the secondary-side passage 42b between the coolant pump 44 and the connector 46 can be made compact. As a result, the piping of the coolant passage can be shortened, or the support of the piping can be omitted. Further, it becomes easier to configure the secondary-side passage 42b between the coolant pump 44 and the connector 46 with a steel pipe. Further, since the primary-side passage connection portion 52 to which the primary-side passage 42a of the radiator circulation passage 42 is connected and the coolant passage connection port 53 to which the secondary-side passage 42b is connected are provided on the same plane Su, the installation of the piping entering and leaving the radiator Ra becomes easy.

[0051] In the present embodiment, the oil cooler 60 is provided on the same mounting surface Su as the inlet portion 36. According to this configuration, the oil cooler 60 can be arranged close to the connector 46 on the inlet side, and the bypass passage 62 through which the coolant is returned from the connector 46 through the oil cooler 60 to the coolant pump 44 can be made compact. As a result, the piping of the bypass passage 62 can be shortened, or the support of the piping can be omitted.

[0052] The engine of the present disclosure includes the following aspects 1 to 7. [Aspect 1] An engine in which a circulation passage through which coolant circulates is formed inside the engine body, comprising a connector attached to the inlet of the circulation passage to which an external coolant passage is connected, the connector having an outlet-side coolant inlet into which the coolant led out from the outlet of the circulation passage flows, a first branch port for leading the coolant to the inlet of the circulation passage, and a second branch port for leading the coolant to the radiator. [Aspect 2] In the engine according to Aspect 1, further comprising a thermostat for adjusting the temperature of the coolant led out from the outlet of the circulation passage, the thermostat being configured to be able to switch the opening and closing of the second branch port based on the temperature of the coolant led out from the outlet of the circulation passage, and the thermo case being arranged inside the connector. [Aspect 3] In the engine according to Aspect 1 or 2, the connector has a coolant passage connection port to which the coolant passage is connected. [Aspect 4] In the engine according to any one of Aspects 1 to 3, an inlet of the circulation passage is formed on a mounting surface facing an orthogonal direction that is orthogonal to both the reciprocating direction of the piston and the engine width direction in which the crankshaft extends. [Aspect 5] In the engine according to Aspect 4, a coolant pump for pumping the engine coolant to the coolant passage is provided on the mounting surface. [Aspect 6] In the engine according to Aspect 4 or 5, an engine in which an oil cooler for cooling the lubricating fluid of the engine is provided on the mounting surface. [Aspect 7] In the engine according to Aspect 6, further provided with a bypass passage for returning the coolant from the first branch port to the coolant pump through the oil cooler.

[0053] The present disclosure is not limited to the above forms, and various additions, changes, or deletions are possible without departing from the gist of the present disclosure. For example, the engine E of the above embodiment can also be applied to straddle-type vehicles such as motorcycles, three-wheeled vehicles, and four-wheel buggies (all-terrain vehicles). The engine E may be used for an outboard motor or as a propulsion source for an aircraft. In addition, the engine E may be used as a propulsion source for four-wheel vehicles or small motorboats. The number of cylinders is not limited to six cylinders, and may be less than six cylinders or seven cylinders or more. A supercharger such as a turbocharger or a supercharger may be provided for the engine E. Therefore, such things are also included within the scope of the present disclosure.

Explanation of Reference Numerals

[0054] 30 Circulation passage 32 Internal passage 36 Inlet portion (inlet of the internal passage) 38 Outlet portion (outlet of the internal passage) 40 Thermostat 42b Secondary side passage 44 Coolant pump 46 Connector 48 Outlet side coolant inlet 52 Primary side passage connection portion (second branch port) 53 Coolant passage connection port 60 Oil cooler 62 Bypass passage 64 Bypass passage connection port (first branch port) E Engine EB Engine body Su Mounting surface

Claims

1. An engine having a circulation passage through which a coolant circulates formed inside the engine body, a connector that is attached to an inlet of the circulation passage and connects an external coolant passage; The connector has an outlet side coolant inlet port into which the coolant discharged from the outlet of the circulation passage flows, a first branch port that discharges the coolant to the inlet of the circulation passage, and a second branch port that discharges the coolant to a radiator.

2. 2. The engine according to claim 1, further comprising a thermostat for adjusting a temperature of the coolant discharged from the outlet of the circulation passage, the thermostat is configured to be capable of switching between opening and closing of the second branch port based on a temperature of the coolant discharged from the outlet of the circulation passage, An engine in which the thermostat case is disposed inside the connector.

3. 3. The engine according to claim 1, wherein an inlet of said circulation passage is formed in a mounting surface facing a direction perpendicular to both the reciprocating direction of the pistons and the width direction of the engine in which the crankshaft extends.

4. 4. The engine according to claim 3, further comprising a coolant pump mounted on said mounting surface for pumping engine coolant to said coolant passage.

5. 4. The engine according to claim 3, further comprising an oil cooler mounted on said mounting surface for cooling engine lubricating fluid.

6. 6. The engine according to claim 5, further comprising a bypass passage for returning the coolant from the first branch port to the coolant pump via the oil cooler.

7. 3. The engine according to claim 1, wherein the connector has a coolant passage connection port to which the coolant passage is connected.

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