JP6146423B2 - Water-cooled engine - Google Patents

Description

  The present invention relates to a water-cooled engine configured to cool an engine body by circulating cooling water in the engine body.

  Conventionally, in vehicles such as automobiles, the engine main body is circulated through a water jacket formed inside a cylinder block and a cylinder head (engine main body) and a radiator installed at the front of the vehicle. The cooling has been done.

  By the way, in the field of automobile manufacture, in order to reduce the development cost while increasing the number of vehicle variations, the common use of the engine between the FR (front engine rear drive) vehicle and the FF (front engine front drive) vehicle is attempted. Things have been done. In this case, the FR vehicle has the engine mounted on the vehicle in a vertical position in which the cylinder row direction is parallel to the vehicle longitudinal direction (referred to as a vertical layout), while the FF vehicle has the cylinder row direction orthogonal to the vehicle longitudinal direction. The engine is mounted on the vehicle in a horizontal position (referred to as a horizontal layout). For this reason, the FR vehicle and the FF vehicle differ in the positional relationship between the coolant inlet / outlet (introducing / extracting unit) and the radiator in the engine body, making it difficult to share the engine cooling system.

  In Patent Document 1, at the time of casting a cylinder head, cooling water outlets are formed in closed states on different side surfaces of the cylinder head, and either one of the cooling water outlets is provided depending on the engine layout. It is disclosed that an opening is used for additional processing.

JP 2011-1841 A

  However, in the thing of patent document 1, although the position of a cooling water exit can be selected, the position of a cooling water inlet cannot be selected. Therefore, the positional relationship between the cooling water outlet and the cooling water inlet is different between the FF vehicle and the FR vehicle, and a difference occurs in the state of the cooling water flow in the engine body. In addition, when the distance between the cooling water inlet and the radiator is greatly different between the FF vehicle and the FR vehicle, different piping and accessories connecting the cooling water inlet and the radiator are required. It is difficult to make the cooling system common between the two. In addition, when any cooling water outlet is selected, additional work is required, which increases the manufacturing cost of the engine.

  The present invention has been made in view of the above circumstances, and in the case where a common engine is installed in a vehicle by selecting either a vertical layout or a horizontal layout, a common engine cooling system is used. It aims at providing the water cooling type engine which contributes to.

In order to solve the above-described problems, the present invention provides a water-cooled engine having a reciprocating engine body including a cylinder block and a cylinder head and having a cooling water passage formed therein, the cylinder row direction The parallel direction is defined as the front-rear direction of the engine, the rotation output side of the crankshaft is defined as the rear side of the engine, the direction orthogonal to the front-rear direction is the width direction of the engine, and intake air is directed to the engine body in the width direction. Cylinder that extends in the front-rear direction through the center of each cylinder when the introduction side is defined as the intake side of the engine and the exhaust side is defined as the exhaust side of the engine. Cooling water that has passed through the cooling water passage and the introduction portion for introducing the cooling water from the radiator into the cooling water passage are sent to the radiator at a position closer to the intake side than the axis. Deriving unit and is provided for the cooling water passage, the introduction passage leading to the inlet section, and a discharge passage leading to the outlet portion, said inlet passage and said discharge passage is arranged in the vertical direction width It extends in the direction .

According to this water-cooled engine, both the introduction part and the outlet part of the cooling water are provided on the side wall on the front side of the engine body and on the intake side with respect to the cylinder axis. Even in the case of this layout, the cooling water inlet and outlet can be arranged relatively close to the radiator. In other words, in the case of the horizontal layout, the engine is usually installed in such a posture that the intake side is located on the front side of the vehicle, so that the introduction part and the lead-out part are provided at a position on the intake side from the cylinder axis. According to this, the cooling water introduction part and the discharge part can be arranged relatively close to the radiator, and the positional relationship between the introduction part and the discharge part is constant in both of the vertical and horizontal layouts. Can keep. Therefore, the flow state of the cooling water in the engine body can be kept constant between the two layouts, and it is advantageous in sharing piping and accessories that connect the radiator and the engine body. Therefore, this water-cooled engine contributes to the common use of the cooling system when the common engine is installed in a vehicle with either a vertical or horizontal layout selected.
In addition, since the introduction passage and the lead-out passage are aligned in the vertical direction and extend in the width direction, the introduction portion and the lead-out portion are provided on the side wall on the front side of the engine body while suppressing the enlargement of the engine body in the front-rear direction. It can be provided in a consolidated manner.

  In the above-described water-cooled engine, it is preferable that the introduction part and the lead-out part are provided at a position in the vicinity of the side surface on the intake side of the engine body on the front side wall of the engine body.

  According to this configuration, when the engine is mounted on the vehicle in a horizontal layout, the introduction part and the lead-out part can be arranged at a position closer to the radiator.

  In the above-described water-cooled engine, it is preferable that the introduction part and the lead-out part are provided on a front side wall of the cylinder head.

  According to this configuration, it is possible to provide the introduction portion and the lead-out portion on the front wall surface of the engine body while ensuring a sufficient space for arranging the auxiliary machines assembled on the front wall surface of the cylinder block, such as an alternator and an air compressor. It becomes possible.

  Further, the water-cooled engine includes a cooling water pump assembled to the engine body, and the cooling water pump is disposed on the front side wall of the cylinder block and exhausted from the position of the cylinder axis. It is assembled at the side position.

  In this way, a cooling water pump that is relatively heat resistant (because the cooling water circulates) is assembled at a position closer to the exhaust side than the cylinder axis, so that compared to a cooling water pump such as an alternator or an air compressor. It is possible to dispose auxiliary machinery that is vulnerable to heat mainly at a position on the intake side on the front side of the cylinder block. Therefore, it becomes possible to assemble a plurality of auxiliary machines on the front side wall of the engine body (cylinder block) with a reasonable arrangement according to their heat resistance.

  As described above, according to the water-cooled engine of the present invention, when a common engine is installed in a vehicle with either a vertical layout or a horizontal layout selected, it contributes to the common use of the engine cooling system. To be.

1 is a front view of a water-cooled engine of the present invention. It is a top view of the water-cooled engine. It is a front view of a cylinder block and a cylinder head. It is sectional drawing (IV-IV sectional view taken on the line of FIG. 3) of a cylinder block. It is sectional drawing (VV sectional view taken on the line of FIG. 3) of a cylinder block. It is sectional drawing (the VI-VI sectional view taken on the line of FIG. 3) of a cylinder head. It is sectional drawing (VII-VII sectional view taken on the line of FIG. 3) of a cylinder head. It is a schematic diagram which shows the positional relationship of an engine and a radiator, (a) has shown each positional relationship in the case of a vertical installation layout of an engine, (b) has each in the case of a horizontal installation layout of an engine.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

<Overall configuration>
1 and 2 show a water-cooled engine according to the present invention, FIG. 1 is a front view, and FIG. 2 is a plan view showing the water-cooled engine.

  A water-cooled engine (hereinafter simply referred to as an engine) includes an engine main body 1, an intake manifold 7, an exhaust manifold (not shown), and accessories that are assembled to the engine main body 1.

  The engine body 1 includes a cylinder head cover 2, a cylinder head 3, a cylinder block 4, a crankcase 5, and an oil pan 6, and the cylinder head cover 2 and the like are stacked in this order and integrally connected. In this embodiment, the engine body 1 is an in-line four-cylinder reciprocating engine in which four cylinders (first to fourth cylinders # 1 to # 4 / shown in FIG. 4 and the like) are arranged in series. Are formed with four substantially cylindrical cylinders arranged in a row. In each cylinder bore 20 (shown in FIGS. 4 and 5), unillustrated pistons are inserted so as to be reciprocally slidable, and fuel and air are mixed in a combustion chamber defined above each piston. When the air burns, the piston reciprocates due to the expansion energy generated by the combustion, and the reciprocating motion of the piston is converted into the rotational motion of the crankshaft 8 and output to the transmission side.

  The engine body 1 is a so-called cross-flow engine, and an intake system including an intake manifold 7 and an exhaust system including an exhaust manifold are provided on one side and the other side in a direction orthogonal to the cylinder row direction. In the following description, the cylinder row direction is referred to as the front-rear direction of the engine (engine body 1), and the direction perpendicular thereto is referred to as the width direction, and the side of the engine where the rotational force of the crankshaft 8 is output. After (transmission side), the opposite side is called front. That is, FIG. 1 depicts the engine from the front side. Further, the axial direction of the cylinder is referred to as the vertical direction, the cylinder head side is referred to as the upper side, and the counter cylinder head side is referred to as the lower side.

  An alternator 10, an air compressor 11, a water pump 14 (cooling water pump) and the like are assembled on the front side wall of the engine body 1 as the auxiliary machines. Among these auxiliary machines, the alternator 10 and the air compressor 11 are provided at a position closer to the intake side than the cylinder axis La extending in the front-rear direction through the centers of the cylinders # 1 to # 4 in the engine body 1. Yes. On the other hand, the water pump 14 is provided at a position on the exhaust side of the cylinder axis La. In FIG. 1 and FIG. 3, in order to show the position of the cylinder axis La, an axis perpendicular to the cylinder axis La is drawn, and the symbol La is shown in parentheses.

  The alternator 10 and the air compressor 11 are equipped with pulleys 10a and 11a, respectively, and a conductive belt 12 spans between the pulleys 10a and 11a and the pulley 8a attached to the end of the crankshaft 8. Has been. Similarly, a pulley 14 a is attached to the water pump 14, and a conductive belt 15 is stretched over the pulley 14 a and the pulley 8 a of the crankshaft 8. Thereby, the rotational driving force of the crankshaft 8 is transmitted to the alternator 10, the air compressor 11 and the water pump 14 through the conduction belts 12 and 15, respectively, and the auxiliary machines such as the alternator 10 are driven.

  Each of the cylinder head 3 and the cylinder block 4 is formed with a water jacket (corresponding to the cooling water passage of the present invention), and the cooling water pumped from the water pump 14 flows along the fora jacket. Thus, the engine body 1 including the cylinder head 3 and the cylinder block 4 is cooled. Specifically, the cooling water discharged from the water pump 14 first flows into the cylinder block 4, then flows into the cylinder head 3, and then is led out of the engine body 1. The cooling water led out of the engine body 1 radiates heat with a radiator (not shown) provided separately from the engine, is returned to the engine body 1, and the flow rate adjustment valve 16 assembled to the engine body 1 is installed. Through the water pump 14. Thus, the engine main body 1 is continuously cooled by repeating heat absorption in the engine main body 1 and heat dissipation in the radiator while cooling water circulates between the engine main body 1 and the radiator.

<Detailed structure of the water jacket etc. of the engine body 1>
3 is a front view of the cylinder head 3 and the cylinder block 4, FIGS. 4 and 5 are sectional views of the cylinder block 4, and FIGS. 6 and 7 are sectional views of the cylinder head 3, respectively.

  The cylinder block 4 includes a block main body 4a that occupies most of the cylinder block 4 and a housing part 4b that is fixed to the front end surface thereof. Both the block body 4a and the housing part 4b are made of a metal casting such as die-casting of an aluminum alloy.

  The cylinder body 4a is formed with the four cylinders arranged in a line in the front-rear direction. The cylinder bores 20 of the cylinders are coupled to each other, and a cylinder bore wall 20a surrounding the four cylinders is formed in the block body 4a. As a water jacket for the cylinder block 4, a block-side jacket 22 is formed along the cylinder bore wall 20a so as to surround the cylinder bore wall 20a. The block-side jacket 22 is an endless concave groove that is recessed downward, and opens to the upper surface of the block body 4a over the entire circumference.

  The housing part 4b is fixed to the front end surface of the block body 4a and forms the pump housing of the water pump 14 together with the block body 4a. That is, as shown in FIG. 4, a substantially circular recess 34a is formed on the front end surface of the block body 4a, while a substantially circular recess 34b is similarly formed on the mating surface of the housing part 4b with the block body 4a. The volute chamber 34 in which the impeller (not shown) of the water pump 14 is accommodated is formed by the recesses 34a and 34b.

  The housing part 4b is integrally formed with a cooling water discharge passage 36 which communicates with the volute chamber 34 and extends to the intake side. The discharge passage 36 communicates with the block-side jacket 22 through an opening 22a formed on the front side wall of the block body 4a. That is, the cooling water discharged from the water pump 14 is directly introduced into the block-side jacket 22 through the inside of the cylinder block 4.

  As shown in FIG. 6, the cylinder head 3 includes, as a water jacket, a first head side jacket 24 positioned on the upper side (on the opposite side of the cylinder block) and a second head side jacket positioned on the lower side (cylinder block side). 26 is formed. These head side jackets 24 and 26 extend in the front-rear direction from the first cylinder to the fourth cylinder, respectively.

  The first head side jacket 24 is provided in a portion corresponding to the combustion chambers of the respective cylinders # 1 to # 4, and the second head side jacket 26 is disposed on the exhaust side from the combustion chambers of the respective cylinders # 1 to # 4. It is provided in the close part. The first head-side jacket 24 is located above the second head-side jacket 26 in a front view of the cylinder head 3, and therefore, although not shown in detail, both the head-side jackets 24, 26 have many It overlaps with the part.

  As shown in FIG. 1, a post-cooling passage 42 for cooling water is formed on the front side wall of the cylinder head 3, and the first head-side jacket 24 communicates with the lead-out passage 42. The first head side jacket 24 and the second head side jacket 26 communicate with each other at the position of the front end portion of the cylinder head 3 through a communication path (not shown). Also, the head side jackets 24 and 26 of the cylinder head 3 and the block side jacket 22 of the cylinder block 4 are gasket openings (not shown) interposed between the cylinder head 3 and the cylinder block 4, respectively. Specifically, they communicate with each other through an opening formed at a position corresponding to the cylinder of the fourth cylinder # 4. That is, the cooling water introduced from the water pump 14 to the block side jacket 22 generally flows in the cylinder block 4 from the front side to the rear side along the block side jacket 22, and After flowing into the head-side jackets 24 and 26 of the cylinder head 3 through the openings and flowing through the cylinder head 3 from the rear side to the front side along the head-side jackets 24 and 26, the first head-side jacket 24. It is derived from the first head side jacket 24 while merging at the position of the front end of the first head side jacket 24.

  As shown in FIG. 3, on the front side wall of the cylinder head 3, an introduction portion 30 for introducing cooling water from the radiator into the engine body 1 and a derivation for extracting cooling water from the engine body 1. Part 40 is provided. The introduction part 30 and the lead-out part 40 are provided side by side in the vertical direction at a position near the side surface on the intake side of the cylinder head 3. Specifically, the introduction part 30 is provided on the lower side, and the lead-out part 40 is provided on the upper side. The introduction part 30 has an opening 30 a facing the outside in the width direction of the engine body 1, in this example, the intake side, and the lead-out part 40 has an opening 40 a facing the front of the engine body 1. Both the introduction part 30 and the lead-out part 40 are formed integrally with the cylinder head 3.

  The introduction portion 30 communicates with the volute chamber 34 of the water pump 14 through an introduction passage 32 formed in the cylinder head 3 and the cylinder block 4.

  As shown in FIGS. 3 to 6, the introduction passage 32 includes a first passage portion 32 a extending from the introduction portion 30 across the front of the head side jackets 24, 26 in the width direction along the front side surface of the cylinder head 3. And a second passage portion 32b that extends downward from the end portion on the exhaust side of the first passage portion 32a to the inside of the cylinder block 4 and the cylinder head 3 and communicates with the volute chamber 34. As shown in FIGS. 1 and 2, the flow rate adjusting valve 16 is connected to the introduction unit 30, and the cooling water from the radiator is introduced into the engine body 1 through the flow rate adjusting valve 16. The In addition, the code | symbol 16a in FIG. 2 is the inlet side port part of the flow regulating valve 16, and is formed in the cylinder shape.

  The lead-out portion 40 communicates with the first head-side jacket 24 through a lead-out passage 42 formed inside the cylinder head 3. As shown in FIGS. 3 and 7, the lead-out passage 42 extends from the lead-out portion 40 to the exhaust side along the front side surface of the cylinder head 3 from the lead-out portion 40 to the upper side of the introduction passage 32 (first passage portion 32a). The first head side jacket 24 communicates with the cylinder axis La. A pipe joint 44 bent in an L shape is fixed to a position corresponding to the lead-out portion 40 in the front side wall of the cylinder head 3. The pipe joint 44 communicates with the lead-out passage 42 through the opening 40a.

  In this embodiment, the jackets 22, 24, 26, the introduction passage 32, the discharge passage 42, the discharge passage 36 of the water pump 14 and the like correspond to the cooling water passage of the present invention.

<Effect>
FIGS. 8A and 8B schematically show a state where the engine is mounted on a vehicle. More specifically, FIG. 8A shows an example in which the engine is mounted on an FR (front engine rear drive) vehicle, and the engine is in a vertically installed posture in which the cylinder row direction is parallel to the vehicle front-rear direction. Installed in the vehicle (vertical layout). On the other hand, FIG. 8B shows an example in which the engine is mounted on an FF (front engine front drive) vehicle, and the engine is mounted on the vehicle in a horizontal posture in which the cylinder row direction is orthogonal to the vehicle front-rear direction. Yes (horizontal layout). In addition, the code | symbol 50 in a figure has shown the radiator installed in the front part of the vehicle. Reference numeral 51 denotes an introduction side pipe for guiding the cooling water from the radiator 50 to the engine main body 1, and reference numeral 52 denotes an outlet side pipe for guiding the cooling water derived from the engine main body 1 to the radiator 50. The introduction side pipe 51 is connected across the radiator 50 and the flow rate adjusting valve 16 (port portion 16a) of the engine body 1, and the outlet side pipe 52 is connected to the radiator 50 and the pipe joint 44 of the engine body 1. Connected.

  As shown in these drawings, according to the engine, both the cooling water introduction part 30 and the lead-out part 40 are provided on the front side wall of the engine body 1 and in the vicinity of the side surface on the intake side. The cooling water introduction part 30 and the lead-out part 40 can be arranged at a position relatively close to the radiator 50 in both the vertical and horizontal layouts. For this reason, it is advantageous in sharing pipes 51 and 52 connecting the radiator 50 and the engine body 1 and accessories. That is, in either one of the vertical and horizontal layouts, when the introduction part 30 or the lead-out part 40 is far away from the radiator 50, a pipe structure in which the pipe 51 or 52 is largely routed around the engine body 1 is provided. It may be required and it may be required to change the type of either the pipe 51 or 52 in order to protect it from the heat of the engine body 1. However, according to the engine, the cooling water inlet 30 and outlet 40 are located near the radiator 50, as shown in FIGS. 8 (a) and 8 (b), in both the vertical and horizontal layouts. Therefore, the engine main body 1 and the radiator can be connected without difficulty using, for example, common pipes 51 and 52 and accessories.

  In addition, according to the engine, the positional relationship between the introduction unit 30 and the derivation unit 40 can be kept constant in both the vertical and horizontal layouts. Therefore, the flow state of the cooling water in the engine body 1 can be kept constant between both layouts. Specifically, in both the vertical and horizontal layouts, the cooling water is introduced into the engine body 1 from the introduction unit 30 via the flow rate adjustment valve 16 and sucked into the water pump 14 through the introduction passage 32. It is discharged (introduced) from the discharge passage 36 into the block side jacket 22 of the cylinder block 4. As described above, the cylinder block 4 flows from the front side to the rear side along the block side jacket 22 and flows into the head side jackets 24 and 26 of the cylinder head 3 through the opening of the gasket. After flowing in the cylinder head 3 along the side jackets 24 and 26 from the rear side to the front side, the cylinder head 3 joins at the position of the front end portion of the first head side jacket 24 and passes through the lead-out passage 42 to lead-out part 40 (pipe joint 44). ) To the outside of the engine body 1.

  Therefore, according to the engine, there is an advantage that it contributes to common use of the cooling system of the engine body 1 when the layout of either one of the vertical installation and the horizontal installation is selected and mounted on the vehicle.

  In particular, according to the engine, the introduction part 30 and the lead-out part 40 are provided in the cylinder head 3, so that the alternator 10, the air compressor 11, the water pump 14 and the like assembled on the front side wall of the cylinder block 4 are supplemented. There is an advantage that the introduction part 30 and the lead-out part 40 can be provided without difficulty on the side wall on the front side of the engine body 1 while securing the installation space for the machinery. Moreover, since the introduction passage 32 (first passage portion 32a) and the lead-out passage 42 extend in the width direction along the front side surface of the engine body 1 side by side in the vertical direction, the engine body 1 is large in the front-rear direction. There is an advantage that the introduction part 30 and the lead-out part 42 can be provided in an integrated manner on the front side wall of the engine body 1 while preventing the engine body 1 from being changed. That is, if the introduction passage 32 and the lead-out passage 42 are arranged in the longitudinal direction of the engine, the size of the cylinder head 3 in the longitudinal direction is accompanied by the amount of space occupied separately in the longitudinal direction. However, according to the engine, the space occupied by the passages 32 and 42 is overlapped in the front-rear direction, so that the cylinder head 3 in the front-rear direction is not enlarged, and the front side wall of the engine body 1 is formed. The introduction part 30 and the lead-out part 40 can be arranged in an integrated manner.

  Further, according to the engine, the water pump 14 that is relatively heat resistant (because the coolant flows) is assembled at a position closer to the exhaust side than the position of the cylinder axis La, so that the cylinder block 4 As compared with the water pump 14 such as the alternator 10 and the air compressor 11, it is possible to dispose auxiliary devices that are weak against heat, mainly at the position on the intake side. Therefore, according to the above engine, there is an advantage that a rational configuration in which a plurality of auxiliary machines are assembled to the front side wall of the engine body 1 (cylinder block 4) in an arrangement that matches their heat resistance is achieved. is there.

  Further, according to the engine, no additional work such as a cylinder head 3 or the like like this conventional engine (the engine described in Patent Document 1 described in the background art) is unnecessary regardless of the layout of the engine. Therefore, there also exists an advantage that the above operation effects can be enjoyed, without accompanying the increase in the manufacturing cost by the said additional work.

  The engine described above is an example of a preferred embodiment of the water-cooled engine according to the present invention, and the specific configuration thereof can be appropriately changed without departing from the gist of the present invention.

  For example, in the above embodiment, the jackets 22, 24, 26, etc. are provided as the cooling water passages of the present invention, and the cooling water introduced into the block side jacket 22 moves from the front side to the rear side in the cylinder block 4. The cooling water passage is formed so as to flow into the head side jackets 24 and 26 of the cylinder head 3 and flow from the rear side to the front side in the cylinder head 3. The configuration is not limited to this. What is necessary is just to be provided suitably so that the engine main body 1 can be cooled appropriately.

  Further, in the above embodiment, the introduction portion 30 and the lead-out portion 40 are provided on the intake side of the front side wall of the cylinder head 3, more specifically, at a position near the side surface on the intake side of the cylinder head 3. However, it is not limited to this. The introduction part 30 and the lead-out part 40 may be provided at positions other than the above as long as they are the side walls on the front side of the cylinder head 3. However, according to the configuration of the above embodiment in which the introduction portion 30 and the lead-out portion 40 are provided in the vicinity of the side surface on the intake side of the cylinder head 3, the introduction portion 30 and the lead-out portion are provided when the engine is in a horizontal layout. Since the part 40 can be disposed at a position closer to the radiator 50, it is advantageous in sharing the cooling system between the vertical and horizontal layouts.

  Moreover, in the said embodiment, although the introduction part 30 and the derivation | leading-out part 40 are provided in the cylinder head 3, it is not limited to this. One or both of the introduction part 30 and the lead-out part 40 may be provided in the cylinder block 4.

DESCRIPTION OF SYMBOLS 1 Engine main body 3 Cylinder head 4 Cylinder block 8 Crankshaft 14 Water pump 30 Introductory part 32 Introducing path 34 Volute chamber 36 Discharge path 40 Deriving part 42 Deriving path 50 Radiator La Cylinder axis

Claims (4)

A water-cooled engine having a reciprocating engine main body including a cylinder block and a cylinder head and having a cooling water passage formed therein,
The direction parallel to the cylinder row direction is defined as the front-rear direction of the engine, the rotational output side of the crankshaft is defined as the rear side of the engine, and the direction perpendicular to the front-rear direction is defined as the engine width direction. On the other hand, when the intake side is defined as the intake side of the engine and the exhaust side is defined as the exhaust side of the engine,
An introduction section for introducing cooling water from the radiator into the cooling water passage at a position on the intake side of a cylinder axis that extends in the front-rear direction through the center of each cylinder in the front side wall of the engine body and cooling A lead-out portion for sending the cooling water flowing through the water passage to the radiator is provided ,
The cooling water passage includes an introduction passage that leads to the introduction portion, and a lead-out passage that leads to the lead-out portion,
The water-cooled engine, wherein the introduction passage and the lead-out passage extend in the width direction side by side in the vertical direction . The water-cooled engine according to claim 1,
The water-cooled engine, wherein the introduction part and the lead-out part are provided in a position near a side surface on the intake side of the engine body, of the front side wall of the engine body. The water-cooled engine according to claim 1 or 2,
The water-cooled engine, wherein the introduction portion and the lead-out portion are provided on a front side wall of the cylinder head. The water-cooled engine according to any one of claims 1 to 3 ,
Including a cooling water pump assembled to the engine body,
The water-cooled engine is characterized in that the cooling water pump is assembled at a front side wall of the cylinder block and at a position on the exhaust side of the position of the cylinder axis.