JPH1182013A - Cooling system for water-cooled internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce resistance of a passage in a cooling water system due to reduction of waterway length, downsize a cooling water pump, reduce the number of items, improve cooling performance, secure attaching accuracy of a radiator in a cooling system for water-cooled internal combustion engine. SOLUTION: In a cooling system for a water-cooled internal combustion engine 1, a radiator 15 having an inlet/outlet port for cooling water is directly attached to an internal combustion engine main body in the vicinity of a cooling water port of the engine main body. The cooling water port of the radiator 15 is connected to that of the internal combustion main body, for preparing a cooling water passage. In such a case, a radiator attaching surface of the engine main body is formed separately from outer surfaces of components having cooling water jackets of the engine main body, that is, a cylinder and a cylinder head. A heat insulative space A is thus formed between the radiator 15 and the outer wall surface. The radiator attaching surface of the internal combustion engine main body is integrated with the components, that is, the cylinder or cylinder head, of the engine main body having the radiator attaching surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for a water-cooled internal combustion engine having a relatively small displacement, for example, a water-cooled internal combustion engine mounted on a small vehicle such as a motorcycle, and more particularly, to a radiator mounting structure. The present invention relates to a device for cooling a water-cooled internal combustion engine.

[0002]

2. Description of the Related Art In a cooling device for a water-cooled internal combustion engine, a radiator having an inlet and an outlet for cooling water is required to shorten the length of a water channel in the cooling water system to reduce the passage resistance. It is preferable that the heat of the internal combustion engine be transmitted to the radiator from a portion other than the radiator mounting portion of the internal combustion engine, preferably in the vicinity of the cooling water inlet / outlet of the main body. Therefore, the cooling performance of the cooling water of the internal combustion engine body by the radiator is reduced.

Conventionally, in this type of cooling apparatus for a water-cooled internal combustion engine, as disclosed in Japanese Utility Model Laid-Open Publication No. 64-3025, a radiator is provided with an air-cooling fan provided adjacent to a crankcase, a cylinder, and a cylinder head. It was directly attached to the air outlet, and was attached without any gap to the cylinder or cylinder head, and no heat insulating space was formed between them.

[0004] For this reason, in addition to water as a cooling medium, heat is transmitted from the internal combustion engine body to the radiator by direct heat conduction, thereby reducing the cooling performance of the radiator for cooling water of a water-cooled internal combustion engine. Therefore, if a heat insulating material is interposed between the radiator and the components (cylinder, cylinder head) of the internal combustion engine body in order to cut off this heat conduction, it has been difficult to secure the mounting accuracy of the radiator.

Further, the mounting position of the radiator is restricted, and even though the radiator is mounted without any gaps with the cylinder or the cylinder head, the radiator is far from the inlet / outlet of the cooling water to the cooling water jacket formed therein. In this case, the water passage length of the cooling water system is increased, the passage resistance is increased, and the pump power is wasted.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a cooling system for a water-cooled internal combustion engine which solves the above-mentioned problems. A radiator having the radiator is directly attached to the internal combustion engine main body in proximity to the inlet / outlet portion of the cooling water of the internal combustion engine main body, and the inlet / outlet of the radiator cooling water and the inlet / outlet of the cooling water of the internal combustion engine main body are connected, In a cooling device for a water-cooled internal combustion engine having a cooling water passage formed therein, the radiator mounting surface of the internal combustion engine main body is provided apart from an outer wall surface of a component having a cooling water jacket of the internal combustion engine main body, and the radiator A heat-insulating space is formed between the water-cooled internal combustion engine and the outer wall surface.

The invention described in claim 1 is configured as described above, and the radiator is mounted directly on the internal combustion engine main body in the vicinity of the inlet / outlet of the cooling water of the internal combustion engine main body. The water path length of the cooling water system is minimized, the passage resistance is greatly reduced, the power consumption of the cooling water pump is reduced, and the cooling water pump can be downsized. at the same time,
The number of parts such as pipes, hoses and bands used in the cooling water system can be reduced.

Moreover, the radiator mounting surface of the internal combustion engine main body is provided separately from the outer wall surface of the component having the cooling water jacket of the internal combustion engine main body, and a heat insulating space is formed between the radiator and the outer wall surface. The heat from the components of the internal combustion engine body is only the heat transmitted to the radiator through the radiator mounting portion, and the other heat is effectively cut off, thereby improving the cooling performance of the water-cooled internal combustion engine by the radiator.

Further, as described above, a heat insulating space is formed between the radiator and the outer wall surface of the component having the cooling water jacket of the internal combustion engine body, and as a result, a heat insulating material is provided between the radiator and the radiator mounting portion. Since it is not necessary to interpose the radiator, the mounting accuracy of the radiator is ensured.

Further, by configuring the invention according to claim 1 as described in claim 2, no special parts are required for mounting the radiator, the number of parts is further reduced, and the radiator mounting portion is further reduced. The simplification of the structure facilitates the manufacture of a cooling device for a water-cooled internal combustion engine.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a first embodiment of the present invention; FIG. FIG. 1 is a partially cut-away schematic left side view of a cooling device for a water-cooled internal combustion engine according to the present embodiment, and shows a partial cross-sectional view cut along lines II and ii in FIG. FIG. 2 is a sectional view taken along the line II in FIG.
FIG. 2 is a vertical cross-sectional plan view cut along a line II, in which only a cooling water pump mounting portion is a view in which cross-sectional views cut along a line ii-ii are superimposed. FIG. 3 shows FIGS. 1 and 2
FIG. 3 is a schematic cross-sectional view cut along the line III-III of FIG. In FIGS. 1 and 2, illustration of portions below the piston and the crank portion is omitted, and in FIGS. 1 and 3, the detailed structure of the radiator is omitted.

The water-cooled internal combustion engine 1 according to the present embodiment
An overhead valve type four-stroke cycle (commonly called four-cycle) single-cylinder internal combustion engine, which is located on the body of a small motorcycle (not shown), which is located between the front and rear wheels, and whose cylinder axis is oriented substantially in the horizontal direction. , Has been installed.

The cylinder and the cylinder head, which are the main parts of the water-cooled internal combustion engine 1, are integrally formed as one cylinder block 2 together with the cylinder head cover.

An intake port 5 and an exhaust port 6 communicating with the combustion chamber 4 at the top of the cylinder hole 3 are formed in a cylinder head equivalent portion 2b of the cylinder block 2, respectively.
An intake valve 7 and an exhaust valve 8 are provided at the intake port 5 and the exhaust port 6, respectively, so as to be freely opened and closed.

A camshaft 9 is disposed adjacent to the top ends of the intake valve 7 and the exhaust valve 8.
Part 2 equivalent to cylinder head cover of cylinder block 2
Two large and small bearing holes 11, 12 formed at two places on the left and right of c
And is rotatably supported via a bearing 10.

A driven sprocket 13 is integrally connected to and attached to the left end enlarged diameter portion 9a of the camshaft 9, and an endless chain (power transmission) is attached to the driven sprocket 13 and a drive sprocket integrated with a crankshaft (not shown). Mechanism) 14 is bridged and the camshaft 9
Is driven to rotate at half the rotational speed of the crankshaft, and the intake valve 7 and the exhaust valve 8 are each opened and closed once each time the crankshaft rotates twice.

As shown in FIGS. 1 and 2, a radiator 15, which is a radiator of a cooling device for cooling the water-cooled internal combustion engine 1, extends over a portion 2a corresponding to the cylinder and a portion 2b corresponding to the cylinder head of the cylinder block 2. The radiator mounting pedestal 22 protruding from the cylinder block 2 corresponding to these locations at two locations before and after the flange portion 20a at the lower peripheral edge of the radiator mounting pedestal 22 is disposed directly above the bolts 21. Attached and securely fixed.

The radiator mounting surface of the radiator mounting pedestal 22 is formed so as to be sufficiently separated from the outer wall surfaces of the cylinder-corresponding portion 2a and the cylinder head-corresponding portion 2b, whereby the bottom wall 20 of the radiator 15 connected to the flange portion 20a is formed. Between these outer walls, the radiator
A heat insulating space A sufficient to block heat transfer to 15 is formed.

Although not shown in detail, the radiator 15 has upper and lower tanks, and these upper and lower tanks are connected by a plurality of vertically arranged cooling water conduits. Radiation fins composed of a plurality of plate-like members are penetrated by the cooling water conduits and attached to the conduits in a stacked manner.

The cylinder-equivalent part 2 of the cylinder block 2
As shown in FIGS. 1 and 3, radiator connection pedestals 23 and 24 for projecting fluid communication with the radiator 15 are protrudingly provided on the left and right sides above the a. The radiator connection pedestal 24 (on the right side in FIG. 3) has an outlet passage 26a communicating with the discharge passage 26 of the cooling water pump 30.
Is formed at the upper opening of the outlet passage 26a.
A lower end of the communication pipe 18 is fitted, and an upper end of the communication pipe 18 is connected to an upper tank (not shown). This allows the cooling water discharged from the cooling water pump 30 to flow through the discharge passage 26 and the outlet passage.
26a flows through the communication pipe 18 and flows into the upper tank of the radiator 15.

The radiator connection pedestal 23 on the right side (the left side in FIG. 3) is formed with a cooling water inlet passage 25 for guiding the cooling water cooled in the radiator 15 to a cooling water jacket 19 described later. The lower end of the communication pipe 16 is fitted into the upper opening of the passage 25, and the upper end of the communication pipe 16 is
It is connected to the lower tank 17. Thereby, the cooling water cooled in the radiator 15 flows from the lower tank 17 through the inlet passage 25 in the communication pipe 16 and returns to the cooling water jacket 19.

The lower ends of the communication pipes 16 and 18 are connected to the entrance passage 2.
5, a portion fitted to each upper opening of the outlet passage 26a,
The portions where the communication pipes 16 and 18 penetrate the bottom wall 20 of the radiator 15 are provided with sealing members 27 and 28 for simultaneously securing watertightness of these portions, and the communication pipe 16 and the radiator connection pedestal 23 and the bottom wall.
Between 20, and the communication pipe 18 and the radiator connection base 24 and the bottom wall 20
In between, each is interposed.

The cooling water pump 30 is a magnet coupling type cooling water pump. The cooling water pump 30 extends over the cylinder-equivalent portion 2a and the cylinder head-equivalent portion 2b of the cylinder block 2 and is provided on the left side wall in FIG. The large-diameter portion 32a of the casing 32 is fitted in the hole 31 in a watertight manner, and the small-diameter portion 32 of the casing 32 is formed by the wall surface of the cover 40 that covers the left side surface of the cylinder block 2.
The bottom of b is supported and mounted.

Large diameter portion 32 of casing 32 of cooling water pump 30
a is composed of two parts, a part integral with the small diameter part 32b and a part separate from the small diameter part 32b, in which the blade part of the impeller 34 is housed, and discharge of pressurized cooling water The part 44 and the discharge passage 26 are formed.

Also, as shown in FIG.
A portion of the bottom wall 32c where the bottom wall 32c meets the cooling water jacket 19 is cut away to form a cooling water suction portion 43 of the cooling water pump 30. The small diameter portion 32b functions as a partition in the magnet coupling portion of the cooling water pump 30.

The support shaft 33 of the impeller 34 has one end supported at the bottom of the small diameter portion 32a of the casing 32, and the other end supported by the wall surface of the cylinder block 2 where the cooling water jacket 19 is formed across the suction portion 43. Have been. The mounting position is set in the front-rear direction (in the cylinder axis direction and in the left-right direction in FIG. 1) so as to coincide with the projecting positions of the radiator connection pedestals 23 and 24 (see FIGS. 1 and 3). ). On the outer peripheral surface of the shaft portion 34a of the impeller 34,
A plurality of permanent magnets 35 are provided integrally in the circumferential direction.

As shown in FIG. 2, the pump mounting hole 31 has a front-rear position (a position in the axial direction of the cylinder) extending vertically above the combustion chamber 4 and is adjacent to the cylinder chamber and the exhaust port 6. It is formed. The cooling water jacket 19 is also formed to extend back and forth with the periphery of the combustion chamber 4 as a center, so that the formation position of the pump mounting hole 31 where the cooling water pump 30 is installed is 19 is substantially covered in the front-back direction.

The radiator 15 is provided at least at the installation position of the cooling water pump 30 (the pump mounting hole 31).
It is desirably provided so as to fall within the range of front and rear positions determined by the formation position of the cooling water jacket 19 (the range surrounded by two chain lines in FIG. 2).
By doing so, the water path length of the cooling water system can be made extremely short.

The space between the cylinder block 2 and the cover 40 is a transmission mechanism chamber 42 in which the endless chain 14 is housed. A driven sprocket 36 is rotatably supported by a bearing of the cover 40 via a bearing 38, surrounding the small diameter portion 32b of the casing 32 of the cooling water pump 30.
On the inner peripheral surface of the driven sprocket 36, a cooling water pump
A plurality of permanent magnets 37 facing the 30 permanent magnets 35 are provided integrally in the circumferential direction.

When the driven sprocket 36 is driven to rotate by the rotation of the endless chain 14, the shaft 34a of the impeller 34 of the cooling water pump 30 magnetically connected to the driven sprocket 36 by the permanent magnets 35 and 37. , And is rotationally driven.

The right side (the left side in FIG. 3) of the cylinder block 2 is largely covered by a cover 41 as shown in FIGS. 2 and 3, and the cover 41 is formed with fins. The part of the fin planting wall 41b, which is the bottom wall, of the portion 41a is recessed, and forms a part of the wall surface of the cooling water jacket 19.

As shown in FIG. 3, the upper portion of the fin forming portion 41a, which is slightly forward of the center of the fin installation wall 41b in the front-rear direction (vertical direction in FIG. 2) and closer to the radiator 15, is not depressed. A water receiving portion 25a for receiving the cooling water flowing back through the inlet passage 25 from the lower tank 17 of the radiator 15 through the communication pipe 16 is formed, and the returned cooling water passes through the water receiving portion 25a and is returned. It is divided into right and left, and flows into the entire area of the cooling water jacket 19. Cover 41
Is formed with an intake passage 5a connected to the intake port 5.

Since the first embodiment is configured as described above, the following operations and effects can be obtained. The water-cooled internal combustion engine 1 is in an operating state, and a driven sprocket 36 is rotationally driven by an endless chain 14 that rotates in accordance with the operation of the water-cooled internal combustion engine 1, and a cooling water pump magnetically coupled to the driven sprocket 36. When the shaft portion 34a of the impeller 34 is rotationally driven, the impeller 34
The cooling water heated by the cooling water jacket 19 and heated to a high temperature is sucked from the suction part 43 by the cooling water pump 30 and pressurized, and is discharged, the discharge part 44, the discharge passage 26, and the outlet passage 26.
a, and then flows through the communication pipe 16 and flows into an upper tank (not shown).

The cooling water flowing into the upper tank is divided into a plurality of cooling water conduits (not shown) and flows thereinto. The cooling water is effectively radiated through the radiation fins by the traveling wind flowing from the front to the rear, and flows into the lower tank 17. . The cooling water flowing into the lower tank 17 then flows through the communication pipe 16, the inlet passage 25, and the water receiving portion 25a, returns to the cooling water jacket 19, and circulates through the cooling water system.

The radiator 15 includes a radiator connection base 23,
At a position substantially at the same height as 24, the cooling water passage is formed by being directly mounted on the radiator mounting pedestal 22 and being in fluid communication with the cylinder block 2 at the radiator connection pedestals 23 and 24. The length is shortest, the passage resistance is greatly reduced, the power consumption of the cooling water pump 30 is reduced, and the cooling water pump 30 can be downsized. Further, since the length of the water channel in the cooling water system is the shortest, the number of parts such as pipes, hoses, and bands used in the cooling water system can be reduced.

Moreover, although the radiator 15 is directly mounted on the radiator mounting pedestal 22, the radiator mounting surface of the radiator mounting pedestal 22 has the cylinder-equivalent portion 2a and the cylinder head-equivalent portion 2a of the cylinder block 2.
b is formed far away from the outer wall of the radiator
Since a sufficient heat insulating space A is formed between the bottom wall 20 connected to the flange portion 20a and the outer wall surface to block heat transfer from the outer wall surface to the radiator 15, the internal combustion engine body Is conducted only through the radiator mounting portion, and the other heat is effectively blocked, and the cooling performance of the water-cooled internal combustion engine 1 by the radiator 15 is improved.

Further, since the heat insulating space A is formed between the radiator 15 and the outer wall surfaces of these components of the internal combustion engine main body, there is no need to interpose a heat insulating material between them including the radiator mounting portion. Thus, the mounting accuracy of the radiator 15 is ensured.

The radiator mounting surface is formed on a radiator mounting base 22. Since the radiator mounting base 22 is integrally formed with the cylinder block 2 so as to protrude therefrom, special parts for mounting the radiator 15 are provided. Becomes unnecessary,
The number of parts is further reduced, the structure of the radiator mounting portion is simplified, and the manufacture of the cooling device for the water-cooled internal combustion engine 1 is facilitated.

In the above embodiment, the cooling water pump 30
Is a magnet coupling type cooling water pump, but may be a normal type cooling water pump instead.In this case, the shaft portion 34a of the impeller 34 of the cooling water pump 30 is It is directly connected to the driven sprocket 36 without using a magnetic coupling.

The radiator 15 is directly mounted on the radiator mounting base 22. Alternatively, the radiator 15 may be directly mounted on the radiator connection bases 23 and 24.
In this case, the radiator connection pedestals 23 and 24 also serve as a portion for forming a mounting surface of the radiator 15 and a portion for communicating cooling water between the radiator 15 and the cylinder block 2. Then, the radiator mounting base 22 is abolished. The radiator mounting base 22 is not abolished, and the radiator mounting base 22,
It goes without saying that the radiator 15 may be directly attached to the radiator connection pedestals 23 and 24 by using all of them.

Further, in the water-cooled internal combustion engine 1, the cylinder and the cylinder head, which are main parts of the internal combustion engine, are formed integrally with the cylinder head cover as one cylinder block 2, but the invention is not limited to this. May be a separate type of water-cooled internal combustion engine, which is formed separately and integrally connected.

[Brief description of the drawings]

FIG. 1 is a partially cut-away schematic left side view of a cooling device for a water-cooled internal combustion engine according to an embodiment of the present invention described in claims 1 and 2; FIG.
FIG. 3 is a partial cross-sectional view cut along the -i line and shown in an overlapped manner.

FIG. 2 is a vertical cross-sectional view taken along the line II-II of FIG. 1, and is a view in which only a cooling water pump mounting portion is overlapped with a cross-sectional view taken along the line ii-ii.

FIG. 3 is a schematic cross-sectional view cut along the line III-III of FIGS. 1 and 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Water-cooled internal combustion engine, 2 ... Cylinder block, 2a ... Cylinder equivalent part, 2b ... Cylinder head equivalent part, 2c
... Cylinder head cover equivalent part, 3 ... Cylinder hole, 4
... combustion chamber, 5 ... intake port, 5a ... intake passage, 6 ... exhaust port, 7 ... intake valve, 8 ... exhaust valve, 9 ... camshaft,
9a ... left end enlarged diameter part, 10 ... bearing, 11, 12 ... bearing hole,
13 ... driven sprocket, 14 ... endless chain (transmission mechanism), 15 ... radiator, 16 ... communication pipe, 17 ... lower tank,
18 ... communication pipe, 19 ... cooling water jacket, 20 ... bottom wall, 20a ...
Flange part, 21 ... bolt, 22 ... radiator mounting base, 2
3, 24: radiator connection pedestal, 25: inlet passage, 25a: water receiving part, 26: discharge passage, 26a ... outlet passage, 27, 28 ... sealing member, 30 ... cooling water pump, 31 ... pump mounting hole, 32 ... Casing, 32a ... Large diameter part, 32b ... Small diameter part, 32c ... Bottom wall, 33
... support shaft, 34 ... impeller, 34a ... impeller shaft, 35 ... permanent magnet, 36 ... driven sprocket, 37 ... permanent magnet, 38
... bearings, 40, 41 ... cover, 41a ... fin forming part, 41b ...
Fin installation wall, 42: transmission mechanism room, 43: suction unit, 44: discharge unit, A: heat insulating space.

Claims (2)

[Claims] 1. A radiator having an inlet and an outlet for cooling water,
The cooling water passage of the radiator is connected directly to the cooling water inlet / outlet of the internal combustion engine main body, and the cooling water passage is connected to the cooling water inlet / outlet portion of the internal combustion engine main body. In the cooling device of the formed water-cooled internal combustion engine, the radiator mounting surface of the internal combustion engine main body is provided apart from an outer wall surface of a component having a cooling water jacket of the internal combustion engine main body, and the radiator and the outer wall surface are provided. A cooling device for a water-cooled internal combustion engine, wherein a heat insulating space is formed between the cooling device and the cooling device. 2. The radiator mounting surface of the internal combustion engine main body is formed integrally with a component of the internal combustion engine main body having the radiator mounting surface.
A cooling device for a water-cooled internal combustion engine according to claim 1.