Patent Grant
8225751
The present invention relates generally to a cooling water passage structure for an engine, and particularly for an engine mounted on a motorcycle.
In related art, there is known a cooling water passage structure for an engine as below. This structure includes cylinders arranged in a V-shape and a cylinder block having a water jacket surrounding the cylinders. A thermostat chamber is concavely provided in a valley portion in the upper surface of the cylinder block. An impeller chamber of a water pump is concavely provided at an end face of the cylinder block. A suction water passage connecting a bottom of the thermostat chamber with the impeller chamber, a cooling water passage connecting a water pump outlet with the water jacket, and a bypass hole communicating from the thermostat chamber to the outside are provided inside the wall body of the cylinder block. A warm water tube communicating from the water jacket to a radiator and a cooling water tube communicating from the radiator to the thermostat chamber are provided outside the cylinder head. (See e.g. Japanese Utility Model Laid-open No. Hei 2-139325.)
Incidentally, in the engine cooling water passage structure described in Japanese Utility Model Laid-open No. Hei 2-139325, the thermostat case is formed within the V-bank of the cylinder block. Since the cooling water line is complicatedly arranged to extend in the narrow space within the V-bank, it is difficult to improve the productivity of the engine. It is needed to simplify the cooling water passage structure.
In view of the foregoing, it is an object of the present invention to provide a cooling water passage structure for an engine that can be simplified and improve the productivity of the engine.
To achieve the above problem, a first aspect of the invention is a cooling water passage structure for an engine, including: an engine having cylinder axes arranged in a V-shape centering on a crankshaft; water jackets formed in respective cylinder blocks and respective cylinder heads of the engine; a thermostat case having a portion formed integrally with the cylinder blocks in the V-bank of the cylinder blocks; a cooling water inlet side connecting portion connecting a cooling water supply side line with a cooling water passage including the water jackets; and a cooling water outlet side connecting portion connecting a cooling water discharge side line with a cooling water passage including the water jackets; and characterized in that the thermostat case, the cooling water inlet side connecting portion, and the cooling water outlet side connecting portion are disposed on one side of the engine in the axial direction of the crankshaft.
A second aspect of the invention is characterized in that, in addition to the configuration of the first aspect of the invention, the cooling water inlet side connecting portion and the cooling water outlet side connecting portion are arranged on a centerline to align with each other as viewed from the axial direction of the crankshaft, the centerline dividing the V-bank of the cylinder blocks in two.
A third aspect of the invention is characterized by, in addition to the configuration of the first aspect of the invention, further including a cooling water discharge passage adapted to discharge cooling water from the water jackets to the thermostat case and characterized in that the cooling water discharge passage is formed in the cylinder heads to extend in a direction perpendicular to the crankshaft; and characterized in that the cooling water discharge passage and the thermostat case are arranged in a direction perpendicular to the crankshaft so as to align with each other.
A fourth aspect of the invention is characterized by, in addition to the configuration of the invention recited in claim 1, further including a bypass line connected to an end of the thermostat case opposite the crankshaft with respect to the thermostat case and characterized in that the bypass line extends toward one side of the engine in the direction of the crankshaft, and connects with a water pump.
A fifth aspect of the invention is characterized by, in addition to the configuration of the first aspect of the invention, further including a cooling water supply passage adapted to supply cooling water from the cooling water inlet side connecting portion to the water jackets, and characterized in that the cooling water supply passage is forms a protrusion on the cylinder block, and the protrusion includes an engine hanger used to secure the engine to a body frame.
A sixth aspect of the invention is characterized in that, in addition to the configuration of the first aspect of the invention, the cooling water discharge passage is formed in a V-shape as viewed from the direction of the crankshaft and the thermostat case is disposed at a central portion of the V-shape, a temperature sensor constituting a thermostat is disposed in the V-bank formed by the cooling water discharge passage, a bypass passage connecting portion is formed on the downstream side of the temperature sensor, and the cooling water discharge side connecting portion is formed in the vicinity of the top of the V-bank formed by the cooling water discharge passage.
According to the cooling water passage structure for an engine according to the first aspect of the invention, the thermostat case, the cooling water inlet side connecting portion, and the cooling water outlet side connecting portion are disposed on one side of the engine in the axial direction of the crankshaft. The cooling water line is not arranged to extend in the narrow space in the V-bank. Thus, the cooling water passage structure can be simplified to improve the productivity of the engine. In addition, the space for arranging auxiliary devices therein can be ensured in the V-bank.
According to the cooling water passage structure for an engine according to the second aspect of the invention, the cooling water inlet side connecting portion and the cooling water outlet side connecting portion are arranged on a centerline to align with each other as viewed from the axial direction of the crankshaft, the centerline dividing the V-bank of the cylinder blocks in two. Thus, the V-bank shape of the cylinder block can effectively be utilized to make the engine compact.
According to the cooling water passage structure for an engine according to the third aspect of the invention, a cooling water discharge passage adapted to discharge cooling water from the water jackets to the thermostat case is provided and the cooling water discharge passage is formed in the cylinder heads to extend in a direction perpendicular to the crankshaft, and the cooling water discharge passage and the thermostat case are arranged in a direction perpendicular to the crankshaft so as to align with each other. The partition wall between the cooling water discharge passage and the thermostat case can be shared with each other. Thus, the thickness of the partition wall can be reduced compared with the case where the partition wall is formed individually, thereby reducing the weight of the engine. In addition, the cooling water discharge passage and the thermostat case are formed to connect the V-arranged cylinder blocks and the thermostat case with each other in the back and forth direction of the vehicle. Thus, the rigidity of the cylinder blocks can be improved.
According to the cooling water passage structure for an engine according to the fourth aspect of the invention, the bypass line is provided which is connected to an end of the thermostat case opposite from the crankshaft with respect to the thermostat case, and the bypass line extends toward one side of the engine in the axial direction of the crankshaft and connects with a water pump. Thus, all the cooling water lines can be put together on one side of the engine, so that it is easy to check the cooling water lines. In addition, the space in the V-bank can be ensured.
According to the cooling water passage structure for an engine according to the fifth aspect of the invention, the cooling water supply passage is provided which is adapted to supply cooling water from the cooling water inlet side connecting portion to the water jackets, the cooling water supply passage is forms the protrusion on the cylinder block, and the protrusion includes an engine hanger used to secure the engine to a body frame. Thus, the protrusion is effectively be utilized to form the engine hanger, thereby reducing the size of the engine.
According to the cooling water passage structure for an engine according to the sixth aspect of the invention, during warm-up operation, the cooling water flowing toward the bypass line flows through the temperature sensor and the temperature sensor is disposed near a position where the direction of the flow of the cooling water from the water jackets is changed. Thus, the temperature of the cooling water can efficiently be transmitted to the temperature sensor, thereby enhancing the response of the temperature. At the time of completing the warm-up operation, the cooling water increased in flow rate after the warm-up operation can be led to the cooling water outlet side connecting portion in the form conforming to the direction of the flow thereof because the cooling water outlet side connecting portion is formed in the vicinity of the top of the V-bank formed by the cooling water discharge passages. Thus, pressure loss can be reduced to improve the efficiency of the water pump.
The advantages of the invention will become apparent in the following description taken in conjunction with the drawings, wherein:
An embodiment of a cooling water passage structure for an engine according to the present invention will hereinafter be described in detail with reference to the accompanying drawings. It is to be noted that the drawings shall be viewed based on the orientation of referential symbols.
In the following description the front and back or rear, the left and right, the upside and downside are based on the direction a rider looks and the front is indicated with Fr, the rear Rr, the left side L, the right side R, the upside U and the downside D.
With reference to
In
The rear suspension 40 includes a suspension unit 41 swingably mounted to the rear portion of the main frames 12; a generally triangular first link 42 swingably connecting the lower end of the suspension unit 41 with the lower intermediate portion of the swing arm 15; and a second link 43 swingably connecting the first link 42 with the rear portion of the engine 50.
The engine 50 is a water-cooled V-type 4-cylinder engine and as shown in
With reference to
With reference to
The thermostat valve 73 includes a wax case 73a which is a temperature sensor; a plunger 73b inserted through the wax case 73a; a first valve body 73c formed at the upper end of the plunger 73b; and a second valve body 73d formed at the lower end of the plunger 73b.
As shown in
As shown in
As shown in
In the present embodiment, the thermostat case 71 (the thermostat 70), the cooling water inlet side connecting portion 81 and the cooling water outlet side connecting portion 82 are arranged on one side (on the left side in the embodiment) in the direction of the crankshaft 52 of the engine 50.
As shown in
As shown in
In the present embodiment, one end of the bypass pipe 68 is connected to one end of the thermostat case 71 on the side separate from the crankshaft 52, i.e., to the upper end of the lid portion 75 of the thermostat case 71. The other end of the bypass pipe 68 extends toward the one end side (on the left end side in the present embodiment) of the engine 50 in the direction of the crankshaft 52 and is connected to the water pump 61.
As shown in
As shown in
As shown in
As shown in
In the present embodiment, as shown in
In the engine cooling water passage structure configured as above, as shown in
In this way, during warm-up operation, since the first valve body 73c of the thermostat valve 73 is opened and the second valve body 73d is closed (see the solid lines in
As described above, according to the engine cooling water passage structure of the present embodiment, the thermostat case 71, the cooling water inlet side connecting portion 81 and the cooling water outlet side connecting portion 82 are disposed on one side of the engine 50 in the direction of the crankshaft 52. Therefore, the cooling water line is not arranged to extend in the narrow space within the V-bank. Thus, the cooling water passage structure can be simplified to enhance the productivity of the engine. In addition, a space adapted to arrange auxiliary machines therein can be ensured in the V-bank.
According to the engine cooling water passage structure, the cooling water inlet side connecting portion 81 and the cooling water outlet side connecting portion 82 are arranged to align with each other on the centerline CL as viewed from the direction of the crankshaft 52, the centerline CL dividing the V-bank of the front and rear cylinder blocks 53F, 53R in two. The V-bank shape of the front and rear cylinder blocks 53F, 53R can effectively be utilized. Thus, the engine 50 can be made compact.
The engine cooling water passage structure of the present embodiment is provided with the cooling water discharge passages 84, 84 each adapted to discharge cooling water from a corresponding one of the water jackets 62, 63 to the thermostat case 71. The cooling water discharge passages 84, 84 are each formed in a corresponding one of the front and rear cylinder blocks 53F, 53R so as to extend along the direction perpendicular to the crankshaft 52. The cooling water discharge passages 84, 84 and the thermostat case 71 are arranged to align with each other in the direction perpendicular to the crankshaft 52. The partition wall between one of the cooling water discharge passages 84, 84 and the thermostat case 71 and between the other cooling water discharge passage and the thermostat case 71 can be shared with each other. Thus, the thickness of the partition wall can be reduced compared with the case where the partition wall is individually formed, thereby reducing the weight of the engine 50. In addition, the cooling water discharge passages 84, 84 and the thermostat case 71 are formed to connect the V-arranged front and rear cylinder blocks 53F, 53R with each other in the back and forth direction of the vehicle. Thus, the rigidity of the front and rear cylinder blocks 53F, 53R can be increased.
According to the engine cooling water passage structure of the present embodiment is provided with the bypass line 68 connected to the end of the thermostat case 71 on the side separate from the crankshaft 52. The bypass line 68 extends toward one end of the engine 50 in the direction of the crankshaft 52 and connects with the water pump 61. All the cooling water lines 65, 66, 67, 68 can be put together on one side of the engine 50. Thus, the cooling lines 65, 66, 67, 68 can easily be checked. In addition, the space within the V-bank can be ensured.
The engine cooling water passage structure of the present embodiment is provided with the cooling water supply passages 83, 83 adapted to supply cooling water from the cooling water inlet side connecting portion 81 to the water jackets 62, 63. The cooling water supply passage 83 is provided to form the protrusion 57 on the front cylinder block 53F. The protrusion 57 is formed with the engine hanger 58 used to secure the engine 50 to the main frames 12. Thus, the protrusion 57 can effectively be utilized to form the engine hanger 58, thereby reducing the weight of the engine 50.
According to the engine cooling water passage structure of the present embodiment, during warm-up operation, the cooling water flowing toward the bypass line flows through the wax case 73a, and the wax case 73a is disposed near a position where the direction of the flow of the cooling water from the water jackets 62, 63 is changed. Thus, the temperature of the cooling water can efficiently be transmitted to the wax case 73a, thereby enhancing the response of the wax case 73a. At the time of completing the warm-up operation, the cooling water increased in flow rate after the warm-up operation can be led to the cooling water outlet side connecting portion 82 in the form conforming to the direction of the flow thereof, because the cooling water outlet side connecting portion 82 is formed in the vicinity of the top of the V-bank formed by the cooling water discharge passages 84, 84. Thus, pressure loss is reduced to improve the efficiency of the water pump 61.
Although a specific form of embodiment of the instant invention has been described above and illustrated in the accompanying drawings in order to be more clearly understood, the above description is made by way of example and not as a limitation to the scope of the instant invention. It is contemplated that various modifications apparent to one of ordinary skill in the art could be made without departing from the scope of the invention which is to be determined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-322380 | Dec 2007 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 2871836 | Doughty | Feb 1959 | A |
| 5111774 | Hiramoto et al. | May 1992 | A |
| 5131357 | Inoue et al. | Jul 1992 | A |
| 5279265 | Matsuo et al. | Jan 1994 | A |
| 6125811 | Koriyama et al. | Oct 2000 | A |
| 6843209 | Miyagawa et al. | Jan 2005 | B2 |
| 6978742 | Miyagawa et al. | Dec 2005 | B2 |
| 20020195289 | Schneider et al. | Dec 2002 | A1 |
| Number | Date | Country |
|---|---|---|
| 0 933 510 | Aug 1999 | EP |
| 2 249 347 | May 1992 | GB |
| 2-139325 | Nov 1990 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20090151662 A1 | Jun 2009 | US |
