Title of Invention

"A COOLING APPARATUS FOR A WATER-COOLED INTERNAL COMBUSTION ENGINE"

Abstract

[Problem] In a cooling apparatus for a water-cooled internal combustion engine, a cooling water pump, a cooling water jacket, and a radiator are arranged in close proximity to each other, to thereby shorten the length of a cooling water passage, reduce resistance in the passage, minimize the size of the cooling water pump, and decrease the number of parts used in the apparatus. [Solving Means] A cooling water pump 50 is mounted on a cylinder 4 or a cylinder head section (a cylinder head 5 and a cylinder head cover 6) of an internal combustion engine for supplying cooling water under pressure to cooling water jackets 44, 45 disposed on the cylinder 4 or the cylinder head 5 of the engine. A radiator 30 is positioned within a height range determined by the cooling water pump 50 located on an axis line of the cylinder and the cooling jackets 44, 45. Also, the radiator 30 is directly mounted on the cylinder 4 or the cylinder head section of the engine.

Full Text

[0001] [Technical Field of the Invention] , The present invention relates generally to a cooling appua for a water-cooled internal combustion engine having a relatively small displacement, such as a combustion engine for a small vehicle including a motorcycle . More particularly, the present invention relates to a cooling system for a water-cooled internal combustion engine having an improved positional adjustment of a cooling water pump, a cooling water jacket mounted on a cylinder or a cylinder head section, and a radiator. [Related Art] In a conventional cooling system for such a water-cooled internal combustion engine, a radiator is located opposite to a crank outside an area whose height is determined by the cooling water pump and the cooling water jacket disposed on the axis line of the cylinder (see Japanese Utility Model Laid-Open Application No. Hei 6-48099). [0003] [Problem to be Solved by the Invention] Such a conventional cooling system requires a long and complicated water passage in which the water flow must turn many times, resulting in the increased resistance in the passage. In order to decrease such resistance, a large sized cooling water pump having a large capacity must be used. [0004] [Means for Solving the Problem and Advantage Thereof] The present invention is directed to an improvement to the cooling system for a water-cooled internal combustion engine for solving the above problem. According to claim 1 of the present invention, there is provided a cooling apparatus for a water-cooled internal combustion engine in which a cooling water pump is mounted on a cylinder or a cylinder head section of the internal combustion engine for supplying the cooling water under pressure to a cooling water jacket, and a radiator is positioned within a height range determined by the cooling water pump and the cooling jacket disposed on the axis line of the cylinder [0005] With such an arrangement, the invention according to claim 1 enables the cooling water pump, the cooling water jacket mounted on the cylinder or the cylinder head, and the radiator, to be located in relatively close proximity to each other. Accordingly, the water passage can be shortened and less complicated, decreasing the resistance in the passage and reducing the capacity and the size of the cooling water pump. [0006] Also, the shortened and less complicated water passage allows the number of parts used in the passage, such as pipes, hoses, and bands, to be reduced. [0007] According to claim 2, the above advantage of the present invention achieved by the structure as defined in claim I may be enhanced [0008] When implemented in the structure as defined in claim 3, the present invention according to claim 2 presents another advantage that the cooling water in the radiator can be cooled efficiently, because air blows from the front to the rear of the vehicle and strikes forcibly on the radiator at a high speed. In addition, the cylinder block is located below the radiator to protect it from being damaged by stones scattering as the vehicle travels. Accordingly, the present invention relates to a cooling apparatus for a water-cooled internal combustion engine -Characterised in that a cooling water pump mounted on a cylinder or a cylinder head section for pumping cooling water under pressure to a cooling water jackets disposed on the cylinder or the cylinder head of the internal combustion engine and a radiator positioned in a height range determined by the cooling water pump arranged on an axis line of the cylinder and the cooling water jackets. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Fig, 1 is a perspective view schematically showing a water-cooled internal combustion engine incorporating a cooling apparatus according to one embodiment (Embodiment 1) of the present invention as defined in claims 1 to 3; Fig, 2 is a side view showing the right side of the apparatus of Fig. 1; Fig, 3 is a plan view along line Ill-Ill of Fig. 2 when placed in the portrait orientation; Fig, 4 is a partially enlarged view of Fig. 3; Fig, 5 is a partially cut away view showing the front side of the apparatus of Fig. 2 when seen from a direction indicated by an arrow V; Fig. 6 is a partially cut away view showing the left side of the apparatus of Fig. 1; Fig. 7 is a plan view showing a cooling apparatus according to another embodiment (Embodiment 2) of the present invention as defined in claims 1 to 3 when placed in the portrait orientation; and Fig. 8 is a partially cut away view showing the left side of the apparatus of Fig. 7, including two partial sections of a cooling water pump at the impeller position and the magnet coupling position. [0009] [Mode for Carrying Out the Invention] In the following, one embodiment (Embodiment 1) of the present invention according to claims 1 to 3 will be described with reference to Figs. 1 to 6. Fig. 1 is a perspective view schematically showing a water-cooled internal combustion engine incorporating a cooling apparatus for the water-cooled internal combustion engine of Embodiment 1. A water-cooled internal combustion engine 1 is an overhead cam shaft type four stroke cycle (commonly known as a four-cycle) single cylinder engine a/prd—i-a,.mounted on the body of a small motorcycle, which is not shown, between its front and rear wheels. [0010] The water-cooled internal combustion engine 1 includes right and left portions 2, 3 of a crank case, a cylinder block (cylinder) 4, a cylinder head 5, and a cylinder head cover 6. The cylinder block 4 is disposed on the front end of the crank case portions 2, 3, so that the central axis line of a cylinder hole 7 off the cylinder block 4 extends forward in a generally horizontal direction. Then, the cylinder head section consisting of the cylinder head 5 and the cylinder head cover 6 are mounted in this order on the front side of the cylinder block 4 . The crank case portions 2, 3, the cylinder block 4, the cylinder head 5, and the cylinder head cover 6 are integrally connected with each other. [0011] An attaching surface (or a split face) 65 of the cylinder head cover 6 attaching to the cylinder head 5 is positioned lower than another attaching surface (a split face) 66 formed at a. position attaching to a cam shaft 18 described below, as shown in Figs. 3 and 4. The cylinder head cover 6 is integrally coupled with the cylinder head 5 with a plurality of bolts 67 provided radially on the attaching surface 65. [0012] In this way, the axis line of the cam shaft 18 penetrates through both side walls of the cylinder head cover 6. As shown in the figure of the cylinder head cover 6, there is a hole 68 for attaching a cooling water pump 50 described below in the left side wall of the cylinder head cover 6 at a point where the axis line of the cam shaft 18 penetrates, so that an outer surface 69 of the left side wall acts as an attaching surface of the cooling water pump 50. [0013] As shown in Figs. 3 and 4, a piston 8 is slidably fitted into a cylinder hole 7, a crankshaft 9 is pivotally fitted to the right and left portions 2,3 of the crank case, and each end of a connecting rod 12 is pivotally fitted to the piston 8 and the crankshaft 9, respectively, by means of a piston pin 10 and a crank pin 11. Thus, the crankshaft 9 is rotated by the reciprocating movement of the piston 8. [0014] The cylinder head 5 has an inlet port 14 and an exhaust port 15, each communicating with a combustion chamber 13 located at the top of the cylinder hole 7. The inlet port 14 and the exhaust port 15 include an inlet valve 16 and an exhaust valve 17, respectively, which can open and close as needed. [0015] The cam shaft 18 is located in the upper part of the cylinder head 5 adjacent to the upper end of the inlet valve 16 and the exhaust valve 17, and is pivotally mounted between the cylinder head 5 and a cam shaft holder 20 via a bearing 19. A driven sprocket 21 is integrally fitted with an enlarged diameter section 18a of the left end of the cam shaft 18, and an endless chain 23 is laid between a driving sprocket 22 formed integrally with the crankshaft 9 and the driven sprocket 21. The cam shaft 18 is driven to rotate at half the rotating speed of the crankshaft 9, enabling the inlet valve 16 and the exhaust valve 17 to open and close once as the crankshaft 9 rotates twice. [0016] As shown in Figs. 2, 5, and 6, a radiator 30 is located above the cylinder block 4 for radiating heat of the cooling apparatus for the water-cooled internal combustion engine I. The radiator 30 includes left and right cooling water tanks 31, 32 (note that the tank 31 is shown on the right and the tank 32 is shown on the left of Fig. 5) , a plurality of planar radiating fins 33 normally disposed in parallel and extending forward and rearward of the vehicle, and cooling water conduits 34 having a circular section and horizontally penetrating through the radiating fins 33 and the opposite inner walls of the cooling water tanks 31, 32 (for example, three conduits arranged in upper and lower rows, and two or three conduits arranged horizontally). A cooling water' inlet/outlet opening 35 is formed in a bottom surface 31a of the cooling water tanks 31, 32 (only the bottom surface of the cooling water tank 31 is shown in Fig. 6) , into which a connecting sleeve 38 is fitted extending downwards. [0017] Also, the radiator 30 is securely fixed to the cylinder block 4 with bolts 47 which penetrate through flanges 36, 36 formed integrally with the bottom of the cooling water tanks 31, 32 and are screwed into radiator supporting sections 40, 41 described below. Further, a cap 39 is removably mounted on top of the cooling water tank 31. [0018] As shown in Figs. 3 and 4, the radiator supporting sections 40, 41 are formed integrally with and extending to the right and the left of the cylinder block 4, and include cooling water passages 42, 43. The right water passage 43 communicates with a cylindrical cooling water jacket 44 surrounding the outer periphery of the combustion chamber 13, while another cooling water jacket 45 matching to the opening end of the jacket 44 is mounted on the cylinder head 5. Both cooling water jackets 44, 45 are tapered so that their sections become smaller as the jackets extend inwardly from an interface between the cylinder block 4 and the cylinder head 5. The lower end of the connecting sleeve 38 is fitted into the upper opening of the left water passage 42, so that it communicates with the cooling water tank 32 via the sleeve 38. [0019] As can be understood from the above description referring to Figs. 3 and 4, the radiator 30 is positioned on the central axis line of the cylinder hole 7 of the cylinder block 4 and within a height range determined by the cooling water pump 50 and the cooling water jackets 45, 44 which are arranged in close proximity to each other. [0020] Also, as shown in Figs. 3 and 4, a recess 18b is formed in the enlarged diameter section 18a at the left end of the cam shaft 18 by removing the center part of the end section, and a plurality of permanent magnets 24 are provided spaced equal distances apart from each other on the inner periphery of the recess 18b. [0021] The cooling water pump 50 is driven by the rotation of the cam shaft 18 and includes a bulkhead (a pump casing) 51, a pump cover 52, and an impeller 54 which is rotatably mounted on the bulkhead 51 and the pump cover 52 via a supporting shaft 53 in a rotor accommodating section 51a of the bulkhead 51. The impeller 54 is provided with a plurality of permanent magnets 55 formed around the outer periphery of its axis 54a via the rotor accommodating section 51a of the bulkhead 51, these permanent magnets 55 corresponding to the permanent magnets 24 of the cam shaft 18 . These permanent magnets 55, 24 together form a magnetic coupling to magnetically connect the axis 54a of the impeller 54 of the cooling water pump 50 to the cam shaft 18, whereby the impeller 54 can be rotated in response to the rotation of the cam shaft 18. [0022] The bulkhead (the bulkhead of the magnetic coupling) 51 of the cooling water pump 50 is formed by a resin material, such as PPS. The bulkhead 51 is sandwiched between the left side wall of the cylinder head cover 6 and the pump cover 52 by fitting the base end having a large diameter section of the rotor accommodating section 51a into a pump attaching hole 68 formed in the left side wall of the cylinder head cover 6. [0023] As show in Fig. 6, a water inlet section 56 of the cooling water pump 50 is in communication with a lower opening 42a of the cooling water passage 42 via a communicating pipe 46 in the left radiator supporting section 40. As shown in Fig. 4, a water discharging section 57 of the cooling water pump 50 is in communication with a water discharging passage 58 (formed in a closed position by the bulkhead 51) of the pump cover 52. Each end of a communicating pipe 61 is connected in a watertight manner to a communicating path 59 of the bulkhead 51 communicating with the water discharging passage 58 and a communicating passage 60 communicating with the cooling water jacket 45 of the cylinder head 5. The cooling water in the left cooling water tank 31 of the radiator 30 is drawn into the cooling water pump 50 via the cooling water passage 42 of the left radiator supporting section 40, the communicating pipe 46, and the water inlet section 46, and is pressurized to pass through the water discharging section 57 and flow into the cooling water jackets 44, 45 via the water discharging passage 58, the communicating path 59, and the communicating pipes 61, 60. [0024] On the communicating path 59 side of Embodiment 1, the communicating pipe 61 is fitted into a hole 63 formed in the outer side wall of the cylinder head 5 surrounding a transmission mechanism chamber 62, which further ensures the watertight attachment of the communicating pipe 61. Alternatively, the communicating pipe 61 may be formed integrally with the bulkhead 51 of the cooling water pump 50. [0025] Further, as shown in Figs. 3 and 4, an idler sprocket (an idle pulley) 25 is rotatably mounted on the outer periphery of the communicating pipe 61 and meshes with an endless chain 23, while an idler sprocket 27 is pivotally mounted on the cylinder block 4 via a pin 26 at a position closer to the crankshaft 9 side than the idler sprocket 25. In the vicinity of the crankshaft 9, idler sprockets 28, 29 are arranged so as to sandwich the endless chain 23 from the upper and the lower sides thereof, as can be seen from Fig. 6. [0026] Referring to Fig. 6, since the communicating pipe 61 is located inside an area surrounded by the running path of the chain 23 accommodated in the transmission mechanism chamber 62, the idler sprocket 25 which is mounted around the outer periphery of the communicating pipe 61 is also located in the same area. Thus, the idler sprocket 25 meshes with the inner surface of the endless chain 23. [0027] With such a structure, Embodiment 1 of the present invention presents the following advantages and utilities. When the water-cooled internal combustion engine 1 is started and the impeller 54 of the cooling water pump 50, which is magnetically connected to the cam shaft 18 so as to rotate in response to the operation of the engine 1, starts to rotate, the cooling water in the left cooling water tank 31 cooled by the radiator 30 is sucked via the cooling water inlet/outlet opening 35 to pass through the connecting sleeve 38, the cooling water passage 42 of the radiator supporting section 40, and the connecting pipe 46 and then flows into the inlet section 56 of the cooling water pump 50. After being pressurized by the impeller 54 of the cooling water pump 50, the cooling water is discharged from the outlet section 57 of the pump 50 to pass through the discharging passage 58 and the communicating paths 59; '61, and 60 to flow into the cooling water jackets 45, 44. The cooling water then flows from the jackets 45, 44 to pass through the cooling water passage 43 of the right radiator supporting section 41 into the right cooling water tank 32, and then returns to the left cooling water tank 31 through the cooling water conduits 34. In this way, the cooling water circulates in the cooling water system. [0028] In response to the movement of a small-sized motorcycle, which is not shown, air blows from the front to the rear of the motorcycle to pass through the heat radiating fins 33 of the radiator 30, cooling the heat radiating fins 33 heated by the water flowing within the cooling water conduits 34. The water in the cooling water conduits 34 is, in turn, cooled by heat radiation of the fins 33. Since the heat radiating fins 33 are arranged in upper and lower rows, heat can be radiated efficiently by means of natural convection of air when the motorcycle is stopped. [0029] The radiator 30 is located on the axis line of the cylinder in a height range determined by the cooling water pump 50 and the cooling water jackets 45, 44, and is directly attached to the cylinder block at the radiator supporting sections 40, 41. Thus, the cooling water pump 50, the cooling water jackets 44, 45 formed on the cylinder block 4 and the cylinder head 5, and the radiator 30 are arranged in relatively close proximity to each other, which allows the water passage to be shortened and less complicated, reducing the resistance in the passage. As a result, the capacity and the size of the cooling water pump 50 can be decreased. Also, the number of parts used in the passage, such as pipes, hoses, and bands, can be reduced in such a shortened and less complicated cooling water passage. [0030] Since the central axis line of the cylinder hole 7 of the cylinder block 4 is directed forward in a generally horizontal direction, and the radiator 30 is directly attached on the cylinder block 4, the air blowing from the front strikes on the radiator 30 at a high speed to effectively deprive the cooling water in the radiator 30 of heat. Further, the cylinder block 4 is arranged below the radiator 30 so that it is protected from being damaged by small stones scattered by the movement of the vehicle. [0031] With reference to Figs. 7 and 8, an alternative embodiment (Embodiment 2) of the invention according to claims 1 and 3 will be described. In these figures, the same reference numbers are given to the elements corresponding to those of Embodiment 1. In Embodiment 2, the cooling water pump 50 of Embodiment 1 is moved up to the level of the combustion chamber 13 of a cylinder block 70 described below and indicated as a cooling water pump 80. [0032] With reference to Fig. 7 illustrating the cylinder and the cylinder head of the cylinder block 70, the cooling water pump 80 is attached at a large diameter section of its bulkhead (pump casing) 81 to a pump attaching hole 71 formed in the left side wall in a watertight manner and the bottom of the bulkhead 81 having a small diameter is supported by the side wall of a cover 72 covering the left side of the cylinder block 70. [0033] The pump attaching hole 71 extends above and below the combustion chamber 13 and is formed adjacent to the cylinder chamber and the exhaust port 15. Thus, the pump attaching position for the cooling water pump 80 vertically runs across' the position where a cooling water jacket 73 is formed. [0034] A space between the cylinder block 70 and the cover 72 serves as a transmission mechanism chamber 62 which accommodates the endless chain 23. A driven sprocket 83 with permanent magnets rotatably arranged around a small diameter section of the bulkhead 81 of the cooling water pump 80 is rotated by the operation of the endless chain 23. In response to the rotation of the driven sprocket 83, a shaft section 85a of an impeller 85 of the magnetic coupling type cooling water pump 80 starts to rotate. The driven sprocket 83 is rotatably supported on a bearing section of the cover 72 via a bearing 84. A reference numeral 82 indicates a supporting shaft of the cooling water pump 80 into which the shaft section 85a of the impeller 85 is rotatably inserted. [0035] As in a conventional internal combustion engine, the cylinder block 70 consists of a cylinder, a cylinder head, and a cylinder cover which are formed integrally. In the upper part of the block corresponding to the cylinder head cover, two larger and smaller bearing holes 74, 75 are formed to rotatably support the cam shaft 18 via the bearing 19, and the assembly of the cam shaft 18 is inserted into these holes from the left side of the cover and securely fixed to the cylinder block 70 with fixture 76, as shown in Fig. 7. The driven sprocket 21, which is rotated by the endless chain 23, is mounted integrally with the left end of the cam shaft 18. [0036] Although not shown in detail, the right side of the cylinder block 70 is partially covered by a cover 77 whose fin forming section 77a is recessed to form a portion of a side wall of the cooling water jacket 73. The cover 77 also includes an inlet channel 14a which is in communication with the inlet port 14. [0037] In Embodiment 2, a radiator 90 includes upper and lower tanks 92, 91 which are connected together by a plurality of cooling water conduits 94. A plurality of planar heat radiating fins 93 are layered and attached to these conduits 94 which penetrate through the fins 93. [0038] The upper tank 92 is in fluidic communication with a discharging channel 86 of the cooling water pump 80 via a communicating pipe 96, while the lower tank 91 is in fluidic communication with the cooling water jacket opposite the discharging channel 86 via a communicating pipe which is not shown. The radiator 90 is fixed to the cylinder block 70 securely and directly at its flange section 95 with bolts 47 screwed into the flange at two points in the front and the rear and at another two points in the left and the right. [0039] Once the water-cooled internal combustion engine 1 is operated, the driven sprocket 83 is rotated by the endless chain 23 which starts moving in response to the operation of the engine 1, initiating the rotation of the shaft section 85a of the impeller 85 of the cooling water pump 80, which is magnetically connected to the sprocket 83, to rotate the impeller 85. Accordingly, the water heated by the cooling water jacket 73 is sucked by the cooling water pump 80 and is pressurized to flow through the discharging channel 86 and the communicating pipe 96 into the upper tank 92. [0040] The cooling water flows into the upper tank 92 through the plurality of cooling water conduits 94 and is cooled effectively by the air blowing through the heat radiating fins 93 before flowing into the lower tank 91. The cooling water flows into the lower tank 91 then returns to the cooling water jacket 73 via a communicating pipe which is not shown, thus completing its circulation through the cooling water system. Other portions of Embodiment 2 are generally similar to those of Embodiment 1, so no more detailed description will be given herein. [0041] With the structure described above, the radiator 90 of Embodiment 2 is placed on the axis line of the cylinder within a height range determined by the cooling water pump 80 and the cooling water jacket 73 which are arranged or formed at the same height. Thus, the cooling water pump 80, the cooling water j acket 73, and the radiator 90 of this embodiment are arranged closer to each other than in Embodiment 1. As a result, the length of the cooling water passage (consisting of the pump discharging channel 86, the communicating pipe 96, and other communicating pipes and pump inlet channels which are not shown) can be shortened and made less complicated to significantly decrease the resistance of the passage. Thus, the cooling water pump having a reduced capacity and size can be obtained. [0042] Further, as the cooling water passage becomes very short and less complicated, the number of parts used in the passage, such as pipes, hoses, and bands, can be reduced. Embodiment 2 also provides other advantages similar to those accomplished by Embodiment 1. [Description of Reference Numerals] 1: water-cooled internal combustion engine 2,3: crank case cylinder block (cylinder) cylinder head cylinder head cover cylinder hole piston crankshaft 9 10: piston pin 11: crank pin 12: connecting rod 13: combustion chamber 14 : inlet port 14a: inlet channel 15: exhaust port 16: inlet valve 17: exhaust valve 18: cam shaft 18a: enlarged diameter section 18b: recess 19: bearing 20: cam shaft holder 21: driven sprocket 22: driving sprocket 23: endless chain 24: permanent magnet 25: idler sprocket 26: pin 27, 28, 29: idler sprocket 30: radiator 31,32: cooling water tank 33: heat radiating fin 34 : cooling water conduit 35: cooling water inlet/outlet opening 36: flange 38: connecting sleeve 39: cap 40,41: radiator supporting section 42,43: cooling water passage 46 47 50 51 52 53 54 44,45: cooling water jacket communicating pipe bolt magnet coupling type cooling water pump bulkhead (pump casing) pump cover supporting shaft impeller 54a: shaft section 55: permanent magnet 56: inlet section 57: discharging section 58: discharging passage 59,60: communicating path 61: communicating pipe 62: transmission mechanism chamber 63: hole 65: attaching surface (split face of cylinder head cover) 66: attaching surface (split face) 67: bolt 68: pump attaching hole 69: outer side wall of cylinder head cover (pump attaching surface) 70: cylinder block 71: pump attaching hole 72: cover 73: cooling water jacket 74,75: bearing hole 76: fixture 77: cover 77a: fin forming section 80: cooling water pump 81: bulkhead (pump casing) 82: supporting shaft 83: driven sprocket 84 : bearing 85: impeller 85a: shaft section 86: pump discharging channel 90: radiator 91: lower tank 92: upper tank 93: heat radiating fin 94: cooling water conduit 95: flange section 96: communicating pipe We claim: 1. A cooling apparatus for a water-cooled internal combustion engine (1) Characterized in that a cooling water pump (50) mounted on a cylinder (4) or a cylinder head section for pumping cooling water under pressure to a cooling water jackets (44, 45) disposed on the cylinder or the cylinder head of the internal combustion engine (1); and a radiator (30) positioned in a height range determined by the cooling water pump (50) arranged on an axis line of the cylinder and the cooling water jackets (44, 45). 2. A cooling apparatus for a water-cooled internal combustion engine (1) as claimed in claim 1, wherein the radiator (30) is directly attached to the cylinder (4) or the cylinder head section. 3. A cooling apparatus for a water-cooled combustion engine as claimed in claim 2, wherein the cylinder (4) is arranged in a horizontal direction, and the radiator (30) is directly mounted on the cylinder (4). 4. A cooling apparatus for a water-cooled internal combustion engine substantially as herein described with reference to the accompanying drawings.

Documents:

2530-del-1998-abstract.pdf

2530-del-1998-claims.pdf

2530-del-1998-correspondence-others.pdf

2530-del-1998-correspondence-po.pdf

2530-del-1998-description (complete).pdf

2530-del-1998-drawings.pdf

2530-del-1998-form-1.pdf

2530-del-1998-form-13.pdf

2530-del-1998-form-19.pdf

2530-del-1998-form-2.pdf

2530-del-1998-form-3.pdf

2530-del-1998-form-4.pdf

2530-del-1998-form-6.pdf

2530-del-1998-gpa.pdf

2530-del-1998-petition-137.pdf

2530-del-1998-petition-138.pdf

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