JP3894702B2 - Cooling water temperature stabilization device for water-cooled engine for vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for stabilizing the temperature of cooling water in a vehicle water-cooled engine in which a water jacket for circulating cooling water to and from a radiator is provided in an engine body.
[0002]
[Prior art]
Conventionally, in such a water-cooled engine, as disclosed in, for example, Japanese Patent Laid-Open No. 3-64621, the temperature of cooling water in a radiator is detected, and an electric fan is rotated according to the detection result, thereby cooling the engine. It prevents the water temperature from rising.
[0003]
[Problems to be solved by the invention]
By the way, if the temperature of the cooling water in the cooling water circulation circuit between the radiator and the water jacket rises due to the malfunction of the electric fan etc. and the amount of evaporation from the radiator cap increases, the cooling in the cooling water circulation circuit between the radiator and the water jacket Since the amount of water is reduced, it is difficult to accurately detect the reduction of the cooling water simply by controlling the rotation of the electric fan in accordance with the cooling water temperature in the radiator as in the conventional case.
[0004]
The present invention has been made in view of such circumstances, and is a vehicle water-cooled engine that stabilizes the temperature of the cooling water by preventing a decrease in the amount of cooling water in the cooling water circulation circuit between the radiator and the water jacket. An object of the present invention is to provide a temperature stabilization device for cooling water.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is a water-cooled engine for a vehicle in which a crankshaft is connected to a drive wheel via a centrifugal clutch that transmits power as the engine speed increases. a temperature detector water jacket for circulating cooling water is detected in that provided in the engine body, and an engine control unit capable of changing the output of the engine, the temperature representing the temperature of the water in the water jacket between, A control unit for controlling the engine control means so as to reduce the output of the engine in response to the detected temperature of the temperature detector reaching a set temperature, and the set temperature is cooled in the water jacket. It is set to a value corresponding to the boiling temperature of water, said engine control means, so as to reduce the output of the engine Wherein said reducing the engine speed to a set rotational speed is a centrifugal clutch of the connection rotation speed than when it is controlled by the control unit.
[0006]
According to such a configuration, when the detection value of the temperature detector that detects the temperature representative of the water temperature in the water jacket reaches the temperature corresponding to the boiling temperature of the cooling water in the water jacket, the control unit Controls the engine control means to reduce the engine output, so that the boiling of the cooling water in the water jacket is prevented from continuing and the evaporation of the cooling water from the radiator is suppressed, and between the radiator and the water jacket The amount of cooling water in the cooling water circulation circuit can be prevented and the temperature of the engine cooling water can be stabilized. Further, the engine control means reduces the engine speed to a set speed that is equal to or higher than the connection speed of the centrifugal clutch when controlled by the control unit so as to reduce the engine output. The driver can accurately detect the control state while relaxing.
[0007]
According to a second aspect of the invention, in addition to the configuration of the first aspect of the invention , a timing chain is provided on one side of the engine body, and the temperature detector directly detects the water temperature in the water jacket. Te characterized in that attached to the other side of the engine body, according to this structure, boiling of the cooling water in the cooling water circulation circuit between the radiator and water jacket can be detected promptly.
[0008]
According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the temperature detector is attached to a side portion of the engine body on the side where the spark plug is provided .
[0009]
The invention of claim 4 is characterized in that, in addition to the configuration of the invention of claim 2, the temperature detector is attached to the engine body so as to directly detect the water temperature at the bottom in the water jacket, According to such a configuration, it is possible to reliably detect boiling of the cooling water even if the cooling water is reduced.
[0010]
Further, the invention of claim 5 is in addition to the structure of the invention of claim 1, wherein the radiator is interlocked with and connected to the crankshaft so that the heat dissipation capacity of the radiator is always larger than the heat generation amount of the engine. According to such a configuration, the boiling of the cooling water does not occur in a normal state, so that the boiling caused by the reduction of the cooling water in the cooling water circulation circuit can be accurately performed. Therefore, the boiling of the cooling water in the water jacket can be prevented from continuing, the amount of cooling water in the cooling water circulation circuit can be prevented from decreasing, and the temperature of the engine cooling water can be stabilized.
[0012]
Further, in the invention of claim 6 , in addition to the structure of any one of claims 1 to 5 , the engine body has a cylinder disposed toward the front of the vehicle body, and the upper part of the cylinder head of the engine body has the water A cooling water pipe that returns from the jacket to the filler neck of the radiator is connected.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.
[0014]
1 to 7 show an embodiment of the present invention, FIG. 1 is an overall side view of a scooter type motorcycle, FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1, and FIG. FIG. 4 is a view taken along the line 4-4 in FIG. 2, FIG. 5 is a view of the power unit seen from the direction of the arrow 5-5 in FIG. 1, FIG. 6 is a control system diagram of the engine, FIG. These are figures which show the control period according to detection temperature and ON / OFF of a main switch.
[0015]
First, in FIG. 1, a vehicle body frame F of a scooter type motorcycle V having a front wheel Wf steered by a steering handle 11 and a rear wheel Wr driven by a swing type power unit P includes a front frame 12, a center The frame 13 and the rear frame 14 are divided into three. The front frame 12 is composed of an aluminum alloy casting that integrally includes a head pipe 12a, a down tube 12b, and a step floor support portion 12c. The center frame 13 on which the power unit P is supported so as to be swingable up and down via the pivot 15 is made of an aluminum alloy casting and is coupled to the rear end of the front frame 12. The rear frame 14 extending rearward and upward of the power unit P is composed of an annular pipe material, and a fuel tank 16 is supported on the upper surface thereof. A helmet case 17 is supported on the upper surface of the center frame 13, and the helmet case 17 and the fuel tank 16 are covered with a cover 19 having a seat 18 integrally.
[0016]
The power unit P is formed by integrally connecting a water-cooled single-cylinder four-cycle engine E with a cylinder disposed toward the front of the vehicle body and a belt-type continuously variable transmission T extending from the left side surface of the engine E to the rear of the vehicle body. The rear upper surface of the belt type continuously variable transmission T is coupled to the rear end of the center frame 13 via the rear cushion 20. An air cleaner 21 is supported on the upper surface of the belt-type continuously variable transmission T, a muffler 22 is supported on the right side surface of the belt-type continuously variable transmission T, and a main stand 23 that can stand and fall on the lower surface of the engine E. Supported.
[0017]
2 to 4, the engine body 24 of the engine E includes first and second engine blocks 27 and 28 that are divided by a split surface 26 that extends in the vertical direction along the crankshaft 25. The block 27 constitutes a cylinder block 27a and a crankcase half 27b, and the second engine block 28 constitutes the other half of the crankcase. A cylinder head 29 constituting the engine body 24 together with the first and second engine blocks 27 and 28 is coupled to the front end of the first engine block 27, and a head cover 30 is coupled to the front end of the cylinder head 29. A generator cover 31 is coupled to the right side surfaces of the first and second engine blocks 27 and 28.
[0018]
The belt type continuously variable transmission T includes a right casing 32 and a left casing 33 coupled to each other, and the front right side surface of the right casing 32 is located on the left side surfaces of the first and second engine blocks 27, 28. Combined. A reduction gear casing 34 is coupled to the rear right side surface of the right casing 33.
[0019]
A piston 36 slidably fitted inside a cylinder 35 provided in the first engine block 27 is connected to the crankshaft 25 via a connecting rod 37. A camshaft 38 is rotatably supported on the cylinder head 29, and an intake valve and an exhaust valve (not shown) provided on the cylinder head 29 are driven to open and close by the camshaft 38. A timing chain 40 is housed in a chain passage 39 provided in the first engine block 27, and the timing chain 40 includes a drive sprocket 41 provided on the crankshaft 25 and a driven sprocket 42 provided on the camshaft 38. Wrapped around. As a result, the camshaft 38 rotates once for every two rotations of the crankshaft 25.
[0020]
A drive pulley 43 is provided at the left end of the crankshaft 25 protruding into the right casing 32 and the left casing 33. The drive pulley 43 includes a fixed pulley half 44 fixed to the crankshaft 25 and a movable pulley half 45 that can approach and separate from the fixed pulley half 44. The half body 45 is urged in a direction approaching the stationary pulley half 44 by a centrifugal weight 46 that moves radially outward in accordance with an increase in the rotational speed of the crankshaft 25.
[0021]
A driven pulley 48 provided on an output shaft 47 supported between the rear portion of the right casing 32 and the speed reducer casing 34 includes a fixed pulley half 49 supported on the output shaft 47 so as to be relatively rotatable, and a fixed pulley half. A movable pulley half 50 that can approach and separate from the body 49 is provided, and the movable pulley half 50 is biased toward the fixed pulley half 49 by a spring 51. Further, a centrifugal clutch 52 is provided between the stationary pulley half 49 and the output shaft 47. The centrifugal clutch 52 enters a power transmission state as the engine speed exceeds the set speed. An endless V-belt 53 is wound around the drive pulley 43 and the driven pulley 48.
[0022]
An intermediate shaft 54 and an axle 55 that are parallel to the output shaft 47 are supported between the right casing 32 and the speed reducer casing 34, and a reduction gear train 56 is provided between the output shaft 47, the intermediate shaft 54, and the axle 55. A rear wheel Wr, which is a drive wheel, is provided at the right end of the axle 55 that passes through the reduction gear casing 34 and protrudes to the right.
[0023]
Thus, the rotational power of the crankshaft 25 is transmitted to the drive pulley 43, and is transmitted from the drive pulley 43 to the rear wheel Wr via the V belt 53, the driven pulley 48, the centrifugal clutch 52, and the reduction gear train 56.
[0024]
The AC generator 57 provided on the right side of the crankshaft 25 is covered with the generator cover 31, and a radiator 58 is provided on the right side of the generator cover 31. In order to supply cooling air to the radiator 58, a cooling fan 59 fixed to the right end of the crankshaft 25 is disposed between the AC generator 57 and the radiator 58. Thus, the heat dissipation capacity of the radiator 58 is always larger than the heat generation amount of the engine E.
[0025]
The cooling fan 59 and the radiator 58 are covered with a synthetic resin cover 60 fastened to the generator cover 31, and a louver 61 for introducing air from the outside is provided on the outer surface of the cover 60.
[0026]
The cylinder block 27 a of the first engine block 27 and the cylinder head 34 are provided with a water jacket 62, and a cooling water pump 63 that sucks the cooling water in the water jacket 62 is connected to the right end of the camshaft 38. The A thermostat case 65 that houses a thermostat 64 that switches whether the coolant discharged from the coolant pump 63 is guided to the radiator 58 according to the temperature of the coolant is coupled to the right side surface of the cylinder head 34. The cooling water pump 63 is housed in a space surrounded by the cylinder head 34 and the thermostat case 65.
[0027]
Referring also to FIG. 5, the front lower portion of the radiator 58 and the thermostat case 65 are connected by a cooling water pipe 66, and the thermostat case 65 and the water jacket 62 in the first engine block 27 are connected by a cooling water pipe 67. Is done.
[0028]
A rear fender 68 that covers the rear wheel Wr from above is attached to the power unit P so as to swing together with the radiator 58, and a flexible water supply such as a rubber hose is provided in a water supply port 58a provided at the rear upper part of the radiator 58. A filler neck 70 connected via a pipe 69 is detachably fastened to the rear fender 68. The upper end opening of the filler neck 70 is closed with a cap 71 so as to be opened and closed.
[0029]
The filler neck 70 is provided with an overflow pipe 70a for overflowing cooling water, and the overflow pipe 70a is connected to a reservoir tank (not shown). The filler neck 70 and the water jacket 62 in the cylinder head 29 are connected by a flexible cooling water pipe 72 such as a rubber hose.
[0030]
In a state where the warm-up operation of the engine E is completed, the cooling water discharged from the cooling water pump 63 driven by the camshaft 38 passes through the thermostat case 65 and the cooling water pipe 67, and the first engine block 27 and the cylinder head 29. It is supplied to the inner water jacket 61, and after passing through it, the engine E is cooled and then supplied to the radiator 58 via the cooling water pipe 71, the filler neck 70 and the water supply pipe 69. Then, the cooling water whose temperature has decreased while passing through the radiator 58 is returned to the cooling water pump 63 through the cooling water pipe 66 and the thermostat 64. On the other hand, when the engine E is warming up and the cooling water temperature is low, the thermostat 64 is operated, and the cooling water circulates inside the engine E without passing through the radiator 58 and quickly rises in temperature.
[0031]
In FIG. 6, the operation of the engine E is controlled by the control unit 75, and electric power from the battery 77 is supplied to the control unit 75 according to the conduction of the main switch 78. It is also possible to charge the battery 77 with DC power obtained by rectifying AC power generated by the AC generator 57 with the regulator 79.
[0032]
The main switch 78 is connected to a parallel circuit including a stop switch 80 that is turned on in response to a front-wheel brake operation and a stop switch 81 that is turned on in response to a rear-wheel brake operation. When at least one of the stop switches 80 and 81 is turned on in the conductive state, the stop lamp 82 is turned on.
[0033]
The parallel circuit composed of the both stop switches 80 and 81 is connected to the control unit 75 via the starter switch 83, and at least one of the both stop switches 80 and 81 is conductive, that is, the front wheel side and the rear wheel side. When the starter switch 83 is turned on while at least one of the brakes is being operated, a signal instructing the start of the engine E is input to the control unit 75. The control unit 75 controls the relays 84, 85, and 86 in response to the signal input to start the starter motor 87, whereby the engine E is started.
[0034]
Further, the control unit 75 responds to a signal from the pulse generator 88 for detecting the rotational speed of the engine E, a detection signal from the fuel detector 89 for detecting the remaining amount of fuel in the fuel tank 16, and a throttle closing operation. A detection signal of a throttle sensor 90 that detects a throttle opening for temporarily stopping the engine E is input to the control unit 75.
[0035]
A carburetor (not shown) provided in the intake system of the engine E is provided with a bypass starter 91 that controls the fuel supply amount at the start in accordance with the expansion and contraction of the wax heated by the PTC heater. The PTC heater of the bypass starter 91 is also controlled by the control unit 75.
[0036]
Further, a detection value of a temperature detector 74 that detects a temperature representative of the water temperature in the water jacket 62 is input to the control unit 75, and the control unit 75 responds to the detection value of the temperature detector 74 with the engine E. The ignition device 76 is controlled as an engine control means capable of changing the output of.
[0037]
That is, as shown in FIG. 7, the control unit 75 sets the detected temperature of the temperature detector 74 to a set temperature TS (for example, 130 ° C.) set as a value corresponding to the boiling temperature of the cooling water in the water jacket 62. In response, the ignition device 76 is controlled to reduce the output of the engine E by thinning the ignition timing to such an extent that the traveling speed of the motorcycle is set to 30 km / h, for example. It stops in response to the ignition off due to the shutoff of the switch 78.
[0038]
Further, the control unit 75 performs control so that the display lamp 92 shown in FIG. 6 blinks in a control state in which the ignition timing is thinned out, and the blinking of the display lamp 92 causes an abnormality in the cooling water circulation circuit. To be notified.
[0039]
As shown in FIG. 3, the temperature detector 74 is attached to the cylinder block 27a in the engine body 24 so as to directly detect the water temperature in the water jacket 62. Further, the temperature detector 74 is a water detector. It is attached to the cylinder block 27a so as to directly detect the water temperature at the bottom in the jacket 62.
[0040]
Next, the operation of this embodiment will be described. The detection value of the temperature detector 74 that detects the temperature representative of the water temperature in the water jacket 62 to the set temperature TS corresponding to the boiling temperature of the cooling water in the water jacket 62. Is reached, the control unit 75 controls the ignition device 76 so as to reduce the output of the engine E, and the ignition is thinned out, so that the boiling of the cooling water in the water jacket 62 is prevented from continuing. Thus, the evaporation of the cooling water from the radiator 58 can be suppressed, and the cooling water amount in the cooling water circulation circuit between the radiator 58 and the water jacket 62 can be prevented from decreasing to stabilize the cooling water temperature of the engine E.
[0041]
Further, since the temperature detector 74 is attached to the cylinder block 27a of the engine body 24 so as to directly detect the water temperature in the water jacket 62, the boiling of the cooling water in the cooling water circulation circuit between the radiator 58 and the water jacket 62 is quickly caused. Since the temperature detector 74 directly detects the water temperature at the bottom of the water jacket 62, it is possible to reliably detect the boiling of the cooling water even if the cooling water is reduced. can do.
[0042]
Further, the radiator 58 is provided with a cooling fan 59 linked to and coupled to the crankshaft 25, and the heat dissipation capacity of the radiator 58 is always larger than the heat generation amount of the engine E. For this reason, the boiling of the cooling water does not occur in a normal state, the boiling accompanying the decrease of the cooling water in the cooling water circulation circuit can be accurately detected, and the cooling water in the water jacket 62 is detected. It is possible to prevent the boiling from continuing, prevent the cooling water amount from decreasing in the cooling water circulation circuit, and stabilize the cooling water temperature of the engine E.
[0043]
As another embodiment of the present invention, instead of controlling to reduce the output of the engine E by thinning out the ignition timing, the engine speed is reduced to a set speed that is equal to or higher than the connection speed of the centrifugal clutch 52. As described above, the ignition device 76 may be controlled so as to completely misfire in a stepwise manner, so that the driver can accurately detect the control state while slowing down the engine output. it can.
[0044]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.
[0045]
【The invention's effect】
As described above, according to the invention of claim 1 , the detection value of the temperature detector that detects the temperature representative of the water temperature in the water jacket reaches the temperature corresponding to the boiling temperature of the cooling water in the water jacket. Sometimes, the control unit controls the engine control means so as to reduce the engine output, so that the boiling of the cooling water in the water jacket is prevented from continuing and the evaporation of the cooling water from the radiator is suppressed, The cooling water amount can be prevented from decreasing in the cooling water circulation circuit between the radiator and the water jacket, and the engine cooling water temperature can be stabilized. Further, when the engine control means is controlled by the control unit so as to reduce the output of the engine, the engine control means reduces the engine speed to a set speed that is equal to or higher than the connection speed of the centrifugal clutch between the engine and the driving force. Thus, it is possible to cause the driver to accurately detect the control state while moderately decreasing the engine output.
[0046]
According to the invention of claim 2, it is possible to quickly detect boiling of the cooling water in the cooling water circulation circuit between the radiator and the water jacket .
[0047]
According to the invention of claim 4, it is possible to reliably detect the boiling of the cooling water even if the cooling water is reduced.
[0048]
Furthermore, according to the invention of claim 5, it is possible to accurately detect the boiling accompanying the decrease of the cooling water in the cooling water circulation circuit, and to prevent the cooling water from boiling in the water jacket. It is possible to prevent the cooling water amount from decreasing in the cooling water circulation circuit and to stabilize the temperature of the engine cooling water.
[Brief description of the drawings]
FIG. 1 is an overall side view of a scooter type motorcycle.
FIG. 2 is an enlarged cross-sectional view taken along line 2-2 of FIG.
FIG. 3 is an enlarged view of a main part of FIG.
4 is a view taken along line 4-4 in FIG.
5 is a view of the power unit as seen from the direction of arrows 5-5 in FIG.
FIG. 6 is a control system diagram of the engine.
FIG. 7 is a diagram illustrating a control period according to a detected temperature and on / off of a main switch.
[Explanation of symbols]
24 ... Engine body 25 ... Crankshaft 52 ... Centrifugal clutch 58 ... Radiator 59 ... Cooling fan 62 ... Water jacket 74 ... Temperature detector 75 ... Control unit 76 ..Ignition device E as engine control means Engine

Claims (6)

A vehicle water-cooled engine (E) in which a crankshaft (25) is connected to drive wheels (Wr) via a centrifugal clutch (52) that transmits power as the engine speed increases.
In the engine body (24) provided with a water jacket (62) for circulating cooling water between the radiator (58) and
Engine control means (76) capable of changing the output of the engine (E), a temperature detector (74) for detecting a temperature representative of the water temperature in the water jacket (62), and a temperature detector (74) A control unit (75) for controlling the engine control means (76) to reduce the output of the engine (E) in response to the detected temperature reaching a set temperature;
The set temperature is set to a value corresponding to the boiling temperature of the cooling water in the water jacket (62);
When the engine control means (76) is controlled by the control unit (75) so as to reduce the output of the engine (E), the engine control means (76) is set to a set rotational speed that is equal to or higher than the connected rotational speed of the centrifugal clutch (52). An apparatus for stabilizing the temperature of cooling water in a water-cooled engine for vehicles, wherein the engine speed is reduced.   A timing chain (40) is provided on one side of the engine body (24), and the temperature detector (74) detects the water temperature in the water jacket (62) directly so that the other of the engine body (24). The temperature stabilization device for cooling water in a water-cooled engine for a vehicle according to claim 1, wherein the temperature stabilization device is mounted on a side.   The said temperature detector (74) is attached to the side part by which the spark plug is provided of the engine main body (24), The cooling water in the water-cooled engine for vehicles of Claim 1 or 2 characterized by the above-mentioned. Temperature stabilization device.   The vehicle water-cooled type according to claim 2, wherein the temperature detector (74) is attached to the engine body (24) so as to directly detect the water temperature at the bottom of the water jacket (62). Cooling water temperature stabilizer in the engine.   The radiator (58) has a cooling fan (59) linked to and connected to the crankshaft (25) so that the heat dissipation capacity of the radiator (58) is always larger than the heat generation amount of the engine (E). The temperature stabilization device for cooling water in a water-cooled engine for a vehicle according to claim 1, wherein the temperature stabilization device is attached. Engine body (24) is arranged the cylinder towards the front of the vehicle body, the upper portion of the cylinder head (29) of the engine body (24), the filler neck of the radiator (58) from the water jacket (62) ( 70. The cooling water temperature stabilization device for a water-cooled engine for a vehicle according to any one of claims 1 to 5, wherein a cooling water pipe (72) returning to 70) is connected.

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