Internal-combustion engines – Cooling – Automatic coolant flow control
Reexamination Certificate
1999-10-05
2001-07-17
Wolfe, Willis R. (Department: 3747)
Internal-combustion engines
Cooling
Automatic coolant flow control
C123S041440, C123S041290, C123S041510
Reexamination Certificate
active
06260515
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an engine cooling system including a water pump for circulating cooling water in order to cool the engine. Furthermore, a thermostat is provided in the water pump in such a manner as to be openable/closable depending on the temperature of cooling water.
2. Description of Related Art
An engine cooling system of this type has been known, for example, from Japanese Patent No. 2560186.
In the above-described related art system, the casing of a water pump is composed of a pump body and a pump case fastened to the pump body. A thermostat having a portion protruding into the pump case is held between the pump cover and a thermostat cover fastened to the pump case in such a manner as to cover the thermostat. As a result, the prior art system requires the pump cover, the pump case, and the thermostat cover for providing the thermostat in the water pump. This causes a problem in that the number of parts is increased, thereby increasing the cost, weight and the number of assembling steps.
SUMMARY OF THE INVENTION
In view of the foregoing, the present invention has been made, and an object of the present invention is to provide an engine cooling system capable of providing a thermostat in a water pump with a reduced number of parts, thereby reducing the cost, weight and the number of assembling steps.
To achieve the above object, according to a first aspect of the present invention, there is provided an engine cooling system including a water pump for circulating cooling water in order to cool the engine. Furthermore, a thermostat is provided in the water pump in such a manner as to be openable/closable depending on the temperature of cooling water. A casing of the water pump is composed of a pump body for rotatably supporting a pump shaft, and a pump cover connected to the pump body in such a manner as to cover an impeller fixed to the pump shaft. The thermostat is contained in a containing portion formed in the pump cover in such a manner as to be held between the pump body and the pump cover. With this configuration, since the thermostat is provided in the water pump in such a manner as to be contained in the containing portion of the pump cover while being held between the pump body and the pump cover constituting the casing of the water pump, the number of parts decreases as compared with the related art system which requires the pump body, the pump case, and the thermostat cover. This makes it possible to reduce the cost, weight and the number of assembling steps.
According to a second aspect of the present invention, in addition to the configuration of the first aspect of the present invention, a first suction port opened to one end of the containing portion is provided in the pump body in such a manner as to be in communication with the radiators; a second suction port opened to the other end of the containing portion in such a manner as to introduce water which has been returned from the engine not by way of the radiators is provided in the pump cover; and the thermostat contained in the containing portion has a thermostat valve for opening/closing the first suction port and a bypass valve for opening/closing the second suction port. With this configuration, the bottom-bypass type cooling water circuit can be simplified by closing the thermostat valve and opening the bypass valve when the temperature of cooling water is low and opening the thermostat valve and closing the bypass valve as the temperature of cooling water is increased.
According to a third aspect of the present invention, in addition to the configuration of the first and second aspects of the present invention, a discharge port for discharging cooling water discharged depending on rotation of the impeller is provided in the pump cover. With this configuration, the circuit for introducing cooling water from the water pump can be simplified.
According to a fourth aspect of the present invention, in addition to the configuration of the first through third aspects of the present invention, the thermostat is disposed over the impeller. With this configuration, air in the water pump can be easily released through the thermostat.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 4828455 (1989-05-01), Kinbara et al.
patent: 4938185 (1990-07-01), Doke
patent: 5022354 (1991-06-01), Okita et al.
patent: 6112706 (2000-09-01), Heer
patent: 2-2560186 (1996-09-01), None
Harada Makoto
Inayama Tsuguto
Tosaka Tetsuya
Birch & Stewart Kolasch & Birch, LLP
Harris Katrina B.
Honda Giken Kogyo Kabushiki Kaisha
Wolfe Willis R.
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