Internal-combustion engines – Cooling – Automatic coolant flow control
Reexamination Certificate
1998-09-01
2001-12-04
Wolfe, Willis R. (Department: 3747)
Internal-combustion engines
Cooling
Automatic coolant flow control
C123S14250R
Reexamination Certificate
active
06325026
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a cooling water recirculation apparatus for an internal combustion engine.
2. Description of the Related Art
In a cooling water recirculation apparatus for an internal combustion engine, heat irradiated from an internal combustion engine body is absorbed by cooling water, and a part of the absorbed heat is utilized as a heat source for a passenger room heater.
For this reason, the cooling water that has flowed through an engine interior cooling water communication passage provided in the internal combustion engine body, i.e., a so-called water jacket and that has been warmed by absorbing the heat from the internal combustion engine body during the passage is fed out from the internal combustion engine body to the passenger room heater through a heater side cooling water recirculation circuit for connecting the internal combustion engine body and the passenger room heater to each other for recirculation.
However, immediately after the starting operation of the internal combustion engine, since the cooling water is less warmed up, the passenger room heater less works.
Accordingly, for instance, Japanese Utility Model Publication Laid-Open No. Sho 59-14706 discloses a technique for providing, in a midway of the heater side cooling water recirculation circuit, a heating device for heating the cooling water by using the exhaust gas of the internal combustion engine as a heat medium, and operating the heating device upon the warming-up operation of the internal combustion engine to heat the cooling water for the passenger room heater. According to this technique, the effect of the passenger room heater upon the starting operation of the internal combustion engine is more enhanced than that of the conventional one.
However, even according to the technique disclosed in the above-described publication, since the cooling water is caused to always flow to the passenger room heater upon the warming operation, an amount of the recirculation of the cooling water is increased. Also, since the heat is radiated in the passenger room heater even if the cooling water is heated by the heating device, the heating efficiency of the overall recirculated cooling water is degraded. As a result, the enhancement of the effect of the heater is not satisfactory.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above-noted defects, and therefore an object of the present invention is to accelerate a starting operation of a heater upon starting an internal combustion engine and to sufficiently accelerate the warming-up operation.
In order to attain this and other objects, according to the present invention, there is provided a cooling water recirculation apparatus for an internal combustion engine, comprising: an internal combustion engine body having a cooling water internal passage for cooling a portion around a cylinder; a radiator for irradiating heat of the internal combustion engine body, absorbed by the cooling water to atmosphere; a passenger room heater using a part of the cooling water as a heat medium; a radiator side cooling water recirculation circuit for recirculating the cooling water between the cooling water internal passage of the internal combustion engine body and the radiator; a heater side cooling water recirculation circuit for recirculating the cooling water between the cooling water internal passage of the internal combustion engine body and the heater; a radiator bypass circuit for returning the cooling water, that has been discharged from the cooling water internal passage of the internal combustion engine body, back to the cooling water internal passage, bypassing the radiator; a cooling water passage switching means for closing the radiator bypass circuit when a temperature of the cooling water exceeds a radiator water passage allowance temperature, thereby allowing the cooling water to flow through the radiator side cooling water recirculation circuit, and for closing the radiator side cooling water recirculation circuit when the temperature of the cooling water is not higher than the radiator water passage allowance temperature, thereby allowing the cooling water to flow through the radiator bypass circuit; and an auxiliary heating means for heating the cooling water, provided separately from the internal combustion engine body.
Namely, it is characterized in that: there is further provided a flow rate control valve provided downstream of the cooling water internal passage of the internal combustion engine body and upstream of the passenger room heater in the heater side cooling water recirculation circuit, for reducing an amount of the cooling water flowing through the heater side cooling water recirculation circuit when the temperature of the cooling water is not higher than a heater water passage limit temperature that is set to be not higher than the radiator water passage allowance temperature; and the auxiliary heating means is provided in a portion where the cooling water is recirculated when the temperature of the cooling water is not higher than the heater water passage limit temperature.
In this case, it is possible to employ an electric heater or a burning type heater for the auxiliary heating means.
The cooling water flow passage switching means may be a thermostat or a thermostat type flow passage switching valve for switching the flow passage by using the radiator water passage allowance temperature as a threshold value.
Also, the flow rate control valve may be a thermostat or a thermostat type flow rate control valve for opening and closing by using the heater water passage limit temperature as a threshold value. When the cooling water is warmed up so that the flow rate control valve is opened, the cooling water is recirculated through the heater side cooling water recirculation circuit, and when the cooling water is cooled so that the flow rate control valve is closed, the cooling water is not recirculated through the heater side cooling water recirculation circuit. However, the flow rate control valve does not take a structure such that no cooling water flows in the closed condition. It is preferable to allow a small amount of the cooling water to flow for detecting the temperature of the cooling water to a degree that the temperature thereof can be detected.
The heater water passage limit temperature for controlling the opening/closing of the flow rate control valve is set to be equal to or lower than the radiator water passage allowance temperature for controlling the flow passage switching of the cooling water passage switching means. Accordingly, when the flow rate control valve is closed and the cooling water is not recirculated through the heater side cooling water recirculation circuit, the radiator side cooling water recirculation circuit is always closed and the cooling water is not recirculated through this circuit but recirculated only through the radiator bypass circuit.
Accordingly, when the temperature of the cooling water is so low that the temperature of the cooling water closes the flow rate control valve as in the starting operation, the cooling water is recirculated only through the radiator bypass circuit. At this time, the cooling water flowing through the cooling water internal passage of the internal combustion engine body absorbs the heat from the internal combustion engine body and at the same time absorbs the heat from the auxiliary heating means. On the other hand, at this time, the cooling water does not flow through the heater side cooling water recirculation circuit at all and even though the water flows, the amount of the water is very small. Therefore, an amount of radiated heat from the heater is very small. Namely, since the heat which is received by the cooling water is very large and the irradiated heat from the cooling water is very small, it is possible to quickly elevate the temperature of the cooling water. As a result, it is possible to quickly elevate the temperature of the internal combustion engine body,
Benton J A
Kenyon & Kenyon
Toyota Jidosha & Kabushiki Kaisha
Wolfe Willis R.
LandOfFree
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