Patent ID: 8042745

Claim:
A thermally responsive valve for regulating engine coolant flow comprising: a thermal expansion element which thermally expands and contracts according to a thermal change of coolant flowing in a coolant circuit of an engine; an operating member which contains the thermal expansion element, a longitudinal length of the operating member being changed due to a thermal expansion and a thermal contraction of the thermal expansion element; and a valve element for opening and closing the coolant circuit, which connects the engine and a heat exchanger with each other, according to a change of the longitudinal length of the operating member due to a volume change of the thermal expansion element, wherein the thermal expansion element includes at least two kinds of thermal expansion elements including a first thermal expansion element and a second thermal expansion element, wherein a thermal expansion start temperature of the first thermal expansion element is lower than a thermal expansion start temperature of the second thermal expansion element, wherein a thermal expansion response speed of the first thermal expansion element is lower than a thermal expansion response speed of the second thermal expansion element, wherein the valve element is opened by the first thermal expansion element at a response speed rate, and wherein an opening degree of the valve element becomes from 0% to 10% for approximately 30 seconds after the first thermal expansion element starts to expand at approximately 80 ° C.