Patent ID: 8186604

Claim:
A thermostat apparatus in a coolant circuit of an engine, said apparatus comprising: a temperature sensitive movable part including a thermal extension body configured to thermally expand to contract in response to a change in temperature of a coolant, and a piston shaft having one end retained in the temperature sensitive movable part and being configured to slide in response to the thermal expansion or contraction of the thermal extension body, a main valve of the thermostat apparatus being opened or closed when the piston shaft is driven; and a conduit configured so as to bypass a high-temperature coolant heated by the engine to the thermostat apparatus, the conduit being configured so as to extend until the conduit covers all of or a part of the temperature sensitive movable part and form a high-temperature coolant conduit having an inside diameter commensurate with an outside diameter of the temperature sensitive movable part so as to cause the high-temperature coolant flowing through the conduit to directly contact a periphery of the temperature sensitive movable part without impairing a temperature and a flow rate of the high-temperature coolant, and let the high-temperature coolant flow out of an ejection opening.