HEAT SENSING VALVE

PURPOSE:To prevent a cylinder valve rod or the like from breakage by pressing connectively the valve rod against a valve body through a connecting spring and providing an escape space in the valve body not to transmit the drive force of an output rod to the valve body when the valve is fully closed. CONSTITUTION:Since a valve hole 10 is largely opened in the start of an engine, a lot of bypassed auxiliary air is supplied from auxiliary paths 4a, 4b to the engine 1 even when a throttle valve 3 is fully closed to improve the starting property. Also, warming-up running proceeds, and cooling water temperature is raised so that a heat sensing section 13 detects the rise of water temperature to extend an output rod 14a. The extension of the rod 14a slides a valve rod 20 rightward. Thus, a valve body 22 approaches the valve hole 10 through a connecting spring 25 against a return spring 26. Hence, since the opening of the valve hole is reduced the auxiliary air amount is reduced. And when the warming-up running is completed and the water temperature reaches a set temperature, the valve body 22 closes completely the valve hole 10 to shut off the supply of the auxiliary air so that the normal idling condition is provided. When the water temperature is further raised, an end of the valve rod 20 escapes in an escapement portion 20b to prevent the valve rod and others from breakage.