PURPOSE: To provide a throttle valve on-off control unit that is inexpensive and excellent in controllability and reliability by taking such a proper step as installing a double diaphragm as a mechanical connecting means and a valve opening mechanism in space between an accelerator pedal and a throttle shaft.
CONSTITUTION: At the usual, a throttle shaft 27 and an actuator 22 are connected to each other through a magnetic clutch 29, while an airtight chamber 33 of a double diaphragm unit 30 is opened to the atmosphere by a selector valve 8. With the operation of an accelerator pedal, the actuator 22 is driven by a control circuit 21, thereby opening or closing a throttle valve 28 in an intake passage 20. In addition, with operating force of the accelerator pedal 2, a first diaphragm 3 is pulled up via an accelerator wire 6 or the like. Since the airtight chamber 33 is opened to the atmosphere, however, a second diaphragm 4 is held downward. Therefore the first diaphragm 3 is idling and the operating force will in no case be transmitted to a valve opening mechanism 40 via a connecting link 5.
KITAMURA SUNAO
TAKEUCHI HITOSHI
TANAKA SHINICHIRO
TOYOTA MOTOR CORP