PURPOSE: To obtain proper control of a throttle valve even in case of a false contact of an idling switch when an actuator control of the throttle valve does not detect the failure by detecting a change of the driving condition of an auxiliary machinery with a load detecting means for driving the actuator.
CONSTITUTION: In case of a false contact (NG) of an idling switch ISW and the ISW is not put on, a motor 5 is controlled to rotate for pulling an actuator rod 7 backward with a pulse width of L1 till a motor position switch 10 is on after detecting that an air conditioner is switched from on to off. When the switch 10 is on, the rod 7 is pushed forward with a pulse width L2 by the rotational control of the motor 5 and stopped at the right standard opening PO when the switch 10 is off. Then, the rod 7 is projected up to the target opening degree PS, i.e. the water temperature opening degree PTW to keep an opening degree of a throttle valve 2 properly. This construction permits to eliminate a risk of speeding and improve the safety by controlling the throttle valve properly to maintain a high speed rotational state as it is.
HASHIMOTO TOORU
NAKAMURA SHIGEO
SUGIURA MAMORU
SAITOU YASUHIKO
YOSHIDA YOSHITAKA
