PURPOSE: To improve the responsiveness of control, by setting an upper limit of revolving speed of a stepping motor in response to throttle opening, in case of a device which drives and controls a throttle valve by means of the stepping motor.
CONSTITUTION: A throttle valve to be opened or closed by a stepping motor MA is installed in a suction pipe, and this stepping motor MA is controlled by a driving control means MB according to a driving state. And, the throttle valve is energized in the closing direction by an energizing means MC with energizing force corresponding to the opening. In this case, also there is provided with at throttle opening detecting means MD which detects the extent of throttle opening, while the driving control device MB is constituted of installing an engine speed limiting means ME which sets an upper limit of revolving speed of the stepping motor MA according to the detected throttle opening. With this constitution, such control that is good in responsiveness is made performable irrespective of energizing force of the energizing means MC being increased with the throttle opening.
TAKEUCHI KANJI
ABE TOMOAKI
TAKAO MITSUNORI
