JPS643237A - Drive by-wire type throttle valve control device with fail-safe mechanism - Google Patents

Abstract

PURPOSE:To accomplish fail-safe operation by switching a flapper to adjust the amount of intake air by a throttle valve of a normal actuator when one system of the first and second actuators fails. CONSTITUTION:During normal operation, a flapper 26 is held along a partition wall 25, so that the first and second throttle valves 3a, 3b are respectively controlled by the first and second actuators 6a, 6b according to a command from control means through the first and second intake passages, 1a, 1b. In this arrangement, when the first actuator 6a fails, the flapper 26 is pushed down to the first intake passage 1a side by angle switching means 27 to close the passage, so that air intake from the first intake passage 1a is conducted to the second intake passage 1b, and intake from both passages 1a, 1b is flow- adjusted through the second throttle valve 3b by the second actuator 6b to be sent to an internal combustion engine. Thus, fail-safe operation can be accomplished by a simple structure.