| 摘要 |
PURPOSE:To prevent runaway of an engine at the time of failure in an intake-air quantity sensor, etc. by making the upper and lower limits of a limiter which are applied to regulating output of an intake-air regulator for producing duty signals in relation to both actual intake-air quantity and desired intake-air quantity adjustable in response to an increase or decrease of the intake-air quantity. CONSTITUTION:In a case of controlling an intake-air control valve 8 installed between the passages 91 and 92 by-passing a throttle valve 3 by means of a drive unit 7, an error-amplifier 61 for calculating error in each output from a desired engine speed generator 5 and an engine speed sensor 42 is provided. Based on the error, an engine speed regulator 62 produces an engine speed regulating signal, and a desired intake-air quantity is set by means of a limiter 12. And then, the error between the desired intake-air quantity and the actual intake-air quantity sensored by an intake-air quantity sensor 10 is calculated by an error-amplifier 111. Further, based on the error, an intake- air regulator 112 produces an intake-air regulating signal and controls the drive unit 7 through a limiter 13. In this case, the limiter 13 is installed so that its upper and lower limits are set to be larger in the intake-air increasing side and smaller in the intake-air decreasing side.
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