| 摘要 |
PURPOSE:To enhance responsive performance of an eigine by installing a time constant variable type negative pressure filter for eliminating ripple elements and a throttle alteration detector that temporarily reduces the time constant of the filter upon rapid changes of the throttle opening. CONSTITUTION:A differential circuit 42 issues differential output corresponding to the first transition of throttle opening signals while a differential circuit 44 issues differential output corresponding to last transition of the signals. The output becomes input to a buffer circuit 41 through a diode ore circuit 45. When input surpasses threshold value, in other words, the throttle opening changed rapidly, output reaches the H level, with an analog SW turning on. As a result, R1 and R2 are connected in parallel, resistance value declines, time constant diminishes and transitional responsive performance improves. When output rests with the L level, namely, changes of throttle opening are moderate, resistor R1 of a filter 1 is not used, the overall resistance value becomes big, time constant is also large and the ripple elimination rate proves high. Thus, responsive performance of the engine can be enhanced.
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