| 摘要 |
<p>A control unit 90 executes control operation, by which the secondary air control unit 83 is closed and the closing state is kept for the specified duration T1 or the specified duration T2, when receives speed/opening angle reduction information informing about transition from the state, in which the engine speed Ne exceeds the set engine speed E or the throttle openings &thetas; th exceeds the set throttle opening F to the full-open side, to the region, in which, the engine speed Ne is the set engine speed E or lower and the throttle openings &thetas; th is the set throttle opening F or less, namely, the zone A. The control of opening and closing of the air regulating valve by the engine speed and the throttle opening allows accurate exhaust purification in comparison with the conventional method. In addition, keeping the closed state of the air regulating valve for the specified duration allows exhausting the unburned component contained in the exhaust gas in the exhaust path in the specified duration to realize reliable prevention of afterburning. <IMAGE></p> |
