| 摘要 |
<p>PURPOSE:To reduce NOx emission effectively by retarding the ignition timing when the sensed temp. of the exhaust gas upstream of catalyst is lower than the target temp., and shifting the fuel injection timing when the sensed temp. is higher in the direction in which the temp. of the exhaust gas sinks. CONSTITUTION:An engine 1 is provided with a catalyst 19 in an exhaust passage 12 for purifying the exhaust gas. An oxygen sensor 20 and a temp. sensor 21 for sensing the temp. of exhaust gas at the inlet to the catalyst are installed upstream of the catalyst 19. On the basis of sensing signals from the temp. sensor 21, etc., a control unit 31 controls an injector 18, spark lug 27, ignitor 26, and distributor 28. That is, when the sensed temp. of the exhaust gas is lower than the target temp. value, the ignition timing is delayed. When higher, the fuel injection timing is shifted in the direction in which the temp. of the exhaust gas sinks.</p> |
