| 摘要 |
<p>The temperature of an engine exhaust gas treating device is maintained above a first predetermined value, above which the treating device can purify engine exhaust gases, by interrupting to control an air-fuel ratio of an air-fuel mixture burned in the engine to a desired value and having a mixture forming device form a rich air-fuel mixture, and further by providing a spark in the treating device, retarding the engine ignition timing and/or supplying secondary air into the engine exhaust gases when the treating device temperature is less than the predetermined value, and by resuming to control the air-fuel ratio to the desired value when the treating device temperature is higher than the predetermined value, and below a second predetermined value, below which the treating device is prevented from being damaged by heat, by stopping production of the spark and supply of the secondary air and restoring the engine ignition timing to a normal condition when the treating device temperature is higher than the second predetermined value.</p> |
