| 摘要 |
<p>PURPOSE:To prevent consumption of a useless power by a method wherein energizing heating of an energization heating type catalyst is stopped when oxidation reaction of an unburnt component in exhaust gas can not be made under a state of maintaining the air-fuel ratio in a lean state or a logic air-fuel ratio even through the feed of secondary air being made. CONSTITUTION:When a starter switch 42 is turned ON and an internal combustion engine 1 is started and the detecting value of a number of revolutions of engine sensor 39 exceeds a given, value, energization to a plurality of energization heating type catalysts 12 (a, b) from a battery 46 is started by means of an electronic control unit 30. When the temperature of the energization heating type catalyst 12 is increased to an activation temperature, an air pump 18 is driven to feed secondary air in an amount enough to bring the air-fuel ratio of exhaust gas into a lean state or a theoretical air-fuel ratio. The feed of secondary air causes oxidation reaction of an unburnt component in exhaust gas and the stop of energization to each energization heating type catalyst 12 occasioned by the generation of heat and the increase of temperature. In this case, when a trouble occurs to the air pump 18 and an air-fuel ratio is abnormal, energization to the energization heating type catalyst 12 is stopped.</p> |
