Reduction of light off time of three-way catalyst

摘要

The present invention relates to a three-way catalyst device provided in an exhaust device of a vehicle, and the three-way catalyst device provided in a conventional vehicle can perform the exhaust gas catalyst role only when heated to an efficient constant temperature of 250 ° C. or higher. It is economically burdened to have a separate catalyst device that is used only in low temperature conditions, especially in the catalyst device using spark timing retard, to start the vehicle to solve the problem of deterioration at low temperature. In this state, when the temperature of the coolant is 20 to 30 ° C., one cylinder of six cylinders is forcibly spark retarded in one cylinder during idling of the engine in the ECU 10. Burn the unburned gas, and burn the burnt unburned gas in the three-way catalyst device to reduce the temperature of the three-way catalyst device. By rapidly increasing the light off time leading to the efficient constant temperature of the three-way catalytic device (effect) it is effective to effectively reduce the emissions through the three-way catalyst device.