CATALYST PROTECTION DEVICE AND CATALYST PROTECTION METHOD FOR INTERNAL COMBUSTION ENGINE

摘要

A catalyst protection device includes: a catalyst provided in an exhaust system of an internal combustion engine and purifying exhaust gas; a bed temperature acquisition unit acquiring a current bed temperature of the catalyst; a base increase value calculation unit calculating a base increase value that is a base value of an increase value of a fuel injection amount injected by a fuel injection valve included in the internal combustion engine in order to cool the catalyst when the current bed temperature exceeds a predetermined determination value; a compensator acquiring a corrected increase value by correcting the base increase value using a reduction coefficient that is calculated by incorporating a value of a target bed temperature set to a value strictly lower than the determination value; and an injection amount increasing unit selecting any one of the base increase value and the corrected increase value. When catalyst protection is required, the fuel increase value is therefore optimized to reasonable values, while not being reduced too much.

主权项

1. A catalyst protection device for an internal combustion engine, comprising:
a catalyst that is provided in an exhaust system of the internal combustion engine and that purifies exhaust gas; a bed temperature acquisition unit configured to acquire a current bed temperature of the catalyst; and an injection amount increasing unit configured to increase an amount of fuel injected in the internal combustion engine when the current bed temperature exceeds a predetermined determination value, wherein the injection amount increasing unit is configured to increase the amount of injected fuel, by a first increase value that is obtained on the basis of (i) a first base increase value which is obtained on the basis of the operating state of the internal combustion engine, and (ii) a correction coefficient which is obtained on the basis of the current bed temperature and a target bed temperature lower than the predetermined determination value.