Internal combustion engine control with fast exhaust catalyst warm-up
AssigneeNippondenso Co., Ltd.
InventorsDaiji Isobe, Kenichi Sago, Shigenori Isomura
Life of this patent
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Abstract
In an engine exhaust catalyst warm-up control, ignition timing is delayed from normal first to raise the catalyst temperature, and then a fuel injection amount is dithered to increase and decrease alternately from a normal amount until the catalyst temperature reaches the catalyst activation completion temperature. In place of the ignition delay control, afterburning control may be employed in which fuel cut for a cylinder and fuel increase for the other cylinders are executed. Further, the catalyst warm-up control may be performed by controlling a supercharging operation and an exhaust gas recirculation operation cooperatively.
Claims10
A catalyst warm-up system for an internal combustion engine, comprising:
- an exhaust gas purifying catalyst arranged in an exhaust system of said internal combustion engine;
- ignition timing calculation means for calculating an ignition timing on the basis of a running state of said internal combustion engine;
- fuel injection amount calculation means for calculating a fuel injection amount on the basis of the running state of said internal combustion engine;
- and
- fast warm-up means for warming up said catalyst fast until a warm-up of said catalyst is completed after a start of said internal combustion engine, said fast warm-up means including first fast warm-up means for correcting said ignition timing to a delay side and second fast warm-up means for executing an injection dither control to correct an increase/decrease in said fuel injection amount, the catalyst warm-up by said second fast warm-up means being executed after the catalyst warm-up by said first fast warm-up means.
A catalyst warm-up system for an internal combustion engine, comprising:
- an exhaust gas purifying catalyst arranged in an exhaust path of the internal combustion engine;
- fuel injection amount calculation means for calculating a fuel injection amount on the basis of a running state of said internal combustion engine;
- and
- injection dither control means for executing an injection dither control to correct an increase/decrease in said fuel injection amount until a warm-up completion of said catalyst is detected after the start of said internal combustion engine thereby to warm-up said catalyst fast,
- said injection dither control means switching a ratio of rich mixture cylinders to be corrected to increase the fuel injection amount and lean mixture cylinders to be corrected to decrease the fuel injection amount, in accordance with a total of injection dither amount.
Dependencies are inferred from the claim text.