Apparatus for controlling catalyst temperature and method for controlling catalyst temperature
AssigneeDenso Corporation
InventorYoshihiro Majima
Life of this patent
Estimating the term…
Abstract
A catalyst is warmed up by a rapid heating control that retards ignition timing and increases an intake air amount. Then the warm up is completed or a transmission is shifted to a drive range, the ignition timing is gradually advanced and the intake air amount is gradually decreased. Therefore, an engine speed is smoothly changed from the rapid heating control to the normal control without a torque shock. Additionally, a beginning of the advancing of the ignition timing is delayed by a predetermined delay time relative to a beginning of the decreasing of the intake air amount. The decreasing of the intake air amount prevents undesirable increase of the engine speed caused by the advancing of the ignition timing.
Claims24
An apparatus for controlling a catalyst temperature of an engine, comprising:
- rapid heating control means for retarding an ignition timing and increasing an intake air amount to accelerate a warming up of the catalyst;
- normal control means for controlling the ignition timing and the intake air amount after the rapid heating control means;
- and
- gradual control means for changing values provided by the rapid heating control means to values provided by the normal control means, wherein the gradual control means advances the ignition timing gradually and decreases the intake air amount simultaneously and gradually, and said gradual control means delays a beginning of the advancing for the ignition timing by a delay time of an intake air system relative to a beginning of the decreasing for the intake air amount.
A method for controlling a catalyst temperature of an engine, the method comprising:
- accelerating a warming up of the catalyst by retarding an ignition timing and increasing an intake air amount;
- controlling the ignition timing and the intake air amount subsequent to the accelerating step;
- and
- changing values gradually from values provided in the accelerating step to values provided in the controlling step by advancing the ignition timing gradually, and decreasing the intake air amount simultaneously and gradually, wherein a beginning of the advancing for the ignition timing is delayed by a delay time of an air intake system relative to a beginning of the decreasing for the air intake amount.
An apparatus for controlling a catalyst temperature of an engine, comprising:
- rapid heating control means for retarding an ignition timing and increasing an intake air amount to accelerate a warming up of the catalyst;
- normal control means for controlling the ignition timing and the intake air amount after the rapid heating control means;
- gradual control means for changing values provided by the rapid heating control means to values provided by the normal control means, wherein the gradual control means advances the ignition timing gradually and decreases the intake air amount simultaneously and gradually;
- racing detecting means for detecting a racing of the engine by monitoring at least one of the engine speed and an opening degree of the throttle valve;
- and
- quick control means activated instead of the gradual control means when the racing is detected, for changing the ignition timing and the intake air amount quickly from values provided by the rapid heating control means to values provided by the normal control means.
A method for controlling a catalyst temperature of an engine, the method comprising:
- accelerating a warming up of the catalyst by retarding an ignition timing and increasing an intake air amount;
- controlling the ignition timing and the intake air amount subsequent to the accelerating step;
- changing values gradually from values provided in the accelerating step to values provided in the controlling step by advancing the ignition timing gradually, and decreasing the intake air amount simultaneously and gradually;
- detecting a racing of the engine by monitoring at least one of the engine speed and an opening degree of the throttle valve;
- and
- changing values quickly from values provided in the accelerating step to values provided in the controlling step by advancing the ignition timing quickly, and decreasing the intake air amount simultaneously and quickly when the racing is detected.
Dependencies are inferred from the claim text.