Patent ID: 6212884
Filing Date: 2001-04-10
Classification: F01N,F02D,Y02T

Abstract:
A device for controlling the rise of the catalyst temperature in an internal combustion engine comprising:a catalyst which is a three-way converter provided in an exhaust pipe of the internal combustion engine;a catalyst temperature pick-up means for picking up data corresponding to the temperature of the catalyst as catalyst temperature;a variety of sensors for detecting the operation conditions of said internal combustion engine;an air-to-fuel ratio control means for controlling the air-to-fuel ratio of the internal combustion engine depending upon the operation conditions;and an air-to-fuel ratio lean-correction means;wherein said variety of sensors detect at least intake-air-amount data corresponding to the load on said internal combustion engine and crank angle data corresponding to the rotational speed of said internal combustion engine; andwhen the temperature of said catalyst is lower than said predetermined temperature, said air-to-fuel ratio lean-correction means sets said target air-to-fuel ratio to a lean activating air-to-fuel ratio which is larger than an air-to-fuel ratio during the normally controlled operation and is higher than a stoichiometric air-to-fuel ratio, andwherein further said air-to-fuel ratio lean-correction means includes: a first comparator means for comparing said catalyst temperature with a first predetermined temperature near said activating temperature; anda second comparator means for comparing said catalyst temperature with a second predetermined temperature which is higher than said first predetermined temperature and corresponds to said activating temperature; andif said catalyst temperature lies within a range between said first predetermined temperature and said second predetermined temperature, said target air-to-fuel ratio is set to said lean activating air-to-fuel ratio.