Patent ID: 6052988
Filing Date: 2000-04-25
Classification: F01N,H02J,Y02A,Y02T

Abstract:
An apparatus for controlling the supply of electric power from a power source to an electrically heated catalyst to electrically heat the catalyst carrier attached to the exhaust gas passage of an internal combustion engine, comprising:a power source circuit-switching means disposed between said power source and said electrically heated catalyst;a start detection means for detecting the start of said engine;a time counting means for counting the passage of time from the starting of said engine;a resistance detection means for detecting the electric resistance of said electrically heated catalyst;first electric power supply control means for turning said switching means on simultaneously with starting of said engine and for feeding a maximum permissible electric power from said power source to said electrically heated catalyst;second electric power supply control means for interrupting the supply of electric power from said power source by said first electric power supply control means when the lapse of time from starting of said engine has reached a first predetermined period of time just before said catalyst is activated and, then, controlling the supply of electric power by feedback through said switching means based upon said electric resistance so that the resistance is maintained at a predetermined resistance; anda power supply interrupt means for interrupting the supply of electric power from said power source to said electrically heated catalyst when the lapse of time from starting of said engine has reached a second predetermined period of time which is long enough for activating said catalyst.