Apparatus for controlling air feeding to exhaust pipe of internal combustion engine

Claim 1

In an internal combustion engine equipped with an intake pipe and an exhaust gas purification/discharge system including an exhaust pipe and a catalytic converter installed in said exhaust pipe for purification of engine exhaust gas, an apparatus for controlling the introduction of air into said exhaust gas purification/discharge system to improve the efficiency of purification of exhaust gases, comprising: an air feed pipe having an inlet port and an outlet port which is connected to said exhaust pipe at a position upstream of said catalytic converter; electrically controllable valve means installed in said air feed pipe at a position downstream of said inlet port for controlling air flow fed to said exhaust gas purification/discharge system; electrical heater means disposed in said air feed pipe at a position downstream of said electrically controllable valve means and upstream of said catalytic converter; power supply means for supplying electric power required for operation at least of said engine, said valve means and said heater means; voltage level detector means for detecting an output voltage level of said power supply means; and control means electrically connected to said power supply means, said valve means, said electric heater means and said voltage level detecting means for electrically energizing said heater means upon a start of operation of said engine and for simultaneously controlling a timing of operation of said valve means to feed air to said exhaust gas purification/discharge system via said electric heater means in dependence upon the output voltage level of said power supply means as detected by said detector means.