Exhaust gas-purifying system for internal combustion engines

摘要

An exhaust gas-purifying system is provided for an internal combustion engine for use in a vehicle having an alternator driven by the engine to generate electric power. An electrically-heated catalyzer is arranged in the exhaust system of the engine and connected to the alternator to be electrically heated thereby. A changeover switch is provided for selectively switching the destination of electric power generated by the alternator to the electrically-heated catalyzer and to the electrical equipment. An ECU controls the electric power generated by the alternator, depending upon a direction in which the changeover switch has been switched. The ECU detects abnormality of the changeover switch, and when the abnormality is detected, the electric power generated by the alternator is changed to a value smaller than a value assumed when the changeover switch is normal.