Apparatus for controlling power supplied to an electrically heated catalyst attached to an exhaust gas passage of an internal combustion engine

Abstract

When an apparatus for supplying power to an EHC becomes faulty, the supply of power to the EHC is shut off by a means which is separate from a control relay to prevent the catalyst from being overheated. The control relay that is opened and closed by an ECU is provided in a circuit that supplies electric power from a power source to the EHC attached to an exhaust gas passage of an internal combustion engine, and power supplied to the EHC is controlled by the control relay. When the control relay is short-circuited, this short-circuiting fault is detected by some means, and the power supply circuit is forcibly shut off so that power will not be continuously supplied to the EHC from the power source in this state. Means for forcibly shutting off the power supply circuit may be a relay, a breaker or a fuse when the power source is a battery, and may be to suppress the amount of power generated by an alternator when the power source is the alternator.

Dependencies are inferred from the claim text.