Abstract: An exhaust purifier for an internal combustion engine is capable of properly heating a catalyst in consideration of a deterioration with time and manufacturing variation in an electric heater that heats the catalyst.The exhaust purifier has the catalyst 4 disposed in an exhaust pipe, the electric heater for forcibly heating the catalyst 4, a power source for supplying power to the heater, an estimate unit for estimating the temperature that the catalyst 4 will reach, a comparator for providing the difference between the estimated temperature and a target temperature, and an operation controller for controlling the operating conditions of the engine according to the temperature difference. The estimate unit measures the voltage and current of the heater, calculates the resistance or power of the heater according to the voltage and current, and estimates the temperature.

Abstract: An exhaust purifier of an internal combustion engine supplies secondary air into an exhaust pipe without cooling nor inactivating an electrically heated catalyst (EHC) that is active. The exhaust purifier includes the EHC 3 disposed in the exhaust pipe 2, a main catalyst 4 disposed in the exhaust pipe 2 downstream from the EHC 3, and a unit for supplying secondary air into the exhaust pipe 2. The secondary air supply unit has a main path 10 for supplying secondary air into a space defined in the exhaust pipe 2 between the EHC 3 and the main catalyst 4 when it is determined that the main catalyst 4 is active. The secondary air supply unit may additionally have a second path 9 for supplying secondary air into the exhaust pipe 2 on the upstream side of the EHC 3 when it is determined that the EHC 3 is active, so that the secondary air may pass through the EHC 3 and reach the main catalyst 4.

Abstract: An onboard load control apparatus and a method for detecting a fault of an onboard electrical load with high accuracy are disclosed. The control apparatus comprises an onboard battery mounted on an automotive vehicle, an electrical heater for electrically heating an electrical load such as an electrically-heated catalyst supplied with power from the onboard battery, an auxiliary relay for turning on/off the power to the electrical heater from the onboard battery, and an ECU for controlling the on/off operation of the auxiliary relay. The apparatus further comprises an engine speed detector for detecting the engine speed of the internal combustion engine and a fault judgement unit for judging whether the electrical heater is normal or faulty on the basis of the fluctuation amount of the engine speed of the internal combustion engine detected by the engine speed detector before and after switching the auxiliary relay.