TEMPERATURE SENSOR PLAUSIBILITY DIAGNOSIS UNIT AND PLAUSIBILITY DIAGNOSIS METHOD AND INTERNAL COMBUSTION ENGINE EXHAUST PURIFICATION APPARATUS

摘要

To provide a temperature sensor plausibility diagnosis unit and plausibility diagnosis method that can accurately perform plausibility diagnosis of a temperature sensor in a desired timing and an exhaust purification apparatus equipped with the plausibility diagnosis unit.;A temperature sensor plausibility diagnosis unit which, in an exhaust purification apparatus of an internal combustion engine that delivers an additive inside a storage tank to an exhaust pipe on the upstream side of a reduction catalyst and selectively reduces and purifies NO_x in exhaust with the reduction catalyst, is for performing plausibility diagnosis of a temperature sensor disposed inside the storage tank, the temperature sensor plausibility diagnosis unit being equipped with an additive heat capacity calculating portion that calculates the heat capacity of the additive inside the storage tank, a heat quantity variation calculating portion that calculates an increase or decrease in the quantity of heat that the additive inside the storage tank receives, and a plausibility diagnosing portion that determines the plausibility of the temperature sensor by comparing an estimated temperature course of the additive estimated from the heat capacity of the additive and the increase or decrease in the quantity of heat with a sensor temperature course of the additive detected by the temperature sensor.