EXHAUST GAS PURIFICATION APPARATUS AND METHOD FOR INTERNAL COMBUSTION ENGINE

摘要

An objection is to provide exhaust gas purification apparatus and method for an internal combustion engine, which can initialize a SCR catalyst by heating the SCR catalyst under predetermined conditions without accompanying troublesome procedures and complicated calculations. With the exhaust gas purification apparatus for an internal combustion engine, arranged on an exhaust-gas passage of the internal combustion engine and including the SCR catalyst for purifying NOx in exhaust gas in the internal combustion engine, the method executes the steps of calculating and accumulating estimate value of the amount of NH3 adsorption adsorbed on the SCR catalyst, on the basis of the amount of NH3 injection produced from urea-aqueous solution injected into the exhaust-gas passage from the upstream side of the SCR catalyst and the amount of NH3 injection for purifying NOx at the upstream side of the SCR catalyst, and initializing the SCR catalyst by heating the SCR catalyst to initialize the estimate value of the amount of NH3 adsorption.

主权项

1. An exhaust gas purification apparatus for an internal combustion engine, comprising:
an SCR catalyst for purifying NOx in exhaust gas of the internal combustion engine, disposed on an exhaust-gas passage of the internal combustion engine; and an exhaust gas purification controller part including a NH3 adsorption calculation part to calculate an estimate of an amount of NH3 adsorption which is to be adsorbed on the SCR catalyst, on the basis of an amount of injection of NH3 produced from urea-aqueous solution injected into the exhaust-gas passage from an upstream side of the SCR catalyst and an amount of NH3 for purifying NOx at the upstream side of the SCR catalyst, a NOx estimate derivation part to derive an estimate of an amount of NOx at a downstream side of the SCR catalyst on the basis of the estimate of the amount of NH3 adsorption from the NH3 adsorption calculation part and a temperature of the SCR catalyst, and a SCR catalyst heating command part to heat the SCR catalyst to initialize the amount of NH3 adsorption of the SCR catalyst on the basis of an error between the estimate of the amount of NOx from the NOx estimate derivation part and a measurement of the amount of NOx at the downstream side of the SCR catalyst.