Pm emission amount estimation device for diesel engine

Abstract

Providing a PM emission amount estimation device for the diesel engine wherein the accuracy of the correction in correcting the basic level of the PM emission amount by use of the PM emission amount estimation map can be enhanced; and, the PM emission amount particularly during the transient state of the engine operation condition can be accurately computed so as to estimate, with high precision, the PM emission amount and the PM emission accumulated-amount (integrated amount) during the whole engine operation conditions including the transient state as well as the steady state. A PM emission amount estimation device for estimating the amount of the PM for estimating the amount of the PM that is emitted from a diesel engine and collected by a DPF provided in the exhaust gas passage of the engine, the device including, but not limited to: a PM emission amount estimation base-mapwith which the base PM emission amount is computed in response to the operation condition of the engine; a PM emission amount estimation correction-mapthat determines a correction factor for correcting the base PM emission amount computed by the PM emission amount estimation base-map, the correction factor being determined in response to the transient engine operation condition; a transient state judgment devicethat judges that the engine is operated in a transient operation condition based on the change of the air excess ratio regarding the engine; a PM emission amount computation devicethat corrects the computed base PM emission amount by multiplying the computed base PM emission amount by the correction factor computed with the PM emission amount estimation correction-maponly in a case where it is judged, by the transient state judgment device, that the engine is in a transient operation condition whereas the base PM emission amount is directly outputted in a case where it is judged that the engine is in a steady operation condition.