NOx DISCHARGE QUANTITY ESTIMATION METHOD FOR INTERNAL COMBUSTION ENGINE

摘要

In an NOSUBx /SUBdischarge quantity estimation method for an internal combustion engine equipped with an EGR apparatus, the gas components (e.g., oxygen molecules and NOSUBx/SUB) of intake gas taken into a combustion chamber are assumed to be uniformly distributed throughout the entire region of the combustion chamber. Under such assumption, the combustion chamber is divided into a combustion region (region B) and a non-combustion region (region A) by making use of the ratio of the "mass of oxygen consumed as a result of combustion" to the "total mass of oxygen taken in the combustion chamber." Further, under the assumption that NOSUBx/SUBgenerated as a result of combustion remains in the region B after combustion, and NOSUBx /SUBpresent in the region A before combustion due to circulation of EGR gas is conserved after combustion, the quantity of NOSUBx /SUBdischarged from the exhaust passage to the outside is calculated in consideration of not only the quantity of combustion-generated NOSUBx /SUBin the region B but also the quantity of circulated NOSUBx /SUBin the region A.