Patent attributes
In an NOx discharge quantity estimation method for an internal combustion engine equipped with an EGR apparatus, the gas components (e.g., oxygen molecules and NOx) 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 NOxgenerated as a result of combustion remains in the region B after combustion, and NOx present in the region A before combustion due to circulation of EGR gas is conserved after combustion, the quantity of NOx discharged from the exhaust passage to the outside is calculated in consideration of not only the quantity of combustion-generated NOx in the region B but also the quantity of circulated NOx in the region A.
