Patent ID: 6904356
Filing Date: 2005-06-07
Classification: F02D,F02M,Y02T

Abstract:
1. An apparatus for estimating an internal EGR amount of an internal combustion engine, wherein the engine includes a cylinder accommodating a piston, an intake passage and an exhaust passage connected to the cylinder, an intake valve for selectively connecting and disconnecting the intake passage with the cylinder, and an exhaust valve for selectively connecting and disconnecting the exhaust passage with the cylinder, wherein the internal EGR amount is the amount of combusted gas that exists in the cylinder when air-fuel mixture is combusted in the cylinder, the apparatus comprising: a computer that computes the internal EGR amount as the sum of a remaining combusted gas amount and a backflow combusted gas amount, wherein the remaining combusted gas amount is the amount of combusted gas that exists in the cylinder immediately before the intake valve is opened, and the backflow combusted gas amount is the amount of combusted gas that flows back into the cylinder from the exhaust passage after the intake valve is opened.