METHOD OF ESTIMATING RESIDUAL EXHAUST GAS CONCENTRATION IN A VARIABLE CAM PHASE ENGINE

摘要

A method of estimating the concentration of residual exhaust gas in an internal combustion engine having variable cam phase control is based on engine dynamometer and engine simulator data. Since both the volumetric efficiency and the residual exhaust gas concentration of an engine vary monotonically in response to changes in cam phase, the simulated residual concentration data is deemed to be reliable if the simulated volumetric efficiency data matches volumetric efficiency data determined by engine dynamometer testing. Volumetric efficiency test data is compared to simulated volumetric efficiency data, and the simulation software is tuned until the simulated data matches the test data. At such point, the simulated residual concentration data is deemed to be reliable, and is used to calibrate a model relating residual concentration to cam phase angle, and such model is then used by an engine controller (ECM) to estimate residual gas concentration during operation of the engine (10).