Systems and methods for estimating residual gas fraction for internal combustion engines using altitude compensation

Abstract

An engine control system comprises a first factor calculating module that calculates a first factor based on intake cam position (ICAM), exhaust cam position (ECAM), engine speed (RPM) and first calibration factors. A second factor calculating module calculates a second factor based on ICAM, ECAM, RPM and second calibration factors. A residual gas fraction (RGF) estimating module estimates a RGF value based on the first factor adjusted for altitude and said second factor. A method comprises calculating a first factor based on intake cam position (ICAM), exhaust cam position (ECAM), engine speed (RPM) and first calibration factors; calculating a second factor based on ICAM, ECAM, RPM and second calibration factors; and estimating a residual gas fraction (RGF) value based on the first factor adjusted for altitude and said second factor. At least one engine operating parameter is adjusted based on the RGF value.

Dependencies are inferred from the claim text.