Patent ID: 6658364
Filing Date: 2003-12-02
Classification: F02D

Abstract:
A method of estimating gas pressure in an exhaust manifold of an internal combustion engine, where gases in the exhaust manifold are released to the atmosphere through an exhaust system coupled to the exhaust manifold, the method comprising the steps of:empirically determining and storing ratios of atmospheric gas pressure and exhaust manifold gas pressure corresponding various values of the quantity [(MAFes*(R*Tem)1/2)/(Aes*Pbaro)], where MAFes is a mass air flow of gas through said exhaust system, R is a gas constant, Tem is a temperature of gas in said exhaust system, Aes is an effective area of said exhaust system, and Pbaro is an atmospheric pressure; computing a value of [(MAFes*(R*Tem)1/2)/(Aes*Pbaro)] during operation of said engine, based on operational values of MAFes, Tem and Pbaro; retrieving an empirically determined and stored ratio of atmospheric gas pressure and exhaust manifold gas pressure corresponding to said computed value; and estimating the gas pressure in the exhaust manifold by applying the operational value of Pbaro to the retrieved ratio.