Patent ID: 6422000
Filing Date: 2002-07-23
Classification: F02D

Abstract:
A method for controlling the composition of exhaust gases and for estimating a temperature of the exhaust gases at a location upstream from a pre-catalyser (2) disposed along an exhaust pipe (7) of an internal-combustion engine (20), which is provided with a system (1) for controlling said composition of the exhaust gases which comprises oxygen sensor means (10) disposed along said exhaust pipe (7) upstream from said pre-catalyser (2), heater means (11) associated with said oxygen sensor means (10), and means (12, 13, 15, 16) for piloting the heater means (11); the method comprising the steps of:(a) determining a first operative quantity (VPEFF) which is correlated to the exchange of heat between the oxygen sensor means (10) and the exhaust gases and determining a second operative quantity (VPEFF) which is correlated to an electrical power (WE) dissipated by the said heater means (11) to maintain an operative temperature (TS) of the oxygen sensor means (10) which is close to a target temperature (TO); wherein the determination of the first operative quantity (VPEFF) includes determining the operative temperature (TS) of the oxygen sensor means (10) and generating a pilot signal (VP) for the heater means (11) according to the operative temperature (TS) determined and the target temperature (TO); and (b) determining a temperature (TG) of the exhaust gases upstream from the pre-catalyser (2) according to the first operative quantity (VPEFF); wherein said determination of the temperature (TG) comprises determining the temperature (TC) of the exhaust gases upstream from the pre-catalyser (2) according to the piloting signal (VP).