Patent ID: 6334305
Filing Date: 2002-01-01
Classification: F02D

Abstract:
A self-adapting method of controlling titre for an internal combustion engine (2) provided with a system for reducing pollutant emissions (4) and first and second sensor means of stoichiometric composition (5, 6) disposed respectively upstream and downstream of this system for reducing pollutant emissions (4) and respectively adapted to generate an upstream composition signal (V1) and a downstream composition signal (V2), this method comprising the stages of:a1) determining a correction coefficient (KO2) as a function of the upstream composition signal (V1), the downstream composition signal (V2) and an objective signal (VÂ°) indicative of an objective exhaust titre; a2) determining an operating quantity of fuel (QF) to be injected into each cylinder of the engine (2) as a function of this correction coefficient (KO2); characterized in that it further comprises the stages of: b) storing a plurality of current values (VAC(i,j)) of an adaptation signal (VA), each associated with a respective combination of values of the number of revolutions (RPM) and the load (L) of the engine (2); c) updating these current values (VAC(i,j)) as a function of the downstream composition signal (V2); d) selecting, on each engine cycle, a current value (VAC(i,j)) corresponding to the number of revolutions (RPM) and the load (L) of the engine (2) in this engine cycle; e) generating this adaptation signal (VA) as a function of the current value (VAC(i,j)) selected; and that the stage a1) further comprises the stage of: a11) determining the correction coefficient (KO2) also as a function of this adaptation signal (VA); and wherein stage c) is preceded by the stages of: f) checking the permanence of this downstream composition signal (V2) in a dead band (BM) (140); g) carrying out an updating procedure in the dead band (150) when the permanence of the downstream composition signal (V2) in this dead band (BM) has been verified; h) carrying out an updating procedure outside the dead band (160) when the permanence of this downstream composition signal (V2) in the dead band (BM) has not been verified.