Patent ID: 7051516

Claim:
Method for controlling a temperature of a catalyst system located in an exhaust duct of an internal combustion engine of a motor vehicle, the catalyst system comprising at least one primary catalyst and optionally one or more pre-catalysts catalysts, the method comprising: suppressing an overrun fuel cutoff at an operating point where a desired driving torque requested by a driver is smaller than an overrun torque of the vehicle (overrun phase τ s ), for maintaining temperature of at least one of the catalyst system and exhaust gas below predetermined value, by supplying the internal combustion engine with an air-fuel ratio (λ) having a value smaller than or equal to 1.1, wherein the suppressing of the overrun fuel cutoff in the overrun phase (τ s ) includes performing at least one of the following measures defining the air-fuel ratio (λ) applied during the overrun phase (τ s ) as a function of a measured or calculated temperature of at least one of the exhaust gas and the catalyst system, and at least partially compensating a useful torque produced by the suppression of the overrun fuel cutoff during the overrun phase (τ s ) by retarding an ignition point.