The fuel injection system for each cylinder comprises at least two injection periods for each cylinder; an initial period and a secondary period. As soon as the injection control receives a torque reduction signal, eg. from an ASR control, the fuel injection rate for each cylinder is started from the next initial injection period. This ensures that each full injection cycle satisfies the optimum burn conditions for the engine. If the torque reduction command is generated between the injection periods of a particular cylinder then the application of the reduction command is deferred to the next full cycle. The control system also monitors the temperature of the catalytic converter, to ensure it does not exceed the operating range.
