A method of controlling injection of an internal combustion engine

The invention concerns a method which consists in placing two sensors (SD1, SD2) upstream and downstream of the catalyst container (CAT). When the downstream sensor (SD2) supplies a richness condition of the injected mixture, different from the richness condition supplied by the upstream sensor, the method consists in correcting the amount of fuel injected based on the downstream sensor alone, except if the latter is stoichiometric condition, in which case a double corrective loop of richness is carried out.