Closed Loop Fuelling: Notes

The ECM uses a closed loop fuelling system as part of its fuelling strategy. The operation of the three-way catalytic converter relies on the ECM being able to optimize the air/fuel mixture, switching between rich and lean either side of lambda one. Closed loop fuelling is not standard for all markets, vehicles that are not fitted with HO2S do not have closed loop fuelling.

The ideal stoichiometric ratio is represented by lambda = 1. The ratio can be explained as 14.7 parts of air to every 1 part of fuel.