Gasoline engines

The 1970s saw the beginning of a tightening up of exhaust-emission limits for motor vehicles all over the world. Catalytic exhaust-gas purification helped to keep
emission values within the new limits.

Even more effective purification was achieved by the introduction of lambda regulation: the lambda oxygen sensor measures the oxygen content in the exhaust gases. The A/F mixture preparation unit regulates fuel supply to the engine in accordance with the signal from the lambda sensor. The aim of lambda regulation is always to achieve a stoichiometric air/fuel ratio of (l = 1).