Regulating fuel-air mixture of IC engine after over-run - registering over-run and enriching mixture for controlled period afterwards to compensate for excess oxygen referenced by upstream exhaust probe

摘要

The method of regulating the fuel/air mixture of an IC engined (1) vehicle equipped with stoichiometric mixture control and catalytic converter (7) modifies the mixture setting after an over-run travelling downhill with fuel off. On returning to normal drive the mixture ratio is temporarily enriched to compensate for the excess oxygen content of exhaust emission generated by the over-run with beneficial effect to the converter (7) efficiency. A controller (9) responding to sensors for air intake (4), rpm. (2) and an exhaust probe (8) upstream of the converter (7) determines the fuel injection (3) duration (ti) for the relevant operating condition. ADVANTAGE - Prevents over-compensation of conventional systems after over-run periods caused by delayed response of exhaust probe placed downstream of converter. Eliminates generation of excess nitrogen oxides and hydrocarbon emissions at end of over-run.