Internal combustion engine with exhaust gas recycling system

Abstract

An internal combustion engine and method of operating it that improves combustion efficiency, fuel economy and exhaust emission during low speed running. The engine is equipped with a relatively conventional main induction system and an auxiliary induction system having a substantially smaller cross sectional area for delivering a charge to the chambers of the engine at a high velocity to improve turbulence and combustion efficiency. A control valve arrangement is incorporated so that the idle and low speed requirements are supplied through the auxiliary induction system and the medium and higher load charge requirements are supplied primarily through the main induction system. An exhaust gas recirculating system is incorporated for reintroducing exhaust gases to the combustion chamber so as to reduce the emissions of nitrous oxide. A control arrangement is incorporated so that the exhaust gases are recirculated only at the time when the auxiliary induction system is supplying the primary portion of the charge requirements. A fuel enrichment system is also incorporated for providing a richer than normal fuel air-mixture at such time as exhaust gases are being recirculated. An arrangement is also incorporated for advancing the spark ignition at the time the exhaust gases are being recirculated and when the main induction system begins to supply a large portion of the engine charge requirements.