Internal combustion engine with exhaust gas recirculation

摘要

An engine is described that has a variable valve timing system. Under low and medium load operation of the engine, the valve timing system sets an extended valve overlap period and fuel is injected predominantly during this extended overlap period either into the intake ports or directly into the combustion chambers. The effect is that the fuel is heated by the internally recirculated exhaust gases which pre-conditions the fuel to improve ignitability and combustion quality.