Supercharged internal combustion engine

摘要

The supercharged internal combustion engine is so adapted as to set the air-fuel ratio to become a lean air-fuel ratio which is leaner than stoichiometric and lean enough to maximize improvements in a rate of consumption of fuel, for example, to the A/F ratio of 16, when the supercharger exists in such a supercharging region as demonstrating its sufficient degree of supercharging capability. When the air-fuel ratio is made lean in the supercharging region, exhaust gases are recirculated into the intake system of the engine, in addition to a mixed fuel. Preferably, the exhaust gases having lower temperatures are recirculated at the time of a high load of the engine in the supercharging region, while the exhaust gases having higher temperatures are recirculated at the time of a low load of the engine therein.