Development of Direct Injection Gasoline Engine

A new 2.0 ℓ DOHC 4-valve direct injection (DI) gasoline engine has been developed which features new technologies such as swirl intake ports to produce an optimum swirl in the cylinder by variable controlled swirl control valve, pistons with a concave combustion chamber, and high pressure fuel injection system to provide a fine fuel-air mixture cloud in the combustion chamber. These all help to control fuel-air mixture preparation and flame propagation under ultra lean, stratified combustion at partial loads. NOx emission is reduced by using an electrically controlled EGR system and an NOx storage-reduction catalyst. At higher loads, a homogeneous mixture is obtained with direct injection during the intake stroke. A seamless output torque transition between stratified charge and homogeneous charge condition is achieved by an electronic throttle control system.

It has been confirmed that a vehicle with this system successfully improves fuel economy while satisfying emission requirements.