Key Factors of Fuel Injection System to Draw Out Good Response in 4-Valve Engine

Fuel and air behavior in the induction passage of a 4-valve engine were investigated in order to improve response at low and medium engine speeds.

It was found that response is affected not only by wall vetting but also by fuel being pushed back into the intake manifold and by a lack of fuel which occurs during the transient.

Futhermore, fuel-air mixing was found to be insufficient at certain injection timings, resulting in poor combustion and a consequent increase in exhaust emission and fuel consumption.

This paper describes the factors of the fuel injection system which are critical for optimum response. Recommendations are made for injector location and injection timing and a proposal is put forward for a system of compensatory fuel injection to improve combustion efficiency during acceleration.