Modeling and Programming for a Computer Controlled Direct Gasoline Fuel Injection System of SI Engine

A computer controlled direct gasoline fuel injection (DGI) system has been modeled, programmed and constructed for a four-stroke SI engine. Locally available materials have been used for this experimental model. All the old model vehicle were equipped with carburetor for air fuel mixing and later on electronic fuel injection system has been introduced for maintaining better air fuel ratio and mixing in many late model vehicles. Later on Japan introduced direct gasoline fuel injection system in their SI engine but it is not yet commercialized in many under developed countries. Direct gasoline fuel injection (DGI) system has the advantage of fulfilling proper air fuel ratio in various operating conditions and loads providing minimum air pollution. In four stroke engine, fuel needs to be supplied once in every two revolution. A logic control and program is necessary to control and supply fuel supply once in the cylinder at every two revolution. A program has been made to control the system. Fuel injection period was maintained by opto-isolator sensor in this model. But fuel injection period need to be varied depending on operating condition and loads. Further research is necessary to develop this model and program depending upon engine loads. The designed DGI system is found to work properly with the designed constant speed of 3000 rpm. The development of this model with variable speed and load is necessary for improvement of vehicle performances and emission control.