Identification of fuel injection control system in a GDI engine

In 1995 as a first in the world Mitsubishi introduced SI engine with the direct fuel injection to combustion chamber GDI (Gasoline Direct Injection). Currently such a way of providing of gasoline is applied and introduced to mass production by other companies. This solution permits to burn stratified mixtures which is rich in the region of the spark plug and very lean in more distant areas of the combustion chamber. The average mixture composition of such a mixture is very poor and often incombustible. The combustion of lean mixture to some extend permits to reduce fuel consumption but limits also the possibility of reduction of NOx by the typical catalyst. Furthermore the direct injection of gasoline to combustion chamber gives the possibility of the precise dosage in each cycle. The precise control of mixture composition is possible because the injection of the fuel takes place after closure of inlet valve, so the amount of the air in the cylinder is known. The precise dosage and the dispersion of the fuel in connected with several problems. The additional information which is provided by sensors installed on the engine is very useful to solve. Gasoline direct injection fuel systems are equipped with sensors which aren't use in standard indirect systems. These problems are described in the paper with special attention paid on the accuracy of the dosage of the fuel and all problems related with this.