Two Concepts of Pumping Fuel in a Gasoline Injector

In this paper, two concepts of fuel pumping methods using solenoid, for gasoline injection in engines, are discussed. The fuel pump is integrated within the injector in these concepts, which makes the fueling system, simple, compact and less expensive. This integrated gasoline pump injector (GPI) is aimed at catering to the upcoming stringent emission norms, as it enables the usage of closed-loop fuel correction with the help of an electronic control unit (ECU), based on the exhaust lambda feedback. A solenoid and spring arrangement is used in this injector design, where the fuel gets pressurized in a pumping chamber, and the pressurized fuel is then injected through orifices to produce spray in the intake port. Two concepts are used for pressurizing the fuel. First concept uses a spring to pump the fuel and a solenoid to retract the plunger. Second concept uses solenoid to pump the fuel and spring to retract the plunger. The magnetic and hydraulic behaviors of the injector are different in the studied cases and offers choice to choose the concept according to the application. The first concept relies on the spring for the injector’s hydraulic performance and control, whereas the second one relies on the solenoid. The solenoid responds faster than the spring, and by virtue of this, the second concept is seen more suitable for better hydraulic discharge control. The electromagnetic and hydraulic characteristics of both the concepts are studied using simulation and tests, and the results are presented in this work