EFi, MPFi, GDi

EFi vs MPFi vs GDi: How Electronic Fuel Injection Technology Works?


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EFi, MPFi, GDi -

EFi stands for Electronic Fuel injection (EFi) whereas MPFi or MPi stands for Multi-Point Fuel injection and GDi stands for Gasoline Direct Injection. All these are the types of fuel injection systems which the gasoline or petrol fuel engines mainly use. All these terms refer to the newer generation Petrol Injection systems.

Earlier, older engines used simple Fuel Injection (Fi) which replaced the carburetor to overcome some of its shortcomings. The carburetor, being a mechanical device, was just not fully capable of controlling an accurate air-fuel ratio to meet the growing demands for better emission control.



Hence, it was replaced with first generation Fuel Injection technology. In this method, the petrol fuel is atomized by forcing it thru’ an injector as opposed to its suction created in a venturi tube in a carburetor which lifts the petrol thru’ its orifices. Thus, there is a fundamental difference between the earlier generation carburetor & newer generation Fuel Injection (EFi) system.

Earlier, the first generation Fuel Injection featured a simple design which consisted of an injector and a mechanical fuel pump. Basically, the fuel pump provided sufficient pressure to open the injector hydro-mechanically. Later, this system was upgraded to include electrically operated Injector by an ECU which is the first generation Electronic Fuel Injection systems or EFi.



Throttle Body Injection (TBI) -

Throttle Body Injection is also known as Central Fuel injection system. It consists of an electrically controlled fuel injector placed above the butterfly valve (throttle) and sprays fuel into the throttle body.

1st Generation EFi - Throttle Body Injection System - TBi
1st Generation EFi - Throttle Body Injection System - TBI

Single-Point Fuel Injection –

Single Point Fuel Injection is the second generation Fuel Injection system which used electronically controlled Fuel Injection (EFi). Furthermore, it governed the injection timing accurately with the help of an ECU, sensors, and actuators. It used a ‘common-to-all-cylinders’ injector which supplied petrol in atomized form.

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