Groupwise Fuel Injection system

Groupwise Fuel Injection system Introduction

The Groupwise Fuel Injection (GFI) system is essentially a simplified version of the MPI system. The major difference between them is the methods that they each employ to control their injectors. In an MPI system, the injection timing for each injector is controlled individually. GFI systems, on the other hand, control the timing for two different injector groupings, i.e., injectors No.1 and No.4 are controlled together, as are injectors No.2 and No.3. Please refer to the following diagram.

When a TDC signal is received by the ECM, injectors No. 1 and No. 4 are activated together. Then, when the second TDC signal from the above signal is received, injectors No. 2 and No. 3 are activated. In other words, the No. 1 and No. 4 injector group and the No. 2 and No. 3 injector group are alternately activated by every other TDC signals.

As you can see from the diagram, fuel is not always injected before the cylinder’s intake stroke. The fuel injected in other strokes is taken in these cylinders in the following intake strokes after injection. The GFI system controls the injection to the extent that the fuel is injected for each cylinder once in a combustion cycle-or in four cylinder strokes.

The only control signal required in this system is the signal from a TDC sensor. Cylinder position sensors and crankshaft position sensors used in Multi-Point Fuel Injection (MPI) system are not needed.

Apart from the above, all other components and control methods are more or less the same as those used in MPI systems.