Electronic fuel injection (EFI)

Electronic Fuel Injection (EFI) is a substitute for the conventional metering system which mixes the air and fuel in the correct ratio before feeding it down to the main cylinder to power the vehicle.

Usually in a bike a carburetor is responsible for carrying out this task. But, the downside of using a carburetor is that it has fixed settings and it has certain limitations. To overcome this negative aspect of a new system has been introduced. However, for this brand new system to work, it needs data from several sensors. These sensors include an engine speed sensor, temperature sensor, voltage sensor, throttle position sensor, oxygen sensor and an air flow sensor. The data collected from the various sensors are send to the Electronic control unit (ECU). The ECU makes use of the data provided from the sensors to determine the spark advance, the length of spark and other parameters. Then the exact air fuel mixture for that particular instant is fed into the cylinder which in turn delivers optimum power and clean exhaust. All this process is done continuously and happens many times in every second.

A cross section of a fuel injector is shown below:

Typical EFI components:

1)     Injectors

2)     Electronic control module (ECU)

3)     Fuel pressure regulator

4)     Fuel pump

5)     Wiring harness

6)     Sensors

Advantage:

1)        Although the electronic fuel injection is much more complicated than a carburetor, it is much more efficient.

2)     Fault finding is easy with the right tools

Disadvantage:

1)     Higher cost than carburetor.