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How Does Fuel Injection Work?


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Multi Port Fuel Injection
Fuel rail style fuel injection.

This is a fuel rail.

courtesy Bosch USA
Multi-port injection is still widely in use today. So far it's the most efficient method of metering gas into the engine. Multi-port fuel injection, also known as MFI, consists of an injector for each cylinder in the engine. This injector sprays fuel directly through the intake valve or valves into the combustion chamber. Each injector is activated separately by wire. Early versions of this system, such as CIS, Jetronic and Motronic utilized a fuel distributor that metered fuel to the injectors through separate fuel lines. Later versions utilize a single fuel line that connects to a fuel rail on top of the engine. The injectors take gas from the central fuel rail and squirt it into the engine when told to do so.
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  5. Multi Port Fuel Injection With Multiple Injectors

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