Electronic fuel injection is standard in cars, but which variety is better, direct injection or port injection?
For many car manufacturers, there isn’t a clear winner, so they have begun to use both types in some models. Both methods have clear advantages and disadvantages but what is the difference between them? And how does combining them affect vehicle performance?
All these questions and more are answered in this video from Engineering Explained. First thing first is to understand the difference between port and direct injection.
Port injection sees the fuel injected before the intake valve whereas direct injection sees the fuel injected directly into the cylinder. For the fuel to combust, it needs first to vaporize, each method of injection has a slightly different approach to getting this done. With port injection, the fuel is at low pressure when it arrives, but has a lot of time for it to mix with the air.
From the time it is added to the intake runner and during both the intake stroke, compression stroke. With direct injection, the timing of when it is added to the chamber changes from engine to engine, but in any case, there is less time for the fuel to mix with the air.
To overcome this, the fuel is added at a higher pressure to create a fine mist that can more easily vaporize. Now you know the basics watch the rest of this educational video to truly understand the good the bad and the ugly of electronic fuel injection.
