GDI (Gasoline Direct Injection)

What is GDI?

Professional Automotive Answer:
GDI stands for Gasoline Direct Injection. It’s a type of fuel injection that more and more manufacturers are using these days. It’s different from the normal port fuel injection you may be more familiar with.

Port Fuel Injection uses a small port on the outside of the cylinder on the engine.
It works a little like this. Fuel is injected, at a determined amount by the computer, into the air intake system. It is made available to the outside of the intake valve. When the intake valve opens the fuel is drawn into the combustion chamber and ignited by the spark plug. The burning process of the fuel shoves the piston down creating power to spin the engine.

The Gasoline Direct Injection process is a little different:

You wont find a port for fuel to spray in this engine. In a GDI engine the intake opens and draws air in the combustion chamber to compress it. Then at the right time, which is determined by the computer, an injector sprays fuel directly into the combustion chamber then it is ignited by a spark plug to burn the fuel.

Why switch to a GDI? When trying to meet the ever increasing cafe standards enforced upon the auto makers they are having to always try to come up with new ways of squeezing more and more mileage out of every drop of fuel. The GDI system allows for more precise fuel control and delivery. With the fuel being directly sprayed in the combustion chamber area, it allows for more power and better fuel economy.

Normally fuel injectors need about 46 to 65 psi of fuel pressure to make them operate. The GDI fuel injectors will require upwards of 2000 psi. They require more pressure because they have to over come the high pressures of the combustion chamber.

This brings up some maintenance issues. Intake valves build up carbon deposits over time and some of this gets cleaned off in a port injected engine because the fuel flows over the valves and washes it away. With a GDI engine this doesn’t occur because the fuel is directly injected into the engine. So pouring a bottle of fuel system cleaner in the fuel tank will not reach the back side of the valves in your engine. A professional cleaning at Professional Automotive will keep those valves clean and keep your GDI engine operating efficiently.

GDI will continue to be more prevalent in the Indianapolis, Castleton, and Fishers area on everything from compact cars to pick-up trucks. Ask your Professional Automotive service adviser if your car could benefit from a fuel system cleaning.

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Professional Automotive
7013 E 86th St
Indianapolis, IN 46250