Gasoline Direct Injection (GDI) is usually a type of fuel injection system that sprays gasoline straight into the combustion chamber. Like engines outfitted with Multiport Fuel Injection (MFI) techniques, there exists a separate fuel injector for every of your engine’s cylinders. But rather than mounting the injectors while in the intake manifold so the injectors spray fuel to the consumption ports in the cylinder head, the GDI injectors are mounted in the cylinder head and spray fuel to the combustion chamber. The fuel bypasses the intake valves totally and enters the combustion chamber being a higher pressure mist.

Large Stress Fuel Injection

Direct injection calls for particularly large operating pressures (as much as 2200 PSI) in comparison with typical multiport fuel injection systems that typically involve only 40 to 60 PSI. Direct injection needs a lot more delivery pressure to conquer compression stress inside the cylinder and also to delivery a higher volume of fuel in a shorter period of time.

With ordinary MFI fuel injection, the fuel is sprayed into the intake port that is beneath vacuum. The fuel mist is then drawn into the combustion chamber coupled with the incoming air, mixed collectively during the compression stroke, then ignited from the spark plug. With GDI, only air is drawn in to the cylinder through the consumption stroke. As the piston comes up over the compression stroke, fuel is injected to the cylinder prior to ignition. The timing of your injection will depend on engine speed, load and operating problems. In some circumstances (such as light cruise), fuel may possibly not be injected until finally the piston has virtually reached Top Dead Center on its compression stroke. Supplemental injection pulses of fuel might also be delivered once the initial mixture ignites to keep the flame burning over the power stroke.

Advantages of Gasoline Direct Injection

Spraying fuel right to the combustion chamber as compression is building, and throughout and after first combustion will allow the engine to produce far more power using significantly less fuel. Engines with GDI can tolerate incredibly lean fuel mixtures underneath light load and cruise disorders. The net result is typically 15 to 25 % improved fuel overall economy when compared to multiport fuel injection.

The capability to closely management the fuel mixture and give the engine just what it needs at just the ideal minute also implies GDI engines can handle increased static compression ratios. The Buick 3.6L V6 includes a compression ratio of 11.3 to one, which will help make improvements to combustion efficiency and power. GDI engines normally create far more horsepower than these with multiport injection techniques.

Gasoline Direct Injection Applications

Gasoline direct injection is employed on a range of late model engines: Audi, BMW, GM, Ford, Lexus, Mazda, MINI, Nissan, Porsche, VW and other people. Some recent domestic applications include things like Ford Ecoboost engines (which are also turbocharged) from the 2010 Focus & Edge and 2011 Explorer, and the DI 3.6L V6 engine inside the 2010 Buick LaCrosse and Enclave, 2010 Camaro and GMC Acadia.