18 February 2016

Gasoline Direct Injection Engine | Advantages | Applications

In GDI fuel injection system is direct sprays gasoline into the combustion chamber.

GDI is an advanced injection system for gasoline engines that thanks to high operating pressures and multi-point injection combined with turbocharger allow engine downsizing.

GDI improved performances, and significant reductions in fuel consumption and emissions.

Petrol is injected directly into the cylinder as opposed to the more common petrol injected car where petrol is injected into the airflow prior to it reaching the cylinder.

In GDI engine fuel delivery is an important component. There is standard type electric fuel pump immersed in the fuel tank this pump delivers it to a mechanical pump which is increased pressure that is delivered to the injectors.

As per Mitsubishi, their GDI engines can burn fuel 35 per cent to 40 per cent more efficient than an engine with MPFI technology used and same time also increased power output by about 10 per cent.

This is a technology that originated from mass production and has already been applied in the Motorsport and in 2014 will also be used in Formula 1  for this racing application, Magneti Marelli is currently testing injectors and pumps for engines with petrol pressures of up to 500 bar.

Advantages of Gasoline Direct Injection :
  • Produce more power using less fuel. 
  • Tolerate extremely lean fuel mixtures (40:1) under light load 
  • 15 to 20 % better fuel economy compared to MPFI systems.
  • GDI engines can handle higher static compression ratios
  • Improve combustion efficiency and power. 
  • GDI engines produce more horsepower than MPFI systems full form is multi-point fuel injection system.
Disadvantages of Gasoline Direct Injection :

GDI fuel is directly injected in the combustion chamber layer of carbon deposits on the intake valve. As the deposits build up on the valve face, they may prevent the intake valves from sealing causing a compression leak, loss of power. 

Heavy carbon accumulations on the intake valves can also restrict airflow, hurt power at higher engine speeds and cause a drop in fuel economy and performance. 

If the engine is equipped with a turbocharger, there is a chance the carbon could damage the turbine fins in the turbocharger. 

Because of diesel injection, the fuel has less time to mix with the incoming air before it ignites.

Gasoline Direct Injection Applications :

Gasoline direct injection is used on a variety of late-model engines: Audi, BMW, GM, Ford, Hyundai, Kia, Lexus, Mazda, MINI, Nissan, Porsche, VW and others. 

By 2016, almost half of all new vehicles sold in the U.S are predicted to have gasoline direct injection engines.