22 March 2018

Common rail fuel injection system

Nowadays in automobile industries the use of common rail fuel injection system increasing in diesel engines as it has the potential to drastically cut emissions and fuel consumption. 

In the diesel engine :

This technology generates an ideal swirl in the combustion chamber. The new CRDi engine cuts the fuel consumption by 30% and doubles torque at low engine speeds and increases power by 25%. 

This system also brings a significant reduction in noise and vibrations of conventional diesel engines. In emission, greenhouse gases are reduced by 30%. At a constant level of NOx, CO ( Carbon Monoxide ) emissions are reduced by 40% and unburnt hydrocarbons are by 50% and also particulate emissions by 60%. 

In petrol engine :

Petrol engine using a carburettors for the supply of fuel-air mixture before the introduction of the MPFI system. Full form of MPFI is a multi-point fuel injection system. But nowadays carburettors are used for its simplicity and low cost. CRDI principles can be applied to this engine also. 

Some features of common rail fuel injection system :
  • The very high injection pressure of the order of 1500 bar.
  • Complete control over start, and end of injection. 
  • Injection pressure is independent of engine speed. 
  • Ability to have a pilot, main and post-injection.
  • Variable injection pressure.