1 ‘Common Rail Direct Injection’ is a type of advanced technology used in engine fuel systems.
2 The term ‘CRDi’ is most commonly referred to diesel engines. Quite similar technology is also used in petrol engines and the same is differentiated by classifying it as Gasoline Direct Injection (GDI) or Fuel Stratified Injection (FSI). Although both these technologies have a similarity in design as they consist of a common “fuel-rail” to supply fuel to injectors, they considerably differ from each other in pressures & type of fuel used.
3 In Common Rail Direct Injection, commencement of combustion takes place directly into the main combustion chamber located in a cavity on the top of the piston crown. Today, CRDi technology is being widely used to overcome some of the deficiencies of conventional DI engines which were sluggish, noisy and poor in performance when implemented especially in passenger vehicles.
4 The CRDi technology works in tandem with the engine ECU which gets inputs from various sensors to calculate precise quantity of fuel and timing of injection. In CRDi, the fuel system components are more intelligent which are controlled electrically / electronically.
5 The conventional injectors are replaced with advanced electrically operated solenoid injectors. Injectors are opened with an ECU signal depending upon the variables such as engine speed, load, engine temperature etc.
6 In a Common Rail system, A ‘common-for-all-cylinders’ fuel-rail or in simple words a fuel distribution pipe is used to maintain optimum residual fuel pressure and acts as a shared fuel reservoir for all the injectors.
7 The fuel is constantly supplied at the required pressure for injection.
8 In modern day engines, high pressure fuel is stored in this single tube which then supplies it to the solenoid valve injectors as opposed to the fuel injection pump supplying diesel thru’ independent fuel lines to injectors in earlier generation designs.
Components of CRDi System
1. High Pressure Fuel Pump
2. Common Fuel Rail
3. Injectors
4. Engine Control Unit
Working of CRD i
Pressure generation takes place in the high-pressure pump. The pump compresses the fuel at the pressures at about 1,000 bar or about 15,000 psi. It then supplies the fuel via a high-pressure pipe to the inlet of the rail. From there, the fuel is distributed to the individual injectors, which inject it into the cylinder’s combustion chamber.
Most modern diesel engines use Common Rail with Unit-Injector system combined with a Turbocharger to achieve increased power output and meet stringent emission norms. This helps to improve engine power, throttle response, fuel efficiency and control emissions. Barring a few design changes, the basic principle & working of the CRDi technology remains primarily the same across the board. The manufacturers use custom acronyms to make their diesel CRDi product stand out in the competition.
source: https://crankit.in
0 comments: