Pump Duse Vs CRDi

Pump Duse technology or Common Rail Direct Fuel Injection which one's better? This debate has been going on for a while now.

Pump Duse technology or Common Rail Direct Fuel Injection which one's better? This debate has been going on for a while now. However, is there an answer to which technology emerges supreme? Simply put, while cars such as Ford Fiesta, Tata Dicor and Hyundai Verna use CRDi technology other cars such as Skoda and Volks Wagen Passat use Pump Duse technology.

In Pump Duse technology, the Crankshaft of the engine drives a pump camshaft with the same number of cams as the number of pistons. This is mounted to one side of the engine as opposed to the top, especially in OHC engines. Each of the cam drives a Unit injector which works on the principle of Hydraulics, using a small mechanical pump to pressurize fuel to very high levels.

The Unit injector is basically a piston driven by the cam below in a small cyinder. There is no fuel inlet port that opens as the piston slides down, delivering fuel under pressure into the cylinder, from an electric pump. As the cam turns, the port closes and the fuel is pressurized further, ready to be released by the electronic actuator that opens and closes by command of the ECM. The actuator thus is able to deliver fuel from the Unit Injector into the combustion chamber at very high injection pressures of 1600-1800 bar, in various injection modes and programs.

The entire unit of injectors is usually miniaturized and built into a single piece instrument when installed in car engines.

While the Pump Duse offers more torque and less pollution, the Common Rail injection on the other hand is believed to build quieter and smoother engines. Also, in terms of excessive mechanical and combustion noise levels there has been a great amount of reduction and this is also seen vis-a-vis vibration.

Common Rail Direct Fuel Injection which is known to have revolutionized diesel engine technology is a modern variant of Direct Injection system for diesel engines. It boasts high pressure fuel rail feeding individual solenoid valves as opposed to low pressure fuel pump feeding pump nozzles or high pressure fuel line to mechanical valves controlled by cams on the camshaft. Third generation common rail diesels now feature piezoelectric injectors for even greater accuracy.

While Pump Duse beats CRDi in terms of power and torque, CRDi is more cost effective, is less noisier and a shade better in terms of emissions.