Citroën Xantia HDi 

With the introduction of the new HDi Common Rail direct injection diesel engine, the Xantia becomes the first car in the UK to benefit from PSA's research programme. 

The Next Generation Common Rail technology is inherently simple - a pump pressurises the DERV to 1350 bar - twice the pressure of a conventional diesel engine - and hold the fuel at this high pressure in a reservoir known as a Common Rail which feeds the fuel into computer controlled injectors.

The injectors act as taps that can open and close in microseconds allowing the system to precisely meter the quantity, timing and pressure of fuel injection to a degree of accuracy that was never previously possible.

This accurate control also enables the pilot injection of a miniscule amount of fuel a few milliseconds before the main injection which then produces a complete and progressive burn. This softening of the ignition reduces noise by 3 dB.

The benefits are improved economy, seamless acceleration, quieter running and greater refinement.