What Car? Q&A - What does PD stand for on VWs?

Q: I know that the initials PD, found after GTI on the rear of some VW Golfs stands for Pumpe Duse, but what does it mean?
Chris Mort via e-mail

A: The term translates from German directly as 'unit injector', and refers to the method of fuel delivery used by all modern Volkswagen diesel engines. Conventional diesels have one fuel pump, but this system has four.

This means that the fuel can be more highly pressurised, and used more efficiently by the engine.

Volkswagen says the benefits of Pumpe Duse include a high power output, coupled with low emissions and excellent fuel efficiency.