| Bosch is working on common rail
diesel systems without the rail. Removing the fuel rail and leaving only
the fuel lines could cut cost and make other design solutions possible.
Bosch diesel systems engineering chief Dr Rolf Leonhard said: “It’s
an evolution of common rail, not a completely different injection system.”
Common rail direct injection has come to dominate the passenger car diesel
engine market in the ten years since Bosch introduced it. It delivers
improved refinement, economy and cleanliness but at a relatively high
cost, especially with maximum injection pressures of up to 2000bar.
Leonhard said: “We need a volume of high-pressure fuel between the
injectors and the pump. But you could take the volume – at the moment
in the rail – and put it in the injectors.”
Other systems have challenged common rail in the past but are now being
phased out. Bosch supplies VW with unit injector pumps but Leonhard said
these will disappear around 2010. VW’s latest TDI engines have switched
to common rail.
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