High-pressure common rail systems for heavy-duty diesel engines meet Euro VI standard

May 02, 2012 // By Christoph Hammerschmidt
Automotive tier one Delphi claims it has achieved a breakthrough in common rail fuel system technology for heavy-duty diesel engines. The systems, which have been introduced at the 33rd Vienna Motor Symposium (April 26-27) combine proven hardware with an innovative architecture, allowing vehicle manufacturers to meet tough Euro VI emissions standards without significant modification to their base engines.

At the same event, Delphi also revealed its new common rail system for small, one to four cylinder diesel engines, including non-automotive applications. This concept system aims at heavily downsized applications and developing markets.

A combination of highly efficient injector design, configurable pump layout and sophisticated air and fuel control strategies has provided a highly-flexible, modular solution for large engines between 7 and 16 litres displacement.

Delphi's new heavy-duty common rail system will be available in three configurations: two Distributed Pump Common Rail Systems (DPCRS), in which the pressure is provided by a number of separate pumping units, and a Remote Pump Common Rail System (RPCRS), which is similar to traditional common rail layouts. Running initially at 2700bar injection pressure, the technology is capable of operating at up to 3000bar to meet the requirements of future legislation, beyond Euro VI, that might limit the permissible CO2 emissions from heavy commercial vehicles. Delphi has been working on the Euro VI systems since 2005.

“For Delphi, Euro VI represents evolution, not revolution," said David Draper, engineering director, Delphi Heavy-Duty Diesel Systems. “We have substantial experience with very high pressures and already manufacture some of the most sophisticated control valves available. Combining this with innovative new architectures and control systems has allowed us to significantly reduce the cost of Euro VI compliance for our customers while continuing to improve fuel economy and CO2 emissions.”

According to Delphi, DPCRS technology is ideal for engines currently using Electronic Unit Injector (EUI) systems or Electronic Unit Pump (EUP) systems because the installation envelope is the same as that for current products. The ultra-high rail pressure is provided by a flexible number of separate pumping elements that can operate from either cam-in-block (F2P system) or cam-in-head (F2E system) engines. The overhead cam arrangement allows all high-pressure elements of the system to be contained within the rocker cover and neither system requires significant change to the castings of an engine