Delphi has developed a 1mm valve allows up to nine injection events for heavy-duty diesel applications. The valve for the DFI 21 injector forms part of the Tier One’s F3 family of common rail systems.
When combined with improvements in hydraulic efficiency and the consistently precise control provided by the new closed-loop system, the DFI 21 injector allows up to nine injection events per cycle compared with just two-three for a typical Euro VI system.
Delphi’s vice-president of powertrain and general manager for fuel injection systems Kerem Erman said: “The ability to effectively profile the combustion means that the need to compromise between CO2, NOx and particulates is greatly reduced. That gives engine designers much greater flexibility in their aftertreatment strategy, potentially reducing system costs and allowing a reduction in SCR fluid consumption, which can be of significant value to long distance operators.”
The ability to specify precise, multiple injection strategies should allow engineers to substantially improve opportunities to profile the entire combustion event. Peak temperatures could be minimised, reducing NOx creation, and post injections can be specified to reduce soot.
The technology has been tested by Delphi and engine manufacturers, and according to the firm has shown good injection stability, with consistent clean start and finish to each event. By allowing combustion to begin more gently, multiple pilot events also provide a significant improvement in engine refinement.
Delphi anticipates improvements in fuel economy of up to 1.5% from the combustion improvements. Further reductions in emissions and fuel consumption will come from hydraulic efficiency improvements in the fuel system.
Delphi currently anticipates the first applications for the new F3 commonrail system will enter production around 2021.