A new Electronic Unit Injector (EUI) has been developed by Delphi Automotive Systems for use in large diesel engines. The compact injector can directly replace previous generation injectors, providing much greater flexibility in cylinder head packaging. It also improves peak injection pressure and injector responsiveness, and is half the weight of previous designs, saving 6.6kg on a six-cylinder engine.
‘It is a highly attractive technology for diesel engines from 9.0 litres up to 16 litres,’ said Guy C. Hachey, President, Delphi Energy & Chassis Systems.
EUI systems use a separate pump for each injector, traditionally integrating the pump with the injector body and mounting the spill valve and control solenoid on the side of the body. This provides a highly effective unit with excellent responsiveness, but the offset forging required makes it both bulky and complicated to manufacture.
Delphi has overcome these issues by developing new technologies that allow the spill valve and control solenoid to be integrated within the injector body, concentric with the pump and nozzle mechanisms. This provides a very compact unit which, compared with the previous generation EUI, is no larger than the conventional injector body alone and uses 40 percent fewer components.
The shorter, more direct fuel path allows more accurate fuel metering, improved injector responsiveness and a peak injection pressure of 2000 bar, up 15 percent compared with the previous generation unit with no increase in power consumption.
Elimination of the offset forging considerably increases opportunities for improved cylinder head and valvetrain layouts and reduces the weight of each unit from 2.2kg to 1.1kg – resulting in a considerable saving on six and eight cylinder engines. The unit is designed to be maintenance free for 1 million km, providing further savings for vehicle operators.
The E1 was designed at Delphi’s Park Royal Technical Centre in London, where Euro IV and Euro V versions are currently under development. To achieve the fine tolerances necessary for the E1 (many smaller than one micron), Delphi has installed a new manufacturing line at its specialist heavy-duty plant in Stonehouse in the UK, where production of the E1 has already started for a European heavy-duty application. An electronic unit pump with a separate injector is available for cam-in-block applications.