APPLICATION OF AN ADVANCED IN-LINE INJECTION SYSTEM TO A HEAVY DUTY DIESEL ENGINE

Future emission standards for heavy duty diesel engines will require the application of improved fuel injection systems with high pressure capability and electronic control of timing and fuelling. A recent Ricardo research project has concentrated on the application of the latest in-line pump from Robert Bosch, designated RP39, to a prototype turbocharged and aftercooled heavy duty diesel engine based on the Volvo TD122. The maximum pressure capability of the prototype RP39 used during the experiment was 1400-1500 bar at the injector nozzle. The pump also featured electronic control of the injection timing and rate by the sleeve control principle. The RP39 was matched to a revised low swirl combustion system. Results from steady state and transient tests are presented highlighting NOx/fuel economy/particulate trade-offs and their response to injection pressure, rate and timing, leading to a demonstration of how 1991 engineering targets for NOx and particulate were readily achieved and the 1994 legislative standard approached with limited development. The potential for further improvement is discussed.