Performance Comparison of Unit Injector and Pump-Line-Nozzle Injection Systems

The performance of a diesel engine normally improves by raising fuel injection pressure and shortening the injection duration. This paper compares the potential of meeting this design goal with two different types of injection systems-unit injectors and pump-line-nozzle systems. The comparison is based on simplified models that describe the generic hydraulic performance of each type of injection system and the design trade-offs that influence injection system performance. The sensitivity of design variables are compared versus injection pressure and injection duration.