Hydraulic Electronic Unit Injector with Rate Shaping Capability

Caterpillar^® Fuel Systems has developed a next generation hydraulically actuated electronically controlled unit injector with a direct operated nozzle for providing independent control of injection pressure and rate shape as well as multiple injections per cycle. These advanced features are considered important building blocks for future DI diesel engine emission regulations and performance improvements. Initial injector performance testing of the concept hardware identified several areas of concern, prompting root cause analysis and redesign work to derive solutions. The resulting improvements have been incorporated into the production injector design, and subsequent bench and engine tests have demonstrated the capabilities of this advanced fuel system. This paper documents the design, testing and analysis that led to the development of the new Caterpillar HEUI™ B fuel system for diesel engines.