A new Piezo Common Rail Injector with direct Drive and Closed Loop Functionality: Concept and Engine Benefit

摘要

In the conflict of further reduction of emissions and fuel consumption as well as the cost of production, the optimum balancing of measures to reduce emissions engine out or at the tailpipe plays a vital role. Compared to the current optimized, more robust design of intake and combustion system for EU6, the fuel injection system has a large influence on sample-to-sample deviation of exhaust and noise emissions due to its mixture formation characteristics but also its production tolerances. Within the injection system, the injector concept disproportionately determines engine performance and emissions as well as injection system cost. The concept of the new 2000 bar piezo common rail injector with direct drive is providing a closed loop injector control for the first time. This constitutes an "emissions reduction module", which provides multiple features for reproducible rate shaping as an alternative to the commonly known multiple injection patterns. Via the detection of nozzle needle position during injection, the control loop for the fuel mass can be closed for the first time. The drift and sample-to-sample deviations which remain in spite of the robust hydraulic design will be recognized and compensated for safely. In this presentation the chosen direct drive concept as well as the fuel mass control loop will be introduced. The hydraulic performance will be discussed as well as the first results from single and multi cylinder engines. These will confirm the significantly extended potential of this injector concept to fulfill future requirements in comparison to current solutions.