Analysis and Application of Advanced Balancing Techniques for PCC Fitted Pipeline Engines
Further reduction in NOx emissions can only be obtained by improving engine combustion control at the cylinder level. As part of the ERLE (Emission Reduction for Legacy Engines) task 1c (Cylinder and Cycle Level Control) initiated by the Pipeline Research Council International (PRCI) the combustion performance on different pipeline engines at several air/fuel ratios, speed and loads have been investigated. The evaluation of continuously monitored in-cylinder pressures shows a significant correlation between air/fuel ratio based cylinder balance and combustion stability. Furthermore, the effects of in-PCC air/fuel ratio balance as well as ignition timing have been examined both qualitatively and quantitatively. Based on these findings, cylinder and prechamber balancing techniques were developed which ensured improved operating stability closer to the lean air/fuel ratio limit. The paper will present these advanced balancing methods based on peak pressure, IMEP, heat release, mass fraction burned and corrected trapped equivalence ratio. It will describe the fundamentals behind these methods based on theory and measured data. In addition, the demonstration on a Clark TLA6 engine will be presented. The results will be summarized in a benefit assessment regarding emission reduction, fuel efficiency and operating stability.