PR-336-06206-R01 Engine Control for Legacy Engines – Cylinder and Cycle Level Control

The reduction or even elimination of cylinder to cylinder combustion variation and cycle-to-cycle combustion instability may result in further nitrous oxides (NOx) reductions at the same engine average air/fuel ratio (and hence turbocharger operating point) or allow operation at a leaner air/fuel ratio before the onset of instability. Reductions in imbalance and instability can also reduce carbon pollutant emissions, reduce break specific fuel consumption (BSFC) and improve engine operability. Achieving these goals requires a better understanding of the sources and impacts of that imbalance and instability and then the development techniques to reduce if not eliminate both.

This effort focuses on combustion instability of legacy large bore pipeline reciprocating engines operating at very high air/fuel ratios to meet higher emission standards. The report provides a detailed cycle-to-cycle analysis of acquired pressure and ion current data of four test engines in-cluding Clark T-series family and Cooper Bessemer GMV/W engines. The possibility of upcom-ing misfire or poor combustion prediction is investigated and discussed. The document further investigates advanced cylinder balancing strategies as well as the benefits of improved pre-combustion chamber performance.