Combustion Sensing in Pre-Combustion Chambers Using Ion Sense
Further reduction in NOx emissions can only be obtained by improving engine combustion control at the cylinder level. This requires cylinder level sensors capable of continuously monitoring combustion performance in both the main chamber and the pre-combustion chamber (PCC). Until recently, in-PCC combustion measurements were only possible in the laboratory using very expensive pressure sensors with extremely short lives. Ion Sense now offers a more robust and cost effective method to monitor in-PCC combustion. Derived from automotive technology, Ion Sense utilizes post ignition ionization measurements from a standard spark plug. When measured from a spark plug mounted in a pre-combustion chamber, Ion Sense provides a wealth of previously unavailable information on flame initiation, early flame propagation, in PCC air/fuel ratio, etc. As part of the Pipeline Research Council Internationals (PRCI) Emission Reduction for Legacy Engines (ERLE) Task 1e project, a Hoerbiger lead research team investigated the use of Ion Sense data collected in the PCC to monitor and control in PCC air/fuel ratio, main chamber air/fuel ratio control and the optimal control of combustion timing in both. This paper will report on the results of this testing and review the potential feasibility and benefits of applying Ion Sense based monitoring and control of PCCs for pipeline engines both for research on continuous performance monitoring.