Jetfire Ignition: A New Era for High-Speed, High-Efficiency, Stoichiometric Engines

Authors

H. Schock, MSU Michigan State University

Summary

Since its introduction decades ago by L. A. Gussak and his colleagues, Turbulent Jet Ignition (TJI) systems have been known to provide very high-efficiency lean engine operation. Advances in electronic actuators, including fuel injectors, electronic computer controls, and the knowledge from decades of combustion research have rekindled global interest in these systems. This presentation describes a system which actively controls the fuel and air admitted to the pre-chamber, independent of the main chamber. This permits the combustion system to accommodate high-EGR stoichiometric operation. The technology is termed a Jetfire system, disclosed in six US and international patents or pending patents. The Jetfire system is in its fourth generation, with a distinguishing feature being a mechanical system managing pre-chamber air enabled by concentric camshafts and electric phasers. The ConCam technology of ThyssenKrupp dynamic components provides a highly efficient method of controlling air admission to the pre-chamber. The system is currently operational in a single-cylinder configuration. Initial estimates indicate that compression ignition efficiencies can be achieved with this system, using low-carbon fuels, operating at highly dilute (EGR) stoichiometric conditions, thus enabling the use of a three-way catalyst for emission control.