The United States' increasingly stringent fuel economy standards require the development of new more fuel efficient combustion technologies as large gains with conventional spark ignition combustion decline. Turbulent jet ignition enables a near 20% peak thermal efficiency improvement relative to spark ignition combustion, resulting in both lower fuel consumption and CO2 emissions. This research aims to examine fundamental aspects of the turbulent jet ignition (TJI) process, which utilizes pre-chamber combustion initiation. The TJI concept involves the use of a chemically active, turbulent jet to initiate combustion in lean or dilute mixtures. The large number of distributed ignition sites provided by the turbulent jet enable short combustion durations even in the traditionally slow burning mixtures that occur with low temperature combustion (LTC). The objectives of the proposed research are 1) to experimentally examining the active radicals generated in the TJI process through both rapid compression machine and optically accessible engine experiments, 2) to develop a new LES modeling technique to model the TJI system, as both turbulence and active species from the pre-chamber play a role in TJI combustion and 3) to experimentally examine the controllable cavity TJI system?s performance and efficiency in metal engine tests.
