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This paper reviews progress on turbulent jet ignition systems for otherwise standard spark ignition engines, with focus on small prechamber systems (≺3% of clearance volume) with auxiliary pre-chamber fueling. The review covers a range of systems including early designs such as those by Gussak and Oppenheim and more recent designs proposed by General Motors Corporation, FEV, Bosch and MAHLE Powertrain. A major advantage of jet ignition systems is that they enable very fast burn rates due to the ignition system producing multiple, distributed ignition sites, which consume the main charge rapidly and with minimal combustion variability. The locally distributed ignition sites allow for increased levels of dilution (lean burn/EGR) when compared to conventional spark ignition combustion. Dilution levels are comparable to those reported in recent homogeneous charge compression ignition (HCCI) systems.

The flow inside of an internal combustion engine is highly complex and varies greatly among different engine types. For a long time IC engine researchers have tried to classify the major mean flow patterns and turbulence characteristics using different measurement techniques. During the last three decades tumble and swirl numbers have gained increasing popularity in mean flow quantification while turbulent kinetic energy has been used for the measurement of turbulence in the cylinder. In this paper, simultaneous 3-D LDV measurements of the in-cylinder flows of the three different engines are summarized for the quantification of the flow characteristics. The ensemble averaged velocity, tumble and swirl motions, and turbulence kinetic energy during the intake and compression strokes were examined from the measured velocity data (approximately 2,000 points for each case) by the 3-D LDV system.