Visualization of Passive Pre-chamber Jet Ignition in a Modified Gasoline Engine
2022-01-0529
03/29/2022
- Event
- Content
- Pre-chamber turbulent jet ignition (TJI), an advanced ignition technology, has been considered for gasoline engines as a replacement for the traditional spark ignition. TJI has the potential to enable lean or EGR operations of engines and reduce cyclic variation. The hot turbulent jet is generated by burning a fuel/air mixture in a separate small volume called the pre-chamber. The higher pressure resulting from pre-chamber combustion pushes the combustion products into the main chamber in the form of a hot turbulent jet, which then ignites the lean mixture in the main chamber. Compared to a conventional spark plug, the hot jet has a much larger surface area leading to multiple ignition sites on its surface which can enhance the probability of successful ignition and cause faster heat release and flame propagation. The objectives of this paper are to examine the pre-chamber jet ignition process with a high-speed visualization and to understand the pre-chamber performance for a range of geometric and operational parameters. The apparatus adopted a modified GM 4-cylinder 2.0L gasoline engine in which a single-cylinder custom block with an optically accessible piston was installed to allow optical access and instrumentation. To focus on the ignition and combustion processes in pre-and main chambers, the piston position was fixed at a pre-defined position relative to the top dead center. The upstream flow was conditioned to simulate engine relevant conditions (temperature up to 900K and pressure up to 30bar). High-speed imaging was applied to visualize the jet penetration and ignition process inside the main chamber. A total of three different pre-chamber geometries were examined in this study, all of which are different in size of nozzles and geometry. In addition, operating conditions were varied representing different EGR dilutions to examine their effect on a passive pre-chamber performance.
- Citation
- Lee, D., Yu, T., and Qiao, L., "Visualization of Passive Pre-chamber Jet Ignition in a Modified Gasoline Engine," SAE Technical Paper 2022-01-0529, 2022, .