Piston Bowl Geometry Effects on Combustion Development in a High-Speed Light-Duty Diesel Engine
In this work, we studied the effects of piston bowl design on combustion in a light-duty direct-injection diesel engine. Two bowl designs were compared: a conventional, omega-shaped bowl and a stepped-lip piston bowl. Experiments were carried out in the SNL single-cylinder optical engine facility, with a medium-load, mild-boosted operating condition featuring a pilot+main injection strategy. CFD simulations carried out with the FRESCO platform featuring full-geometric modeling of the engine, were validated against measured in-cylinder performance as well as soot natural luminosity images. Differences in combustion development were studied using the simulation results, and sensitivities to in-cylinder flow field (swirl ratio) and injection rate parameters were also analyzed.