<p>Recent research has demonstrated that gasoline compression ignition (GCI) can improve the soot-NOx tradeoff of conventional diesel engines due to the beneficial properties of light distillate fuels.&nbsp; In addition to air and aftertreatment systems, fuel systems also require development to realize the potential fuel economy and emissions benefits offered by GCI.&nbsp; 1-D hydraulic modeling is an important fuel system design tool used for this purpose.&nbsp; The current study is a continuation of prior work that presented a novel methodology for generating physical property databases of real light distillates and their use in a hydraulic model to accurately capture high-pressure injection behavior relevant to GCI.&nbsp; Calibration of an established diesel injector model for operation with gasoline-like fuel was automated by employing multi-objective Pareto, multi-objective weighted sum, and transient targeting optimization approaches coupled to a genetic search algorithm.&nbsp; With the right selection of optimization targets and calibration parameter ranges, all these techniques were effective at determining the adjustable model discharge coefficients needed to best represent experimental data.&nbsp; However, multi-objective Pareto offered the greatest overall improvement on rate of injection and total injected quantity closure compared to the manual calibration procedure used previously.&nbsp; The validated gasoline injector model was then used to determine the optimal hardware configuration needed to approach an idealized, slowly opening rate shape that could enable low-NOx GCI combustion.&nbsp; Initial parametric studies of key injector hardware parameters affecting rate shape showed that changing a combination of nozzle exit orifice diameter, servo (or control) chamber outlet orifice diameter, and needle orifice diameter could achieve the desired single injection fueling profile.&nbsp; A transient targeting optimization technique coupled to a genetic search algorithm was compared to a full factorial design of experiments for meeting the rate shape target and highlighted that the former approach was superior in terms of matching and computational runtime.&nbsp; In general, this study provides a robust methodology for accurately simulating gasoline-like fuels in high-pressure injectors and demonstrates a conceptual rate shape targeting process for GCI combustion concepts using 1-D hydraulic models.&nbsp; This tool could potentially be integrated with predictive 3-D computational fluid dynamics models to achieve a simulation-led combustion system design process that includes rate shaping as an additional avenue for optimization.</p>

Injection Rate Shape Design of Gasoline-Like Fuels Using 1-D Hydraulic Models Operating at High Pressures

Paper Proceedings: https://asmedigitalcollection.asme.org/ICEF/ICEF2021/volume/85512

ASME 2021 Internal Combustion Engine Division Fall Technical Conference (ICEF2021)

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