Numerical Optimization of Spray-Guided Spark Assistance for Cold Idle Operation in a Heavy-Duty Gasoline Compression Ignition Engine

This article describes the results of a response surface model (RSM)-based numerical optimization campaign for spray-guided spark assistance at cold operations in heavy-duty gasoline compression ignition (GCI) engine. On basis an earlier work on spark-assisted GCI combustion, space-filling design experiments (DoE) method was first undertaken to investigate multitude hardware variables and engine operating parameters. The main included number injector nozzles, fuel split quantities injection timings, timing. objective were combustion efficiency (ŋc), maximum pressure rise rate (MPRR), engine-out nitrogen oxide (NOx) emissions. A total 150 candidates automatically generated using Sobol sequence provided by commercial software package, CAESES. Then, closed-cycle computational fluid dynamic (CFD) simulations under idling performed. outcomes from CFD-DoE utilized construct high-fidelity RSMs that allowed further plug- injector-related variables, along with strategy merit function respect formulated appropriate weight assignment each variable. Finally, best candidate identified RSM-based process validated CFD analysis. showed potential significantly improve (ŋc > 90%) over baseline idle while satisfying MPRR NOx emissions constraints (MPRR < 5 bar/CAD 4.5 g/kWh).