Optimization of homogeneous charge compression ignition with genetic algorithms

Abstract

Homogeneous charge compression ignition (HCCI) engines promise high efficiency and low emissions, and thus these engines hold great potential for reducing pollution in electric power generation, trucks, marine vehicles, locomotives, and automobiles. Controlling the time of the HCCI combustion event remains a major technical difficulty yet to be overcome. An integration of genetic algorithms (GAs) with well-mixed reactor simulations is developed for better understanding HCCI combustion and for guiding the development of optimal controls. With GAs, the effects of engine intake charge on engine performance are explored with three fuels: methane, propane, and acetylene. Simulation results are compared to available experimental data showing that model predictions are consistent with known trends. As the first application, GAs are used for searching the optimal intake charge conditions of HCCI combustion for power generation with methane. Results suggest that the use of intake charges with high equivalence ratio and with large amounts of exhaust gas recirculation is optimal. Subsequently, parameter optimization for intake conditions with the stoichiometric mixture at various power demand is explored. The results are analyzed and insights on the optimal managing schemes are revealed.

Combustion and Emission Characteristics of Partial Homogeneous Charge Compression Ignition Engine

“…Also, Chen et al (2003) and Tanaka et al (2003) showed that the ignition delay decreases with increasing equivalence ratio and intake temperature. This trend is applied to the partial HCCI combustion in this study, too.…”

“…HCCI engines can have efficiencies as high as that of a direct-injection (DI) diesel engine, while producing extremely low oxides of nitrogen (NO x ) and particulate matter emissions (Chen et al, 2003;Christensen and Johansson, 1998;Tanaka et al, 2003). On the other hand, many investigators demonstrated that HCCI engines have a fairly high level of hydrocarbon (HC) and carbon monoxide (CO) emissions due to their low combustion temperature, although these incomplete products combustion can be removed with oxidation catalysts.…”

“…Also, the gasoline and diesel fuels were used as the premixed fuel to analyze the effect of each premixed fuel on the combustion. Intake temperature is one of the most influential factors on ignition timing and combustion duration of HCCI (Chen et al, 2003;Tanaka et al, 2003); it is now generally agreed that HCCI combustion is dominated by local chemical kinetic reaction rates and these reaction rates are most sensitive to temperature. Therefore, the effects of inlet charge temperature on partial HCCI combustion are investigated under various conditions.…”

HCCI experiments with gasoline surrogate fuels modeled by a semidetailed chemical kinetic model

“…by various investigators and modeling on the HCCI process using a detailed chemical kinetic mechanism has also been included in these studies [6][7][8][9][10][11][12][13].…”

Modeling of emissions from HCCI engines using a consistent 3-zone model with applications to validation of reduced chemistry

“…This single-zone model assumes that the composition and temperature inside the combustion chamber are completely homogeneous. Such a simplified model has been useful in providing a rapid estimate for SOC as a function of intake charge properties [8,9]. It is well known that the piston crevice stores unburned charge during the compression stroke and later, during the expansion stroke, discharges these unburned gases back into the main cylinder [7,10].…”