For various engine loads, the authors determine the optimal operating factors for low BSFC (brake specific fuel consumption), NOX, and smoke.
A cost function was also designed in this study, considering the factors of coal consumption, NOX emissions and the recycling potential of fly ash.
The conversion relationship between the nitrogenous species (including NO, NO2, HCN, etc)., NOx formation and consumption pathways, and NOx and CO emission indices of the DME/air jet diffusion flame were analyzed by reaction rate and sensitivity analyses.
Numerical models of a low-speed two-stroke diesel engine, turbochargers and an ORC (organic Rankine cycle), are used for the optimisation of the NOx and fuel consumption at design and part-load conditions, using a multi-objective genetic algorithm.
Compared to the prototype gasoline-fueled engine, the average decreases of the equivalent specific fuel consumption, NOx emissions, CO emission and total hydrocarbon emissions for the optimized engine fueled with hydrogen-rich reformates are 6%, 70 %, 50 % and 80 respectively.
The results indicated that the brake thermal efficiency, particulate matter, unburned hydrocarbons, carbon monoxide emissions reduced with increased concentration of biodiesel in the fuel blends, whereas the specific fuel consumption, NOx emissions and exhaust gas temperature increased.
The various mechanisms of NOx production and consumption are verified to be strongly dependent on the flame temperature and on superequilibrium concentrations of radicals, both fuel-derived and from hydrogen oxygen chemistry; the flame-structure analysis was extended to provide sufficient accuracy in the prediction of these quantities.
In the present study the specific energy consumption, NOx emission and the exhaust gas temperature increased by 6%, 8% and 14%, respectively, and brake thermal efficiency and smoke level reduced by 5% and 8%, respectively, using carburation technique compared to baseline diesel.
