| The study of alternative energy sources had already been developed all over the world because of energy sources problem. Ethanol as one of the most potential alternative fuels has became the study emphasis.The physical and chemical characteristics of ethanol are different from that of diesel. The mutual dissolubility of ethanol and diesel is very poor so as to bring delamination and the steady emulsion isn't produced. A solublizer was added to the blend of diesel and ethanol to improve their mutual dissolubility and to prepare diesohol fuel. The diesohol didn't bring delamination above freezing point temperature and the stabilization time exceeded three month.The main physical and chemical characteristics of diesohol were simply calculated using experience formula. The density, the cetane number, the low heat value and the flash point of diesohol are lower than diesel, but the vaporization heat is higher. The rule changes evidently when the volume concentration of ethanol is increased. These will affect the performance of engine fueled with diesohol.Without any configuration modification of a turbocharged intercooled CI engine, and keeping same volume supply delivery of different fuels at the same mode, extensive experiments were carried out on a engine fueled with diesel and three kinds of diesohol fuels (E10, E15 and E20).The results of engine full-load characteristic show that the power output of engine decreases as the ethanol volume concentration of diesohol fuel increases. The results of engine constant speed characteristic show that the brake specific fuel consumption (bsfc) increases, especially at the low load while the brake specific energy consumption (bsec) using diesohol increases at the low load and is equivalent at the moderate and high load range in comparison with that of the diesel fuel. The smoke emission decrease obviously, CO concentration emission increases at the low load of the low speed conditions while is equivalent at the moderate and high load, HC concentration emission increases gradually, especially at the low load, and NOx concentration emission decreases at the low and high load while increases at the middle load.The results of exhaust emission characteristics according to ECE R49 13-mode show that the brake specific emissions of CO, HC, NOx, PM and SOF fueled with disohol are higher than those of the diesel fuel operation, while brake specific emissions of DS are lower as the ethanol volume concentration of diesohol fuel increases. The rule of brake specific emission and concentration emission is different owing to decreasing of power output.The results of combustion characteristics show that the pressure in the cylinder gradually decreases as the ethanol volume concentration of diesohol fuel increases while the ratio of pressure rise gradually increases and the working process becomes rude. The periods of ignition delay prolong in collectivity trend, and the combustion duration is shortened. The maximum value of heat release gradually decreases at the low load, but it increases at the moderate and high load.The experiment results were analyzed, the low heat value, high vaporization heat and low cetane number of ethanol badly affect the performance of the turbocharged intercooled CI engine fueled with diesohol and they are the main reason of the performance decreasing. Without any adjustment for a turbocharged intercooler CI engine fueled with diesohol, the ethanol volume concentration of diesohol doesn't exceed 10%. Fueled with E10 diesohol, the brake power of engine decreases 5.9% and the maximum torque decreases 5.2% while the specific fuel consumption and HC emission increase, especially at the low load. Smoke decreases evidently and other emissions change few.According to the trend and rule of above experiment results, the experiments were carried out on a engine fueled with E10 diesohol to improve engine performance by increasing the inlet temperature, adjustment fuel supply advance angle, using ignition improver and decreasing ethanol vo... |
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