| Rapidly development of Globle’s automobile industry, brings growing dependence on oil resources and the environment pollution problem. Looking for clean and renewable alternative fuel has great significance, among them, methanol is a promising alternative fuel. By cracking methanol into dissociated methanol gas, and bring it into cylinder in order to combust, not only can reduce fuel consumption, but rich hydrogen composition fuel can effectively improve cylinder combustion process, increase engine’s thermal efficiency and reduce emission.By choosing high-precision sensor and using Lab VIEW software, this paper developed a cylinder pressure test system used for combustion analysis, including gasoline engine and mixed methanol dissociated gas engine. Hardware part expounded the principle of key hardware selection methods, including crank angle sensor, cylinder pressure sensor, charge amplifier and data acquisition equipment, hardware anti-interference measures in the experiment. Software part expounded the data acquisition scheme and the engine combustion heat release analysis methods. By using mixed programming of Lab VIEW and MATLAB to write programs which can be used in gasoline and mixed methanol dissociated gas engine, including TDC calibration, cylinder pressure data acquisition and combustion heat release analysis program.The engine test results show that after combust mixed methanol dissociated gas, the engine’s maximum combustion pressure, maximum pressure rise rate were improved, the highest pressure corresponding crank angle was slightly advanced. The heat release rate peak was higher, its corresponding location was advanced. Effective thermal efficiency was higher, the CA50 location was advanced. The performance was more obvious with the increasing of replacement ratio and under small and medium loads. In lean-burn conditions, with increasing excess air ratio( ? ?1.1),mixed methanol dissociated gas engine’s combustion process can be obviously improved. |
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