A Study Of The Effect Of Port-injected Methanol On Diesel Engines Operating With F-T Diesel

With the increasing environmental pollution, human turns more sight to how to protect our survival environment. Engine promotes social progress, also becomes the instigator of the destruction of the environment. F-T diesel can reduce emissions of diesel engines, but its cost is relatively high. Based on the characteristics of F-T diesel fuel as base fuel and ensuring engine power, this paper studies reducing economic indicators and the emissions further and recearches the combustion characteristics cyclic variation characteristics, noise and vibration characteristics and simulation analysis of the4100QBZL turbocharged intercooled diesel engine using an intake port methanol injection system through combination of simulation and test methods. This provides basis research for the application of alternative fuels.The three different energy replacement rates of methanol (5%,10%and15%) injected into the inlet are achieved by spraying methanol electric control unit.15%methanol replacement rate has the best economy and maximum utilization at low speed and5%methanol replacement rate saves fuels at maximize extent at middle and high speed. FT diesel can reduce NOx emissions and this paper studies FT diesel combustion gas mixture containing methanol. The results show that:With the increase of the ratio of methanol alternative, NOx emissions reduce than FT diesel emissions. Because the test process does not have the exhaust gas after-treatment device, HC and CO emissions significant increase and soot emissions change in a low magnitude at different operating conditions.The combustion process of various fuels can evaluate and determine the various effects on the output characteristics of the engine. This paper studies the combustion process of F-T diesel and three different ratios of methanol using F-T diesel as a base oil and the results show that:as the increase of the rate of methanol, the maximum combustion pressure, the maximum pressure rise rate, the maximum instantaneous heat release rate and in-cylinder temperature increase and crank angle value of start combustion is gradually close to the top dead point so that the combustion is delayed.To further study effect of the replacement rate of methanol on diesel engine combustion process, this paper studies the cycle-by-cycle variations of the maximum oil pressure of the high-pressure tubing, maximum cylinder pressure, peak of pressure rise rate, crank angle value of start combustion and the maximum combustion temperature. With the increase of the methanol replacement rate, the cycle-by-cycle variation coefficient of the highest fuel pressure increases, the cycle-by-cycle variation coefficients of other parameters are not high, but higher than F-T diesel. The impact of different ratio of methanol on the combustion process is different.The effect of the different replacement rate of methanol on combustion process is also reflected in the diesel engine noise and vibration. Acceleration sensors are installed on the cylinder block, cylinder head and a high pressure pump to measure the vibration signal and sound pressure sensor measuring the engine noise signal is installed just above the engine. With the increase of the replacement rate of methanol, the effect on the vibration of cylinder block, cylinder head and pump changes as changes of the speeds and loads, but engine noise increases.The results of simulation analysis using FIRE software show that the fuel concentration and temperature of the cylinder can be reduced by using methanol and help to reduce NOx emissions.