Design and teaching application of an experimental platform for combustion analysis of low-carbon alcohol gasoline engines
[Objective]New technologies and techniques have significantly affected the development of internal combustion engines,leading to continuous improvements in their performance indexes.Among these innovations,data acquisition and combustion analysis technologies have played an immeasurable role in promoting internal combustion engines.This paper aims to study the specific combustion state of low-carbon alcohol blended gasoline within the cylinder,as simulations alone do not fully capture the combustion process.The research focuses on enhancing the combustion analysis function of a traditional naturally aspirated injection gasoline engine.[Methods]To obtain experimental data such as pressure,exothermic rate,and combustion mass fraction,the combustion pressure in cylinder 1 of the gasoline engine was measured using a sophisticated pressure collection device.The crankshaft angle position was also encoded and processed.The collected pressure data underwent low-pass filtering and averaging.The exothermic characteristics of the combustion process in the cylinder of the internal combustion engine were analyzed using the instantaneous combustion pressure curves from several engine operating cycles collected,applying the first law of thermodynamics.This analysis served as a criterion for evaluating the combustion state of different fuels under various operating conditions and overall engine performance.Prior to starting the gasoline engine experiments,several safety checks were conducted.These included verifying the engine coolant and oil levels,inspecting for leaks in the high-pressure oil pipe,oil consumption meter inlet and outlet oil pipes,and the oil cap,and ensuring the pipeline connection is firm.It was also necessary to check whether the normal operation of the engine starter and the battery's electrical connections.After confirming there were no abnormal states,the dynamometer cooling water was turned on,excitation was added,and the throttle opening and startup load at startup were set to 0.The engine was then started and warmed up for at least 15 min,maintaining the engine cooling water temperature within 80±5℃,the oil temperature within 95±5℃,and the intake air temperature within 30±2℃.[Results and Conclusions]The results of this study are the following:① The power of the gasoline engine showed a linear growth trend with increasing torque,and this enhancement rate increased with higher engine speeds.A higher percentage of methanol gasoline(M85)exhibited higher fuel consumption than 92 octane gasoline under the same working conditions owing to its lower heat density,with the highest fuel consumption being more than 50% that of 92 octane gasoline.② Isopropanol cylinder pressure at high rpm and lower loads is affected by the amount of fuel injected,which can be erratic at peaks,and the higher the rpm,the higher the demand for isopropanol fuel.③ Combustion of a 50% isopropanol blended fuel intensified near 1° CA,whereas gasoline began to burn near 3° CA,with combustion lasting longer.
万方数据
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