小型车用高速柴油机工作过程模拟计算及试验研究

【作者】 刘灵；

【导师】 沈颖刚；

【作者基本信息】 昆明理工大学 ， 动力机械及工程， 2011， 硕士

【摘要】 随着社会的快速发展,能源与环境问题也引起了当今社会的高度关注。这对内燃机动力性、经济性及排放性提出了越来越高的要求。通过利用计算机对内燃机工作过程的仿真计算和整机试验相结合的方法,可以缩短产品更新周期、节省人力及物力,这是目前改善和提高发动机的经济性、动力性、排放性最好方式。本文开展了以下三个方面的研究工作：1)对发动机各物理子系统建立工作过程数值模型,并在此基础上通过利用大型的通用内燃机工作过程数值模拟软件GT-Power,建立了D19TCI涡轮增压柴油发动机的GT-Power模型,并通过模型计算结果和D19TCI柴油发动机的试验数据的对比验证建立模型的准确性。2)通过所建立的D19TCI模型,模拟计算不同喷油提前角、增减喷油量、进气增压压力及不同摩擦系数对发动机性能影响。3)通过改变D19TCI柴油发动机实机的喷油提前角、增减喷油量、外源进气增压及不同的润滑油对发动机性能影响试验。通过模拟结果和试验数据进行对比分析得出,在不同转速工况时都有使得发动机的动力性及经济性最优的一个最佳喷油提前角；试验值的曲线发展趋势和模拟计算结果表明喷油量为循环油量为70mg时发动机动力性及经济性最优；不同的进排气压力对发动机性能影响是很明显的。进气压力在一定范围内,随着压力的增大有利于发动机的动力性及经济性的改善和提高。反之,超出范围后压力越大则对发动机性能不利影响也会越大；无论在任何工况,摩擦系数越大,发动机的动力性及经济性就越差,随着转速的增加,影响会越来越明显。润滑油粘度过大或过小都会影响到发动机的动力性及经济性,粘度过大,发动机工作时要克服润滑油内部的摩擦,因此会消耗一部分功率使得有效功率下降,燃油消耗也会随之增加；粘度过小使得承载油膜不够会造成磨损过大,造成发动机的动力性及经济性下降等。更多还原

【Abstract】 With the rapid development of society, energy crisis and environmental problems cause great concern, which are given higher and higher requirements for the dynamic, economy and emission performance of ICE. Research on the working process of ICE is one of the most effective way to solve these problems for renewing production and saving manpower and material resources.Now it is the best way of improving the dynamic, economy and emissions performance of ICE through combining process simulation on computer and experiments.This paper carried out three aspects of research as follows:1) Establishing a numerical model of working process for all ICE subsystems and then set up a model of D19TCI-Turbocharged diesel engine based on software such as GT-Power. The accuracy of modeling was verified by comparing the simulation results and experimental data.2) Changing the injection timing\Fuel injection quantity\pressure behind turbo charger and Friction coefficient to research their effects on performance of ICE on the D19TCI model.3) Carrying out experiment on the performance of D19TCI-Turbocharged diesel engine by altering injection timing\Fuel injection quantity\pressure after turbo-charger and by changing different types of LO.Through comparing the simulation results and experimental data we can see: There is an optimum injection advance angle at each speed to get the optimum dynamic and economy performance; the experimental and simulation results show that dynamic and economy performance reach the optimum value when the oil injection is at the amount of 70mg; the influences of different intake and exhaust pressure on the engine performance are obvious. Within a certain range, the increasing of inlet pressure results in a gainful increase of the dynamic and economy performance while without the range to a converse condition. In all condition, the dynamic and economy performance gets poorer as economy performance. The Friction coefficient become larger, Oil viscosity affects the engine dynamic and economy performance whether too large or too small. Too large Viscosity consumes a part of the power and decreases the effective power because the engine has to solve the internal friction of LO when working, which leads to more fuel consumption; too small viscosity leads to insufficient oil film and excessive wear which will result in bad dynamic and economy performance.更多还原