167FML汽油机一维热力学模型及其应用
发布时间：2018-11-29 08:01
【摘要】：本文以167FML汽油机为研究对象,通过相关试验测试建立其一维热力学数值仿真模型,在模型校验的基础上,根据开发目标对发动机性能进行了分析优化。同时,针对产品开发过程中出现的各种故障模式,利用循环模拟数值方法进行了诊断分析,并提出了相应改善措施。本文具体工作内容如下:首先结合大量试验测试,包括发动机台架试验、空燃比测试、气道稳流试验、气门升程测试、热反拖试验、空滤器进气特性试验、以及动态压力测量等,详细阐述了167FML汽油机一维热力学模型建立过程。模型经过校正,模拟值与试验值误差均在5%以内,所建模型能准确反映发动机的工作特征,具有较高的可信度。根据开发目标,基于构建的BOOST模型,模拟分析了不同进排气系统结构以及配气正时对167FML汽油机动力性能的影响,并选择性的提出将进气晚关角提前20DegCA的优化方案,试验验证该方案具有明显提升发动机低速扭矩的效果,5000r/min提升约10.63%,因此被应用于最终产品设计;针对发动机优化过程中出现的热负荷过高的问题,选取两款散热良好的缸头,利用循环模拟方法对气道结构变更对其性能的影响进行了预测分析,试验结果表明新缸头下发动机热负荷大大降低,机油温度下降明显,且发动机最大扭矩提升约5.3%;此外,考虑到整车布置以及发动机性能目标,利用数值模拟方法结合试验测试对消声器进行了重新匹配,并使最大扭矩提升6.9%。应用构建的热力学模型及相关试验测试,对发动机开发过程中出现的各种故障模式进行了诊断分析:针对新缸头发动机出现的高速不稳定问题,文中从模拟缸内残余废气系数及燃烧测试试验两方面入手,分析了其可能产生的原因;其次,对于样机无二次补气状态下怠速不稳的问题,建立带二次补气的一维热力学模型进行对比,分析了二次补气对缸内残余废气率的影响,并提出排气相位整体提前10DegCA的改善措施;此外,针对样机配气机构存在的噪声问题,提出增加凸轮缓冲段的改善措施,并模拟分析了进排气凸轮不同缓冲段设计方案对发动机性能的影响,进而给出设计建议。
[Abstract]:In this paper, the one-dimensional thermodynamic numerical simulation model of 167FML gasoline engine is established by relevant test and test. Based on the verification of the model, the engine performance is analyzed and optimized according to the development goal. At the same time, according to the various fault modes in the process of product development, the cyclic simulation numerical method is used to diagnose and analyze, and the corresponding improvement measures are put forward. The main contents of this paper are as follows: firstly, combined with a large number of tests, including engine bench test, air-fuel ratio test, port steady flow test, valve lift test, thermal reverse drag test, air filter intake characteristic test, The establishment of one-dimensional thermodynamic model of 167FML gasoline engine is described in detail as well as dynamic pressure measurement. The model is corrected and the error between the simulated value and the experimental value is less than 5%. The established model can accurately reflect the working characteristics of the engine and has a high reliability. According to the development goal, based on the BOOST model, the influence of different intake and exhaust system structure and timing on the dynamic performance of 167FML gasoline engine is simulated and analyzed. The experimental results show that this scheme can obviously improve the engine torque at low speed. The 5000r/min is raised about 10.63, so it is used in the final product design. Aiming at the problem of excessive heat load in the process of engine optimization, two cylinder heads with good heat dissipation are selected, and the influence of structural changes of air ports on their performance is predicted and analyzed by cyclic simulation method. The test results show that the heat load of the engine under the new cylinder head is greatly reduced, the engine oil temperature is obviously decreased, and the maximum torque of the engine is increased by about 5.3 percent. In addition, considering the vehicle layout and engine performance target, the muffler is rematched by numerical simulation method and test, and the maximum torque is increased by 6.9%. Based on the thermodynamics model and related test, various fault modes in engine development are diagnosed and analyzed. The problem of high speed instability of new cylinder head engine is analyzed. In this paper, the possible causes of residual exhaust gas coefficient in cylinder and combustion test are analyzed. Secondly, the one-dimensional thermodynamic model with secondary gas supply is established to compare the idle instability of the prototype without secondary gas supply, and the influence of secondary gas supply on the residual exhaust rate in cylinder is analyzed. At the same time, the improvement measures of overall advance 10DegCA of exhaust phase are put forward. In addition, in view of the noise problem of the valve distribution mechanism of the prototype, the improvement measures of increasing the cam buffer section are put forward, and the influence of different design schemes of the intake and exhaust cam on the engine performance is simulated and analyzed, and the design suggestions are given.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK411
本文编号：2364415
[Abstract]:In this paper, the one-dimensional thermodynamic numerical simulation model of 167FML gasoline engine is established by relevant test and test. Based on the verification of the model, the engine performance is analyzed and optimized according to the development goal. At the same time, according to the various fault modes in the process of product development, the cyclic simulation numerical method is used to diagnose and analyze, and the corresponding improvement measures are put forward. The main contents of this paper are as follows: firstly, combined with a large number of tests, including engine bench test, air-fuel ratio test, port steady flow test, valve lift test, thermal reverse drag test, air filter intake characteristic test, The establishment of one-dimensional thermodynamic model of 167FML gasoline engine is described in detail as well as dynamic pressure measurement. The model is corrected and the error between the simulated value and the experimental value is less than 5%. The established model can accurately reflect the working characteristics of the engine and has a high reliability. According to the development goal, based on the BOOST model, the influence of different intake and exhaust system structure and timing on the dynamic performance of 167FML gasoline engine is simulated and analyzed. The experimental results show that this scheme can obviously improve the engine torque at low speed. The 5000r/min is raised about 10.63, so it is used in the final product design. Aiming at the problem of excessive heat load in the process of engine optimization, two cylinder heads with good heat dissipation are selected, and the influence of structural changes of air ports on their performance is predicted and analyzed by cyclic simulation method. The test results show that the heat load of the engine under the new cylinder head is greatly reduced, the engine oil temperature is obviously decreased, and the maximum torque of the engine is increased by about 5.3 percent. In addition, considering the vehicle layout and engine performance target, the muffler is rematched by numerical simulation method and test, and the maximum torque is increased by 6.9%. Based on the thermodynamics model and related test, various fault modes in engine development are diagnosed and analyzed. The problem of high speed instability of new cylinder head engine is analyzed. In this paper, the possible causes of residual exhaust gas coefficient in cylinder and combustion test are analyzed. Secondly, the one-dimensional thermodynamic model with secondary gas supply is established to compare the idle instability of the prototype without secondary gas supply, and the influence of secondary gas supply on the residual exhaust rate in cylinder is analyzed. At the same time, the improvement measures of overall advance 10DegCA of exhaust phase are put forward. In addition, in view of the noise problem of the valve distribution mechanism of the prototype, the improvement measures of increasing the cam buffer section are put forward, and the influence of different design schemes of the intake and exhaust cam on the engine performance is simulated and analyzed, and the design suggestions are given.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK411
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