發(fā)布時(shí)間：2018-08-14 10:46

【摘要】：隨著交通道路的改善及汽車大型化，汽車速度及載重能力得到了很大提高，現(xiàn)代汽車對(duì)制動(dòng)性能提出了越來越高的要求,在現(xiàn)代商用車特別是大型商用車上增加輔助制動(dòng)裝置已成為一種趨勢(shì)甚至成為硬性規(guī)定，發(fā)動(dòng)機(jī)泄氣制動(dòng)作為一種重要的輔助制動(dòng)系統(tǒng)，在國外已有較多應(yīng)用，它大大增加了行車安全性。由于國外對(duì)先進(jìn)技術(shù)及資料的保密，國內(nèi)對(duì)輔助制動(dòng)能力利用水平一直停留在排氣制動(dòng)階段，對(duì)制動(dòng)效果更好制動(dòng)性能更優(yōu)的泄氣式輔助制動(dòng)的研究、生產(chǎn)和應(yīng)用還處于起步階段，對(duì)泄氣制動(dòng)性能也缺乏系統(tǒng)的研究。 本文在國內(nèi)外對(duì)發(fā)動(dòng)機(jī)輔助制動(dòng)技術(shù)研究的基礎(chǔ)上，對(duì)發(fā)動(dòng)機(jī)泄氣式輔助制動(dòng)的相關(guān)技術(shù)進(jìn)行了深入的分析和研究。運(yùn)用三維數(shù)值模擬與實(shí)驗(yàn)相結(jié)合的方法對(duì)發(fā)動(dòng)機(jī)泄氣式輔助制動(dòng)的工作過程及制動(dòng)性能進(jìn)行了研究，不但顯示了活塞壓力的變化過程，而且得出了各狀態(tài)下平均制動(dòng)功率的大小，，通過優(yōu)化工作參數(shù)提高了制動(dòng)性能，最后利用臺(tái)架試驗(yàn)驗(yàn)證了模擬方法的正確性，為將來開發(fā)具有自主知識(shí)產(chǎn)權(quán)且制動(dòng)性能優(yōu)良的泄氣制動(dòng)器提供參考依據(jù)。 本文以校企合作項(xiàng)目為依托，對(duì)發(fā)動(dòng)機(jī)泄氣式輔助制動(dòng)進(jìn)行了研究。論文的主要研究工作和創(chuàng)新之處如下： （1）建立了發(fā)動(dòng)機(jī)泄氣制動(dòng)數(shù)學(xué)模型，并根據(jù)某發(fā)動(dòng)機(jī)原型建立了三維模型，對(duì)發(fā)動(dòng)機(jī)泄氣制動(dòng)過程進(jìn)行了三維數(shù)值模擬，研究了發(fā)動(dòng)機(jī)泄氣制動(dòng)工作時(shí)活塞壓力及發(fā)動(dòng)機(jī)泄氣制動(dòng)功率的變化情況。 （2）通過數(shù)值模擬分析了相關(guān)參數(shù)（包括排氣門開度、發(fā)動(dòng)機(jī)轉(zhuǎn)速和排氣背壓等）對(duì)活塞受力及發(fā)動(dòng)機(jī)泄氣制動(dòng)性能的影響。對(duì)泄氣制動(dòng)裝置關(guān)鍵部件進(jìn)行了受力與可靠性分析，保證在制動(dòng)性能優(yōu)化過程中相關(guān)制動(dòng)機(jī)構(gòu)不會(huì)破壞。 （3）對(duì)數(shù)值模擬結(jié)果進(jìn)行了實(shí)驗(yàn)驗(yàn)證，結(jié)果表明：實(shí)驗(yàn)值與模擬值誤差很小，模擬計(jì)算方法合理，結(jié)果可信。模擬方法和結(jié)論可用于發(fā)動(dòng)機(jī)泄氣制動(dòng)的相關(guān)設(shè)計(jì)和性能研究。根據(jù)研究結(jié)果提出了提高發(fā)動(dòng)機(jī)泄氣制動(dòng)性能的方案，通過優(yōu)化相關(guān)參數(shù)提高發(fā)動(dòng)機(jī)泄氣制動(dòng)性能。
[Abstract]:With the improvement of the traffic road and the large-scale automobile, the vehicle speed and load capacity have been greatly improved, and the modern automobile has put forward more and more high requirements for the braking performance. It has become a trend to add auxiliary braking devices to modern commercial vehicles, especially in large commercial vehicles. As an important auxiliary braking system, engine exhaust braking has been widely used abroad. It greatly increases the safety of driving. Because of the secrecy of advanced technology and data in foreign countries, the utilization level of auxiliary braking capacity in China has been staying at the stage of exhaust braking, and the research on the exhaust auxiliary brake with better braking effect and better braking performance has been carried out in our country. The production and application are still in the initial stage, and there is a lack of systematic research on the performance of deflated braking. Based on the research of engine auxiliary braking technology at home and abroad, this paper makes a deep analysis and research on the relevant technology of engine exhaust auxiliary brake. The working process and braking performance of engine exhaust auxiliary brake are studied by using the method of three-dimensional numerical simulation and experiment, which not only shows the process of piston pressure variation. Moreover, the average braking power in each state is obtained, and the braking performance is improved by optimizing the working parameters. Finally, the correctness of the simulation method is verified by the bench test. It provides a reference for the future development of deflator brake with independent intellectual property rights and excellent braking performance. In this paper, based on the school-enterprise cooperation project, the engine exhaust auxiliary brake is studied. The main research work and innovations are as follows: (1) the mathematical model of engine exhaust braking is established, and a three-dimensional model is established according to an engine prototype, and the three-dimensional numerical simulation of engine exhaust braking process is carried out. The variation of piston pressure and engine exhaust brake power during engine exhaust braking is studied. (2) the relevant parameters (including the opening of exhaust valve) are analyzed by numerical simulation. The influence of engine speed and exhaust back pressure on the piston force and the performance of engine exhaust brake. The stress and reliability analysis of the key parts of the deflating braking device are carried out to ensure that the relevant braking mechanism will not be destroyed in the process of braking performance optimization. (3) the experimental results are verified by the numerical simulation results. The results show that the error between the experimental value and the simulated value is very small, the simulation calculation method is reasonable and the results are credible. The simulation method and conclusion can be used in the design and performance study of engine exhaust brake. According to the research results, a scheme to improve the performance of engine exhaust braking is put forward, and the performance of engine exhaust braking is improved by optimizing the relevant parameters.
【學(xué)位授予單位】：湖南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：U463.5;U467

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本文編號(hào)：2182611