【摘要】：本文以167FML汽油機(jī)為研究對(duì)象,通過(guò)相關(guān)試驗(yàn)測(cè)試建立其一維熱力學(xué)數(shù)值仿真模型,在模型校驗(yàn)的基礎(chǔ)上,根據(jù)開(kāi)發(fā)目標(biāo)對(duì)發(fā)動(dòng)機(jī)性能進(jìn)行了分析優(yōu)化。同時(shí),針對(duì)產(chǎn)品開(kāi)發(fā)過(guò)程中出現(xiàn)的各種故障模式,利用循環(huán)模擬數(shù)值方法進(jìn)行了診斷分析,并提出了相應(yīng)改善措施。本文具體工作內(nèi)容如下:首先結(jié)合大量試驗(yàn)測(cè)試,包括發(fā)動(dòng)機(jī)臺(tái)架試驗(yàn)、空燃比測(cè)試、氣道穩(wěn)流試驗(yàn)、氣門(mén)升程測(cè)試、熱反拖試驗(yàn)、空濾器進(jìn)氣特性試驗(yàn)、以及動(dòng)態(tài)壓力測(cè)量等,詳細(xì)闡述了167FML汽油機(jī)一維熱力學(xué)模型建立過(guò)程。模型經(jīng)過(guò)校正,模擬值與試驗(yàn)值誤差均在5%以?xún)?nèi),所建模型能準(zhǔn)確反映發(fā)動(dòng)機(jī)的工作特征,具有較高的可信度。根據(jù)開(kāi)發(fā)目標(biāo),基于構(gòu)建的BOOST模型,模擬分析了不同進(jìn)排氣系統(tǒng)結(jié)構(gòu)以及配氣正時(shí)對(duì)167FML汽油機(jī)動(dòng)力性能的影響,并選擇性的提出將進(jìn)氣晚關(guān)角提前20DegCA的優(yōu)化方案,試驗(yàn)驗(yàn)證該方案具有明顯提升發(fā)動(dòng)機(jī)低速扭矩的效果,5000r/min提升約10.63%,因此被應(yīng)用于最終產(chǎn)品設(shè)計(jì);針對(duì)發(fā)動(dòng)機(jī)優(yōu)化過(guò)程中出現(xiàn)的熱負(fù)荷過(guò)高的問(wèn)題,選取兩款散熱良好的缸頭,利用循環(huán)模擬方法對(duì)氣道結(jié)構(gòu)變更對(duì)其性能的影響進(jìn)行了預(yù)測(cè)分析,試驗(yàn)結(jié)果表明新缸頭下發(fā)動(dòng)機(jī)熱負(fù)荷大大降低,機(jī)油溫度下降明顯,且發(fā)動(dòng)機(jī)最大扭矩提升約5.3%;此外,考慮到整車(chē)布置以及發(fā)動(dòng)機(jī)性能目標(biāo),利用數(shù)值模擬方法結(jié)合試驗(yàn)測(cè)試對(duì)消聲器進(jìn)行了重新匹配,并使最大扭矩提升6.9%。應(yīng)用構(gòu)建的熱力學(xué)模型及相關(guān)試驗(yàn)測(cè)試,對(duì)發(fā)動(dòng)機(jī)開(kāi)發(fā)過(guò)程中出現(xiàn)的各種故障模式進(jìn)行了診斷分析:針對(duì)新缸頭發(fā)動(dòng)機(jī)出現(xiàn)的高速不穩(wěn)定問(wèn)題,文中從模擬缸內(nèi)殘余廢氣系數(shù)及燃燒測(cè)試試驗(yàn)兩方面入手,分析了其可能產(chǎn)生的原因;其次,對(duì)于樣機(jī)無(wú)二次補(bǔ)氣狀態(tài)下怠速不穩(wěn)的問(wèn)題,建立帶二次補(bǔ)氣的一維熱力學(xué)模型進(jìn)行對(duì)比,分析了二次補(bǔ)氣對(duì)缸內(nèi)殘余廢氣率的影響,并提出排氣相位整體提前10DegCA的改善措施;此外,針對(duì)樣機(jī)配氣機(jī)構(gòu)存在的噪聲問(wèn)題,提出增加凸輪緩沖段的改善措施,并模擬分析了進(jìn)排氣凸輪不同緩沖段設(shè)計(jì)方案對(duì)發(fā)動(dòng)機(jī)性能的影響,進(jìn)而給出設(shè)計(jì)建議。
[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.
【學(xué)位授予單位】：重慶大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：TK411

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本文編號(hào)：2364415