發(fā)布時間：2018-01-20 13:37

  本文關(guān)鍵詞： 對置活塞對置氣缸發(fā)動機 缸內(nèi)流動 換氣過程 燃燒過程　出處：《中北大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：OPOC（對置活塞對置氣缸）發(fā)動機是一種新型結(jié)構(gòu)的二沖程發(fā)動機，具有結(jié)構(gòu)緊湊、效率高、功率密度大、整機平衡性好、布置方式靈活等優(yōu)點，擁有廣闊的應(yīng)用前景。OPOC發(fā)動機雖然采用了直流掃氣、電控噴油、電動增壓等技術(shù)，但作為二沖程發(fā)動機其仍存在著換氣質(zhì)量不高、燃燒不充分等問題。 本文在已有研究基礎(chǔ)上，詳細分析了不同氣口結(jié)構(gòu)下的缸內(nèi)流動狀況對OPOC發(fā)動機換氣及燃燒過程的影響。 文章首先計算了OPOC發(fā)動機氣缸內(nèi)外兩活塞的具體運動規(guī)律，進而得到了OPOC發(fā)動機的缸內(nèi)容積以及進排氣口流通面積的變化情況，在此基礎(chǔ)上設(shè)置合理的燃燒參數(shù)，建立了OPOC發(fā)動機的一維工作過程仿真模型，得到了發(fā)動機不同轉(zhuǎn)速下的進排氣壓力、掃氣效率、缸內(nèi)壓力等參數(shù)。 基于一維仿真結(jié)果設(shè)定邊界條件，建立OPOC發(fā)動機換氣過程的三維仿真模型，分別對3600r/min、2500r/min以及1600r/min三種轉(zhuǎn)速下的換氣過程進行分析，對比不同轉(zhuǎn)速下的缸內(nèi)瞬態(tài)流場以及殘余廢氣分布的變化情況。通過分析發(fā)現(xiàn)：在原進排氣口結(jié)構(gòu)作用下所形成的缸內(nèi)流動形式并不合理，高速工況下掃氣質(zhì)量較差。 在原進氣口模型5°/15°傾角的基礎(chǔ)上，分別設(shè)計了10°/20°、15°/30°、20°/40°三種不同的改進方案，并對三種掃氣方案在不同轉(zhuǎn)速下的缸內(nèi)流動、廢氣殘留等情況進行了分析。為使發(fā)動機在整個工作轉(zhuǎn)速范圍內(nèi)都能具有較高的掃氣質(zhì)量，文章最終選擇了15°/30°作為最終的優(yōu)化方案。 為進一步研究所選定的15°/30°優(yōu)化方案對整機性能的影響，文章對15°/30°方案與原方案在3600r/min下的燃燒過程進行了分析。為保證分析的準(zhǔn)確性，建立起了包括換氣過程與燃燒過程的發(fā)動機整個工作過程的仿真模型。通過與原方案的燃燒過程對比分析發(fā)現(xiàn)：所選擇的最終優(yōu)化方案，缸內(nèi)流動形式更加合理，，在一定程度上加快了燃油的蒸發(fā)與霧化，同時可燃混合氣分布更加均勻，燃燒過程更加迅速。最終通過對整個工作過程的P-V曲線計算發(fā)現(xiàn)，改進方案的發(fā)動機功率更大、油耗更低。
[Abstract]:OPOC engine is a new type of two-stroke engine, which has the advantages of compact structure, high efficiency, high power density, good balance and flexible arrangement. The OPOC engine has a broad application prospect. Although the OPOC engine adopts DC scavenging, electronically controlled fuel injection, electric supercharging and other technologies, but as a two-stroke engine, it still has a low air exchange quality. Insufficient combustion, etc. On the basis of the previous studies, the influence of the in-cylinder flow conditions on the air exchange and combustion process of the OPOC engine with different air orifice structures is analyzed in detail in this paper. This paper first calculates the specific motion law of the two pistons inside and outside the cylinder of OPOC engine, and then obtains the change of the cylinder volume and the flow area of the intake and exhaust port of the OPOC engine. On the basis of setting reasonable combustion parameters, the one-dimensional working process simulation model of OPOC engine is established, and the parameters such as inlet and exhaust pressure, scavenging efficiency and in-cylinder pressure are obtained. Based on the one-dimensional simulation results, a three-dimensional simulation model of the OPOC engine ventilation process was established. The air exchange process was analyzed at three rotational speeds: 2500r-min and 1600r-min. By comparing the change of transient flow field and residual exhaust gas distribution in cylinder at different speeds, it is found that the flow form in cylinder formed under the action of the original inlet and exhaust port structure is not reasonable. The scavenging quality is poor at high speed. Based on the 5 擄/ 15 擄inclination of the original inlet model, three different improvement schemes were designed for 10 擄/ 20 擄/ 15 擄/ 30 擄/ 20 擄/ 40 擄respectively. In order to make the engine have a higher scavenging quality in the whole working speed range, the flow in cylinder and the residue of exhaust gas are analyzed under different rotating speed of three kinds of scavenging schemes. Finally, 15 擄/ 30 擄is chosen as the final optimization scheme. In order to further study the effect of the selected 15 擄/ 30 擄optimization scheme on the performance of the whole machine. In this paper, the combustion process of the 15 擄/ 30 擄scheme and the original scheme at 3600r / min is analyzed to ensure the accuracy of the analysis. The simulation model of the whole working process of the engine including the air exchange process and the combustion process is established. Through the comparison and analysis of the combustion process with the original scheme, it is found that the final optimization scheme is selected. The flow pattern in the cylinder is more reasonable, which speeds up the evaporation and atomization of the fuel to a certain extent, and the distribution of the combustible mixture is more uniform at the same time. Finally, the P-V curve of the whole working process is calculated and it is found that the improved scheme has higher engine power and lower fuel consumption.
【學(xué)位授予單位】：中北大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TK421

【參考文獻】

相關(guān)期刊論文 前10條

1 劉長振;劉廣豐;郝勇剛;李建新;;雙對置二沖程柴油機性能分析方法探討[J];柴油機;2012年01期

2 劉書亮,孫曉燕,史紹熙,馮明志,李康;四氣門汽油機中滾流運動的三維數(shù)值模擬[J];工程熱物理學(xué)報;1999年01期

3 強永平;李耀宗;白洪林;劉瑋;文明;袁偉;賈曉亮;;組合噴射對雙對置二沖程發(fā)動機燃燒過程影響的計算研究[J];車用發(fā)動機;2014年05期

4 陳文婷;諸葛偉林;張揚軍;于紅勝;;雙對置二沖程柴油機掃氣過程仿真研究[J];航空動力學(xué)報;2010年06期

5 杜巍,向繼紅,李向榮;用RES3D-Ⅱ程序?qū)?2150ZL柴油機燃燒過程進行數(shù)值模擬的研究[J];內(nèi)燃機工程;2000年03期

6 孫濟美,牟永泉,董愚,陸孝寬;發(fā)動機模型進氣道內(nèi)氣體流場的模擬和實驗研究[J];內(nèi)燃機學(xué)報;1989年02期

7 常思勤,劉雪洪,何小明;現(xiàn)代設(shè)計方法在螺旋進氣道設(shè)計中的應(yīng)用[J];內(nèi)燃機學(xué)報;1999年04期

8 許漢君;宋金甌;姚春德;劉長振;于紅勝;郝勇剛;王清旭;;對置二沖程柴油機缸內(nèi)流動形式對混合氣形成及燃燒的模擬研究[J];內(nèi)燃機學(xué)報;2009年05期

9 趙曉輝;張翼;許俊峰;;OPOC發(fā)動機研究綜述[J];內(nèi)燃機與配件;2012年11期

10 章振宇;趙振峰;張付軍;趙長祿;王斌;;對置二沖程柴油機掃氣口參數(shù)對掃氣過程的影響[J];內(nèi)燃機工程;2014年05期

本文編號：1448378