【摘要】：燃油噴射系統(tǒng)對柴油機的動力性、經(jīng)濟性、排放性和NVH具有十分重要的影響。作為燃油系統(tǒng)的核心部件,電控噴油器的結(jié)構(gòu)與性能參數(shù)選擇對噴油過程、噴霧質(zhì)量、以及混合氣的形成和燃燒有重要的影響。本文基于生產(chǎn)實踐中高壓共軌系統(tǒng)電控噴油器匹配的技術(shù)需求展開研究,旨在使電控噴油器的選型評估更加全面、細致,使電控噴油器的匹配更加高效、精確。對結(jié)構(gòu)尺寸相同,由不同廠家加工的兩組噴油器進行測試,兩組噴油器的組內(nèi)噴油器間油量差異區(qū)別較大。發(fā)動機外特性試驗結(jié)果表明兩組噴油器油量特征差異導(dǎo)致了發(fā)動機性能的不同。負荷特性試驗結(jié)果表明發(fā)動機采用廠家1噴油器時的油耗低于采用廠家2噴油器時的油耗,該優(yōu)勢在小負荷區(qū)域更加明顯。在大部分外特性工況點采用廠家2噴油器時的煙度值均高于采用廠家1噴油器時的煙度值。針對四種不同的電控噴油器,在不同軌壓、不同加電時間下測量了噴油持續(xù)期,分析了噴油持續(xù)期與加電時間之差,得出相同工況下、不同噴油器的噴油持續(xù)期和加電時間之差差別不大,并對四種噴油持續(xù)期做了平均。采用基于最小二乘法的曲面擬合方法對平均后的噴油持續(xù)器進行擬合,得到噴油持續(xù)期關(guān)于軌壓和加電時間的表達式,結(jié)果表明:93.9%的噴油持續(xù)期試驗數(shù)據(jù)點同擬合結(jié)果的差異在±120?s的范圍內(nèi)。采用理論計算評估燃油噴射功耗,將燃油噴射功耗分為霧化功耗和壓力損失功耗,對影響計算精度的噴孔流量系數(shù)做了深入分析。對靜態(tài)泄漏功耗進行了理論和試驗分析,結(jié)果表明理論結(jié)果與試驗結(jié)果在重點關(guān)注的高軌壓區(qū)域保持了很好的一致性。采用理論結(jié)合試驗的方法評估液力控制功耗和電力驅(qū)動功耗。對某柴油機大扭矩點和額定點噴油器功耗的評估顯示用于霧化功耗約占總功耗的40%,通過噴油器結(jié)構(gòu)優(yōu)化可以使發(fā)動機油耗降低的幅度小于1.0g/(kWh)。通過試驗研究了電控噴油器多次噴射油量特征,結(jié)果表明燃油壓力波動導(dǎo)致了兩次噴射模式下第二次噴射油量隨兩次噴射間隔的變化。每個軌壓下都存在多次噴射油量偏差幅度最大的情況,最大接近±50%。絕對油量偏差幅度隨第二次噴射標準油量和軌壓的增大而增大;相對偏差范圍隨第二次噴射標準油量的增大而減小。噴油器入口處壓力波動與第二次噴射油量隨兩次噴射間隔變化的周期相同。結(jié)構(gòu)尺寸不同的兩種噴油器的第二次噴射油量偏差幅度差異較大。
[Abstract]:Fuel injection system has a very important influence on the power, economy, emission and NVH of diesel engine. As the core component of the fuel system, the structure and performance parameters of the electronic control injector have an important influence on the injection process, spray quality, and the formation and combustion of the mixture. In this paper, based on the technical requirements of electronic control injector matching in high pressure common rail system, the purpose of this paper is to make the selection and evaluation of electronic control injector more comprehensive and detailed, and to make the matching of electronic control injector more efficient and accurate. The two groups of injectors processed by different manufacturers are tested for the same structure size, and the oil quantity difference between the two groups of injectors is quite different. The results of engine external characteristic test show that the difference of fuel quantity characteristics between the two groups of injectors leads to the difference of engine performance. The results of load characteristic test show that the fuel consumption of the engine with manufacturer 1 injector is lower than that when manufacturer 2 injector is used, and the advantage is more obvious in the low load area. When the manufacturer 2 injector is used in most of the external characteristic working conditions, the smoke value is higher than that when the manufacturer 1 injector is used. According to four different kinds of electronic control injectors, the injection duration is measured under different rail pressure and different power-up time, the difference between injection duration and power-up time is analyzed, and the same working conditions are obtained. There is no significant difference between the injection duration and the charging time of different injectors, and the four injection duration are averaged. The surface fitting method based on the least square method is used to fit the average fuel injector, and the expressions of the fuel injection duration about rail pressure and power up time are obtained. The results show that the difference between 93.9% of the fuel injection duration test data points and the fitting results is in the range of 鹵120 鈮，

本文編號：2480912