CAJ | 학술논문

根据“高密度-低温燃烧”方案匹配的两级增压系统，使重型柴油机在中低速能实现低排放和高有效热效率。然而，在高速中高负荷工况，增压系统不经过必要的调压手段，会存在排气背压过高的问题，从而使柴油机油耗和烟度均较高，有效热效率较低。为此，本文采用后喷技术和涡端放气技术，通过分析后喷定时、主后喷油量比例和进气压力等参数对排放和有效热效率的影响，得到油路参数与气路参数的协同优化控制方法。研究表明，在高涡前压力工况，相比单次喷射模式，采用“主喷＋后喷”的喷油模式，能实现更低排放，但有效热效率会下降。进一步研究发现，随着后喷定时和主后喷油量比例的变化，存在一个适当的后喷定时和后喷油量区间，使缸内碳烟易于降低。同时，随着涡端旁通阀开度增加，NOx排放会不断减小，碳烟排放会出现一个拐点，呈现先减小后增加的趋势，而有效热效率则逐渐增加。这充分说明，在高涡前压力工况，适时放气，能同时改善排放和有效热效率。
근거“고밀도-저온연소”방안필배적량급증압계통，사중형시유궤재중저속능실현저배방화고유효열효솔。연이，재고속중고부하공황，증압계통불경과필요적조압수단，회존재배기배압과고적문제，종이사시유궤유모화연도균교고，유효열효솔교저。위차，본문채용후분기술화와단방기기술，통과분석후분정시、주후분유량비례화진기압력등삼수대배방화유효열효솔적영향，득도유로삼수여기로삼수적협동우화공제방법。연구표명，재고와전압력공황，상비단차분사모식，채용“주분＋후분”적분유모식，능실현경저배방，단유효열효솔회하강。진일보연구발현，수착후분정시화주후분유량비례적변화，존재일개괄당적후분정시화후분유량구간，사항내탄연역우강저。동시，수착와단방통벌개도증가，NOx배방회불단감소，탄연배방회출현일개괴점，정현선감소후증가적추세，이유효열효솔칙축점증가。저충분설명，재고와전압력공황，괄시방기，능동시개선배방화유효열효솔。
Low emissions and high brake thermal efficiency could be achieved in medium and low speed condition by the heavy-duty diesel engine with two-stage turbocharging system based on the high-density low temperature combus-tion theory. However,if the turbocharging system had none pressure regulation means,the exhaust backpressure would be so high that the fuel consumption and smoke intensity of the diesel engine would be relatively high and the brake thermal efficiency would be relatively low in high speed,medium and high load conditions. So post injection and turbo-side deflating technology was used in this paper,and the control method of collaborative optimization of oil and gas parameters could be achieved by analyzing the parameters of post injection timing,fuel quantity propor-tion of main and post injection and intake pressure. The study showed that compared to single injection mode,the main and post injection mode could achieve lower emissions,but worse brake thermal efficiency in high backpres-sure conditions. Further studies showed that it would be easier to reduce soot emission in an appropriate interval of post injection timing and post injection quantity. At the same time,the NOx emission would continue to decrease,the soot emission would have an inflection point showing a trend of first increase and then decrease,and the brake ther-mal efficiency would increase gradually. This fully showed that emissions and brake thermal efficiency could be im-proved by opportunely turbo-side deflating in high backpressure conditions.