广西大学学报(自然科学版)
廣西大學學報(自然科學版)
엄서대학학보(자연과학판)
Journal of Guangxi University (Natural Science Edition)
2015年
5期
1135-1145
,共11页
官维%莫春兰%赵刚东%黄冠衍%郑尊清
官維%莫春蘭%趙剛東%黃冠衍%鄭尊清
관유%막춘란%조강동%황관연%정존청
柴油机%废气再循环(EGR)%两级增压%燃烧室%喷油策略%排放
柴油機%廢氣再循環(EGR)%兩級增壓%燃燒室%噴油策略%排放
시유궤%폐기재순배(EGR)%량급증압%연소실%분유책략%배방
diesel engine%exhaust gas recirculation ( EGR)%two-stage turbocharger%combustion chamber%injection strategy%emissions
为了满足今后更为苛刻的国V排放法规,本文在一台无后处理满足国Ⅳ排放的重型柴油机上进行了燃烧系统优化试验,结果表明在大多数工况点,低压级压气机有效流通面积减小的两级增压方案2TC2与柴油机的联合运行点向着压比和相似流量增大的方向移动,能明显提高进气压力和空燃比,有效改善了氮氧化物( NOx)与燃油消耗率( BSFC)以及NOx与碳烟( Soot)的权衡( trade-off)关系。通过优化设计燃烧室结构参数(缩口直径、凹坑深度),缩口下移1 mm的燃烧室SF4能增强缸内气流运动,促进了燃油与空气的混合,实现了同时改善NOx-Soot和NOx-BSFC的trade-off关系并维持缸内最大燃烧压力至合理水平。随着主喷时刻的推迟,燃烧相位推迟,Soot比排放降低,但燃油经济性变差,并且主喷时刻过多推迟会使Soot比排放升高;在高转速工况,提高喷油压力能同时改善油耗和排放,而在低转速大负荷,呈现出与高转速工况相反的变化趋势, Soot和BSFC随着喷油压力提高同时上升;采用适当的主后喷间隔能达到改善排放的效果。试验结果表明, NOx加权排放为1.311 g/( kW·h),Soot加权排放为0.011 g/( kW·h),均满足国V排放标准,且加权油耗为211.6 g/( kW·h)。所优化的燃烧系统具有在降低对后处理系统要求的情况下满足国V排放标准的能力。
為瞭滿足今後更為苛刻的國V排放法規,本文在一檯無後處理滿足國Ⅳ排放的重型柴油機上進行瞭燃燒繫統優化試驗,結果錶明在大多數工況點,低壓級壓氣機有效流通麵積減小的兩級增壓方案2TC2與柴油機的聯閤運行點嚮著壓比和相似流量增大的方嚮移動,能明顯提高進氣壓力和空燃比,有效改善瞭氮氧化物( NOx)與燃油消耗率( BSFC)以及NOx與碳煙( Soot)的權衡( trade-off)關繫。通過優化設計燃燒室結構參數(縮口直徑、凹坑深度),縮口下移1 mm的燃燒室SF4能增彊缸內氣流運動,促進瞭燃油與空氣的混閤,實現瞭同時改善NOx-Soot和NOx-BSFC的trade-off關繫併維持缸內最大燃燒壓力至閤理水平。隨著主噴時刻的推遲,燃燒相位推遲,Soot比排放降低,但燃油經濟性變差,併且主噴時刻過多推遲會使Soot比排放升高;在高轉速工況,提高噴油壓力能同時改善油耗和排放,而在低轉速大負荷,呈現齣與高轉速工況相反的變化趨勢, Soot和BSFC隨著噴油壓力提高同時上升;採用適噹的主後噴間隔能達到改善排放的效果。試驗結果錶明, NOx加權排放為1.311 g/( kW·h),Soot加權排放為0.011 g/( kW·h),均滿足國V排放標準,且加權油耗為211.6 g/( kW·h)。所優化的燃燒繫統具有在降低對後處理繫統要求的情況下滿足國V排放標準的能力。
위료만족금후경위가각적국V배방법규,본문재일태무후처리만족국Ⅳ배방적중형시유궤상진행료연소계통우화시험,결과표명재대다수공황점,저압급압기궤유효류통면적감소적량급증압방안2TC2여시유궤적연합운행점향착압비화상사류량증대적방향이동,능명현제고진기압력화공연비,유효개선료담양화물( NOx)여연유소모솔( BSFC)이급NOx여탄연( Soot)적권형( trade-off)관계。통과우화설계연소실결구삼수(축구직경、요갱심도),축구하이1 mm적연소실SF4능증강항내기류운동,촉진료연유여공기적혼합,실현료동시개선NOx-Soot화NOx-BSFC적trade-off관계병유지항내최대연소압력지합리수평。수착주분시각적추지,연소상위추지,Soot비배방강저,단연유경제성변차,병차주분시각과다추지회사Soot비배방승고;재고전속공황,제고분유압력능동시개선유모화배방,이재저전속대부하,정현출여고전속공황상반적변화추세, Soot화BSFC수착분유압력제고동시상승;채용괄당적주후분간격능체도개선배방적효과。시험결과표명, NOx가권배방위1.311 g/( kW·h),Soot가권배방위0.011 g/( kW·h),균만족국V배방표준,차가권유모위211.6 g/( kW·h)。소우화적연소계통구유재강저대후처리계통요구적정황하만족국V배방표준적능력。
Optimization of a China Stage V diesel engine combustion system were carried out on a heavy-duty diesel engine, which has met the China Ⅳ emission standards under the condition of without the after-treatment device in order to meet the much more stringent emission regulations. Test results showed that, in most operation conditions, the joint operating point between diesel en-gine and the supercharger (2TC2) where the flow area of low pressure compressor is smaller, mov-ing in the direction of high pressure ratio and equivalent flow, can obviously increase intake pressure and air-fuel ratio, and effectively improve the trade-off relationships of NOx-Soot and NOx-BSFC (Brake Specific Fuel Combustion). Combustion chamber (SF4) where reentrant down 1 mm based on the original combustion chamber ( SF1 ) , can enhance airflow motion in cylinder, and increase the mixing uniformity and the mixing rate of fuel and gas. BSFC and Soot can be decreased and keep the maximum in-cylinder pressure in the reasonable range at the same time. With retarded injection timing, the combustion phase delay, Soot emissions decrease, and BSFC increase. The Soot emis-sions rise, however, when the injection timing delayed too much. Increasing the pressure of injec-tion can reduce Soot and BSFC simultaneously at the high speed conditions. However, Soot and BSFC is increase with the increasing of the injection pressure at low speed and high load conditions. By using proper interval between main and post, injection can improve emissions. The test results showed that NOx and Soot emission are 1. 799 g/( kW·h) and 0. 015 g/( kW·h) respectively, which both under the limit value of the China Stage V emission regulations. Meanwhile, BSFC can be reach 211. 6 g/( kW·h) . The optimized combustion chamber has the ability to meet the China Stage V emissions standard while reducing the requirement of exhaust after-treatment devices.