Effect of Injection Strategy on Low Load Premixed Combustion of a Diesel Engine in Engine Speed Extension

doi:10.16183/j.cnki.jsjtu.2021.433

Abstract

Abstract:

In this paper, the influence of the multiple injection strategy on premixed charge compression ignition (PCCI) combustion of a heavy-duty diesel engine in low load speed extension is studied experimentally and numerically, and the general optimization direction of low-load spray combustion of a heavy-duty diesel engine is obtained. The injection timing should match the shape of the combustion chamber, so that the oil, gas, and chamber are combined to make full use of the advantage of the shape of the combustion chamber. As the speed increases, the multi-injection strategy can overcome the defects such as the decrease of injection rate and the decrease of oil-gas mixing degree caused by the extension of injection duration. For single injection at a low speed, through optimizing the injection strategy, the NO_x emission is reduced by 38%, the soot emission is decreased by one order of magnitude, and the indicated thermal efficiency is increased by 8.66%. For single injection at a medium speed, the indicated thermal efficiency remains unchanged, the NO_x emission is reduced by 59.3%, and the soot emission is reduced by 70%. For single injection at a high speed, the thermal efficiency and the NO_x emission are increased slightly while the soot emission is decreased significantly. In addition, it is found that with the increase of speed, the influence of the multiple injection strategy on indicated thermal efficiency and emissions is gradually increased, and the optimization effect of the multiple injection strategy is more obvious than that of low speed.

Key words: internal combustion engine, speed extension, fuel injection strategy, premixed charge compression ignition (PCCI) combustion, emissions, indicated thermal efficiency

CLC Number:

TK422

FAN Chao, LU Yingying, LIU Yize. Effect of Injection Strategy on Low Load Premixed Combustion of a Diesel Engine in Engine Speed Extension[J]. Journal of Shanghai Jiao Tong University, 2023, 57(8): 1055-1066.

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参数	数值
缸径/mm	116
行程/mm	150
连杆长度/mm	224.5
涡流比	1.1
发动机转速/(r·min^-1)	1 000/1 400/1 800
喷油系统	高压共轨
喷油压力/MPa	160
喷孔数量	8
喷孔直径/mm	0.169
喷孔之间夹角/(°)	149
最大爆发压力/MPa	23
排量/L	9.5
压缩比	18.5
燃油种类	国V0号柴油

S/ (r·min^-1)	工况	R/%	φ_CA/(°) (P2SOI/D2/P1SOI/ D1/MSOI/D)	E/%
1 000	1	0	0/0/0/0/-30/4.1	43.19
	2	0	0/0/0/0/-25/4.1	45.24
	3	0	0/0/0/0/-15/4.1	51.99
	4	20	0/0/-30/0.6/-20/2.1	46.35
	5	30	0/0/-30/0.9/-20/1.8	45.19
	6	40	0/0/-30/1.1/-20/1.6	45.25
	7	50	0/0/-30/1.3/-20/1.3	45.96
	8	60	0/0/-30/1.6/-20/1.1	42.08
	9	70	0/0/-30/1.8/-20/0.9	52.00
1 400	1	0	0/0/0/0/-30/5.8	42.96
	2	0	0/0/0/0/-25/5.8	42.72
	3	0	0/0/0/0/-15/5.8	48.08
	4	20	0/0/-30/1/-20/3.6	44.47
	5	30	0/0/-30/1.5/-20/3.1	45.14
	6	40	0/0/-30/1.9/-20/2.7	44.83
	7	50	0/0/-30/2.3/-20/2.3	44.50
	8	60	0/0/-30/2.7/-20/1.9	44.68
	9	70	0/0/-30/3.1/-20/1.5	50.50

方案	R/%	φ_CA/(°) (P2SOI/D2/P1SOI/D1/MSOI/D)	N/[g·(kW·h)^-1]	C/[g·(kW·h)^-1]	E/%
基准工况	0	0/0/0/0/-15/4.1	5.92×10^-2	1.02×10^-4	51.99
对比工况1	60	0/0/-30/1.6/-20/1.1	6.65×10^-2	4.21×10^-4	32.92
对比工况2	40	0/0/-30/1.1/-20/1.6	7.87×10^-2	7.77×10^-4	39.02
优化方案1	0	0/0/0/0/-11/4.1	1.89×10^-2	2.21×10^-4	54.40
优化方案2	60	0/0/-21/1.6/-11/1.1	1.10×10^-1	4.99×10^-5	46.58
优化方案3	40	0/0/-20/1.1/-10/1.6	3.64×10^-2	1.13×10^-5	60.65
优化方案4	20+20	-20/0.6/-13/0.6/10/1.6	2.76×10^-2	2.73×10^-5	60.00

方案	R/%	φ_CA/(°) (P2SOI/D2/P1SOI/D1/MSOI/D)	N/[(g·(kW·h)^-1]	C/[g·(kW·h)^-1]	E/%
基准工况	0	0/0/0/0/-15/5.8	3.91×10^-2	2.09×10^-3	48.08
对比工况1	50	0/0/-30/2.3/-20/2.3	3.02×10^-2	2.21×10^-3	46.64
对比工况2	40	0/0/-30/1.9/-20/2.7	4.09×10^-2	2.20×10^-3	41.34
优化方案1	40	0/0/-25/1.9/-15/2.7	4.42×10^-2	8.24×10^-4	45.58
优化方案2	40	0/0/-20/1.9/-10/2.7	2.34×10^-2	8.69×10^-4	47.62
优化方案3	50	0/0/-20/2.3/-10/2.3	2.04×10^-2	3.44×10^-4	47.77
优化方案4	25+25	-20/0.6/-12/0.6/-10/2.7	1.59×10^-2	6.18×10^-4	48.41

方案	R/%	φ_CA/(°) (P2SOI/D2/P1SOI/D1/MSOI/D)	N/[g·(kW·h)^-1]	C/[g·(kW·h)^-1]	E/%
1	0	0/0/0/0/-30/7.4	2.18×10^-2	2.06×10^-3	42.14
2	0	0/0/0/0/-25/7.4	2.02×10^-2	3.68×10^-3	42.62
3	0	0/0/0/0/-15/7.4	1.06×10^-2	1.01×10^-2	47.98
4	40	0/0/-30/3/-20/4.6	1.97×10^-2	6.7×10^-3	48.84
5	50	0/0/-30/3.7/-20/3.9	1.99×10^-2	7.09×10^-3	48.61
6	40	0/0/-25/3/-15/4.6	1.64×10^-2	3.37×10^-3	49.55
7	50	0/0/-25/3.7/-15/3.9	1.88×10^-2	3.08×10^-3	49.83
8	20+20	-25/1.9/-18/1.9/-15/3.9	1.32×10^-2	3.27×10^-3	48.88
9	25+25	-25/1.9/-18/1.9/-15/3.9	1.34×10^-2	5.67×10^-3	48.70