Cold Start Emission Characteristics of Heavy-Duty Diesel Engine under WHTC Cycle

LIAO Qingrui; WANG Fengbin; CHE Jintao; QIN Qingkong

doi:10.3969/j.issn.1001-2222.2024.02.003

Vehicle Engine ›› 2024, Vol. 0 ›› Issue (2) : 19. DOI: 10.3969/j.issn.1001-2222.2024.02.003

Cold Start Emission Characteristics of Heavy-Duty Diesel Engine under WHTC Cycle

LIAO Qingrui¹，WANG Fengbin^1,2，CHE Jintao¹，QIN Qingkong¹

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Abstract

Based on a diesel engine that meets the China Ⅵb emission standard, WHTC cycle emission testing was conducted on an engine bench equipped with a lowtemperature climatic chamber. Different simulated temperatures were set and the specific emission results of CO, HC, NO_x, PN, and PM were compared. Then the relationships of ambient temperature, intercooled temperature and exhaust temperature with exhaust pollutants were analyzed, and the differences in CO, HC, NO_x, and PN emission characteristics at different ambient temperatures during the three stages of WHTC cycle were also analyzed. The results showed that the specific emissions of NO_x, CO, and HC gradually increased, while the overall specific emissions of PN decreased, and the specific emissions of PM first decreased and then increased with the decrease of ambient temperature. The NO_x emissions under -10 ℃ and -15 ℃ in frozen urea state were 1.2 times and 3.3 times of those in unfrozen urea state. NO_x emission control mainly relied on DOC and EGR at stage 1 and stage 2 and was more dependent on SCR under the high torque and load conditions of stage 3. The differences caused by ambient temperatures in the CO and HC specific emission results mainly occurred in stage 1. At -15 ℃ and -20 ℃ conditions, the average concentration of PN in stage 1 to stage 3 was below 100 unit/cm³.

Key words

heavy-duty diesel engine / cold start / WHTC / emission measurement

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LIAO Qingrui，WANG Fengbin，CHE Jintao，QIN Qingkong. Cold Start Emission Characteristics of Heavy-Duty Diesel Engine under WHTC Cycle[J]. Vehicle Engine. 2024, 0(2): 19 https://doi.org/10.3969/j.issn.1001-2222.2024.02.003