Characteristics of NOX and NH3 emissions from in-use heavy-duty diesel vehicles with various aftertreatment technologies in China

Liqiang He; Gang Li; Xiaomeng Wu; Shaojun Zhang; Miao Tian; Zhenhua Li; Cheng Huang; Qingyao Hu; Ye Wu; Jiming Hao

doi:10.1016/j.jhazmat.2023.133073

Characteristics of NO_X and NH₃ emissions from in-use heavy-duty diesel vehicles with various aftertreatment technologies in China

J Hazard Mater. 2024 Mar 5:465:133073. doi: 10.1016/j.jhazmat.2023.133073. Epub 2023 Nov 25.

Authors

Liqiang He¹, Gang Li², Xiaomeng Wu³, Shaojun Zhang⁴, Miao Tian², Zhenhua Li⁵, Cheng Huang⁶, Qingyao Hu⁶, Ye Wu⁴, Jiming Hao⁴

Affiliations

¹ State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China.
² State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
³ School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China. Electronic address: wuxmeng@tsinghua.edu.cn.
⁴ School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China; State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China.
⁵ School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China.
⁶ State Environmental Protection Key Laboratory of Cause and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, China.

PMID: 38039816
DOI: 10.1016/j.jhazmat.2023.133073

Abstract

Some in-use China IV and China V heavy-duty diesel vehicles (HDDVs) with selective catalytic reduction (SCR) systems probably fail to mitigate nitrogen oxide (NO_X) emissions as expected. Meanwhile, these SCR-equipped HDDVs might emit excessive ammonia (NH₃). To better understand the NO_X and NH₃ emissions from typical HDDVs in China, seventeen in-use vehicles with various emission-control technologies were tested by using laboratory chassis dynamometers. The results indicated that individual NO_X and NH₃ emissions from HDDV fleets widely varied owing to differences in aftertreatment performance. China V and VI HDDVs with effectively functioning SCRs could substantially control their NO_X emissions to be below the corresponding emission limits (i.e., 4.0 and 0.69 g/kWh for China V and China VI vehicles, respectively) but with a potential risk of high NH₃ emissions caused by diesel exhaust fluid (DEF) overdosing. Furthermore, higher vehicle speed and payload resulted in lower NO_X emissions and possibly higher NH₃ emissions from HDDVs with effectively functioning SCRs, while higher NO_X emissions from tampered- and non-SCR HDDVs. NO_X emissions from China VI HDDVs were more sensitive to cold starts compared to China V and earlier vehicles, but there was no significant discrepancy in NH₃ emissions between cold- and hot-start tests.

Keywords: Ammonia (NH(3)); Driving conditions; Heavy-duty diesel vehicles; Nitrogen oxide (NO(X)); Selective catalytic reduction (SCR).