TY - JOUR
T1 - Evaluation of the real-time de-NOx performance characteristics of a LNT-equipped Euro-6 diesel passenger car with various vehicle emissions certification cycles
AU - Myung, Cha Lee
AU - Jang, Wonwook
AU - Kwon, Sangil
AU - Ko, Jinyoung
AU - Jin, Dongyoung
AU - Park, Simsoo
N1 - Funding Information:
This research was supported by the BK21 plus program (21A20131712520) through the National Research Foundation (NRF) funded by the Ministry of Education of Korea and the Korea University Grant. The authors gratefully acknowledge the National Institute of Environmental Research (NIER) for the laboratory tests. We also thank Hyundai Motor Company's technical assistance for evaluation of LNT equipped Euro-6 diesel vehicle.
PY - 2017
Y1 - 2017
N2 - Advanced nitrogen oxides (NOx) after-treatment systems for diesel cars are effectively reducing tailpipe NOx emissions in laboratory test cycles; however, some de-NOx systems showed limitation for passing environmental standards during real-world driving conditions. In this study, the NOx concentration of a lean NOx trap (LNT)-equipped diesel engine were investigated over various vehicle certification cycles. The LNT performance was compared to the new European driving cycle (NEDC), world-harmonized light-duty vehicle test cycle (WLTC), federal test procedure (FTP)-75, highway fuel economy test (HWFET), and US06. The real-time NOx concentration behaviors were tracked using NOx sensors at the engine-out and downstream of the LNT to determine the NOx storage and regeneration phase. The NOx conversion efficiencies were 36.3–71.7% of which reflecting the mode severity and cycle duration of the diesel engine. The tailpipe NOx emissions were 0.059 g/km during the NEDC which was within the Euro-6 emissions regulations. The NOx emissions in the WLTC, FTP-75, and US06 modes were approximately 1.9, 1.5, and 6.6 times higher than the NEDC due to the higher frequency of LNT purge and higher engine-out NOx formation. During the diesel particulate filter (DPF) regenerating stage in WLTC mode, tailpipe NOx emissions substantially increased by more than 8.8-fold. The exhaust gas recirculation (EGR) supply and lambda control scheme were closely related with strong NOx increment at de-NOx and de-PM processes.
AB - Advanced nitrogen oxides (NOx) after-treatment systems for diesel cars are effectively reducing tailpipe NOx emissions in laboratory test cycles; however, some de-NOx systems showed limitation for passing environmental standards during real-world driving conditions. In this study, the NOx concentration of a lean NOx trap (LNT)-equipped diesel engine were investigated over various vehicle certification cycles. The LNT performance was compared to the new European driving cycle (NEDC), world-harmonized light-duty vehicle test cycle (WLTC), federal test procedure (FTP)-75, highway fuel economy test (HWFET), and US06. The real-time NOx concentration behaviors were tracked using NOx sensors at the engine-out and downstream of the LNT to determine the NOx storage and regeneration phase. The NOx conversion efficiencies were 36.3–71.7% of which reflecting the mode severity and cycle duration of the diesel engine. The tailpipe NOx emissions were 0.059 g/km during the NEDC which was within the Euro-6 emissions regulations. The NOx emissions in the WLTC, FTP-75, and US06 modes were approximately 1.9, 1.5, and 6.6 times higher than the NEDC due to the higher frequency of LNT purge and higher engine-out NOx formation. During the diesel particulate filter (DPF) regenerating stage in WLTC mode, tailpipe NOx emissions substantially increased by more than 8.8-fold. The exhaust gas recirculation (EGR) supply and lambda control scheme were closely related with strong NOx increment at de-NOx and de-PM processes.
KW - Conversion efficiency
KW - Diesel NO emissions
KW - Lean NO trap
KW - Regeneration
KW - Vehicle test modes
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U2 - 10.1016/j.energy.2017.05.089
DO - 10.1016/j.energy.2017.05.089
M3 - Article
AN - SCOPUS:85019945043
VL - 132
SP - 356
EP - 369
JO - Energy
JF - Energy
SN - 0360-5442
ER -