Comparative investigation of NOx emission characteristics from a Euro 6-compliant diesel passenger car over the NEDC and WLTC at various ambient temperatures

Jinyoung Ko, Dongyoung Jin, Wonwook Jang, Cha Lee Myung, Sangil Kwon, Simsoo Park

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

Euro 6-compliant diesel passenger cars have tended to feature lean NOx traps (LNTs) to satisfy the increasingly stringent NOx regulations. This paper focused on NOx emission characteristics by the NOx sensors installed at both before and after LNT from a Euro 6 diesel vehicle on a chassis dynamometer. The vehicle was repeatedly driven according to the new European driving cycle (NEDC) and the world-harmonized light-duty vehicle test cycle (WLTC) at various ambient temperatures (23, 14 and −5 °C). LNT regeneration was detected twice in the NEDC but 5 times in the WLTC due to the longer period, increased mileage and more frequent acceleration in the WLTC. Accordingly, the NOx conversion rate was higher, and the NOx emission factor was lower for the NEDC than for the WLTC. Additionally, as the ambient temperature decreased, the NOx concentration increased considerably. Because of the poor mixing of fuel and air and the reduced combustion efficiency and stability, the exhaust gas recirculation (EGR) rates decreased. Because the LNT did not reach the light-off temperature (LOT) in the cold start phase, the chemical reactions in the LNT did not occur, and only NO was detected. For the LNT regeneration process, the EGR rates decreased, and the fuel rates increased to release the stored NOx in the LNT. The emissions characteristics of the products, such as NO, NO2, N2O and NH3, during regeneration varied depending on the stored NOx, the after-treatment temperature, and the vehicle driving condition. The results from this comparative study can contribute to monitoring the NOx emission characteristics and optimizing the engine management system to meet future emission regulations including WLTC and low ambient temperature conditions.

Original languageEnglish
Pages (from-to)652-662
Number of pages11
JournalApplied Energy
Volume187
DOIs
Publication statusPublished - 2017 Feb 1

Fingerprint

Passenger cars
Exhaust gas recirculation
Temperature
Dynamometers
Chassis
Chemical reactions
Engines
Monitoring
Sensors
Air

Keywords

  • Ambient temperature
  • Lean NO trap (LNT)
  • New European driving cycle (NEDC)
  • NO emission
  • World-harmonized light-duty vehicle test cycle (WLTC)

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Energy(all)

Cite this

Comparative investigation of NOx emission characteristics from a Euro 6-compliant diesel passenger car over the NEDC and WLTC at various ambient temperatures. / Ko, Jinyoung; Jin, Dongyoung; Jang, Wonwook; Myung, Cha Lee; Kwon, Sangil; Park, Simsoo.

In: Applied Energy, Vol. 187, 01.02.2017, p. 652-662.

Research output: Contribution to journalArticle

@article{beb7c80b060a4bd9b1b7943e0e6a8d3a,
title = "Comparative investigation of NOx emission characteristics from a Euro 6-compliant diesel passenger car over the NEDC and WLTC at various ambient temperatures",
abstract = "Euro 6-compliant diesel passenger cars have tended to feature lean NOx traps (LNTs) to satisfy the increasingly stringent NOx regulations. This paper focused on NOx emission characteristics by the NOx sensors installed at both before and after LNT from a Euro 6 diesel vehicle on a chassis dynamometer. The vehicle was repeatedly driven according to the new European driving cycle (NEDC) and the world-harmonized light-duty vehicle test cycle (WLTC) at various ambient temperatures (23, 14 and −5 °C). LNT regeneration was detected twice in the NEDC but 5 times in the WLTC due to the longer period, increased mileage and more frequent acceleration in the WLTC. Accordingly, the NOx conversion rate was higher, and the NOx emission factor was lower for the NEDC than for the WLTC. Additionally, as the ambient temperature decreased, the NOx concentration increased considerably. Because of the poor mixing of fuel and air and the reduced combustion efficiency and stability, the exhaust gas recirculation (EGR) rates decreased. Because the LNT did not reach the light-off temperature (LOT) in the cold start phase, the chemical reactions in the LNT did not occur, and only NO was detected. For the LNT regeneration process, the EGR rates decreased, and the fuel rates increased to release the stored NOx in the LNT. The emissions characteristics of the products, such as NO, NO2, N2O and NH3, during regeneration varied depending on the stored NOx, the after-treatment temperature, and the vehicle driving condition. The results from this comparative study can contribute to monitoring the NOx emission characteristics and optimizing the engine management system to meet future emission regulations including WLTC and low ambient temperature conditions.",
keywords = "Ambient temperature, Lean NO trap (LNT), New European driving cycle (NEDC), NO emission, World-harmonized light-duty vehicle test cycle (WLTC)",
author = "Jinyoung Ko and Dongyoung Jin and Wonwook Jang and Myung, {Cha Lee} and Sangil Kwon and Simsoo Park",
year = "2017",
month = "2",
day = "1",
doi = "10.1016/j.apenergy.2016.11.105",
language = "English",
volume = "187",
pages = "652--662",
journal = "Applied Energy",
issn = "0306-2619",
publisher = "Elsevier BV",

}

TY - JOUR

T1 - Comparative investigation of NOx emission characteristics from a Euro 6-compliant diesel passenger car over the NEDC and WLTC at various ambient temperatures

AU - Ko, Jinyoung

AU - Jin, Dongyoung

AU - Jang, Wonwook

AU - Myung, Cha Lee

AU - Kwon, Sangil

AU - Park, Simsoo

PY - 2017/2/1

Y1 - 2017/2/1

N2 - Euro 6-compliant diesel passenger cars have tended to feature lean NOx traps (LNTs) to satisfy the increasingly stringent NOx regulations. This paper focused on NOx emission characteristics by the NOx sensors installed at both before and after LNT from a Euro 6 diesel vehicle on a chassis dynamometer. The vehicle was repeatedly driven according to the new European driving cycle (NEDC) and the world-harmonized light-duty vehicle test cycle (WLTC) at various ambient temperatures (23, 14 and −5 °C). LNT regeneration was detected twice in the NEDC but 5 times in the WLTC due to the longer period, increased mileage and more frequent acceleration in the WLTC. Accordingly, the NOx conversion rate was higher, and the NOx emission factor was lower for the NEDC than for the WLTC. Additionally, as the ambient temperature decreased, the NOx concentration increased considerably. Because of the poor mixing of fuel and air and the reduced combustion efficiency and stability, the exhaust gas recirculation (EGR) rates decreased. Because the LNT did not reach the light-off temperature (LOT) in the cold start phase, the chemical reactions in the LNT did not occur, and only NO was detected. For the LNT regeneration process, the EGR rates decreased, and the fuel rates increased to release the stored NOx in the LNT. The emissions characteristics of the products, such as NO, NO2, N2O and NH3, during regeneration varied depending on the stored NOx, the after-treatment temperature, and the vehicle driving condition. The results from this comparative study can contribute to monitoring the NOx emission characteristics and optimizing the engine management system to meet future emission regulations including WLTC and low ambient temperature conditions.

AB - Euro 6-compliant diesel passenger cars have tended to feature lean NOx traps (LNTs) to satisfy the increasingly stringent NOx regulations. This paper focused on NOx emission characteristics by the NOx sensors installed at both before and after LNT from a Euro 6 diesel vehicle on a chassis dynamometer. The vehicle was repeatedly driven according to the new European driving cycle (NEDC) and the world-harmonized light-duty vehicle test cycle (WLTC) at various ambient temperatures (23, 14 and −5 °C). LNT regeneration was detected twice in the NEDC but 5 times in the WLTC due to the longer period, increased mileage and more frequent acceleration in the WLTC. Accordingly, the NOx conversion rate was higher, and the NOx emission factor was lower for the NEDC than for the WLTC. Additionally, as the ambient temperature decreased, the NOx concentration increased considerably. Because of the poor mixing of fuel and air and the reduced combustion efficiency and stability, the exhaust gas recirculation (EGR) rates decreased. Because the LNT did not reach the light-off temperature (LOT) in the cold start phase, the chemical reactions in the LNT did not occur, and only NO was detected. For the LNT regeneration process, the EGR rates decreased, and the fuel rates increased to release the stored NOx in the LNT. The emissions characteristics of the products, such as NO, NO2, N2O and NH3, during regeneration varied depending on the stored NOx, the after-treatment temperature, and the vehicle driving condition. The results from this comparative study can contribute to monitoring the NOx emission characteristics and optimizing the engine management system to meet future emission regulations including WLTC and low ambient temperature conditions.

KW - Ambient temperature

KW - Lean NO trap (LNT)

KW - New European driving cycle (NEDC)

KW - NO emission

KW - World-harmonized light-duty vehicle test cycle (WLTC)

UR - http://www.scopus.com/inward/record.url?scp=85002990482&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85002990482&partnerID=8YFLogxK

U2 - 10.1016/j.apenergy.2016.11.105

DO - 10.1016/j.apenergy.2016.11.105

M3 - Article

AN - SCOPUS:85002990482

VL - 187

SP - 652

EP - 662

JO - Applied Energy

JF - Applied Energy

SN - 0306-2619

ER -