Analysis of the repeatability of the exhaust pollutants emission research results for cold and hot starts under controlled driving cycle conditions
Analysis of the repeatability of the exhaust pollutants emission research results for cold and hot starts under controlled driving cycle conditions
Artur Jaworski 0 1 2
Hubert Kuszewski 0 1 2
Adam Ustrzycki 0 1 2
Krzysztof Balawender 0 1 2
Kazimierz Lejda 0 1 2
Paweł Woś 0 1 2
0 Faculty of Mechanical Engineering and Aeronautics, Department of Combustion Engines and Transport, Rzeszow University of Technology , 8 Powstancow Warszawy Ave, 35-959 Rzeszow , Poland
1 Adam Ustrzycki
2 Artur Jaworski
Measurement of car engines exhaust pollutants emissions is very important because of their harmful effects on the environment. This article presents the assessment of repeatability of the passenger car engine exhaust pollutants emission research results obtained in the conditions of a chassis dynamometer. The research was conducted in a climate chamber, enabling the temperature conditions to be determined from − 20 to + 30 °C. The emission of CO, CH4, CO2, NOX, THC, and NMHC was subjected to the analysis. The aim of the research is to draw attention to the accuracy of the pollutant emission research results in driving cycles, and the comparison of pollutant emission results and their repeatability obtained in successive NEDC cycles under cold and hot start conditions. The results of the analysis show that, in the case of a small number of measurements, the results repeatability analysis is necessary for a proper interpretation of the pollutant emission results on the basis of the mean value. According to the authors' judgment, it is beneficial to determine the coefficient of variation for a more complete assessment of exhaust emission result repeatability obtained from a small number of measurements. This parameter is rarely presented by the authors of papers on exhaust components emission research.
Vehicle emissions; Exhaust measurements; Repeatability; Cold start test; Hot start test; Chassis dynamometer testing
Introduction
The harmful effects of transport on the environment are
mainly related to the emission of gaseous and particulate pollutants
Responsible editor: Philippe Garrigues
*
by internal combustion engines. For many years, work has
been conducted to minimize energy consumption and reduce
exhaust pollutants emissions. This also applies to the
introduced emission standards and testing procedures for internal
combustion engines. In the case of passenger cars and light
commercial vehicles, Euro procedures, which include
standards for exhaust pollutants emissions during driving cycles,
under controlled conditions, on a chassis dynamometer, and
road tests apply in the European Union
(European
Commission E 2007, 2015, 2017)
.
Limited reserves of crude oil, which is the primary raw
material for the production of gasoline and diesel, imply the
search for replacement fuels. Their introduction should not
result in an increase in exhaust pollutants emissions above
the limit levels specified in the standards.
The emissions researches conducted by different
laboratories show large differences in the values of the research results.
This is due to the very high number of factors that affect the
exhaust components emission levels
(Joumard et al. 2013)
.
Those are the factors related to the research equipment used,
the object of the research and their conditions. The main factor
on which the pollutant emissions level depends is the driving
cycle. Currently, new models of cars should go through
Cooling
fan
Chassis dyno
Control room with
Automation System
iGEM Vehicle
AMA
i60
i60 Bag
Cabinet
Silencer
CVS
i60
Blower
Weather Driver Climatic Chamber
station Aid
RMU
with
heater
legislative research in accordance with WLTP (World
Harmonized Light Vehicle Research Procedure), in which
WLTC cycles (World Harmonized Light Vehicles Test
Cycle) replace the NEDC test
(European Commission E
2017; Heinfellner et al. 2016)
. More emphasis is placed on
the tests that involve the cycles that are more closely related to
real-time driving cycles present on the roads
(Pielecha et al.
2016; Merkisz and Rymaniak 2017)
, reproduced on the
dynamometer bench, or the conduct of research organized on the
road (RDE—Real Driving Emissions). However, there are
divergent data on the emission levels differences derived from
NEDC and WLTC tests. According to papers
(Pelkmans and
Debal 2006; May et al. 2014)
, the emission of pollutants in
real traffic conditions is often higher than for NEDC. Also in
WLTP-compliant tests
(Marotta et al. 2015)
, higher emission
factors were reported for the entire test compared with NEDC
for CO and NOX in the case of gasoline engines, and for NOX
in the case of diesel engines. On the other hand, in paper
(Mast
2014)
, NOX emission in the case of a petrol engine was lower
for the entire WLTC test than for NEDC. Comparative tests of
the exhaust pollutants emissions for NEDC and WLTC tests
are also the object of numerous papers
(Andersson et al. 2014;
May et al. 2014; Bielaczyc et al. 2014, 2015; L (...truncated)