Vehicle modal emissions measurement—techniques and issues

Hawley, J G; Bannister, Christopher D; Brace, Chris; Cox, A.; Ketcher, D. A.; Stark, R

doi:10.1243/0954407041581057

Cited by 17 publications

(10 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…where u i (−) is the ratio density of the pollutant i and the overall density of the exhaust, C i,tailpipe (ppm) is the measured concentration of the pollutant in the exhaust, and q mew (kg/s) is the exhaust mass flow rate measured (by PEMS) or estimated (by CVS). The CVS estimated exhaust flow rate was based on the CO 2 tracer method (i.e., by dividing the total CVS flow rate with the dilution ratio at the dilution tunnel) [14]. The dilution ratio was given by the ratio of the diluted and raw CO 2 measurements.…”

Section: Tailpipe Exhaust Massmentioning

confidence: 99%

See 1 more Smart Citation

Comparison of Portable Emissions Measurement Systems (PEMS) with Laboratory Grade Equipment

et al. 2018

View full text Add to dashboard Cite

Real-driving emissions (RDE) testing with portable emissions measurement systems (PEMS) during the type approval and in-service conformity of light-duty vehicles was recently introduced in the European Union legislation. In this paper, three PEMS were compared with laboratory analyzers connected to the tailpipe and the dilution tunnel. The tests were conducted with two Euro 6 vehicles (one gasoline and one diesel) performing the World harmonized Light vehicles Test Cycle (WLTC) and a pre-recorded RDE cycle on a chassis dynamometer. The results showed that the differences of the PEMS gas analyzers compared to the laboratory references were typically within 2% for CO2 and 5% for NOx. The CO2 and NOx mass emissions were within 10% and 15%, respectively, with only a few exceptions. The exhaust flow rate measurements were within 10% at low speeds (urban conditions), and 5% at higher speeds. These results confirm the legislated permitted tolerances and the 2017 PEMS uncertainty estimates.

show abstract

Section: Tailpipe Exhaust Massmentioning

confidence: 99%

“…The dilution ratio was given by the ratio of the diluted and raw CO 2 measurements. Some abnormal gas concentration spikes during the decelerations [14] were manually removed. All of the data was acquired at 1 Hz and the synchronization between the different equipment was also made to enable a comparison between them.…”

Section: Tailpipe Exhaust Massmentioning

confidence: 99%

Comparison of Portable Emissions Measurement Systems (PEMS) with Laboratory Grade Equipment

et al. 2018

View full text Add to dashboard Cite

show abstract

“…The tests employed six separate techniques for quantifying fuel consumption as described below and shown in Fig. 1: (a) bag analysis: an industry standard method which consists of performing a carbon balance on collected exhaust gases over the cycle (the measurement of fuel consumption using feedgas and tailpipe emissions were conducted while taking into account time alignment issues exposed in previous work by Hawley et al [7] and Bannister et al [8]); (b) feed gas carbon balance: similar to the bag test, only performed continuously on pre-catalyst gases;…”

Section: Experimental Set-upmentioning

confidence: 99%

Increasing accuracy and repeatability of fuel consumption measurement in chassis dynamometer testing

Brace

Burke

Moffa

2009

Proceedings of the Institution of Mechanical Engineers, Part D:

Self Cite

View full text Add to dashboard Cite

Made available with publisher permission. Always cite as follows: Brace, C. J., Burke, R., Moffa, J., 2009. Increasing accuracy and repeatability of fuel consumption measurement in chassis dynamometer testing.Abstract: The aim of this paper is to identify and investigate the effect of small changes in test conditions when quantifying fuel consumption. Twelve test set-up variables were identified and intentionally perturbed from a standard condition, including the effect of removing the power-assisted steering pump.Initially a design-of-experiments (DoE) approach was adopted and the results showed that most of the tested parameters had significant effects on fuel consumption. Most of these effects were greater than the effect of typical technology changes assessed on chassis dynamometer facilities. For example, an increase of 8.7 per cent in fuel consumption was observed following a 90 min battery discharge from vehicle headlamps. Similarly an increase of 5.5 per cent was observed when the rig was run 3 km/h faster over a drive cycle, and 2.6 per cent when using tyres deflated by 0.5 bar. As a consequence, statistical tolerancing was used to suggest typical tolerances for test rig set-up variables. For example it was recommended that the tyre pressure be controlled to within 0.1 bar and the test rig speed to 0.3 km/h. Further investigations were conducted into the effect of battery discharge, coast-down time, and engine cooling. These highlighted the need for rigorous battery charge management as the battery voltage was found not to be an appropriate measure of the variation in the alternator loading. Coast-down time was found to be a good control measure for a number of set-up variables affecting the rolling resistance of the vehicle. Finally the variations in the engine cooling were quantified using a cumulative engine temperature over a drive cycle. This was found to correlate well with fuel consumption. For each of these subsequent investigations, results were compared with the DoE predictions and found to agree well when considering the relatively low number of tests compared with the number of factors.

show abstract

“…This pollutant is common in Diesel engines, and particulate sizes range from 0.005 m to 30 m. The measurement of particulate matter is performed by reproducing real emission conditions in a Dilution Tunnel, where the exhaust gas emitted by the engine is diluted into the air before the sample is taken. Unlike for gaseous component analyzers Chan, 1996;Cui et al, 2004, Hawley et al, 2004, instantaneous particulate measurements cannot be performed with a Dilution Tunnel.…”

Section: Standard Pollutant Measurement Systemsmentioning

confidence: 99%

Measurement of hydrocarbon and carbon monoxide emissions during the starting of automotive DI Diesel engines

Broatch

Luján

Ruíz

et al. 2008

Int.J Automot. Technol.

View full text Add to dashboard Cite

Most of hydrocarbon (HC) and carbon monoxide (CO) emissions from automotive DI Diesel engines are produced during the engine warm-up period and are primarily caused by difficulties in obtaining stable and efficient combustion under these conditions. Furthermore, the contribution of engine starting to these emissions is not negligible; since this operating condition is highly unfavorable for the combustion progress. Additionally, the catalytic converter is ineffective due to the low engine temperature. In conjunction with adequate engine settings (fuel injection and fresh air control), either the glow plugs or the intake air heater are activated during a portion of the engine warm-up period, so that a nominal engine temperatures is reached faster, and the impact of these difficulties is minimized. Measurement of gaseous pollutants during engine warm-up is currently possible with detectors used in standard exhaust gas analyzers (EGA), which have response times well-suited for sampling at such transient conditions. However, these devices are not suitable for the measurement of exhaust emissions produced during extremely short time intervals, such as engine starting. Herein, we present a methodology for the measurement of the cumulative pollutant emissions during the starting phase of passenger car DI Diesel engines, with the goal of overcoming this limitation by taking advantage of standard detectors. In the proposed method, a warm canister is filled with an exhaust gas sample at constant volumetric flow, during a time period that depends on the engine starting time; the gas concentration in the canister is later evaluated with a standard EGA. When compared with direct pollutant measurements performed with a state-of-art EGA, the proposed procedure was found to be more sensitive to combustion changes and provided more reliable data.

show abstract

Vehicle modal emissions measurement—techniques and issues

Cited by 17 publications

References 3 publications

Comparison of Portable Emissions Measurement Systems (PEMS) with Laboratory Grade Equipment

Comparison of Portable Emissions Measurement Systems (PEMS) with Laboratory Grade Equipment

Increasing accuracy and repeatability of fuel consumption measurement in chassis dynamometer testing

Measurement of hydrocarbon and carbon monoxide emissions during the starting of automotive DI Diesel engines

Contact Info

Product

Resources

About