How Well Can mPEMS Measure Gas Phase Motor Vehicle Exhaust Emissions?

Vu, Diep; Szente, Joseph J.; Loos, Michael; Maricq, M. Matti

doi:10.4271/2020-01-0369

Cited by 10 publications

(5 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They are also in agreement with our recent review that summarized tests from different laboratories [34]. Other researchers found ±8% CO differences for a gasoline vehicle and 15% on average for a 6.7 L diesel vehicle [35]. For NO x the differences were ±15% (absolute emission levels were not reported).…”

Section: Discussionsupporting

confidence: 92%

“…The measured variability of ±5 g/km translates into 3.5% for the 140 g/km CO 2 emission of this vehicle. Other researchers also found the agreement between PEMS and bags to be better than 5% [35,39]. This uncertainty is much lower than the 7.5-10% currently assumed for PEMS in the JRC assessment of the measurement uncertainty of PEMS [13,34].…”

Section: Discussionmentioning

confidence: 85%

See 1 more Smart Citation

Measurements of the Emissions of a “Golden” Vehicle at Seven Laboratories with Portable Emission Measurement Systems (PEMS)

et al. 2021

View full text Add to dashboard Cite

In the last years, the in-use emissions of vehicles are measured on the road with portable emissions measurement systems (PEMS). PEMS cannot measure as accurately as the laboratory grade equipment, and studies on their measurement uncertainty have continued since their appearance in the market. In this study we compared PEMS to laboratory grade equipment in Italian laboratories testing a diesel “Golden” (i.e., reference) vehicle for two consecutive years. The results showed equal means of PEMS and laboratory grade equipment for carbon dioxide (CO2), nitrogen oxides (NOx), and particle number (PN), with a variability of ±5 g/km for CO2, ±10 mg/km for NOx, and ±1 × 1011 p/km for PN, which further decreased in the second year. For carbon monoxide (CO), the PEMS were on average 5–20 mg/km higher than the bags (variability ±40 mg/km). The main conclusion of this study is that PEMS are accurate under controlled laboratory ambient conditions, without any indications of significant bias.

show abstract

Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 85%

Measurements of the Emissions of a “Golden” Vehicle at Seven Laboratories with Portable Emission Measurement Systems (PEMS)

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Even for the PEMS equipment (used for the homologation process), it is an accepted possibility to calculate the exhaust gas flow from fuel or intake airflow instead of with a direct read with a flowmeter. This is because the results obtained have similar accuracy to values from flowmeters or pitot tubes [58,74,75].…”

Section: Appendix C Nox Mass Emission Flow Estimationmentioning

confidence: 62%

A New Approach for Static NOx Measurement in PTI

et al. 2021

View full text Add to dashboard Cite

NOx emissions in vehicles are currently only controlled through the homologation process. There is a lack of knowledge to assess and control real NOx emissions of vehicles reliably. Even if vehicles in EU-27 are subject to Periodical Technical Inspection (PTI), NOx are not among the pollutants currently being controlled. For PTIs, tests need to be simple, quick, inexpensive, representative, and accurate. Ideally, tests need to be carried out under static conditions, without the need for a power bench or complex equipment. In this paper, a new approach for measuring NOx in PTI is proposed. The method has been developed and validated at a PTI Spanish station to ensure feasibility and repeatability. This method is based on the relationship between the “% engine load” value and exhaust NOx concentration at idle engine speed. Starting from the state of minimum possible power demand in a vehicle (idling and without any consumption), a load state with an average 98% increase in engine power demand is generated by connecting elements of the vehicle’s equipment. The relationship between power demand (through the “% engine load” value) and NOx concentration is then analyzed. The quality and representativity of this relationship have been checked with a p-value lower than 0.01. The method has been compared with a different NOx measurement technique, based on the simulation on a test bench and the ASM 2050 cycle, showing better performance in terms of repeatability and representativeness. The “% engine load” dispersion with the new approach is 7%, which ensures the reliability and repeatability of the method. The results show that the proposed method could be a valuable tool in PTI to detect high NOx emitting vehicles and to obtain information from the diesel vehicles fleet.

show abstract

“…It should be noted that using the ECU signals for exhaust mass flow estimation is accepted by European Union (EU) regulation 3 concerning the emission testing procedure for light-duty vehicles. Vu et al 2 report excellent correlations between exhaust flows estimation from ECU sensors and high accuracy SAO measurements, concluding that this is a viable method.…”

Section: Introductionmentioning

confidence: 99%

“…Both engine test bench and portable emissions measurement systems (PEMS) use CO 2 concentration analysers that are based on the non-dispersive infrared (NDIR) method. 2 Despite their high accuracy in steady state, they suffer from a slow time response (usually with a time constant between 2 and 5 s) and a delay that, depending on the length of the pipe connecting the exhaust with the analyser, can exceed 5–10 s.…”

Section: Introductionmentioning

confidence: 99%

Improving CO₂ emission assessment of diesel-based powertrains in dynamic driving cycles by data fusion techniques

Guardiola

Plá

Bares

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part D:

View full text Add to dashboard Cite

This article proposes a method based on the Kalman filter to improve the accuracy of the CO2 measurement in driving cycles such as worldwide harmonized light vehicles test cycles or real driving cycles which are inherently subject to a loss in accuracy due to the dynamic limitations of the CO2 analysers. The information from the analyser is combined with the electronic control unit estimation of the fuel injection. The characteristics of diesel engines and, in particular, the high efficiency of the combustion process and the diesel oxidation catalyst allows to compute the CO2 emissions from the fuel consumption estimation of the electronic control unit by applying the carbon balance method assuming negligible HC and CO emissions. Then, the assessment of the CO2 analyser response time and accuracy allows to pose an estimation problem that can be solved by a Kalman filter. The application of the method to different driving cycles shows that analyser dynamic limitations may lead to an overestimation of the CO2 figures that can reach 4% in highly dynamic tests such as the worldwide harmonized light vehicles test cycles. The technique thus has further potential application to replicating real driving cycles on the chassis dynamometer for real driving emission testing.

show abstract

How Well Can mPEMS Measure Gas Phase Motor Vehicle Exhaust Emissions?

Cited by 10 publications

References 25 publications

Measurements of the Emissions of a “Golden” Vehicle at Seven Laboratories with Portable Emission Measurement Systems (PEMS)

Measurements of the Emissions of a “Golden” Vehicle at Seven Laboratories with Portable Emission Measurement Systems (PEMS)

A New Approach for Static NOx Measurement in PTI

Improving CO₂ emission assessment of diesel-based powertrains in dynamic driving cycles by data fusion techniques

Contact Info

Product

Resources

About

How Well Can mPEMS Measure Gas Phase Motor Vehicle Exhaust Emissions?

Cited by 10 publications

References 25 publications

Measurements of the Emissions of a “Golden” Vehicle at Seven Laboratories with Portable Emission Measurement Systems (PEMS)

Measurements of the Emissions of a “Golden” Vehicle at Seven Laboratories with Portable Emission Measurement Systems (PEMS)

A New Approach for Static NOx Measurement in PTI

Improving CO2 emission assessment of diesel-based powertrains in dynamic driving cycles by data fusion techniques

Contact Info

Product

Resources

About

Improving CO₂ emission assessment of diesel-based powertrains in dynamic driving cycles by data fusion techniques