WorldCat Identities

Clairotte, Michael

Works: 8 works in 11 publications in 1 language and 10 library holdings
Publication Timeline
Most widely held works by Michael Clairotte
Characterisation of real-world CO2 variability and implications for future policy instruments( )

2 editions published in 2017 in English and held by 2 WorldCat member libraries worldwide

There is increasing evidence suggesting that real-world fuel consumption and CO2 emissions improvements in the last decade have been much lower than the officially reported ones. Scientific studies show that the offset between officially reported values and real-world vehicle CO2 emissions in Europe has constantly increased over the last years. The difference between officially reported and actual CO2 emissions of vehicles has three main implications: a) it undermines the collective effort to reduce greenhouse gas emissions in Europe, b) it creates an unfair playing field for different competitors, and c) it affects the credibility of vehicle manufacturers. As a fundamental step to deal with this issue the European Commission has replaced the old and outdated NEDC test procedure used so far in the emission type-approval of vehicles by the Worldwide harmonized Light vehicles Test Procedure (WLTP). Being a lab-based test-procedure, the WLTP, by its nature, can only cover part of the CO2 gap. Some stakeholders have suggested that the remaining gap could be tackled by additional measures based on real-world measurements. The objective of the present report is to analyse possible ways to deal with the remaining CO2/fuel consumption gap. In particular, fleet-wide monitoring of real-world fuel consumption and model-based tools able to provide customized information to road users are the measures suggested. In addition, the paper presents experimental evidence on the variability of the CO2/fuel consumption of vehicles, putting into question the idea that a single central estimate of these quantities may be sufficient
Impact of fuels and exhaust aftertreatment systems on the unregulated emissions from mopeds, light and heavy‐duty vehicles( Book )

1 edition published in 2014 in English and held by 2 WorldCat member libraries worldwide

Transport sector plays a key role in climate change and air pollution. Among the anthropogenic sectors, on-road transport is recognized as the first contributor to global warming, mainly due to its emission of carbon dioxide, ozone precursors and carbonaceous aerosols. In addition, on-road transport contributes to the deterioration of air quality by releasing nitrogen oxides, hydrocarbons, carbonyls, ammonia, and aerosols. However, the current European legislation of vehicles emissions focusses on a limited number of pollutants, namely hydrocarbons, carbon monoxide, nitrogen oxides, and particulate matter. The aim of this work was to improve the knowledge about the emission factors of gas phase and particle-associated emissions from vehicle exhaust. The impacts of aftertreatment devices and fuel quality on regulated and unregulated species were studied. Several sampling campaigns with different types of vehicles were conducted in the vehicle emission laboratory (VELA) at the European Commission Joint Research Centre (EC-JRC) Ispra, Italy. The vehicles chosen were representative of some categories circulating in Europe (heavy duty vehicles, light duty vehicles, two-stroke mopeds), and either standard fuel or some alternative fuels (ethanol and liquefied petroleum gas) were used. The gas phase was monitored by a Fourier transform infrared spectrometer (carbonyls, nitrogen-containing species, small hydrocarbons), and a resonance-enhanced multiphoton ionization time-of-flight mass spectrometer (mono and polycyclic aromatic hydrocarbons). The particulate phase was analyzed by a high-resolution time-of-flight aerosol mass spectrometer (organic aerosol, chloride, nitrate), and a multiangle absorption photometer (black carbon). The mopeds were found to have the higher emission factors of primary organic aerosol and polycyclic aromatic hydrocarbons. While efficient to reduce the regulated emissions, the aftertreatment used to comply with the moped Euro 2 emission standard might be responsible of large emission of unregulated organic aerosols. Most of the emission linked to the gasoline light duty vehicles were released before the light-off of the catalyst. Whereas alternative fuels studied helped to reduce ozone precursor emissions, the pollutants associated to the cold start of the vehicle reduced this beneficial effect. Finally, the heavy duty diesel vehicles featured the highest nitrogen oxides and black carbon emissions. Despite efficient retrofit and aftertreatment systems (for particles and nitrogen oxides), these vehicles could release significant amount of ammonia. These results provided valuable insights for the drafting of legislation related to the achievement of sustainable transport in Europe
Preparatory work for the environmental effect study on the Euro 5 step of L-category vehicles( )

2 editions published in 2016 in English and held by 1 WorldCat member library worldwide

The European Union Regulation 168/2013 [1] requires an Effect Study to confirm the provisions (defined thereby and in Regulation 134/2014 [2]) for the type approval of the Euro 5 L-category vehicles (two- or three-wheel vehicles and quadricycles, such as quads and minicars). The present report describes the testing methodology and preliminary results as input to the main Effect Study. Upon request of DG-GROWTH (Directorate General for Internal Market, Industry, Entrepreneurship and SMEs), the European Commission Joint Research Centre (JRC) undertook an experimental campaign on 12 L-category vehicles to test their propulsion unit and environmental performance in line with a new paradigm: In principle, a vehicle should be clean and energy efficient in each and every operation point. In particular, vehicles belonging to the L-category family were tested over the current legislative test procedure, according to the future legislation contained in Regulation 168/2013 [1] and during a wide open throttle test to assess the maximum performance of the vehicles (max power and torque). Several engine load variables were logged during the experimental testing: Second-by-second mass emissions of carbon dioxide, fuel consumption, power and torque at the wheel, throttle position, etc. The use of load variables is especially useful when on-road driving has to be compared to the legislative testing conditions. The new test cycle proposed for Euro 5 type approval, the Worldwide harmonized Motorcycle Test Cycle (WMTC) proved to be better than the present driving cycle in terms of quantity, quality and dynamics of testing/sampling points. The results related to the monitored load variables are vehicle specific and it was not possible to identify a single all-purpose fitting variable capable of describing engine load conditions during the test. Nevertheless the set of variables investigated in this work are promising and will be used as underpinnings for the Effect Study
Including cold-start emissions in the Real-Driving Emissions (RDE) test procedure an assessment of cold-start frequencies and emission effects( Book )

1 edition published in 2017 in English and held by 1 WorldCat member library worldwide

We document two independent analyses that were conducted to support the inclusion of cold-start emissions in the Real-Driving Emissions (RDE) test procedure. First, we present the results of a scoping review on cold-start frequencies and trip distances in Europe. Second, we present a scenario analysis that aims to quantify the impact of modifications in the RDE data pre-processing and evaluation on the calculated NOX emissions over the urban part of an on-road test. We find that some 27 ± 5% of trips in Europe may contain a cold start. The driving distance between two consecutive cold starts reaches 36 ± 16 km (mean) and 30 ± 13 km (median), respectively. Our scenario analysis suggests that a simple inclusion of cold start into the regulatory RDE data evaluation procedure may not capture cold-start NOX emissions in a robust manner. However, combining modifications of the RDE data pre-processing and the RDE data evaluation can capture at least part of the incremental cold-start NOX emissions. A more systematic assessment of European driving data and an expansion of the scenario analysis presented here could substantiate the findings of this report
On-road vehicle emissions beyond RDE conditions : experimental assessment addressing EU Real-Driving Emission (RDE)( )

1 edition published in 2019 in English and held by 1 WorldCat member library worldwide

Passenger cars are an important source of air pollution, especially in urban areas. Recently, real-driving emissions (RDE) test procedures have been introduced in the EU aiming to evaluate nitrogen oxides (NOx) and particulate number (PN) emissions from passenger cars during on-road operation. Although RDE accounts for a large share of real-world driving, it excludes certain driving situations by setting boundary conditions (e.g., in relation to altitude, temperature or dynamic driving). The present work investigates the on-road emissions of NOx, NO2, CO, particle number (PN) and CO2 from a fleet of twenty-one Euro 6b, 6c and 6d-TEMP vehicles, including diesel, gasoline (GDI and PFI) and compressed natural gas (CNG) vehicles. The vehicles were tested under different on-road driving conditions both inside and outside of RDE boundaries. These included 'baseline' tests within RDE conditions, but also testing in conditions beyond the RDE boundary conditions to investigate the performance of the emissions control devices in demanding situations. Consistently, low average emission rates of PN and CO were measured from all diesel vehicles tested under most conditions. Moreover, the tested Euro 6d-TEMP and Euro 6c diesel vehicles met the NOx emission limits applicable to Euro 6d-TEMP diesel vehicles during RDE tests (168 mg/km). Some of the vehicle met this limits even outside the RDE boundaries. The Euro 6b GDI vehicle equipped with a gasoline particulate filter (GPF) presented PN emissions < 6×1011 #/km. These results, in contrast with previous on-road measurements from earlier Euro 6 vehicles, indicate more efficient emission control technologies are currently being used in diesel and gasoline vehicles. However, the results described in this report also raise some new concerns. In particular, the emissions of CO (measured during the regulated RDE test, but without an emission limit associated to it) or PN from PFI vehicles (presently not covered by the Euro 6 standard) showed elevated results in some occasions. Emissions of CO were up to 7.5 times higher when the more dynamic tests were conducted and the highest PN emissions were measured from a PFI gasoline vehicle during dynamic driving. The work also investigates how NOx, CO, PN and CO2 on-road emissions from three vehicles are impacted by sub-zero ambient temperatures and high altitudes. Two of the tested vehicles were Euro 6d-TEMP certified vehicles, one diesel and one gasoline, and one was a Euro 6b plug-in hybrid vehicle. The vehicles were studied during tests that do not fulfil the boundary conditions in terms of maximum altitude, altitude gain, and/or minimum temperature. The obtained emissions were compared to those obtained during tests performed along RDE routes. The results indicate that cold ambient temperature and high altitude, outside the RDE boundary conditions, lead to in higher NOx, CO and PN emissions compared to moderate conditions of temperature and altitude. Nonetheless, the two Euro 6d-TEMP vehicles tested in those extreme conditions yielded NOx emissions factors that fulfilled the Euro 6d-TEMP emission requirements. Our work underlines the importance of a technology- and fuel-neutral approach to vehicle emission standards, whereby all vehicles must comply with the same emission limits for all pollutants
Intercomparison of ethanol, formaldehyde and acetaldehyde measurements from a flex-fuel vehicle exhaust during the WLTC( )

1 edition published in 2017 in English and held by 1 WorldCat member library worldwide

Highlights: Ethanol, formaldehyde and acetaldehyde measurements were performed during the WLTC. Measurements from all the instruments were in good agreement. Non-methane organic gases resulted to be higher than non-methane hydrocarbons. Abstract: An intercomparison exercise of the world-harmonized light-duty vehicle test procedure (WLTP) aiming at measuring ethanol, formaldehyde and acetaldehyde emissions from a flex-fuel light-duty vehicle using E85 was conducted in the Vehicle Emission Laboratory (VELA) at the European Commission Joint Research Centre (EC-JRC), Ispra, Italy. The instruments used during the intercomparison allowed online measurements of these compounds directly from the diluted exhaust. Measurements were done either in real time or immediately after the test. The measurement and analysis of exhaust emissions over the world-harmonized light-duty vehicle test cycle was done by means of Fourier transform infrared spectroscopy (FTIR), proton transfer reaction-mass spectrometry (PTR-Qi-ToF-MS), photoacoustic spectroscopy (PAS) and gas chromatography (GC). Results showed that online systems can perform measurements from the vehicle diluted exhaust assuring a good repeatability (within instrument variance) and reproducibility (between instrument variance) of the results. Measurements from all the instruments were in good agreement (|Z-score| <2). Results showed that online systems can perform measurements from the vehicle diluted exhaust assuring the reproducibility and repeatability of the results. Results obtained measuring at the tailpipe using a FTIR were in good agreement with those acquired measuring at the constant volume sampler (CVS). Considering the low sensitivity of the current technique used to measure hydrocarbons emissions towards oxygenated compounds (flame ionization detector; FID), non-methane organic gases (NMOG) were calculated applying their FID response factors to the measured emissions of ethanol, acetaldehyde and formaldehyde. NMOG resulted to be up to 74% higher than measured non-methane hydrocarbons (NMHC)
Real Driving Emissions (RDE) : 2020 assessment of Portable Emissions Measurement Systems (PEMS) measurement uncertainty( )

1 edition published in 2021 in English and held by 1 WorldCat member library worldwide

This report describes the 2020 assessment of the margins for the RDE (Real-Driving Emissions) results prescribed in the EURO 6 regulation. Margin is defined as the additional measurement uncertainty introduced by PEMS (Portable Emissions Measurement Systems) compared to the laboratory systems for a pollutant. The 2020 data collected by a series of EU testing houses showed in general very good performance of the PEMS in terms of NOx zero drift and laboratory validation results. In consequence, the framework to calculate the NOx margin was modified and together with the observed improvement of the exhaust flow meter's uncertainty, the NOx margin may now be decreased from 0.32 to 0.23. In practical terms, this value covers at least 95% of the worst cases, compared to the 99% of the previous report. The data suggest that further reduction is possible by improving the permissible tolerances for the equipment in the regulation and the method by which the zero drift is taken into account. Under this future scenario the future NOx margin could be reduced to 0.10, but this requires first changes in the regulation. In this report, the framework was further developed to analyse the Particle Number (PN) margin. Based on the analysis of this report the PN margin is now estimated to be 34% (0.34). For further reductions of the PN margin a more holistic approach is necessary (e.g. bringing closer technical and calibration specifications of the PN-PEMS and the reference PMP systems)
Phase 1 of the environmental effect study on the Euro 5 step of L-category vehicles : stocktaking and data mining( )

2 editions published in 2016 in English and held by 1 WorldCat member library worldwide

The European Union Regulation 168/2013 [1] requires an environmental effect study to confirm the provisions (defined therein and in Regulation 134/2014 [2]) for the type approval of the Euro 5 L-category vehicles (two- or three-wheel vehicles and quadricycles, such as quads and minicars). This effect study aims at providing additional information using modelling, technical feasibility and cost-effectiveness analysis based on the latest available data. Upon request of DG-GROW (Directorate General for Internal Market, Industry, Entrepreneurship and SMEs), the European Commission Joint Research Centre (JRC) undertook a pre-study [3] and the phase 1 of the effect study. The phase 1 includes the stocktaking of L-category vehicles and data mining of their type I test values (tailpipe emissions after a cold-start, prescribed driving cycle), which are presented in the present report.^From the stocktaking collected, it was found that very scarce data related to other L-categories than two-wheel moped (L1e) and motorcycle (L3e) are currently available. In addition, data originating from different sources (e.g., manufacturers and EUROSTAT) displayed noticeable differences in terms of vehicle stock (up to 8%) and new registration, in particular for L1e category. A source of harmonized stocktaking data are required to ensure reliable model projections, and guarantee unbiased cost-benefit analysis. From the datamining on type I test values from L-category vehicles, the overview was achieved for actual L1e, L3e, powered tricycle (L5e) and heavy quadricycle (L7e) based on data collected from the German Federal Motor Transport Authority (KBA). It was found that L1e was the category displaying the highest share of models with type I test values lower than Euro 4 emission limits, followed by the L3e and the L5e categories (63%, 8%, and 7% respectively).^In addition, the L3e and the L5e categories presented models already complying with Euro 5 standards. Finally, the L7e category displayed models complying neither with Euro 4, nor Euro 5 standards. Therefore, among the L-categories studied in this report, L7e may have to undertake a significant effort to comply with the foreseen Euro 4 and Euro 5 standard
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