Heavy-Duty Engines-Conformity Testing based on PEMS - Lessons Learned from the European Pilot Program

The European emissions legislation requires to check the conformity of heavy-duty engines with the applicable emissions certification standards during the normal life of those engines: these are the “In Service Conformity” (ISC) requirements. It was considered impractical and expensive to adopt an in-service conformity (ISC) checking scheme for heavy-duty vehicles, which require removal of engines from vehicles to test pollutant emissions against legislative limits. Therefore, it has been proposed to develop a protocol for in-service conformity checking of heavy-duty vehicles based on the use of Portable Emission Measurement Systems (PEMS). The European Commission through DG ENTR in co-operation with DG JRC launched in January 2004 a co-operative research programme to study the feasibility of PEMS in view of their application in Europe for In-Service Conformity of heavy-duty engines. The technical and experimental activities were started in August 2004 to study the feasibility of PEMS systems and to study their potential application for on-road measurements on heavy-duty vehicles.The main objectives of the above project had been defined as follows: -To assess and validate the application and performance of portable instrumentation relative to each other, and in comparison with alternative options for ISC testing; -To define a test protocol for the use of portable instrumentation within the ISC of heavy-duty vehicles; -To assess on-road data evaluation methods such as the US ‘Not To Exceed’ (NTE) approach and possibly to develop a simplified ones; -To address the need of the European industry, authorities and test houses to go through a learning process with on-vehicle emissions testing. The main objective of the present document is to report on: a. The evaluation of the test protocol, i.e. to judge whether the mandatory data and its quality were appropriate for the final evaluation (S b. The analysis conducted to evaluate the potential of the different data evaluation (Pass/Fail) methods for ISC and in particular their ability to use on-road PEMS emissions data. The candidate methods were categorized into two families: -The "control-area / data reduction methods" (Chapter 4) that use only a part of the data, depending whether the operation points considered are part of a control area and belong to a sequence of consecutive points within this control area. The US-NTE (Not To Exceed) method - already established as an official tool in the United States - falls into this category but variations of the methods could be envisaged (with another control area for instance). -The "averaging window methods" (Chapter 4.3) that use all the operation data. The main objective of task b. was to answer the following question: “Once the data has been collected correctly, what is the most appropriate method to analyze the test data measured with PEMS and to judge whether the engine is in conformity with the applicable emissions limits?”JRC.F.9-Sustainable Transport (Ispra

NON ROAD ENGINES CONFORMITY TESTING BASED ON PEMS - Lessons Learned from the European Pilot Program

Since the EURO V standards for heavy-duty engines, the European emissions legislation requires to verify the conformity of heavy-duty engines with the applicable emissions certification standards: these provisions are identified as “In Service Conformity” (ISC). It was considered impractical and expensive to adopt an ISC scheme for heavy-duty vehicles requiring the removal of engines from vehicles to test pollutant emissions against legislative limits. Therefore, it was proposed to develop a protocol for in-service conformity checking of heavy-duty vehicles based on the use of Portable Emission Measurement Systems (PEMS). As a result, ISC testing based on PEMS was introduced in the EURO V and the EURO VI standards. The corresponding administrative and technical provisions were formulated in the European Regulations 582/2011 and 64/2012. The above route was followed for non-road engines as well: preliminary research activities studied and confirmed the possibility to apply the methods developed for heavy-duty engines with minor modifications. The basis for the introduction of ISC provisions based on the PEMS approach into the European NRMM type-approval legislation has been established in several texts. The NRMM PEMS Pilot Program was launched to facilitate the introduction into the European NRMM emissions legislation of use of PEMS as a tool for ISC. This had to be achieved by improving the technical procedures (e.g. available from the heavy-duty scheme) and increasing the awareness of the different stakeholders about PEMS as a new regulatory tool.JRC.F.8-Sustainable Transpor

Increasing the Neutralino Relic Abundance with Slepton Coannihilations: Consequences for Indirect Dark Matter Detection

We point out that if the lightest supersymmetric particle (LSP) is a Higgsino- or Wino-like neutralino, the net effect of coannihilations with sleptons is to increase the relic abundance, rather than producing the usual suppression, which takes place if the LSP is Bino-like. The reason for the enhancement lies in the effective thermally averaged cross section at freeze-out: sleptons annihilate (and co-annihilate) less efficiently than the neutralino(s)-chargino system, therefore slepton coannihilations effectively act as parasite degrees of freedom at freeze-out. Henceforth, the thermal relic abundance of LSP's corresponds to the cold Dark Matter abundance for smaller values of the LSP mass, and larger values of the neutralino pair annihilation cross section. In turn, at a given thermal neutralino relic abundance, this implies larger indirect detection rates, as a result of an increase in the fluxes of antimatter, gamma rays and neutrinos from the Sun orginating from neutralino pair annihilations.Comment: 16 pages, 6 figures, references added, typos corrected, matches with the published versio

Dark Matter in split extended supersymmetry

We consider the split extended (N=2) supersymmetry scenario recently proposed by Antoniadis et al. [hep-ph/0507192] as a realistic low energy framework arising from intersecting brane models. While all scalar superpartners and charged gauginos are naturally at a heavy scale, the model low energy spectrum contains a Higgsino-like chargino and a neutralino sector made out of two Higgsino and two Bino states. We show that the lightest neutralino is a viable dark matter candidate, finding regions in the parameter space where its thermal relic abundance matches the latest determination of the density of matter in the Universe by WMAP. We also discuss dark matter detection strategies within this model: we point out that current data on cosmic-ray antimatter already place significant constraints on the model, while direct detection is the most promising technique for the future. Analogies and differences with respect to the standard split SUSY scenario based on the MSSM are illustrated.Comment: 14 pages, references added, typos corrected, matches with the published versio

Electroweak baryogenesis, large Yukawas and dark matter

It has recently been shown that the electroweak baryogenesis mechanism is feasible in Standard Model extensions containing extra fermions with large Yukawa couplings. We show here that the lightest of these fermionic fields can naturally be a good candidate for cold dark matter. We find regions in the parameter space where the thermal relic abundance of this particle is compatible with the dark matter density of the Universe as determined by the WMAP experiment. We study direct and indirect dark matter detection for this model and compare with current experimental limits and prospects for upcoming experiments. We find, contrary to the standard lore, that indirect detection searches are more promising than direct ones, and they already exclude part of the parameter space

On-road Emissions of Light-duty Vehicles in Europe

Type approval is granted in the European Union to light-duty vehicles if these comply with emission limits during standardized emissions testing in the laboratory. Although applicable emission limits have become more stringent in past years, light-duty vehicles remain an important source of urban nitrogen oxides and carbon monoxide emissions. The persisting air quality problems suggest that standard emissions testing in the laboratory may not accurately capture the on-road emissions of light-duty vehicles. To address this hypothesis, we present the first comprehensive on-road emissions test of light-duty vehicles based on state-of-the-art Portable Emission Measurement Systems (PEMS). We find that nitrogen oxides emissions of gasoline vehicles as well as carbon monoxide and total hydrocarbon emissions of both diesel and gasoline vehicles generally stay below the respective emission limits. By contrast,However, Average nitrogen oxides emissions of diesel vehicles (0.93 ± 0.39 grams per kilometer [g/km]), including modern Euro 5 diesel vehicles (0.62 ± 0.19 g/km), exceed emission limits by 320 ± 90%. On-road carbon dioxide emissions surpass laboratory emission levels by 21 ± 9% and exceed the fleet-average emission target for passenger cars by 32 ± 20%. These findings suggest that the current emissions testing fails to accurately capture the on-road emissions of light-duty vehicles. Our research provides the empirical foundation for establishing a complementary emission test procedure for light-duty vehicles in Europe. This procedure that will be implemented together with more stringent Euro 6 emission limits in 2014. Both provisions should improve urban air quality and reinforce innovation and competitiveness of the automotive industry.JRC.F.9-Sustainable Transport (Ispra

In-Use Emissions Testing Developments in the New and Future European Motor Vehicle Emissions Regulations

In use emissions testing with Portable Emissions Measurement Systems (PEMS) has become one of the key elements of the European emissions legislation. The first ‘official’ step was the publication of the procedures to verify the conformity of gaseous emissions from heavy-duty engines, under the Commission Regulation (EU) 582/2011. To adapt these procedures to Non-Road Mobile Machinery (NRMM), a pilot program was launched and will address the specificities for testing and data evaluation. It will also stimulate the dissemination of know-how and the development of good practices. More recently, in-use emissions testing with PEMS became one of the solutions envisaged to control and limit the “real-driving emissions” of passenger cars, as foreseen in the EURO 6 Regulation 715/2007, which “requests the Commission to investigate the use of "portable emission measurement systems" (PEMS) and "not-to-exceed" regulatory concepts (...) and the need to bring real world emissions in line with those measured at type approval.” This paper will review the progress in the above-mentioned implementation of in-use emissions testing for regulatory purposes. It will describe the underlying principles used in Europe to check the conformity of large engines and those who might be at a later stage used to assess the real-driving emissions. Finally, the paper will discuss the role which in-use emissions testing may play in the upcoming regulatory efforts: proposing an effective and cost-efficient legislative scheme is becoming increasingly important as the diversity and the degree of sophistication of engine and vehicle technologies (e.g. hybrid and electric vehicles, alternative fuels) increases. In-use emissions testing may help to overcome some of the difficulties faced by the current standard emissions testing in the laboratory.JRC.F.8-Sustainable Transpor

Will Euro 6 reduce the NOx emissions of new diesel cars? - Insights from on-road tests with Portable Emissions Measurement Systems (PEMS)

The nitrogen dioxide (NO2) pollution in urban areas of Europe can be partially attributed to the increasing market penetration of diesel cars that show higher distance-specific nitrogen oxides (NOx) emissions than gasoline cars. The on-road NOx emissions of diesel cars, furthermore, appear to exceed substantially applicable emissions standards. This observation raises concerns that the introduction of more stringent Euro 6 emissions standards in 2014 may not adequately reduce the distance-specific on-road NOx emissions of new diesel cars. We address the existing concerns by analyzing the gaseous emissions of one novel Euro 6 diesel car and six Euro 4-5 diesel cars with Portable Emissions Measurement Systems (PEMS). We find that the average on-road NOx emissions of the Euro 6 car (0.21 ± 0.09 gram per kilometer [g/km]) are considerably lower than those of the Euro 4 cars (0.76 ± 0.12 g/km) and the Euro 5 cars (0.71 ± 0.30 g/km). The selective catalytic reduction (SCR) system of the Euro 6 diesel car is suitable to limit NOx emissions during real-world on-road driving. Still, all tested cars, including the Euro 6 diesel car, exceed their NOx emissions standards on the road by 260 ±130%. This finding suggests that the current type-approval procedure does not adequately capture the on-road NOx emissions of diesel cars. By introducing a complementary emissions test procedure that covers a wide range of normal operating conditions, the European legislative authorities can address this problem and ensure that Euro 6 will indeed deliver an adequate reduction in the NOx emissions of new diesel cars.JRC.F.8-Sustainable Transpor