Assessment of a Euro VI Step E Heavy-Duty Vehicle’s Aftertreatment System

Giechaskiel, Barouch; Selleri, Tommaso; Gioria, Roberto; Melas, Anastasios; Franzetti, Jacopo; Ferrarese, Christian; Suarez-Bertoa, Ricardo

doi:10.3390/catal12101230

Cited by 6 publications

(5 citation statements)

References 57 publications

(95 reference statements)

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“…It is worth noticing that the NOx concentration at the tailpipe was not affected by this instantaneous change upstream during the low NOx phase, possibly due to the SCR unit operation. A similar behaviour was observed for other tested vehicles (e.g., vehicle #5, see Figure S1) and it has been also reported for a heavy-duty vehicle in the literature [28]. Thus, the observed pattern suggests that the proposed hot idling procedure in PTIs allows for the identification of a properly functioning SCR unit, without being affected by the EGR strategy.…”

Section: Hot Idling Testsupporting

confidence: 86%

“…Low NOx phase duration was determined from the hot idle start-up to the time when the tailpipe NOx concentration increased above 1 ppm. During the low NOx phase, the NOx reduction takes place due to their reaction with NH 3, which is available because the urea injection continues during vehicle hot idling or because it remains stored on the catalyst during the warm-up phase [20,27,28]. Both cases would suggest an SCR that is properly functioning, allowing a malfunctioning of the system to be excluded.…”

Section: Hot Idling Proceduresmentioning

confidence: 99%

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Assessment of a NOx Measurement Procedure for Periodic Technical Inspection (PTI) of Light-Duty Diesel Vehicles

et al. 2023

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A Periodic Technical Inspection (PTI) of vehicles promotes road safety and environmental protection. Indeed, a PTI is also used to verify the proper functioning of the vehicle’s aftertreatment system (ATS) over its lifetime. While the current Directive 2014/45/EU, which covers the PTI, does not require a NOx emissions measurement, the ongoing revision of the roadworthiness package aims at including new methods for measuring exhaust NOx and particle number (PN) emissions. PTI tests are required to be simple, quick, inexpensive and effective. In this study, a new methodology for a NOx measurement during the PTIs of Diesel vehicles equipped with a selective catalytic reduction (SCR) unit is assed. Seven Euro 6 light-duty Diesel vehicles fulfilling post-Real Driving Emissions (RDE) regulations were tested. The NOx-PTI methodology consists of measuring NOx emissions from the vehicle tailpipe at engine low idle speed after properly conditioning the vehicle ATS. In such conditions, a well-functioning SCR unit reduced NOx emissions and the methodology proved to be suitable to discriminate between functioning and malfunctioning SCR systems.

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Section: Hot Idling Testsupporting

confidence: 86%

Section: Hot Idling Proceduresmentioning

confidence: 99%

Assessment of a NOx Measurement Procedure for Periodic Technical Inspection (PTI) of Light-Duty Diesel Vehicles

et al. 2023

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“…At high concentrations, typically during cold starts or regenerations, the percentages are very low, indicating that the nature of the particles is different. Based on the literature, the particles during cold start at high concentrations have fuel combustion origins (i.e., soot), while those in the 10 11 #/kWh range during hot vehicle operation are formed by urea origins [23]. At the high-speed part of the cycle, high soot emissions due to passive regeneration can also be measured [17,[71][72][73].…”

Section: Vehicle Spn Emissionsmentioning

confidence: 99%

“…Urea dosing is used to reduce NO x emissions, but in some cases, "solid" particles appear downstream of the selective catalytic reduction for the NO x system [20]. Studies have found higher emissions of about +1 × 10 11 #/kWh by lowering the size from 23 nm to 10 nm [21][22][23]. These particles are believed to be ammonium salts [24,25] or urea decomposition products (cyanuric acid and ammelide) [21,[26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Solid Particle Number (SPN) Portable Emission Measurement Systems (PEMS) for Heavy-Duty Applications

Giechaskiel,

Melas,

Broekaert

et al. 2024

Applied Sciences

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A heavy-duty engine is homologated in a test cell. However, starting with Euro VI regulation, the in-service conformity is controlled with the engine installed in the vehicle using portable emission measurement systems (PEMS). In Europe, the application of solid particle number (SPN) PEMS started in 2021 for compression ignition (diesel) vehicles and in 2023 for positive ignition vehicles, thus including those operating with compressed natural gas (CNG). Even though today only particles with sizes > 23 nm are regulated, the Euro 7 proposal includes particles > 10 nm. There are not many studies on the accuracy of the SPN PEMS, especially for heavy-duty applications. In this study, PEMS measuring > 23 and >10 nm from two instrument manufacturers were compared with laboratory-grade instruments. The particle detector of one PEMS was a condensation particle counter (CPC), and of the other a the diffusion charger (DC). The results showed the robustness and good accuracy (40% or 1 × 1011 #/kWh) of the PEMS for ambient temperatures from −7 °C to 35 °C, active regeneration events, different fuels (Diesel B7, HVO, and CNG), different test cycles, cold start or hot engine operations, and high exhaust gas humidity content. Nevertheless, for the DC-based PEMS, sensitivity to pre-charged urea particles was identified, and for the CPC-based PEMS, sensitivity to pressure changes with one vehicle was nnoticed. Nevertheless, the results of this study confirm that the PEMS are accurate enough to measure even the stricter Euro 7 limits.

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“…12, x FOR PEER REVIEW 10 of 21and NO2 further increased. It is likely that urea injection was minimized or stopped at 2950 s, as the NOX conversion efficiency at such high temperatures is low due to thermodynamic limitations[94,95].…”

mentioning

confidence: 99%

Measurement of Light-Duty Vehicle Exhaust Emissions with Light Absorption Spectrometers

Giechaskiel,

Melas,

Franzetti

et al. 2024

Technologies

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Light-duty vehicle emission regulations worldwide set limits for the following gaseous pollutants: carbon monoxide (CO), nitric oxides (NOX), hydrocarbons (HCs), and/or non-methane hydrocarbons (NMHCs). Carbon dioxide (CO2) is indirectly limited by fleet CO2 or fuel consumption targets. Measurements are carried out at the dilution tunnel with “standard” laboratory-grade instruments following well-defined principles of operation: non-dispersive infrared (NDIR) analyzers for CO and CO2, flame ionization detectors (FIDs) for hydrocarbons, and chemiluminescence analyzers (CLAs) or non-dispersive ultraviolet detectors (NDUVs) for NOX. In the United States in 2012 and in China in 2020, with Stage 6, nitrous oxide (N2O) was also included. Brazil is phasing in NH3 in its regulation. Alternative instruments that can measure some or all these pollutants include Fourier transform infrared (FTIR)- and laser absorption spectroscopy (LAS)-based instruments. In the second category, quantum cascade laser (QCL) spectroscopy in the mid-infrared area or laser diode spectroscopy (LDS) in the near-infrared area, such as tunable diode laser absorption spectroscopy (TDLAS), are included. According to current regulations and technical specifications, NH3 is the only component that has to be measured at the tailpipe to avoid ammonia losses due to its hydrophilic properties and adsorption on the transfer lines. There are not many studies that have evaluated such instruments, in particular those for “non-regulated” worldwide pollutants. For this reason, we compared laboratory-grade “standard” analyzers with FTIR- and TDLAS-based instruments measuring NH3. One diesel and two gasoline vehicles at different ambient temperatures and with different test cycles produced emissions in a wide range. In general, the agreement among the instruments was very good (in most cases, within ±10%), confirming their suitability for the measurement of pollutants.

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Assessment of a Euro VI Step E Heavy-Duty Vehicle’s Aftertreatment System

Cited by 6 publications

References 57 publications

Assessment of a NOx Measurement Procedure for Periodic Technical Inspection (PTI) of Light-Duty Diesel Vehicles

Assessment of a NOx Measurement Procedure for Periodic Technical Inspection (PTI) of Light-Duty Diesel Vehicles

Solid Particle Number (SPN) Portable Emission Measurement Systems (PEMS) for Heavy-Duty Applications

Measurement of Light-Duty Vehicle Exhaust Emissions with Light Absorption Spectrometers

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