Diesel Trap Performance: Particle Size Measurements and Trends

Abdul-Khalek, Imad S.; Kittelson, David B.; Brear, Fred

doi:10.4271/982599

Cited by 74 publications

(41 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As several studies in the past have experimentally identified (e.g. Abdul-Khalek et al, 1998;Mathis et al, 2004b), the number and mass concentration of particles in the NM largely depend on the dilution ratio. It is therefore important to study whether these experimental results can be explained by modeling.…”

Section: Effect Of Aging Time On Particlesmentioning

confidence: 99%

See 1 more Smart Citation

Theoretical Investigation of the Nucleation Mode Formation Downstream of Diesel After-treatment Devices

Vouitsis

Ntziachristos

Samaras

2008

Aerosol Air Qual. Res.

View full text Add to dashboard Cite

This study presents a modeling approach to the formation and growth of nucleation mode particles when sampling aerosol from the exhaust of a diesel engine. The simulation assumes primary particle formation due to sulphuric acid nucleation and subsequent particle growth as hydrocarbons condense on the primary nuclei. The modeling results are validated against experimental data of particle number concentrations at various dilution ratios and aging times after raw exhaust sampling. In addition, exhaust aerosol of different characteristics is produced by fitting in the engine exhaust line a diesel oxidation catalyst, a diesel particle filter, and a combination of the two. The model is able to satisfactorily reproduce the particle number and mass concentrations of exhaust particles in the nucleation mode for a variety of sampling and after-treatment conditions, with a small delay (50-200 ms) in the initiation of nucleation compared to the experiments. The measured and simulated particle concentrations are in the same order of magnitude with the exact simulated values, depending on the fuel-sulphur conversion rate and the profile of organics considered in the exhaust. This study indicates that a detailed chemical analysis of the exhaust gas, including organic speciation and sulphuric acid concentration, combined with an aerosol dynamics model, would result in a satisfactory prediction of the effect of after-treatment devices and sampling conditions on the exhaust aerosol characteristics.However, it should be stressed that modeling of diesel-exhaust processes is still in an early phase and further work is merited to better understand the processes and mechanisms involved.

show abstract

Section: Effect Of Aging Time On Particlesmentioning

confidence: 99%

“…Furthermore, Mathis et al (2004a) -Khalek et al, 1998;Mathis et al, 2004b;Ntziachristos et al, 2004b). Therefore, when NM particles are measured in the laboratory, one needs to distinguish between effects attributed to either the source (vehicle and fuel) or the sampling system and conditions.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Investigation of the Nucleation Mode Formation Downstream of Diesel After-treatment Devices

Vouitsis

Ntziachristos

Samaras

2008

Aerosol Air Qual. Res.

View full text Add to dashboard Cite

show abstract

“…It is an objective of the project described here to answer this question. Often more than 90% of the nanoparticles emitted by engines are formed from volatile particle precursors during exhaust dilution [25][26][27]. These precursors are presumably the lower vapor pressure compounds usually associated with Diesel particulate matter, like sulfuric acid and condensable hydrocarbons.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, the influence of dilution conditions may be even greater when most of the solid carbon is removed from the exhaust. Changes up to nearly four orders of magnitude in nanoparticle concentration with changing dilution conditions were observed when the same engine as used in [26] was fitted with a wall-flow exhaust particle filter [25]. As engines become cleaner, it will become increasingly difficult to make representative measurements of exhaust size distributions.…”

Section: Introductionmentioning

confidence: 99%

Diesel Aerosol Sampling in the Atmosphere

Kittelson

Johnson

Watts

et al. 2000

SAE Technical Paper Series

184

160

View full text Add to dashboard Cite

The University of Minnesota Center for Diesel Research along with a research team including Caterpillar, Cummins, Carnegie Mellon University, West Virginia University (WVU), Paul Scherrer Institute in Switzerland, and Tampere University in Finland have performed measurements of Diesel exhaust particle size distributions under real-world dilution conditions. A mobile aerosol emission laboratory (MEL) equipped to measure particle size distributions, number concentrations, surface area concentrations, particle bound PAHs, as well as CO 2 and NO x concentrations in real time was built and will be described. The MEL was used to follow two different Cummins powered tractors, one with an older engine (L10) and one with a state-of-the-art engine (ISM), on rural highways and measure particles in their exhaust plumes. This paper will describe the goals and objectives of the study and will describe representative particle size distributions observed in roadway experiments with the truck powered by the ISM engine.

show abstract

“…Maintaining atmospheric dilution conditions is vital to the achievement of representative sampling (Abdul-Khalek et al 1998;Lodge 1989). The effects of dilution conditions on particle formation and size distributions have been studied by many researchers including Harris andMaricq (2001), Ntziachristos et al (2004), and Liu et al (2007).…”

Section: Secondary Micro-dilutermentioning

confidence: 99%

A Source Dilution Sampling System for Characterization of Engine Emissions under Transient or Steady-State Operation

Liu

Swor

Schauer

et al. 2008

Aerosol Science and Technology

View full text Add to dashboard Cite

With increasingly stringent regulations being placed upon engine emissions, an in-depth understanding of engine exhaust composition will be necessary to assess environmental and health impacts and to develop better methods of reducing emission levels. Source sampling systems have commonly utilized partial sampling techniques, which may introduce the potential for particle loss, and steady-state operation, which is incapable of imitating transient engine conditions. In order to simulate atmospheric dilution and aging conditions, maintain proportional sampling throughout temperature excursions during transient operation, and minimize particle loss, while representatively taking multiple samples from the exhaust flow, a full-partial-full source dilution sampling system was developed. The system consists of a critical flow venturi-constant volume system for primary dilution, a thermophoresis-resistant secondary micro-diluter, a residence time chamber, isokinetic sampling probes, multiple sampling trains, and control systems. Further, the system was designed to prevent particle loss and secondary reactions by reducing wall effects, implementing inert materials, optimizing smooth flow transition, and minimizing electrostatic forces. An examination of the system was conducted by performing a tracer study and by determining the variations in flow rates, gaseous concentrations, and PM mass measurements. Further, a statistical analysis was performed to study the capability and performance of the sampling system. The results suggest that the system was capable of collecting similar samples among the sampling trains and displaying sufficient agreement with a certification system. Therefore, the source dilution sampling system developed in this study is suitable for collecting representative samples from an exhaust flow under transient or steady-state conditions.

show abstract

Diesel Trap Performance: Particle Size Measurements and Trends

Cited by 74 publications

References 15 publications

Theoretical Investigation of the Nucleation Mode Formation Downstream of Diesel After-treatment Devices

Theoretical Investigation of the Nucleation Mode Formation Downstream of Diesel After-treatment Devices

Diesel Aerosol Sampling in the Atmosphere

A Source Dilution Sampling System for Characterization of Engine Emissions under Transient or Steady-State Operation

Contact Info

Product

Resources

About