Wyniki wyszukiwania - Biblioteka Nauki

1

Conditions of NO2-production in catalyzed DPF-systems

100%

Mayer A. , Czerwinski J. , Zelenka P.

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tom R. 51, nr 3

3-16

EN

NO2 is much more toxic than NO. Due to the use of oxidation catalysts and catalytic coatings in the exhaust gas systems in the last decades and due to the use of low sulphur fuels the average NO2-portion in exhaust gases of vehicles increases. Diesel oxidation catalysts (DOC) and Pt-containing DPF-coatings are generally used to support the regeneration of particle filters, which can be a source of strongly increased NO2-production. The present work shows some examples and summarizes the experiences in this matter elaborated at the Laboratories for IC-Engines & Exhaust Emissions Control (AFHB) of the University of Applied Sciences Biel-Bienne, Switzerland, during some research activities on engine dynamometers in the years 2010-2012. In general it can be stated: 1) with a Pt-coated catalyst (DOC), or with catalytic surface filter (CSF) there is a maximum of NO2/ NOx - ratio typically in the exhaust gas temperature range around 350 °C, 2) with higher Pt-content in the coating there is a higher potential for NO2-formation, 3) lower NO2-production appears with: higher spatial velocity, higher S-content in fuel and with DOC/DPF used and/or soot loaded, 4) in some cases of semi active regeneration systems, or with the use of RME conditions with higher NO2-rates can appear.

PL

W ostatnich dziesięcioleciach w układach wylotowych silników spalinowych zastosowano reaktory utleniające z powłokami katalitycznymi oraz wprowadzono paliwa o niskiej zawartości siarki, czego wynikiem jest wzrost zawartości NO2 w gazach wylotowych silników spalinowych. NO2 jest znacznie bardziej toksycznym związkiem niż NO. Katalityczne reaktory utleniające i filtry cząstek stałych z naniesionymi powłokami zawierającymi platynę są przeważnie wykorzystywane w celu ułatwienia regeneracji filtrów cząstek stałych. W niniejszej pracy zawarto wyniki badań podsumowujące działalność badawczą Laboratoriów Silników Spalinowych i Pomiarów Emisji Spalin, prowadzoną na uniwersytecie w Biel-Bienne (Szwajcaria) w latach 2010-2012. Na podstawie wykonanych badań stwierdzono, że: 1) stosując reaktory utleniające z powłokami zawierającymi platynę lub inny materiał katalityczny maksymalna wartość proporcji NO2/NOx jest osiągana przy temperaturze gazów wylotowych wynoszącej ok. 350 °C, 2) zwiększenie zawartości platyny w powłoce katalitycznej sprzyja zwiększeniu intensywności tworzenia NO2, 3) mniejsza intensywność tworzenia NO2 następuje wraz ze zwiększeniem względnej prędkości przepływu spalin, zwiększeniem zawartości siarki w paliwie oraz dzięki zastosowaniu reaktora utleniającego/filtra cząstek stałych i/lub zapełniony filtr cząstek stałych, 4) w niektórych przypadkach regeneracji półaktywnej oraz podczas stosowania estrów metylowych kwasów tłuszczowych może nastąpić zwiększenie emisji NO2.

2

PN-emissions with increased lube oil consumption of GDI car with/without GPF

88%

Czerwinski J. , Comte P. , Güdel M. , Kurzwart M. , Mayer A.

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2017

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tom Vol. 24, No. 1

102--112

EN

The particle number (PN) emissions are increasingly considered in the progressing exhaust gas legislation for onand off- road vehicles. The invisible nanoparticles penetrate like a gas into the living organisms and cause several health hazards. The present paper shows how the PN- and gaseous emissions of a modern GDI (Abbreviations see at the end of this paper) vehicle change, when there is an in-creased lube oil consumption. What are the potentials of a gasoline particle filter to reduce the emissions? The lube oil consumption was simulated by mixing 2% vol. lube oil into the fuel. A non-coated GPF was mounted at tailpipe, so only the filtration effects were indicated. The tests were performed at transient (WLTC) and at stationary (SSC) operating conditions. It has been shown that the increased lube oil consumption significantly increases the PN-emissions and the applied high quality GPF eliminates these emissions very efficiently.

3

Improvement of air quality in vehicle cabins by nanoparticle filtration

75%

Burtscher H. , Mayer A. , Loretz S. , Keller A. , Kasper M. , Czerwinski J.

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tom Vol. 17, No. 4

79-88

EN

A filter system is presented which allows the reduction of the concentration of ultrafine particles in vehicle cabins to very low levels. The original ventilation system is switched to the recirculation mode and all cabin intake air is supplied via a retrofitted filter system. Tests with a variety of different vehicles (from passenger cars to coaches) show the efficiency of the system. Filters incorporated in present ventilation systems remove large particles, for example pollen, but usually are inefficient for removing very small particles. This is demonstrated by Fig. l, where the particle number concentration outside and inside a car is plotted during a journey near Zurich. It is obvious that the concentrations inside and outside are more or less identical. All windows were closed during this measurement. Tests with a number ofdifferent all cars showed similar results. The filters included in today 's ventilation systems usually cannot remove nanoparticles, and so vehicle cabin indoor and outdoor nanoparticle concentrations are more or less identical. The nanocleaner, consisting of a very effident filter and a high performance blower, allows reduction of the particle concentration in the cabin from several hundreds of thousands or millions per cc. to a few thousand per cc., equivalent to remote woodland, the total exposed dose being reduced by some two orders of magnitude.

4

Vert particle filter test procedure and quality standard for new and in-use diesel engines

75%

Mayer A. , Czerwinski J. , Kasper M. , Leutert G. , Heeb N. V. , Ulrich A. , Jaussi F.

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tom Vol. 17, No. 4

313-322

EN

A new approach is needed to test particle filters for retrofitting Diesel engines. Considering the toxicity of the particles as also the physical and chemical attributes of particle filters, the optimal scheme is to test the components themselves independent of the deployment. That scheme ensures the highest effectiveness with least effort. It also enables evaluation of worst-case situations and assesses the hazards of secondary emissions. The Swiss standard SNR 277 205, which mandates the VERT test procedure, is a first step in that direction. The solution is derived from the physics of the filter media. The filtration of fine particles essentially depends on the particle size and the space velocity. The attributes of the emitting engine are only insignificantly relevant. Hence the physics and chemistry of particle filters can be investigated independent of the engine and its deployment duty. This concept facilitates a very thorough investigation of the size-dependent filtration, aging susceptibility, secondary emissions and extreme situations. Filter systems, which pass this detailed test, perform equally well in every retrofit configuration. This filter test concept was implemented 1998 in the VERT project and is successful for assessing retrofltting [4]. VERT approved fllter systems are already deployed in the Low Emission Zones of Europe, North and South America.

5

EC/OC analysis of particles from 2-S scooters and potentials of improved aftertreatment

75%

Czerwinski J. , Comte P. , Astorga C. , Rey M. , Reutimann F. , Mayer A.

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tom R. 46, nr SC3

165-179

EN

Limited and non-regulated emissions of scooters were analyzed during several annual research programs of the Swiss Federal Office of Environment (RAFU). Small scooters, which are very much used in the congested centers of several cities, are a remarkable source of air pollution. Therefore every effort to reduce the emissions is an important contribution to improve the air quality in urban centers. In the present work detailed investigations of particle emissions of different 2-stroke scooters with direct injection and with carburettor were performed. The nanoparticulate emissions were measured by means of SMPS, (CPC) and NanoMet. Also the particle mass emission (PM) was measured with the same method as for Diesel engines. Extensive analyses of PM-residuum for SOF/INSOF, PAH and toxicity equivalence (TEQ), were carried out in an international project network. Particle mass emission (PM) of 2-S Scooters consists mostly of SOF. The standard coulometric EC/OC-analysis, as well as the analyzer MEXA 1370 PM overestimate the amount of soot due to the effect of "charring", which provokes the heaviest VOC to stay in the sample during the thermal extraction and to be indicated as EC. A solution for this analytical problem is demonstrated. Wiremash Filter Catalyst (WFC) is en efficient measure to intensify the oxidation of the exhaust gas components and to reduce PM, PC, PAH, TEQ and VOC. The presented WFC needs a further development for durability and product integration. WFC is an efficient aftertreatment measure to substantially lower the toxicity of 2-S exhaust gases.