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Technical Paper

VERTdePN Quality Test Procedures of DPF+SCR Systems

2014-04-01
2014-01-1579
The combined exhaust gas aftertreatment systems (DPF+SCR) are the most efficient way and the best available technology (BAT) to radically reduce the critical Diesel emission components particles (PM&NP) and nitric oxides (NOx). SCR (selective catalytic reduction) is regarded as the most efficient deNOx-system, diesel particle filters are most efficient for soot abatement. Today, several suppliers offer combined systems for retrofitting of HD vehicles. Quality standards for those quite complex systems and especially for retrofit systems are needed to enable decisions of several authorities and to estimate the potentials of improvements of the air quality in highly populated agglomerations. The present paper informs about the VERTdePN *) quality test procedures, which were developed in an international network project with the same name 2007-2011 (VERT … Verification of Emission Reduction Technologies; dePN … decontamination, disposal of PM / NP and of NOx).
Technical Paper

VERT Particulate Trap Verification

2002-03-04
2002-01-0435
Particulate traps are mechanical devices for trapping soot, ash and mineral particles, to curtail emissions from Diesel engines. The filtration effectiveness of traps can be defined, independent of the pertinent engine, as a function of the particle size, space velocity and operating temperature. This method of assessment lowers cost of certifying traps for large-scale retrofitting projects [1,2]. VERT [3] is a joint project of several European environmental and occupational health agencies. The project established a trap-verification protocol that adapts industrial filtration standards [4] to include the influence of soot burden and trap regeneration phenomena. Moreover, it verifies possible catalytic effects from coating substrates and deposited catalytic active material from engine wear or fuel/ lubricant additives.
Technical Paper

Urban Air Quality Improvements by Means of Vehicular Diesel Particle Filters

2008-04-14
2008-01-0336
The project objective was to investigate the ultrafine solid particle emissions of the prevalent traffic, by performing field measurements at an urban traffic artery in Zurich/Switzerland. Subsequently, various scenarios were postulated to assess the potential of the diesel particle filters (DPF) to improve curbside air quality. Soot aerosols are known to be carcinogenic [1]. If all heavy-duty diesel vehicles were equipped with DPFs, then the number of particles emitted from the entire vehicle fleet could be reduced by 75 to 80%. For PM10, the curtailment scope is considerably lower, around 20%, because more than half of those emissions are not from the exhaust and therefore would not be filtered.
Technical Paper

Testing of SCR-Systems on HD-Vehicles-TeVeNOx

2014-04-01
2014-01-1569
The selective catalytic reduction SCR is extensively used for NOx reduction of recent HD-vehicles. There are some manufacturers and some applications of SCR as retrofit systems (mostly for the low emission zones LEZ and in combination with a DPF). In charge of Swiss authorities AFHB investigated several SCR-systems, or (DPF+SCR)-systems on HD-vehicles and proposed a simplified quality test procedure of those systems. This procedure can especially be useful for the admission of retrofit systems but it can also be helpful for the quality check of OEM-systems. The project name was TeVeNOx - Testing of Vehicles with NOx reduction systems. In the present paper the test procedures will be described and some specific results will be discussed.
Technical Paper

Retrofitting TRU-Diesel Engines with DPF-Systems Using FBC and Intake Throttling for Active Regeneration

2005-04-11
2005-01-0662
Transport Refrigeration Units (TRU) powered by small diesel engines emit high PM and cause locally high PM levels. The concomitant health risks spurred efforts to devise a cost-effective curtailment of these emissions. Diesel particulate filters (DPF) of ceramic honeycomb construction very efficiently trap PM emissions, even ultrafines in the lung penetrating size range of below 300 nm. A fuel borne catalyst (FBC) can facilitate trap regeneration, by lowering the exhaust temperature requirements, but cannot alone guarantee reliable regeneration under all operating conditions of the TRU. A Swiss development team together with industrial partners therefore developed a fully automatic active regeneration system for the California Air Resources Board.
Journal Article

Research on Emissions and Engine Lube Oil Deterioration of Diesel Engines with BioFuels (RME)

2011-04-12
2011-01-1302
In the diesel sector the fatty acid methyl esters (FAME's) - in Europe mostly RME (rapeseed methyl ester) and in US mostly SME (soja oil methyl ester) - are used as a various share, % volume blends with the diesel fuel (B5, B7, B10, B20, Bxx). The present joint project focuses on RME being the most important representative of the biofuels of 1st generation in Europe. The influences of RME blend fuels on emissions and on lube oil deterioration are emphasized. Emissions were investigated on a modern engine with exhaust gas aftertreatment devices like SCR and (DPF+ SCR). Beside the legally limited exhaust emission components some non-legislated like NO₂, N₂O, NH₃ and nanoparticles were measured at stationary and dynamic engine operation.
Technical Paper

Reliability of DPF-Systems: Experience with 6000 Applications of the Swiss Retrofit Fleet

2004-03-08
2004-01-0076
The Swiss 1998 Ordinance on Air Pollution Control (OAPC) mandates curtailment of carcinogenic Diesel particle emissions at construction sites [4]. In addition particle traps are compulsory at underground workplaces [3]. In compliance, more than 6,000 Diesel engines were retrofitted with different particle trap systems. Many traps surpassed 99% filtration efficiency, from the beginning, and secondary emissions were mostly prevented. However, trap failure due to mechanical and thermal damage was initially rather high at about 10%. By Y-2000 the failure rate was halved to about 6%. Thanks to focussed improvements, the Y-2003 statistics show yearly failures of “only” about 2%. The Swiss target is to retrofit 15,000 construction machines with traps, fully compliant with environmental directives, having 5,000 operating hours durability and failure rates below 1%. Construction machines have much higher PM-emission factors than trucks, and are operated more intensely than tractors.
Technical Paper

Particulate Traps for Retro-Fitting Construction Site Engines VERT: Final Measurements and Implementation

1999-03-01
1999-01-0116
1 The VERT project aimed at curtailing the construction site diesel emissions of ultra-fine particles to 1% of the raw emissions. Thus, compliance with occupational health legislation should be achieved. Particulate traps have attained this target. In contrast, engine tuning, reformulated fuels and oxidation catalytic converters are almost ineffective. This paper reports on the concluding project stage in which 10 traps were field tested during 2 years. Subsequent detailed measurements confirmed the excellent results: > 99% filtration rate was achieved in the nano-particulate range. The PAH, too, were very efficiently eliminated. Trap deployment becomes therefore imperative to fulfill VERT-targets.
Technical Paper

Particulate Traps for Construction Machines Properties and Field Experience

2000-06-19
2000-01-1923
1 Occupational Health Authorities in Germany and Switzerland require the use of particulate traps (PT) on construction machines used in underground and in tunneling since 1994. Swiss EPA has extended this requirement 1998 to all construction sites which are in or close to cities. During the VERT*-project, [1, 2, 3, 4, 5]**, traps systems were evaluated for this purpose and only those providing efficiencies over 95% for ultrafine particles < 200 nm have received official recommendation. 10 trap-systems are very popular now for these application, most of them for retrofitting existing engines. Efficiency data will be given as well as experience during a 2-years authority-controlled field test. LIEBHERR, producing their own Diesel engines in Switzerland and construction machines in Germany is the first company worldwide supplying particulate traps as OEM-feature (Original Equipment Manufacturing) on customers request.
Technical Paper

Particulate Traps Used in City-Buses in Switzerland

2000-06-19
2000-01-1927
1 Switzerland is enforcing the use of particulate traps for offroad applications like construction as well as for occupational health applications like tunneling. This decision is based on the results of the VERT-project (1994-1999), which included basic aerosol research, bench screening and field testing of promising solutions as well as the development of implementation tools like trap specification, certification scheems and field control measures. On the other hand there is no corresponding regulation for city-buses yet although PM 10 is about 2× above limit in most Swiss cities. Public pressure however is growing and city transport authorities have reacted by retrofitting Diesel city-buses instead of waiting for cleaner engine technology or CNG-conversions. The favored trap system with about 200 retrofits so far is the CRT.
Technical Paper

Particle Size Distribution Downstream Traps of Different Design

1995-02-01
950373
High levels of particulate emissions from Diesel engines, in tunnel construction sites, force the aftertreatment of exhaust gases with particulate traps. Sub-micron particulates are suspected to be carcinogenic. Hence, the size distribution of particulates was compared for different particulate trap systems. The two extreme types are the ceramic monolith surface filter and the typical deep-bed filter of knitted fiber. These two types have distinctly different properties. The gravimetric evaluation of both systems show comparable efficiencies around 90%. If, instead, the particle count is evaluated: the efficiency of the surface filter drops below 70%, whereas that of the deep-bed filter increases. The spectral analysis of distinct solid particulates shows that the efficiency of the surface filter deteriorates for particles smaller than 100 nm. The toxicological consequences are disquieting.
Technical Paper

Particle Filter Properties after 2000 hrs Real World Operation

2008-04-14
2008-01-0332
Diesel particle filters (DPFs) efficiently eliminate soot, fuel-, and oil-ash emissions of diesel engines, but little data are available with respect to long term aging or deterioration effects of DPFs under real world operating conditions. Aging of wash coat- and catalyst-materials, catalyst poisoning, ash sintering, adsorption and long lasting storage of semi- or non-volatile substances can take place, which over time may influence filtration and conversion properties of DPFs. Herein we report to what extent DPF aging may affect particle filtration characteristics. We compared particle number concentrations (PN), and particle mass (PM) emissions after a 2000 operating hours endurance test (VFT2). Such a controlled field test is required by VERT verification procedures, which lately were published as a national standard (SNR 277205).
Technical Paper

Particle Emissions of Modern Handheld Machines

2014-11-11
2014-32-0036
The progressing exhaust gas legislation for on- and off-road vehicles includes gradually the nanoparticle count limits. The invisible nanoparticles from different emission sources penetrate like a gas into the living organisms and may cause several health hazards. The present paper shows some results of a modern chain saw with & without oxidation catalyst, with Alkylate fuel and with different lube oils. The measurements focused specially on particulate emissions. Particulates were analysed by means of gravimetry (PM) and granulometry SMPS (PN). In this way the reduction potentials with application of the best materials (fuel, lube oil, ox-cat.) were indicated. It has been shown that the particle mass (PM) and the particle numbers (PN), which both consisting almost exclusively of unburned lube-oil, can attain quite high values, but can be influenced by the lube oil quality and can be considerably reduced with an oxidation catalyst.
Technical Paper

PN-Emissions of Gasoline Cars MPI and Potentials of GPF

2018-04-03
2018-01-0363
Further efforts to reduce the air pollution from traffic are undertaken worldwide and the filtration of exhaust gas will also be increasingly applied on gasoline cars (GPF1 … gasoline particle filter). In the present paper, some results of investigations of nanoparticles from four MPI gasoline cars are represented. The measurements were performed at vehicle tailpipe and in CVS-tunnel. Moreover, two variants of GPF were investigated on a high-emitting modern vehicle, including analytics of PAH and attempts of soot loading in road application. The modern MPI vehicles can emit a considerable amount of PN, which in some cases attains the level of Diesel exhaust gas without DPF and can pass over the actual European limit value for GDI (6.0 x 1011 #/km). The GPF-technology offers in this respect further poten-tials to reduce the PN-emissions of traffic.
Technical Paper

Nanoparticle Emissions of DI Gasoline Cars with/without GPF

2017-03-28
2017-01-1004
In the present paper some results of investigations of nanoparticles from five DI gasoline cars are represented. The measurements were performed at vehicle tailpipe and in CVS-tunnel. Moreover, five variants of “vehicle - GPF” were investigated. These results originate from the project GasOMeP (Gasoline Organic & Metal Particulates), which focused on metal-nanoparticles (including sub 20nm) from gasoline cars with different engine technologies. The PN-emission level of the investigated GDI cars in WLTC without GPF is in the same range of magnitude very near to the actual limit value of 6.0 × 1012 #/km. With the GPF’s with better filtration quality, it is possible to lower the emissions below the future limit value of 6.0 × 1011 #/km. There is no visible nuclei mode and the ultrafine particle concentrations below 10mm are insignificant. Some of the vehicles show at constant speed operation a periodical fluctuation of the NP-emissions, as an effect of the electronic control.
Technical Paper

NO2-Formation in Diesel Particle Filter Systems

2013-04-08
2013-01-0526
NO₂ is much more toxic than NO. The average proportion of NO₂ in exhaust gases of vehicles increases significantly due to the use of oxidation catalysts and catalytic coatings in the exhaust gas systems during the last decades combined with generalization of using low sulfur fuels. Diesel oxidation catalysts (DOC) and Pt-containing DPF coatings are widely used to support the regeneration of particle filters, being a source of strongly increased production of NO₂. The present work shows some examples and summarizes the experiences in this matter performed 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.
Technical Paper

Metal Oxide Particle Emissions from Diesel and Petrol Engines

2012-04-16
2012-01-0841
All internal combustion piston engines emit solid nanoparticles. Some are soot particles resulting from incomplete combustion of fuels, or lube oil. Some particles are metal compounds, most probably metal oxides. A major source of metal compound particles is engine abrasion. The lube oil transports these abraded particles into the combustion zone. There they are partially vaporized and ultrafine oxide particles formed through nucleation [1]. Other sources are the metallic additives to the lube oil, metallic additives in the fuel, and debris from the catalytic coatings in the exhaust-gas emission control devices. The formation process results in extremely fine particles, typically smaller than 50 nm. Thus they intrude through the alveolar membranes directly into the human organism. The consequent health risk necessitates a careful investigation of these emissions and effective curtailment.
Technical Paper

Investigations of SDPF -Diesel Particle Filter with SCR Coating for HD-Applications

2015-04-14
2015-01-1023
Diesel exhaust gas aftertreatment systems, which include the selective catalytic reduction (SCR)*) for reduction of NOx are necessary to fulfil the latest legal requirements and are extensively used in the heavy duty (HD) sector. The present paper informs about some results obtained with SCR and with SDPF (a DPF with SCR-coating) on a medium duty research engine Iveco F1C. Beside the limited gaseous emission components NH3, NO2 and N2O were measured. The analysis of nanoparticle emissions was performed with SMPS and CPC. The integration of functions of filtration and NOx-reduction in one element of exhaust aftertreatment system offers several advantages and is widely investigated and considered as a market solution.
Technical Paper

Investigations of NO2 in Legal Test Procedure for Diesel Passenger Cars

2015-09-06
2015-24-2510
As a result of increased use of catalytic exhaust aftertreatment systems of vehicles and the low-sulfur Diesel fuels there is an increasing share of nitrogen dioxide NO2 in the ambient air of several cities. This is in spite of lowering the summary nitric oxides NOx emissions from vehicles. NO2 is much more toxic than nitrogen monoxide NO and it will be specially considered in the next legal testing procedures. There are doubts about the accuracy of analyzing the reactive substances from diluted gas and this project has the objective to show how NO2 is changing as it travels down through the exhaust- and the CVS systems. For legal measurements of NO2 a WLTP-DTP subgroup (Worldwide Light Duty Test Procedures - Diesel Test Procedures) proposed different combinations of NOx-analyzers and analysis of NO and NOx. Some of these set-ups were tested in this work.
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