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Technical Paper

Testing of Combined DPF+SCR Systems for HD-retrofitting – VERTdePN

2009-04-20
2009-01-0284
New Diesel exhaust gas aftertreatment systems, with combined DPF*) and deNOx (mostly SCR) systems represent a very important step towards zero emission Diesel fleet. These combined systems are already offered today by several suppliers for retrofitting of HD vehicles. Reliable quality standards for those quite complex systems are urgently needed to enable decisions of several authorities. The present report informs about the international network project VERT *) dePN (de-activation, de-contamination, disposal of particles and NOx), which was started in Nov. 2006 with the objective to introduce the SCR-, or combined DPF+SCR-systems in the VERT verification procedure. Examples of results for some of the investigated systems are given. These investigations included parameters, which are important for the VERT quality testing: besides the regulated gaseous emissions several unregulated components such as NH3, NO2 and N2O were measured.
Technical Paper

Filtration of Diesel Soot Nanoparticles and Reliability in Swiss HDV Retrofitting

2005-01-19
2005-26-015
Based on the emission inventory Fig. 1, the Swiss 1998 Ordinance on Air Pollution Control (OAPC) mandates curtailment of carcinogenic diesel particle emissions at type B construction sites [1]. Moreover, particle traps are compulsory at underground workplaces [2]. In compliance, more than 6,000 Diesel engines were retrofitted with various particle trap systems. Many traps surpassed 99% filtration efficiency and secondary emissions were mostly prevented. However, trap failure due to mechanical and thermal damage was initially rather high at about 10%. By the year 2000 the failure rate was halved to about 6%. Thanks to focussed improvements, the year 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%. Traps must pass the VERT suitability test before deployment.
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