2020-01-2203 Published 15 Sep 2020 Particulate Matter (PM) Emissions of Euro 5 and Euro 6 Vehicles Using Systems with Evaporation Tube or Catalytic Stripper and 23 nm or 10 nm Counters Barouch Giechaskiel Joint Research Centre (JRC) Joseph Woodburn, Andrzej Szczotka, and Piotr Bielaczyc BOSMAL Automotive R&D Institute Ltd Citation: Giechaskiel, B., Woodburn, J., Szczotka, A., and Bielaczyc, P., “Particulate Matter (PM) Emissions of Euro 5 and Euro 6 Vehicles Using Systems with Evaporation Tube or Catalytic Stripper and 23 nm or 10 nm Counters,” SAE Technical Paper 2020-01-2203, 2020, doi:10.4271/2020-01-2203. Abstract P article number (PN) emission limits were introduced in the European Union’s regulations for light-duty and heavy duty vehicles in the years 2011-2014. Since then, PN measurements have become a common practice in the automotive sector. Many studies showed that the current meth- odology, which counts particles >23 nm, misses a large fraction of particles for some engine technologies, such as port fuel injection vehicles or vehicles fueled with compressed natural gas (CNG). However, data for the latest technology vehicles are lacking. For this reason, we measured PN emissions >23 nm and >10 nm of >30 CNG, gasoline and diesel-fueled vehicles. Two systems were measuring in parallel from the full dilution tunnel; one with an evaporation tube and the other with a catalytic stripper. Te PN emission levels spanned over three orders of magnitude depending on whether there was a particu- late flter installed or not. Te diferences between the two systems (>23 nm) were on average 6%, indicating that a cata- lytic stripper could justifably be permitted in future PN regula- tions. Te ratio of 10-23 nm particles to >23 nm particles ranged from negligible up to many times higher. In many cases, sub-23 nm particles were emitted during cold start. During some high speed events, solid sub-23 nm particles were measured, but they were attributed to release of solid particles from the silicone adaptors. All particulate matter (PM) mass emissions were lower than 4.5 mg/km and <2 mg/km for vehicles equipped with particulate flters. Tere was no apparent correlation between PM mass and PN >23 nm or >10 nm. Introduction I n the European Union (EU) the introduction of a nonvola- tile particle number (PN) limit of 6×10 11 p/km in 2011 (with Euro 5b) for compression ignition engines practically forced the introduction of wall fow diesel particulate flters (DPFs) at diesel fueled vehicles [1]. Later in 2014 the PN limit was extended to spark ignition direct injection engines (SIDI) to address their high PN emissions, but with a 10 times higher PN limit for the frst 3 years. Te introduction of the real- driving emissions (RDE) regulation in 2017, that required compliance with the emission limits also during on-road driving, in combination with the laboratory 6×10 11 p/km limit, practically forced gasoline particulate flters (GPF) at all SIDI vehicles in Europe [2]. Although there are no diferences between the principle of operation of GPFs and DPFs, their operational environment is diferent. GPFs work at higher exhaust gas temperatures with no (or low) presence of oxygen and NO 2 , and lower engine out soot. GPFs are continuous regenerating afertreatment systems that typically regenerate at fuel cut-ofs [3]. Te partic- ulate flters at diesel and SIDI vehicles make them clean under most, if not all, driving conditions. Tere are some concerns however during regeneration events that can increase orders of magnitude the PN emissions [1, 4]. Te current under- standing is that even taking these emissions into account, the weighted PN emissions remain below the respective limits [5, 6]. Some technologies without particulate flters can emit high nonvolatile PN concentrations under some engine oper- ating conditions, and in some cases they can even exceed the limit [5]. It was also found that a large percentage of particles may reside below the currently regulated lower particle size (23 nm) [5, 7]. For example, a nonvolatile nucleation mode has been measured with SIDI [8] or PFI (port fuel injection) vehicles [9, 10], during engine braking [11], or urea injection for heavy duty engines [12]. Te concentration of sub-23 nm particles can be as high as the concentration of >23 nm [5]. For this reason, the PMP (Particle Measurement Programme) group developed a test procedure to count particles >10 nm, but with simple modifcations of the existing PN systems. Te main parts of PN systems are the volatile particle remover (VPR) and the condensation particle counter (CPC). Downloaded from SAE International by Barouch Giechaskiel, Friday, September 11, 2020