Experimental study on the characteristics of nano-particle emissions from a heavy-duty diesel engine using a urea-SCR system

Lee, Seangwock; Cho, Yong Seok; Song, Myoung-Ho; Kim, H.; Park, J.; Baik, Doo-Sung

doi:10.1007/s12239-012-0033-4

Cited by 32 publications

(23 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, a minimum exhaust gas temperature is required (around 200 C) before urea solution injection, in order to ensure a complete decomposition and hydrolysis of urea to ammonia and to avoid catalyst deactivation, by-products and deposits (Brack et al 2016;Guan et al 2014). Images of collected PM with and without urea injection showed that urea-injected particles had sizes from 200 nm to 1 lm (Lee et al 2012). Recent findings have shown that urea injection can also lead to the formation of smaller particles.…”

Section: Introductionmentioning

confidence: 99%

Effect of selective catalytic reduction on exhaust nonvolatile particle emissions of Euro VI heavy-duty compression ignition vehicles

Mamakos

Schwelberger

Fierz³

et al. 2019

Aerosol Science and Technology

View full text Add to dashboard Cite

The nonvolatile particle number (PN) emissions of late technology diesel heavy-duty vehicles (HDV) are very low due to the introduction of Diesel Particulate Filters (DPF). Nevertheless, a large fraction (50%) of particles below the current lower regulated size (23 nm) was recently reported. Moreover, large differences between laboratory and PN Portable Emission Measurement Systems (PN-PEMS) have been observed. In order to better understand such differences, the physical properties of the exhaust aerosol from two Euro VI technology diesel heavy-duty engines were studied. It was found that urea injection leads to formation of nonvolatile particles. The produced particles covered a wide size range spanning from below 10 nm to above 100 nm. As such, they contribute to the regulated PN emissions, with measured concentrations corresponding to as high as 2 Â 10 11 #/kWh over a World Harmonized Transient Cycle (WHTC). However, a large fraction of them was undetected owing to their small particle size. Low-cutoff size (10 nm) Condensation Particle Counters (CPCs) (which are under discussion to be included in the regulations) measured up to twice as high concentrations. Considering the large particle losses in the sampling systems at this size range, the true concentrations can be two times higher from what the low-cutoff CPCs reported. When the temperature of the SCR system exceeded a threshold of 300 C, the produced particles were found to be positively charged, increasing the average exhaust aerosol charge up to þ3 elementary charges per particle. Scanning Mobility Particle Sizer (SMPS) measurements of non-neutralized samples revealed that even the smallest of them can carry more than one positive charge. The findings of this study can explain the differences reported between PEMS and laboratory systems and especially those based on diffusion charging. They also provide insight for a refinement of technical requirements prescribed in the European PEMS regulation to more accurately quantify the PN emissions from such technologies.

show abstract

Section: Introductionmentioning

confidence: 99%

Effect of selective catalytic reduction on exhaust nonvolatile particle emissions of Euro VI heavy-duty compression ignition vehicles

Mamakos

Schwelberger

Fierz³

et al. 2019

Aerosol Science and Technology

View full text Add to dashboard Cite

show abstract

“…Improper values of these parameters may in fact not only impair the abatement efficiency of the system, but also generate deposits and concretions that can provoke irreparable damage to the whole exhaust pipe. Poor urea-water vaporisation was also shown to positively correlate with increased emission of particulate matter [13]. As a consequence, the investigation of the behaviour of UWS in hot-air flow has become a major research topic in recent years.…”

Section: Introductionmentioning

confidence: 99%

A methodology to investigate the behaviour of urea-water sprays in high temperature air flow for SCR de-NOxapplications

Postrioti

Brizi

Ungaro

et al. 2015

Fuel

View full text Add to dashboard Cite

“…8 (diesel bus, China IV) displayed higher PN emission rates in stage 1-2 particles (aerodynamic diameter < 30 nm), which were observed to be consistent with the previous studies. In many studies, in SCR operations, an increase in PM [66,67], the total number of particles [68,69], and the number solid particles of > 23 nm [66] up to three times [39] has been reported. The reason for this was that SCR devices could form new nonvolatile particles in the exhaust pipe of diesel vehicles because of the direct interaction of NH 3 with the catalyst material and the exhaust gas.…”

Section: The Average Pn Size and Particle Mode Distributionmentioning

confidence: 99%

Transient Characterization of Automotive Exhaust Emission from Different Vehicle Types Based on On-Road Measurements

Mao

et al. 2020

Atmosphere

View full text Add to dashboard Cite

Previous works on real-world vehicle emission characteristics have mainly focused on the influences of fuel, speed, vehicle type, elevation, and other factors on vehicle emission quantity and components. However, few studies have investigated the transient trend of automotive exhaust emissions through on-road measurements. The key objective of the present paper was to examine the transient characteristics of exhaust emissions from different vehicle types on the roads of Tianjin. To achieve the goal, a portable emission measurement system (PEMS) was employed to monitor emissions from selected test vehicles—private cars, passenger vehicles, and cargo vehicles. It was found that the high-emission points of test vehicles were mainly distributed in two regions: the high-speed region (speed > 70–90 km/h, vehicle-specific power (VSP) > 0 kW/t) and the medium-speed–acceleration region (20–30 km/h < speed < 60–90 km/h, 0 kW/t <VSP < 12 kW/t). The CO, hydrocarbon (HC), NOx, and particulate number (PN) average emission rates in the high-emission points could be 3.15–14.93 times, 1.93–24.89 times, 3.23–6.03 times, and 3.22–30.27 times of those of average emission rates. The HC, NOx, and PN average emission rates of China IV vehicles in the high-emission points were 2.46–4.92 times, 3.56–6.03 times, and 3.22–13.21 times of those of average emission rates, not less than those of China III (1.93–2.52 times, 2.75–3.90 times, and 9.98–22.34 times). Test vehicles mainly emitted nucleation-mode and Aitken-mode particles, and the increase of the PN concentration emission rate in low-speed and high-speed regions was higher than that in the medium-speed region. The exhaust gas recirculation (EGR) + diesel particulate filter (DPF) could effectively inhibit the Aitken output caused by turbocharged intercooler (CIC). The selective catalytic reduction (SCR) might cause more nucleation-mode particles.

show abstract

Experimental study on the characteristics of nano-particle emissions from a heavy-duty diesel engine using a urea-SCR system

Cited by 32 publications

References 9 publications

Effect of selective catalytic reduction on exhaust nonvolatile particle emissions of Euro VI heavy-duty compression ignition vehicles

Effect of selective catalytic reduction on exhaust nonvolatile particle emissions of Euro VI heavy-duty compression ignition vehicles

A methodology to investigate the behaviour of urea-water sprays in high temperature air flow for SCR de-NOxapplications

Transient Characterization of Automotive Exhaust Emission from Different Vehicle Types Based on On-Road Measurements

Contact Info

Product

Resources

About