On-road emissions from urban buses with SCR+Urea and EGR+DPF systems using diesel and biodiesel

López, José M.; Jiménez, Felipe; Aparicio, Francisco; Flores, Nuria

doi:10.1016/j.trd.2008.07.004

Cited by 77 publications

(34 citation statements)

References 11 publications

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“…Because it leads to an increase in HC and CO emissions and low NO x conversion efficiency compared to SCR and LNT, EGR lags behind. In many applications, these technologies can be used as combination to increase NO x conversion efficiency (Xu and McCabe 2012;Lopez et al 2009). With all other advanced aftertreatment devices, sulfur content in the combustion fuel is an important problem for SCR catalyst.…”

Section: Selective Catalytic Reduction (Scr)mentioning

confidence: 99%

The pollutant emissions from diesel-engine vehicles and exhaust aftertreatment systems

Reşi̇toğlu

Altınışık

Keskïn

2014

Clean Techn Environ Policy

816

353

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Diesel engines have high efficiency, durability, and reliability together with their low-operating cost. These important features make them the most preferred engines especially for heavy-duty vehicles. The interest in diesel engines has risen substantially day by day. In addition to the widespread use of these engines with many advantages, they play an important role in environmental pollution problems worldwide. Diesel engines are considered as one of the largest contributors to environmental pollution caused by exhaust emissions, and they are responsible for several health problems as well. Many policies have been imposed worldwide in recent years to reduce negative effects of diesel engine emissions on human health and environment. Many researches have been carried out on both diesel exhaust pollutant emissions and aftertreatment emission control technologies. In this paper, the emissions from diesel engines and their control systems are reviewed. The four main pollutant emissions from diesel engines (carbon monoxide-CO, hydrocarbons-HC, particulate matter-PM and nitrogen oxides-NO x ) and control systems for these emissions (diesel oxidation catalyst, diesel particulate filter and selective catalytic reduction) are discussed. Each type of emissions and control systems is comprehensively examined. At the same time, the legal restrictions on exhaust-gas emissions around the world and the effects of exhaust-gas emissions on human health and environment are explained in this study.

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Section: Selective Catalytic Reduction (Scr)mentioning

confidence: 99%

The pollutant emissions from diesel-engine vehicles and exhaust aftertreatment systems

Reşi̇toğlu

Altınışık

Keskïn

2014

Clean Techn Environ Policy

816

353

View full text Add to dashboard Cite

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“…In a recent study, EF PN was measured at the kerbside for individual vehicles for real-world dilution (Hak et al, 2009). Along with particles, nitrogen oxides, NO x , are depicted as being the most problematic pollutant from internal combustion engines (Lopez et al, 2009). In order to meet the lower NO x and particle emission levels introduced for heavy duty vehicles (HDVs), exhaust gas after-treatment has become necessary.…”

Section: å M Hallquist Et Al: Particle and Gaseous Emissions Fmentioning

confidence: 99%

“…In Lopez et al (2009) a Euro IV diesel-fuelled bus equipped with EGR and DPF and a Euro IV diesel-fuelled bus equipped with SCR were analysed for a full driving cycle for which EF PM were determined to be 49 ± 1 and 73 ± 4 mg vehicle −1 km −1 , respectively. In this study no Euro IV with SCR were studied, but Euro V were studied, and the average EF PM for these buses (when excluding one extreme) was 68 ± 11 mg vehicle −1 km −1 .…”

Section: å M Hallquist Et Al: Particle and Gaseous Emissions Fmentioning

confidence: 99%

“…In this study no Euro IV with SCR were studied, but Euro V were studied, and the average EF PM for these buses (when excluding one extreme) was 68 ± 11 mg vehicle −1 km −1 . Two Euro IV diesel-fuelled buses equipped with EGR and DPF were tested: one gave similar EF PM to Lopez et al (2009), 55 mg vehicle −1 km −1 , and the other significantly higher EF PM , 201 mg vehicle −1 km −1 .…”

Section: å M Hallquist Et Al: Particle and Gaseous Emissions Fmentioning

confidence: 99%

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Particle and gaseous emissions from individual diesel and CNG buses

et al. 2013

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In this study size-resolved particle and gaseous emissions from 28 individual diesel-fuelled and 7 compressed natural gas (CNG)-fuelled buses, selected from an in-use bus fleet, were characterised for real-world dilution scenarios. The method used was based on using CO₂ as a tracer of exhaust gas dilution. The particles were sampled by using an extractive sampling method and analysed with high time resolution instrumentation EEPS (10 Hz) and CO₂ with a non-dispersive infrared gas analyser (LI-840, LI-COR Inc. 1 Hz). The gaseous constituents (CO, HC and NO) were measured by using a remote sensing device (AccuScan RSD 3000, Environmental System Products Inc.). Nitrogen oxides, NO_x, were estimated from NO by using default NO₂/NO_x ratios from the road vehicle emission model HBEFA3.1. The buses studied were diesel-fuelled Euro III–V and CNG-fuelled Enhanced Environmentally Friendly Vehicles (EEVs) with different after-treatment, including selective catalytic reduction (SCR), exhaust gas recirculation (EGR) and with and without diesel particulate filter (DPF). The primary driving mode applied in this study was accelerating mode. However, regarding the particle emissions also a constant speed mode was analysed. The investigated CNG buses emitted on average a higher number of particles but less mass compared to the diesel-fuelled buses. Emission factors for number of particles (EF_PN) were EF_{PN, DPF} = 4.4 ± 3.5 × 10¹⁴, EF_{PN, no DPF} = 2.1 ± 1.0 × 10¹⁵ and EF_{PN, CNG} = 7.8 ± 5.7 ×10¹⁵ kg fuel⁻¹. In the accelerating mode, size-resolved emission factors (EFs) showed unimodal number size distributions with peak diameters of 70–90 nm and 10 nm for diesel and CNG buses, respectively. For the constant speed mode, bimodal average number size distributions were obtained for the diesel buses with peak modes of ~10 nm and ~60 nm. Emission factors for NO_x expressed as NO₂ equivalents for the diesel buses were on average 27 ± 7 g (kg fuel)⁻¹ and for the CNG buses 41 ± 26 g (kg fuel)⁻¹. An anti-relationship between EF_{NO_x} and EF_PM was observed especially for buses with no DPF, and there was a positive relationship between EF_PM and EF_CO

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“…The integrated NO x and PM systems were also introduced for the first time in passenger cars by Toyota in Europe (2003) and by Mercedes in the US (2006) [5]. Furthermore, combinations of aftertreatment technologies with the use of various fuel blends have also been reported in some studies to control diesel engine exhaust emissions [6,7]. The urea-SCR system is a well-known and promising technology with the potential to reduce NO x pollutants by over 70% in the European steady-state cycle (ESC) and the European transient cycle (ETC) [8], to reduce both NO x and PM on cold US-Transient and hot US-Transient cycles [9], and to improve the economy of the engine together with the abatement of NO x pollutants [10].…”

Section: Introductionmentioning

confidence: 99%

Impact of a Urea-Selective Catalytic Reduction System on Volatile Organic Compound Emissions from a Diesel Engine

Shah

Jiang

2011

Arab J Sci Eng

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The impact of a vanadium based urea-water selective catalytic reduction (SCR) system on volatile organic compounds emissions from the tailpipe of a diesel engine were studied. The engine was run on an AC electrical dynamometer in an 8-mode steady-state cycle and the gas-phase VOCs were collected in Tenax TA ® tubes from diluted exhaust. Collected samples were extracted by a thermal desorber and analyzed by gas chromatograph-mass spectrometry. It was found that VOCs were in abundance under a full engine load upstream and downstream of the SCR system and that the SCR positively abated these pollutants. Toluene exhibited the maximum relative contribution (RC) to total VOCs at about 43 and 48% upstream and downstream of the SCR, respectively. After toluene, benzene, ethyl benzene, and undecane were the next major contributors, with a similar order of magnitude. Styrene and butyl acetate were the lowest relative contributors. The RC of benzene was reduced but those of toluene and ethyl benzene were increased downstream of the SCR. The VOC conversion rate (CR) exceeded 17% over the catalyst temperature and space velocity ranges 321-435 • C and 27.63 × 10 3 -37.94 × 10 3 h −1 , respectively. The optimum catalyst temperature was 321 • C, giving a maximum CR of 33%. The CR of benzene and styrene revealed maxima during the full-load modes and minima during the lowest-load modes of the cycle. The CR of benzene increased with increasing catalyst temperature.

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On-road emissions from urban buses with SCR+Urea and EGR+DPF systems using diesel and biodiesel

Cited by 77 publications

References 11 publications

The pollutant emissions from diesel-engine vehicles and exhaust aftertreatment systems

The pollutant emissions from diesel-engine vehicles and exhaust aftertreatment systems

Particle and gaseous emissions from individual diesel and CNG buses

Impact of a Urea-Selective Catalytic Reduction System on Volatile Organic Compound Emissions from a Diesel Engine

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