Diesel Particulate Emissions of Passenger Cars - New Insights into Structural Changes During the Process of Exhaust Aftertreatment Using Diesel Oxidation Catalysts

Klein, Hans‐Friedrich; Lox, E.S.; Kreuzer, Thomas; Kawanami, M.; Ried, Thomas; Bächmann, K.

doi:10.4271/980196

Cited by 24 publications

(15 citation statements)

References 6 publications

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“…As the amount of molecular oxygen is increased, there is a reduction in the formation of fuel fragments, a larger portion of carbon leaves the rich premixed zone as CO. It is has been suggested that oxygenates have a lower flame temperature, thus changing the rate of vaporization and the local air-fuel equivalence ratio [47]. Similar results have been found…”

Section: Oxygenatessupporting

confidence: 79%

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Effects of Oxygenated Fuels on DI Diesel Combustion and Emissions

Hallgren

Heywood

2001

SAE Technical Paper Series

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Emissions from compression ignition (CI) engines are being placed under stricter regulations. The use of oxygenated fuels has been proposed as a means of complying with future emission levels. Previous research on oxygenates has suggested the presence of molecular oxygen within the fuel significantly reduces the formation of particulate matter (PM). The PM reduction is logarithmic and correlates with the weight percent of oxygen in the fuel and not with other properties such as chemical structure and volatility. However, many studies fail to correctly decouple the effects of oxygenates from other fuel properties that impact emission levels; such as cetane number, density, aromatic content, and volatility.Mechanisms responsible for changes in the combustion process and emissions were investigated with a matrix containing 14 fuels, addressing oxygenate proportionality, structure, volatility, equivalent structure without oxygen, and changes in the base diesel fuel. A scanning mobility particle sizer (SMPS) was used to evaluate changes in particle size distributions, in addition to gravimetric filter and oxides of nitrogen (NOx) measurements.Engine emissions tests were conducted using a Ricardo Hydra MK IV direct injection (DI) diesel engine. The sensitivity of engine operation parameters to intake temperature, load, injection timing, and ignition delay (ID) were evaluated with the baseline fuel. All fuels in the matrix were matched for total released energy and combustion phasing, using a cetane improving additive. The changes in emission have been quantified with agreement between the relative trends observed with the integrated SMPS volume concentrations and filter measurements. In order to evaluate changes among fuels and measurements taken with the SMPS, various fuels were subjected to physical and chemical characterization in order to determine morphological and compositional changes.

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Section: Oxygenatessupporting

confidence: 79%

“…Research has shown that within the 3500 C to 4000 C range, high-end volatility has little impact on PM emissions [47]. A small decrease has been observed in NOx as the back-end volatility has been decreased, no effect on PM was noted [15].…”

Section: Laboratories Indicates That There Is a Strong Correlation Bementioning

confidence: 96%

Effects of Oxygenated Fuels on DI Diesel Combustion and Emissions

Hallgren

Heywood

2001

SAE Technical Paper Series

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“…The higher the catalyst temperature, the greater the oxidation rate of gaseous HC until the catalyst reaches its optimum achievable performance, reducing the amount of HC that can be adsorbed onto the particulates. Klein et al 22 also suggested that the reduction in SOM was likely to be a reduction in the gas phase HC rather than the oxidation of adsorbed HC. Thus, the DOC had no influence on the primary particulates (soot cores) as well as the aggregates of primary particles.…”

Section: The Implementation Of a Doc To A Fegr Systemmentioning

confidence: 99%

Filtered EGR – a step towards an improved NOX/soot trade-off for DPF regeneration

et al. 2012

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Exhaust gas recirculation (EGR) is currently widely used in commercial diesel engines to provide an effective solution in reducing the levels of nitrogen oxide (NO X ) emissions. However, this currently comes at the expense of an exponential increase in particulate matter (PM) emissions resulting directly from the dilution effect (i.e. reduction in oxygen availability), as well as a further penalty arising from the recirculation of the exhaust emissions such as soot and hydrocarbons. In our earlier work it was observed that filtered EGR (FEGR) was able to play a significant role in controlling the soot recirculation penalty and thus improve the overall NO X /soot trade-off. In order to further our understanding of the effect of recirculated exhaust gases and in particular recirculated soot and hydrocarbon (HC), comparisons were made between standard EGR, FEGR and pure nitrogen (N 2 ), a direct cleaner replacement of the exhaust gas. When implementing FEGR, a diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) were introduced into the exhaust to not only filter the soot particulates but reduce the recirculation of HC which can play a role in particulate surface growth. It was observed that the recirculated HC species and soot particles (especially at high load and EGR ratios) play a role in promoting the production and growth of further particles within the combustion chamber. Similarly, by comparing at the same O 2 intake concentration as that of FEGR and introducing N 2 as the EGR replacement gas, it was possible to correlate the increase in engineout mass of soot with EGR to the recirculation of soot particles, HC species as well as the presence of H 2 O and CO 2 .

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“…Also DOC has been found to reduce the particulate mass, mainly by reducing the SOF of the particulates (Bagley et al 1998;Vaaraslanti et al 2006). However, the DOC is assumed to reduce the amount of HC in the gas phase, which may result in smaller mass transfer onto the particles when the exhaust cools (Klein et al 1998), resulting in smaller sized particles. Thus, there is a need to investigate the influence of the DOC on particle number concentration and size distribution.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Particulate Emissions of a Methanol Fumigated Diesel Engine Equipped with Diesel Oxidation Catalyst

Zhang

Cheung

Chan

et al. 2011

Aerosol Science and Technology

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In this article, the effects of fumigation methanol, diesel oxidation catalyst, and engine operation parameters (engine load and engine speed) on diesel smoke opacity, particulate mass concentration, particulate number concentration and the soluble organic fraction (SOF) in the particulate were investigated at certain selected operation conditions. Experiments were performed on a 4-cylinder direct injection diesel engine operating at three engine speeds and three loads for each engine speed. For each engine speed, there was a decrease of smoke opacity with increase in the level of fumigation methanol. The reduction was particularly obvious at the high engine load but was not significant at the low and medium engine loads. For all test conditions, fumigation methanol could effectively reduce the particulate mass and number concentrations. However, fumigation methanol increased the fraction of SOF in the particles. The DOC could further reduce the particulate mass and number concentrations as well as the fraction of SOF in the particles when the exhaust gas temperature was sufficiently high.

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Diesel Particulate Emissions of Passenger Cars - New Insights into Structural Changes During the Process of Exhaust Aftertreatment Using Diesel Oxidation Catalysts

Cited by 24 publications

References 6 publications

Effects of Oxygenated Fuels on DI Diesel Combustion and Emissions

Effects of Oxygenated Fuels on DI Diesel Combustion and Emissions

Filtered EGR – a step towards an improved NOX/soot trade-off for DPF regeneration

Experimental Study on Particulate Emissions of a Methanol Fumigated Diesel Engine Equipped with Diesel Oxidation Catalyst

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