Species Resolved Hydrocarbon Emission Profiles from Advanced Diesel Combustion and Characterization of Heat-up Diesel Oxidation Catalysts PDF Download

Author: Manbae Han
Publisher:
ISBN:
Category :
Languages : en
Pages : 428

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Author: Karishma Vistasp Irani
Publisher:
ISBN:
Category :
Languages : en
Pages : 74

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There has been a growing interest in using lean-burn engines due to their higher fuel economy and associated lower CO2 emissions. However, there are challenges in reducing NOX in an O2-rich (lean-burn) exhaust, and in low temperature soot oxidation. NOX storage/reduction (NSR) and selective catalytic reduction (SCR) are commercial NOX reduction technologies, and both are more efficient with levels of NO2 that are higher than those that are in engine exhaust (engine-out NO2 levels are ~10% of the total NOX). Therefore diesel oxidation catalysts are installed upstream of these technologies to provide NO2 through NO oxidation. The motivation behind this research project was two-fold. The first was to gain a better understanding of the effect of hydrocarbons on NO oxidation over a monolithic diesel oxidation catalyst. The second was to spatially resolve competitive oxidation reactions as a function of temperature and position within the same diesel oxidation catalyst (as that used in the first part). A technique known as spatially resolved capillary-inlet mass spectrometry (SpaciMS) was used to measure the gas concentrations at various positions within the catalyst. Diesel engine exhaust contains a mixture of compounds including NO, CO and various hydrocarbons, which react simultaneously over a catalyst, and each can influence the oxidation rates of the others. While studying the effect of hydrocarbons on NO oxidation in this project, propylene was found to have an apparent inhibition effect on NO oxidation, which increased with increasing propylene concentration. This apparent inhibition is a result of the NO2, as a product of NO oxidation, reacting with the propylene as an oxidant. Experiments with NO2 demonstrate a significant temperature decrease in the onset of NO2 reduction when propylene was present, which decreased further with increasing amounts of propylene, verifying NO2 as an oxidant. Similar results were observed with m-xylene and dodecane addition as well. The results also demonstrate that NO2 was consumed preferentially relative to O2 during hydrocarbon oxidation. With low inlet levels of O2, it was evident that the addition of NO2 had an apparent inhibition effect on propylene oxidation after the onset of NO2 reduction. This subsequent inhibition was due to the NO formed, demonstrating that C3H6 results in reduced NO2 outlet levels while NO inhibits C3H6 oxidation. The development of new models as well as validation of existing models requires the ability to spatially resolve oxidation reactions within a monolith. Spatially-resolved data will also give catalyst manufacturers insight into the location of active fronts, thereby directing the design of more efficient catalysts. In this research project, spatially resolving the oxidation reactions demonstrated that H2 and CO are oxidized prior to C3H6 and C12H26 and clearly show back-to-front ignition of the reductant species. An enhancement in NO oxidation was observed at the same time as dodecane oxidation light off, likely related to dodecane partial oxidation products.

Author: Alexander Knafl
Publisher:
ISBN: 9783836465755
Category : Technology & Engineering
Languages : en
Pages : 164

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The development of low-temperature premixed compression ignition (PCI) combustion strategies and the performance of diesel oxidation catalysts (DOe are presented in this work. At moderate loads, low-temperature PCI combustion is shown to significantly reduce engine-out oxides of nitrogen (NOX) and soot emissions compared to a conventional diesel combustion strategy. The PCI load-range is limited by soot emissions at high engine loads and excessive carbon monoxide (CO), hydrocarbon (He emissions and low exhaust gas temperatures low engine loads. DOC formulations are investigated on a gas bench reactor using surrogate exhaust gas mixtures containing CO, O2, H2O, n1H24, C2H4 and N2. Light-off tests show delayed catalyst light-off in the presence of PCI exhaust. CO and HC are converted to 100% and 98% respectively under fully lit conditions. Engine experiments agree well with reactor experiments. DOC formulations containing zeolites adsorb HC at low temperatures. HC speciation shows that HCs of carbon number five and higher are trapped on zeolite at low temperatures. CO conversion is 100% through the fully active catalyst; HC conversion is lower compared to the reactor experiments.

Author: Society of Automotive Engineers
Publisher:
ISBN:
Category : Air
Languages : en
Pages : 154

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Author:
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ISBN:
Category :
Languages : en
Pages :

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Reactivity Controlled Compression Ignition (RCCI) is a novel combustion process that utilizes two fuels with different reactivity to stage and control combustion and enable homogeneous combustion. The technique has been proven experimentally in previous work with diesel and gasoline fuels; low NOx emissions and high efficiencies were observed from RCCI in comparison to conventional combustion. In previous studies on a multi-cylinder engine, particulate matter (PM) emission measurements from RCCI suggested that hydrocarbons were a major component of the PM mass. Further studies were conducted on this multi-cylinder engine platform to characterize the PM emissions in more detail and understand the effect of a diesel oxidation catalyst (DOC) on the hydrocarbon-dominated PM emissions. Results from the study show that the DOC can effectively reduce the hydrocarbon emissions as well as the overall PM from RCCI combustion. The bimodal size distribution of PM from RCCI is altered by the DOC which reduces the smaller mode 10 nm size particles.

Author: Christopher P. Kolodziej
Publisher:
ISBN:
Category :
Languages : en
Pages : 310

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Author: Ajay Kumar Chaudhary
Publisher:
ISBN:
Category : Diesel motor
Languages : en
Pages : 398

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Author:
Publisher:
ISBN:
Category : Automobiles
Languages : en
Pages : 1218

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Author: National Research Council (U.S.). Diesel Impacts Study Committee. Technology Panel
Publisher: National Academies
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 390

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Author: Bartlesville Energy Research Center. Fuels Combustion Research Group
Publisher:
ISBN:
Category : Diesel motor exhaust gas
Languages : en
Pages : 246

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