Cold-Start Hydrocarbon Collection for Advanced Exhaust Emission Control

Heimrich, Martin J.; Smith, Lawrence R.; Kitowski, Jack

doi:10.4271/920847

Cited by 34 publications

(2 citation statements)

References 6 publications

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“…Zeolites have received the majority of the attention for this application due to their properties as molecular sieves, hydrothermal stability, and solid acid behavior [4][5][6][7][8][9][10][11]. For diesel exhaust applications, zeolite beta (BEA) is often studied.…”

Section: Introductionmentioning

confidence: 99%

Effects of CO and H2O Co-Feed on the Adsorption and Oxidation Properties of a Pd/BEA Hydrocarbon Trap

Zelinsky

Epling

2021

Catalysts

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Hydrocarbon traps for exhaust emissions control adsorb hydrocarbons in low temperature exhaust and release them as the exhaust warms up. In this work, a Pd/BEA hydrocarbon trap was tested under lean exhaust conditions using ethylene and dodecane as model hydrocarbons. Ethylene uptake was partially inhibited by CO and H2O when fed separately. When both were added, the loss in ethylene uptake was 90% relative to the condition with no H2O or CO. Dodecane uptake was unchanged under all conditions tested. During a temperature ramp, ethylene desorbed and was combusted to CO2 and H2O over active Pd centers. Further, oxidation light-off of dodecane generated an exotherm which caused rapid desorption of the remaining hydrocarbon species from the zeolite. For both hydrocarbons, CO co-feed led to a decreased oxidation light-off temperature, and therefore lower desorption temperature. By pretreating the catalyst in CO and H2O at 80 °C, and even after removing CO from the feed, the enhanced oxidation light-off behavior was observed. DRIFTS characterization shows that some form of oxidized Pd was reducible to Pd0 by CO at 80 °C only in the presence of H2O. Further, this reduction appears reversible by high temperature oxygen treatment. We speculate that this reduced Pd phase serves as the active site for low temperature hydrocarbon oxidation.

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Section: Introductionmentioning

confidence: 99%

Effects of CO and H2O Co-Feed on the Adsorption and Oxidation Properties of a Pd/BEA Hydrocarbon Trap

Zelinsky

Epling

2021

Catalysts

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“…Heimrich et al [11] incorporated a zeolite molecular sieve in the exhaust system to adsorb cold-start emissions. Their results showed a 35 per cent reduction in hydrocarbon emissions.…”

Section: Introductionmentioning

confidence: 99%

A study to investigate the capability of adsorbents for reduction of cold-start emissions

Miller

Ginter

Seaba

et al. 1998

Proceedings of the Institution of Mechanical Engineers, Part D:

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Most of the emissions (about 60 per cent) from automobiles occur during a cold start before the catalytic converter becomes active. The use of an adsorbent trap for temporary storage of emitted hydrocarbons before catalysts attain the light-off temperature in the converter has been investigated as a means for reduction of cold-start emissions. The hydrocarbon emissions can be reduced significantly if the hydrocarbons are retained by the trap until catalysts reach the light-off temperature. The effect of engine speed on the emission of NO x , CO and hydrocarbons and their subsequent retention in the adsorption trap was studied. A hydrophobic adsorbent, Hisiv-1000, and molecular sieve 13X were used individually and in conjunction in the trap to adsorb hydrocarbons. Although significant amounts of hydrocarbons were adsorbed in the trap initially, they were released from the trap rather quickly even before catalysts reached the light-off temperature.

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Exhaust Control, Automotive

Mooney¹

2000

Kirk-Othmer Encyclopedia of Chemical Technology

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Automotive exhaust gas composition depends on the fuel, the air‐fuel ratio, and on engine type, wear, temperature, etc. Exhaust control systems must be versatile enough to oxidize unburned fuel and partial oxidation products such as carbon monoxide, yet reduce nitrogen oxides, at both engine start‐up and during sustained engine operation. Emission control systems consist of a catalytic converter for the oxidation‐reduction of exhaust gases in conjunction with a fuel ignition system and oxygen sensor to regulate the air‐fuel ratio. Exhaust for both gasoline and alternative fuels is discussed.

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Cold-Start Hydrocarbon Collection for Advanced Exhaust Emission Control

Cited by 34 publications

References 6 publications

Effects of CO and H2O Co-Feed on the Adsorption and Oxidation Properties of a Pd/BEA Hydrocarbon Trap

Effects of CO and H2O Co-Feed on the Adsorption and Oxidation Properties of a Pd/BEA Hydrocarbon Trap

A study to investigate the capability of adsorbents for reduction of cold-start emissions

Exhaust Control, Automotive

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