In-line Hydrocarbon Adsorber for Cold Start Emissions - Part II

Noda, Naomi; Takahashi, Akira; Shibagaki, Yukinari; Mizuno, Hiroshige

doi:10.4271/980423

Cited by 19 publications

(8 citation statements)

References 5 publications

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“…For simulations with passive adsorption, we assumed that a 0.67 l adsorber device was installed midway between the 1.1 l TWC stages, as illustrated in Figure 6. The simulated adsorber device was also assumed to have the properties of a wash-coated cordierite monolith with a cell density of 400 cells/in 2 and a void fraction of 0.7. Based on the literature values, the storage capacities of HC and NO sorbents were assumed to be 1.5 mmol/g for C 3 H 6 29 and 0.80 mmol/g for NO 15 under dry conditions.…”

Section: Vehicle Simulations With Passive Adsorption After-treatmentmentioning

confidence: 99%

“…For current TWCs, this threshold is about 150–200 °C. 1,2 Recently, there has been considerable interest in developing catalysts that become active at lower temperatures. 3–5 Since a cold start always involves a delay in catalyst heat-up, there can be a significant release of carbon monoxide (CO), unburned hydrocarbons (HCs), and nitrogen oxides (NO x ) before the catalyst becomes functional.…”

Section: Introductionmentioning

confidence: 99%

“…In conventional vehicles, a cold start can contribute up to 80–90% of the total drive cycle emissions during the 30–40 s required to heat up the catalyst. 2,6 Thus a cold start is a major concern for HEVs and PHEVs, where engine operation is typically much more intermittent. This provides a major motivation for developing innovative technologies for reducing cold-start emissions from hybrid vehicles.…”

Section: Introductionmentioning

confidence: 99%

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Cold-start emissions control in hybrid vehicles equipped with a passive adsorber for hydrocarbons and nitrogen oxides

Gao

Kim

Choi

et al. 2012

Proceedings of the Institution of Mechanical Engineers, Part D:

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We present results from a computational study of the potential for using low-cost sorbent materials to trap the emissions of hydrocarbons and nitrogen oxides temporally during cold-start periods in hybrid electric vehicles and plug-in hybrid electric vehicles operating over transient driving cycles. The hydrocarbon adsorption behavior of a candidate sorbent composed of Ag-beta-zeolite was characterized in a laboratory flow reactor to estimate the kinetic parameters for a one-dimensional transient adsorber device model. This model was then implemented in the Powertrain Systems Analysis Toolkit to simulate a passive hydrocarbon adsorber device on a hybrid vehicle. The results indicate that such an adsorber can substantially reduce the hydrocarbon emissions by temporarily storing them until the three-way catalyst is sufficiently warm to remove them from the exhaust. A similar adsorber device model was simulated for nitrogen oxide control, using an initial set of conjectured kinetic parameters for transition metal oxides based on limited information in the literature. These latter simulations revealed the need to pursue additional experimental studies to characterize fully this class of sorbents. Such studies are especially relevant in the present context of rapidly evolving vehicle technology, because emission controls of this type do not involve any penalty in fuel consumption or require any change in engine operation.

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Section: Vehicle Simulations With Passive Adsorption After-treatmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cold-start emissions control in hybrid vehicles equipped with a passive adsorber for hydrocarbons and nitrogen oxides

Gao

Kim

Choi

et al. 2012

Proceedings of the Institution of Mechanical Engineers, Part D:

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show abstract

“…HC-traps [8], [9], [10] represent ideal, highly efficient, means for temporarily storing HC-emissions. However they have the disadvantage -still unresolved -that hydrocarbon desorption already begins at temperatures before the catalytic light-off temperature of oxidation-type or three-way catalytic converters is reached.…”

Section: Bypass Catalystsmentioning

confidence: 99%

The Necessity of Optimizing the Interactions of Advanced Post-Treatment Components in Order to Obtain Compliance with SULEV-Legislation

Brück¹,

Hirth²,

Maus³

1999

SAE Technical Paper Series

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Fleet tests conducted on electrical vehicles around the world have very clearly shown that battery-powered cars may be regarded as zero-emission vehicles with respect to their local environments only.Emission measurements on vehicles powered by internalcombustion engines equipped with optimized exhaustpost-treatment systems have indicated the prospects the latter offer for cleaning up the environment, i.e., for yielding negative emissions, when run at their normal operating temperatures. Replacing electric cars with SULEV's is thus a matter currently under discussion. This paper will cover the functions of the various individual components of such post-treatment systems, and will show that optimizing the interactions among those components will improve their catalytic efficiencies. 10.5 sec. SULEV

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“…1). Among the more successful methods that have been developed for shortening the warming-up period are: heating with electrical power [4], heating with an external combustion chamber [5], installing an auxiliary small-capacity catalytic converter [6], employing an adsorber between two catalysts with [7,8] or without a secondary air source [9] and using an on-board fuel reformer [10]. Although these methods are quite effective, their disadvantage is that they require an external energy source, a control unit or a three-stage catalyst.…”

Section: Introductionmentioning

confidence: 99%

Reducing cold-start emission from internal combustion engines by means of a catalytic converter embedded in a phase-change material

Korin

Reshef

Tshernichovesky

et al. 1999

Proceedings of the Institution of Mechanical Engineers, Part D:

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Under normal operating conditions, catalytic converters appear to be the most effective means of reducing air pollution from internal combustion (IC) engines. The conversion efficiency, however, declines very steeply for temperatures below about 350°C and is practically zero during the starting and warming-up period. Improving the conversion efficiency under these conditions is important, particularly in large cities, where the number of startings per vehicle per day tends to be high. Among the more successful solutions are preheating of the catalyst electrically, warming up of the catalyst in an external combustion chamber, installation of an auxiliary small-capacity catalytic converter, and employment of an adsorbing unit between two catalysts. Although these methods are quite effective, their disadvantage lies in the fact that they require an external energy source, an additional component (a control unit) or a three-stage catalyst. In the present work an investigation was made of a solution based on the exploitation of thermal capacitance to keep the catalyst temperature high during off-operation periods. A phase-change material (PCM) with a transition temperature of 352.7°C, which is slightly above the light-off temperature of the metallic catalyst, was specially formulated, and a system comprising a catalytic converter embedded in the PCM was designed and tested. Under normal engine operating conditions, some of the thermal energy of the exhaust gases was stored in the PCM. During the time that the vehicle was not in use, the PCM underwent partial solidification, and the latent heat thus produced was exploited to maintain the catalyst temperature within the desired temperature range for maximum conversion efficiency.

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In-line Hydrocarbon Adsorber for Cold Start Emissions - Part II

Cited by 19 publications

References 5 publications

Cold-start emissions control in hybrid vehicles equipped with a passive adsorber for hydrocarbons and nitrogen oxides

Cold-start emissions control in hybrid vehicles equipped with a passive adsorber for hydrocarbons and nitrogen oxides

The Necessity of Optimizing the Interactions of Advanced Post-Treatment Components in Order to Obtain Compliance with SULEV-Legislation

Reducing cold-start emission from internal combustion engines by means of a catalytic converter embedded in a phase-change material

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