Reduction of cold start emissions with microwave heated catalytic converters

Papetti, Viola; Eggenschwiler, Panayotis Dimopoulos; Schreiber, Daniel

doi:10.1007/978-3-658-25939-6_51

Cited by 2 publications

(3 citation statements)

References 4 publications

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“…Many studies have been published regarding modelling of pressure drop, mass transfer, and heat transfer in foams [4,14,15], and the respective knowledge can be incorporated in models for foam-substrate-based TWC applications. Another innovative technology that requires further modelling efforts is the introduction of an "artificial" supply of energy such as electrical heater or microwave heating source, able to heat up the catalytic converter and reduce cold starts [16].…”

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confidence: 99%

Analysis of TWC Characteristics in a Euro6 Gasoline Light Duty Vehicle

Papetti¹,

Eggenschwiler²,

Emmanouil³

et al. 2019

SAE Technical Paper Series

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Euro6 gasoline light duty vehicle has been tested at the engine dynamometer and the emissions have been analyzed upstream and downstream the Three-Way-Catalyst (TWC) during a WLTC cycle. Catalyst simulations have been used for assessing the processes inside the catalytic converter using a reaction scheme based on 19 brutto reactions (direct oxidation and reduction, selective catalytic reductions with CO, C 3 H 6 and H 2 , steam reforming, water-gas shift and bulk ceria as well as surface ceria reactions). The reactions have been parameterized in order to best approximate the measurements.Based on the reactions taken into account, the real vehicle emissions can be predicted with good accuracy. The simulations show that the cycle emissions comprise mainly the cold start contribution as well as discrete emission breakthrough events during transients. During cold start no reactions are evident in the catalyst before the temperature of the gas entering the catalyst reaches 270°C. Following the light-off, prevailing reactions are direct oxidation as well as surface ceria reactions for CO and THC. NO reduction during cold start is due to reaction with CO as well as due to surface ceria. During warm engine operation, CO breakthroughs during transients are mainly due to lack of oxygen following short periods where the engine lambda drops below one and most of surface and bulk CeO 2 has reacted to surface and bulk Ce 2 O 3 . Moreover in such incidents ceria is reacting with THC forming additional CO. THC breakthroughs during transients are mostly simultaneous with CO peaks and are also due to lack of oxygen and depleted CeO 2 . NO transient break-throughs occur when engine-out NO sharply increases, and the reactions with CO and ceria are not sufficient.Further analysis focused in highlighting the effects of variations of Lambda and precious metal content on reaction emissions and mechanisms.

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confidence: 99%

Analysis of TWC Characteristics in a Euro6 Gasoline Light Duty Vehicle

Papetti¹,

Eggenschwiler²,

Emmanouil³

et al. 2019

SAE Technical Paper Series

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“…There are the following heating measures to compare: 1) the possibility of additionally heating the exhaust gas before the entrance of the catalyst and 2) the possibility of additionally heating the catalyst (solid) itself. The former can happen with the help of an electrical resistance, such systems are already exiting in the market, and the latter can be introduced with microwaves, as proposed in [2]. Sure, a possibility is to use a combination of both measures.…”

Section: Evaluation Of Possible Cold Start Emission Mitigation Strate...mentioning

confidence: 99%

“…According to the emissions inventory program [1], cold start emissions of Euro 5 passenger cars amount to 68% of their total CO and 88% of HC emissions. Literally, modern engines emit during cold start the pollutant amount they would emit over more than 1'000km of warm operation [2]. Newest targeted measurements and simulations performed in our laboratory on a Euro 6 gasoline vehicle have shown that 17% of the CO, 91% of the THC and 66% of the NOx emissions during the WLTC cycle happen in the first 300s after the engine cold start (20°C).…”

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confidence: 95%

Heat Transfer Analysis of Catalytic Converters during Cold Starts

Papetti¹,

Eggenschwiler²,

Torre³

et al. 2019

SAE Technical Paper Series

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T he transient heat transfer behavior of an automotive catalytic converter has been simulated with OpenFOAM in 1D. The model takes into consideration the gas-solid convective heat transfer, axial wall conduction and heat capacity effects in the solid phase, but also the chemical reactions of CO oxidation, based on simplified Arrhenius and Langmuir-Hinshelwood approaches. The associated parameters are the results of data in literature tuned by experiments. Simplified cases of constant flow rates and gas temperatures in the catalyst inflow have been chosen for a comprehensive analysis of the heat and mass transfer phenomena. The impact of inlet flow temperatures and inlet flow rates on the heat up characteristics as well as in the CO emissions have been quantified. A dimensional analysis is proposed and dimensionless temperature difference and space-time coordinates are introduced. Using this suitably modified coordinates, for the case of negligible axial solid conduction, computed solid temperature at the reactor outlet lay on a typical S-curve, allowing the introduction of an analytical function. A series of variations in the inlet exhaust temperature and mass flow as well as the initial solid temperature was chosen in order to highlight relevant dependencies. Results show the performance of the catalyst during cold start and have been used for a preliminary energetic assessment of the effectiveness of preheating the catalyst, the exhaust gas or both.

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Reduction of cold start emissions with microwave heated catalytic converters

Cited by 2 publications

References 4 publications

Analysis of TWC Characteristics in a Euro6 Gasoline Light Duty Vehicle

Analysis of TWC Characteristics in a Euro6 Gasoline Light Duty Vehicle

Heat Transfer Analysis of Catalytic Converters during Cold Starts

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