Review of thermal management of catalytic converters to decrease engine emissions during cold start and warm up

Gao, Jianbing; Tian, Gui Yun; Sorniotti, Aldo; Karci, Ahu Ece Hartavi; Palo, Raffaele Di

doi:10.1016/j.applthermaleng.2018.10.037

Cited by 204 publications

(104 citation statements)

References 84 publications

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“…It is estimated that by 2020 China's car ownership will reach 280 million vehicles, which could make China the largest country in terms of car ownership. Besides, the challenges facing gasoline vehicles have become even more acute [3,4], making the development of new energy vehicles crucial, especially, after the implementation of the new CO 2 emission limit, which will make the demand for new energy sources more urgent.…”

Section: Introductionmentioning

confidence: 99%

A Numerical Investigation on De-NOx Technology and Abnormal Combustion Control for a Hydrogen Engine with EGR System

et al. 2020

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The combustion emissions of the hydrogen-fueled engines are very clean, but the problems of abnormal combustion and high NOx emissions limit their applications. Nowadays hydrogen engines use exhaust gas recirculation (EGR) technology to control the intensity of premixed combustion and reduce the NOx emissions. This study aims at improving the abnormal combustion and decreasing the NOx emissions of the hydrogen engine by applying a three-dimensional (3D) computational fluid dynamics (CFD) model of a single-cylinder hydrogen-fueled engine equipped with an EGR system. The results indicated that peak in-cylinder pressure continuously increased with the increase of the ignition advance angle and was closer to the top dead center (TDC). In addition, the mixture was burned violently near the theoretical air–fuel ratio, and the combustion duration was shortened. Moreover, the NOx emissions, the average pressure, and the in-cylinder temperature decreased as the EGR ratio increased. Furthermore, increasing the EGR ratio led to an increase in the combustion duration and a decrease in the peak heat release rate. EGR system could delay the spontaneous combustion reaction of the end-gas and reduce the probability of knocking. The pressure rise rate was controlled and the in-cylinder hot spots were reduced by the EGR system, which could suppress the occurrence of the pre-ignition in the hydrogen engine.

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Section: Introductionmentioning

confidence: 99%

A Numerical Investigation on De-NOx Technology and Abnormal Combustion Control for a Hydrogen Engine with EGR System

et al. 2020

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“…However, both the power balancing services and the demand-driven operation lead to more frequent start-ups of the plant and thus to an increasing number of cold-start processes. Research in the automotive sector has widely shown that cold-start procedures cause a high share of the total pollutant emissions of a system with an internal combustion engine (ICE) [10][11][12][13][14]. As mini and micro CHPs (mCHP) generally feature low pollutant emissions under steady-state conditions, an increasing number of cold-starts would mitigate this property to a great extent.…”

Section: Introductionmentioning

confidence: 99%

Reduction of Cold-Start Emissions for a Micro Combined Heat and Power Plant

et al. 2020

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Decentralized power generation by combined heat and power plants becomes increasingly popular as a measure to advance the energy transition. In this context, a substantial advantage of small combined heat and power plants is based on the relatively low pollutant emissions. However, a large proportion of the pollutant emissions is produced during a cold-start. This fact is not reflected in governmental and institutional emission guidelines, as these strongly focus on the emission levels under steady-state conditions. This study analyzes the spark advance, the reference air/fuel ratio and an electrically heated catalyst in terms of their potential to reduce the cold-start emissions of a micro combined heat and power plant which uses a natural gas fueled reciprocating internal combustion engine as prime mover and a three-way catalytic converter as aftertreatment system. Based on these measures, control approaches were developed that account for the specific operating conditions of the class of small combined heat and power plants, e.g., full-load operation and flexible, demand-driven runtimes. The experimental data demonstrates that even solutions with marginal adaptation/integration effort can reduce cold-start emissions to a great extent.

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“…Stringent emission regulations were put in action and became the main drive for advanced engine technologies, such as partially premixed compression ignition (PPCI), partially premixed combustion (PPC), high pressure fuel injection, split injection, advanced control, diesel oxidation catalysts (DOCs), diesel particulate filters (DPFs), selective catalyst reduction (SCR), nonthermal plasma (NTP) systems, and adoption of biodiesel . Nevertheless, the challenge of high exhaust emissions during engine cold start and warm‐up still remains, which is caused by the low cylinder and exhaust temperatures, resulting in poor catalyst efficiency . Iodice et al measured the exhaust emissions from the internal combustion engine in the warm‐up phase of the considered driving cycle during chassis‐dynamometer tests.…”

Section: Introductionmentioning

confidence: 99%

“…In general, catalyst light‐off time and fuel penalty have a trade‐off relationship. Furthermore, also the engine power output may be affected . To maintain the catalyst temperature after the engine is switched off, thus reducing the light‐off time when the engine is restarted, investigations were carried out to integrate the catalytic converts into heat storage devices including phase changing materials, which recycle the exhaust waste heat .…”

Section: Introductionmentioning

confidence: 99%

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On the emission reduction through the application of an electrically heated catalyst to a diesel vehicle

Gao

Tian

Sorniotti

2019

Energy Science & Engineering

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Exhaust emissions from diesel engine powered vehicles are considerably high during cold start and warm‐up, because of the poor catalyst performance due to the insufficient catalyst temperature. The controlled heat injection allowed by electrically heated catalysts can effectively reduce the catalyst light‐off time with relatively moderate fuel penalty. This paper compares the exhaust temperature and emissions of a case study diesel vehicle in cold and warm start conditions, and proposes two electrically heated catalyst control strategies, which are evaluated in terms of emission reduction and energy consumption with different target temperature settings. In addition, a new performance indicator, that is, the specific emission reduction, is used to evaluate the after‐treatment system and associated thermal management. For the worldwide harmonized light vehicle test cycle, the results without electrically heated catalyst show that from both cold and warm start conditions a large amount of operating points of the engine is located in the region of partial catalyst light off. Moreover, emissions, especially in terms of carbon monoxide and hydrocarbon, significantly decrease with the electrically heated catalyst implementation, for example, by at least 50% from cold start; however, they still tend to be rather substantial when the fuel is re‐injected after the engine cutoff phases. The exhaust temperature is lower than the target values in the sections of the driving cycle in which the electrically heated catalyst power is saturated according to the maximum level allowed by the device. The carbon dioxide penalty brought by the electrically heated catalyst ranges from 3.93% to 6.65% and from 6.49% to 9.35% for warm and cold start conditions, respectively.

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Review of thermal management of catalytic converters to decrease engine emissions during cold start and warm up

Cited by 204 publications

References 84 publications

A Numerical Investigation on De-NOx Technology and Abnormal Combustion Control for a Hydrogen Engine with EGR System

A Numerical Investigation on De-NOx Technology and Abnormal Combustion Control for a Hydrogen Engine with EGR System

Reduction of Cold-Start Emissions for a Micro Combined Heat and Power Plant

On the emission reduction through the application of an electrically heated catalyst to a diesel vehicle

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