Diesel Emissions and Their Control

Khair, Magdi; Majewski, Wiesław

doi:10.4271/r-303

Cited by 75 publications

(30 citation statements)

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“…Figure 1a shows typical composition of exhaust gas from diesel engine. CO 2 and pollutant emissions are about 12 and 1% (CO, HC, NO x , SO 2 , PM), respectively (Majewski and Khair, 2006). Figure 1b presents emission standard of European Union for heavy duty vehicles (Delphi, 2012), NO accounts for 90% of total NOx emissions, with the remainder being NO 2 (Hebbar, 2014).…”

Section: Introductionmentioning

confidence: 99%

Carbon Dioxide Capture From Internal Combustion Engine Exhaust Using Temperature Swing Adsorption

Sharma

Maréchal

2019

Front. Energy Res.

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In order to reduce the CO 2 emissions in the transportation sector, one can electrify the vehicle, switch to biofuel, or capture and store CO 2 on board. In this study, integration of an on board CO 2 capture and storage unit with an internal combustion engine has been proposed. The technology can be applied for various internal combustion or Stirling engines with targeted applications in the transportation sector. Truck transport for goods delivery is used as an example for on board CO 2 capture and storage system design. The investigated system integrates a temperature swing adsorption system for CO 2 capture with a turbo-compressor system to compress and liquefy the captured CO 2 using the waste heat of the exhaust gases of the engine. Energy and exergy analyses of the proposed CO 2 captured system are studied in details. The CO 2 capture system for engine exhaust stream (car, truck, bus, ship, or train) can capture 90% of the emitted CO 2 , without any energy penalty. This system can be integrated into overall mobility system (fuel-engine-CO 2-fuel), where captured CO 2 can be recycled as conventional liquid or gaseous fuels produced from renewable energy sources.

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Section: Introductionmentioning

confidence: 99%

Carbon Dioxide Capture From Internal Combustion Engine Exhaust Using Temperature Swing Adsorption

Sharma

Maréchal

2019

Front. Energy Res.

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“…It produces engineout emissions of nitrous oxides and particulate matter (PM) that need after treatment to match the extremely low limits set up for transport applications (Lloyd and Cackette, 2001;Burtscher, 2005;Maricq, 2007), despite air quality is not only influenced by the transport emissions but by many other sources. Combustion strategies alone (Khair and Majewski, 2006) were not enough to meet the emission threshold, and specific lean burn catalysts were needed especially for NOx additional to particulate filters in the exhaust. Despite their economic success, diesel engines were facing ever more stringent emission legislation worldwide (Knecht, 2008;Zhao, 2009) at the price of phasing out the technology targeting unrealistic minimal incremental improvements.…”

Section: Introductionmentioning

confidence: 99%

Advantages and Disadvantages of Diesel Single and Dual-Fuel Engines

Boretti

2019

Front. Mech. Eng.

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The pros and the cons of lean-burn, compression ignition (CI), direct injection (DI) internal combustion engines (ICE) are reviewed for transport applications. Fueling options considered include diesel only and dual-fuel applications with diesel and a gaseous fuel (CNG, LNG, and LPG). CIDI ICEs have higher fuel conversion efficiencies than stoichiometric, spark ignition (SI) ICEs, whether DI or port fuel injected (PFI). However, diesel-fueled CIDI ICEs have higher particulate matter (PM) and NOx engine-out emissions. The tail-pipe NOx emissions in real-world driving of diesel-powered vehicles have been, in the past, above the limits requested over the simplified cold start driving cycles used for certification. This issue has recently been resolved. The newest diesel-powered vehicles are now compliant with new laboratory test cycles and real-world-driving schedules and have no disadvantages in terms of criteria air pollutants compared to older diesel vehicles, while delivering improvements in fuel economy and CO 2 emissions. Dual-fuel CIDI ICEs offer the opportunity for enhanced environmental friendliness. Dual-fuel CIDI ICEs have lower engine-out NOx and PM emissions compared to diesel-only CIDI ICEs. The latest diesel-only vehicles and vehicles with dual-fuel ICEs deliver dramatic reductions in tail-pipe PM emissions compared to older diesel-only vehicles. Moreover, they deliver tail-pipe PM emissions well below the ambient conditions in most city areas that are highly polluted, thereby helping to clean the air. The diesel-fueled CIDI ICEs may be further improved to deliver better fuel economy and further reduced tail-pipe emissions. The dual-fuel CIDI ICE has more room for improvement to produce similar or better steady state and transient performance in terms of torque, power output and fuel conversion efficiency compared to diesel-fueled CIDI ICEs, while drastically reducing CO 2 and PM tail-pipe emissions, and improving NOx tail-pipe emissions. This is due to the ability to modulate the premixed and diffusion phases of combustion with a second fuel that is much easier to vaporize and is less prone to auto-ignition. Further development of the fuel injection system for the second fuel will lead to novel dual-fuel CIDI ICE designs with better performance.

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“…In order to improve the health of the population and decrease the rate of climate change, abatement of toxic and environmentally harsh nitric oxides from the vehicle exhaust is critical [1]. The selective catalytic reduction (SCR) technology achieves this.…”

Section: Introductionmentioning

confidence: 99%

Palladium/ Zeolite Low Temperature Passive NOx Adsorbers (PNA): Structure-Adsorption Property Relationships for Hydrothermally Aged PNA Materials

Khivantsev

Jaegers²,

Kovařík³

et al. 2019

Preprint

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Zeolites with different framework structures (SSZ-13, ZSM-5, BEA) but similar Si/Al ratios and Pd loading (~1 wt%) were synthesized and evaluated as low temperature passive NOx adsorbers (PNA). These materials exhibit high NOx adsorption efficiency with atomically dispersed Pd the active adsorption site. Hydrothermal aging at 750 ºC for 16 hours in the presence of 10% water vapor in air resulted in the formation of PdO nanoparticles in all three samples as evidenced by high energy XRD. Hydrothermal aging of the small-pore Pd/SSZ-13 (Si/Al = 6), which contain ~100-90% atomically dispersed palladium ions, decreases its PNA performance only by ~10-20%, indicating agglomeration of only ~10-20% of all atomically dispersed Pd into PdO. High-field solid state 27Al NMR studies on the fresh and aged samples substantiate dealumination and significant changes in the distribution of Al (and thus, Brönsted acid) sites after hydrothermal aging. FTIR measurements with NO probe molecule and titration of Brönsted acid sites with nitrosyl (NO+) ions further corroborate the 27Al NMR data. Because framework aluminum atoms are the anchoring sites for atomically dispersed Pd ions, their elution from the framework causes the loss of active atomically dispersed Pd species. With the aid of HAADF-STEM imaging and synchrotron XRD studies, we further confirm and visualize the fate of these Pd species – they agglomerate into PdO nanoparticles on the external surface of zeolite. Consequently, these changes lead to the decrease in PNA performance of these materials after hydrothermal aging. The thus formed agglomerates cannot be re-dispersed back to their ionic state due to the loss of framework Al T-sites and/or inherent stability of such large PdO particles. Our study demonstrates that, unlike in previous studies that found increased PNA performance upon HTA, high temperatures hydrothermal aging of PNA materials, that contain atomically dispersed Pd initially, results in a decrease in NOx storage efficiency due to the formation of PdO agglomerates. However, we also highlight the high hydrothermal stability of predominantly atomically dispersed 1-3 wt% Pd/SSZ-13 (Si/Al = 6), whose performance decreases only marginally after prolonged hydrothermal aging at 750 ºC. This study shows that hydrothermally stable passive NOx materials can be prepared using small-pore SSZ-13 zeolite.

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Diesel Emissions and Their Control

Cited by 75 publications

References 0 publications

Carbon Dioxide Capture From Internal Combustion Engine Exhaust Using Temperature Swing Adsorption

Carbon Dioxide Capture From Internal Combustion Engine Exhaust Using Temperature Swing Adsorption

Advantages and Disadvantages of Diesel Single and Dual-Fuel Engines

Palladium/ Zeolite Low Temperature Passive NOx Adsorbers (PNA): Structure-Adsorption Property Relationships for Hydrothermally Aged PNA Materials

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