Cold Start Effect Phenomena over Zeolite SCR Catalysts for Exhaust Gas Aftertreatment

2013 ◽  
Vol 6 (1) ◽  
pp. 190-199 ◽  
Author(s):  
Volker Schmeisser ◽  
Michel Weibel ◽  
Laura Sebastian Hernando ◽  
Isabella Nova ◽  
Enrico Tronconi ◽  
...  
Keyword(s):  
Cold Start ◽  
Exhaust Gas ◽  
Exhaust Gas Aftertreatment ◽  
Scr Catalysts

Mathematical modelling of cold start effects over zeolite SCR catalysts for exhaust gas aftertreatment

2014 ◽  
Vol 231 ◽  
pp. 99-104 ◽  
Author(s):  
Massimo Colombo ◽  
Isabella Nova ◽  
Enrico Tronconi ◽  
Volker Schmeiβer ◽  
Michel Weibel
Keyword(s):  
Mathematical Modelling ◽  
Cold Start ◽  
Exhaust Gas ◽  
Exhaust Gas Aftertreatment ◽  
Scr Catalysts

Design of a Flow Reactor for Testing Multi-Brick Catalyst Systems Using Rapid Exhaust Gas Composition Switches

2009 ◽  
Author(s):  
Stefan Klinkert ◽  
John W. Hoard ◽  
Sakthish R. Sathasivam ◽  
Dennis N. Assanis ◽  
Stanislav V. Bohac
Keyword(s):  
Flow Reactor ◽  
Combustion Engine ◽  
Synergistic Effects ◽  
Control Program ◽  
Exhaust Gas ◽  
Gas Composition ◽  
Lean Burn ◽  
Exhaust Gas Aftertreatment ◽  
Scr Catalysts ◽  
Catalyst Systems

In recent years, diesel exhaust gas aftertreatment has become a core combustion engine research subject because of both increasingly stringent emission regulations and incentives toward more fuel-efficient propulsion systems. Lean NOX traps (LNT) and selective catalytic reduction (SCR) catalysts represent two viable pathways for the challenging part of exhaust gas aftertreatment of lean burn engines: NOX abatement. It has been found that the combination of LNT and SCR catalysts can yield synergistic effects. Switches in the operation mode of the engine, temporarily enriching the mixture, are required to regenerate the LNT catalyst and produce ammonia for the SCR. This paper describes the design of a catalyst flow reactor that allows studying multi-brick catalyst systems using rapid exhaust gas composition switches and its initial validation. The flow reactor was designed primarily to study the potential of combining different aftertreatment components. It can accommodate two sample bricks at a time in two tube furnaces, which allows for independent temperature control. Moreover, the flow reactor allows for very flexible control of the composition and flow rate of the synthetic exhaust, which is blended using mass flow controllers. By using a two-branch design, very fast switches between two exhaust gas streams, as seen during the regeneration process of a LNT catalyst, are possible. The flow reactor utilizes a variety of gas analyzers, including a 5-Hz FTIR spectrometer, an emissions bench for oxygen and THC, a hydrogen mass spectrometer, and gas chromatographs for HC speciation. An in-house control program allows for data recording, flow reactor control, and highly flexible automation. Additionally, the hardware and software incorporate features to ensure safe testing. The design also has provisions for engine exhaust sampling.

scholarly journals The influence of high efficiency engines and hybrids on exhaust systems

2017 ◽  
Vol 171 (4) ◽  
pp. 207-210
Author(s):  
Matthias WEBER
Keyword(s):  
High Efficiency ◽  
New Technologies ◽  
Combustion Process ◽  
Gaseous Ammonia ◽  
Exhaust Gas ◽  
Exhaust Gas Aftertreatment ◽  
Conversion Rates ◽  
Scr Catalysts ◽  
Exhaust Line ◽  
Soot Loading

Increased efficiency of the combustion process itself and low losses in the Engine, lead to lower temperatures in the exhaust line. Combined with the exhaust gas energy recovery as well as the hybridization of the drivetrain, this temperature decrease will require additional efforts for the exhaust gas aftertreatment in future. Current technologies like SCR with urea could only be used in future with additional heating elements or will need to change to different catalysts or gaseous Ammonia, to keep the current efficiency and conversion rates. Catalyst and filter elements with ultra-low backpressure creating additional new challenges for the correct and robust diagnostics of these aftertreatment components and all emission relevant parts and thresholds. New technologies are needed like the direct measurement of the DPF soot loading with radio frequencies or NH3 sensors to precisely control the ammonia slip for high conversion rates of SCR catalysts.

Prospects for the use of dry carbamide in diesel exhaust gas aftertreatment systems

2019 ◽  
pp. 3-14
Author(s):  
V.N. Kaminskij ◽  
◽  
G.G. Nadarejshvili ◽  
V.I. Panchishnyj ◽  
R.M. Zagredinov ◽  
...  
Keyword(s):  
Diesel Exhaust ◽  
Exhaust Gas ◽  
Exhaust Gas Aftertreatment ◽  
Aftertreatment Systems

Next Generation Diesel Engine Potential of Highly Integrated Exhaust Gas Aftertreatment

MTZ worldwide ◽  
2017 ◽  
Vol 78 (9) ◽  
pp. 42-47
Author(s):  
Matthias Diezemann ◽  
Christopher Severin ◽  
Maximilian Brauer ◽  
Frank Bunar
Keyword(s):  
Diesel Engine ◽  
Exhaust Gas ◽  
Next Generation ◽  
Exhaust Gas Aftertreatment

Exhaust Gas Aftertreatment of the Future

MTZ worldwide ◽  
2018 ◽  
Vol 79 (7-8) ◽  
pp. 70-75
Author(s):  
Uwe Gärtner ◽  
Hans-Peter Rabl ◽  
Uwe Zink
Keyword(s):  
Exhaust Gas ◽  
Exhaust Gas Aftertreatment ◽  
The Future

Influence of Low Ambient Temperatures on the Exhaust Gas and Deposit Composition of Gasoline Engines

2021 ◽  
pp. 1-11
Author(s):  
Dominik Appel ◽  
Fabian P. Hagen ◽  
Uwe Wagner ◽  
Thomas Koch ◽  
Henning Bockhorn ◽  
...  
Keyword(s):  
Internal Combustion Engines ◽  
Gasoline Engine ◽  
Cold Start ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Ex Situ ◽  
Exhaust Gas ◽  
Gasoline Engines ◽  
Ambient Temperatures ◽  
Aftertreatment Systems

Abstract To comply with future emission regulations for internal combustion engines, system-related cold-start conditions in short-distance traffic constitute a particular challenge. Under these conditions, pollutant emissions are seriously increased due to internal engine effects and unfavorable operating conditions of the exhaust aftertreatment systems. As a secondary effect, the composition of the exhaust gases has a considerable influence on the deposition of aerosols via different deposition mechanisms and on fouling processes of exhaust gas-carrying components. Also, the performance of exhaust gas aftertreatment systems may be affected disadvantageously. In this study, the exhaust gas and deposit composition of a turbocharged three-cylinder gasoline engine is examined in-situ upstream of the catalytic converter at ambient and engine starting temperatures of -22 °C to 23 °C using a Fourier-transform infrared spectrometer and a particle spectrometer. For the cold start investigation, a modern gasoline engine with series engine periphery is used. In particular, the investigation of the behavior of deposits in the exhaust system of gasoline engines during cold start under dynamic driving conditions represents an extraordinary challenge due to an average lower soot concentration in the exhaust gas compared to diesel engines and so far, has not been examined in this form. A novel sampling method allows ex-situ analysis of formed deposits during a single driving cycle. Both, particle number concentration and the deposition rate are higher in the testing procedure of Real Driving Emissions (RDE) than in the inner-city part of the Worldwide harmonized Light vehicles Test Cycle (WLTC). In addition, reduced ambient temperatures increase the amount of deposits, which consist predominantly of soot and to a minor fraction of volatile compounds. Although the primary particle size distributions of the deposited soot particles do not change when boundary conditions change, the degree of graphitization within the particles increases with increasing exhaust gas temperature.

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