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.

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.

Combustion process and exhaust gas aftertreatment in the Mercedes-Benz Bluetec concept

MTZ worldwide ◽  
2007 ◽  
Vol 68 (6) ◽  
pp. 2-5 ◽  
Author(s):  
Hermann Breitbach ◽  
Joachim Schommers ◽  
Ralf Binz ◽  
Bernd Lindemann ◽  
Andreas Lingens ◽  
...  
Keyword(s):  
Combustion Process ◽  
Exhaust Gas ◽  
Exhaust Gas Aftertreatment

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

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

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

scholarly journals Research on the Operating Characteristics of Hydraulic Free-Piston Engines: A Systematic Review and Meta-Analysis

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3530
Author(s):  
Fukang Ma ◽  
Shuanlu Zhang ◽  
Zhenfeng Zhao ◽  
Yifang Wang
Keyword(s):  
Systematic Review ◽  
High Efficiency ◽  
Meta Analysis ◽  
Combustion Process ◽  
Research Progress ◽  
Future Research ◽  
Operating Characteristics ◽  
Piston Engine ◽  
Free Piston ◽  
Free Piston Engine

The hydraulic free-piston engine (HFPE) is a kind of hybrid-powered machine which combines the reciprocating piston-type internal combustion engine and the plunger pump as a whole. In recent years, the HFPE has been investigated by a number of research groups worldwide due to its potential advantages of high efficiency, energy savings, reduced emissions and multi-fuel operation. Therefore, our study aimed to assess the operating characteristics, core questions and research progress of HFPEs via a systematic review and meta-analysis. We included operational control, starting characteristics, misfire characteristics, in-cylinder working processes and operating stability. We conducted the literature search using electronic databases. The research on HFPEs has mainly concentrated on four kinds of free-piston engine, according to piston arrangement form: single piston, dual pistons, opposed pistons and four-cylinder complex configuration. HFPE research in China is mainly conducted in Zhejiang University, Tianjin University, Jilin University and the Beijing Institute of Technology. In addition, in China, research has mainly focused on the in-cylinder combustion process while a piston is free by considering in-cylinder combustion machinery and piston dynamics. Regarding future research, it is very important that we solve the instabilities brought about by chance fluctuations in the combustion process, which will involve the hydraulic system’s efficiency, the cyclical variation, the method of predicting instability and the recovery after instability.

scholarly journals The Synergy of Two Biofuel Additives on Combustion Process to Simultaneously Reduce NOx and PM Emissions

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2784
Author(s):  
Jerzy Cisek ◽  
Szymon Lesniak ◽  
Winicjusz Stanik ◽  
Włodzimierz Przybylski
Keyword(s):  
Heat Release ◽  
Combustion Rate ◽  
Combustion Process ◽  
The Other ◽  
Fuel Additive ◽  
Exhaust Gas ◽  
Synergy Effect ◽  
Engine Exhaust ◽  
Other Hand ◽  
Heat Released

The article presents the results of research on the influence of two fuel additives that selectively affect the combustion process in a diesel engine cylinder. The addition of NitrON® reduces the concentration of nitrogen oxides (NOx), due to a reduction in the kinetic combustion rate, at the cost of a slight increase in the concentration of particulate matter (PM) in the engine exhaust gas. The Reduxco® additive reduces PM emissions by increasing the diffusion combustion rate, while slightly increasing the NOx concentration in the engine exhaust gas. Research conducted by the authors confirmed that the simultaneous use of both of these additives in the fuel not only reduced both NOx and PM emissions in the exhaust gas but additionally the reduction of NOx and PM emissions was greater than the sum of the effects of these additives—the synergy effect. Findings indicated that the waveforms of the heat release rate (dQ/dα) responsible for the emission of NOx and PM in the exhaust gas differed for the four tested fuels in relation to the maximum value (selectively and independently in the kinetic and diffusion stage), and they were also phase shifted. Due to this, the heat release process Q(α) was characterized by a lower amount of heat released in the kinetic phase compared to fuel with NitrON® only and a greater amount of heat released in the diffusion phase compared to fuel with Reduxco® alone, which explained the lowest NOx and PM emissions in the exhaust gas at that time. For example for the NOx concentration in the engine exhaust: the Nitrocet® fuel additive (in the used amount of 1500 ppm) reduces the NOx concentration in the exhaust gas by 18% compared to the base fuel. The addition of a Reduxco® catalyst to the fuel (1500 ppm) unfortunately increases the NOx concentration by up to 20%. On the other hand, the combustion of the complete tested fuel, containing both additives simultaneously, is characterized, thanks to the synergy effect, by the lowest NOx concentration (reduction by 22% in relation to the base). For example for PM emissions: the Nitrocet® fuel additive does not significantly affect the PM emissions in the engine exhaust (up to a few per cent compared to the base fuel). The addition of a Reduxco® catalyst to the fuel greatly reduces PM emissions in the engine exhaust, up to 35% compared to the base fuel. On the other hand, the combustion of the complete tested fuel containing both additives simultaneously is characterized by the synergy effect with the lowest PM emission (reduction of 39% compared to the base fuel).

Nanomaterials combine multiple therapeutic approaches for cancer cell multidrug resistance, ferroptotic cell death is promising in various cancers

2021 ◽  
Author(s):  
Moataz Dowaidar
Keyword(s):  
Cell Death ◽  
Multidrug Resistance ◽  
Cancer Cell ◽  
High Efficiency ◽  
New Technologies ◽  
Multidrug Resistant ◽  
Therapeutic Approaches ◽  
Combination Strategies ◽  
New Strategy ◽  
Chemotherapy Patients

Cancer cell multidrug resistance (MDR) is one of the most significant barriers to chemotherapy patients' ability to treat malignant tumors.This review first discusses the basic processes of MDR and then details the newest usage of nanomaterials combining multiple therapeutic approaches (e.g. PDT, PTT, gas therapy, gene therapy, and CDT) with MDR chemotherapy. We also analyze the advantages and rationales of these combination systems and why they can reduce MDR cancer cells. Currently, together with various new treatment approaches, MDR-related chemotherapeutic research is gaining momentum in search of better therapeutic results. PDT, for example, has the ability to eliminate high-efficiency multidrug-resistant malignancies but has limited relevance to tumor treatment. In this perspective, SDT is a highly promising approach as it increases ROS production utilizing ultrasonic vibrations, allowing magnitude orders to reach deeper than light. PTT is also often criticized for NIR light's restricted penetration depth; thermomagnetic therapy, using magnetic fields to produce local tissue hyperthermia, can considerably alleviate this problem. However, current research on the possibilities of using these new technologies to fight MDR remains rather rare, and more combination strategies should be carefully investigated in the future. Moreover, ongoing discoveries of cell death pathways, highlighted by recent ferroptosis findings, present a new strategy for our battle against MDR and may revolutionize our knowledge of MDR formation. Ferroptotic cell death promises to treat MDR in various cancers. While most of this cutting-edge research is still in its infancy, we anticipate gaining a deeper understanding of the effectiveness of these revolutionary anti-MDR medicines in the near future.

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