1,721,052 research outputs found
Numerical Evaluation of a New Strategy of Emissions Reduction by Urea Direct Injection for Heavy Duty Diesel Engines
Full text linkThe effect of ammoniac deoxidizing agent (Urea) on the reduction of NOx produced in the Diesel engine was investigated numerically. Urea dissolved in water was directly injected into the engine cylinder during the expansion stroke. The NOx deoxidizing process was described using a simplified chemical kinetic model coupled with the comprehensive kinetics of Diesel oil surrogate combustion. If the technology of DWI (Direct Water Injection) with the later injection timing was used, the deoxidizing reactants could be delivered in a controlled amount directly into the flame plume zones, where NOx formed. Numerical simulations for the Isotta Fraschini DI Diesel engine were carried out using the KIVA-3V code, modified to account for the “co-fuel” injection and reaction with combustion products. The results showed that the amount of NOx could be substantially reduced up to 80% with the injection timing and the fraction of Urea in the solution optimized
Investigation of split injection in a single cylinder optical diesel engine
No full textSAE paper 2010-01-0605, Copyright © 2010 SAE International. This paper is posted on this site with permission from SAE International, and is for viewing only. Further use and distribution of this paper is not permitted without permission from SAE.Over the last decade, the diesel engine has made dramatic progress in its performance and market penetration. However, in order to meet future emissions legislations, Nitrogen Oxides (NOx) and particulate matters’ (PM) emissions will need to be reduced simultaneously. Nowadays researchers are focused on different combustion modes which can have a great potential for both low soot and low NOx. In order to achieve this, different injection strategies have been investigated.
This study investigates the effects of split injection strategies with high levels of Exhaust Gas Recirculation (EGR) on combustion performance and emissions in a single cylinder direct injection optical diesel engine. The investigation is focused on the effects of injection timing of split injection strategies.
A Ricardo Hydra single cylinder optical engine was used in which conventional experimental methods like cylinder pressure data, heat release analysis and exhaust emissions analysis were applied. Optical techniques like direct spray and combustion visualization were applied by means of a high speed imaging system with a copper vapor laser illumination system and a high-speed two-color system was applied to obtain in-cylinder diesel combustion temperature and soot measurements distributions
Investigation of split injection in a single cylinder optical diesel engine
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Over the last decade, the diesel engine has made dramatic progress in its performance and market penetration. However, in order to meet future emissions legislations, Nitrogen Oxide (NOx) and particulate matter (PM) emissions will need to be reduced simultaneously. Nowadays researchers are focused on different combustion modes like homogeneous charge compression ignition (HCCI) combustion and premixed charge compression ignition (PCCI) which have a great potential for both low soot and low NOx. In order to achieve these combustion modes, different injection strategies have been investigated.
This study investigates the effects of split injection strategies with high levels of Exhaust Gas Recirculation (EGR) on combustion performance and emissions in a high speed direct injection optical diesel engine. The investigation is focused on the effects of split injections at different injection pressures, injection timings and dwell angles using base diesel and biodiesel fuels.
The effect of fuel properties has been also investigated as an attempt to reduce regulated exhaust emissions in diesel engines. Performance, emissions and combustion characteristics have been examined for two different biodiesel fuels, namely BTL 50 and BTL 46.
A Ricardo Hydra single cylinder optical engine was used in which conventional experimental methods like cylinder pressure data, heat release analysis and exhaust emissions analysis were applied. Optical techniques like direct spray and combustion visualization were applied by means of a high speed imaging system with a copper vapour laser illumination system.
A high-speed two-colour system has been developed and implemented to obtain in-cylinder diesel combustion temperature and soot measurements to gain better understanding of the mixture formation and combustion processes.
This investigation concludes that the split injection strategies show potential to achieve low emissions combustion
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Experimental Study of the Combustion Process in a Heavy–Duty DI Diesel Engine for Different Injection Scenarios
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