Investigation of single and split injection strategies in an optical diesel engine

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University, 22/12/2010.This study investigates the effects of a split injection strategy on combustion performance and exhaust emissions in a high speed direct injection optical diesel engine. The investigation is focused on the effects of injection timing, quantity, and the dwell angle between the injections using commercially available diesel fuel. Three different split injection strategies including 50:50, 30:70, and 70:30 have been investigated. Additionally, the effect of total injected fuel quantity using total fuel quantities of 10 mm3 and 20 mm3 has been investigated. Moreover, the effect of variable and fixed dwell angle in split injections has been examined for five different values between 5o CA and 25o CA in the case of variable and 10o CA for the fixed dwell timing. The last parameter investigated was the injection timing, nine injection timings have been tested for each of the strategies. A Ricardo Hydra single cylinder optical engine running at 1500 rpm was used in this investigation. Conventional methods such as direct in-cylinder pressure measurements and heat release rate analysis have been employed. In addition, optical techniques such as high speed video imaging and two-colour have been applied, aimed at in depth analysis of the effects of the aforementioned parameters on engine performance and emissions. Furthermore, a significant amount of effort was devoted to the development and application of the Laser Induced Excipex Fluorescence (LIEF) technique so that simultaneous fuel liquid and fuel vapour distribution could be visualised. This investigation concludes that split injection strategies have the potential to reduce diesel exhaust emissions while maintaining a good level of fuel economy, provided that injection timings and the dwell angle between injections are appropriately selected. Further investigations are required in order to examine the effect of split injection under different engine operating conditions and speeds. In addition, the effect of alternative fuels must be considered. Moreover, the application of LIEF technique for quantitative fuel vapour concentration measurement should be considered through further optimisation of the LIEF system and careful calibration experiments.Financial support from Delphi Diesel Systems UK was used for this study

Investigation of single and split injection strategies in an optical diesel engine

This study investigates the effects of a split injection strategy on combustion performance and exhaust emissions in a high speed direct injection optical diesel engine. The investigation is focused on the effects of injection timing, quantity, and the dwell angle between the injections using commercially available diesel fuel. Three different split injection strategies including 50:50, 30:70, and 70:30 have been investigated. Additionally, the effect of total injected fuel quantity using total fuel quantities of 10 mm3 and 20 mm3 has been investigated. Moreover, the effect of variable and fixed dwell angle in split injections has been examined for five different values between 5o CA and 25o CA in the case of variable and 10o CA for the fixed dwell timing. The last parameter investigated was the injection timing, nine injection timings have been tested for each of the strategies. A Ricardo Hydra single cylinder optical engine running at 1500 rpm was used in this investigation. Conventional methods such as direct in-cylinder pressure measurements and heat release rate analysis have been employed. In addition, optical techniques such as high speed video imaging and two-colour have been applied, aimed at in depth analysis of the effects of the aforementioned parameters on engine performance and emissions. Furthermore, a significant amount of effort was devoted to the development and application of the Laser Induced Excipex Fluorescence (LIEF) technique so that simultaneous fuel liquid and fuel vapour distribution could be visualised. This investigation concludes that split injection strategies have the potential to reduce diesel exhaust emissions while maintaining a good level of fuel economy, provided that injection timings and the dwell angle between injections are appropriately selected. Further investigations are required in order to examine the effect of split injection under different engine operating conditions and speeds. In addition, the effect of alternative fuels must be considered. Moreover, the application of LIEF technique for quantitative fuel vapour concentration measurement should be considered through further optimisation of the LIEF system and careful calibration experiments.EThOS - Electronic Theses Online ServiceDelphi Diesel Systems UKGBUnited Kingdo

Simultaneous imaging of diesel spray atomisation and evaporation processes in a single-cylinder CR diesel engine

This document is the Accepted Manuscript version of the following article: Mohammad Reza Herfatmanesh, Mohammadreza Anbari Attar, and Hua Zhao, ‘Simultaneous imaging of diesel spray atomisation and evaporation processes in a single-cylinder CR diesel engine’, Experimental Thermal and Fluid Science, Vol. 50, pp. 10-20, October 2013. © 2013 Elsevier Inc. This manuscript version is made available under the terms of the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/. The Version of Record is available online at DOI: https://doi.org/10.1016/j.expthermflusci.2013.04.019 :In direct injection diesel engines, combustion and formation of pollutants are directly influenced by the spatial and temporal distributions of the injected fuel. In this study mixture formation during the pre-combustion phase of a diesel engine was investigated using the laser-induced exciplex fluorescence (LIEF) technique. The main purpose of this investigation was to develop an experimental setup capable of providing the full-field view of both liquid and vapour phases of evaporating diesel sprays during the fuel injection process inside the combustion chamber of a diesel engine with optical access. An expanded laser beam was employed for full combustion chamber visualisation. In this study two model fuels were tested; one consisted of 89% decane, 10% α-methyl-naphthalene and 1% TMPD and the other 88% decane, 10% α-methyl-naphthalene and 2% TMPD. The spray atomisation and evaporation processes during the pre-combustion phase of a diesel engine were measured at an injection pressure of 1200 bar and the engine speed of 1500 rpm. The results demonstrated the capability of the full-field LIEF technique in simultaneous imaging of liquid fraction and fuel vapour distribution during high pressure fuel injection process. It also highlighted the effect of dopant concentration on the fluorescence intensity of liquid and vapour signals. The exciplex system containing 1% TMPD produced better visualisation of the liquid phase, though the crosstalk in the vapour phase precluded accurate detection of the vapour phase signal. In contrast, the exciplex system containing 2% TMPD resulted in satisfactory visualisation of the vapour phase; however the intensity of the liquid phase was compromised as a result. This was presumed to be mainly due to the spectral shift of the exciplex species and/or TMPD decomposition at elevated temperatures and pressures.Peer reviewedFinal Accepted Versio

Turbulent flame boundary and structure detection in an optical DISI engine using tracer-based two-line PLIF technique

This is the Accepted Manuscript version of the following article: M. A. Attar, H. Zhao, M. R. Herfatmanesh, and A. Cairns, “Turbulent flame boundary and structure detection in an optical DISI engine using tracer-based two-line PLIF technique”, Experimental Thermal and Fluid Science, Vol. 68: 545-558, November 2015. The final published version is available at: https://doi.org/10.1016/j.expthermflusci.2015.06.015 © 2015 Elsevier Inc. All rights reserved.Design and development of new combustion system for Spark Ignition Direct Injection (DISI) engines requires thorough understanding of the flame as it develops from electric discharge and propagates across the combustion chamber. The main purpose of this work was to develop an experimental setup capable of investigating premixed and partially-premixed turbulent flame boundary and structure inside combustion chamber of a DISI engine. For this purpose the tracer-based two-line Planar Laser Induced Fluorescence (PLIF) technique was set up. In order to have a thermometry technique independent of photophysical models of dopant tracer, a specially designed Constant Volume Chamber (CVC) was utilized for quasi in situ calibration measurements. The thermometry technique was evaluated by measurements of average in-cylinder charge temperature during compression stroke for both motoring and firing cycles and comparing the results with temperature values calculated from in-cylinder pressure data. The developed technique was successfully employed to detect flame boundary and structure during combustion process in the optical engine. The present study demonstrated that as the two-line PLIF thermal images are independent of species concentration and flame luminosity they can be utilized as accurate means for flame segmentation. The proposed technique has the potential to be utilized for study of turbulent flames in non-homogeneously mixed systems.Peer reviewedFinal Accepted Versio

Proceedings of Abstracts Engineering and Computer Science Research Conference 2019

© 2019 The Author(s). This is an open-access work distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. For further details please see https://creativecommons.org/licenses/by/4.0/. Note: Keynote: Fluorescence visualisation to evaluate effectiveness of personal protective equipment for infection control is © 2019 Crown copyright and so is licensed under the Open Government Licence v3.0. Under this licence users are permitted to copy, publish, distribute and transmit the Information; adapt the Information; exploit the Information commercially and non-commercially for example, by combining it with other Information, or by including it in your own product or application. Where you do any of the above you must acknowledge the source of the Information in your product or application by including or linking to any attribution statement specified by the Information Provider(s) and, where possible, provide a link to this licence: http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/This book is the record of abstracts submitted and accepted for presentation at the Inaugural Engineering and Computer Science Research Conference held 17th April 2019 at the University of Hertfordshire, Hatfield, UK. This conference is a local event aiming at bringing together the research students, staff and eminent external guests to celebrate Engineering and Computer Science Research at the University of Hertfordshire. The ECS Research Conference aims to showcase the broad landscape of research taking place in the School of Engineering and Computer Science. The 2019 conference was articulated around three topical cross-disciplinary themes: Make and Preserve the Future; Connect the People and Cities; and Protect and Care

Proceedings of Abstracts, School of Physics, Engineering and Computer Science Research Conference 2022

© 2022 The Author(s). This is an open-access work distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. For further details please see https://creativecommons.org/licenses/by/4.0/. Plenary by Prof. Timothy Foat, ‘Indoor dispersion at Dstl and its recent application to COVID-19 transmission’ is © Crown copyright (2022), Dstl. This material is licensed under the terms of the Open Government Licence except where otherwise stated. To view this licence, visit http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: [email protected] present proceedings record the abstracts submitted and accepted for presentation at SPECS 2022, the second edition of the School of Physics, Engineering and Computer Science Research Conference that took place online, the 12th April 2022

Experimental investigation of hydraulic effects of two-stage fuel injection on fuel-injection systems and diesel combustion in a high-speed optical common-rail diesel engine

The final, definitive version of this paper has been published in International Journal of Engine Research, Vol 15 Issue 1, September 2012, ppublished by SAGE Publishing, All rights reserved.In order to meet the ever more stringent emission standards, significant efforts have been devoted to the research and development of internal combustion engines. The requirements for more efficient and responsive diesel engines have led to the introduction and implementation of multiple injection strategies. However, the effects of such injection modes on the hydraulic systems, such as the high-pressure pipes and fuel injectors, must be thoroughly examined and compensated for since the combustion and the formation of pollutants in direct-injection engines are directly influenced by the spatial and temporal distribution of the injected fuel within the combustion chamber. This study investigated the hydraulic effects of two-stage fuel injection on diesel combustion and emissions. The fuel-injection system was characterised for all the tested strategies through the measurement of the fuel-injection rate and quantity. In particular, the interaction between the two injection events was identified. The effects of two-stage injection, dwell angle and the interactions between two consecutive injection events on the combustion process and the emissions were investigated in a high-speed direct-injection single-cylinder optical diesel engine using heat-release analysis and high-speed fuel spray and combustion visualisation techniques. The results indicated that the two-stage injection strategy has the potential for simultaneous reduction of nitrogen oxide, soot and unburned hydrocarbon emissions. The results suggested that an optimum fuel quantity in the first injection exists, 0–30%, with which simultaneous reduction of nitrogen oxide, soot and unburned hydrocarbon emissions can be achieved with the added benefits of improved engine performance, fuel economy and combustion noise. However, higher soot emissions were produced, mainly due to the interaction between the two consecutive fuel-injection events whereby the fuel sprays during the second injection were injected into burning regions, as well as reduced soot oxidation due to the continuation of the combustion into the expansion stroke.Peer reviewedFinal Accepted Versio

Experimental investigation of effects of dwell angle on fuel injection and diesel combustion in a high-speed optical CR diesel engine

The final, definitive version of this paper has been published in Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, Vol 227 (2), August 2012, published by SAGE Publishing, All rights reserved.In order to meet the ever-more stringent emission standards, significant efforts have been devoted to the research and development of cleaner internal combustion engines. Diesel combustion and the formation of pollutants are directly influenced by the spatial and temporal distribution of the fuel injected. This study investigated the effects of dwell angle of split injection on diesel combustion and emissions in a high-speed common rail direct injection optical diesel engine. The fuel injection system was characterized through the measurement of the fuel injection rate and quantity for the tested strategies on a fuel injection test rig. In particular, the interaction between the two injection events was identified. Effects of the split injection dwell angle and the interactions of the two consecutive injection events on diesel combustion and exhaust emissions were then investigated in the single cylinder optical engine using heat release analysis and optical diagnostic techniques. The fuel injection process was illuminated by a high repetition copper vapour laser and recorded synchronously by a high speed video camera. The combustion temperature and soot distribution during the combustion process were measured by a recently developed high speed two-colour system. The results indicated that this injection mode has the potential to improve fuel economy and engine performance while substantially reducing the combustion noise, provided that the injection timings are appropriately selected.Peer reviewe

Analysis of Standby Power in an Enclosed High-Speed Flywheel Energy Storage System Using the CFD-ANOVA Approach

© 2023 SAE International. This is the accepted manuscript version of an article which has been published in final form at https://saemobilus-sae-org.ezproxy.herts.ac.uk/content/2023-32-0069/During urban driving, a significant amount of energy is lost due to continuous braking, which can be recovered and stored. The flywheel energy storage system (FESS) can efficiently recover and store the vehicle's kinetic energy during deceleration. However, standby losses in FESS, primarily due to aerodynamic drag, can affect its overall efficiency. To address this issue, the flywheel rotor is typically housed in a dedicated housing maintained at a low pressure using a vacuum pump. Standby power is known as the total power used by the auxiliary systems and the power needed to overcome drag and keep the flywheel rotor at a specific state of charge. The Analysis of Variance (ANOVA) technique was combined with the computational fluid dynamics (CFD) technique in this study to determine the optimal flywheel design parameters and investigate their impact on standby power. The study's results demonstrated the optimal combination of the airgap size and the rotor's pressure cavity to achieve the lowest standby power.Peer reviewe