| 1. |
- Johansson, Monica, 1979, et al.
(författare)
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NOx and soot emissions trends for RME, SME and PME fuels using engine and spray experiments in combination with simulations
- 2013
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361. ; 106, s. 293-302
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Tidskriftsartikel (refereegranskat)abstract
- This study includes engine tests with neat FAME fuels and blends of 7% and 30% of RME in European Diesel, EN590 (non FAME added). The study was also completed with spray studies and numerical simulations for a deeper understanding of the engine results.The engine was operated at four operational points (A25, B50, B75 and C100) taken from the European Stationary Cycle, ESC cycle. The A25 case was also extended to achieve information how the soot emissions varies with the operational parameters; start of injection (SOI), NOx level (regulated by EGR) and needle opening pressure (NOP). The spray studies were performed in a high temperature/high pressure spray chamber at relevant conditions. For the numerical simulations the KIVA 3-V code was used with detailed chemical kinetics.The results shows that the neat FAME fuels lower the soot emissions by up to 90% compared with Diesel fuel. Moreover, even low blend ratios lowers the soot emissions significantly. Among the FAME fuels, combustion with PME had the lowest amount of soot emissions due to its lowest amount of di-and tri-unsaturated fatty acids (i.e. less double bonds) in comparison with SME and RME.The NOx emissions were increased for the neat FAME fuels in relation the Diesel fuel. The increase in NOx emissions for the neat FAME fuels is due to the higher flame temperature for the FAME fuels which could be a result of the oxygen content which causes a lower equivalence ratio (phi), i.e. leaner local reacting mixture.The A25 operational case showed that the most important factor to decrease soot emissions for Diesel fuel was NOP, while for the FAME fuels SOI had the greatest impact. Further, at constant level of NOx emissions for the included fuels it was observed that the FAME fuels still reduced the soot emissions significantly.The study shows that FAME fuels and Diesel blends with FAME fuels, can be a tool to meet future emission legislation, since low soot emissions levels can be reached for low NOx emissions and the fact that FAME fuels are renewable, the global warming impact is lower than for Diesel.
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| 2. |
- Yang, Junfeng, 1979, et al.
(författare)
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3D CFD modeling of a biodiesel-fueled diesel engine based on a detailed chemical mechanism
- 2012
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627.
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Tidskriftsartikel (refereegranskat)abstract
- A detailed reaction mechanism for the combustion of biodiesel fuels has recently been developed by Westbrook and co-workers [1]. This detailed mechanism involves 5037 species and 19990 reactions, which prohibits its direct use in computational fluid dynamic (CFD) applications. In the present work, various mechanism reduction methods included in the Reaction Workbench software [2] were used to derive a semi-detailed biodiesel combustion mechanism, while maintaining the accuracy of the master mechanism for a desired set of engine conditions. The reduced combustion mechanism for a five-component biodiesel fuel was employed in the FORTÉ CFD simulation package [3] to take advantage of advanced chemistry solver methodologies and advanced spray models. Simulations were performed for a Volvo D12C heavy diesel engine fueled by RME fuel using a 72° sector mesh. Predictions were validated against measured in-cylinder parameters and exhaust emission concentrations. The semi-detailed mechanism was shown to be an efficient and accurate representation of actual biodiesel combustion and emissions formation.
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| 3. |
- Yang, Junfeng, 1979, et al.
(författare)
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Engine performance and emissions formation for RME and conventional diesel oil: a comparative study
- 2009
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Ingår i: 2009 ASME Internal Combustion Engine Division Spring Technical Conference; Milwaukee, WI; United States; 3 May 2009 through 6 May 2009. - 1529-6598. - 9780791843406 ; , s. 125-134
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Konferensbidrag (refereegranskat)abstract
- A comparative study on engine performance andemissions (NOx, soot) formation has been carried out for theVolvo D12C diesel engine fueled by Rapeseed Methyl Ester,RME and conventional diesel oil. The combustion models,used in this paper, are the modifications of those described in[1-2]. After the compilation of liquid properties of RMEspecified as methyl oleate, C19H36O2, making up 60% of RME.The oxidation mechanism has been compiled based on methylbutanoate ester, mb, C5H10O2 oxidation model [3]supplemented by the sub-mechanisms for two proposed fuelconstituent components, methyl decanoate, md, C11H22O2, nheptane,C7H16, and soot and NOx formations reduced and“tuned” by using the sensitivity analysis. A special globalreaction was introduced to “crack” the main fuel intoconstituent components, md, mb and propyne, C3H4, toreproduce accurately the proposed RME chemical formula.The sub-mechanisms were collected in the general oneconsisting of 99 species participating in 411 reactions. Thecombustion mechanism was validated using shock-tubeignition-delay data at diesel engine conditions and flamepropagation speeds at atmospheric conditions.The engine simulations were carried out for Volvo D12Cengine fueled both RME and conventional diesel oil. Thenumerical results illustrate that in the case of RME, nearly100% combustion efficiency was predicted when thecumulative heat release, was compared with the RME LHV,37.2 kJ/g.. To minimize NOx emissions, the effects of 20-30%EGR levels depending on the engine loads and differentinjection strategies were analyses. To confirm the optimalengine operation conditions, a special technique based on the time-transient parametric j-T maps[4] has been used.
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| 4. |
- Yang, Junfeng, 1979, et al.
(författare)
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Numerical Analysis of NOx Formation Trends in Biodiesel Combustion using Dynamic ϕ-T Parametric Maps
- 2011
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Ingår i: 2011 JSAE/SAE International Powertrains, Fuels & Lubricants Meeting, Kyoto (Japan), Aug 29-Sep 2. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. ; , s. 16-
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Konferensbidrag (refereegranskat)abstract
- The use of biodiesel in conventional diesel engines results in increased NOx emissions; this presents a barrier to the widespread use of biodiesel. The origins of this phenomenon were investigated using the CFD KIVA3V code, which was modified to account for the physical properties of biodiesel and to incorporate semi-detailed mechanisms for its combustion and the formation of emissions. Parametric ϕ-T maps and 3D engine simulations were used to assess the impact of using oxygen-containing fuels on the rate of NO formation. It was found that using oxygen-containing fuels allows more O2 molecules to present in the engine cylinder during the combustion of biodiesel, and this may be the cause of the observed increase in NO emissions.
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| 5. |
- Golovitchev, Valeri, 1945, et al.
(författare)
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Construction of combusiton models for rapeseed methyl ester bio-diesel fuel for internal combusiton engine aplications
- 2009
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Ingår i: Biotechnology Advances. - : Elsevier BV. - 0734-9750. ; 27:5, s. 641-655
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Tidskriftsartikel (refereegranskat)abstract
- Bio-diesel fuels refer to non-petroleum based diesel fuels consisting of long chain alkyl esters produced by transesterifcation of vegetable oils, and proposed to be used (as neat or blended with conventional fuels) in unmodified diesel engines. Currently, there are few papers (see e.g. [1,2]) in which theoretical models for bio-diesel (e.g. RME) combustion simulations were reported. The models, developed in this paper, are modifications of those described in [1]. After the compilation of liquid fuel properties, the existing detailed mechanism of methyl butanoate ester, C5H10O2 [2, 3] oxidation was supplemented by sub-mechanisms for two proposed fuel constituent components, C7H16 and C7H8O (and, then, by mp2d and propyne, C3H4) to represent the combustion model of RME described by the chemical formula, C19H34O2 (or C19H36O2). The main fuel vapor thermal properties were taken as those of methyl palmitate C19H36O2 in the NASA polynomial form of the Burcat [4] database. The special global reaction was introduced to “crack” the main fuel into constituent components, which sub-mechanisms were collected in the general (309 species, 1472 reactions) including also soot and NOx formation processes. The detailed combustion mechanism was validated using shock-tube ignition-delay data at diesel engine conditions. For constant volume and diesel engine (Volvo D12C) combustion modeling, this mechanism was reduced to 88 species participating in 363 reactions.
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| 6. |
- Golovitchev, Valeri, 1945, et al.
(författare)
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Modeling of Combustion and Emissions Formation in Heavy Duty Diesel Engine Fueled by RME and Diesel Oil
- 2009
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Ingår i: SAE Technical Papers. - 0148-7191 .- 2688-3627. ; , s. 1-13
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Konferensbidrag (refereegranskat)abstract
- A comparative study on engine performance and emissions (NOx, soot) formation has been carried out for the Volvo D12C diesel engine fueled by Rapeseed Methyl Ester, RME and conventional diesel oil. The fuel and combustion models used in this paper are the modifications of those described in [1-3]. The numerical results for different load cases illustrate that for both fuels nearly 100% combustion efficiency was predicted; in the case of RME, the cumulative heat release was compared with the RME LHV, 37.2 kJ/g. To minimize soot and NOx emissions, 25-30% EGR levels depending on the engine loads and different injection timings were analyses. To illustrate the optimal engine performance conditions, a special technique based on the time-transient parametric -T maps [4] has been used.
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| 7. |
- Golovitchev, Valeri, 1945, et al.
(författare)
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Modeling of combustion and emissions formation in heavy duty diesel engine fueled by RME and diesel oil
- 2010
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Ingår i: SAE International Journal of Engines. - : SAE International. - 1946-3944 .- 1946-3936. ; 2:2, s. 355-367
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Tidskriftsartikel (refereegranskat)abstract
- A comparative study on engine performance and emissions (NOx, soot) formation has been carried out for the Volvo D12C diesel engine fueled by Rapeseed Methyl Ester, RME and conventional diesel oil. The fuel and combustion models used in this paper are the modifications of those described in [1-3]. The numerical results for different load cases illustrate that for both fuels nearly 100% combustion efficiency was predicted; in the case of RME, the cumulative heat release was compared with the RME LHV, 37.2 kJ/g. To minimize soot and NOx emissions, 25-30% EGR levels depending on the engine loads and different injection timings were analyses. To illustrate the optimal engine performance conditions, a special technique based on the time-transient parametric φ-T maps [4] has been used
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| 8. |
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| 9. |
- Han, Y., et al.
(författare)
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A study on the dynamic responses and injury mechanism of human chest in vehicle-pedestrian collisions
- 2015
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Ingår i: Qiche Gongcheng/Automotive Engineering. - 1000-680X. ; 25:5, s. 516-519, 537
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Tidskriftsartikel (refereegranskat)abstract
- With THUMS pedestrian FE model, simulations on vehicle-pedestrian crash are conducted for four types of vehicles (medium sedan, minicar, van and SUVs) with different front-end structures at a impact speed of 20, 30, 40 and 50km/h to analyze pedestrian chest dynamic response and chest impact conditions as well as the chest deformation modes and injuries of pedestrian including rib deflections. The results demonstrate that the front-end structure of vehicle has significant effects on the dynamic response and chest impact speed of pedestrian and the stiffness distribution of vehicle front-end structure is a major factor affecting the rib deflections and chest deformation mode of pedestrian.
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| 10. |
- Svensson, Mats, 1960, et al.
(författare)
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CFD MODELING OF PRESSURE TRANSIENTS IN THE SPINAL CANAL DURING WHIPLASH MOTION – A PILOT STUDY
- 2009
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Ingår i: IRCOBI Conference. - 9783033020504 ; , s. 415-418
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Konferensbidrag (refereegranskat)abstract
- The objective of this study was to make use of recent developments in Computational FluidDynamics (CFD) modeling to investigate the pressure phenomena and the hypothesized concomitant veinblood flow that take place in the spinal canal during extension and flexion motion of the cervical spine.
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