Browse Topic: Sodium

Items (62)
Are Internal Diesel Injector Deposits (IDID) Mainly Linked to Biofuel Chemical Composition or/and Engine Operation Condition?2019-01-00611/15/2019
The increased use of alternative fuels has been linked to performance deterioration of injectors and engines as a result of internal diesel injector deposits (IDID). The present paper investigates fuel composition impact on injector tendency to blockage. Three main areas were investigated : (1) deposits linked to paraffins and aromatics content; (2) deposits linked to biodiesel composition using fatty acid methyl esters (FAME) and hydrotreated vegetal oil (HVO); and (3) deposits linked to the presence of additives (Dodecenylsuccinic anhydride DDSA, Dodecenyl Succinimid DDSI and Sodium Naphthenate). A deposit formation method was developed for the injection bench in order to discriminate the impact of fuels on system performance in terms of fuel volume injected, injection duration and stability. Three operation conditions were tested to represent low, intermediate and high load. In addition, the influence of soaking time and injector heating temperature was evaluated. The nature of the deposit was studied based on its morphology and chemical composition determined using Scanning Electron Microscopy coupled with Energy Dispersive X-ray (SEM/EDX) Spectroscopy. Deposits were observed for all fuels, even the highly paraffinic biofuel like HVO. Two main results are presented: Firstly, the main impact of fuel soaking period and high load operation on the occurrence of IDID, it was observed that deposit formation can be controlled by the time the fuel remains in contact with the hot metallic surface of the injector; Secondly, the complex correlation between deposit nature and characteristics and the injector’s tendency to blockage, for example, there is no straightforward link between deposit thickness and injector blockage, other parameters seem to be more appropriate to predict injector blockage. These are discussed in more detail in this study.
Alves Fortunato, MairaLenglet, FrancisBen Amara, ArijStarck, Laurie
Enhancement of Thermal Fatigue Strength by the Addition of Calcium to Hypoeutectic Aluminum-Silicon Alloys2018-32-002710/30/2018
Several elements affect the structure of eutectic silicon in hypoeutectic aluminum alloys [1, 2, 3, 4]. Among them, calcium has been investigated to a lesser extent compared to the typically used sodium and strontium. In order to enhance the thermal fatigue strength of a small engine, the morphology of eutectic silicon in hypoeutectic aluminum-silicon alloys is controlled by the addition of calcium. In addition, the castability and mechanical properties are investigated. Hence, samples containing different amounts of calcium are prepared at different cooling rates during solidification. The results revealed that, with the increase in the calcium amount and the cooling rate, eutectic silicon exhibits a fine morphology in cross-sectional images. Particularly, with the addition of at least 62 mass ppm of calcium in a specific range of cooling rates, refined eutectic silicon is obtained. In order to clarify additional effects of the added calcium, the amount of dissolved gas, fluidity, and porosity defects are evaluated. The amount of dissolved gas and the fluidity do not change in the range of the investigated calcium amounts. However, the sizes of each of the shrinkage porosities decrease and the region where porosities generated is spread, with spread-out regions. The sample strength with refined eutectic silicon is evaluated by tension and thermal fatigue tests. Refined samples exhibit greater elongation and thermal fatigue strength compared with those of eutectic silicon with a coarse morphology. The addition of calcium leads to the effective enhancement of the mechanical properties of hypoeutectic aluminum-silicon alloys.
Watanabe, KentaroMotoyama, KojiroWatanabe, TomokazuIshihara, KazuhiroMaeda, Fujio
Sodium Cooling Efficiency in Hollow Valves for Heavy Duty Engines2018-01-03684/3/2018
As a consequence of the ongoing evolution of engines, where performance is continuously improving and the use of alternative fuels is being adopted by many engine manufacturers, thermal working conditions of the exhaust valves are increasingly critical. In order to better resist the higher temperature levels of the exhaust gases, current development ranges from improvement of the cooling concept for the overall system, new materials for valve set components up to the upgrade of the exhaust manifold material. Change in the design of several valvetrain components due to the increased thermal loads is a logical consequence of this technical evolution process. Hollow exhaust valves filled with Sodium (Na) are a known technology that is widely used in passenger car engines to improve thermal behavior and to avoid the need to change to expensive materials (Ni-base alloys). Nevertheless, shaker-cooling effect of Na for engine speeds below 3.000 [rpm] has been questioned in the past and this technology has not been fully explored in heavy duty (HD) applications [1]. In order to investigate the thermal efficiency or effectiveness and to confirm Na-filled valves as a potential technical solution for thermal issues in HD engines, back-to-back analyses (FEA) and tests (temperature measurements and endurance) were performed, mainly focused on heavy duty spark ignition (SI) engines (gas fueled) and on severe applications of diesel engines.
Zenklusen, FernandoCoenca, MarcioPuck, Alexander
The Effect of Near-Zero Aromatic Fuels on Internal Diesel Injector Deposit Test Methods2017-01-08073/28/2017
Internal diesel injector deposits (IDID) are now a well understood phenomenon and a standard test procedure has been developed and partially approved by the Coordinating European Council (CEC). The engine test procedure has been approved for simulation of sodium soap deposits by dosing the test fuel with a sodium salt and dodecenyl succinic acid (DDSA), whilst amide lacquer deposits simulation by dosing the test fuel with a low molecular weight (MWt) polyisobutylene succinimide (PIBSI) is still under development. The solubility of these contaminants in the base fuel should be reasonably constant to achieve consistent results. With the introduction of diesel from varying sources, this study focused on the effect of near-zero aromatics EN 15940 compliant gas-to-liquids GTL diesel, very similar to hydrotreated vegetable oil (HVO), on IDID severity across two different engine platforms, and the response of a modern deposit control additive. The test results showed that, with the same level of contaminants, IDID severity did differ significantly when comparing GTL diesel to a petroleum diesel reference fuel. The IDID effects also differed across engine platforms. In a previous study, it was found that the effect of zinc solvency in the base fuel had a dramatic effect on the CEC F-98-08 DW10 injector nozzle fouling test results. For the IDID test procedure used in this study, the effect of base fuel solvency was less pronounced on IDID formation. It was also found that some degree of nozzle fouling does take place with typical IDID contaminants. The deposit control additive tested proved to be effective in preventing both IDID formation and nozzle fouling for GTL diesel and petroleum diesel. In conclusion, it was highlighted again that base fuel solvency can influence the results of a test procedure where contaminants are dosed into the fuel, and these effects need to be considered where such fuels are tested.
de Goede, StefanBarbour, RobertVelaers, AdrianSword, BrianBurton, DanielMokheseng, Konrad
Chemical Composition of Ashless Polymeric Internal Diesel Injector Deposits2014-01-272810/13/2014
Internal Diesel Injector Deposits (IDIDs) have been known for some time. With the latest powertrains becoming ever more sophisticated and reliant on efficient fuel delivery, the necessity for a continued focus on limiting their formation remains. Initial studies probed both carbonaceous based/ashless polymeric and sodium salt based IDIDs. The reported occurrence of the latter variety of IDID has declined in recent years as a result of the removal of certain additives from the diesel distribution system. Conversely, ashless polymeric based deposits remain problematic and a regular occurrence in the field. The body of work presented in this contribution is an extension to that reported in SAE paper 2014-01-1401 which showed how a particular Fuel Borne Catalyst (FBC) additive has the ability to significantly reduce the formation of ashless polymeric deposits formed from the reaction of Poly-isobutylene Succinic Imides (PIBSI) with fatty acid and the ability for the same additive to also be neutral towards the formation of sodium salt based deposits. There has been significant debate regarding the composition of such deposits, particularly for the ashless polymeric type. For this reason, here detailed is a full chemical analysis of the deposit formed in the ashless polymeric deposit programme conducted. The protocol developed can be easily run and provides a clear view of the composition of this type of deposit. The techniques used - Scanning Electron Microscopy with Energy Dispersive X-Ray Analysis (SEM/ EDX), X-ray Photoelectron Spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (ToFSIMS) amongst others - permitted the identification of the deposit chemistry present on the injector surface. The results were further confirmed comparing injectors which were shown to seize with contaminated diesel and others that remained free as a result of using the FBC additive.
Dallanegra, RomaeoCaprotti, Rinaldo
Engine Testing of Dissolved Sodium Borohydride for Diesel Combustion CO 2 Scrubbing2014-01-272910/13/2014
Improvements in the efficiency of internal combustion engines and the development of renewable liquid fuels have both been deployed to reduce exhaust emissions of CO2. An additional approach is to scrub CO2 from the combustion gases, and one potential means by which this might be achieved is the reaction of combustions gases with sodium borohydride to form sodium carbonate. This paper presents experimental studies carried out on a modern direct injection diesel engine supplied with a solution of dissolved sodium borohydride so as to investigate the effects of sodium borohydride on combustion and emissions. Sodium borohydride was dissolved in the ether diglyme at concentrations of 0.1 and 2 % (wt/wt), and tested alongside pure diglyme and a reference fossil diesel. The sodium borohydride solutions and pure diglyme were supplied to the fuel injector under an inert atmosphere and tested at a constant injection timing and constant engine indicated mean effective pressure (IMEP). The 0.1 % sodium borohydride diglyme solution and pure diglyme exhibited durations of ignition delay shorter than that of the reference fossil diesel, while testing of the 2 % sodium borohydride solution resulted in failure of the fuel injector. Addition of the dissolved sodium borohydride was found to increase the duration of fuel injection required to maintain a constant engine IMEP by as much as 50 %, with a concurrent increase in the duration of combustion also observed. Levels of exhaust unburnt hydrocarbons did not increase with the addition of sodium borohydride suggesting a detrimental effect of the sodium borohydride on the injector efficiency. Measurement of exhaust emissions of particulate mass and scanning electron microscopy (SEM) of exhaust soot samples both indicated greatly increased soot emissions with the addition of sodium borohydride. Chemical analysis of the exhaust soot samples found no evidence of sodium carbonate or bicarbonate compounds, possibly suggesting deposition of sodium compounds inside the engine combustion chamber.
Hellier, PaulLadommatos, NicosHeaden, TomBennington, Stephen
Validation of Fuel Borne Catalyst Technology in Advanced Diesel Applications2014-01-14014/1/2014
The use of Diesel Particulate Filters (DPFs) as a means to meet ever more stringent worldwide Particulate Matter/ Particle Number (PM/ PN) emissions regulations is increasing. Fuel Borne Catalyst (FBC) technology has now been successfully used as an effective system for DPF regeneration in factory and service fill as well as retrofit applications for several years. The use of such a technology dictates that it be stable in long term service and that it remains compatible with new and emerging diesel fuel grades. In order to ensure this, neat additive stability data have been generated in a very severe and highly transient temperature cycle and a large selection of current (Winter 2012) market fuels have been evaluated for stability with this FBC technology. Results indicate that FBC technology remains suitable. The incidence of Internal Diesel Injector Deposits (IDIDs) is increasing, particularly for advanced FIE systems. These deposits generate a variety of field issues that can, in extreme cases, require the fitting of a new set of injectors. IDIDs have been studied using a representative bench engine test (sodium based deposits) and injector rig (ashless polymeric based deposits), whereby baseline deposit formation seen in the field has been shown to be reproducible. The results indicate that the effect of the FBC technology tested is neutral for sodium salt based IDIDs whilst benefits are observed for ashless polymeric IDIDs. The rigorous FBC testing data reported confirm that appropriate FBC technology can continue to be reliably deployed in the field and, in the tests carried out, can also help prevent issues associated with ashless polymeric IDIDs.
Dallanegra, RomaeoCaprotti, Rinaldo
Internal Injector Deposits From Sodium Sources2014-01-13884/1/2014
There have been reports of internal injector deposits causing problems in diesel engines in the field from 2008. Such problems manifest themselves as rough idling, power loss, high emissions, high-pressure fuel pump wear, injector sticking, internal component corrosion and engine failure. These reports coincided with the use of common rail diesel injection systems and of ultra-low sulphur fuels introduced because of emission regulation demands. The injection systems have design features that are more conducive or susceptible to deposit formation such as severe high temperature and pressure operating conditions, the tolerances of critical parts, and lower force internal component actuation. The changes to fuels have also affected the fuels ability to solubilise these deposits. The deposits formed manifest themselves in complex form in the field, often being mixtures of inorganic and organic compounds. One sub-group of this complex picture that is of current major interest is “sodium soaps”, also known as sodium carboxylates. Various sources of sodium have been used to research IDID with varying results. Work with the different sodium precursors, sodium hydroxide and sodium 2-ethylhexanote (a fuel soluble sodium salt) showed that interaction with monoacid lubricity additives produced filter blocking in one case and injector sticking in the other. With the possible development of a standard engine test it is important to understand the effects of a variety of sodium sources to ensure any future test reflects field problems. Investigation of a number of sodium salts and their interactions with different acid species in fuels are described in this paper. The effect of water and other factors are also presented. Finally, a commercial deposit control additive that is effective in controlling this type of IDID is provided.
Reid, JacquelineCook, StephenBarker, Jim
Sodium Contamination of Diesel Fuel, its Interaction with Fuel Additives and the Resultant Effects on Filter Plugging and Injector Fouling2013-01-268710/14/2013
Diesel fuel distilled from crude oil should contain no greater than trace amounts of sodium. However, fuel specifications do not include sodium; there is a limit of five parts per million for the amount of sodium plus potassium in fatty acid methyl esters (FAME) used as biodiesel. Sodium compounds are often used as the catalyst for the esterification process for producing FAME and sodium hydroxide is now commonly used in the refining process to produce ultra-low sulphur diesel (ULSD) fuel from crude oil. Good housekeeping should ensure that sodium is not present in the finished fuel. A finished fuel should not only be free of sodium but should also contain a diesel fuel additive package to ensures the fuel meets the quality standards introduced to provide reliable operation, along with the longevity of the fuel supply infrastructure and the diesel engines that ultimately burn this fuel. There has recently been an upsurge in reported field problems due to fouling of the fuel injection system in modern diesel engines. This can take the form of deposits in the fuel filters or within the fuel injectors themselves. Recent work proposed a mechanism whereby sodium contaminated fuel can undergo adverse reactions between the sodium compounds and fuel additives leading to the formation of material that can impede the operation of diesel fuel injectors. This paper presents new work carried out to enhance the understanding of this mechanism and demonstrates that the fate of any sodium contaminant is highly dependent on (i) the fuel additives present in the fuel (ii) the amount of water in the system, (iii) potentially the intensity of fuel/water mixing and (iv) the identity of the sodium salt involved in the reaction. This can lead to sodium accumulating in the water bottoms, forming sodium compounds that go on to plug fuel filters or which may cause injector fouling. The data found may explain the variation in engine test data regarding sodium induced fouling reported in the recent literature.
Barker, JimCook, StephenRichards, Paul
De-Icer Quantification and Phase Transition Detection by Raman Spectroscopy2013-01-21019/17/2013
Winter maintenance is based on the intervention of operating services, as well as the use of deicers. Each year, in France, thousands of tons of deicers are spread through runways and taxiways. On the airport sector, the main deicers are sodium or potassium acetates and formates. All these deicers aim to prevent ice formation (preventive strategy) and/or improve the ice melting of snow residual film (curative strategy) at temperatures below 0°C. The operating principle of these compounds is based on the lowering of the solution's freezing point once dissolved in water. The phase diagram's knowledge is predominant to determine the deicer's amount to be applied on the surface. It provides a way to optimize their amounts applied with respect to weather conditions, present or forecasted. The Center for Technical Studies of Equipment in East of France (CETE de l'Est) developed and implemented a method based on Raman spectroscopy to characterize aqueous solutions of airport de-icers. This application determines the phase transition temperatures of these solutions, according to their concentration. The spectroscopic tool being portable, its use could be easily conducted on the field, avoiding any sample collections. Furthermore, this spectroscopic tool enables the determination of the amount of de-icers used to generate the solution. This study also highlighted some differences between the freezing curves of different deicers, as well as the possible presence of phases with unknown chemical and mechanical properties, such as the metastable phase potassium formate. Additional lessons related to winter maintenance could be taken, on the shelf-life of these products as an example.
Durickovic, IvanaMarchetti, MarioPoissonnier, StephanieCasteran, GuillaumeMansour, RachelSchweigert, NathalieMars, Benoit
Possible Mechanism for Poor Diesel Fuel Lubricity in the Field2012-01-08674/16/2012
Traditionally, diesel fuel injection equipment (FIE) has frequently relied on the diesel fuel to lubricate the moving parts. When ultra low sulphur diesel fuel was first introduced into some European markets in the early 1980's it rapidly became apparent that the process of removing the sulphur also removed other components that had bestowed the lubricating properties of the diesel fuel. Diesel fuel pump failures became prevalent. The fuel additive industry responded quickly and diesel fuel lubricity additives were introduced to the market. The fuel, additive and FIE industries expended much time and effort to develop test methods and standards to try and ensure this problem was not repeated. Despite this, there have recently been reports of fuel reaching the end user with lubricating performance below the accepted standards. Recent publications have also suggested that it is not uncommon for sodium hydroxide used in the fuel refining industry to be present in fuel entering the supply chain downstream of the refinery. Due to the chemical nature of some lubricity additives there is clearly the possibility of interaction. This paper briefly reviews the need for diesel fuel lubricity improver additives, previous work on such additives and possible interactions. It then goes on to present new work performed to investigate how the presence of sodium compounds in the fuel may affect the performance of a range of lubricity additives of different chemistries. It shows that the presence of the sodium hydroxide can lead to reactions with and hence the depletion of certain types of lubricity additive. This could inevitably lead to reduced lubricity performance and fuels reaching the customer that do not meet specification.
Cook, StephenBarker, JimReid, JacquelineRichards, Paul
Colorimetric-Solid Phase Extraction (C-SPE): In-Flight Methodologies for the Facile Determination of Trace Level Indicators of Water Quality2008-01-22016/29/2008
At present, spacecraft water quality is assessed when samples collected on the International Space Station (ISS) are returned to Earth. Several months, however, may pass between sample collection and analysis, potentially compromising sample integrity by risking degradation. For example, iodine and silver, which are the respective biocides used in the U.S. and Russian spacecraft potable water systems, must be held at levels that prevent bacterial growth, while avoiding adverse effects on crew health. A comparable need exists for the detection of many heavy metals, toxic organic compounds, and microorganisms. Lead, cadmium, and nickel have been found, for instance, in the ISS potable water system at amounts that surpass existent requirements. There have been similar occurrences with hazardous organic compounds like formaldehyde and ethylene glycol. Microorganism counts above acceptable limits have also been reported in a few instances. The delays in analyzing potable water suspend implementation of any real-time correction scenarios to an on-board contaminant event. It is, therefore, critical that rapid, on-board methods be developed to monitor trace quantities of several indicators of quality in spacecraft drinking water supplies. To meet some of these needs, our laboratory has developed colorimetric-solid phase extraction (C-SPE). C-SPE is a sorption-spectrophotometric platform that entails the selective extraction and concentration of analytes by a membrane impregnated with a colorimetric reagent, followed by quantification on the membrane surface using a diffuse reflectance spectrophotometer. As such, we have designed and tested C-SPE methods for monitoring iodine, silver, nickel and lead. We have also devised methods to extend C-SPE to determinations of formaldehyde, pH, cadmium, and arsenic. This presentation provides a status report on the development of C-SPE to meet these needs, including results from tests in microgravity simulations via KC-135 and C-9 fights.
Porter, Marc D.Siperko, Lorraine M.Nordling, JohnHazen-Bosveld, April A.Shih, Chien-JuLipert, Robert J.Fritz, James S.
Potassium AMTEC Cell Performance1999-01-27028/2/1999
AMTEC systems have historically been operated with sodium as the working fluid, in large part because fabrication of beta”-alumina solid electrolyte (BASE) membranes has been substantially easier with sodium than with potassium or other alkali metals1. It has been anticipated that because potassium has a substantially higher vapor pressure for a given temperature, and because the best K-BASE conductivity falls only marginally below that for Na-BASE, potassium AMTEC cells could produce higher power at a given temperature or comparable power at a lower temperature than similar sodium cells. Operation at lower temperatures can reduce materials lifetime or compatibility problems, and for severely heat input constrained systems it could enhance efficiency by reducing parasitic thermal conduction losses. Recently K-BASE tubes have become available as a commercial product2 and conventional experiments to evaluate the performance of complete KAMTEC cells have become much more feasible. Previous experiments on K-BASE have focused primarily on measurements in non-power producing cell environments. One AMTEC cell experiment was carried out at low temperature.3 We report here initial experiments on the power output performance of KBASE with a conventional TiN cathode in a standardized single-pass AMTEC test cell. The performance data are compared to tests of Na-BASE cells under similar conditions and with similar electrodes. Peak power for a 6 cm2 TiN electrode on a K-BASE cell was substantially higher than has been observed for the best, comparable Na-BASE cells. The power improvement corresponded to that for a temperature increase of ~ 60 K for the Na- BASE cell.
Barkan, A.Hunt, T. K.Thomas, B.
Efficiency of an AMTEC Recirculating Test Cell, Experiments and Projections9291428/3/1992
The alkali metal thermal to electric converter (AMTEC) is an electrochemical device for the direct conversion of heat to electrical energy with efficiencies potentially near Carnot. The future usefulness of AMTEC for space power conversion depends on the efficiency of the devices. Systems studies have projected from 15% to 35% thermal to electric conversion efficiencies, and one experiment has demonstrated 19% efficiency for a short period of time. Recent experiments in a recirculating test cell (RTC) have demonstrated sustained conversion efficiencies as high as 10.2% early in cell life and 9.7% after maturity. Extensive thermal and electrochemical analysis of the cell during several experiments demonstrated that the efficiency could be improved in two ways. First, the electrode performance could be improved. The electrode for these tests operated at about one third the power density of state of the art electrodes. The low power density was caused by a combination of high series resistance and high mass flow resistance. Reducing these resistances could improve the efficiency to greater than 10%. Second, the cell thermal performance could be improved. Efficiencies greater than 14% could be realized through reducing the radiative thermal loss. Further improvements to the efficiency range predicted by systems studies can be accomplished through the development and use of an advanced condenser with improved reflectivity, close to that of a smooth sodium film, and the series connecting of individual cells to further reduce thermal losses.
Underwood, M. L.O'Connor, D.Williams, R. M.Jeffries-Nakamura, B.Ryan, M. A.
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