| 1. |
- Bernemyr, Hanna, et al.
(author)
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Study of Nozzle Fouling : Deposit Build-Up and Removal
- 2019
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In: SAE technical paper series. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191. ; :December
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Journal article (peer-reviewed)abstract
- The global demand for decreased emission from engines and increased efficiency drives manufactures to develop more advanced fuel injection systems. Today's compression-ignited engines use common rail systems with high injection pressures and fuel injector nozzles with small orifice diameters. These systems are highly sensitive to small changes in orifice diameters since these could lead to deteriorations in spray characteristics, thus reducing engine performance and increasing emissions. Phenomena that could create problems include nozzle fouling caused by metal carboxylates or biofuels. The problems increase with extended use of biofuels. This paper reports on an experimental study of nozzle hole fouling performed on a single-cylinder engine. The aim was to identify if the solubility of the fuel has an effect on deposit build-up and, thus, the reduction in fuelling with associated torque loss, and if there is a probability of regenerating the contaminated injectors. Additionally, the influence of the nozzle geometry was tested by using injectors of various designs. In the experiments, high-load engine operation was used to create the effect of fouling in the presence of zinc-neodecanoate. Solubility properties of the fuel were tested by using high- A nd low-aromatic-content diesel fuels. To gain insight into the morphology and chemical characteristics of the deposits, the nozzles were opened and examined with scanning electron microscopy/energy dispersive X-ray (SEM/EDX). The results showed higher power loss in low-aromatic-content fuels. The experiments also showed regained engine power within an hour using uncontaminated fuel in a fouled nozzle. A three steps process is proposed as the mechanism for deposit build-up and removal in injector nozzles. It is suggested that fouling of the injector is equilibrium between the different steps of the mechanisms.
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| 2. |
- Csontos, Botond, et al.
(author)
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Characterization of Deposits Collected from Plugged Fuel Filters
- 2019
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In: SAE technical paper series. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191. ; 2019:September
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Journal article (peer-reviewed)abstract
- Fuel filters serve as a safety belt for modern compression ignition engines. To meet the requirements from environmental regulations these engines use the common rail injection system, which is highly susceptible to contamination from the fuel. Furthermore, the public awareness towards global warming is raising the need for renewable fuels such as biodiesel. An increased fuel variety brings a higher requirement for fuel filters as well. To better understand the process of filtration, awareness of the different possible contaminants from the field is needed. This study used several chemical characterization techniques to examine the deposits from plugged fuel filters collected from the field. The vehicle was run with a biodiesel blend available on the market. The characterization techniques included X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR) joined with attenuated total reflectance (ATR) sampling, gas chromatography-mass spectrometry (GC-MS), and lastly thermal gravimetric analyzer combined with FTIR and a GC-MS (TGA/FTIR/GC-MS). In addition the remaining ash from TGA was measured in energy-dispersive X-ray spectroscopy (EDX). Deposits were scraped from the used filter, and prepared for the different analytic methods. After cleaning the deposits with different solvents, GC-MS identified the traces of glycerol and sterols in the filter. After a transesterification reaction GC-MS could identify carboxylates corresponding to degraded biodiesel. The TGA/FTIR/GC-MS revealed the presence of polymeric compounds in the deposit. XRF did not require any previous cleaning, and was used to identify different metals present in the deposits. The mentioned deposits are characterized as soft particles, and could originate from the impurities of biodiesel, presence of engine oils, or degradation of the fuel. The presented results help to better understand the current concerns with the on-board filtration of fuels, and can help to create more robust fuel systems in the future.
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| 3. |
- Csontos, Botond, et al.
(author)
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Development of a Method to Measure Soft Particles from Diesel Type Fuels
- 2020
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In: SAE technical paper series. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191. ; :April
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Journal article (peer-reviewed)abstract
- Renewable fuels have an important role to create sustainable energy systems. In this paper the focus is on biodiesel, which is produced from vegetable oils or animal fats. Today biodiesel is mostly used as a drop-in fuel, mixed into conventional diesel fuels to reduce their environmental impact. Low quality drop-in fuel can lead to deposits throughout the fuel systems of heavy duty vehicles. In a previous study fuel filters from the field were collected and analyzed with the objective to determine the main components responsible for fuel filter plugging. The identified compounds were constituents of soft particles. In the current study, the focus was on metal carboxylates since these have been found to be one of the components of the soft particles and associated with other engine malfunctions as well. Hence the measurement of metal carboxylates in the fuel is important for future studies regarding the fuel's effect on engines. The first aim of this study was to create synthetic soft particles from biodiesel. Accelerated aging of fuels with different contaminations such as engine oil and calcium oxide were used to create the synthetic soft particles. The precipitates were collected and analyzed with different techniques such as FTIR and GC-MS, to identify the main components which were then compared with the results of the previous study. Following this, specific attention was given to calcium methyl azelate as it was shown to be found in field fuel filters. A method using GC-MS was developed to be able to estimate the amount of soft particles by measuring calcium methyl azelate. The specified method proved to be adequate for future studies to evaluate the filtration efficiency of different filter materials against soft particles.
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| 4. |
- Pach, M., et al.
(author)
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An Investigation of the Degradation of Biodiesel Blends in a Heavy-Duty Diesel Engine
- 2022
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In: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191.
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Conference paper (peer-reviewed)abstract
- One way to reduce carbon dioxide emissions from the current heavy-duty vehicles fleet is to replace fossil fuel with renewable fuel. This can be done by blending so-called drop-in fuels into the standard diesel fuel. However, problems such as insoluble impurities may arise when the fuels are mixed. These precipitates, known as soft particles, can cause deposits in the fuel system, e.g., injectors and fuel filters, reducing the enginés performance. The most used drop-in fuel today is biodiesel which, is blended with different concentrations. To better understand how soft particles are formed in the vehiclés fuel system, the degradation of biodiesel blends in the engine has been investigated. This study explores biodiesel blendś degradation process by comparing the incoming fuel with the return fuel from a modern diesel engine to investigate how the fuel is affected by this process. The engine was run using different blends of biodiesel fuel. To investigate the degradation of the biodiesel, engine tests at low, medium, and high torque at two engine speeds was performed. Fuel samples were collected before and after the engine for comparison. The tested fuels were examined with different analytical techniques. Rancimat, ion chromatography, inductively coupled plasma atomic emission spectroscopy and total acid number. A filtration test method was developed to collect the soft particles from the tested fuels. The results showed that fuel properties from the fuel return in biodiesel blends with high biodiesel content were more affected compared to lower biodiesel blends. For the lower biodiesel blends both the oxidation stability (Rancimat) and the filterability improved after passing the fuel system in the engine. While for the high biodiesel content, Rancimat and filterability were reduced. In biodiesels blends lower than 10%v/v, the change in oxidation stability was positive and around 30h and for B100 the change in oxidation stability was negative around 5 to 10 h. The filterability of blends with high biodiesel content showed that these fuels were more affected by different engine conditions, whereas B30 showed the highest variation in filtration time. Indicating that B30 is the most sensitive fuel. No big change was seen in the acid number for any biodiesel blends and a correlation was seen with biodiesel content. Further, the concentration of short chain fatty acid seems to correlate with the oxidation stability of the fuel. Increasing the level of short chain fatty acids, the oxidation stability of the fuel decreases.
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| 5. |
- Pach, M., et al.
(author)
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Characterization of Internal Diesel Injector Deposits from Heavy-Duty Vehicles
- 2021
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In: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191.
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Conference paper (peer-reviewed)abstract
- Sustainable fuels can help to decrease carbon dioxide emissions in road transportation compared to standard fossil fuels. The most common sustainable fuels used today in heavy-duty applications are biodiesel and hydrogenated vegetable oil (HVO). Biodiesel and HVO are known as drop-in fuels since they are fuels that can be blended with standard diesel. However, due to changes in the chemical properties when the fuels are mixed, solubility problems in terms of precipitates may be formed. These insolubilities can lead to deposits in the fuel system, e.g., blocked fuel filters and internal injector deposits, and thus driveability problems. This study is a part of a project where the goal is to study the processes that cause the formation of deposits inside the injectors in heavy-duty vehicles. The deposits inside the injectors are known as internal diesel injector deposits (IDID). To study the formation of IDID, a number of injectors from heavy duty vehicles were collected from two different European markets: one market that uses biodiesel fuel and another that uses HVO as a drop-in fuel. A technique not previously used to identify IDID, namely pyrolysis GC-MS, proved successful in this regard, and FTIR and SEM-EDX methods were also used to characterise the deposits. The results showed that the composition of the IDID s from different markets differed. Metal soaps, inorganic salts and nitrogen compounds were found in the deposits taken from the injectors in the biodiesel drop-in market. The source of these components is believed to be degradation and contamination of the biodiesel. In addition, fuel additives such as corrosion inhibitors and detergents were found in the injectors from the market using HVO as a drop-in fuel. This could imply that the poor solvency of HVO can give problems in some additive combinations.
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