Vallinayagam, R.; Vedharaj, S.; Sarathy, Mani; Dibble, Robert W.(ASME 2016 Internal Combustion Engine Fall Technical Conference, ASME International, 2016-12-01)[Conference Paper]
Direct use of naphtha in compression ignition (CI) engines is not advisable because its lower cetane number negatively impacts the auto ignition process. However, engine or fuel modifications can be made to operate naphtha in CI engines. Enhancing a fuel’s auto ignition characteristics presents an opportunity to use low cetane fuel, naphtha, in CI engines. In this research, Di-ethyl ether (DEE) derived from ethanol is used as an ignition enhancer for light naphtha. With this fuel modification, a “drop-in” fuel that is interchangeable with existing diesel fuel has been created.
The ignition characteristics of DEE blended naphtha were studied in an ignition quality tester (IQT); the measured ignition delay time (IDT) for pure naphtha was 6.9 ms. When DEE was added to naphtha, IDT decreased and D30 (30% DEE + 70% naphtha) showed comparable IDT with US NO.2 diesel. The derived cetane number (DCN) of naphtha, D10 (10% DEE + 90% naphtha), D20% DEE + 80% naphtha) and D30 were measured to be 31, 37, 40 and 49, respectively. The addition of 30% DEE in naphtha achieved a DCN equivalent to US NO.2 diesel.
Subsequent experiments in a CI engine exhibited longer ignition delay for naphtha compared to diesel. The peak in-cylinder pressure is higher for naphtha than diesel and other tested fuels. When DEE was added to naphtha, the ignition delay shortened and peak in-cylinder pressure is reduced. A 3.7% increase in peak in-cylinder pressure was observed for naphtha compared to US NO.2 diesel, while D30 showed comparable results with diesel. The pressure rise rate dropped with the addition of DEE to naphtha, thereby reducing the ringing intensity. Naphtha exhibited a peak heat release rate of 280 kJ/m3deg, while D30 showed a comparable peak heat release rate to US NO.2 diesel. The amount of energy released during the premixed combustion phase decreased with the increase of DEE in naphtha. Thus, this study demonstrates the suitability of DEE blended naphtha mixtures as a “drop-in” replacement fuel for diesel.
Vedharaj, S.; Vallinayagam, R.; Sarathy, Mani; Dibble, Robert W.(ASME 2016 Internal Combustion Engine Fall Technical Conference, ASME International, 2016-12-01)[Conference Paper]
In this research, the flow and ignition properties of vegetable oil (VO) are improved by blending it with diethyl ether (DEE). DEE, synthesized from ethanol, has lower viscosity than diesel and VO. When DEE is blended with VO, the resultant DEEVO mixtures have favorable properties for compression ignition (CI) engine operation. As such, DEEVO20 (20% DEE + 80% VO) and DEEVO40 (40% DEE + 60% VO) were initially considered in the current study. The viscosity of VO is 32.4*10−6 m2/s; the viscosity is reduced with the increase of DEE in VO. In this study, our blends were limited to a maximum of 40% DEE in VO. The viscosity of DEEVO40 is 2.1*10−6 m2/s, which is comparable to that of diesel (2.3*10−6 m2/s). The lower boiling point and flash point of DEE improves the fuel spray and evaporation for DEEVO mixtures. In addition to the improvement in physical properties, the ignition quality of DEEVO mixtures is also improved, as DEE is a high cetane fuel (DCN = 139). The ignition characteristics of DEEVO mixtures were studied in an ignition quality tester (IQT). There is an evident reduction in ignition delay time (IDT) for DEEVO mixtures compared to VO. The IDT of VO (4.5 ms), DEEVO20 (3.2 ms) and DEEVO40 (2.7 ms) was measured in IQT. Accordingly, the derived cetane number (DCN) of DEEVO mixtures increased with the increase in proportion of DEE.
The reported mixtures were also tested in a single cylinder CI engine. The start of combustion (SOC) was advanced for DEEVO20 and DEEVO40 compared to diesel, which is attributed to the high DCN of DEEVO mixtures. On the other hand, the peak heat release rate decreased for DEEVO mixtures compared to diesel. Gaseous emissions such as nitrogen oxide (NOX), total hydrocarbon (THC) and smoke were reduced for DEEVO mixtures compared to diesel. The physical and ignition properties of VO are improved by the addition of DEE, and thus, the need for the trans-esterification process is averted. Furthermore, this blending strategy is simpler and enables operation of straight run oils and fats in CI engine, replacing diesel completely.
Export search results
The export option will allow you to export the current search results of the entered query to a file. Different
formats are available for download. To export the items, click on the button corresponding with the preferred download format.
By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.
For anonymous users the allowed maximum amount is 50 search results.
To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export.
The amount of items that can be exported at once is similarly restricted as the full export.
After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.