Biodiesel has been accepted as a clean and an eco-friendly green diesel fuel by the entire world. In India, various non-edible oils have been tested for exploring their suitability as a fuel in diesel engines. In the north eastern states of India, many oil bearing seeds such as Koroch (a variety of Pongamia glabra ), Nahar ( Mesua ferrea ), Terminalia ( Terminalia belerica Robx ), Kutkura ( Meyna spinosa Roxb ), Amari ( Amoora Wallichii King ), Yellow oleander ( Thevetia peruviana ) and others are found in abundance. In this article, the Yellow oleander seed oil (YOSO) has been investigated for biodiesel production and characterization. The oil content in Yellow oleander seed is found to be 63.87%. The free fatty acid (FFA) content in YOSO is measured, and is found to be 32.0%; hence the two-step acid-base catalysis transesterification process has been adopted for producing biodiesel from the YOSO. YOSO contains 5.03% palmitic, 6.92% stearic, 48.14% oleic and 31.37% linoleic acid. The density, calorific value and kinematic viscosity of Yellow oleander fatty acid methyl ester (YO-FAME) are 879.7 kg/m 3 , 40.159 MJ/kg and 4.63 mm 2 /s respectively. Most of the fuel properties of YO-FAME meet ASTM D6751 and EN 14214 biodiesel standards. The YO-FAME exhibits a low sulphur content of 13.0 ppm and a high cetane number of 58.3. Fire point and pour point of YO-FAME were found to be 158°C and 5°C respectively. The physio-chemical properties of YO-FAME has been compared with FAME of Yellow oleander, Ratanjot ( Jatropha curcus ), Terminalia ( Terminalia belerica Robx. ) and Nahar ( Mesua ferrea ).

Research was conducted to observe the correlation of ignition delay, combustion delay, the negative temperature coefficient region (NTCR), and the low temperature heat release region (LTHR), in a constant volume combustion chamber (CVCC) in relation to blended amounts of iso-paraffinic kerosene (IPK) by mass with Jet-A and their derived cetane numbers (DCN). The study utilizes the ASTM standard D7668-14.a in a PAC CID 510 CVCC. The DCN was calculated using the ignition delay and combustion delay measured over 15 combustion events. The fuel blends investigated were 75%Jet-A blended with 25%IPK, 50%Jet-A with 50%IPK, 25%Jet-A with 75%IPK, neat Jet-A, and neat IPK. The ignition delay of neat Jet-A and IPK was found to be 3.26ms and 5.31ms, respectively, and the combustion delay of the fuels were 5.00ms and 17.17 ms, respectively. The ignition delay for 75Jet-A25IPK, 50Jet-A50IPK, 25Jet-A75IPK, fuel blends were found to be 3.5ms, 3.8ms, and 4.2ms, respectively. The combustion delay between the 75Jet-A25IPK, 50Jet-A50IPK, 25Jet-A75IPK, blends are 5.8ms, 7.0ms, and 9.4ms, respectively. The DCNs for 75Jet-A25IPK, 50Jet-A50IPK, 25Jet-A75IPK 43.1, 38.7, and 33.5, respectively. The DCN of the fuel blends compared to neat Jet-A was lower by 10.16% for 75Jet-A25IPK, 19.37% for 50Jet-A50IPK, 30.50% for 25Jet-A75IPK and 46.03% for neat IPK. Blends with larger amounts by mass of IPK resulted in extended ignition and combustion delays. It is concluded that the fuels that have larger amounts of IPK blended within them have extended NTC regions, LTHR regions, and decreased ringing intensity during combustion.

Microemulsions are sustainable alternatives to fos sil fuels, which could possibly be used without any modifications in current engines and storage-transportation-supply infrastructure. Our current work attempts to examine the usability of butanol-diesel-water microemulsion fuels in a diesel engine. A small percentage of water is desirable, as it reduces the NO x and smoke emissions. The microemulsion regions were mapped out in ternary phase diagrams, and the fuel was characterized as per ASTM D975, and further examined for its performance in a diesel engine. The formulated microemulsions satisfied the ASTM standards, and had properties (density, viscosity, flash points, cloud points, copper strip corrosion rating, sulfur content, and ash percent) close to those of neat diesel. The percentage change in property ε was calculated as [|(ε diesel − ε microemulsion )|/ε diesel ] × 100. The calorific values for the microemulsion fuels showed a maximum reduction of 8.31% as compared to that of neat diesel. The brake thermal efficiency, however, increased by 15.38% for the same, with respect to the value for neat diesel (2% higher overall efficiency of the engine). The brake specific fuel consumption was also lowered by 5.04%, and the maximum reduction in emissions of CO, unburnt HC, CO 2 , and NO x were observed to be 53.48%, 67.40%, 30.82%, and 41.72%, respectively, relative to those of neat diesel. The present experimental investigations thus suggest that the microemulsions could be used as a sustainable cleaner alternative to diesel.

The goal of this investigation is to compare the validation of Sasol-IPK and its surrogate fuel in the IQT and in an actual diesel engine. The surrogate fuel is composed of three components (46% iso-cetane, 44% decalin and 10% n-nonane on a volume basis). IQT experiments were conducted as per ASTM D6890-10a. Engine experiments were conducted at 1500 RPM, two engine loads, and two injection timings. Analysis of the ignition delay, peak pressure, peak RHR and other combustion phasing parameters, showed a closer match in IQT than in the diesel engine. This investigation suggests that validation in a single cylinder diesel engine should be a part of the surrogate validation, particularly for low ignition quality fuels.

The auto-ignition process plays a major role in the combustion, performance, fuel economy and emission in diesel engines. The auto-ignition quality of different fuels has been rated by its cetane number (CN) determined in the CFR engine, according to ASTM D613. More recently, the Ignition Quality Tester (IQT), a constant volume vessel, has been used to determine the derived cetane number (DCN) to avoid the elaborate, time consuming and costly engine tests, according to ASTM D6890. The ignition delay period in these two standard tests and many investigations has been considered to be the time period between start of injection (SOI) and start of combustion (SOC). The ignition delay (ID) values determined in different investigations can vary due to differences in instrumentation and definitions. This paper examines the different definitions and the parameters that effect ID period. In addition the activation energy dependence on the ID definition is investigated. Furthermore, results of an experimental investigation in a single-cylinder research diesel engine will be presented while the charge density is kept constant during the ID period. The global activation energy is determined and its sensitivity to the charge temperature is examined.

This study investigates the combustion characteristics of cotton seed fatty acid methyl esters (FAME), with C100 (100% cotton seed biodiesel) and C20 (20% cotton seed biodiesel, 80% ultra-low sulfur diesel #2), in a direct injection diesel engine and compares the results with ultra-low sulfur diesel #2 (ULSD#2). The dynamic viscosity of C100 was found to meet the American Society for Testing and Materials (ASTM) standard. The lower heating value obtained for C100 was 37.7 MJ/kg, compared to 42.7 MJ/kg for ULSD#2. ULSD#2 and C100 displayed ignition delays of 9.6 crank angle degrees (CAD) and 7 CAD representing 1.14 ms and 0.83 ms respectively and a combustion time of 4ms (35 CAD) at 1400 rpm and 8 bar indicated mean effective pressure (IMEP) (100% load). The apparent heat release of the tested fuels at 8 bar IMEP showed both a premixed and diffusion phase and produced maximum values of 122 and 209 J/CAD for C100 and ULSD#2 respectively, with a decreasing trend occurring with increase in percentage of FAME. The 50% mass burnt (CA50) for 100% biodiesel was found to be 3 CAD advanced, compared with ULSD#2. The maximum total heat flux rates showed a value of 3.2 MW/m 2 for ULSD#2 at 8 bar IMEP with a 6% increase observed for C100. Mechanical efficiency of ULSD#2 was 83% and presented a 5.35% decrease for C100, while the overall efficiency was 36% for ULSD#2 and 33% for C100 at 8 bar IMEP. The nitrogen oxides (NOx) for C100 presented an 11% decrease compared with ULSD#2. Unburned hydrocarbons value (UHC) for ULSD#2 was 2.8 g/kWh at 8 bar IMEP, and improved by 18% for C100. The carbon monoxide (CO) emissions for C100 decreased by 6% when compared to ULSD#2 at 3 bar IMEP but were relatively constant at 8 bar IMEP, presenting a value of 0.82 g/kWh for both fuels. The carbon dioxide (CO 2 ) emissions for C100 increased by 1% compared with ULSD#2, at 3 bar IMEP. The soot value for ULSD#2 was 1.5 g/kWh and presented a 42% decrease for C100 at 8 bar IMEP. The results suggest a very good performance of cotton seed biodiesel, even at very high content of 100%, especially on the emissions side that showed decreasing values for regulated and non-regulated species.

HCCI combustion is highly dependent on in-cylinder thermal conditions favorable to auto-ignition, for a given fuel. Fuels available at the pump can differ considerably in composition and auto-ignition chemistry, hence strategies intended to bring HCCI to market must account for the fuel variability. To this end, a test matrix consisting of eight gasoline fuels composed of blends made solely from refinery streams was investigated in an experimental, single cylinder HCCI engine. The base compositions were largely representative of gasoline one would expect to find across the United States, although some of the fuels had slightly lower average octane values than the ASTM minimum specification of 87. All fuels had 10% ethanol by volume included in the blend. The properties of the fuels were varied according to research octane number (RON), sensitivity (S=RON−MON) and the volumetric fractions of aromatics and olefins. For each fuel, a sweep of the fuelling was carried out at each speed from the level of instability to excessive ringing to determine the limits of HCCI operation. This was repeated for a range of speeds to determine the overall operability zone. The fuels were kept at a constant intake air temperature during these tests. The variation of fuel properties brought about changes in the overall operating range of each fuel, as some fuels had more favorable low load limits, whereas others enabled more benefit at the high load limit. The extent to which the combustion event changed from the low load limit to the high load limit was examined as well, to provide a relative criterion indicating the sensitivity of HCCI range to particular fuel properties.

Microalgae is currently receiving strong consideration as a potential biofuel feedstock to help meet the advanced biofuels mandate of the 2007 Energy Independence and Security Act because of its theoretically high yield (gallons/acre/year) in comparison to current terrestrial feedstocks. Microalgae lipids can be converted into a variety of biofuels including fatty acid methyl esters (e.g. biodiesel), renewable diesel, renewable gasoline or synthetic paraffinic aviation kerosene. For algal methyl ester biodiesel, fuel properties will be directly related to the fatty acid composition of the lipids produced by the given microalgae strain. Several microalgae species under consideration for wide scale cultivation, such as Nannochloropsis , produce lipids with fatty acid compositions containing substantially higher quantities of long chain-polyunsaturated fatty acids (LC-PUFA) in comparison to terrestrial feedstocks. It is expected that increased levels of LC-PUFA will be problematic in terms of meeting all of the current ASTM specifications for biodiesel. For example, it is well known that oxidative stability decreases with increasing levels of LC-PUFA. However, these same LC-PUFA fatty acids, such as eicosapentaenoic acid (EPA: C20:5) and docosahexaenoic acid (DHA: C22:6) are known to have high nutritional value thereby making separation of these compounds economically attractive. Given the uncertainty in the future value of these LC-PUFA compounds and the economic viability of the separation process, the goal of this study was to examine the oxidative stability of algal methyl esters with varying levels of EPA and DHA. Tests were conducted using a Metrohm 743 Rancimat with automatic induction period determination following ASTM D6751 and EN 14214 standards, which call for induction periods of at least 3 hours and 6 hours, respectively. Tests were conducted at a temperature of 110°C and airflow of 10 L/h with model algal methyl ester compounds synthesized from various sources to match the fatty acid compositions of several algae strains subjected to varying removal amounts of roughly 0 to 100 percent LC-PUFA. In addition, tests were also conducted with real algal methyl esters produced from multiple sources. The bis-allylic position equivalent (BAPE) was calculated for each fuel sample to quantify the level of unsaturation. The induction period was then plotted as a function of BAPE, which showed that the oxidative stability varied exponentially with the amount of LC-PUFA. The results suggest that removal of 45 to 65 percent of the LC-PUFA from Nannochloropsis -based algal methyl esters would be sufficient for meeting existing ASTM specifications for oxidative stability.

The project investigates the effects of peanut FAME on diesel engine combustion and thermal efficiency. The cold flow properties and viscosity were tested and were found that the cloud point (CP) and pour point (PP) of peanut FAME were 17°C and 8°C respectively, and was able to achieve CP of 0°C when blended 20:80 (wt%) with diesel No. 2 (P20). The dynamic viscosity of peanut FAME was 4.2cP (P100) and 2.85cP at 54°C (P20), both fuels are within the ASTM standard for biodiesel. The lower heating value (LHV) of peanut FAME was 37.10MJ/kg (P100) and 41.3MJ/kg (P20) compared to 41.7MJ/kg for diesel No.2 (D100), which supports the usage of peanut FAME in compression ignition engines. At residence time of 5ms from start of injection, P50 has shown positive combustion characteristics with ignition delay of 1.072ms at 2600rpm, 4.78 bmep (100% load). The P50 heat release displayed similar development compared with diesel No. 2, where premixed phase combined with diffusion combustion and reaching a maximum of 20.0J/CAD, which was higher than 17.5J/CAD for D100. Convection flux for both D100 and P50 had values of 1.4MW/m 2 . The total heat flux, calculated by Annand model, produced maximum values of 2.1MW/m 2 for D100 compared with 2.3MW/m 2 for the P50. The mechanical efficiency was only a 4% loss when observing the transition from D100 to P50. These findings support peanut FAME as a viable option when blended and used with diesel engines in order to meet the standards set forth by the RSF-2 and EISA allowing the U.S. to decrease foreign energy dependency and benefiting society through a cleaner burning fuel than is currently in use.

Biodiesel is a desirable alternative fuel for the diesel engine due to its low engine-out soot emission tendency. When blended with petroleum-based diesel fuels, soot emissions generally decrease in proportion to the volume fraction of biodiesel in the mixture. While comparisons of engine-out soot measurements between biodiesel blends and petroleum-based diesel have been widely reported, in-cylinder soot evolution has not been experimentally explored to the same extent. To elucidate the soot emission reduction mechanism of biodiesel, a single-cylinder optically-accessible diesel engine was used to compare the in-cylinder soot evolution when fueled with ultra-low sulfur diesel (ULSD) to that using a B20 biodiesel blend (20% vol/vol biodiesel ASTM D6751-03A). Soot temperature and KL factors are simultaneously determined using a novel two-color optical thermometry technique implemented with a high-speed CMOS color camera having wide-band Bayer filters. The crank-angle resolved data allows quantitative comparison of the rate of in-cylinder soot formation. High-speed spray images show that B20 has more splashing during spray wall impingement than ULSD, distributing rebounding fuel droplets over a thicker annular ring interior to the piston bowl periphery. The subsequent soot luminescence is observed by high-speed combustion imaging and soot temperature and KL factor measurements. B20 forms soot both at low KL magnitudes over large areas between fuel jets, and at high values among remnants of the fuel spray, along its axis and away from the bowl edge. In contrast, ULSD soot luminescence is observed exclusively as pool burning on the piston bowl surfaces resulting from fuel wall impingement. The soot KL factor evolution during B20 combustion indicates earlier and significantly greater soot formation than with ULSD. B20 combustion is also observed to have a greater soot oxidation rate which results in lower engine-out soot emissions. Measured soot temperatures near 1875K were similar for the two fuels for the duration of combustion. For both fuels, higher fuel injection pressure led to lower late-cycle soot KL levels. The trends of soot natural luminosity correlated well with the trends of soot KL factor, suggesting that relatively simple measurements of combustion luminosity may provide somewhat quantitative information about in-cylinder soot formation and oxidation. The apparent rate of heat release (ARHR) analysis under steady skip-fire conditions indicates that B20 combustion is less sensitive to wall temperature than that observed with ULSD due to a lesser degree of pool burning. B20 was found to have both a shorter ignition delay and shorter combustion duration than ULSD.

Low-sulfur “clean” diesel fuel has recently been mandated in the U.S. market. However, quality of diesel fuel, particularly the sulfur content, varies significantly in other parts of the world. Due to logistical issues in various theaters of operation, the Army is often forced to rely on local fuel supplies, which exposes vehicles to diesel fuel or jet fuel (JP8) with elevated levels of sulfur. Currently, modern diesel engines typically use cooled Exhaust Gas Recirculation (EGR) to meet emissions regulations. Using high sulfur fuels and cooled EGR has potential to lead to EGR cooler fouling and corrosion of engine components. Therefore, an experimental study has been setup to investigate the EGR heat exchanger condensate in a heavy duty diesel engine running on JP-8 fuel doped with 3512 ppm of sulfur. Gas was sampled from the EGR cooler and analyzed. A Condensate Collection Device (CCD) was developed and setup according to a modified ASTM 3226-73T standard, to perform analysis of sulfur condensate species of SO 2 and H 2 SO 4 in the EGR system. Results have shown that SO 2 values to have the highest concentration of gaseous sulfur species. SO 2 is also shown to increase as sulfur content in JP-8 increases, but not by the same order of magnitude. Results have also shown low levels of H 2 SO 4 from 2–5 ppm with negligible differences while varying sulfur content in JP-8, EGR levels of the engine, and condenser temperatures in the CCD. Due to suspicion that all sulfur has not been accounted for in experiments with the modified CCD, further experiments were performed using a Fourier Transform Infrared (FTIR) emissions bench for gaseous SO 2 emissions and a Differential Mobility Spectrometer (DMS) for particulate size spectrum analysis. FTIR results yielded similar results for gaseous SO 2 as the modified CCD with SO 2 levels increasing as sulfur content in fuel increases but not by the same order of magnitude. While the results from the DMS have shown that increasing sulfur content in JP-8 will increase the particle sizes in the particle size distribution curve. This also translates to an increase in PM mass concentration in the exhaust stream when sulfur content is increased in JP-8 on an engine with and without EGR.

In the past ten years diesel engine performance has significantly increased in terms of kilowatts/litre (kW/L). These higher power density outputs create higher thermal loads on the cooling system and associated seals. While compatibility of elastomers in high temperature coolants has been studied and reported, the inevitable impact of thermal cycling on these elastomers is not well documented. This study examines the effects of thermal cycling in three general coolant categories on three different elastomers commonly considered for sealing hot engine coolants. The elastomers, by ASTM D1418 designation, are HNBR, FKM Type 2, and FEPM. The coolants are an organic acid technology (OAT) coolant, a propylene glycol premix coolant, and a corrosion inhibited de-ionized water. Normal service applications are characterized by an indefinite number of shutdowns and startups. Testing was designed to simulate such service. Aging periods incorporated ongoing 24 hour cycles: a 16 hour period to heat up and operate at 150°C, and an 8 hour period to cool off to ambient. O-rings, a common seal design, were subject to axial and radial deformation during testing. The o-rings’ sealing attributes were examined after four, ten, twenty, and forty cycles. Elastomeric properties were evaluated, before and after cyclical aging, in accordance with ASTM D1414-94 (“Standard Test Methods for Rubber O-rings”) and D412-06a (“Standard Test Methods for Vulcanized Rubber … - Tension”). Compressive stress relaxation (CSR) was evaluated using an in-house procedure, comporting with ASTM D6147-94.

Over the past several years, there has been increased interest in alternative diesel fuels to control emissions and provide energy security. Biodiesel is a fuel that can be made from renewable biological sources such as vegetable oils and animal fats, has been recognized as an environment friendly alternative to mineral diesel. In present investigation, rice bran oil (non-edible) was transesterified to methyl ester and reaction conditions for transesterifcation process for rice bran oil were optimized. Various properties like viscosity, density, flash point, calorific value of the biodiesel thus prepared are characterized as per ASTM norms (ASTM D6751) and found comparable to diesel. Steady state engine dynamometer test at full throttle conditions have been carried out to evaluate the performance and emission characteristics of a medium duty transportation DI diesel engine. Engine was fuelled with various blends of rice-bran oil biodiesel (ROME) and mineral diesel ranging from 5% biodiesel to 100% biodiesel (5, 10, 20, 30, 50, and 100%). Performance and emission data were compared to the baseline data obtained using mineral diesel. Same engine without any hardware modification has been adopted for tests on all fuel blends. The results of this experimental investigation showed that biodiesel and biodiesel blends exhibited almost similar torque and power characteristics. Biodiesel blends up to 20% produced slightly higher torque and improved performance. Improvement in fuel conversion efficiency was found for lower concentration blends i.e. up to 20%. Lowest efficiency was found for 100% biodiesel blend. All the biodiesel blends emitted lower total hydrocarbon, carbon monoxide emissions and smoke opacity but slightly higher NO x emissions during the full throttle tests. Emission tests with all the fuel blends have also been carried out using European 13 MODE test (ECE R49) procedure. Drastic reduction in THC and CO and slight increase in NO x was observed.