Search

Diethylene glycol dimethyl ether (DGM), also known as diglyme, has a very high cetane number with fuel-bound oxygen of up to 36%, it has strong potential to reduce diesel emissions. This work is an investigation of the turbocharged diesel engine’s emissions and performance parameters using coconut biodiesel-diglyme-diesel blends. Coconut biodiesel was used as an oxygenated fuel, while DGM was utilised as an oxygenated additive for its excellent cetane number and higher fuel-bound oxygen. The reason for adding diglyme to coconut biodiesel blends is to study the influence of cetane number and fuel-bound oxygen on performance, combustion and emission characteristics. There were five fuels tested in this study. To compare the performance, combustion and emissions data, a regular diesel was used as a base fuel. The neat diesel (100% diesel) and the neat coconut biodiesel (100% coconut biodiesel) were designated as diesel and Ox4 respectively. Blend of 70% diesel + 30% coconut biodiesel is abbreviated as Ox1, 70% diesel + 20% coconut biodiesel + 10% diglyme blend is abbreviated as Ox2, and 70% diesel + 10% coconut biodiesel + 20% diglyme blend is labelled as Ox3. All blending percentages were based on a volume basis. Engine experiments were performed with an unmodified Cummins 6-cylinder common rail diesel engine. The engine was fitted with precision measuring instruments. Using GT-Power, a one-dimensional (1-D) model was developed to examine some key performance parameters with those of experimental data. Most of the performance results show the variations between experimental and simulation data were within 10%.

Essential oils are mostly used in aromatherapy and their popularity has grown rapidly for the last decade. However, the industry has a substantial low-value waste stream, because downstream industries require therapeutic-grade oil. These waste stream oils can be used in the transport and agricultural sectors. This study investigated the influence of various essential oil blends on the emission characteristics of a multi-cylinder diesel engine. Orange, eucalyptus and tea tree oil were blended with diesel at 5% and 10% by volume, neat diesel and a 10% waste cooking biodiesel-diesel blend were also tested for comparison. The major constituents of orange oil and eucalyptus oil are limonene and 1,8-cineole respectively, and the main constituents of tea tree oil are terpinen-4-ol, γ-terpinene and α-terpinene. Orange oil contains negligible amounts of oxygen, whereas eucalyptus oil and tea tree oil contain 8.4% and 5.4% respectively. Compared to neat diesel, all the essential oil blends exhibited similar or slightly higher density, similar heating value, lower viscosity, flash point, and cetane number, and higher surface tension. However, only orange oil and eucalyptus oil blends exhibited oxidation stability above the minimum standards. Interestingly, blending eucalyptus oil increased the oxidation stability of diesel. Tea tree oil blends emitted the most carbon monoxide (CO) while orange oil and eucalyptus oil blends emitted the least CO and nitrogen oxide (NOX). Although eucalyptus oil and tea tree oil blends contain similar levels of oxygen, they exhibited opposite NOX emission trends, which might be attributed to the dissimilar and complex bonding of oxygen molecules into the structures. Particle number emission of essential oils were load dependent, however, all essential oil belnds emitted higher particulate mass at all loads.

The study investigated the key factors that influence the formation of diesel nitrogen oxides (NOx) ethanol–diesel (e-diesel) blends. In the first phase of this investigation, a thermodynamic model was developed to simulate and analyse the different parameters that affect the NOx formation. GT-Power was used to develop the model. ANSYS was also used to compare the results of GT-Power. The simulated (GT-Power and ANSYS) data of cylinder pressure was validated with experimental in-cylinder pressure data. For the 1-D model development, a 4-cylinder diesel engine with a compression ratio of 22.6 was chosen. The engine speed was differed from 1400 rpm to 2400 rpm; the injection timing was varied from 30° before top dead centre (BTDC) to 20° after top dead centre (ATDC), the inlet air temperature were changed from 293 K to 393 K, and the injected masses were ranged from 32 mg to 92 mg. Also, the energetic and exergetic parameters with respect to oxygen ratio and equivalence ratio were investigated. For this investigation, three ethanol blends and neat diesel fuel were used. The first blend was prepared with 10% ethanol and 90% diesel (E10), Similarly, the E20, E30 were made. The simulated data indicated that higher in-cylinder combustion temperature, inlet temperature, injected mass, and advanced injection timing were the principal causes for higher NOx formation. Interesting to note that among the four fuels, all three blends showed less NOx relative to neat diesel. The energy and exergy parameters with oxygen ratio show insignificant variations among the four fuels.

In this study, the biodiesel properties and effects of blends of oil methyl ester petroleum diesel on a CI direct injection diesel engine is investigated. Blends were obtained from the marine dinoflagellate Crypthecodinium cohnii and waste cooking oil. The experiment was conducted using a four-cylinder, turbo-charged common rail direct injection diesel engine at four loads (25%, 50%, 75% and 100%). Three blends (10%, 20% and 50%) of microalgae oil methyl ester and a 20% blend of waste cooking oil methyl ester were compared to petroleum diesel. To establish suitability of the fuels for a CI engine, the effects of the three microalgae fuel blends at different engine loads were assessed by measuring engine performance, i.e. mean effective pressure (IMEP), brake mean effective pressure (BMEP), in cylinder pressure, maximum pressure rise rate, brake-specific fuel consumption (BSFC), brake thermal efficiency (BTE), heat release rate and gaseous emissions (NO, NOx,and unburned hydrocarbons (UHC)). Results were then compared to engine performance characteristics for operation with a 20% waste cooking oil/petroleum diesel blend and petroleum diesel. In addition, physical and chemical properties of the fuels were measured. Use of microalgae methyl ester reduced the instantaneous cylinder pressure and engine output torque, when compared to that of petroleum diesel, by a maximum of 4.5% at 50% blend at full throttle. The lower calorific value of the microalgae oil methyl ester blends increased the BSFC, which ultimately reduced the BTE by up to 4% at higher loads. Minor reductions of IMEP and BMEP were recorded for both the microalgae and the waste cooking oil methyl ester blends at low loads, with a maximum of 7% reduction at 75% load compared to petroleum diesel. Furthermore, compared to petroleum diesel, gaseous emissions of NO and NOx, increased for operations with biodiesel blends. At full load, NO and NOx emissions increased by 22% when 50% microalgae blends were used. Petroleum diesel and a 20% blend of waste cooking oil methyl ester had emissions of UHC that were similar, but those of microalgae oil methyl ester/petroleum diesel blends were reduced by at least 50% for all blends and engine conditions. The tested microalgae methyl esters contain some long-chain, polyunsaturated fatty acid methyl esters (FAMEs) (C22:5 and C22:6) not commonly found in terrestrial-crop-derived biodiesels yet all fuel properties were satisfied or were very close to the ASTM 6751-12 and EN14214 standards. Therefore, Crypthecodinium cohnii- derived microalgae biodiesel/petroleum blends of up to 50% are projected to meet all fuel property standards and, engine performance and emission results from this study clearly show its suitability for regular use in diesel engines.

The principal objective of this study was to investigate the effect of fuel oxygen on diesel particulate mass and number emissions using two different oxygenated blends. Jatropha biodiesel (JBD) and diglyme were used as oxygenates. Marine gas oil (MGO) was chosen as base fuel for its diesel like properties and frequent use in maritime transportations. Tests were conducted with a diesel engine at four different loads. Two blends were made maintaining same oxygen content in the blends. The diglyme blend is termed as Ox1, while JBD blend as Ox2. A dilution tunnel was used to collect the particle mass on glass fiber filter, while a scanning mobility particle sizer (SMPS) was used to determine the particle number concentrations. Smoke, carbon monoxide (CO), total unburnt hydrocarbon (THC), and oxides of nitrogen (NOx) were also measured. Experimental results showed that at high loads, for both oxygenated blends (Ox1, Ox2), fine particle number concentrations in the accumulation mode (AM) (peaking at around 73 nm) decreased markedly, compared to the reference MGO. However, the number concentrations, for the Ox2, in the nucleation mode (NM) (peaking at around 15 nm) blend increased significantly at all loads. The total particulate matter (TPM), which was measured by gravimetric method, was lower for both Ox1 and Ox2 compared to MGO. Ox1 and Ox2 also reduced CO, THC and smoke emissions. NOx emissions and exhaust temperatures were identical with the three blends. No significant changes in BSFC, brake thermal efficiency, CO2 and gas pressures were observed among the three fuels. (C) 2011 Elsevier Ltd. All rights reserved.