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Technical Paper

Improvement in Combustion Characteristics of Biodiesel by Reforming with Cross-Metathesis Reaction

2021-09-21
2021-01-1205
The boiling point curve of fatty acid methyl esters (FAME), or biodiesel fuel, can be adapted to that of diesel fuel by breaking FAME down into a low-molecular structure using a cross-metathesis reaction with a short-chain olefin. Reformulated FAME by a metathesis reaction consists mainly of medium-chain olefins and fatty acid methyl esters. In the present study, the engine performance and exhaust emissions from reformulated FAME were investigated through engine bench tests. Surrogate fuels made from typical chemical components of reformulated FAME were used to clarify the effects of respective components upon combustion. Surrogate fuels were made by mixing 1-decene, 1-tetradecene, methyl laurate, methyl palmitate, and methyl oleate to simulate the boiling point, oxygen mass concentration, and calorific value of reformed biodiesel of waste cooking oil methyl ester (WME). A single-cylinder diesel engine equipped with common-rail-type injection system was used.
Journal Article

Effect of Additives in Various Biodiesels and Their Blends on Cold Flow Properties, Oxidation Stability and Diesel Exhaust Emissions

2013-10-14
2013-01-2660
The objective of this study was to obtain an improved understanding of the effects of the simultaneous use of cold flow improver (CFI) and antioxidant on the cold flow properties, oxidation stability and diesel exhaust emissions of various biodiesels and biodiesel blends. Cold flow properties were evaluated by assessing the cloud point (CP) and pour point (PP) values, as well as from the results of the cold soak filtration test (CSFT). Oxidation stability was also determined by measuring the peroxide induction period (IP). The neat biodiesels (B100) derived from soybean oil(SME), Jatropha curcus oil(JME), rice bran oil(RBME), palm oil(PME) and waste cooking oil(WME), and biodiesel blends with JIS No.2 diesel fuel were tested. A CFI and antioxidant specially designed for use in biodiesel fuels were employed during the work. The experimental data demonstrated that the addition of antioxidant had no effect on either the CP or PP values.
Technical Paper

Experimental Study of a Dual-Fuel Diesel Engine with Biodiesel and Low-Calorie Gas Fuels

2007-07-23
2007-01-2026
The experimental study has been carried out on a diesel engine dual-fueled by wood-pyrolysis gas and biodiesel fuel. Wood-pyrolysis gas was simulated by a low-calorie mixed gas (LCG), which consists of hydrogen, methane and inert gas. Effects of LCG/biodiesel ratio, biodiesel injection-timing, and gas-fuel composition were examined. Obtained results show that under a constant-torque condition, an increase in gas fuel consumption causes a decrease in a brake thermal efficiency due to a decrease in combustion efficiency and specific heat ratio. Also, NOx emission in exhaust gas is decreased by increase in gas fuel consumption under the low load condition, while it shows no change under the relatively high load condition. In addition, an early injection of biodiesel is effective to reduce carbon monoxide emission due to increase in combustion pressure and temperature.
Technical Paper

Regression Equations for Predicting the Cetane Number of Biodiesel Fuel Based on Fuel Composition and Properties

2011-08-30
2011-01-1941
This study derives regression equations for predicting the cetane number of biodiesel fuels based on chemical analysis data. For conducting the regression analysis, 34 fuel samples with a wide variety of ignition qualities were made by mixing five kinds of biodiesels and five kinds of fatty acid methyl ester (FAME) reagents. The relationship between the cetane number, measured in a constant-volume combustion chamber, and fuel properties such as iodine value, saponification number, and boiling point, was investigated. Based on the results, four regression equations were proposed and their accuracies were compared. The results show that the regression equation based on fuel composition gives a cetane number with high accuracy, whereas it can be only be approximately predicted from the iodine value.
Technical Paper

Suitability of 2-Ethylhexyl Esters from Plant Oils in Diesel Engines

2012-09-10
2012-01-1581
The suitability of caprylic (C8:0), lauric (C12:0), and palmitic (C16:0) acid 2-ethylhexyls derived from palm/coconut oil in diesel engine was evaluated. The pour point of each compound was approximately 40°C lower than that of the corresponding methyl ester due to the ethyl branch in the alcohol. All compounds possessed high oxidation stability, high lubricity, and a high cetane number. Engine bench test results demonstrated that 2-ethylhexyl laurate and palmitate result in shorter ignition delays compared to gas oil. The short ignition delays suppressed initial premix-like combustion. As a result, high brake thermal efficiency with low combustion noise was achieved. Furthermore, both laurate and palmitate produced less NOx emissions and less unburned gaseous emissions.
Technical Paper

A High-Pressure Diesel Fuel Injection System Using Spool Acceleration and Oil Hammering

1993-03-01
930599
In diesel engines, high-pressure fuel injection is very effective to reduce emissions of particulates and oxides of nitrogen. For this reason, all efforts have been directed to develop suitable high-pressure injection systems. However, high-pressure injection often increases internal leakage of the working fluid, increases power for pumping, and is sometimes still short of injection pressures at lower engine speeds. To remove these faults, the present authors developed a fuel injection system named KD-3 that relies on a novel principle using oil hammering in a convergent pipeline. The dynamic behavior of the proposed system was analyzed by the method of characteristics and computer simulations. A prototype injection system was designed and tested with success. Using a source pressure of 20 MPa, this system boosts pressure well to higher than 120 MPa at the inlet of injection nozzle.
Technical Paper

Combustion and Emission Characteristics of Diesel Fuel Derived from Micro-Algal Oil on DI Diesel Engines with Common-Rail Type Injection System

2015-09-01
2015-01-1924
“Drop-in” biofuels have a high potential as an alternative to petro-fuels. Because drop-in biofuels are hydrocarbon fuel, there are no issues related to poor oxidation stability such as in FAME. Diesel fuel which is named “SoladieselRD” is liquid bio-hydrocarbon and is the hydro-treated oil of micro-algal triglyceride. In this study, the engine performance and exhaust emission characteristics using SoladieselRD were investigated and compared with those using petro-diesel fuel (gas oil). A test was conducted using a single-cylinder, water-cooled, direct-injection diesel engine with a common-rail type high-pressure injection system. From the experimental results, it was clear that the ignition delay of SoladieselRD is shorter than that of petro-diesel, and the trade-off relationship between PM and NOx emissions by SoladieselRD was better than that of gas oil.
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