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This study investigates the characterization of the hydroxy-diesel fueled compression ignition engine under dual fuel (DF) mode on a stationary modified engine. Hydroxy gas (HHO) is supplied along with diesel at three different flow rates of 0.25, 0.50, and 0.75 lpm. A significant reduction in emission parameters was obtained in carbon monoxide, unburnt hydrocarbon and smoke emission as ~58%, ~60%, and ~49%, respectively under the DF mode (at 0.75 lpm HHO and 10 kg load). However, a slight increment in nitrogen oxides (NO X) emission is observed due to the O 2 contents in HHO gas. It increases the reaction temperature and results in increasing the NO X emission. The brake thermal efficiency and brake specific energy consumption also improved and found to be ~6.5% and ~6% at the optimized condition. Combustion analysis shows the rate of pressure rise increased due to quicker combustion and decreased combustion duration. A numerical simulation has been performed to optimize the engine load and HHO flow rate using the Hybrid Entropy-VIKOR technique. In addition, a good agreement has been found between simulation and experimental values for performance and emission parameters. The results can be further improved by optimizing the engine operating parameters, i.e., injection pressure, compression ratio, and injection timing in the near future. Overall it can be concluded the HHO can be considered as a prominent alternative fuel for the CI engine with increased efficiency and lower emissions. Image 1 • Engine performance parameters (BTE and BSEC) improved with the hydroxy energy share. • Significant reduction in HC, CO, and smoke emission was observed with the HHO addition. • ROPR, in-cylinder MGT, and NHRR improved for D+0.75HHO mixture. • The engine operating parameters were optimized using the hybrid Entropy-VIKOR approach. [ABSTRACT FROM AUTHOR]

Latest research on fuels focused on exploring better alternatives for compression ignition engines. A large number of studies reported that the properties of biodiesel are comparable with traditional diesel fuel, which makes it a suitable alternative source of energy. Among various available feedstocks, waste cooking oil is considered as the most viable source for biodiesel production. Apart from being economical, it also reduces waste disposal issues. High free fatty acids and water content in waste cooking oil cause the production of biodiesel difficult. In order to overcome this difficulty, two-step transesterification method is preferred for commercial-scale biodiesel production. Several factors like catalyst concentration, alcohol to oil molar ratio, reaction temperature, and time of reaction affect the yield of biodiesel. This article provides a comprehensive review of biodiesel production from waste cooking oil and its use in compression ignition engines. In this review, fatty acid composition, pre-treatment process, catalytic and non-catalytic approaches of biodiesel production with their advantages and limitations are included. The effect of transesterification reaction parameters on biodiesel yield is also covered. The high viscosity of biodiesel than diesel fuel causes an increase in brake specific fuel consumption and a decrease in brake thermal efficiency of engines. Significant reduction in CO, HC, PM, and smoke emissions are identified; however, NO X and CO 2 emissions found increased due to the oxygenating nature of biodiesel. Overall, it could be concluded that biodiesel produced from waste cooking oil serves as a cleaner and economical alternative source of fuel for compression ignition engines. [Display omitted] • Approximately 30% of per capita edible oil consumption is generated as waste. • Two-step transesterification is the most efficient method for biodiesel production. • Yield of biodiesel is most influenced by the type of catalyst and its concentration. • Brake specific fuel consumption increases due to poor atomization of biodiesel. • CO, HC, PM, and smoke emissions from engine exhaust are reduced significantly. [ABSTRACT FROM AUTHOR]

• A novel approach of cow-urine (gomutra) emulsification in diesel is explored. • 15% Cow-urine emulsification in diesel was found optimum. • Significant 13.2% improvement in brake thermal efficiency was observed. • Water and urea content of the GMD emulsion resulted in reduced exhaust emissions. • NO x and smoke emissions got reduced up to 31.8% and 36.9% respectively. Apart from the various emission reduction strategies, a novel concept of cow-urine emulsification in diesel has been explored in this study. In India, cow urine is easily and readily available as gomutra distillate. It constitutes of around 95% water and exhibits the benefits of water emulsification to improve the brake thermal efficiency. Additionally, it consists of urea which works as a reducing agent and significantly cuts-down the NO x emissions. Sodium, magnesium, calcium and potassium present in the cow-urine are also expected to enhance the fuel properties as found in various other researches. Emulsions containing 5%, 10%, 15% and 20% (v/v) cow-urine were tested on a stationary C.I. engine. The 15% emulsion was found to be optimum with a remarkable increase in BTE reaching up to 24.8% as compared to 21.9% with base diesel. In emissions, NO x and smoke got reduced by maximum up to 31.8% and 36.9% respectively. At lower loads, the CO emissions were found to be increased but at higher loads, it was also decreased. No significant variation in HC emissions was observed. Overall, cow-urine emulsified diesel fuel was found to be an energy-efficient and cleaner alternative fuel for stationary C.I. engine application. [ABSTRACT FROM AUTHOR]

• Classification of biodiesel generations on the basis of the type of feedstocks is covered. • Botanical description and growth condition requirements of jatropha are discussed. • Physicochemical properties and fatty acid profile of jatropha biodiesel are analyzed. • Production of biodiesel from jatropha oil with different techniques is summarized. • Performance and emissions characteristics of C.I. engine fuelled with jatropha biodiesel are reviewed. Due to limited reserves of conventional fossil fuels and their negative impact on global climate and human health, researches are focused to find the alternate energy substitute. Comparable properties of biodiesel make it one of the most promising alternatives of conventional diesel fuel. Jatropha curcas oil (non-edible oil) belongs to the second-generation of biodiesel. In this review, the physicochemical properties, fatty acids distribution, stability of jatropha oil are discussed in detail. The change in fatty acid profile affects the fuel properties, performance and emissions of diesel engines operated on jatropha biodiesel. Oxidation stability of jatropha biodiesel is poor due to the high amount of unsaturated fatty acids. Blending, thermal cracking, micro-emulsification, and transesterification are four basic approaches for production of biodiesel. Transesterification is the most adoptive method due to less expensive operation and high product yield. This article also highlighted the performance and emissions of compression ignition engines operated on jatropha biodiesel and its blends. The lower calorific value of jatropha biodiesel is responsible for the decrease in brake thermal efficiency and an increase in brake specific fuel consumption. High availability of oxygen in jatropha biodiesel reduces HC, CO, and PM emissions, while NOx emission increases significantly. This article provides the most of details of optimum parameters for jatropha biodiesel production and its efficient use in diesel engines. [ABSTRACT FROM AUTHOR]