Due to the finite stock of fossil fuels and its negative impact on the environment, many countries across the world are now leaning toward renewable sources energies like solar energy, wind energy, biofuel, hydropower, geothermal and ocean energy to ensure energy for the countries development security. Biodiesel is one kind of biofuel that is renewable, biodegradable and has similar properties of fossil diesel fuel. The aim of this paper is to provide the substantial information on biodiesel to the researchers, engineers and policy makers. To achieve the goal, this paper summarizes the information on biofuel development, feedstocks around the world, oil extraction technic, biodiesel production processes. Furthermore, this paper will also discuss the advantages of biodiesel compared to fossil fuel. Finally, the combustion behavior of biodiesel in an internal combustion engine is discussed and it will help the researchers and policy maker and manufacturer. To determine the future and goal of automotive technology the study found that, feedstock selection for biodiesel production is very important as it associates 75% production cost. Moreover, the test of fuel properties is very important before using in the engine which depends on the type of feedstocks, origin country, and production process. Most of the researchers reported that the use of biodiesel in diesel engine reduces engine power slightly but reduces the harmful emission significantly. Finally, the study concludes that biodiesel has the potential to be used as a diesel fuel substitute in diesel engines to solve the energy and environment crisis.

Production, characterization and performance of biodiesel as an alternative fuel in diesel engines – A review

Biofuels have grabbed the attention of engine researchers ever since the oil-crisis and escalating costs of petro-chemicals cropped up in the ׳70s. Ethanol and methanol were the most widely researched alcohols in IC engines. However, the last decade has witnessed significant amount of research in higher alcohols due to the development of modern fermentation processes using engineered micro-organisms that improved yield. Higher alcohols are attractive second/third generation biofuels that can be produced from sugary, starchy and ligno-cellulosic biomass feedstocks using sustainable pathways. The present work reviews the current literature concerning the effects of using higher alcohols ranging from 3-carbon propanol to 20-carbon phytol on combustion, performance and emission characteristics of a wide range of diesel engines under various test conditions. The literature is abound with evidence that higher alcohols reduce carcinogenic particulate emissions that are prevalent in diesel engines. NOx emissions either increased or decreased based on the domination of either cetane number or heat of evaporation. Brake specific fuel consumption (BSFC) of the engine usually suffered due to low energy content of alcohols. A notable feature is that the combination of higher alcohols (like butanol or pentanol), high exhaust gas recirculation (EGR) rates and late injection timing enabled low temperature combustion (LTC) in diesel engines that can simultaneously reduce smoke and NOx emissions with improved engine efficiency. It can be concluded that higher alcohols reduce smoke emissions with their fuel-borne oxygen; enhance air/fuel mixing by offering long ignition delay and eventually replace fossil diesel (partially or wholly) to enable a clean and efficient combustion in compression-ignition engines. The chief thrust areas include developing mutant strains with higher yield, higher tolerance to toxic inhibition and low-cost substrates for fermentation. Further work is required in stipulating optimum blend-fuel characteristics and ensuring the long-term durability of the engines using these fuels.

Use of higher alcohol biofuels in diesel engines: A review

The increasing energy demand, surging oil prices, depleting oil reserves and environmental pollution problems associated with the use of fossil fuels have sparked renewed interest to find out clean alternative fuels. Alcohols such as methanol, ethanol and butanol are competitive alternative fuels due to their liquid nature, high oxygen contents, high octane number and their production from renewable biomass. In this review, the fuel properties of these alcohols are compared with conventional gasoline and diesel fuel. The comparison of fuel properties represents that butanol has the potential to overcome the problems associated with the use of methanol and ethanol. Progresses of their production from different sources are also introduced. Further, several techniques such as alcohol–diesel fuel blends and alcohol–diesel fuel emulsions are discussed, especially for lower alcohols, in order to use them in diesel engines. The effects of diesel–alcohol blends on the combustion, performance and emissions of diesel engines are also analyzed. It is examined that blending of alcohols, along with some CN improver, to diesel fuels can reduce diesel engine emissions without adverse impacts on the performance of diesel engines. These studies also reveal that butanol is a better alternative for diesel fuel due to its superior fuel properties and miscibility with diesel fuel than those of methanol and ethanol. Finally, some critical conclusions and future research directions are highlighted.

Advances in diesel–alcohol blends and their effects on the performance and emissions of diesel engines

The effect of nano-additives in diesel-biodiesel fuel blends: A comprehensive review on stability, engine performance and emission characteristics

Combined effect of influence of nano additives, combustion chamber geometry and injection timing in a DI diesel engine fuelled with ternary (diesel-biodiesel-ethanol) blends

In a normal diesel engine, about thirty percent of the total energy is rejected to the coolant. The low heat rejection concept is based on suppressing this heat rejection to the coolant and recovering the energy in the form of useful work. The purpose of this project is to increase the performance of the engine and improved the fuel economy resulting from coating those using partially stabilized zirconia (PSZ) thermal barrier coating for the performance in the diesel engine application. PSZ over the combustion chamber increases the temperature over the inside the combustion chamber and reduces the heat rejection to the atmosphere. Also an experimental investigation performed using a thermally insulated single cylinder direct injection water cooled diesel engine to evaluate the effect of coating on the cylinder head, piston top surface and the valve seats using PSZ to study the heat release, performance and emission characteristics. Studies are conducted for the engine with insulated head and piston and are compared with the base line engine. Based on the experimental studies it is concluded that a thermally insulated engine reduces the fuel consumption, improves the fuel efficiency. Also the emissions of HC and CO are reduced to a great extent while the emissions of NOX are increased due to higher combustion temperature. Various method of reducing NO X emissions will be adopted. Such as retarding the fuel injection timing, lowering the intake temperature, lower compression ratio. Thus, the LHR engine was tested for two different injection timings at Crank angle before top dead centre (BTDC), with the same engine Speeds and load conditions. The results showed that the BSFC and NOx emissions were reduced respectively by retarding the Injection timing.

Experimental investigation on a low heat rejection engine

Five non-edible vegetable oils (nerium, jatropha, pongamia, mahua & neem) were selected as alternate fuels and comparison analysis of performance and emission were done. A comparative analysis was done for methyl esters of different oils in blends with diesel of different proportions. It was observed that a diesel engine runs successfully on a blend of 20% biodiesel and 80% diesel fuel without affecting engine performance. Methyl ester from Nerium oil, with properties close to diesel, showed better performance and emission characteristics, followed by esters of jatropha, Pongamia, Mahua and Neem oils. Hence Nerium blend can be used in existing diesel engines without compromising the engine performance.

http://nopr.niscair.res.in/bitstream/123456789/12684/1/JSIR%2070%2810%29%20875-878.pdf

Biodiesels: an alternative renewable energy for next century

The increasingly strict restrictions being place on diesel engine emissions have the interest in alternative combustion concept. The dual fuel engine exhibits much better emission characteristics than a diesel engine whilst having similar efficiency. The dual fuel engine is investigated for their potential to achieve near zero nitrogen oxide (NOx) and soot-particle emissions. In both SI and diesel engines, the fuel must burn hot to ensure that the flame spreads rapidly through the combustion chamber before a new "charge" enters. In a dual fuel split injection engine, there is no need for a quickly spreading flame because combustion occurs throughout the combustion chamber. As a result, combustion temperatures can be lower, so emissions of nitrogen pollutants are negligible. The fuel is spread in low concentrations throughout the cylinder, so the soot emissions from fuel-rich regions in diesels are not present. As the method for reducing exhaust emissions from diesel engines, a homogenous charge diesel combustion technique is used where by a portion of fuel is supplied into the intake port to form homogenous pre mixture then the mixture is fed into the cylinder port before ignition of the diesel fuel, which is injected directly into the cylinder. The homogeneous pre mixture is prepared with the help of electronic fuel injection.

/pdf/experimental-investigation-on-performance-and-emission-2l5oz4abs5.pdf

Experimental investigation on performance and emission characteristics of dual fuel split injection of ethanol and diesel in CI engine

Faster depletion of fossil fuels, day to day increase of automotives and increasing cost of petroleum fuel triggered the interest of researchers to arrive at an alternative fuel which is most suitable to compression ignition engines. It is already proven that vegetable oil could be used in the compression ignition engines, by Mr. Rudolf Diesel, inventor of diesel engine in an exhibition. Further researchers reported few problems such as, clogging of fuel filter, nozzle choking, starting trouble during winter season etc., with prolonged usage of vegetable oil. Transesterification process is used for producing the NOME from raw Adelfa oil, to reduce its viscosity and to make it more suitable for compression ignitions without major modification. In this experimental work esterified Adelfa oil is being tested and compared with petroleum diesel. Adelfa (Nerium Oil Methyl EsterNOME) is blended with diesel by 20% by volume and various emission tests have been carried out. Promising results show a good sign of using A20 (Adelfa 20% by volume with diesel) as a fuel for compression engines.

/pdf/experimental-investigation-on-emission-parameters-of-45zbzrhlyr.pdf

Experimental investigation on emission parameters of transesterified Adelfa oil (Methyl Ester of Nerium Oil).

In order to find alternatives to fossil fuels and to solve the increasing pollution problems this study was conducted to investigate the effect of water-diesel emulsion fuel on performance and emission characteristics of a DI diesel engine. Also were studied the possibilities of increasing the water content in diesel and compared it with current issues. Moreover, the performance and emission characteristics of the diesel/water emulsion were compared with those of the petroleum diesel. For comparing the performance characteristics between water-diesel emulsion fuel and diesel fuel, the parameters such as brake thermal efficiency, indicated thermal efficiency, mechanical efficiency, and pressure versus crank angle diagram were considered. To study the emission characteristics, the oxides of nitrogen, smoke, unburned hydrocarbon and carbon monoxide were taken into account.

https://sphinxsai.com/2015/ch_vol7_no4/3/(1808-1813) v7n4.pdf

K. Annamalai

Papers

Experimental investigation on a low heat rejection engine

Biodiesels: an alternative renewable energy for next century

Experimental investigation on performance and emission characteristics of dual fuel split injection of ethanol and diesel in CI engine

Experimental investigation on emission parameters of transesterified Adelfa oil (Methyl Ester of Nerium Oil).

Reduction of Emissions by Diesel-Water Emulsion