A rising concern on the depletion of fossil fuel and its growing demand for global energy has promoted research on alternative renewable biofuel. Vegetable oil is marked to be a potential source of energy that can substitute fossil fuels because of its comparable properties to diesel fuel, it is renewable and it is readily available. However, the high viscosity of straight vegetable oil (SVO) limits its application in diesel engines. The high viscosity of SVO can lead to incomplete combustion and carbon deposit in the combustion chamber of an engine. Thus, the blending of SVO with other fuels is seen as an essential and feasible solution in mitigating the issue. In this review, the effects of SVO and its blends on engine performance and emissions are comprehensively studied. Research on the direct use of SVO and several blends such as vegetable oil-diesel blend, vegetable oil-alcohol blend and vegetable oil-alcohol-diesel blend on diesel engine over the last decade are discussed. From these studies, it is found that brake specific fuel consumption (BSFC) for all blends fall between that of SVO and diesel. SVO-diesel blends containing less than 50% SVO have comparable brake thermal efficiency (BTE) to that of diesel fuel. Generally, NOX emitted by SVO, SVO-diesel and SVO-alcohol blends are lower or comparable to that of diesel fuel. Meanwhile, ternary blends of SVO-diesel-alcohol are found to reduce smoke, especially at high load. It is found that CO and unburn HC emissions are vary depending on engine specification, dynamometer operating condition and types of vegetable oil used. Overall, SVO blends are found as potential sources of renewable energy to partially or fully replace diesel fuel.

Performance and emissions of straight vegetable oils and its blends as a fuel in diesel engine: A review

Energy demand, decreasing fossil fuel reserves, and health-related issues about pollutants have led researchers to search for renewable alternative fuels to either partially or fully replace fossil fuels. Among many alternative fuels, biodiesel became one of the most popular choices due to similar properties to that of conventional diesel. Biodiesel produces slightly lower brake thermal efficiency compared to that of conventional biodiesel, but has an advantage of reduced emissions of CO2, CO, HC, and smoke. However, biodiesel shows higher NOx emission which, when used in increased biodiesel market, may become a serious problem. Various strategies were attempted by different researcher to reduce NOx emissions. In this paper, various strategies, adapted for reducing NOx emissions of biodiesel fuel used in diesel engines for automobile applications, are reviewed and discussed. The strategies are grouped into three major groups, namely combustion treatments, exhaust after-treatments, and fuel treatme...

Various strategies for reducing Nox emissions of biodiesel fuel used in conventional diesel engines: A review

Biodiesel emulsions are considered one of the most promising alternatives to petrol fuels. The purpose of the present investigation is to study the performance characteristics and the exhaust emission characteristics of a diesel engine run on nanoparticle blended biodiesel emulsion fuel. The engine performance under biodiesel blended diesel fuel was similar to that of the diesel fuel but with higher fuel consumption mainly due to the reduced calorific value that ensued from mixing with biofuel. The biodiesel emulsion fuel was prepared by emulsification technique comprising 83% canola biodiesel, 15% water, and 2% surfactants (Span80 and Tween80) with the help of a mechanical agitator. The prepared biodiesel emulsion fuel was mixed with the cerium nanoparticles in a mass fraction of 50 parts per million (ppm) with the help of an ultrasonicator. The investigation was carried out in a constant-speed diesel engine. The cerium oxide acts as an oxygen-donating medium and also provides oxygen for the oxid...

Performance and Emission Characteristics of a Diesel Engine Using Cerium Oxide Nanoparticle Blended Biodiesel Emulsion Fuel

Biofuels based on vegetable oils offer the advantages of being sustainable, annually renewable sources of automobile fuel. Despite many years of improvement, use of vegetable-oil-based fuels still has issues, such as oxidation, the stoichiometric point, bio-fuel composition, antioxidants on degradation and the volume of oxygen compared to diesel. Thus, improvements in the emissions from diesel engines fueled by a blend of crude jatropha oil with diesel could be the requirement to meet the reduced emissions regulations in the future. The purpose of this study is to investigate the effects on the vehicle’s performance and exhaust emissions of the combustion process of blended
crude jatropha oil and palm oil with different ratios. The engine speed was varied from 1500~3000 rpm, the load test condition was varied from 0~100% using a Dynapack
chassis dynamometer and crude jatropha oil with a diesel blending ratio from 5~15vol% (CJO5~CJO15) was used. A decrease in HC emissions was found in the combustion
process as the ratio of the blend of crude jatropha oil with diesel was increased and also with nearly equal engine performance. The increase in the jatropha oil biodiesel
blending ratio promoted the reduction of HC, CO and CO2 emissions in the range 10vol% to 15vol% of the blends. The improvement in the combustion process with the higher blending ratio is expected to be strongly influenced by the oxygen contained in the blended crude jatropha oil.

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Performance and emissions characteristics of crude jatropha oil biodiesel blends in a diesel engine

This research work investigates the use of neat paradise tree oil in a 4-stroke natural aspirated direct injection compression ignition engine assisted with the help of superheated hydrogen (hydrogen in gaseous state or above its saturation temperature) as a combustion improver. The high calorific gaseous fuel hydrogen gas was used as a combustion improver and admitted into the engine during the suction stroke. A 4-stroke single cylinder Diesel engine was chosen and its operating parameters were suitably modified. Neat paradise tree oil was admitted through standard injector of the engine and hydrogen was admitted through induction manifold. Inducted superheated hydrogen was initiated the intermediate compounds combustion of neat paradise tree oil. This process offers higher temperature combustion and results in complete combustion of heavier molecules of neat paradise tree oil within shorter duration. The results of the experiment reveal that 40% higher NOx, 20% lower smoke, 5% lower CO, and 45% lower HC than that of neat paradise tree oil fuel operation and the admission of superheated hydrogen has improved the combustion characteristics of neat paradise tree oil. The investigation successfully proved that the application of neat paradise tree oil with 15% of hydrogen improver is possible under a regular Diesel engine with minimal engine modification.

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Emission estimation of neat paradise tree oil combustion assisted with superheated hydrogen in a 4-stroke natural aspirated DICI engine

The objective of this study is to compare the engine performance and emission results of biodiesel derived from Jatropha oil when applied in different proportions in a stationary diesel engine without any engine modifications. A single cylinder four stroke diesel engine was tested at various loads with the blended fuel at the rated speed of 1500 rpm. Esterified Jatropha oil and diesel blends having 10%, 20%, 30%, 40% and 50% Jatropha oil on volume basis and pure diesel were used as fuel. Engine performance with pure diesel was also evaluated for comparison. An AVL 5 gas analyzer and a smoke meter were used for the measurements of exhaust gas emissions. Engine performance (specific fuel consumption, brake thermal efficiency, and exhaust gas temperature) and emissions (HC, CO, CO2, NOX and Smoke Opacity) were measured to evaluate and compute the behaviour of the diesel engine running on biodiesel. The results show that the brake thermal efficiency of diesel is higher at all loads followed by blends of Jatropha oil and diesel. Experimentally the maximum brake thermal efficiency and minimum specific fuel consumption were found for blends upto 20% Jatropha oil at all loads among the blends. The specific fuel consumption was found to be even lower than the conventional diesel for blends up to B20. The brake thermal efficiency for B10 and B20 were also closer to diesel and the CO2 emissions were found to be lesser than diesel while there was a marginal increase in the smoke opacity and NOX. The increase in opacity can be effectively managed by engine optimization. The reductions in brake specific fuel consumption and CO2 emissions made the blend of biodiesel B20 a suitable alternative fuel for diesel and thus could help in controlling air pollution.

V. Arumugham

Papers

Performance and emission characteristics of CI engine fuelled with non edible vegetable oil and diesel blends.

Significance of Metrological Tools in an ISO 17025 Accredited Quality System for a Biological Evaluation Facility