Environmental degradation and depleting oil reserves are matters of great concern round the globe. Developing countries like India depend heavily on oil import. Diesel being the main transport fuel in India, finding a suitable alternative to diesel is an urgent need. Jatropha based bio-diesel (JBD) is a non-edible, renewable fuel suitable for diesel engines and is receiving increasing attention in India because of its potential to generate large-scale employment and relatively low environmental degradation. Diesel engines running on JBD are found to emit higher oxides of nitrogen, NOx. HOT EGR, a low cost technique of exhaust gas recirculation, is effectively used in this work to overcome this environmental penalty. Practical problems faced while using a COOLED EGR system are avoided with HOT EGR. Results indicated higher nitric oxide (NO) emissions when a single cylinder diesel engine was fuelled with JBD, without EGR. NO emissions were reduced when the engine was operated under HOT EGR levels of 5-25%. However, EGR level was optimized as 15% based on adequate reduction in NO emissions, minimum possible smoke, CO, HC emissions and reasonable brake thermal efficiency. Smoke emissions of JBD in the higher load region were lower than diesel, irrespective of the EGR levels. However, smoke emission was higher in the lower load region. CO and HC emissions were found to be lower for JBD irrespective of EGR levels. Combustion parameters were found to be comparable for both fuels. © 2006 Elsevier Ltd. All rights reserved.

V. Pradeep

Environmental impact

Ignition

Nitrogen oxides

Particulate emissions

Brake thermal efficiency

HOT EGR SYSTEMS

NITRIC OXIDE (NO)

Pollution control

Compression

developing world

Diesel

diesel engine

Environmental degradation

Nitric oxide

NITROUS OXIDE

OLD FIELD

Renewable resource

Vegetable oil

Asia

Eurasia

India

South Asia

Jatropha

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Renewable Energy

Biodiesel fuels comprised of mono-alkyl esters of long chain fatty acids derived from vegetable oils or animal fats serve as a potential alternative to fossil diesel. The biodiesel fueled engine does not require any major hardware modifications in the existing configuration. Also, the uses of biodiesel in compression ignition engines are found to significantly lower soot emissions. Thus, the conventional nitric oxide-soot trade-off problem narrows down to a unidirectional control of nitric oxide emissions which are generally known to increase with several candidate biodiesel fuels. The formation of oxides of nitrogen (NOx) from biodiesel fuel is dependent on both fuel and engine characteristics. The present work reviews the effect of biodiesel fuel composition and properties on NOx emissions emanating from biodiesel fueled engines and describes fuel modifications and engine tuning measures for their mitigation. The other outcomes of biodiesel NOx control measures in terms of engine performance and emission changes are also highlighted and the best possible ways for achieving biodiesel-NOx neutrality are outlined. © 2016 Elsevier Ltd. All rights reserved.

Renewable and Sustainable Energy Reviews

Biodiesel NOx penalty and control measures - A review

500 h durability, performance and emission tests are conducted on a single cylinder high speed automotive diesel engine for the ethanol blended biodiesel fuel. Esterified cotton seed methyl ester of 5% by volume is mixed with 95% neat diesel to obtain the base biodiesel fuel (B5). The base fuel is mixed with 20% pure ethanol to derive the ethanol blended biodiesel fuel (B5E20). The parameters like blow-by, crank case pressure and lubricating oil consumption are experimentally investigated along with performance and emission characteristics for both the test fuelled engines. The result of these tests showed a significant loss in maximum brake power and maximum brake torque at the end of 500 h durability run when the engine is fuelled with B5E20. The lubricating oil consumption and positive crank pressure of B5E20 fuelled engine is comparatively higher than B5 fuelled engine during the durability trials. Reduction in smoke and CO emissions are noticed for B5E20 fuel over the entire range of speed whereas NOX and unburned hydro carbon emissions get decreased at lower to medium speed range and increases thereafter. As expected, all the engine emissions increase after 500 h of durability run for both the fuels. © 2019

Experimental investigations of ethanol blended biodiesel fuel on automotive diesel engine performance, emission and durability characteristics

The present research work deals with the application of 30% exhaust gas recirculation (EGR) in a direct injection compression ignition engine fuelled with 100% waste cooking oil methyl ester and conventional diesel. In the first phase of this research work, the performance, emission and combustion characteristics of diesel engine are investigated with the supply of fresh air–fuel mixture for conventional diesel and waste cooking oil methyl ester as fuels and in the second phase the fresh air–fuel mixture is blended with 30% exhaust gas. The study reveals that the 30% EGR addition decreased the brake thermal efficiency by 8 and 18% for conventional diesel and 100% waste cooking oil methyl ester as fuels. Nitrogen oxides emission is reduced to a great extent by 47.5% for diesel fuel and 58.9% for biodiesel fuel at full load condition. Further, the 30% EGR has substantially increased the carbon monoxide and unburnt hydrocarbon emissions for both the fuels at maximum brake mean effective pressure. In addition similar pattern of in-cylinder gas pressure, heat release rate, cumulative heat rate have been observed for fresh air fuel mixture and 30% EGR under various loading conditions. © 2018, Springer Science+Business Media B.V., part of Springer Nature.

Waste and Biomass Valorization

Influence of Exhaust Gas Recirculation on Combustion and Emission Characteristics of Diesel Engine Fuelled with 100% Waste Cooking Oil Methyl Ester

Stringent emission regulations and depletion of crude oil are driving researchers toward alternative fuels. In this context, palm oil emerges as a good competitor as it is highly economical compared to other alternative fuels. The current research work centers around the impact of palm oil methyl ester on performance, combustion, and emission characteristics at varying injection timings and exhaust gas recirculation rates. In the first phase of this research work, various blends of palm oil methyl ester with diesel with volume concentrations of 10, 20, and 30% were prepared and tested at different load conditions. Injection timing was then varied for the optimized blend. In the second phase, the impact of exhaust gas blending with fresh charge was studied at optimized injection timing. The test outcomes revealed that 20% mix of palm oil at 27° bTDC with exhaust gas blending of 20% generated higher brake thermal efficiency, higher peak pressure, and less hydrocarbon and nitrogen oxide emissions compared to diesel at standard injection timing of 23° bTDC and no blending of exhaust gases with fresh charge. However, progression of injection timing with 20% exhaust gas mixing indicated a slight penalty in smoke discharges. Brake thermal efficiency at advanced injection timing with 20% mix of exhaust gases reduced by 7.7% for diesel and increased by 6.5% for 20% blend of palm oil when compared to standard injection timing of diesel and no blending of exhaust gases. Significant diminishments in oxides of nitrogen (lessened by 6.6%) and hydrocarbons (decreased by 30.43%) have been noted for 20% mix of biodiesel at advanced injection timing with 20% exhaust gas mix contrasted to diesel at standard conditions. Therefore, the present examination prescribes 20% merging of exhaust gases for 20% blend of palm oil with advancement of injection timing for diesel engine applications. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.

Environmental Science and Pollution Research

Engine parameter optimization of palm oil biodiesel as alternate fuel in CI engine

The present work examines the prospect of using 100% Calophyllum inophyllum methyl ester as a promising alternative fuel for future generation. In this research work, a strategy is developed to reduce NOX emissions of Calophyllum inophyllum biodiesel fuelled diesel engine by varying the injection timing between 21°, 23° and 25° bTDC and by admitting exhaust gas recirculation at the rate of 10%, 20% and 30%. The experiments are conducted in a four stroke diesel engine using 100% Calophyllum inophyllum biodiesel and the engine characteristics are compared with neat diesel engine. Certain important parameters like brake specific energy consumption, brake thermal efficiency, heat release rate, in-cylinder pressure, exhaust emissions including NOX and smoke density are evaluated for various injection timing and EGR rates. Retardation of injection timing to 21° bTDC reduces the NOX emissions very marginally with significant loss in engine performance. It is found that 10% exhaust gas recirculation rate could reduce the NOX emissions more effectively which would meet the proposed Euro V standards. Thus it is observed that exhaust gas recirculation is an effective method to control emissions of 100% Calophyllum inophyllum biodiesel without much compromise in engine efficiency when compared to the influence of injection timing. © 2016 Elsevier B.V.

Fuel Processing Technology

Influence of injection timing and exhaust gas recirculation of a Calophyllum inophyllum methyl ester fuelled CI engine

Use of vegetable oils in diesel engines results in increased smoke and reduced brake thermal efficiency. Dual fuel engines can use a wide range of fuels and yet operate with low smoke emissions and high thermal efficiency. In this work, a single cylinder diesel engine was converted to use vegetable oil (Jatropha oil) as the pilot fuel and methanol as the inducted primary fuel. Tests were conducted at 1500 rev/min and full load. Different quantities of methanol and Jatropha oil were used. Results of experiments with diesel as the pilot fuel and methanol as the primary fuel were used for comparison. Brake thermal efficiency increased in the dual fuel mode when both Jatropha oil and diesel were used as pilot fuels. The maximum brake thermal efficiency was 30.6% with Jatropha oil and 32.8% with diesel. Smoke was drastically reduced from 4.4 BSU with pure Jatropha oil operation to 1.6 BSU in the dual fuel mode. Hydrocarbon and carbon monoxide emissions were higher in the dual fuel mode with both fuels. Heat release pattern in the case of neat Jatropha oil operation showed a smaller premixed combustion phase and a larger diffusion combustion phase as compared to diesel operation. These phases were not distinguishable in the dual fuel mode. Copyright © 2001 Society of Automotive Engineers, Inc.

SAE Technical Papers

Experimental investigations on a jatropha oil methanol dual fuel engine

SAE Technical Paper Series

Potential Methods for NOx Reduction from Biodiesel

Fuel and Energy Abstracts

Effect of exhaust gas recirculation on some combustion characteristics of dual fuel engine

International Journal of Hydrogen Energy

Near-term introduction of hydrogen engines for automotive and agricultural application

Fuel Effects on Diesel Emissions - A New Understanding

Use of HOT EGR for NOx control in a compression ignition engine fuelled with bio-diesel from Jatropha oil

Journal	Renewable Energy
ISSN	09601481
Open Access	No