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A P Roskilly - One of the best experts on this subject based on the ideXlab platform.
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performance simulation of a spark ignited free piston Engine generator
Applied Thermal Engineering, 2008Co-Authors: R. Mikalsen, A P RoskillyAbstract:Free-piston Engines are under investigation by a number of research groups worldwide due to potential fuel efficiency and Engine emissions advantages. The free-piston Engine generator, in which a linear electric generator is fixed to the mover to produce electric power, has been proposed as an alternative prime mover for hybrid-electric vehicles. This paper investigates the performance of a spark ignited free-piston Engine generator and compares it to a Conventional Engine using a computational fluid dynamics simulation model. The particular operating characteristics of the free-piston Engine were not found to give noticeable performance advantages, and it is concluded that the main potential of this technology lies in the simplicity and flexibility of the concept.
R. Mikalsen - One of the best experts on this subject based on the ideXlab platform.
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The fuel efficiency and exhaust gas emissions of a low heat rejection free-piston diesel Engine
Proceedings of the Institution of Mechanical Engineers Part A: Journal of Power and Energy, 2009Co-Authors: R. Mikalsen, Anthony Paul RoskillyAbstract:AbstractThis article investigates the in-cylinder heat transfer losses of a free-piston diesel Engine and compares the results with those of a Conventional Engine, using a multidimensional simulati...
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A computational study of free-piston diesel Engine combustion
Applied Energy, 2008Co-Authors: R. Mikalsen, Anthony Paul RoskillyAbstract:This paper investigates the in-cylinder gas motion, combustion process and nitrogen oxide formation in a free-piston diesel Engine and compares the results to those of a Conventional Engine, using a computational fluid dynamics Engine model. Enhanced radial gas flow (squish and reverse squish) around top dead centre is found for the free-piston Engine compared to a Conventional Engine, however it is found that this has only minor influence on the combustion process. A higher heat release rate from the pre-mixed combustion phase due to an increased ignition delay was found, along with potential reductions in nitrogen oxides emissions formation for the free-piston Engine.
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performance simulation of a spark ignited free piston Engine generator
Applied Thermal Engineering, 2008Co-Authors: R. Mikalsen, A P RoskillyAbstract:Free-piston Engines are under investigation by a number of research groups worldwide due to potential fuel efficiency and Engine emissions advantages. The free-piston Engine generator, in which a linear electric generator is fixed to the mover to produce electric power, has been proposed as an alternative prime mover for hybrid-electric vehicles. This paper investigates the performance of a spark ignited free-piston Engine generator and compares it to a Conventional Engine using a computational fluid dynamics simulation model. The particular operating characteristics of the free-piston Engine were not found to give noticeable performance advantages, and it is concluded that the main potential of this technology lies in the simplicity and flexibility of the concept.
Yousef M Abdel-rahim - One of the best experts on this subject based on the ideXlab platform.
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Rapid thermodynamic simulation model for optimum performance of a four-stroke, direct-injection, and variable-compression-ratio diesel Engine
International Journal of Energy and Environmental Engineering, 2012Co-Authors: Maher M Abou Al-sood, Mahmoud Ahmed, Yousef M Abdel-rahimAbstract:A thermodynamic simulation model for the performance of a four-stroke, direct-injection diesel Engine is developed. The simulation model includes detailed sub-models for fuel burning rate, combustion products, thermodynamic properties of working fluid, heat transfer, fluid flow, and both soot and oxides of nitrogen (NO_x) formation mechanisms. To validate the model, comparisons between experimental and predicted results for different Engines, operating under different conditions, were conducted. The comparisons show that there is a good concurrence between measured and predicted values. An optimization analysis is conducted for seeking an optimum variation of compression ratio to achieve pre-set objective targets such as constant minimum brake-specific fuel consumption and constant maximum torque. The optimization analysis is performed under the constraint that the maximum pressure and temperature inside the cylinder do not exceed the maximum allowable pressure and temperature of the Conventional Engine (constant compression ratio).The varying compression ratio is optimized with each of the previous conditions separately. Results indicated that varying the compression ratio to achieve previous targets leads to saving fuel consumption, higher brake efficiency and power, and reduction in soot emission from the Engine. Also, an increase in NO_x is noticed at low speed. This drawback is considerable and can be overcome by reducing the operation speed range.
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Optimum Compression Ratio Variation of 4-Stroke, Direct Injection Diesel Engine for Optimum Performance
Volume 4: Energy Systems Analysis Thermodynamics and Sustainability; Combustion Science and Engineering; Nanoengineering for Energy Parts A and B, 2011Co-Authors: M.m. Abou Al-sood, Mahmoud Ahmed, Yousef M Abdel-rahimAbstract:A thermodynamic model for simulation the performance of a four-stroke direct-injection (DI) diesel Engine is developed. The simulation model includes detailed sub-models for fuel burning rate, combustion products, thermodynamic properties of working fluid, heat transfer, fluid flow, and both soot and NOx formation mechanisms. To validate the model, comparisons between experimental and predicted results for different Engines, operating under different conditions were conducted. Comparisons show that there is a good concurrence between measured and predicted values. An optimization analysis is conducted for seeking an optimum variation of compression ratio to achieve pre-set objective target of constant minimum brake specific fuel consumption (bsfc). The optimization analysis is performed under the constrain that the maximum pressure and temperature inside the cylinder not exceed the maximum allowable pressure and temperature of the Conventional Engine (constant rc ). Varying compression ratio is optimized with the previous condition. Results indicated that, at the values of rc ranged between 16.4 and 17.8, the optimum bsfc is attained with an increase in brake power by about 3.8%, while the bsfc and soot emission are reduced by about 4.4% and 21%, respectively. In addition to an increase in NOx , maximum pressure (pmax ), and maximum temperature (Tmax ) by about 75%, 6% and 4.3%, respectively.Copyright © 2011 by ASME
Psn Murthy - One of the best experts on this subject based on the ideXlab platform.
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comparative studies on performance evaluation of di diesel Engine with high grade low heat rejection combustion chamber with carbureted alcohols and crude jatropha oil
Renewable & Sustainable Energy Reviews, 2014Co-Authors: M Murali V S Krishna, Kishen Kumar T Reddy, Psn MurthyAbstract:Search for renewable fuels such as vegetable oils and alcohols (ethanol and methanol) has become pertinent in the context of fossil fuel crisis and vehicle population explosion. The drawbacks associated with vegetable oils (high viscosity and low volatility) and alcohols (low cetane number) for use in diesel Engines call for a hot combustion chamber, with its significant characteristics of higher operating temperature, maximum heat release, higher brake thermal efficiency and ability to handle the lower calorific value fuel. Investigations were carried out to evaluate the performance of a direct injection compression ignition Engine with high grade low heat rejection (LHR) combustion chamber consisting of air gap insulated piston with 3mm air gap with superni (an alloy of nickel) crown, air gap insulated liner with superni insert and ceramic coated cylinder head fueled with crude jatropha oil and carbureted alcohol (ethanol/methanol) with varied injection timings and injector opening pressures. Carbureted alcohol was inducted into the Engine through a variable jet carburetor, installed at the inlet manifold of the Engine at different percentages of crude vegetable oil at full load operation on mass basis. Comparative studies were made with Engine with LHR combustion chamber with data of Conventional Engine with test fuels of diesel, crude vegetable oil and carbureted alcohol at recommended injection timing and optimized injection timing. Comparative studies were also made with methanol operation with data of ethanol operation on both versions of the combustion chamber with different operating conditions. Performance parameters, exhaust emissions and combustion characteristics were determined at full load operation of the Engine with varied injection timings and injector opening pressures. Aldehydes were measured by the dinitrophenyl hydrazine (DNPH) method. Combustion diagnosis was carried out with a miniature piezoelectric pressure transducer, top dead center (TDC) encoder and special pressure–crank angle software package. The optimum injection timing was observed to be 32° bTDC with Conventional Engine while it was 29° bTDC for insulated Engine with vegetable oil operation. The maximum induction of alcohol (methanol/ethanol) in Conventional Engine was found to be 35%, while it was 60% for the Engine with LHR combustion chamber at recommended injection timing (27° bTDC). However, the maximum induction of alcohol was observed to be 55% with Engine with LHR combustion chamber at its optimum injection timing. With maximum induction of methanol, at an injector opening pressure of 190bar, Engine with LHR combustion chamber at its optimum injection timing increased peak brake thermal efficiency by 3%; at full load operation brake specific energy consumption comparable, decreased exhaust gas temperature by 3%, decreased coolant load by 6%, volumetric efficiency comparable, increased formaldehyde levels by 30%, decreased acetaldehyde levels by 35%, decreased particulate emissions by 20%, decreased nitrogen oxide levels by 14%, increased peak pressures by 3% and maximum rate of pressure rose by 3%, when compared with ethanol operation on Engine with LHR combustion chamber at its optimum injection timing.
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performance evaluation of a low grade low heat rejection dieselEngine with crude pongamia oil
International Scholarly Research Notices, 2012Co-Authors: Ch Kesava Reddy, M Murali V S Krishna, Psn Murthy, Ratna T ReddyAbstract:Investigations are carried out to evaluate the performance of a low heat rejection (LHR) diesel Engine with ceramic coated cylinder head [ceramic coating of thickness 500 microns is done on inside portion of cylinder head] with different operating conditions [normal temperature and pre-heated temperature] of crude Pongamia oil (CPO) with varied injection pressure and injection timing. Performance parameters and pollution levels are determined at various magnitudes of brake mean effective pressure. Combustion characteristics at peak load operation of the Engine are measured with special pressure-crank angle software package. Conventional Engine (CE) showed deteriorated performance, while LHR Engine showed improved performance with CPO operation at recommended injection timing and pressure and the performance of both version of the Engine is improved with advanced injection timing and at higher injection pressure when compared with CE with pure diesel operation. The optimum injection timing is 31°bTDC for Conventional Engine while it is 29°bTDC with LHR Engine with vegetable oil operation. Peak brake thermal efficiency increased by 5%, smoke levels decreased by 2% and NOx levels increased by 40% with CPO operation on LHR Engine at its optimum injection timing, when compared with pure diesel operation on CE at manufacturer’s recommended injection timing.
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a comparative study of the performance of a low heat rejection Engine with three different levels of insulation with vegetable oil operation
Archive of Mechanical Engineering, 2012Co-Authors: M Murali V S Krishna, N. Janardhan, Psn Murthy, P Ushasri, N SaradaAbstract:Investigations are carried out to evaluate the performance of a low heat rejection (LHR) diesel Engine consisting of different versions such as ceramic coated cylinder head Engine-LHR-1; Air gap insulated piston and air gap insulated linerLHR-2; and Ceramic coated cylinder head, air gap insulated piston and air gap insulated liner –LHR-3 with normal temperature condition of linseed oil with varied injection pressure. Performance parameters are determined at various magnitudes of brake mean effective pressure. Pollution levels of smoke and oxides of nitrogen (NOx) are recorded at the peak load operation of the Engine. Combustion characteristics of the Engine are measured with TDC (top dead centre) encoder, pressure transducer, console and special pressure-crank angle software package. Conventional Engine (CE) showed deteriorated performance and LHR Engines showed improved performance at recommended injection timing of 27 o bTDC and recommend injection pressure of 190 bar with vegetable oil operation, when compared with CE with pure diesel operation. Peak brake thermal efficiency increased by 12.5%, compatible smoke levels and NOx levels increased by 49% with LHR-3 Engine at an injection pressure of 190 bar when compared with pure diesel operation on CE at an injection pressure of 190 bar.
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studies on exhaust emissions from copper coated gasohol run spark ignition Engine with catalytic converter
International Scholarly Research Notices, 2011Co-Authors: Narasimha S Kumar, M Murali V S Krishna, K. Kishor, Psn MurthyAbstract:The major pollutants emitted from spark ignition Engine are carbon monooxide (CO) and unburnt hydrocarbons (UHC). These are hazardous and cause health problems to human beings, and hence control of these pollutants calls for immediate attention. Copper of thickness 300 microns is coated over piston crown and inside portion of the cylinder head of the spark ignition Engine. Investigations have been carried out for reducing pollutants from a variable compression ratio, copper-coated spark ignition Engine fitted with catalytic converter containing sponge iron catalyst run with gasohol (blend of 20% ethanol and 80% gasoline by volume). The influence of parameters such as void ratio, airflow rate, temperature of injected air, speed, compression ratio, and load of the Engine on these emissions are studied. A microprocessor-based analyzer is used for the measurement of CO/UHC in the exhaust of the Engine. The speed, load, compression ratio and the injection of air into the catalytic converter are found to show strong influence on reduction of the pollutants in the exhaust. Copper-coated spark ignition Engine with gasohol operation reduced the exhaust emissions considerably when compared to Conventional Engine with pure gasoline operation.
M Murali V S Krishna - One of the best experts on this subject based on the ideXlab platform.
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comparative studies on performance evaluation of di diesel Engine with high grade low heat rejection combustion chamber with carbureted alcohols and crude jatropha oil
Renewable & Sustainable Energy Reviews, 2014Co-Authors: M Murali V S Krishna, Kishen Kumar T Reddy, Psn MurthyAbstract:Search for renewable fuels such as vegetable oils and alcohols (ethanol and methanol) has become pertinent in the context of fossil fuel crisis and vehicle population explosion. The drawbacks associated with vegetable oils (high viscosity and low volatility) and alcohols (low cetane number) for use in diesel Engines call for a hot combustion chamber, with its significant characteristics of higher operating temperature, maximum heat release, higher brake thermal efficiency and ability to handle the lower calorific value fuel. Investigations were carried out to evaluate the performance of a direct injection compression ignition Engine with high grade low heat rejection (LHR) combustion chamber consisting of air gap insulated piston with 3mm air gap with superni (an alloy of nickel) crown, air gap insulated liner with superni insert and ceramic coated cylinder head fueled with crude jatropha oil and carbureted alcohol (ethanol/methanol) with varied injection timings and injector opening pressures. Carbureted alcohol was inducted into the Engine through a variable jet carburetor, installed at the inlet manifold of the Engine at different percentages of crude vegetable oil at full load operation on mass basis. Comparative studies were made with Engine with LHR combustion chamber with data of Conventional Engine with test fuels of diesel, crude vegetable oil and carbureted alcohol at recommended injection timing and optimized injection timing. Comparative studies were also made with methanol operation with data of ethanol operation on both versions of the combustion chamber with different operating conditions. Performance parameters, exhaust emissions and combustion characteristics were determined at full load operation of the Engine with varied injection timings and injector opening pressures. Aldehydes were measured by the dinitrophenyl hydrazine (DNPH) method. Combustion diagnosis was carried out with a miniature piezoelectric pressure transducer, top dead center (TDC) encoder and special pressure–crank angle software package. The optimum injection timing was observed to be 32° bTDC with Conventional Engine while it was 29° bTDC for insulated Engine with vegetable oil operation. The maximum induction of alcohol (methanol/ethanol) in Conventional Engine was found to be 35%, while it was 60% for the Engine with LHR combustion chamber at recommended injection timing (27° bTDC). However, the maximum induction of alcohol was observed to be 55% with Engine with LHR combustion chamber at its optimum injection timing. With maximum induction of methanol, at an injector opening pressure of 190bar, Engine with LHR combustion chamber at its optimum injection timing increased peak brake thermal efficiency by 3%; at full load operation brake specific energy consumption comparable, decreased exhaust gas temperature by 3%, decreased coolant load by 6%, volumetric efficiency comparable, increased formaldehyde levels by 30%, decreased acetaldehyde levels by 35%, decreased particulate emissions by 20%, decreased nitrogen oxide levels by 14%, increased peak pressures by 3% and maximum rate of pressure rose by 3%, when compared with ethanol operation on Engine with LHR combustion chamber at its optimum injection timing.
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comparative studies on medium grade low heat rejection diesel Engine and Conventional diesel Engine with crude cotton seed oil
International Journal of Innovative Research in Science Engineering and Technology, 2013Co-Authors: D Srikanth, M Murali V S Krishna, Jaya Prakash NarayanAbstract:It has been found that the vegetable oils are promising substitute, because of their properties are similar to those of diesel fuel and they are renewable and can be easily produced. However, drawbacks associated with crude vegetable oils are high viscosity, low volatility call for low heat rejection diesel Engine. Comparative studies were made on performance evaluation of medium grade LHR diesel Engine (with air gap insulated piston with superni ( an alloy of nickel) crown and air gap insulated liner with superni insert) and Conventional diesel Engine (CE) with different operating conditions (normal temperature and pre-heated temperature) of crude cotton seed oil with varied injector opening pressure and injection timing. Performance parameters (brake thermal efficiency, brake exhaust gas temperature, volumetric efficiency, sound levels and coolant load), exhaust emissions (smoke levels and oxides of nitrogen) were determined at various values of brake mean effective pressure of the Engine. Combustion characteristics (peak pressure, maximum rate of pressure rise and time of occurrence of peak pressure) were evaluated at peak load operation of the Engine. Conventional Engine showed deteriorated performance, while LHR Engine showed improved performance with cotton seed oil at recommended injection timing and pressure in comparison with pure diesel operation on CE. The optimum injection timing was 32 o bTDC with Conventional Engine, while it was 30 o bTDC for LHR Engine with cotton seed oil operation.
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performance evaluation of a low grade low heat rejection dieselEngine with crude pongamia oil
International Scholarly Research Notices, 2012Co-Authors: Ch Kesava Reddy, M Murali V S Krishna, Psn Murthy, Ratna T ReddyAbstract:Investigations are carried out to evaluate the performance of a low heat rejection (LHR) diesel Engine with ceramic coated cylinder head [ceramic coating of thickness 500 microns is done on inside portion of cylinder head] with different operating conditions [normal temperature and pre-heated temperature] of crude Pongamia oil (CPO) with varied injection pressure and injection timing. Performance parameters and pollution levels are determined at various magnitudes of brake mean effective pressure. Combustion characteristics at peak load operation of the Engine are measured with special pressure-crank angle software package. Conventional Engine (CE) showed deteriorated performance, while LHR Engine showed improved performance with CPO operation at recommended injection timing and pressure and the performance of both version of the Engine is improved with advanced injection timing and at higher injection pressure when compared with CE with pure diesel operation. The optimum injection timing is 31°bTDC for Conventional Engine while it is 29°bTDC with LHR Engine with vegetable oil operation. Peak brake thermal efficiency increased by 5%, smoke levels decreased by 2% and NOx levels increased by 40% with CPO operation on LHR Engine at its optimum injection timing, when compared with pure diesel operation on CE at manufacturer’s recommended injection timing.
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a comparative study of the performance of a low heat rejection Engine with three different levels of insulation with vegetable oil operation
Archive of Mechanical Engineering, 2012Co-Authors: M Murali V S Krishna, N. Janardhan, Psn Murthy, P Ushasri, N SaradaAbstract:Investigations are carried out to evaluate the performance of a low heat rejection (LHR) diesel Engine consisting of different versions such as ceramic coated cylinder head Engine-LHR-1; Air gap insulated piston and air gap insulated linerLHR-2; and Ceramic coated cylinder head, air gap insulated piston and air gap insulated liner –LHR-3 with normal temperature condition of linseed oil with varied injection pressure. Performance parameters are determined at various magnitudes of brake mean effective pressure. Pollution levels of smoke and oxides of nitrogen (NOx) are recorded at the peak load operation of the Engine. Combustion characteristics of the Engine are measured with TDC (top dead centre) encoder, pressure transducer, console and special pressure-crank angle software package. Conventional Engine (CE) showed deteriorated performance and LHR Engines showed improved performance at recommended injection timing of 27 o bTDC and recommend injection pressure of 190 bar with vegetable oil operation, when compared with CE with pure diesel operation. Peak brake thermal efficiency increased by 12.5%, compatible smoke levels and NOx levels increased by 49% with LHR-3 Engine at an injection pressure of 190 bar when compared with pure diesel operation on CE at an injection pressure of 190 bar.
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studies on exhaust emissions from copper coated gasohol run spark ignition Engine with catalytic converter
International Scholarly Research Notices, 2011Co-Authors: Narasimha S Kumar, M Murali V S Krishna, K. Kishor, Psn MurthyAbstract:The major pollutants emitted from spark ignition Engine are carbon monooxide (CO) and unburnt hydrocarbons (UHC). These are hazardous and cause health problems to human beings, and hence control of these pollutants calls for immediate attention. Copper of thickness 300 microns is coated over piston crown and inside portion of the cylinder head of the spark ignition Engine. Investigations have been carried out for reducing pollutants from a variable compression ratio, copper-coated spark ignition Engine fitted with catalytic converter containing sponge iron catalyst run with gasohol (blend of 20% ethanol and 80% gasoline by volume). The influence of parameters such as void ratio, airflow rate, temperature of injected air, speed, compression ratio, and load of the Engine on these emissions are studied. A microprocessor-based analyzer is used for the measurement of CO/UHC in the exhaust of the Engine. The speed, load, compression ratio and the injection of air into the catalytic converter are found to show strong influence on reduction of the pollutants in the exhaust. Copper-coated spark ignition Engine with gasohol operation reduced the exhaust emissions considerably when compared to Conventional Engine with pure gasoline operation.