Experimental Investigations on DI Diesel Engine With Low Heat Rejection Combustion Chamber With Carbureted Ethanol and Crude Jatropha Oil

Author(s):  
Vencherla V. R. Seshagiri Rao ◽  
Maddali V. S. Murali Krishna ◽  
T. Kishen Kumar Reddy ◽  
D. Srikanth ◽  
P. V. Krishna Murthy

It has been found that the vegetable oils and alcohols (ethanol and methanol) are promising substitute fuels for diesel fuel, because they are renewable in nature. However drawbacks associated with crude vegetable oil (high viscosity and low volatility) and ethanol (low cetane number and low energy content) which cause combustion problems in CI engines, call for engine with hot combustion chamber. Investigations were carried out on single–cylinder, four–stroke, water cooled, 3.68 kW direct injection diesel engine at a speed of 1500 rpm to evaluate the performance of a engine with medium grade low heat rejection (LHR) combustion chamber. It consisted of an air gap insulated piston and an air gap insulated liner fuelled with crude jatropha oil and carbureted ethanol with varied injection timing and injector opening pressure. Carbureted ethanol was inducted into the engine through a variable jet carburetor. This carburetor was installed at the inlet manifold of the engine and ethanol was inducted at different percentages of crude vegetable oil at full load operation on mass basis. Aldehydes (measured by dinitrophenyl hydrazine method), particulate emissions and oxides of nitrogen were measured at full load operation of the engine. With maximum induction of ethanol, engine with LHR combustion chamber showed improved performance over conventional engine at 27°bTDC and optimized injection timing.

Author(s):  
Raavi Peraiah Chowdary ◽  
Maddali V. S. Murali Krishna ◽  
T. Kishen Kumar Reddy ◽  
D. Srikanth ◽  
P. V. Krishna Murthy ◽  
...  

Biodiesels derived from vegetable oils present a very promising alternative fuels for diesel fuel, since they have numerous advantages compared to fossil fuels. However crude vegetable oil and biodiesel have high viscosity and low volatility causing combustion problems in CI engines, call for engine with hot combustion chamber. Investigations were carried out on single–cylinder, four–stroke, water cooled, 3.68 kW direct injection diesel engine at a speed of 1500 rpm to evaluate the performance of a engine with low heat rejection (LHR) combustion chamber. It consisted of an air gap (3 mm) insulated piston with superni (an alloy of nickel) crown and an air gap (3 mm) insulated liner with superni insert and ceramic coated cylinder head fuelled with different operating conditions (normal temperature and preheated temperature) of waste fried vegetable oil and its biodiesel with varied injection timing and injector opening pressure. Engine with LHR combustion chamber with biodiesel showed improved performance over conventional engine (CE) at 27° bTDC and at optimum injection timing. Biodiesel showed improved performance over crude vegetable oil with engine with both versions of the combustion chamber. Preheated test fuels and increase of injection pressure showed reduction of pollution levels and marginally improved performance over normal test fuels.


Author(s):  
N. Janardhan ◽  
M.V.S. Murali Krishna ◽  
P. Ushasri ◽  
P.V.K. Murthy

Investigations were carried out to evaluate the performance of a low heat rejection (LHR) diesel engine consisting of air gap insulated piston with 3-mm air gap, with superni (an alloy of nickel) crown, air gap insulated liner with superni insert and ceramic coated cylinder head with different operating conditions of crude jatropha oil (CJO) with varied injection timing and injector opening pressure . Performance parameters [brake thermal efficiency, exhaust gas temperature, coolant load and volumetric efficienc and exhaust emissions [smoke and oxides of nitroge were determined at various values of brake mean effective pressure (BMEP). Combustion characteristics [ peak pressure, time of occurrence of peak pressure and maximum rate of pressure ris of the engine were at peak load operation of the engine. Conventional engine (CE) showed deteriorated performance, while LHR engine showed improved performance with vegetable operation at recommended injection timing and pressure. The performance of both versions of the engine improved with advanced injection timing and higher injector opening pressure when compared with CE with pure diesel operation. Relatively, peak brake thermal efficiency increased by 14%, smoke levels decreased by 27% and NOx levels increased by 49% with vegetable oil operation on LHR engine at its optimum injection timing, when compared with pure diesel operation on CE at manufacturers recommended injection timing.


2015 ◽  
Vol 813-814 ◽  
pp. 830-835
Author(s):  
Akkaraju H. Kiran Theja ◽  
Rayapati Subbarao

The drawbacks associated with bio-fuels can be minimized by making modifications to combustion chamber. Modification of combustion chamber is achieved by providing an air gap in between the crown and the body of the piston with the top crown made of low thermal conductivity material. Experimentation is carried on a diesel engine with brass as piston crown material and karanja as test fuel, which is found to be a better alternative fuel based on the tests carried out prior to modification. Investigations are carried out on the performance of the engine with modified combustion chamber consisting of air gap insulated piston with 2 mm air gap with brass crown when fuelled with karanja oil. Comparative studies are made between the two configurations of engine with and without modification at an injection timing of 29obTDC. Performance, heat balance and emission plots are made with respect to brake power. Fuel consumption increased with modification. The mechanical and volumetric efficiencies are similar in both the cases. Indicated and brake thermal efficiencies got reduced with modification. But, it is good to see that HC and CO emissions are showing positive trend. Thus, the present investigation hints the possibility of improvements while making piston modification and providing air gap insulation.


Author(s):  
M. V. S. Murali Krishna ◽  
C. M. Vara Prasad ◽  
Tandur Rajashekar ◽  
Supriya Tiwari ◽  
T. Sujani

Jatropha oil, a non-edible vegetable oil shows a greater potential for replacing conventional diesel fuel quite effectively, as its properties are compatible to that of diesel fuel. But low volatility and high viscosity of jatropha oil call for hot combustion chamber, which is provided by a low heat rejection diesel engine with threaded air gap piston and liner with superni-90 inserts. The performance of the engine with jatropha oil is obtained with different versions of the engine such as conventional engine and insulated engine at normal and preheat condition of the oil, with varying injection pressure and timing and compared to the engine with pure diesel operation at recommended injection pressure and timing. Increase of thermal efficiency of 18% and reduction of NOx levels by 5% are observed at optimized injection timing and at higher injection pressure with insulated engine at preheat condition of jatropha oil in comparison with pure diesel operation on conventional engine.


2014 ◽  
Vol 18 (1) ◽  
pp. 53-65 ◽  
Author(s):  
S. Jafarmadar

Higher heat losses and brake specific fuel consumption (BSFC) are major problems in an indirect injection (IDI) diesel engine, which can be overcome by means of low heat rejection (LHR) concept. This concept is based on the approach of insulating of piston and liner of main chamber in IDI engine. At the present work, the combustion process and emission formation in baseline and LHR engines are studied by a Computational Fluid Dynamics (CFD) code at four different loads (25%, 50%, 75% and 100%) in maximum torque engine speed 730rpm. The numerical results for the pressure in cylinder and emissions for baseline engine at full load operation are compared to the corresponding experimental data and show good agreement. The comparison of the results for two cases show that when the load increases from 25% to 100% in 25% steps, heat loss in LHR engine decrease 40.3%, 44.7%,44.6% and 45.2%, respectively. At full load operation in LHR engine, NOx and Soot emissions decrease 13.5% and 54.4%, respectively and engine efficiency increases 6.3% in comparison to baseline engine.


Author(s):  
P. Prakash ◽  
C. Dhanasekaran

This paper describes about the usage of Jatropha fuel in direct injection water-cooled diesel engine. In order to make use of Jatropha fuel in diesel engine, the properties of Jatropha oil has to be converted to diesel fuel, so for that methanol was added. There are three different blends are prepared by varying the ratio of Jatropha and methanol mixture, such as blend 1 (Jatropha 75%, methanol 25%), blend 2 (Jatropha 80%, methanol 20%), blend 3 (Jatropha 85%, methanol 15%). The prepared fuels are supplied to the conventional diesel engine, then the performance and emission characteristics were analysed. It is found that Jatropha methanol mixtures results are acceptable in half load and highly considerable in full load operation. Considerably torque developed is very low in low load than half and full load operations. Methanol addition has improved the performance and emission characteristics.


1999 ◽  
Vol 121 (3) ◽  
pp. 530-539 ◽  
Author(s):  
K. Rama Mohan ◽  
C. M. Vara Parasad ◽  
M. V. S. Murali Krishna

A threaded air gap insulated piston provided effective insulation without causing sealing problems. The performance of the diesel engine with the air gap insulated piston was obtained with different piston crown materials, at differing magnitudes of air gap with varying injection timings. The engine using Nimonic for the piston crown with an air gap of 3 mm at an injection timing of 29.5° bTDC reduced the BSFC by 12 percent at part loads and 4 percent at full load. The performance in terms of P-θ and T-θ was predicted employing a zero dimensional multizone combustion model, and the model results have been validated with measured pressures and the exhaust gas temperatures. More appropriate piston surface temperatures were employed in Annand’s equation to improve the computer predictions using finite element modeling of the piston. The measured temperatures of air in the air gap using an L-link mechanism provided excellent validation for the finite element prediction of isotherms in the piston.


2014 ◽  
Vol 61 (4) ◽  
pp. 627-651 ◽  
Author(s):  
M.V.S. Murali Krishna ◽  
N. Durga Prasada Rao ◽  
B. Anjeneya Prasad ◽  
P.V.K. Murthy

Abstract 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 combustion chamber, with its significance characteristics of higher operating temperature, maximum heat release, and ability to handle lower calorific value (CV) fuel etc. Experiments were carried out to evaluate the performance of an engine consisting of different low heat rejection (LHR) combustion chambers such as ceramic coated cylinder head-LHR-1, air gap insulated piston with superni (an alloy of nickel) crown and air gap insulated liner with superni insert - LHR-2; and ceramic coated cylinder head, air gap insulated piston and air gap insulated liner - LHR-3 with normal temperature condition of crude rice bran oil (CRBO) with varied injector opening pressure. Performance parameters (brake thermal efficiency, brake specific energy consumption, exhaust gas temperature, coolant load, and volumetric efficiency) and exhaust emissions [smoke levels and oxides of nitrogen [NOx]] were determined at various values of brake mean effective pressure of the engine. Combustion characteristics [peak pressure, time of occurrence of peak pressure, maximum rate of pressure rise] were determined at full load operation of the engine. Conventional engine (CE) showed compatible performance and LHR combustion chambers showed improved performance at recommended injection timing of 27°bTDC and recommend injector opening pressure of 190 bar with CRBO operation, when compared with CE with pure diesel operation. Peak brake thermal efficiencyincreased relatively by 7%, brake specific energy consumption at full load operation decreased relatively by 3.5%, smoke levels at full load decreased relatively by 11% and NOx levels increased relatively by 58% with LHR-3 combustion chamber with CRBO at an injector opening pressure of 190 bar when compared with pure diesel operation on CE


2011 ◽  
Vol 110-116 ◽  
pp. 1368-1373 ◽  
Author(s):  
Amar P. Pandhare ◽  
S. G. Wagholikar ◽  
R. B. Jadhav Sachin Musale ◽  
A. S. Padalkar

The heterogeneous catalyst are environment friendly and render the process simplified. A wide variety of solid bases have been examined for this process. The present work reports the use of hydrotalcite catalyst for the synthesis of Biodiesel from jatropha oil. An experimental investigation has been carried out to analyze the performance and emission characteristics of a compression ignition engine fuelled with Jatropha oil and its blends (10%, 20%, 40%, 50%, and 60 % ) with mineral diesel. The effect of temperature on the viscosity of Jatropha oil has also been investigated. A series of engine tests, have been conducted using each of the above fuel blends for comparative performance evaluation. The performance parameters evaluated include thermal efficiency, brake specific fuel consumption (BSFC), brake specific energy consumption (BSEC), and exhaust gas temperature whereas exhaust emissions include mass emissions of CO, HC, NO. These parameters were evaluated in a single cylinder compression ignition diesel engine. The results of the experiment in each case were compared with baseline data of mineral diesel. Significant improvements have been observed in the performance parameters of the engine as well as exhaust emissions. The gaseous emissions of oxide of nitrogen from all blends are lower than mineral diesel at all engine loads. Jatropha oil blends with diesel (up to 50% v/v) can replace diesel for operating the CI engines giving lower emissions and improved engine performance. More over results indicated that B20 have closer performance to diesel and B100 have lower brake thermal efficiency mainly due to its high viscosity compared to diesel.


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