29-09-2012, 01:58 PM
PERFORMANCE IMPROVEMENT OF A DI DIESEL ENGINE USING COTTONSEED OIL
[attachment=34823]
ABSTRACT
Diesel engines are the prime movers for heavy-duty vehicles used in transportation and agricultural sectors. Diesel engines meet their energy requirement from stored fuels i.e. petroleum products. The twin problems of both depletion in scarce resources and atmospheric pollution caused by vehicles running on petro products are perturbing the researchers to find available and immediate alternative to fossil fuels.
The physical and combustion properties of vegetable oils are close to petro-diesel fuel and in this context, vegetable oils can stand as an immediate candidate substitute for stored fuels. Vegetable oils are produced from processing of seeds of various plants and thus Renewable in nature.
However due to inherent high viscosity and low volatility vegetable oils would pose problems such as fuel flow and poor atomization and constraining their direct use in engines without any modifications.
In the present investigation effect of supercharging is studied on the performance of a direct injection diesel engine with the use of untreated cottonseed oil.
Performance of the engine is evaluated in terms of break specific fuel consumption, exhaust Gas Temperature and smoke Density. It is observed that when cottonseed oil is used as a fuel, there is a reduction in BSFC of about 15% when the engine is run at the recommended injection pressure and supercharging pressure of 0.4 bar g in comparison with the engine operation run under naturally operated condition.
INTRODUCTION:
With the exponential growth of automotive vehicle population and increased stress on industrialization in developing countries, the impact of the twin problems of exhaust emission and the depletion of precious foreign exchange reserves for importing nonrenewable petroleum crude and products to keep the vehicles moving will indeed be very severe. The atmospheric pollution in major cities due to automobiles has already reached alarming levels.
Oil technologists predict that over the next several decades plant based oils will become just as essential for the transportation industry as fossil fuels like gasoline and diesel oil are today.
Vegetable oils are mixtures of fatty acids-molecules that contain carbon, hydrogen, and oxygen atoms. The fatty acids present in it may be saturated, mono-unsaturated, or poly-unsaturated. The greater the number of the double bonds, the more easily the compound reacts with oxygen from the air and goes bad, as kitchen fats and oils do after months on the shelfs.
Intensive search is being carried out in developing diesel engine fuels and lubricants based on vegetable oils. Due to high viscosity of vegetable oils, they interfere with fuel jet penetration, atomization and results in higher fuel consumption and leaves gummy deposits on the engine components upon combustion.
Barsic et al. [1] studied the performance and emission characteristics of a DI naturally aspirated diesel engine when operated on 100%sun flower oil, 100%peanut oil and 50% (by vol.) mixtures of either sun flower oil or peanut oil with #2 diesel oil (i.e. diesel fuel with less than 0.01%sulphur by weight) and compared results with base line results obtained using #2 diesel fuel. They adopted a rotary fuel injection pump and with fuel flow adjusted to provide equal fuel energy input and observed that the engine power and thermal efficiency decreased slightly and emissions increased marginally. The attributed reasons were higher densities, higher viscosities, relatively lower heating values and thermal cracking of vegetable oil fuel droplets at elevated temperatures.
RESULTS AND DISCUSSION:
The test results obtained in the above experiments are discussed below.
The recommended fuel injection pressure of the engine under consideration is 180 bar.
Effect of supercharging can be observed in fig. 1, for different supercharging pressures at the recommended fuel injection pressure. It is evident from the fig. That as the supercharging pressure is increased the BSFC is gradually lowered and the lowest values of BSFC are observed for supercharging pressure of 0.4 bar g. variation of exhaust Gas temperature with BMEP is plotted in fig. 2 at an injection pressure of 180 bar for different supercharging pressure. The exhaust temperature are lower at a supercharging pressure of 0.4 bar g indicating lower exhaust gas losses supporting the lower BSFC values observed in fig. 1 with this supercharging pressure.
CONCLUSIONS:
1. With increase in supercharging pressure the performance of the engine is gradually improving while maintaining the recommended injection pressure with cottonseed oil as fuel. There is a reduction of about 15% in BSFC at full load with a supercharging pressure of 0.4 bar g compared to naturally operated condition.
2. Supercharging is essential when we want to adopt untreated vegetable oils for developing the power with a low specific fuel consumption compared to diesel operation.
Percentage reduction in smoke density is more as the supercharging pressure is increased and engine performance with untreated vegetable oils can be regarded as eco-friendly operation
[attachment=34823]
ABSTRACT
Diesel engines are the prime movers for heavy-duty vehicles used in transportation and agricultural sectors. Diesel engines meet their energy requirement from stored fuels i.e. petroleum products. The twin problems of both depletion in scarce resources and atmospheric pollution caused by vehicles running on petro products are perturbing the researchers to find available and immediate alternative to fossil fuels.
The physical and combustion properties of vegetable oils are close to petro-diesel fuel and in this context, vegetable oils can stand as an immediate candidate substitute for stored fuels. Vegetable oils are produced from processing of seeds of various plants and thus Renewable in nature.
However due to inherent high viscosity and low volatility vegetable oils would pose problems such as fuel flow and poor atomization and constraining their direct use in engines without any modifications.
In the present investigation effect of supercharging is studied on the performance of a direct injection diesel engine with the use of untreated cottonseed oil.
Performance of the engine is evaluated in terms of break specific fuel consumption, exhaust Gas Temperature and smoke Density. It is observed that when cottonseed oil is used as a fuel, there is a reduction in BSFC of about 15% when the engine is run at the recommended injection pressure and supercharging pressure of 0.4 bar g in comparison with the engine operation run under naturally operated condition.
INTRODUCTION:
With the exponential growth of automotive vehicle population and increased stress on industrialization in developing countries, the impact of the twin problems of exhaust emission and the depletion of precious foreign exchange reserves for importing nonrenewable petroleum crude and products to keep the vehicles moving will indeed be very severe. The atmospheric pollution in major cities due to automobiles has already reached alarming levels.
Oil technologists predict that over the next several decades plant based oils will become just as essential for the transportation industry as fossil fuels like gasoline and diesel oil are today.
Vegetable oils are mixtures of fatty acids-molecules that contain carbon, hydrogen, and oxygen atoms. The fatty acids present in it may be saturated, mono-unsaturated, or poly-unsaturated. The greater the number of the double bonds, the more easily the compound reacts with oxygen from the air and goes bad, as kitchen fats and oils do after months on the shelfs.
Intensive search is being carried out in developing diesel engine fuels and lubricants based on vegetable oils. Due to high viscosity of vegetable oils, they interfere with fuel jet penetration, atomization and results in higher fuel consumption and leaves gummy deposits on the engine components upon combustion.
Barsic et al. [1] studied the performance and emission characteristics of a DI naturally aspirated diesel engine when operated on 100%sun flower oil, 100%peanut oil and 50% (by vol.) mixtures of either sun flower oil or peanut oil with #2 diesel oil (i.e. diesel fuel with less than 0.01%sulphur by weight) and compared results with base line results obtained using #2 diesel fuel. They adopted a rotary fuel injection pump and with fuel flow adjusted to provide equal fuel energy input and observed that the engine power and thermal efficiency decreased slightly and emissions increased marginally. The attributed reasons were higher densities, higher viscosities, relatively lower heating values and thermal cracking of vegetable oil fuel droplets at elevated temperatures.
RESULTS AND DISCUSSION:
The test results obtained in the above experiments are discussed below.
The recommended fuel injection pressure of the engine under consideration is 180 bar.
Effect of supercharging can be observed in fig. 1, for different supercharging pressures at the recommended fuel injection pressure. It is evident from the fig. That as the supercharging pressure is increased the BSFC is gradually lowered and the lowest values of BSFC are observed for supercharging pressure of 0.4 bar g. variation of exhaust Gas temperature with BMEP is plotted in fig. 2 at an injection pressure of 180 bar for different supercharging pressure. The exhaust temperature are lower at a supercharging pressure of 0.4 bar g indicating lower exhaust gas losses supporting the lower BSFC values observed in fig. 1 with this supercharging pressure.
CONCLUSIONS:
1. With increase in supercharging pressure the performance of the engine is gradually improving while maintaining the recommended injection pressure with cottonseed oil as fuel. There is a reduction of about 15% in BSFC at full load with a supercharging pressure of 0.4 bar g compared to naturally operated condition.
2. Supercharging is essential when we want to adopt untreated vegetable oils for developing the power with a low specific fuel consumption compared to diesel operation.
Percentage reduction in smoke density is more as the supercharging pressure is increased and engine performance with untreated vegetable oils can be regarded as eco-friendly operation