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PERFORMANCE OF BIODIESEL COMPARED TO CONVENTIONAL DIESEL

FUEL IN STATIONARY INTERNAL COMBUSTION ENGINES

B.K. HIGHINA, I.M. BUGAJE  and B. UMAR

Department of Chemical Engineering, Department of Agricultural and Water Resources Engineering,

University of Maiduguri, Borno, Nigeria

Journal of Applied Technology in Environmental Sanitation

Volume 1 , Number 2 : 199 - 205 , August , 2011

ABSTRACT

                   In this study, the technical specification of an internal combustion engine

designed for diesel fuel was used for biodiesel. The changes in engine performance, and

cycle by cycle (CBC) variations were observed, and their causes were studied. When

biodiesel was used as the fuel, acceptable changes occurred in the performance values.

The maximum brake mean effective pressure (BMEP) obtained with the biodiesel was

slightly higher than that obtained with the diesel fuel, with the difference being just slight

under maximum power. While biodiesel increase the maximum engine power, it reduces

the brake specific fuel consumption. Changes of maximum cylinder pressure have

occurred at the same magnitude for both fuels for the same engine speeds. The best

engine performance for biodiesel operates at the engine speed of 2000 rpm to 2500 rpm.

The overall analysis has shown that biodiesel has potential as an alternative fuel in

conventional internal combustion engines.

 Growing concern regarding energy resources and the environment has increased interest in the study of alternative sources of energy. To meet increasing energy requirements, there has been growing interest in alternative fuels like biodiesel to provide a suitable diesel oil substitute for internal combustion engines. biodiesel produced from any source need to checked by checking its performance from the various available model that determines the performance of biodiesel.

OBJECTIVE:

The aims and objectives of this work are to check the performance of biodiesel

in a stationary internal combustion engine from developed models and to compare the performance of the biodiesel with conventional diesel fuel in a stationary diesel engine.

MATERIALS AND METHODS

The analytical experimental procedure was carried out using a four stroke CHANGCHAI diesel engine; model 2100, characterised biodiesel from peanut oil (ASTM 6751) and characterized conventional diesel fuel (ASTM 975)

Engine Performance Equations

Torque: measured by the dynamometer.

Input Power  is given by the

IP = mQnet (2)

Where:

IP = Input Power(kW )

Qnet = is the lower calorific value of the fuel.

The mass flow rate is calculated by multiplying the volumetric flow rate with density of the fuel

M=V/t  * 1 * 10^-3  * Ϭ* µ

Where:

m = Mass Flow Rate of Fuel (kg/s)

V = Volume Flow Rate of Fuel (cm3/s)

Ϭ= Density of Water (kg/cm3)

µ= Specific gravity (kg/cm3)

Brake mean effective pressure

Brake specific fuel consumption (BSFC)

BSFC =  m/BP

Where mass flow rate = fuel consumption (L/s) × Specific gravity (Kg/L)

RESULTS AND DISCUSSION

Fig. 1: Torque versus speed

The torque decreases as the engine speed increased. As the engine speed increases, the high initial torque will decrease. The maximum torque is reached for both fuels for speeds ranging from 1800- 2200rpm. However biodiesel produces a higher torque compared to conventional diesel fuel. Generally the torque reduces for every increase of speed.

Fig. 2: Break power versus speed

Biodiesel required a higher amount of brake power.

Fig. 3: Specific fuel consumption versus speed

There is a pattern showing that, between the range of 2000 and 2500 rpm, the fuel consumption is at its maximum; under that specific range, the fuel consumption of biodiesel is relatively higher than conventional diesel fuel.

Fig. 4: Efficiency versus speed

When input power decreases, the efficiency of the engine increases. Biodiesel proves to be more efficient than conventional diesel fuel in this range.

CONCLUSION

The maximum brake mean effective pressure (BMEP) obtained with the biodiesel was slightly higher than that obtained with the diesel fuel, with the difference being just slight under maximum power. While biodiesel increase the maximum engine power, it reduces the brake specific fuel consumption. Changes of maximum cylinder pressure have occurred at the same magnitude for both fuels for the same engine speeds. The best engine performance for biodiesel operates at the engine speed of 2000 rpm to 2500 rpm. The overall analysis has shown that biodiesel has potential as an alternative fuel in conventional internal combustion engines.

 By

Shivam  Martolia (114) (shivam.nitie@gmail.com)
PGDIE 42
NITIE