Specific Fuel Oil Consumption (SFOC) Definition,Formula And Calculation

Specific Fuel Oil Consumption Definition

           Consumption of fuel oil per unit energy at out put shaft is known as Specific fuel oil consumption.Unit of specific fuel oil consumption is Kg/kWh or g/bhph .Or we can define in another way ie, mass of fuel oil consumed per average shaft power developed by the engine at the same time
Specific fuel oil consumption= Mass of fuel consumed per hour/break power in that particular hour


Detailed Specific Fuel Oil Consumption calculation for diesel engine SFOC Calculation

SFOC = ( Co x D x 10^6 )/(h x Pe)
               
where:
Co = Fuel oil consumption over the period (m^3)
D = Corrected gravity (t/m3)
h = Measuring period, hours
Pe =Brake horse power, bhp

Specific Fuel Oil Consumption Calculation

      For finding Specific fuel oil consumption we should know all the values which is required for the above formula

     >Take fuel oil  flow meter reading for specific time interval usually take one hour period. ie h=1hr
     >Difference between two reading gives you the Volume ie Co
     >Density of  fuel oil is in bunker delivery note or in sample test result using this value calculate the density of fuel oil at the temperature near the low meter D
Temperature corrected Density D= (Density of Fuel Oil @ 15 degree Celsius) * [1- {(T-15) * 0.00064}] 
    >Calculate the shaft power at the given interval Pe . Shaft power is calculated by the help of dynamometer or using fuel index and RPM you can find out the break power from the graph given in manual.   

For example 
h          =1hr
Co       =1.3m3
D119   =0.94t/m3
Pe        =8,200 bhp

           SFOC = ( Co x D x 10^6 )/(h x Pe)

                      =149.03g/bhph