In this post of mine I will be dealing with how to calculate the work done and power produced by an I.C. engine.
From Newton’s 2nd law we know the force equation:-
F=ma
We also know that:
Work Done=Force*displacement
Now by the definition of pressure we know that:
Pressure=Force per unit area Or P=F/A F=P*A
Using this value in Work Done equation above we get:
Work Done =P*A*Displacement
For a rectilinear motion distance =displacement So the above equation becomes:
W=P*A*Distance
We know that area*length = volume, replacing it in above equation:
W=P*V
Where P=pressure, V=volume, W=work done
So now coming to the point in an I.C. engine we can find out its volume of the cylinder easily by multiplying the Bore Diameter(D in the figure above) with the Stroke’s Length(d in the above figure) or we can get an approximate value by the cubic capacity of the engine. Pressure can be measured by a pressure gauge fitted in the cylinder. So with these two quantities we can now calculate the Work Done by the Engine.
Now we know that power is nothing but rate of work done per unit time. In short Power=Work Done /Time (unit of power =watts) .
So for an fixed time interval we can calculate the power produced by an I.C. engine.
Note: To convert the power calculated in horsepower we have to divide the result by 735 watts approximately.
Signing off:
MD.AFZAL ANSARI
2nd year B.E. MECHANICAL ENGINEERING