- FIND THE AREA OF THE INDICATOR DIAGRAM USING A PLANIMETER. LET THE AREA OF THE DIAGRAM BE “A”.
- NOW MEAN INDICATED PRESSURE,
M.I.P, P(i)= A/(L*C)
WHERE A= AREA OF INDICATOR DIAGRAM IN MM2
L= LENGTH OF INDICATOR DIAGRAM
C= SPRING CONSTANT OF THE INSTRUMENT
3. CALCULATE MEAN EFFECTIVE PRESSURE,
M.E.P, P(e)= P(i)-KT
WHERE KT= MEAN FRICTION LOSS
= 1 TO 1.5 DEPENDING ON ENGINE
4. CALCULATE CYLINDER CONSTANT,
K = 177968*D^2*S (BHP)
= 130900*D^2*S (KW)
WHERE D= CYLINDER DIAMETER (METRE)
S= PISTON STROKE (METRE)
5. CALCULATE INDICATED ENGINE POWER,
P(ep)= K*N*P(i)
WHERE N=R.P.M
6. CALCULATE EFFECTIVE ENGINE POWER,
P(eff)= K*N*P(e) (KW OR BHP)