Problem 31. A four stroke 394mm bore and 534mm 534mm stroke single acting diesel diesel engine with four cylinders is guaranteed to deliver 350 Bhp at 300 rpm. The engine consumed 66.8 kg/hr of fuel with a heating value of 44,251 KJ/kg. Calculate indicated mean effective pressure in Kpa if mechanical efficiency is 89%. A. 450.8 Kpa
C. 345.6 Kpa
B. 234.5 Kpa
D. 643.2 Kpa
SOLUTION: Vd
= ∏/4 D²LNc
Vd
= ∏/4 (0.394)² (0.534) (
Vd
= 0.651 m³/sec
Brake Power = 350 (0.746) =
m
ŋ
m
x
Pmb x
2x60
) (4)
Vd
0.651
= 401.2 Kpa
Pmb
ŋ
Pmb
300
=
=
0.89 = Pmi
BrakePower IndicatedP ower P mb P mi
401.2 Pmi
= 450.8 Kpa
Problem 35. A certain diesel engine with with the following classification, 8 cylinder, 400mm 400mm x 600mm, four stroke cycle has a fuel consumption of 0.6 lbs/hp-hr based on 19,100 BTU/lb. Engine speed is 280RPM with an indicated mean effective pressure 130 psi. If the jacket water carries away an estimated 25% of the heat supply, find its capacity (gpm) required if the allowable rise is 40 F. ̊ A. 234
C. 242
B. 673
D. 292
SOLUTION:
Vd
= ∏/4 D²LNc
Vd
= ∏/4 (0.4)² (0.60) (
Vd
= 1.4074 m³/sec
280 2x60
Indicated Power = (130 x
) (8)
101.325 14.7
) (1.4074)
Indicated Power = 1,261.16 KW Indicated Power = 1,690.56 Hp mf
= 0.6 (1,690.56)
mf
= 1,014.336 lbs/hr
Heat Supplied =
mf Qh
= (1,014.336) (19,100)
Heat Supplied = 19,373,817.6 BTU/hr Heat gained by water = (0.25) (19,373,817.6) Heat gained by water = 4,843,454.4 BTU/hr Heat gained by water = 80,724.24 BTU/min Heat gained by water = 80,724.24 = mw
