ChatterBank1 min ago
Hp Calculation Help Needed Please
11 Answers
An engine crankshaft has a throw of 17mm.The piston exerts a force of 800kg at 2500rpm.What is the theoretical hp?
Answers
Circumferenc e = 0.107m Force = 8000N Work = Force X Distance = 8000 X 0.107 = 855J Crankshaft frequency = 2500/60 = 41.7 Hz Crankshaft period = 1/41.7 = 0.024 second Power = Work/Time = 855/0.024 = 35625 Watts = approx 48 Horsepower This assumes the piston is exerting a constant force of 8000N for the entire 360 degrees of revolution of the crankshaft which is...
21:14 Sun 08th Sep 2013
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Circumference = 0.107m
Force = 8000N
Work = Force X Distance = 8000 X 0.107 = 855J
Crankshaft frequency = 2500/60 = 41.7 Hz
Crankshaft period = 1/41.7 = 0.024 second
Power = Work/Time = 855/0.024 = 35625 Watts = approx 48 Horsepower
This assumes the piston is exerting a constant force of 8000N for the entire 360 degrees of revolution of the crankshaft which is unlikely.
Force = 8000N
Work = Force X Distance = 8000 X 0.107 = 855J
Crankshaft frequency = 2500/60 = 41.7 Hz
Crankshaft period = 1/41.7 = 0.024 second
Power = Work/Time = 855/0.024 = 35625 Watts = approx 48 Horsepower
This assumes the piston is exerting a constant force of 8000N for the entire 360 degrees of revolution of the crankshaft which is unlikely.
An adjustment to teddio's formula is needed to account for the average proportion of a revolution that is a power stroke and sine correction for the conversion of linear motion to rotation. In addition the connecting rod angle changes throughout the power stroke so the 800kg force is only realised at the top and bottom of the stroke when no rotary motion is imparted. The length of the connecting rod has to be known too.