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Ihp (P L A N N) / (2C) BHP Ihp - FHP Ihp X

Horsepower is defined as the amount of energy required to lift 33,000 pounds one foot in one minute. There are two types of horsepower in engines: indicated horsepower (IHP), which is the power developed in the engine cylinder, and brake horsepower (BHP), which is the actual power delivered by the engine to the drive shaft. BHP can be calculated by taking the IHP and subtracting the friction horsepower. Drawbar power is the power available at the rear hitch of a tractor for pulling and dragging, and can be calculated by taking the wheel axle power and subtracting power losses from slip and rolling resistance.

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Kristine Javier
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3K views2 pages

Ihp (P L A N N) / (2C) BHP Ihp - FHP Ihp X

Horsepower is defined as the amount of energy required to lift 33,000 pounds one foot in one minute. There are two types of horsepower in engines: indicated horsepower (IHP), which is the power developed in the engine cylinder, and brake horsepower (BHP), which is the actual power delivered by the engine to the drive shaft. BHP can be calculated by taking the IHP and subtracting the friction horsepower. Drawbar power is the power available at the rear hitch of a tractor for pulling and dragging, and can be calculated by taking the wheel axle power and subtracting power losses from slip and rolling resistance.

Uploaded by

Kristine Javier
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOC, PDF, TXT or read online on Scribd
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HORSEPOWER

• Defined as the amount of energy or work required to raise a weight of 33,000


pounds a height of one foot in one minute.
• 1 hp = 33,000 ft-lbs/min
INDICATED HP
• Is the power developed in the engine cylinder.
• This does not represent the actual useful power delivered by the engine.

• Ihp = PLANn/2C
Tractor Engine Indicated and Brake Horsepower Formula
IHP = [P L A N n ] / [ 2c ]
BHP = IHP – FHP
= IHP x xe
Where: P - mean effective pressure, psi
IHP - indicated horsepower, hp L - piston stroke, ft
BHP - brake horsepower, hp A - area of the piston, in2
FHP - friction horsepower, hp N - crankshaft speed, rpm
xe - engine efficiency, decimal n - number of cylinders

BRAKE & EFFECTIVE HP


• BP is the actual horsepower delivered by the engine to the drive shaft.
• BP = IHP – FRICTION
• EFFECTIVE HP is the final power delivered to the equipment. The difference
between IHP & EHP should be only around 25%.
• FRICTION POWER - is the power absorbed by the engine in generating itself
with a given speed and without any load.

• Mechanical efficiency – ratio of the BP over the IP x 100.

ME = (BP/IP) x 100

Sample Problem:

• Given: BP = 75 KW ME = 84%
N = 400 rpm
P = 760 KPa

4-stroke, cycle single cylinder


a) Determine the IP and
b) Size of the engine if B = S
B = bore (diameter of the piston);
S = stroke (length of travel of piston)
• Piston Displacement = the volume displaced by the piston in one stoke.
• Clearance Volume = volume left in the cylinder when the piston is at the TDC.

Sample Problem:
• What is the bore & stroke of an engine that has a CV of 160,000 mm^3, a
compression ratio of 5:1, a 575 mm flywheel, a piston speed of 5 m/s & a rim
speed of 45 m/s.

DRAWBAR POWER
• The power available at the drawbar hitch located at the rear of the tractor.
• Use for pulling, dragging, and other tractive works.

DP  FS DP = Pw – Pl
= Pw – (Ps + Pr
• DP = Drawbar Power Pw - wheel axle power
• F = Force Pl - power loss
Ps - power lost due to slip
• S = Speed Pr - power lost due to rolling
resistance

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