Horsepower What it is and how it works'

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HorsepowerWhat it is and how it works.

• Welding and Small Gas Engines

Original Power Point Created by Eric
Haselhurst Modified by Georgia Agricultural
Education Curriculum Office June 2002
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The History of Horsepower

• The term was invented by James Watt in the
  1700s.
• He wanted to be able to talk about the power
  developed by horses used in coal mines.
• He determined that the average horse could
  complete 33,000 ft-lbs.. Of work in one minute.

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The History of Horsepower

• This unit of measure is still used today for
  cars, lawnmowers, and vacuums.
• To further explain HP, a horse exerting one HP
  can raise 330 lbs. of coal 100 ft in a minute.

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Measuring Horsepower

• You can measure horsepower by using a
  dynamometer.
• This machine places a load on an engine at
  different RPMs and measures torque which is
  converted to HP.
• The formula TorqueRPMs/5252

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Measuring Horsepower

• The following graph is an example of a typical
  horsepower curve of an automobile.

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Measuring Horsepower

• What can be learned from these graphs?
• It shows peak horsepower at specific RPMs as well
  as torque.
• Example - 320 HP _at_ 6500 RPM
• 290 ft-lbs. torque _at_ 5000 RPM
• these figures are for the 1999 Shelby Series 1.
• To be first off the line at a stop light, rev
  your engine to the RPMs for maximum HP and dump
  the clutch.

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How to increase Horsepower

• Change your computer chip
• Increase air flow- bigger air filters, blowers
• Increase exhaust flow- bigger pipes, mufflers,
  headers
• Change heads and cams- 4 valve heads improve
  intake and exhaust flow
• Add turbo and or super chargers

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How to increase Horsepower

• Cool the incoming air- the hotter the air, the
  less it will expand when combustion takes place
• Make everything lighter- aluminum is a popular
  material
• Increase the compression ratio
• Increase displacement- cubic inches
  V-6 vs. V-8

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References
www.howstuffworks.com