Generally, horsepower refers to the rate of doing work. In terms of cars, horsepower is the rate at which the engine of a car is able to perform its function. This term was first invented by James Watt. The Scottish engineer is known for his contribution to the improvement of steam engines.

As per the concept of Watt, one horse has the ability to perform 33,000 foot-pounds of work in one minute. For example, when a horse is made to raise coal out of a coal mine, by exerting 1 horsepower he can raise 330 pounds of coal to 100 feet in a minute; or 33 pounds of coal to 1,000 feet in one minute; or 1,000 pounds of coal to 33 feet in one minute. All these three situations will generate different horsepower. Therefore, it is clear that number of different combinations can be used to get a certain horsepower as long as the product is 33,000 foot-pounds in one minute. In the same way, auto manufacturers also choose various combinations of fuel and technologies in order to generate the expected horsepower.

Depending on the requirement, horsepower can be converted into a number of units. Some of the significant unit changes of horsepower include:

• 1 horsepower is equal to 746 watts.
• 1 horsepower over the time span of one hour is equal to 2,545 BTU (British Thermal Units). BTU is the amount of energy required to increase the temperature of 1 pound of water at 1 degree F.
• 1 BTU is equal to 1,055 joules, or 252 gram-calories or 0.252 food Calories.

Measurement of Horsepower

Typically, the horsepower of a car engine is measured with the help of a dynamometer. Dynamometer is a small automotive machine that is used to measure torque, rotational speed and power produced by a car engine. The method of measuring horsepower involves attaching the dynamometer to the engine. The former places a load on the latter and then measures the power that the engine produces against the load. The method helps to measure the load that a particular engine can handle at varied speeds.

This entry was posted on Tuesday, March 31st, 2009 at 11:27 am and is filed under Buying a Car. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.