Miles Per Gallon

A Presentation by Thomas Brath and Jack Hanington

All rights reserved, Copyright 2008 ®

Definition of MPGs The Definition of Miles Per Gallon is the

distance (in miles) a vehicle can travel on one gallon of fuel. For vehicles that operate on fuels that cannot be measured in gallons (electricity, natural gas, hydrogen), the gasoline gallon equivalent is employed to give a reference point for comparison.

The Miles Per Gallon testLike a lot of things in the United States, gas

mileage is mandated by federal programs. In this case the highway and city gas mileage is

regulated under the roof of the EPA (Environmental Protection Agency) due to the

release of carbon dioxide into the atmosphere by vehicles. It is also investigated by the

department of energy.

How does the E.P.A test M.P.G?

Brace Yourself!!!!!

How the E.P.A tests m.p.g.

• In the laboratory, the vehicle's drive wheels are placed on a machine called a dynamometer that simulates the driving environment.

• The energy required to move the rollers can be adjusted to account for wind resistance and the vehicle's weight.

Tesla Roadster

Factors that effect mpgs• Quick acceleration and heavy braking can reduce fuel economy by up to 33 percent

on the highway and 5 percent around town. New EPA tests account for faster acceleration rates, but vigorous driving can still lower MPG.

• Excessive idling decreases MPG. The EPA city test includes idling, but more idling will lower MPG.

• Driving at higher speeds increases aerodynamic drag (wind resistance), reducing fuel economy. The new EPA tests account for aerodynamic drag up to highway speeds of 80 mph, but some drivers exceed this speed (cough cough Tom)

• Cold weather and frequent short trips can reduce fuel economy, since your engine doesn't operate efficiently until it is warmed up. In colder weather, it takes longer for your engine to warm, and on short trips, your vehicle operates a smaller percentage of time at the desired temperature. Letting your car idle to warm-up doesn't help your fuel economy, it actually uses more fuel and creates more pollution.

• Running electrical accessories (air conditioner, radio, seat heater, ) decreases fuel economy. Operating the air conditioner on "Max" can reduce MPG by roughly 5-25% compared to not using it.

• Driving on hilly or mountainous terrain or on unpaved roads can reduce fuel economy. The EPA test assumes vehicles operate on flat ground.

• Using 4-wheel drive reduces fuel economy. Four-wheel drive vehicles are tested in 2-wheel drive. Engaging all four wheels makes the engine work harder and increases Fuel.