Performance factors

• How will you figure out the fuel efficiency of the vehicle without driving it?

• What variables will go into the equation/mathematical model? Mass Aerodynamics Rolling Resistance Engine/Fuel/Components

Aerodynamics

Drag coefficient

The average modern automobile achieves a drag coefficient of between 0.30 and 0.35.

Drag coefficient x Frontal area = drag area

Rolling Resistance (rolling friction)

5-15% of fuel used to overcome RR Which contributes less RR?

Rubber vs Steel? Concrete vs Sand? Big or small wheel?

Mechanical energy transferring to?

http://www.greencar.com/articles/low-rolling-resistance-tires-can-better-mpg.php

Rolling Resistance (rolling friction)

Factors Deformation of surface & object

(hysteresis) Wheel radius Surface adhesion Relative micro-sliding

Rolling Resistance (rolling friction)

Energy Independence and Security Act of 2007

Engine/Fuel/Components

Engine Thermodynamic efficiency What percent of fuel energy becomes

kinetic? Mechanical friction (transmission

losses, etc.) Components

Air Conditioner Power Steering Cooling Electrical Systems

http://en.wikipedia.org/wiki/Fuel_economy_in_automobiles

Fuel Sources

Gasoline Diesel Biodiesel Compressed Natural Gas (CNG) Electricity

Oil

Using fuel

How do we put the fuel to work? Combustion

New technology

New Technology