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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