Patent ID: 8332121

Claim:
A method of determining a vehicle efficiency factor (E) for a vehicle powered by an internal combustion engine, the engine powered by a fuel, the method comprising: determining a fuel chemical energy input (F), a change in a kinetic energy (K), a change in a potential energy (P), a magnitude of aerodynamic frictional losses (A), a magnitude of mechanical frictional losses (M), and a magnitude of braking frictional losses (B) of the vehicle over a predetermined time interval; and determining the vehicle efficiency factor (E) for the predetermined time interval based on a comparison between a total energy input and a total energy output, the total energy input including the fuel chemical energy input (F), the total energy output including the change in the kinetic energy (K), the change in the potential energy (P), the aerodynamic frictional losses (A), and the mechanical frictional losses (M) of the vehicle.