[Nishanth]

I'm writing a research paper on ways to reduce aerodynamic drag on automobiles and I have a doubt.
I have managed to reduce the drag coefficient of an automobile from 0.6 to 0.48. I want to know how to calculate the fuel consumption for both the cases assuming all the other factors remains the same. Is there a direct relationship between the coefficient of drag and fuel consumption?

In simple words, let the drag co-efficient of a certain vehicle be 0.6 and assume I managed to reduce it to 0.5. What will be the fuel consumption for both of my cases assuming the velocity of the vehicle, density of air, rolling resistance, engine efficiency, drivetrain efficiency all remain constant.

Can you please provide me with equation(s) to calculate the fuel consumption with proof so that I can cite the same on my research paper!

Thank you.

[flotus1]

The impact of aerodynamic drag on fuel consumption depends on the ratio of aerodynamic drag to all other forms of resistance. For constant velocity on a flat surface, only rolling resistance is relevant. And of course, aerodynamic drag is proportional to velocity squared, while rolling resistances are mostly linearly proportional to velocity.
Even if you only want to make a relative statement, i.e. 10% reduced fuel consumption, you still need to know the velocity, and the type of vehicle, more precisely its rolling resistance. Large, heavy vehicles generally have a higher ratio of rolling resistance to drag, compared to lighter vehicles.

[Nishanth]

Originally Posted by flotus1

The impact of aerodynamic drag on fuel consumption depends on the ratio of aerodynamic drag to all other forms of resistance. For constant velocity on a flat surface, only rolling resistance is relevant. And of course, aerodynamic drag is proportional to velocity squared, while rolling resistances are mostly linearly proportional to velocity.
Even if you only want to make a relative statement, i.e. 10% reduced fuel consumption, you still need to know the velocity, and the type of vehicle, more precisely its rolling resistance. Large, heavy vehicles generally have a higher ratio of rolling resistance to drag, compared to lighter vehicles.

Let's say my co-efficient of rolling resistance is 0.006 and the vehicle is moving with a constant velocity 80 Km/h (22.22m/s). Now, what is my fuel consumption?