NeilBlanchard
Well-known member
- Joined
- Oct 11, 2014
- Messages
- 619
A typical car with a Cd of ~0.34 has a bit over 50% of the load on the drivetrain - at 30MPH.
The drag from aerodynamic flow increases by the square of the speed. So, at 55MPH the aero drag is ~78%.
Here is an online calculator for this: http://ecomodder.com/forum/tool-aero-rolling-resistance.php
Aerodynamic drag is a total loss. Which is why aero drag is more important than vehicle weight. Because we have two ways to reclaim some of the kinetic energy of the moving car: the best way is to use the kinetic energy to do what it is already doing - moving the car forward. The second way is to use regenerative braking - when you need to slow the car down. Regen is always going to be less efficient than coasting because regen can only reclaim some of the kinetic energy as electricity, because the motor and charger and the battery each have losses.
I know it is possible to greatly increase the efficiency of a car. I have been averaging ~50% above the EPA rating on my ICE car (2005 Scion xA) for over 5 years. I have lowered the Cd of my car from ~0.31 to ~0.26 - I did a coastdown test, and I have made several improvements since then. One of which I added side view video mirrors in place of the "paddle" optical mirrors. They are backup video cameras with ~140° view angles and I have two 7" LED backlit monitors side by side right in front of me. I have virtually no blind spots on the sides of the car. And this reduces both the frontal area (by about 1 sq ft) and it reduces the Cd, as well.
I have a 4/5ths grill block. I have smooth wheel covers. I have front wheel skirts to close the gap between the wheel and thee wheel opening. I have rear wheel skirts, and strakes. I have Kamm panels on the sides and the top of the hatch. I need to add a partial belly pan in the back, and complete the Kamm back with a panel under the rear bumper.
I don't think we can get that much of an improvement on the Leaf, because the Leaf is already so much more efficient than any ICE. My spouse and I together are already averaging 2.5X better energy efficiency than I am on my aero modded Scion xA.
So, has anybody here done any aerodynamic mods to your Leaf?
The drag from aerodynamic flow increases by the square of the speed. So, at 55MPH the aero drag is ~78%.
Here is an online calculator for this: http://ecomodder.com/forum/tool-aero-rolling-resistance.php
Aerodynamic drag is a total loss. Which is why aero drag is more important than vehicle weight. Because we have two ways to reclaim some of the kinetic energy of the moving car: the best way is to use the kinetic energy to do what it is already doing - moving the car forward. The second way is to use regenerative braking - when you need to slow the car down. Regen is always going to be less efficient than coasting because regen can only reclaim some of the kinetic energy as electricity, because the motor and charger and the battery each have losses.
I know it is possible to greatly increase the efficiency of a car. I have been averaging ~50% above the EPA rating on my ICE car (2005 Scion xA) for over 5 years. I have lowered the Cd of my car from ~0.31 to ~0.26 - I did a coastdown test, and I have made several improvements since then. One of which I added side view video mirrors in place of the "paddle" optical mirrors. They are backup video cameras with ~140° view angles and I have two 7" LED backlit monitors side by side right in front of me. I have virtually no blind spots on the sides of the car. And this reduces both the frontal area (by about 1 sq ft) and it reduces the Cd, as well.
I have a 4/5ths grill block. I have smooth wheel covers. I have front wheel skirts to close the gap between the wheel and thee wheel opening. I have rear wheel skirts, and strakes. I have Kamm panels on the sides and the top of the hatch. I need to add a partial belly pan in the back, and complete the Kamm back with a panel under the rear bumper.
I don't think we can get that much of an improvement on the Leaf, because the Leaf is already so much more efficient than any ICE. My spouse and I together are already averaging 2.5X better energy efficiency than I am on my aero modded Scion xA.
So, has anybody here done any aerodynamic mods to your Leaf?