dm33
Well-known member
The Leaf seems to get particularly poor mileage at high speeds. Although much of this can be attributed to normal air resistance, the power drain seems to be more than that alone would explain. The Chevy Volt doesn't seem to have this severe a range drop at highway speeds. On the Tesla website, they have a calculator which estimates range for city and highway where you can set the speed. They estimate a higher range for highway at 65mph than in the city. The Leaf is no where near the same. I find that going slower gets much higher range.
My assumption is that the reason for the inefficiency is that the motor is over-revving. Reaching RPMs that are close to its limit and becoming less efficient.
The Leaf has plenty of torque from a stop. On the 2013 model Nissan apparently thought it had too much torque. They actually programmatically reduce the torque from a start. I think they did this to try to eek out better range. Similar to ECO, it just alters habits to use less power from a start.
However, theres another alternative that could help both problems. A reduction gear is used to reduce the RPMs from the motor to the wheels. The current end to end ratio is 7.9377.
If the reduction gear ratio was lowered it would adjust both items above. Most importantly it would allow the motor to run at lower RPM for improved efficiency at high speeds. It would also lower the effective torque from a start.
The worst effect I can think of is that it would lower the effective torque throughout the powerband making the car feel somewhat less powerful. Maybe trying to do a higher torque motor like the Chevy Spark would help.
Thoughts? Any engineer types out there with design knowledge of the Leaf's powertrain?
My assumption is that the reason for the inefficiency is that the motor is over-revving. Reaching RPMs that are close to its limit and becoming less efficient.
The Leaf has plenty of torque from a stop. On the 2013 model Nissan apparently thought it had too much torque. They actually programmatically reduce the torque from a start. I think they did this to try to eek out better range. Similar to ECO, it just alters habits to use less power from a start.
However, theres another alternative that could help both problems. A reduction gear is used to reduce the RPMs from the motor to the wheels. The current end to end ratio is 7.9377.
If the reduction gear ratio was lowered it would adjust both items above. Most importantly it would allow the motor to run at lower RPM for improved efficiency at high speeds. It would also lower the effective torque from a start.
The worst effect I can think of is that it would lower the effective torque throughout the powerband making the car feel somewhat less powerful. Maybe trying to do a higher torque motor like the Chevy Spark would help.
Thoughts? Any engineer types out there with design knowledge of the Leaf's powertrain?