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As electric cars firmly enter the mainstream, more and more debates are opening up about these vehicles and what they can and can’t do, which kinds of
www.greencarfuture.com
There's a lot wrong with that blog (it's hardly a research paper) and with your interpretation of it.
For starters, the blog opens with this statement:
"In short, regenerative braking is a technology whereby excess energy is recaptured from the standard braking process whereby it is then turned into kinetic energy that is transferred back to the car’s main battery system. The idea first emerged in hybrid cars as a way of extending their overall electric range and allowing for even greater fuel efficiency."
That is a very clear statement that use of regenerative braking enhances fuel efficiency overall.
The blog then goes on to describe coasting:
"In a regular gasoline car, people would use their gathered momentum
to keep the car moving forward [my emphasis] — albeit slowing continuously — instead of putting or keeping their foot on the gas pedal. This coasting has long been known as a fuel-saving method, and very useful when driving on highways, or when dealing with very slight forward downhill slopes. Let gravity do some of the work, right?"
This is not an argument that coasting is a more efficient means of
slowing a car. It is a description of how average speed can generally be
maintained --
i. e., "keep the car moving forward" -- by using coasting intermittently when a car is on a downhill slope or when the car's forward momentum can maintain sufficient speed for brief periods before having to reapply the gas.
Then we get to the areas where the blog is just plain wrong technically. For instance, it reads:
"In short, regenerative braking is a technology whereby excess energy is recaptured from the standard braking process whereby it is then turned into kinetic energy that is transferred back to the car’s main battery system."
No. "Standard braking" is friction braking. The energy that goes into the battery during regenerative braking is not energy from friction braking. It is energy derived from the forward momentum of the vehicle as it slows due to the motors being switched into generator phase.
The blog describes how regeneration is activated thus:
"Releasing the accelerator pedal would simply cause the electric motor to spin in the opposite direction automatically."
Again, a big time no. The motor does not "automatically" start spinning backwards in an EV when you lift off the accelerator pedal. What happens is that the electronic control unit of the car sends a signal to reverse
the direction of current flow in the motor, thereby reversing its magnetic field and causing it to function as a generator. The forward momentum of the car keeps the motor spinning in the same direction, but now resisting that direction of travel instead of propelling it. The direction of motor spin does not change during regenerative braking.
Also, the blog describes regenerative braking as "actively creating energy to pass back to the battery."
Once again, no. Regenerative braking does not "create" energy. Nothing since the Big Bang has done that. It recovers energy from the car's forward momentum and converts it into kinetic energy to be stored in the battery.
In short, this blog is a morass of misinformation and misunderstanding of what goes on with regenerative braking.