Hello again, and welcome back to another busy installment of the ABC of EVs. Today we’re taking a look at the e-Pedal.
What are we talking about today?
So let’s do a whirlwind summary of what we actually mean by e-Pedal. Well, essentially, we’re talking about One Pedal Driving. And what that means is that you can drive the car without even having to touch the brake pedal! Yes, the car will brake itself. If you want the car to accelerate, you press the accelerator. If you want the car to slow down, then you release the accelerator. And if you want to coast along, then you simply modulate the brake pedal somewhere in between. But if you want the car to come to a complete stop, release the accelerator and the car will slow all the way down itself.
Some EV drivers may find that they can go out for a drive of tens or even a couple of hundred miles, and never once touch the break pedal. But that’s not to say that there is no brake pedal at all! Don’t worry, it’s still there. If there’s an emergency situation, you can always stamp on the brake pedal to stop quickly!
We’ll mention the Nissan LEAF firstly because although other cars have one-pedal driving, it was Nissan that coined the term e-Pedal that has become synonymous with one-pedal driving. Nissan were rightly proud of their new system. Previously the LEAF just had two modes of Regenerative Braking….D mode or a stronger B mode. But with the e-pedal they used a system where strong Regen slowed the car down when you lifted off the gas. And when the car slowed down to a level where Regen wasn’t that effective, the friction brakes came in to assist and bring the car to a complete stop.
The LEAF isn’t the only car that can bring itself to a complete stop. Take the Honda e for example. It also has a mode selector that turns the car into a full one-pedal system, and will bring you to a complete halt when you lift off the accelerator.
How does it work?
So let’s jump into a little bit more detail before we move on to a couple of other examples. Some of you may well be wondering what this term Regenerative Braking is. We won’t go into that much detail now as we made a full video about it a few weeks ago that you can check out if you wish.
So, when you ease off the accelerator, you use the energy of the moving car to generate electricity to go back into the battery by slowing the car down. The more you ease off the accelerator, the more Regen you get. Some cars can Regen at very strong levels, well beyond the 30kW or so that the earlier LEAFs could.
But as the car gets close to walking pace, the motor can’t Regen at the same level. So to bring the car to a complete stop, then it knows to begin to use the standard friction brakes to finish the job.
It’s at this point of blending that the system is most impressive. The car has to figure out how much brake pressure is needed and blend the force of friction brakes with the decreasing level of Regen so that there is little change in the braking sensation. Ideally, the driver doesn’t even know that the friction brakes have been applied.
Is it useful?
That sounds great Martyn, some of you are saying, but is it just a gimmick? Is it of any use? Well, most EV drivers love Regen, and those that have one pedal driving swear by it! They love it. Especially in heavy traffic. It can be so tiring using the clutch, accelerator and brake pedal! Even drivers of automatic cars have to keep moving between the accelerator and brake pedal. But in a car with something like an e-Pedal, all you have to do is release the accelerator, sit back and wait for the traffic to move again! The car will even hold itself in position if you’re on an incline or heading down hill.
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