Regen Paddle Braking

[Lowell_Greenberg]

Since owning the Clarity, I am impressed with the way regen contributes to EV range. I find myself also using the paddles quite a bit to maximize regen even further. My question is whether by using the paddles frequently, I am contributing to greater system wear. While it is not really analogous, I know that using paddle shifters with an automatic or CVT probably can effect transmission life. The Clarity paddles seem purely electronic and I am unclear exactly how they work in the car to maximize regen.

Sent from my SM-G975U using Tapatalk

 

[KentuckyKen]

First of all you can get the same and even more regen with the pedal as long as you don’t brake excessively hard. And the paddles will not wear out anything in the car; all they do is engage different levels of regen electronically and don’t even engage the physical brakes.
Paddle to your heart’s content. Just realize that under normal deceleration, you are not getting any more regen than pedal braking.

I kind of make the analogy to ECON vs. SPORT. ECON without going past the detent will guarantee no ICE, while SPORT might call for ICE if you get too lead footed. Both can achieve all EV driving, but one guarantees it and the other requires some operator effort.
Similarly, the paddle guarantees no physical braking (until last 5 mph to full stop) while the pedal can too but only if the operator minds his braking force.
Both will get you regen, but of course the best economy is moderate acceleration and anticipating the stop ahead so you need as little braking/regen as possible since it can’t recapture 100% of the energy expended. Remember, there is no coasting or pulse and glide in the Clarity since whenever you take your foot off the go pedal you are in at least the lowest one chevron regen (even if the chevron is not illuminated).

 

[stacey burke]

Since owning the Clarity, I am impressed with the way regen contributes to EV range. I find myself also using the paddles quite a bit to maximize regen even further. My question is whether by using the paddles frequently, I am contributing to greater system wear. While it is not really analogous, I know that using paddle shifters with an automatic or CVT probably can effect transmission life. The Clarity paddles seem purely electronic and I am unclear exactly how they work in the car to maximize regen.

Sent from my SM-G975U using Tapatalk

If you use sport the regain will remain after the stop. It can be very much like one pedal driving in other EVs. All other modes the regain goes back to 1 as soon as you press the "gas" pedal.

 

[ClarityBill]

First of all you can get the same and even more regen with the pedal as long as you don’t brake excessively hard. And the paddles will not wear out anything in the car; all they do is engage different levels of regen electronically and don’t even engage the physical brakes.
Paddle to your heart’s content. Just realize that under normal deceleration, you are not getting any more regen than pedal braking.

I kind of make the analogy to ECON vs. SPORT. ECON without going past the detent will guarantee no ICE, while SPORT might call for ICE if you get too lead footed. Both can achieve all EV driving, but one guarantees it and the other requires some operator effort.
Similarly, the paddle guarantees no physical braking (until last 5 mph to full stop) while the pedal can too but only if the operator minds his braking force.
Both will get you regen, but of course the best economy is moderate acceleration and anticipating the stop ahead so you need as little braking/regen as possible since it can’t recapture 100% of the energy expended. Remember, there is no coasting or pulse and glide in the Clarity since whenever you take your foot off the go pedal you are in at least the lowest one chevron regen (even if the chevron is not illuminated).

KentuckyKen:

I keep hearing that friction brakes do not engage with light pedal pushes. Is this documented somewhere?

The brakes seem to be normal hydraulic brakes, with regen on top: I do not hear the anti-lock system releasing the brakes during initial braking for regen. Normal hydraulic brakes begin caliper movement with the slightest touch, to be sure pedal travel is not excessive. The brakes will work with complete electrical failure, so this implies a direct hydraulic link. The brakes may not fully engage, but there is movement in the friction brakes.

I guess there are degrees of engagement, but it seems misleading to say there is no friction braking when using the pedal 'lightly'.

 

[AaD]

On the graph that someone posted here highlighting Honda's increased efficiency in the regen system it did look like the friction brakes did briefly engage while regen is ramping up, but I'd wager that the net difference in gain is insignificant in the real world. What does make a difference is avoiding regen (or braking) altogether when you don't need it. With the clarity it means you have to get a feel for how much to feather the accelerator to stay at a near coast rather than allow it to sink into regen when you don't need it. Any time you are slowing the car unnecessarily you are wasting energy, regen or not. I would bet the EPA range would be 50 plus if they just got rid of the default regen and let the car coast - I've managed over 70 miles of real world driving this way.

 

[KentuckyKen]

KentuckyKen:

I keep hearing that friction brakes do not engage with light pedal pushes. Is this documented somewhere?

The brakes seem to be normal hydraulic brakes, with regen on top: I do not hear the anti-lock system releasing the brakes during initial braking for regen. Normal hydraulic brakes begin caliper movement with the slightest touch, to be sure pedal travel is not excessive. The brakes will work with complete electrical failure, so this implies a direct hydraulic link. The brakes may not fully engage, but there is movement in the friction brakes.

I guess there are degrees of engagement, but it seems misleading to say there is no friction braking when using the pedal 'lightly'.

Try looking at the amount of regen when slowing down both ways; i.e. how much the power bar goes down into the green. I notice two things. First, for approximately the same deceleration rate (per my uncalibrated Mark 1 inner ear and body movement) I see about the same regen. Secondly, I notice I can get even more regen with the pedal than I can with max paddle or 4 chevrons.

So IMHO, Honda biased the braking to use regen primarily and predominantly whenever possible and then use the friction brakes if necessary due to more braking being called for than regen can handle. And of course it transitions to all friction during the final approach a full stop

And sadly none of this (and much more) is documented anywhere. Even though a few Honda tech articles have been accessed and shared, we are all still speculating and attempting to reverse engineer all this wonderful tech that Honda is so secretive of. So every one has an opinion and must use a little logic and common engineering sense, make inferences from observation, and stay within the bounds of the tech articles that we do have knowledge of. So please don’t think I’m posting with the intent of calling it the Holy Writ according to Honda. Far from it. I and many others are just trying to fit all the pieces of the tech puzzle together as best we can.

And to add to the confusion, Honda engineered what I think is the best regen/braking system currently available. It’s so seamless a transition between regen and friction that it’s almost impossible to tell it when it occurs and what the ratio is.

So we enjoy a technological marvel that can be rather frustrating to figure out. But in any case I expect the brake pads and rotors to go 100,000 miles or more like in other EVs with regen since they are used to a far lesser degree. And I’ve gotten over my peddle-paddle phobia.

 

[ClarityBill]

IMHO:

I tend to believe that Honda may have sacrificed a little brake pad and rotor life, to achieve the smooth transition that everyone brags about. While we are all expecting spectacular brake life, we are actually experiencing a simpler system that transitions well. It will still give great pad life, but not Tesla great.

If I were to build a system: The hydraulic brakes would be a normal system, going from no brakes to full stop in pedal movement of 0 to 100%. I would then install regen braking system that would engage from no brakes to full regen in pedal movement of 0 to 30%. (Friction brakes at 30% before reaching full regen - who could tell?)

The paddles would effectively make the regen braking begin engagement at pedal movement of negative 30%, and bring in regen braking faster than possible with the pedal.

It seemed that people were suggesting not to use the paddles, without loss of regen energy savings: I don't think the system is that complicated.

It seems like some of this reverse engineering is making things much more complicated than they have to be.

 

[Sandroad]

I'll guess there are no downsides in longevity for constant use of regeneration. The greater the regeneration amps, the greater the stresses on the generator (bearings, etc), but it's made for that and will no doubt last a while anyway. Paddle away!

I'm convinced the friction brakes don't apply the pads under light braking until the final stop. Our braking system is very sophisticated. @AnthonyW posted the pdf of the electro-mechanical servo system that's really remarkable in its engineering and application.

https://www.insideevsforum.com/comm...-for-2018-clarity-phev.2183/page-5#post-33875

Use of regeneration is the most efficient way to drive. Regen is the reason hybrids are more efficient (better mpg) that their non-hybrid counterparts. If you look at the entire driving cycle, the kinetic energy of the moving car is captured during regeneration for use during the subsequent acceleration. It's of course not 100% efficient because of system losses, but overall it's better to use regeneration than not.

 

[Mark W]

Why would Honda have the friction brakes applied under light braking if the battery is not near full?

 

[KClark]

And to add to the confusion, Honda engineered what I think is the best regen/braking system currently available. It’s so seamless a transition between regen and friction that it’s almost impossible to tell it when it occurs and what the ratio is.

I tend to agree with ClarityBill, I'm guessing that the transition from regen to friction brakes when you step on the brakes is so seamless is because there is a little bit of friction braking occurring no matter how lightly you step on the pedal. Engaging friction brakes, even very lightly, from the initial application of the pedal would make it seem seamless to the driver since there never is a condition when the friction brakes aren't engaged. But, like I said, that's just my guess.

 

[insightman]

I'm guessing that the transition from regen to friction brakes when you step on the brakes is so seamless is because there is a little bit of friction braking occurring no matter how lightly you step on the pedal.

The Clarity's brake system is so sophisticated it has a Pedal Feel Simulator. What you feel is what Honda's engineers want you to feel, regardless of what's actually happening with the brakes and regen through the traction motor.

 

[dnb]

If you use sport the regain will remain after the stop. It can be very much like one pedal driving in other EVs. All other modes the regain goes back to 1 as soon as you press the "gas" pedal.

Even with 4 bars my car doesn't come close to stopping and will happily drive around at a few mph. I always have to manually break for stop signs unless I want to go a whole block with no gas... its fast to slow down but then doesn't get close to stopping even after a long time. I use it for yield signs / roundabouts but its worthless for stop signs or traffic lights.

 

[insightman]

I keep hearing that friction brakes do not engage with light pedal pushes. Is this documented somewhere?

Our Clarity wasn't driven for two weeks and the front brake rotors acquired some rust. Now I can hear a periodic "swish-swish" noise when driving at low speeds. I assume if I start using the friction brakes more (and harder), I will wear the rust off the rotors--I sure hope so. The sound of the rotor rust bugs me.

However, there is an informational benefit to this audible brake-pad interaction: It's now easy to tell when the brake calipers cause the brake pads to engage. What I've realized is that I can hear the brake pads clamp down on the rotor at the lightest possible touch on the brake pedal. So the first part of the brake pedal's travel DOES engage the friction brakes as well as activating regen braking.

 

[Groves Cooke]

So IMHO, Honda biased the braking to use regen primarily and predominantly whenever possible and then use the friction brakes if necessary due to more braking being called for than regen can handle. And of course it transitions to all friction during the final approach a full stop

I totally agree. When the battery is completely charged and you use the brake pedal, there is very little regen (dipping into the green) compared to when the battery is more depleted.

 

[2002]

I totally agree. When the battery is completely charged and you use the brake pedal, there is very little regen (dipping into the green) compared to when the battery is more depleted.

Maybe the 2020 model will include dynamic braking cooling fans

 

[2002]

I get what I initially thought was a random beep sometimes when I use the paddles, a relatively loud and long beep when I first press the paddles. I eventually figured out that it is informing me that ACC has turned off, if it was on when I pressed the paddles. I confirmed this by changing to non-ACC cruise, in that case I don't get the beep when using the paddles. I have searched high and low but have not been able to find a way to turn off the beep. It doesn't do a similar beep when you press the brake pedal even though that also turns off ACC, but I guess they figure everyone already knows that, but people might not realize that the paddles also turns it off. But I don't need the reminder every time I use the paddles.