Brake coach, real or fake?

[PowerboostedF150]

Ok internet sleuths, I have an interesting observation on my ‘21 PB. I recently discovered you can turn on the brake coaching screens while in normal mode. Kinda cool. It adds the green range to the speedometer and puts up a message after stopping indicating how much energy has been recovered during that stop. So a hard stop might show 50% energy recovered, whereas a light stop would return 100% energy recovered.

I thought this was interesting because I know the brakes don’t always get used when stopping, only if it exceeds the regen force(depending on drive mode).

so I have noticed a mild chugging when slowing down off the highway exit ramps. I wanted to see if it was the rotors or something else. So when exiting the highway ramp, I put the truck in neutral and use the brakes (as normal) thinking the chugging would be more obvious. But the energy coach is still reporting the amount of energy recovered, with the truck in neutral and slowing down from 100km/h. So this makes me think the screen is not measuring amps or voltage or anything, but the deceleration force against the speed, and assuming it’s generating electricity to the battery.

anyone else notice this? And anyone else replace their rotors? I have 139,000km on mine, and the pads look ok still.

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[Goldeneye36]

That's interesting. I've never thought about how that meter got it's info and basically just trusted that it's reasonably accurate. The only anecdotal evidence I can provide is that any clunking I do feel seems to coincide with the bar showing friction braking coming in to assist the Regen on my EV Coach screen.

In theory, your experiment should result in the electric motor not connecting to the transmission output but I wonder if there is some programming going on where in N the electric motor is still connected to the transmission but disconnected from the engine vs the transmission being truly in Neutral. With everything being electronically controlled anything is possible.

I don't have access to my truck right now but anyone who else uses the ODBLink software and monitors those PIDs might be able to verify if the battery is truly charging in the scenario you posted.

 

[FaaWrenchBndr]

That's interesting. I've never thought about how that meter got it's info and basically just trusted that it's reasonably accurate. The only anecdotal evidence I can provide is that any clunking I do feel seems to coincide with the bar showing friction braking coming in to assist the Regen on my EV Coach screen.

In theory, your experiment should result in the electric motor not connecting to the transmission output but I wonder if there is some programming going on where in N the electric motor is still connected to the transmission but disconnected from the engine vs the transmission being truly in Neutral. With everything being electronically controlled anything is possible.

I don't have access to my truck right now but anyone who else uses the ODBLink software and monitors those PIDs might be able to verify if the battery is truly charging in the scenario you posted.

I don’t have a video of it, but yes, using the OBD II MX+ it does charge when you’re in the green zone while braking

 

[Tosh]

As I understand it, the electric motor/generator is always connected to the engine, and is disconnected from the transmission when in "N" (ProPower works when the truck is in "P", right?

So when in "N", the HV battery receives charging current. Perhaps less current than if you were in "D" while braking. I think the brake coach display is correct (though not necessarily accurate)

 

[Lefty665]

The transmission is behind the HV motor/generator. Neutral by the transmission will not affect the motor connection to the engine, that is controlled by a clutch between them.

Thus, disconnecting the HV motor from the wheels by placing the transmission in neutral would remove the ability of the HV motor to re-generate and slow the vehicle. That is not what is happening.

If shifting to neutral while moving instead disconnects the HV motor transmission from the engine instead of disconnecting the transmission from the wheels that would allow HV re-generation and braking as observed.

That is also consistent with comments that in normal or eco modes PBs do not get engine braking going down grades.

Seems likely the EV brake coach does a pretty good job of flagging when braking exceeds the capacity of EV re-generation and actually applies brakes. Not sure I'd bet much money on the accuracy of the display of the amount of re-generation up to that point. But it is pretty and does generally correspond with how heavy my foot is on the brake pedal.

 

[PowerboostedF150]

That’s an interesting thought, so neutral is disconcerting the electric from the engine vs putting the gears into an empty spot inside the transmission? I would think that would require a different 10r80 transmission in that case. But if it’s software controlled as others have said, I guess it’s possible. I know you can’t order the electric motor as a separate part, it’s all part of the transmission, and maybe there is more to it than tacking it onto the front.

 

[kreuss]

Earlier this year I moved from a Prius (and an F250) to a 21 PB . It's been interesting comparing the hybrid systems.

I use OBDLink to watch Engine RPM, Hybrid Battery Current, and Master Cylinder Pressure. If the engine is not running and the hybrid battery amps are negative the truck doing regen. You can watch brake pressure to see when/if the physical braking kicks in. It's wild how much the generator can slow the truck.

I just tried braking in neutral with no engine RPMs and didn't see any battery charging.. I have no idea what the brake coach is looking at.

 

[NitroDarwin]

But did you notice the chugging? My first thought when you mentioned the chugging is that my 5.0 sometimes chugges on deceleration(transmission down shifting)

 

[Lefty665]

That’s an interesting thought, so neutral is disconcerting the electric from the engine vs putting the gears into an empty spot inside the transmission? I would think that would require a different 10r80 transmission in that case. But if it’s software controlled as others have said, I guess it’s possible. I know you can’t order the electric motor as a separate part, it’s all part of the transmission, and maybe there is more to it than tacking it onto the front.

Seems like there are several different things going on with our PBs. Many of them involving the engine, HVmotor and transmission. For one, we can't get regenerative braking without the HV motor connected to the wheels. Adaptive cruise does a good job of holding downhill speed constant using regenerative braking and the HV motor. For another, when cruise is off and the throttle closed (a switch, not a physical throttle linkage) the truck will speed up downhill because the trans/HV motor is disconnected from both the wheels and the engine.

The PB can do both, either one or the other depending on switching. That's something software is good at. Remember that the shifter in PBs is a switch, not a mechanical connection. All transmission states are software driven. That includes neutral or in gear in the transmission to connect or disconnect the drive train from the wheels and either connect or disconnect from the engine at the front end via the clutch.

There is a profound amount of tech in these trucks. Ford has done an amazing job at implementing it. So good that most of the time we don't notice it. They have also stumbled over a few things that get our attention. Now if they just got a little slicker at OTA updates to patch glitches...

 

[kreuss]

I looked at little closer at the brake coach on my 21 PB. If I shift into neutral before braking I don't get a brake coach report. If I start braking and then shift to neutral I will get a report, but it feels like it's only reporting on the period while in drive.

As for chugging, I don't feel it.

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