Is Regen suddenly weaker / delayed?

[jerry33]

so they appear to have dialed down the regen from the accel pedal? Perhaps with the ibooster they have moved some of that missing regen to be triggered by the brake pedal? So the brake pedal will make electricity instead of brake dust?

It doesn't work that way. If they had moved some regen to the brake pedal you would be able to tell due to the transition between regen and no regen while the brakes pedal was pushed anytime there was a road irregularity. The feeling would be similar to losing braking for a bit.

 

[PaulusdB]

I would add the option, but not really change the behavior, just to see how many people praise the higher regen! lol

Reminds me of a friend who installed two thermostats on his central heating system. One in the hallway to actually control the system and another in the living room for his wife to use.

 

[jerry33]

Reminds me of a friend who installed two thermostats on his central heating system. One in the hallway to actually control the system and another in the living room for his wife to use.

No one laugh. My dad did something similar in his restaurant.

 

[bhzmark]

It doesn't work that way. If they had moved some regen to the brake pedal you would be able to tell due to the transition between regen and no regen while the brakes pedal was pushed anytime there was a road irregularity. The feeling would be similar to losing braking for a bit.

There must be some other thread where someone keeps suggesting "moving regen to the brake pedal" because people keep arguing against that.

I didn't suggest changing the one pedal driving. It is fine to give a driver input to signal a certain amount of regen through lifting off the accel pedal.

The suggestion is to simply tap into more regen, above what is available now, and slow car harder and faster with the front wheels and the front motor. That could be built into an increased regen from lifting off the accel. But that may be too drastic of a braking effect -- especially when coming off a cruise control without depressing the accel.

So merely for acceptable driver experience the additional regen could be triggered by the brake pedal. But that is not really important. The key is to use the additional regen capability of the front wheels which is where most of the braking takes place in normal braking anyway and make electricity instead of brake dust. The front motor and use of front wheels should make that easier.

I don't understand why someone would prefer to make brake dust instead of making electricity.

 

[Nitram]

OP here. that's certainly possible as far as weakened regen.

but, the other part of the post was about delayed regen -- a fuller braking effect kicking in a second later. i've noticed it a couple times more in the last two days, only when going 50+, but filed a Bug Report and am talking w Tesla about it. i don't think i'm imagining it. will keep you posted.

Something similar starter to occur on my S85 a few days ago.I physically felt the car suddenly increasing regen, as if the car decided to brake on its own, so I started to pay attention to it. Sometimes, but I have not been able to determine specific conditions, the regen seems to limit itself to around 30kW for a second, then quickly increases all the way down to 60kW quite brutally.
It happens with the right foot completely off the go pedal.
As I said, I physically felt it even before looking at the dial on the dashboard, and I confirm it is a new behaviour that I had never witnessed before.
I posted a short video of it here:
http://youtu.be/pfQKLTSnVcA
It happens near second 22.

 

[jerry33]

There must be some other thread where someone keeps suggesting "moving regen to the brake pedal" because people keep arguing against that.

I didn't suggest changing the one pedal driving. It is fine to give a driver input to signal a certain amount of regen through lifting off the accel pedal.

The suggestion is to simply tap into more regen, above what is available now, and slow car harder and faster with the front wheels and the front motor. That could be built into an increased regen from lifting off the accel. But that may be too drastic of a braking effect -- especially when coming off a cruise control without depressing the accel.

So merely for acceptable driver experience the additional regen could be triggered by the brake pedal. But that is not really important. The key is to use the additional regen capability of the front wheels which is where most of the braking takes place in normal braking anyway and make electricity instead of brake dust. The front motor and use of front wheels should make that easier.

I don't understand why someone would prefer to make brake dust instead of making electricity.

The thing is that the maximum allowed regen is already on the accelerator pedal. If you put some on the brake pedal, by definition you have to remove some from the accelerator pedal. Regen on the brake pedal is just a can of worms. It adds complexity to both software and hardware, you can either have a smooth braking experience by always using a fair percentage of friction braking, or you can forget smooth braking whenever you brake on an expansion joint or other rough surface. The amount of brake dust generated by the Model S is minimal compared to the amount of brake dust that would be created with smooth braking with regen on the brake pedal. I really don't see why anyone would want to ruin the braking experience like that.

 

[bhzmark]

The thing is that the maximum allowed regen is already on the accelerator pedal. If you put some on the brake pedal, by definition you have to remove some from the accelerator pedal. Regen on the brake pedal is just a can of worms. It adds complexity to both software and hardware, you can either have a smooth braking experience by always using a fair percentage of friction braking, or you can forget smooth braking whenever you brake on an expansion joint or other rough surface. The amount of brake dust generated by the Model S is minimal compared to the amount of brake dust that would be created with smooth braking with regen on the brake pedal. I really don't see why anyone would want to ruin the braking experience like that.

allow more!

embrace change and technological improvement!

I believe Bosch put the worms back in your can two years ago:
See Green Car Congress: New Bosch iBooster for improved braking control, more complete capture of braking energy in hybrids and EVs

"or hybrid and electric vehicles to achieve their intended range and fuel efficiency, they must recover as much electrical drive energy as possible when braking. Ideally, cars would be slowed down purely as a result of their electric motor converting their kinetic energy into electricity, avoiding the loss of valuable energy through braking. The Bosch iBooster recovers almost all the energy lost in typical braking operations by ensuring deceleration rates of up to 0.3 g are achieved using the electric motor alone. It thus covers all common braking maneuvers in everyday traffic.
"If the brakes to be applied harder, the iBooster generates the additional braking pressure needed in the traditional way, using the brake master cylinder. The driver does not notice this interplay of motor and brakes, as pedal feel remains absolutely normal, according to Bosch.
"Bosch has integrated a motor into the iBooster to control the degree of brake boosting via a two-stage gear unit for situation-dependent support on demand. This dispenses with the current costly, continuous process of generating a vacuum using either the internal combustion engine directly or a vacuum pump. In addition to saving fuel, it also allows more comprehensive use of fuel-saving functions that stop the engine for periods of time, such as start-stop or coasting.
"The electromechanical concept offers further advantages. Should the predictive emergency braking system detect a dangerous situation, the iBooster can build up full braking pressure autonomously in 120 milliseconds or so—three times faster than previous systems. In emergency situations, therefore, the iBooster can brake the vehicle faster than a driver using a conventional braking system.
"The iBooster can also take on the Adaptive Cruise Control’s (ACC’s) job of gently bringing the vehicle to a standstill, and do so comfortably and noiselessly. This is particularly compelling for quiet e-vehicles, since ambient sounds are much more noticeable in their interior.
"The ability to define characteristic braking curves gives developers the freedom to determine pedal feel and adapt it to the customer's brand-specific wishes. If the vehicle also offers driving modes such as sport, comfort, or economy, the brakes can be made to react more softly or more aggressively as appropriate. Situation-dependent support is also possible, for instance during emergency braking.
"With a freely programmable braking performance curve, identical Bosch iBoosters can be installed in different variants of a vehicle model and still offer tailored characteristics. Programming is quick and easy at the end of the production line, and it is easy to vary the installation to suit right-hand-drive or left-hand-drive models, according to Bosch.
"The booster unit itself is purely electromechanical, without brake fluid, which means it can be rotated flexibly about the longitudinal axis. Consideration has also been given to the future of car driving: in combination with Bosch ESP, the system offers the level of braking-system redundancy that is needed for safety reasons in automated self-driving cars.

 

[joetz]

I'm surprised after 5 pages of reading no one has suggested what is, to me, the obvious answer. Think about the monster amount of load getting on the throttle and abruptly off the throttle causes? I have seen what can happen to gas drivetrains subjected to power in only one direction (broken gear teeth, stripped splines, twisted shafts, damaged CV joints), without abruptly reversing the loads. Imagine what kinds of forces regenerative braking puts on the drivetrain? I'm sure easing into regen is going to save tesla a lot in warranty costs.

 

[joetz]

I just wanted to add that this is nothing new and other manufacturers have dulled the response to pedal inputs to prolong the life of drivetrain componants. GM calls their lazy throttle tip in "torque management"

 

[AmpedRealtor]

Reminds me of a friend who installed two thermostats on his central heating system. One in the hallway to actually control the system and another in the living room for his wife to use.

ROTFL!