[Homer Simpson]

Rarely, while braking, and the car is approaching ~ 5mph to ~ 10mph speed range, I get a sudden brief acceleration, less than 1 second, but definitely acceleration. It is unnerving.
The first few times I thought my foot had slipped off the brake and hit the accelerator.
After more experience with the issue, this is definitely not the cause.
It happens maybe once every other trip, usually at low speed, when approaching a stop light for instance.
Some may call this unexpected 'lurching' during braking.

It may be related to the regenerative braking system. However, I would expect a loss of braking power, not acceleration, if this was the case.
Yes it is actual acceleration, positive dV/dt, not loss of braking that I feel.

I found some folks experienced similar issues but most seemed to feel it was a loss of braking

Brake issues anyone?

Granted those are normal new rotor condition. Either way its easy to rule out rust, just look.

www.pacificaforums.com

It is unlikely that I am going to take it in to dealer, as it is an intermittent issue and likely no problems will be found.

Anyone experience similar?

Thanks

 

[PacDave]

Rarely, while braking, and the car is approaching ~ 5mph to ~ 10mph speed range, I get a sudden brief acceleration, less than 1 second, but definitely acceleration. It is unnerving.
The first few times I thought my foot had slipped off the brake and hit the accelerator.
After more experience with the issue, this is definitely not the cause.
It happens maybe once every other trip, usually at low speed, when approaching a stop light for instance.
Some may call this unexpected 'lurching' during braking.

It may be related to the regenerative braking system. However, I would expect a loss of braking power, not acceleration, if this was the case.
Yes it is actual acceleration, positive dV/dt, not loss of braking that I feel.

I found some folks experienced similar issues but most seemed to feel it was a loss of braking

Brake issues anyone?

Granted those are normal new rotor condition. Either way its easy to rule out rust, just look.

www.pacificaforums.com

It is unlikely that I am going to take it in to dealer, as it is an intermittent issue and likely no problems will be found.

Anyone experience similar?

Thanks

Just curious how you came up with the idea that it’s not loss of braking but definitely acceleration. How can you tell the difference? Remember that acceleration is an increase in rate of speed and also remember that most, if not all, braking at that speed is done by regeneration instead of friction braking. If, all of a sudden, there was either no load for the regenerative system to drain into or if the regeneration just suddenly stopped, you would feel as if there were a surge because you were decelerating and then suddenly stopped decelerating. But acceleration means something like you were going 5mph and now you’re going 6mph.

I have felt something like this before but I attributed it to an inaccurate transition from regenerative braking to friction braking. I really don’t notice it much anymore. if it is happening I have grown accustomed to it.

 

[Homer Simpson]

Just curious how you came up with the idea that it’s not loss of braking but definitely acceleration. How can you tell the difference?

d

A fair question. Put simply I am relying on my senses to differentiate the type of movement I am feeling,and also I'm pretty sure the van moves faster, but very briefly.
But, you are right, this is not at all scientifically valid.

I would need to get some sort of instrument to continuously monitor braking pedal pressure input, speed, torque to the wheels, etc., to get a reproducible data.
I have no interest in doing this, but maybe someone on the forums does....

 

[ScorpyMjolnir]

Homey,

I had a very few instances of this with my 2017 back when I first got it. I was able to narrow it down to the way I used my brakes as I approached a stop. The van would feel like it lurched forward as I pressed the brake and was almost at a complete stop. It appeared to be related to the transition between mechanical to regenerative braking. I started using a slightly firmer foot on the brake and it went away. My wife never experienced it, and we drive about 50/50. Try a slightly firmer push on the pedal and see if it goes away.

 

[CANADAHYBRIDGUY]

It’s so funny how people when prior , during, after the purchase assume this van , or any electric hybrid , will drive the same as a ice version . The question I ask is “ did people Not drive this thing prior to purchase “. The sheer complexity of running electric and battery electric with regenerative braking is pretty complex . You def have have to adapt a different driving style, process and mind set when driving electric . There definitely is a transition period for learning the vehicles dynamics, characteristics that comes with ownership .

 

[Homer Simpson]

Thanks Scorpio....

 

[ScorpyMjolnir]

he question I ask is “ did people Not drive this thing prior to purchase “.

Nope, I ordered mine months before it began production. Early adopter.

 

[PacDave]

Homey,

I had a very few instances of this with my 2017 back when I first got it. I was able to narrow it down to the way I used my brakes as I approached a stop. The van would feel like it lurched forward as I pressed the brake and was almost at a complete stop. It appeared to be related to the transition between mechanical to regenerative braking. I started using a slightly firmer foot on the brake and it went away. My wife never experienced it, and we drive about 50/50. Try a slightly firmer push on the pedal and see if it goes away.

Yeah, my first guess would that this is just merely a slight decrease in braking effectiveness on the part of the regenerative system. For some reason the regenerative braking system cuts out a little early before the friction brakes have really taken hold.

 

[Copac]

It’s so funny how people when prior , during, after the purchase assume this van , or any electric hybrid , will drive the same as a ice version . The question I ask is “ did people Not drive this thing prior to purchase “. The sheer complexity of running electric and battery electric with regenerative braking is pretty complex . You def have have to adapt a different driving style, process and mind set when driving electric . There definitely is a transition period for learning the vehicles dynamics, characteristics that comes with ownership .

Yes, I did about a 2 hour test drive.I wanted to see how the difference is between the gas, and electric. It was the seemless transition between the gas and electric, and the electronic CV transmission that sold me. as far as the driver, I see no reason to drive any differently then a full gas version. The Engineer in me just did not like the 17 pac going through 3 gears before I made it through the intersection. I am not going to get into a discussion of the transmissions here, So please do not attack me on how good the ICE tranny is. I think this place would be better if we would try to answer the members question, rather then tell them they do not know anything.

Rarely, while braking, and the car is approaching ~ 5mph to ~ 10mph speed range, I get a sudden brief acceleration, less than 1 second, but definitely acceleration. It is unnerving.
The first few times I thought my foot had slipped off the brake and hit the accelerator.
After more experience with the issue, this is definitely not the cause.
It happens maybe once every other trip, usually at low speed, when approaching a stop light for instance.
Some may call this unexpected 'lurching' during braking.


Anyone experience similar?

Thanks

Sorry, I hate posting to a thread, and not answer the OP's question, But I had to respond to respond to HBG's post. I have not driven since you posted this, but tomorrow when I do the weekly shopping trip, I will try to see if I can feel what you do.

 

[AUManVan]

I can totally back you up and have this as a safety complaint with Chrysler at the moment. I've experienced it a hand full of times but from a higher speed slow down. I will relate that it feels like acceleration not a loss in braking power. When it happens, my brain goes into panic mode and it takes your breath away until they grab back. My transmission was replaced recently, 58 days in service, and thought it would fix it along with the main issue. Sadly No. I can't figure out a way to replicate it though.

 

[Homer Simpson]

Yesterday I was actually fully stopped in line at a stop light. My foot was lightly on the brake, no incline, and after coming to a complete stop for several seconds, with my foot still lightly depressing the brake, the van started to move forward. I tried looking at the instrument cluster to see if the acceleration meter was in the green, but had to quickly pay attention and depress the brakes more firmly to stop.
So yeah, it's unintentional acceleration, not loss of braking.

Still not going to take it in, because I know the results of testing will be 'no problem found'.

 

[r2rm]

Ok, I ordered my 2017 Hybrid in November of 2016 to take ownership around April or May of 2017. There was a recall on the car and none were released until around September. I live on the south west coast so the first dealers here saw their Hybrids in October of 2017. I was hopping mad, I now wanted a 2018 for their screw up.
Let me get to the point of this discussion. The acceleration issue I have felt is when I am using the Cruise Control. Now I use the Adaptive Cruise Control more than the regular Cruise Control because it self adjusts to the speed of traffic. I haven’t been driving much lately but I recall my wife upset with the way I drive. And I remember in those instances the vehicle unexpectedly accelerated making me take control of the vehicle in a heartbeat.
You bet it was a bit scary. I just had to remember to be alert when using the Adaptive Cruise Control because it will brake unexpectedly and it will accelerate unexpectedly around chaotic traffic.
But the nice thing about the ACC mentioned here is that it follows the traffic really nice, and it stops & go’s really nice.

 

[Oliver]

Homer,

Last month I moved to the hills of Northern California and started getting the jolt you described. For me, it always occurs when I’m trying to milk the regenerative braking system by slowly stopping. It’s much worse going downhill— almost scary, missing the stop sign a few times. I agree with Scorpymjolnir and PacDave. It has to do with the transition to conventional brakes. Stopping more abruptly takes care of it for me. Hope it’s close to the same thing you’re experiencing.

 

[craig]

Yes, I did about a 2 hour test drive.I wanted to see how the difference is between the gas, and electric. It was the seemless transition between the gas and electric, and the electronic CV transmission that sold me. as far as the driver, I see no reason to drive any differently then a full gas version. The Engineer in me just did not like the 17 pac going through 3 gears before I made it through the intersection. I am not going to get into a discussion of the transmissions here, So please do not attack me on how good the ICE tranny is. I think this place would be better if we would try to answer the members question, rather then tell them they do not know anything.

Sorry, I hate posting to a thread, and not answer the OP's question, But I had to respond to respond to HBG's post. I have not driven since you posted this, but tomorrow when I do the weekly shopping trip, I will try to see if I can feel what you do.

HBG needs to show what he believes is his superior intellect. It is actually the only reason that he posts anything here. Perhaps he's short.

 

[Copac]

HBG needs to show what he believes is his superior intellect. It is actually the only reason that he posts anything here. Perhaps he's short.

Too bad some people can not tell the difference between arrogance, and intellect.

Rarely, while braking, and the car is approaching ~ 5mph to ~ 10mph speed range, I get a sudden brief acceleration, less than 1 second, but definitely acceleration. It is unnerving.

I just tried all morning to get a similar reaction, but could not. I was originally thinking it could be when the brakes switch from regen, to regular brakes, But realized that was a stupid idea, there is no need for the regen brakes to stop. And you can watch the left power/ charge gauge, it shows charging almost all the way to stopped.

Next time you are driving, try to watch the power/ charge gauge, and see if it does anything when you noticed the acceleration sensation.

 

[PacDave]

Too bad some people can not tell the difference between arrogance, and intellect.

I just tried all morning to get a similar reaction, but could not. I was originally thinking it could be when the brakes switch from regen, to regular brakes, But realized that was a stupid idea, there is no need for the regen brakes to stop. And you can watch the left power/ charge gauge, it shows charging almost all the way to stopped.

Next time you are driving, try to watch the power/ charge gauge, and see if it does anything when you noticed the acceleration sensation.

There is definitely a point at which the regen braking becomes effectively nil and it’s before you come to a full stop. When you’re pushing on the brake pedal the car must translate that request to slow down and select the right method and/or combination of methods to effectuate the stop. The attempt is to use the regen method primarily and as much as possible. But if the driver calls for more braking than the regen system can achieve it must modulate in the friction brakes. I believe there is a point as the vehicle speed is getting slower and slower where the regenerative effect no longer has a linear relation to the vehicle speed and drops off rather quickly. This is where the how much/when to apply the friction brakes comes in. I also believe that in a certain range of deceleration the application of friction brakes is just a little bit late. As the regen effect drops off rather quickly providing very little braking the friction braking is either delayed or not quite aggressive enough to maintain the deceleration called for by the position of the brake pedal. This causes the feeling that the car is accelerating but in reality it’s just not decelerating as fast as it was when the regen was aggressively slowing the vehicle.

Just my deduction. Could be wrong but it seems like the most logical thing.

Also, a quote from a Wiki page on regen braking:

Practical regenerative braking
Regenerative braking is not by itself sufficient as the sole means of safely bringing a vehicle to a standstill, or slowing it as required, so it must be used in conjunction with another braking system such as friction-based braking.

• The regenerative braking effect drops off at lower speeds, and cannot bring a vehicle to a complete halt reasonably quickly with current technology...

 

[Copac]

I Get all that. If it is because of a space between the regen braking, and the hydraulic brakes taking over, I suspect Homer will see that the charge needle raises back to zero at the point he feels the acceleration.

I wish I knew how Chrysler keeps the friction brakes from engaging to allow the regen to work first. I'm suspecting that this is something we may all feel at a future time. Some may already feel it, just that it started so slowly they never noticed it. My Pac just rolled over the 1K miles today. I have a few ideas, but not knowing how the two systems work together, I may be off base. I wish I had a service manual, but not enough to spend a hundred or two yet. My wallet is still hurting from the slimming the state took, when I went for registration, My gustimate was way off.

 

[craig]

I Get all that. If it is because of a space between the regen braking, and the hydraulic brakes taking over, I suspect Homer will see that the charge needle raises back to zero at the point he feels the acceleration.

I wish I knew how Chrysler keeps the friction brakes from engaging to allow the regen to work first. I'm suspecting that this is something we may all feel at a future time. Some may already feel it, just that it started so slowly they never noticed it. My Pac just rolled over the 1K miles today. I have a few ideas, but not knowing how the two systems work together, I may be off base. I wish I had a service manual, but not enough to spend a hundred or two yet. My wallet is still hurting from the slimming the state took, when I went for registration, My gustimate was way off.

My 2020 Touring L 35th Edition Hybrid was $640 to register in CA. Was yours that bad or worse?

 

[Copac]

My 2020 Touring L 35th Edition Hybrid was $640 to register in CA. Was yours that bad or worse?

$1,051.08. The 17 Pac I traded in, was something around $450. I was guesstimating about $800 or so. As bad as a cell phone bill with all the added BS fees. Except for the $7.20 title fee, I will pay about the same next year.

 

[craig]

WOW! That's a tough pill to swallow. I always thought/guessed that CA had the highest registration costs, but wow! I had 7.75% sales tax on top of the $640. Does your "Specific Ownership Tax" replace sales tax?