Hybrid "Hump Feeling" while Breaking

[solidbrix]

So I've had my LC for just over 2 weeks now. Put on 1,400 miles () and have noticed inconsistent breaking. What I'm specifically talking about it is if I'm slowing down from 45-50mph to 0 for a stoplight, depending on how I'm breaking, you'll feel a hump or like your skipping over something as the LC comes to a complete stop. The actual breaks are working just fine, but it feels like it's coming from the transmission. Now I also noticed this last month on a different 1958 LC that I test drove & didn't think much of it at the time (thought maybe its brand new and just needs to be broken in).

For context, this is my first hybrid vehicle I've ever owned. I'm coming from a 4Runner. I've also driven some of my families Teslas around so I know what regenerative breaking feels like.

My assumption is that these humps, jerky jolts during breaking is the electric/hybrid components either using regenerative breaking for charging the battery (maybe its switching in/out) or there's still energy from the electric motor trying to whine down? It doesn't happen every time, it's a strange feeling. I have the LC in normal drive mode.

 

[chris_in_phx]

I think ive felt this too

 

[Werlyb23]

I’m still getting used to the breaks after a month in lol

 

[jbe2289]

My understanding is that it regenerates and hence breaks by turning the electric motor. It definitely has pronounced down shifts too that I think are part of this regeneration process. I also believe it is inconsistent and depends on the computers variables, such as how hard the breaks are pressed, state of charge, battery temperature, and perhaps others.

 

[Nuke]

Not sure if it has the ability to turn the electric motor backwards, as it couples to the direct output of the engine, but the electronics can switch modes between battery power to assist, and conversely turning the motor into a generator to charge the battery.

 

[daspyknows]

I have noticed that too. In regards to the regenerative braking and gas mileage, going downhill sure seems to boost the mileage versus climbing. I drove from Los Angeles to Oakland today and reset the mileage. Going through LA traffic in Eco mode the first 70 miles I was at 18 MPG. Going up to the pass my MPG had dropped to 15.5 MPG and driving down I was up to 19.5 MPG. Trip ended at 18.7 MPH at 80 MPH. Not great but I know mileage better driving slower.

 

[xeontis]

In our electric car we hardly use the brakes because the regenerative braking is so good. I think a lot of people think that regenerative braking has something to do with the brakes but it does not. The electric motor is what you are feeling, so rather than putting electricity to the motor which will create torque and rpm instead it's being used as a generator so the resistance in the electric motor is slowing you down (think engine braking) it's also generating electricity and charging the battery (no energy is free) it's trading vehicle speed for electricity. The braking in this does feel odd, it's adding "braking" via the electric motor resistance while you are slowing down. I suspect, because it feels this way is that regen stops or diminishes while braking and you loose that extra braking (from the electric motor) and have to press the brake pedal more to compensate. I'll bet Toyota will fix it in a software update or at least smooth out the transition.

 

[Tripod1404]

Not sure if it has the ability to turn the electric motor backwards, as it couples to the direct output of the engine, but the electronics can switch modes between battery power to assist, and conversely turning the motor into a generator to charge the battery.

Yep, to put very simply. And electric motor is is a coil that sits between magnets. If you pass an electric current through this coil, electromagnetic field forms, which reacts with the magnets and causes the coil to spin. In the opposite way, if you spin the coil, magnets will induce a current, which can be used ti charge a battery.

Sp the motor doesn’t need to spin in reverse, when you break or coast, momentum of the car spins the electric motor which acts as a generator.

 

[Nuke]

Yep, to put very simply. And electric motor is is a coil that sits between magnets. If you pass an electric current through this coil, electromagnetic field forms, which reacts with the magnets and causes the coil to spin. In the opposite way, if you spin the coil, magnets will induce a current, which can be used ti charge a battery.

Sp the motor doesn’t need to spin in reverse, when you break or coast, momentum of the car spins the electric motor which acts as a generator.

Is not the coil (stator) stationary, and the permanent magnets (rotor) moving? I don't believe the motor/generator uses a commutator.

 

[Tripod1404]

Is not the coil (stator) stationary, and the permanent magnets (rotor) moving? I don't believe the motor/generator uses a commutator.

Yes, I gave the example in the oposite way. Basically one side is stationary and the other side rotates.

 

[Tripod1404]

In our electric car we hardly use the brakes because the regenerative braking is so good. I think a lot of people think that regenerative braking has something to do with the brakes but it does not. The electric motor is what you are feeling, so rather than putting electricity to the motor which will create torque and rpm instead it's being used as a generator so the resistance in the electric motor is slowing you down (think engine braking) it's also generating electricity and charging the battery (no energy is free) it's trading vehicle speed for electricity. The braking in this does feel odd, it's adding "braking" via the electric motor resistance while you are slowing down. I suspect, because it feels this way is that regen stops or diminishes while braking and you loose that extra braking (from the electric motor) and have to press the brake pedal more to compensate. I'll bet Toyota will fix it in a software update or at least smooth out the transition.

A difference between an EV and a hybrid is that in most EVs “default” regenerative braking is stronger . This means that as soon as you lift you feet of the throttle, battery draws large amounts of current from the electric motor an slows do car down, allowing one pedal driving. In hybrids regenerative is controlled by the driver. When we press the brake, hybrid controller increase the current drawn by the battery and slow the car down. So a significant amount of breaking power is generated by the electric motor when we press the break. This is why break on hybrid cars last longer.

 

[hosewater2]

I’m still getting used to the regen “engine braking,” it seems rough because as you coast down from 45 MPHish you get lots of regen, then it abruptly stops regenerating when you get down to about 10 MPH, and you have to take over braking from there or else it freaks that you’re going to hit the car in front of you. I wish it would just regen all the way to a stop like a Tesla. If you actually want to just coast, you have to have foot on accelerator very lightly. Getting used to it, but not sure this will be acceptable to the mass market 4R crowd next year, it’s just so different.

 

[deftkillerstu]

I have felt this as well too and it’s so inconsistent that I haven’t figured out what causes it. Like someone said earlier, I hope Toyota puts out a software update to fix it.

 

[jv25010]

So I've had my LC for just over 2 weeks now. Put on 1,400 miles () and have noticed inconsistent breaking. What I'm specifically talking about it is if I'm slowing down from 45-50mph to 0 for a stoplight, depending on how I'm breaking, you'll feel a hump or like your skipping over something as the LC comes to a complete stop. The actual breaks are working just fine, but it feels like it's coming from the transmission. Now I also noticed this last month on a different 1958 LC that I test drove & didn't think much of it at the time (thought maybe its brand new and just needs to be broken in).

For context, this is my first hybrid vehicle I've ever owned. I'm coming from a 4Runner. I've also driven some of my families Teslas around so I know what regenerative breaking feels like.

My assumption is that these humps, jerky jolts during breaking is the electric/hybrid components either using regenerative breaking for charging the battery (maybe its switching in/out) or there's still energy from the electric motor trying to whine down? It doesn't happen every time, it's a strange feeling. I have the LC in normal drive mode.

My 22 hybrid volvo xc60 does exactly what you describe. I think its the nature of hybrids.

 

[neilwill]

I’m not sure if this may help, but there are several settings for the brakes that you can choose through the MID console. I just discovered it in my getting to know the car and haven’t really read up on it yet.

 

[Captain Trips]

I’m not sure if this may help, but there are several settings for the brakes that you can choose through the MID console. I just discovered it in my getting to know the car and haven’t really read up on it yet.

The settings for brakes in the mid console are for the tow brake controller.

 

[ironswifty]

This exact issue bugs the crap out of me. I had a 23' Camry Hybrid that I drove 20K miles and did not have this issue at all. I notice it does not happen when I have PCS turned off but I have only driven the vehicle 200 miles.

I am trying to go to toyota so they can default my PCS to OFF and if I want it on I can go and turn it on in the settings.

 

[neilwill]

Close to 500 miles in, I’m not experiencing this issue at all. The brakes seem pretty normal to me and work very well.

 

[Dr. M]

I have owned a fully electric Hyundai Kona as well as a Tesla Model Y. The definitely brake harder and faster with regen that my new LC FE. But, I have not noticed any meaningful differences between the LC and our Hyundai Tucson PHEV in terms of braking. I am a happy camper, thus far, with 500 miles on the LC.

 

[LCNorth]

I just call this “hybridy-stuff” and carry on enjoying my LC.

But I’ve driven a lot of quirky vehicles over the years.