[JayjayJay]

I’m pretty sure the answer is no but figured I’d ask to see if anyone had some insight.

Do any Toyotas have the ability to change the regen brake settings? I think Hyundai hybrids had paddles on the steering wheel to change it for a bit.
I wouldn’t want to one pedal drive like a Tesla but it would be cool to be able to play around with it.

 

[BostonPilot]

I’m pretty sure the answer is no but figured I’d ask to see if anyone had some insight.

Do any Toyotas have the ability to change the regen brake settings? I think Hyundai hybrids had paddles on the steering wheel to change it for a bit.
I wouldn’t want to one pedal drive like a Tesla but it would be cool to be able to play around with it.

Nope, it can’t be changed.

 

[Chubbysumo]

Nope, it can’t be changed.

this isn't true, to some degree, you can change how it acts with the "drive" modes. Eco mode means that the regen is really heavy on pedal lift off, but its not down to 1 pedal driving. "normal" mode is just like you would expect, the regen really doesn't kick in until you start braking, but its there on pedal lift off some. in "sport", the regen braking isn't on at all until you start braking, and then it hits hard.

 

[JayjayJay]

Interesting. I didn’t realize the drive mode would affect the brakes. I gotta test it out even though I hardly use eco mode nowadays because of how it affects the AC.

 

[BostonPilot]

Interesting. I didn’t realize the drive mode would affect the brakes. I gotta test it out even though I hardly use eco mode nowadays because of how it affects the AC.

You didn’t realize it, because it doesn’t.

 

[BostonPilot]

this isn't true, to some degree, you can change how it acts with the "drive" modes. Eco mode means that the regen is really heavy on pedal lift off, but its not down to 1 pedal driving. "normal" mode is just like you would expect, the regen really doesn't kick in until you start braking, but its there on pedal lift off some. in "sport", the regen braking isn't on at all until you start braking, and then it hits hard.

Cool story, but literally everything you just said, is wrong.

 

[Chubbysumo]

Cool story, but literally everything you just said, is wrong.

really? I drive my van 8 hours a day, 5 days a week. as of friday, which was about 1 year and 3 months of ownership, it has 133000 miles. yes, it changes the regen profile, and it changes the accelerator pedal response too. doesn't change the steering assist strength tho.

I have several long hills to test it on. when in ECO mode, the van will maintain speed going down all but the steepest grades. in normal, I have to hit the brake pedal to maintain speed going down a hill on even shallow grades, and in sport, there is hardly any regen hit at all once you are off the accelerator pedal, but as soon as you hit the brake pedal it hits hard in a very short stroke of the brake pedal in comparison to the other 2 modes.

if you have some info as to why you claim it doesn't, then im all eyes. otherwise, I can just record some videos of the differences for you to see next weekend.

 

[Dimitrij]

really? I drive my van 8 hours a day, 5 days a week. as of friday, which was about 1 year and 3 months of ownership, it has 133000 miles. yes, it changes the regen profile, and it changes the accelerator pedal response too. doesn't change the steering assist strength tho.

I have several long hills to test it on. when in ECO mode, the van will maintain speed going down all but the steepest grades. in normal, I have to hit the brake pedal to maintain speed going down a hill on even shallow grades, and in sport, there is hardly any regen hit at all once you are off the accelerator pedal, but as soon as you hit the brake pedal it hits hard in a very short stroke of the brake pedal in comparison to the other 2 modes.

if you have some info as to why you claim it doesn't, then im all eyes. otherwise, I can just record some videos of the differences for you to see next weekend.

133K miles in 15 months? Wow, I thought I was putting a lot of miles on, hitting 50K at less than 17 mts (3K mi/mo).

What you are describing, I assume it's with the ACC on, correct?

 

[Vanfam12345]

What you are describing, I assume it's with the ACC on, correct?

Not necessarily. It seems even when manually controlling the accelerator pedal, the different drive modes will alter how quickly regen braking begins / how it behaves overall. In Eco mode, the system will being regen braking the moment your foot leaves the accelerator pedal. In normal, it is slower to engage. In sport, it only engages when physically pressing the brake pedal. None of these are dependent on the ACC, but I believe the behavior of that changes also in terms of acceleration curves and throttle inputs based on speed and surroundings (based on drive mode selected).

 

[bikermiker]

Cool story, but literally everything you just said, is wrong.

Cool story. Care to elaborate?

 

[Chubbysumo]

Not necessarily. It seems even when manually controlling the accelerator pedal, the different drive modes will alter how quickly regen braking begins / how it behaves overall. In Eco mode, the system will being regen braking the moment your foot leaves the accelerator pedal. In normal, it is slower to engage. In sport, it only engages when physically pressing the brake pedal. None of these are dependent on the ACC, but I believe the behavior of that changes also in terms of acceleration curves and throttle inputs based on speed and surroundings (based on drive mode selected).

This pretty much nails it, and has been my experience in testing. This is without using the adaptive cruise control, the drive mode does more than simply put a light on the dash, there are more subtle changes that people may not realize without being told. It is why a lot of people stick it in eco mode and then complain that the air conditioning or heating doesn't blow very hard. while my van doesn't leave eco mode that often, I did test the different Drive modes to see what the differences were. None of the modes affected the steering assistance to any degree that could notice, though with electric power steering other models in the Toyota lineup have proven this to be a possibility.

One thing I really haven't been able to test is if the traction battery is fully charged, and you are in sport mode, if it will use the electric motors as well as the gas Motor at the same time to Aid in a short burst of high power output acceleration. I know in the RAV4 prime, this behavior is present, and it uses a similar hybrid system to what the Sienna has. I mean if you added up, that could give you short bursts of acceleration with 420 horsepower, and 450 foot pounds of torque in the awd trim. Now I'm going to have to find a way to test this damn it.

 

[jseyfert3]

One thing I really haven't been able to test is if the traction battery is fully charged, and you are in sport mode, if it will use the electric motors as well as the gas Motor at the same time to Aid in a short burst of high power output acceleration. I know in the RAV4 prime, this behavior is present, and it uses a similar hybrid system to what the Sienna has. I mean if you added up, that could give you short bursts of acceleration with 420 horsepower, and 450 foot pounds of torque in the awd trim. Now I'm going to have to find a way to test this damn it.

How would you test this? Also I'm not sure you can just add this up. The RAV4 hybrid has a 176 HP engine, alone with a 118 HP front motor and 54 HP rear motor. But it doesn't net you 348 HP, the combined net HP is only 219. More than the engine? Sure. As much as you'd expect? Not really.

 

[Chubbysumo]

How would you test this? Also I'm not sure you can just add this up. The RAV4 hybrid has a 176 HP engine, alone with a 118 HP front motor and 54 HP rear motor. But it doesn't net you 348 HP, the combined net HP is only 219. More than the engine? Sure. As much as you'd expect? Not really.

Im talking about the prime, which has a much larger battery. im sure those HP/TQ numbers are not burst numbers, so the combined output is the mix of both the engine and the electric system at once. BUT, hear me out, the prime has the exact same hybrid drive system as the regular hybrid, just a smaller battery, thus a lower electric and combined output. the combined output of the prime version is about 83hp higher, and its able to use both the full capacity of the electric motors, as well as the gas engine for short bursts in short acceleration tests. I just wonder if the same programming is in the regular hybrids, but would really only work when the traction battery is full, and really for a super short time.

im gonna have to figure out a way to test it now, its not, just need a short stretch of road that is at the bottom of a hill. test the 0 to 30 with my OBD2 with the traction battery empty, and then go up the hill, come down, charge the battery, and test it with the battery full. can repeat as many times as I need.

 

[jseyfert3]

Im talking about the prime, which has a much larger battery. im sure those HP/TQ numbers are not burst numbers, so the combined output is the mix of both the engine and the electric system at once. BUT, hear me out, the prime has the exact same hybrid drive system as the regular hybrid, just a smaller battery, thus a lower electric and combined output. the combined output of the prime version is about 83hp higher, and its able to use both the full capacity of the electric motors, as well as the gas engine for short bursts in short acceleration tests. I just wonder if the same programming is in the regular hybrids, but would really only work when the traction battery is full, and really for a super short time.

im gonna have to figure out a way to test it now, its not, just need a short stretch of road that is at the bottom of a hill. test the 0 to 30 with my OBD2 with the traction battery empty, and then go up the hill, come down, charge the battery, and test it with the battery full. can repeat as many times as I need.

Ah, good point. Forgot about that. It appears there’s only a 1.6 kWh NiMH battery in the regular RAV4. At 172 HP electric, that requires 129 kW not counting inefficiencies of the drive and motor! So the battery could only run that for a grand total of…45 seconds 😂

That’s not the only issue though. NiMH can only discharge at maybe 20 C, at least continuously, which would be 32 kW, or 43 HP (again not counting inefficiencies). That would get you 3 minutes though.

The RAV4 prime has an 18.1 kWh lithium pack. Usually good to 30C, so you’d be able to do 540 kW from the battery in theory. Or 720 HP. From a practical standpoint there’s no way they designed the wiring to handle that. But yes, the battery wouldn’t be the limit there.

It’s also unclear if the front motor HP rating is just MG2 or if they combined MG1 and MG2 to get better specs to advertise. I am still a bit fuzzy on how the hybrid synergy drive works, but I think you can’t use both motors and the engine to full power, since to get the gear ratio correct for the engine they run one of the two MGs as a motor, and one as a generator, as I understand.

 

[Chubbysumo]

It’s also unclear if the front motor HP rating is just MG2 or if they combined MG1 and MG2 to get better specs to advertise. I am still a bit fuzzy on how the hybrid synergy drive works, but I think you can’t use both motors and the engine to full power, since to get the gear ratio correct for the engine they run one of the two MGs as a motor, and one as a generator, as I understand.

Weberauto YT channel has a great breakdown of the toyota hybrid system.

toyota has been using the same design since the first gen prius. The video is the P710. The P810 is what is in the new sienna, rav4 prime, and hybrid highlanders. Its exactly the same but a larger MG2. MG2 is directly driving the vehicle and can move the vehicle independent of MG1(which is coupled to the motor for the "ecvt" part). Yes, if you had enough power in the battery, you could run both MG2 at full output, and also use the ICE with MG1 to also assist in pushing the vehicle forward. The reason that the rav4 prime has more total combined power is because they are driving MG2 with the battery, and also using all the 180hp the motor has. I just wonder if they allowed the sienna's battery to burst discharge that hard for a short duration, think like 20 seconds or less, just for quick acceleration for like passing. gonna have to test it.

 

[jseyfert3]

MG2 is directly driving the vehicle and can move the vehicle independent of MG1(which is coupled to the motor for the "ecvt" part).

Not entirely, is my understanding. I believe if the engine is not spinning, and you tried to use MG2 to drive the vehicle without applying a load to MG1, then MG1 would just freewheel and the vehicle wouldn’t move. It’s a very clever system, but I want to build a model of it so I can more fully understand it.

I’ll try to watch that video later. I’ve watched a couple videos and read several articles trying to fully wrap my head around how it works. My current understanding, which is probably somewhat faulty, is imagining two differentials tied together with the engine, MG1, MG2, and the wheels taking up the other inputs/outputs of the differentials. I think this mental model is reasonably close to, but not entirely accurate.

 

[Vanfam12345]

I’ll try to watch that video later. I’ve watched a couple videos and read several articles trying to fully wrap my head around how it works.

If you’re at all interested in engineering and figuring out how things work, then the video sumo linked above is outstanding (and applies equally to the Sienna which functions exactly the same way, just larger).

 

[catfish93]

I’m pretty sure the answer is no but figured I’d ask to see if anyone had some insight.

Do any Toyotas have the ability to change the regen brake settings? I think Hyundai hybrids had paddles on the steering wheel to change it for a bit.
I wouldn’t want to one pedal drive like a Tesla but it would be cool to be able to play around with it.

No, haha. You need to understand the customer base that Toyota markets to. The average consumer is NOT a car enthusiast like us. They see a car like a washing machine: An appliance you buy because you need it for a specific purpose. (In this case, transportation. Toyota - Let's go places) They want simplicity. They want uniformity. They want familiarity.

Historically, Toyota has always been extremely conservative. They don't rock the boat with new untested features and they don't want people to complain about the car acting differently all of a sudden because they accidentally bumped a paddle which they had no idea what it did.

20 years ago, this hybrid thing was a quantum leap and a HUGE risk for Toyota. They built the Prius, I think deliberately, in such a way that would scare off people who weren't entirely committed to trying out something new. Turns out it was a huge hit, and a lot of people wanted a hybrid car but wouldn't be caught dead at the wheel of a Prius, so along came the Camry hybrid. But now that every model is being hybridized, they must make a concerted effort to make the hybrid versions drive very similarly to the traditional ICE only versions. Lest potential customers deem the car too scary and futuristic and go buy an Odyssey, which is more familiar to them.

Still, the engineers throw enthusiasts like us a "bone" here and there, lest we think their cars are too boring and buy a Honda for more excitement. They give us drive modes, which change throttle response AND steering response (Yes! Engage sport mode while negotiating a cloverleaf exit. The simulated feedback does get heavier.) The Prius has a dedicated "B" mode for additional regenerative braking, and the Sienna actually has some version of it too. While coasting at 25MPH with EV indicator on, push your shifter from "D" into manual mode. You'll feel extra regen initially down to about 20MPH. Now, drop a gear (it defaults to 4th). At 17MPH, drop it into 2nd. At 10MPH, 1st. Much faster than those speeds and you'll force the engine on. When stopping, hold the shifter up for 2 seconds or so, it'll automatically select "6th gear" which accelerates and behaves exactly like D. When slowing down in 6th, you can start dropping "gears" at 30MPH without forcing the engine on. SIDE NOTE: This is a CVT transmission. It does not have gears. These are simulated ratios that can provide a bit more regen/a bit more acceleration at low speeds. Though if you wanted acceleration from a Gen 4 Sienna, you'd need to push it off a cliff.

 

[Jetstreamblue]

Ah, good point. Forgot about that. It appears there’s only a 1.6 kWh NiMH battery in the regular RAV4. At 172 HP electric, that requires 129 kW not counting inefficiencies of the drive and motor! So the battery could only run that for a grand total of…45 seconds 😂

That’s not the only issue though. NiMH can only discharge at maybe 20 C, at least continuously, which would be 32 kW, or 43 HP (again not counting inefficiencies). That would get you 3 minutes though.

The RAV4 prime has an 18.1 kWh lithium pack. Usually good to 30C, so you’d be able to do 540 kW from the battery in theory. Or 720 HP. From a practical standpoint there’s no way they designed the wiring to handle that. But yes, the battery wouldn’t be the limit there.

It’s also unclear if the front motor HP rating is just MG2 or if they combined MG1 and MG2 to get better specs to advertise. I am still a bit fuzzy on how the hybrid synergy drive works, but I think you can’t use both motors and the engine to full power, since to get the gear ratio correct for the engine they run one of the two MGs as a motor, and one as a generator, as I understand.

There's also the limit of the power inverter. If I were to guess, that would be the limiting factor. If the inverter power limit is that same, that explains why the FWD and AWD Sienna are rated at the same power despite clearly having more motor power in theory. We've also seen in various real life acceleration tests that the AWD isn't any faster than the FWD, so I doubt the presence of increased burst capacity.

 

[Dim]

Hi Chubbysumo,
Thanx for your insights. Please keep on sharing.
Yes, Weberauto is a fantastic source of info if you want to understand how things work in hybrids.
Re: regen braking
I've just transferred from '17 Camry Hybrid to Sienna. Camry had excellent regen braking. With over 120K kms (80K miles, 80% highway) I had original brake pads only half worn mostly due to regen braking. Camry Hybrid uses P610 and the feeling was it had a direct connection between the combustion engine and the transmission in regen/sport mode.
I couldn't find any similar mode like that in Sienna so far
@catfish93
I tried manual downshifting, it doesn't produce regen braking anyhow comparable to my experience with Camry Hybrid.