GS450h with 3 motors?

[sfk]

Wouldn't MG1 be free spinning with only the resistance of the bearings?

[mdrobnak]

Wouldn't MG1 be free spinning with only the resistance of the bearings?

No idea. I'd assume it's going to be similar, but not 100% the same as, the locked input shaft situation. The engine is not an 'immovable force', but it's not exactly a weakling starting from RPM=0.

-Matt

[sfk]

I'm starting to think you are wanting to run the hybrid drivetrain intact but with the ICE disabled?

At some combination of torque from MG1 and MG2 the ICE is going to start turning. And the torque required for this is going to roughly equivalent to the torque produced by a 3.5l V6 starter motor.

There isn't a brake band to lock the ICE crankshaft to stop this from happening. It could even happen if MG2 was putting out enough torque on its own.

[mdrobnak]

I'm starting to think you are wanting to run the hybrid drivetrain intact but with the ICE disabled?

At some combination of torque from MG1 and MG2 the ICE is going to start turning. And the torque required for this is going to roughly equivalent to the torque produced by a 3.5l V6 starter motor.

There isn't a brake band to lock the ICE crankshaft to stop this from happening. It could even happen if MG2 was putting out enough torque on its own.

I'm looking to use it in an actual hybrid situation with a different engine in a different chassis. So I need to know if it's gonna do things that's going to cause the engine to have a 'very bad day.'

-Matt

[sfk]

Like jamming a LS or JZ on it?

Depends what sort of hybrid functionality you're hoping to retain.

If you mean "like Toyota intended" with regen braking, stop-start engine, battery charging while stationary etc then it could be quite a thing to get all of the various components in synch along with an aftermarket ECU for your engine management. Lots of reverse engineering but could be done.

If you mean "a normal car with a powerful gearbox" then that would be easier but you'd really need to weld up the gears and then you'll need a torque converter or at least a clutch to separate your constantly running ICE and your gearbox that only turns when the car is in motion. But this approach would be much simpler to manage. You would get diff shredding torque and regen too.

[mdrobnak]

Yes, mostly as Toyota intended. See viewtopic.php?f=11&t=605 for more info.

-Matt

[sfk]

Well if your BMW engine and engine management is reasonably modern (CANbus) you might be able to intercept engine CAN commands from the Toyota ECU and translate them to BMW engine CAN messages? And vice versa. You would do this with a man-in-the-middle CAN bridge perhaps?

I'm out of my depth by now.

[mdrobnak]

Well if your BMW engine and engine management is reasonably modern (CANbus) you might be able to intercept engine CAN commands from the Toyota ECU and translate them to BMW engine CAN messages? And vice versa. You would do this with a man-in-the-middle CAN bridge perhaps?

I'm out of my depth by now.

I can handle the electronics / software piece. It's the mechanical part that I'm having doubts on. I'm not going to do it alone, a shop will definitely be doing some of the labor.

[sfk]

If the torque produced by MG1 = MG2 = ICE no problems.

If ICE > MG1 then MG1 will run faster than commanded and therefore produce negative torque? which will either be damaging or act like regen braking which will effectively lock up the trans and allow more ICE torque through to the rear diff?

Not sure which one...

[slow67]

I am building a drag car, so that’s why I wont lock the input shaft. I’ll weld the PSD in mine so MG1 and the 3rd motor wont fight.

Do you have any motors in mind for MG3?

I have a couple of gen 1 Leaf motors laying around, and a couple of 13" brushed DC motors. I'm considering the Brushed motors since MG1 and MG3 will be limited to around 5400rpm max (because of MG2s rpm in high gear).

[mdrobnak]

That was very helpful in explaining what happens in the Prius prime - which uses both MG1 and MG2.

Long story short - to transfer torque _toward the axle_ - yes MG1 runs backwards, and the engine must be prevented from running backwards (as is already known). The Prius Prime / Plug-in has a clutch which allows it to go forward (for regen purposes / engine additive torque engine scenario) and a clutch which stops the crankshaft from moving backwards, so MG1 can spin backwards and propel the vehicle down the road with MG2.

If I've understood what I've learned so far from Damien's other video on this, and the Prius teardown videos, in order for 100% torque transfer from the engine, MG1 has to be spinning at the same rate as it (because of the planetary gearset). So I think the effective output would basically be (engine || brushed DC motor) + MG2, not (engine || brushed DC motor) + MG1 + MG2. I don't think that's possible, due to the way the gears are set up.

If someone can confirm this who's a mechanical person, that'd be awesome.

-Matt

PS The other video I am referring to is (it would be great to get a copy of this animation up somewhere to play with):

[sfk]

By "(engine || brushed DC motor)" do you mean EITHER DC motor OR ICE engine on the input shaft of the gearbox?

To get them all to co-operate and push the car forward or backward they need to be spinning at the same rate, yes.

The issue I see is that MG1 and your DC motor need to be producing the same torque otherwise the weaker one will be forced backwards by the stronger one??

All of this could be avoided by welding up the front planetary gear...
The only reason to avoid that is if you wanted to use an ICE engine for input, which would stall.

[mdrobnak]

By "(engine || brushed DC motor)" do you mean EITHER DC motor OR ICE engine on the input shaft of the gearbox?

Yep, engine for my situation, brushed DC motor for this thread.

To get them all to co-operate and push the car forward or backward they need to be spinning at the same rate, yes.

The issue I see is that MG1 and your DC motor need to be producing the same torque otherwise the weaker one will be forced backwards by the stronger one??

This, is my understanding the CVT part of the transmission. That the speed ratio between input shaft / MG1 determines the torque which ends up propelling the wheels vs being used for regen. At least...that's what I got out of the deep dive video on the P410 transaxle.

[slow67]

All of this could be avoided by welding up the front planetary gear...
The only reason to avoid that is if you wanted to use an ICE engine for input, which would stall.

This is the correct answer......

[Gigas]

so I guess bolt a nissan leaf motor where the ICE engine was serves no purpose for extra HP - I'm very mechanic and thats the ez part but once you get the electronic and programming n such i'm a bit out of my depth. Could you not use a third motor for regen then?

[sfk]

You would then need 3 inverters if you wanted to add a 3rd motor. Might run into difficulties getting them all to work together? The Lexus RX has 3 inverters, but might not have the power capacity to operate them all adequately.

[Gigas]

You would then need 3 inverters if you wanted to add a 3rd motor. Might run into difficulties getting them all to work together? The Lexus RX has 3 inverters, but might not have the power capacity to operate them all adequately.

My crazy Idea was to run - say a leaf motor(or UQM) where the ICE was as like a boost engine on a completely separate system and then add a switch to either use that motor as a regen motor or boost motor - kinda like NOS from back in the day. But again it's own system but tied to the foot pedal output. So say you want to impress someone - switch on the third motor and really take off but this third motor only have like a 20 mile range that can be recharged once the switch it turn off(regen)

[Isaac96]

Adding a third motor would not decrease efficiency that much
Pulling tons of power for acceleration would certainly decrease your range. But steady-state cruising is pretty similar no matter how many motors you have.

[slow67]

Adding a third motor would not decrease efficiency that much
Pulling tons of power for acceleration would certainly decrease your range. But steady-state cruising is pretty similar no matter how many motors you have.

X2. The Lexus RX400h and Toyota Highlander Hybrid had 3 motors (MG1, MG2, MGR)

[Gigas]

Adding a third motor would not decrease efficiency that much
Pulling tons of power for acceleration would certainly decrease your range. But steady-state cruising is pretty similar no matter how many motors you have.

I'm retro fitting a 2018 mustang GT so why not? I don't really need top end speed as I don't plan on going 150mph on the highway but why not get to 60 as fast as you can - only thing would be working out locking the splined shaft if needed - say a solenoid to lock it when not in use then a switch to disengage it and engage M3 at the same time and go plaid speed - I'm only looking for 80 to 120 mile range I'm ok with that. Now my brain is running off again

[0tik]

Why not use leaf stack or Tesla one for front wheels and leave 250kw of 450h stack at the rear wheels?
Did you go any further into your project?

[Jacobsmess]

Sorry to bump this but it seems a lot of information in here isnt correct. The ratio between the ICE input and MG1 is determined by their speed and directional rotation in respect of one another. It's shown in the deep dive video by Weber/John Kelly on the Subaru (Toyota) Hybrid CVT and various other Toyota CVT videos that by spinning one against the other changes the output shaft speed. This is the CVT aspect otherwise the gearing for the ICE would be fixed ratio, which does not make for a pleasant driving experience.