Toyota / Lexus useful bits

[sfk]

Is the hybrid gearbox in the GS450H / LS600H the only one that could potentially be used in pure electric mode at useful highway speeds (60mph/100kph)? FYI this gearbox has a 2 stage ratio on the output flange. The LS also has a 4wd transfer case. The gearbox is also used in the IS250H but lacks the 2 stage ratio so may have a limited speed range.

There is a HUGE abundance on Prius parts available and increasingly Camry hybrid too. These are both FWD transverse motors obviously so would make a logical choice for FWD conversions (or possibly RWD transverse setups like the MR2).

My question is whether the internal gearing arrangements prevent these gearboxes from being used for high speed in pure EV mode?

[arber333]

Is the hybrid gearbox in the GS450H / LS600H the only one that could potentially be used in pure electric mode at useful highway speeds (60mph/100kph)? FYI this gearbox has a 2 stage ratio on the output flange. The LS also has a 4wd transfer case. The gearbox is also used in the IS250H but lacks the 2 stage ratio so may have a limited speed range.

There is a HUGE abundance on Prius parts available and increasingly Camry hybrid too. These are both FWD transverse motors obviously so would make a logical choice for FWD conversions (or possibly RWD transverse setups like the MR2).

My question is whether the internal gearing arrangements prevent these gearboxes from being used for high speed in pure EV mode?

I dont yet have Prius transaxle at home, so i cant test my principle, but i can tell you Prius/Auris/Yaris inverter voltage sensor goes up to some 400Vdc on the battery side. 12V DCDC converter sadly stops giving 14V at 315Vdc upper limit.
I succesfully revved Leaf motor at 200V up to 8000rpm. At some 4000rpm there is some rasping noise when current limiter keeps control of process, but other than acoustics motor revs up under power and provides regen etc...
I see this as oppurtunity to feed inverter 380Vdc and then using field weakening get motor to higher revolutions. If inverter can provide more than 150A of weakening current we are better than its boost converter with its inductor limit of some 30kW!

[johnspark]

"There is a HUGE abundance on Prius parts available and increasingly Camry hybrid too. These are both FWD transverse motors obviously so would make a logical choice for FWD conversions (or possibly RWD transverse setups like the MR2).

My question is whether the internal gearing arrangements prevent these gearboxes from being used for high speed in pure EV mode?"

i have had made an axle to connect the Prius V2 MG1 and MG2 together. I have had it connected to a manual gearbox and the set up is being installed in a car right now.

I also have had a special device made for the Camry MG1 and MG2 to also use for either direct drive to the differential or go through a gearbox.
So hope to put the Camry MG1/MG2 into the second car i convert. Everything takes so long...

[johnspark]

"I dont yet have Prius transaxle at home, so i cant test my principle, but i can tell you Prius/Auris/Yaris inverter voltage sensor goes up to some 400Vdc on the battery side. 12V DCDC converter sadly stops giving 14V at 315Vdc upper limit.
I succesfully revved Leaf motor at 200V up to 8000rpm. At some 4000rpm there is some rasping noise when current limiter keeps control of process, but other than acoustics motor revs up under power and provides regen etc...
I see this as oppurtunity to feed inverter 380Vdc and then using field weakening get motor to higher revolutions. If inverter can provide more than 150A of weakening current we are better than its boost converter with its inductor limit of some 30kW!"
I do have one at home so can test it. I also have a Gen V3 Toyota Prius inverter at home as well. So when i get the pcb, can test it for you with your help.

[xp677]

The GS450h box needs to be mated to a differential - your maximum speed depends on differential ratio, but generally lower is better due to the high torque of this motor.

Prius etc has an inbuilt differential, should be able to achieve max vehicle speed on motors alone, otherwise MG2 would overspeed when driven by the engine. Whether the motors are powerful enough depends on your application.

[jnsaff]

I went through the Weber Auto Prius Transaxle evolution video series at https://www.youtube.com/playlist?list= ... FsyuDx8ow_ and I got the impression that P410 (that is 3rd gen Prius) is the first one that has the MG1 speed reduction device and allows to run at high speeds in pure EV mode without overspeeding MG1. Both motors rated at 13KRPM.

P610 is a redesign and both motors are rated up to 17KRPM.

The P610 power rating is lower than P410 although final drive ratio is higher and compensates for loss of torque but may cause issues with higher speeds.

The Prius Prime version has a sprag clutch on the motor input so it can use MG1 to drive the car as well and might save people from locking the input shaft to the housing.

I want to explore whether I could convert a 2003 Mini to using a P410 or P610.

I also have a Saab 95 2003 that I’d love to convert but it’s a heavy car and I’m note sure either of those Prius transaxles would be enough.

[jnsaff]

So looks like only the Prius Prime (Plug in) with the EV mode has an electric oil pump and rest have their oil pump driven from the ICE engine shaft. I guess this would be one reason why we can’t find any Prius transaxle based conversions?

[arber333]

So looks like only the Prius Prime (Plug in) with the EV mode has an electric oil pump and rest have their oil pump driven from the ICE engine shaft. I guess this would be one reason why we can’t find any Prius transaxle based conversions?

If you can get to the oil pump then you can replace it with a relevent 12V aux pump version from another car.

[streber]

Does anyone know if you can take the transfer case from a LS600h and attach it to a GS450h gearbox? Looks like there is a section to unbolt on the GS450h, but unclear if it matches up with the LS600h transfer case exactly.

[sfk]

I'd say almost certainly, but can't actually confirm.
The GS450h gearbox is L110 and the LS600h one is L110F. To me it looks like the rear transfer case is the only thing different.

[streber]

May just have to buy a transfer case and try my luck. I've got a E46 325xi wagon that I'm converting and would be nifty to keep the awd. I figure sorting out two custom driveshafts is way easier than trying to figure out how to mate the Lexus transmission to the BMW transfer case.

[Kevin Sharpe]

May just have to buy a transfer case and try my luck.

I discussed this with Damien and if I understand correctly the transfer case is a bolt on option. It's also available in two versions, permanent AWD (as fitted on the 600H) and with high/low range selection

[sfk]

That's interesting. Which vehicles had the high/low ratio transfer case? Is this a common transfer case format used for non-hybrids such as Hilux?

[jnsaff]

So I've been racking my brain up with this Prius transaxle thing as I have at least one FWD car I'd like to convert and there have been several unknowns about. There is the internal oil pump one and then there's the welding of the internal gears to lock the MG's together physically.

Now as mr Weber Auto states if two parts of the planetary gears rotate at the same speed that will also make the third one rotating the same speed. This would then mean that if we would drive MG1 and MG2 at the same speed (possibly correcting a bit for the differences in gearing) then the now disconnected engine shaft would also run the same speed and therefore also drive the engine oil pump?

Is this right or am I missing something really obvious? The gen3/4 transaxle MG's should be capable of same rotational speeds and without welding it there would be some (tho not sure how useful) possibility to vary the rotational ratios of the MG's.

Also found a C-HR P610 transaxle for sale for a little bit more than 200 euros and am super tempted. Tho this would probably mean reverse engineering the gen-4 inverter/converter.

[konstantin8818]

Now as mr Weber Auto states if two parts of the planetary gears rotate at the same speed that will also make the third one rotating the same speed. This would then mean that if we would drive MG1 and MG2 at the same speed (possibly correcting a bit for the differences in gearing) then the now disconnected engine shaft would also run the same speed and therefore also drive the engine oil pump?

Is this right or am I missing something really obvious? The gen3/4 transaxle MG's should be capable of same rotational speeds and without welding it there would be some (tho not sure how useful) possibility to vary the rotational ratios of the MG's.

You understood it correct. When welded, all three shafts rotate at the same speed. That means you can made MG1 and MG2 work together to propell your car.
If sattelite gears not welded, it becomes more complicated. You have to somehow syncronize MG1 and MG2 via software, otherwise oil pump will not operate. Or you need to block MG1 from rotating, but I believe continuous sattelite gears rotation is not good.

[xp677]

If you don't lock the input shaft, then MG1 will spin the input shaft, rather than passing its torque to MG2 and the output shaft. If you want to use MG1 to provide torque to drive the vehicle, you need to lock the input shaft (and with it, the mechanical oil pump).

You can test this by spinning MG1 on its own with the transmission on the bench. The input shaft will rotate. Grabbing hold of the input shaft will cause the output shaft to rotate (in the opposite direction).

If you only plan to use MG2 to move the vehicle, then you can indeed find a relative MG1 speed to spin the input shaft to turn the mechanical oil pump as required. This seems rather wasteful. The OEM electric oil pump on the GS450h is a 600W unit, which weighs significantly less than MG1. I imagine the Prius has a similar pump.

[jnsaff]

Ah! I get it now! When the shafts are not welded together the torque goes to the least resistance which will be the unconnected engine shaft where there is essentially no resistance! That’s why the Prius PHV has a sprag there to stop that from happening. The sprag tho wouldn’t help us as we need that shaft driven oil pump for cooling.

Only the PHV version of the Gen4 has an electrical oil pump, retrofitting that is probably much more hassle than just welding the PSD together.

Thank you!

[GaryClarke]

As I understand it, the important difference is that the GS450h transaxle original purpose is in a rear wheel drive set-up but the Prius/Yaris/Auris is for front wheel drive. The RWD set-up feeds power to an external differential; the FWD has an internal differential - the Power Split Device. In both cases, we seek to combine the power output from MG1 and MG2. but because of the difference in design, this achieved in different ways.

For the RWD we combine the output by immobilising the input shaft externally by making a bracket that locks the shaft to the transaxle casing.

This approach would not work with the FWD because the internal PSD would still allow the MG1 &2 to move independently of each other. Instead, the FWD the transaxle must be disassembled partially; the PSD removed. The planet/satellite gears of the PSD are welded to the outer ring gear and the transaxle reassembled.

However, we still need to split the power between the drive wheels. How do we do this?

[jnsaff]

There is a regular differential after MG2. PSD combines MG1/MG2 and the ICE and is a completely separate from the differential. As I understand having an electric oil pump on the GS450h means that if it is used instead of the engine driven one there is no need to open up the transmission and find a good place to weld them together as bolting something on the input shaft is much easier.

[GaryClarke]

However, we still need to split the power between the drive wheels. How do we do this?

Thanks jnsaff. Two minutes of googling answered my own question. Embarrassingly, it was a questioned I'd already solved months ago. But I've been so fixated on getting my head around the MG power combining that I'd forgotten.

[Sloth]

Searching for the GS450h gearbox and inverter, I noticed that in the description of the auction of parts coming from UK (RHD), the inverter has different leads than the LHD version. Do you know which pins are exchanged?

beware the gearbox without oil pump, they are half price

[xp677]

I think I covered this in my thread. I believe the MG1 and MG2 outputs are swapped on the LHD units.

Its easy to tell if you have a system to hand. The motor cables are labelled and the rubber boots on the inverter ends are different lengths. You can compare them to engine bay photos of the car.

You could also connect up just one motor and resolver and run the inverter at 12v to see if you connected it correctly.

According to the service manual, the control cable pinout is the same.

https://openinverter.org/wiki/File:Inve ... nector.png

[RE3Rotor]

Do we know if the inverter from a Lexus HS250h is similar to any other inverters? Judging by the size of the vehicle, I am guess it is closer to the Prius?

[xp677]

I've never heard of the HS before. Inverter looks similar on the outside, might be worth a shot? Maybe get one and see.

[RE3Rotor]

It looks the same as the GS450h inverter (MG1&2 connectors look the same as the GS) but it has the same 2 plug on the control side as the Camry inverter. I am not an EE so I am more weary about picking something that may not work with all your work so far. But at half the price of the GS450h inverter, I just might pick this one up.

https://www.ebay.com/itm/10-12-HS250H-D ... SwM~ddu0wm