Subaru Legacy Estate (diesel)

[Scubascooby]

@bratitude
I have been watching some of Damiens YT videos on the Lexus transmission.

It made me curious about the Crosstrek gearbox that you suggested.



It's very clever, why did we not make auto boxes like this before using an ICE and a small electric motor ?

Now I understand how locking the input shaft enables both MG1 and MG2 to drive the EV. Presumably the same is true of the Subaru version.

Using this transmission and it's matching rear diff might be an option if there is space. It would mean that the engine bay would be available for the electronics boxes and batteries.

[Scubascooby]

I've watched that video a couple of times. The section from about 15min shows how various motor inputs affect the output. I'm not sure if locking the input would allow both MGs to drive the output.

Also, they don't seem to be available in Britain, I'm not sure if the XV e-boxer was sold in great numbers. I have found a few in the usa.

https://erepairables.com/salvage-cars-a ... d-57108754

[Scubascooby]

Some useful Crosstrek (E Boxer) info in this thread
viewtopic.php?p=47401&hilit=Crosstrek#p47401

[Scubascooby]

According to https://mobile.guideautoweb.com/en/spec ... phev/2020/

The 2020-onwards Hybrid has a 118hp (88kW) motor.

Power 118 hp (88 kW)
Torque 149 lb·ft @ 1,500 rpm (202 N·m)

This looks like it's only the output of mg1 based on the video above.

If the output of mg2 is the same as the other Toyota/Lexus transmissions then this might be workable.

[Scubascooby]

Nearly a year later and plans have changed although nothing has happened.

I've been watching Damien's videos (evBMW) particularly the ones with the Lexus gearbox which is very similar to the Subaru XV "Crosstrek" 4wd box with 2 motor generators.

The XV gearbox would be a much simpler solution than the Leaf motor and eliminates the original gearbox as well as the ICE. I think it was suggested earlier.

My early understanding was that the Zombieverter could control the motors from the accelerator pedal over CANBUS but it looks like it can do much more.

I can't find a simple list so here is my understanding and question marks:

• * motor control
  * inverter control
  * regeneration ?
  * charge controller
  * BMS ?
  * heating ?

[Phate]

I've been watching Damien's videos (evBMW) particularly the ones with the Lexus gearbox which is very similar to the Subaru XV "Crosstrek" 4wd box with 2 motor generators.

The XV gearbox would be a much simpler solution than the Leaf motor and eliminates the original gearbox as well as the ICE. I think it was suggested earlier.

The Crosstrek PHEV gearbox is the option I liked the most if I end up converting my Forester (or my 2.5 GT if it decides it wants another engine). Confirm this before buying anything but If I remember right that transmission is intended to work with a 3.7:1 rear diff, which is relatively easy to find (the 06-07 WRX has a 3.70 R160 with a viscous LSD).

Even if you don't push the motors harder the stock crosstrek, you're still looking at 1900-2300lbft to the wheels. For comparison (and assuming no losses), my 2.5L non-turbo automatic Forester puts about 1900-2000lbft to the wheels at the torque peak in first gear, and an 05-09 3.0L 6 cylinder Outback puts out about 2500lbft to the wheels in first at the torque peak. So it should move out pretty well.

Some notes from the weberauto video that I left in another thread:

- MG1 and MG2 rotors/stators seem to be the same as the ones in the P710 Rav4 Hybrid transaxle.
- MG1 has 40lbft of torque and MG2 has 149lbft of torque? (not sure how these values were found)
- MG2 to output reduction of 3.4286:1, final drive of 3.7:1, total MG2 to wheels reduction of ~12.686:1 (~1890lbft to the wheels based on 149lbft rating)
- Power is always sent to the front wheels
- Front diff is open because of course it is
- Power split device has 3.6:1 reduction
- Engine to power split planet carrier has a ~1.057:1 reduction
- MG1 with power split device and MG2 with output reduction are on parallel shafts, connected with 0.781:1 gear ratio (effective MG1 to output ratio of 2.8116? aka MG1 to wheel reduction of ~10.403:1? ~416lbft to the wheels based on 40lbft rating)
- Does not appear to use both MG1 + MG2 for forward drive in stock form
- Uses an electromagnetic clutchpack to engage power to the rear axle, the bulk of the "locking" force in the center diff comes from a ball ramp actuator.
- Oil pump has two drive gears with a sprag clutch driven off both sides of the power split device (similar to the L210?) to ensure the oil pump spins when either MG1 or MG2 spin.

[Scubascooby]

I discovered the Forester hybrid and wondered if it uses the same hybrid transmission. I couldn't find any info on it.

[Scubascooby]

The diesel puts out 258 lbft with these ratios

Main Transmission TY758V1AAB
First Gear Ratio  3.454:1
Second Gear Ratio 1.750:1
Third Gear Ratio 1.096:1
Fourth Gear Ratio 0.785:1
Fifth Gear Ratio  0.634:1
Final Drive Ratio 3.700:1

[Scubascooby]

https://legacypic.uk/transmission/searc ... ty758v1aab

So it has a 3.7 diff and looks like it can handle more torque than the hybrid transmission can produce ~3300 lbft

[Jacobsmess]

I'd be very interested to see the Subaru hybrid transmission running. Would be an interesting option for 4wd

[Scubascooby]

With MG1 and MG2 being used to drive, is the inverter sufficient or would a different one be needed ?

[Jacobsmess]

The standard inverter is capable of handling the power limits if both mg1 and mg2. Just because it is being used for traction rather than regen or something else doesn't mean the inverter isn't putting the power through it

[Scubascooby]

In hybrid one mg is used for starting the ICE and charging so I was trying to work out whether it draws on the inverter or not. It must do when starting the ICE but that's relatively short duration.

Does it have to power it to stop it dragging on the transmission ?

[Jacobsmess]

Mg1 needs to handle regen also which goes via the inverter to the batteries so it shouldn't be an issue.

[Scubascooby]

Sorry for the dumb question but why does it invert to charge the battery ? I assumed it would be a charge controller managing that.

I'm guessing that it's not a simple process.

[Jacobsmess]

All power in to and out of the gearbox goes via the inverter, on the standard Toyota setup the hybrid battery is around 230V. This feeds power into the inverter with a boost converter module that boosts the voltage to 650V or thereabouts. When recharging the battery from regen or the ICE the power goes from MG1 into the inverter that then bucks the power down to 230V again.

[Scubascooby]

Thank you.

I've not looked into how to match batteries with the inverter and motor(s).

[Jacobsmess]

no matching is requires. A bettery is agnostic to what it provides power to although the BMS and charging protocols are what distate what the battery can or cant do to some extent. Find a battery that has been reverse engineered or that you are willing to reverse engineer and that matches your space/capacity/voltage requirements.

[Scubascooby]

It was the voltage requirements I was thinking about. I imagine that the Subaru hybrid would have to be powered by a battery with similar specs and not 48V or 800V set up, unless I want lots of smoke

So for example, the Nissan Leaf pack is 92s (x 3.65V ?) gives 335V. Too much for the Subaru inverter ?

[Jacobsmess]

It was the voltage requirements I was thinking about. I imagine that the Subaru hybrid would have to be powered by a battery with similar specs and not 48V or 800V set up, unless I want lots of smoke

So for example, the Nissan Leaf pack is 92s (x 3.65V ?) gives 335V. Too much for the Subaru inverter ?

The inverter if it's the same as the typical Toyota setup is fine from around 230V to 650V. However the boost stage needs bypassing usually as they are current limited.

[Scubascooby]

I haven't yet found any model numbers for the hybrid transmissions.

Here is some info on the various types of diff used in the ICE transmissions.

https://m.awdwiki.com/en/subaru