GS450H Discussion

[slow67]

TransSP is there to disengage the Electric Oil Pump when the mechanical oil pump is providing oil pressure (when input shaft of gearbox is spinning)?

No, TransSP controls overall oil pressure in the trans. The trans has 2 pumps, the electric one is somewhat slow to respond, and we can't control the speed of the mechanical pump. The 2 pumps converge (through check valves). Then the TransSP solenoid determines the pressure of the system overall. We can probably manage the pressure with the pwm of the electric pump for those not turning the input shaft, but mine will have a 3rd motor on the input shaft. Most times, the goal is to produce ample pressure with the pump, then regulate pressure with a pressure regulator after the pump. See attached picture as well.

[xp677]

TransSP is there to disengage the Electric Oil Pump when the mechanical oil pump is providing oil pressure (when input shaft of gearbox is spinning)?

Don't forget that you can disengage and electric pump simply by turning it off!

The SP solenoid is just a bleed/bypass solenoid. These are common in automatic transmissions to control line pressure. Sometimes manual (as in older units such as the A340 series), sometimes electronic.

[slow67]

TransSP is there to disengage the Electric Oil Pump when the mechanical oil pump is providing oil pressure (when input shaft of gearbox is spinning)?

Don't forget that you can disengage and electric pump simply by turning it off!

The SP solenoid is just a bleed/bypass solenoid. These are common in automatic transmissions to control line pressure. Sometimes manual (as in older units such as the A340 series), sometimes electronic.

X3! Sometimes I have trouble putting things into layman's terms.

FYI with the oil pump set to 100 (~40%) PWM the TransSP solenoid can make the pressure switch open with as little as 2.5% pwm. I need to find an adapter and put a pressure gauge on it.

[xp677]

One thing that would be good to know, is how much the oil pump contributes to lubrication and cooling. Whether it needs to run at a high rate all the time or not, if it should be temperature controlled and if that would make a difference, or maybe it's fine to just run at a low speed, and increase the speed for gear shifts.

[slow67]

One thing that would be good to know, is how much the oil pump contributes to lubrication and cooling. Whether it needs to run at a high rate all the time or not, if it should be temperature controlled and if that would make a difference, or maybe it's fine to just run at a low speed, and increase the speed for gear shifts.

Well the case has a heat exchanger which will cool the case all the time (along with air passing over the case). Most ICE setups base pump pressure purely on load (to hold the clutches). You should be fine basing pressure purely on torque input. You could easily increase pump pressure if the temp gets too high to pass more fluid up to the heat exchanger.

[xp677]

I'm not sure that answered my question at all. What is the reasoning behind basing it on torque input? As additional cooling?

You mention a heat exchanger, does this mean that water does not circulate in a jacket around the motors? Is motor cooling done only by oil?

Would there be sufficient lubrication without running the motor at all? I imagine not as the shaft sits higher than the oil pan.

[sfk]

You mention a heat exchanger, does this mean that water does not circulate in a jacket around the motors? Is motor cooling done only by oil?

There is an integrated AFT to coolant heat exchanger for the gearbox. The motors sit in a pool of ATF fluid though it might be different formula for this application rather than common ATF. The heat exchanger transfers heat from the gearbox to a coolant circuit. I don't know it this is separate or shared with the ICE coolant and cabin heater circuit.

[slow67]

I'm not sure that answered my question at all. What is the reasoning behind basing it on torque input? As additional cooling?

You mention a heat exchanger, does this mean that water does not circulate in a jacket around the motors? Is motor cooling done only by oil?

Would there be sufficient lubrication without running the motor at all? I imagine not as the shaft sits higher than the oil pan.

The reason you base it on torque input, as the clutch packs are applied with hydraulic pressure (for MG2). Without pressure, they will slip and burn. You need enough pressure to hold them applied without slipping.

Correct. The motors are cooler with ATF flowing throughout the trans.

No, there is no lubrication without oil flow. All the bushings and bearings would fail without the pump running (in addition to clutches slipping).

[xp677]

Thanks for that.

I don't intend to use the solenoids, I imagine that the clutches are open in this case, and there is no potential for slip? Where did you find this info on the transmission? I've not seen any technical drawings of it.

Strange that the car has a heat exchanger within the transmission, and also external oil cooling up front. I'd have thought that especially with the increased load in our projects, an external oil cooler would be required, with a pump speed set relative to oil temperature (assuming constant coolant flow).

Edit:

Reading through this document (page 50, marked as 41) https://www.osti.gov/servlets/purl/947393

It seems that for either "high" or "low" one of the actuators needs to be activated at all times, so it looks like a rising rate of oil flow would be needed at all times, regardless of gear selection. If this is the case, then I imagine that one of the actuators is closed by spring pressure, and opened by oil pressure through the relevant solenoid?

[sfk]

It seems that for either "high" or "low" one of the actuators needs to be activated at all times, so it looks like a rising rate of oil flow would be needed at all times, regardless of gear selection. If this is the case, then I imagine that one of the actuators is closed by spring pressure, and opened by oil pressure through the relevant solenoid?

Yes there are 2 clutch packs and one of them has to be engaged to transfer drive to the output shaft. Without any clutch packs engaged MG2 will spin freely.

[sfk]

Strange that the car has a heat exchanger within the transmission, and also external oil cooling up front. I'd have thought that especially with the increased load in our projects, an external oil cooler would be required, with a pump speed set relative to oil temperature (assuming constant coolant flow).

The heat exchanger is likely to me housed externally to the main casing. There will be an oil entry and exit port which are probably hidden under the mating surface. There will also be an external coolant entry and exit, a couple of hoses leading forward to the radiator most likely.

Something like this?

[xp677]

It seems that for either "high" or "low" one of the actuators needs to be activated at all times, so it looks like a rising rate of oil flow would be needed at all times, regardless of gear selection. If this is the case, then I imagine that one of the actuators is closed by spring pressure, and opened by oil pressure through the relevant solenoid?

Yes there are 2 clutch packs and one of them has to be engaged to transfer drive to the output shaft. Without any clutch packs engaged MG2 will spin freely.

I understand that, but my belief was that you can run this unit with neither SL1 or SL2 energised. From my basic bench testing, I seemed to gain a reasonable torque with neither solenoid energised. Is this not the case?

The heat exchanger is likely to me housed externally to the main casing. There will be an oil entry and exit port which are probably hidden under the mating surface. There will also be an external coolant entry and exit, a couple of hoses leading forward to the radiator most likely.

It's mounted on the right hand side, one of the hoses is mounted to it's cover plate. The other must pass through the transmission since the hose entry is on the other side.

[sfk]

I understand that, but my belief was that you can run this unit with neither SL1 or SL2 energised. From my basic bench testing, I seemed to gain a reasonable torque with neither solenoid energised. Is this not the case?

Sorry, not able to comment as I don't have a L110 in my possession for bench testing. I'm working on what I have read and seen in pictures!

What happens if you run it with no solenoids energised and no oil pressure? There may be some sort of failsafe arrangement whereby if both solenoids have no signal 1 will engage (possibly mechanically) to ensure control of the car is maintained but this would require oil pressure still. Running the gearbox without oil pressure would show if this is the case. I expect in this test scenario the MG2 would just spin, though there could be a bit of mechanical drag that makes it to the output shaft and gives the impression of being engaged.

How much torque did you observe? Enough to move a car? Or more than could be stopped with your hand?

[slow67]

Running it with both solenoids LOW (and with oil pressure) puts it in high gear (1.9:1 ratio). BUT without running oil pressure with any load the clutch plates will slip.

If you run it without oil pressure, the reason the output shaft turns is the motor is ALWAYS turning the gears, and the drag of the bushings/bearings/teeth allows a little power to be transferred to the wheels. You will see this with any GM Powerglide transmission as well (if someone revs the motor in neutral, the car rocks).


Also, I think I found a a pressure port. It's 1/4" NPS thread. I'm hoping its not a cooler port (will be lower pressure than line pressure). Although this port appears it might be an external oil cooler port on the LS600h.

[xp677]

How much torque did you observe? Enough to move a car? Or more than could be stopped with your hand?

More than I could stop with my hand. Which isn't an accurate measure, but I'd have thought that my hand can overcome friction in a pair of freely-spinning planetary sets!

This was running at around 100rpm. Oil pump wasn't running at this time either.

[slow67]

With a powerglide in neutral, its enough torque to make a 3,000lb car jump forward enough to have to grab the brakes when the ICE revved.

[xp677]

That sounds like a terrible transmission. I've never seen a Toyota transmission do that.

[sfk]

If you run it without oil pressure, the reason the output shaft turns is the motor is ALWAYS turning the gears, and the drag of the bushings/bearings/teeth allows a little power to be transferred to the wheels. You will see this with any GM Powerglide transmission as well (if someone revs the motor in neutral, the car rocks).

This makes me think that if you a using the L110 with a welded up front planetary gearset, even if you come to a complete stand still and lose mechanical oil pressure, after a bit of clutch slip from the electric motors when the start spinning, the mechanical pump will regain pressure and engage the clutch packs again.

Does this mean that you could ignore the electric oil pump entirely if set up this way?
Not ideal for clutch wear obviously, especially if you floored it from a stand-still. But if you drove carefully...

[slow67]

This makes me think that if you a using the L110 with a welded up front planetary gearset, even if you come to a complete stand still and lose mechanical oil pressure, after a bit of clutch slip from the electric motors when the start spinning, the mechanical pump will regain pressure and engage the clutch packs again.

Does this mean that you could ignore the electric oil pump entirely if set up this way?
Not ideal for clutch wear obviously, especially if you floored it from a stand-still. But if you drove carefully...

You could do this. I would take off with only MG1 and the external motor. Then you could monitor PB1 and PB2 switches, and as soon as you see the correct pressure switches open/close, you could command torque to MG2 again. It wouldn't be the greatest for longevity, but it could work. You would definitely need to control SL1. Maybe Rev3 of Damien's board will hook this to a PWM output if software PWM doesn't cut it.

That sounds like a terrible transmission. I've never seen a Toyota transmission do that.

Thats because the input shaft always drives the planetary gears (this transmission was designed in the late 1940s). Most modern transmissions have a clutch pack that disengages the input shaft before the planetary gearsets. Despite this, it is the most popular transmission in the drag racing world.

[mdrobnak]

Lets talk flywheels...

So if we compare a traditional flywheel for an auto gearbox - say this one: https://www.ebay.com/itm/2009-2017-BMW- ... 3506693485

and we compare it to the transmission:

https://www.ebay.com/itm/2009-2011-LEXU ... 3766966717

and we note a problem - that looks more like a manual transmission.

And the flexplate confirms this:
https://www.ebay.com/itm/Flywheel-Flex- ... 2864066693

Anyone have any diagrams which show how this is supposed to work? I'm a little lost on how I'd get the transmission to mate with something like that BMW flexplate. (This is why I stick to wiring harnesses, electronics and code. )

-Matt

[sfk]

Your best option is to find a flywheel from a car which uses the same ICE engine but has a manual transmission and clutch. Then try to find a clutch pack that has the internal spline that matches the ICE input spline on the Lexus transmission (probably Toyota) while fitting inside the clutch basket of the ICE flywheel.

From what I understand you want to allow the ICE to idle which means keeping the MG1 planetary gear unwelded up. You wouldn't need the functionality of the clutch so it doesn't need to disengage. Just transmit engine torque.

Another idea would be to engineer an adapter from the auto flywheel to the input spline on the Lexus. There are mounting holes on the flywheel for the flexplate. But this is a precision engineering job requiring balance and alignment.

[xp677]

The lexus coupler comes in two parts, one is the engine flywheel, the other is a sort of flex plate/clutch centre combo. You could just bolt this part to the flywheel of your chosen engine. Of course, you would need to drill the appropriate bolt holes, balance the assembly, etc, but this is not uncommon.

Alternatively, you can have a custom flywheel made to take the Lexus coupler.

I am using the Lexus coupler, without the flywheel, for my project. I just bolted the spline plate to the front transmission mount. You could just as easily bolt it to a flywheel. I'd recommend using a coupler such as this, as it has the dampener built in (springs).

That eBay listing is very expensive, I paid £20 for mine from a wrecker.

[steveknox]

Hi all,
I'm testing my motor(s) with my own inverter prior to getting Damien's board set up.
Does anyone know how many pole pairs are in these motors, or have any documentation on the specs of these motors?

[xp677]

Have a look at this document:

https://www.osti.gov/servlets/purl/947393

Ignore the info on the inverter, it's not the same as the GS.

The transmission and motors are the same as the GS, however the LS600h has a transfer case on the rear.

You should be able to find plenty of info on the motors from page 46 onwards.

For a similar document regarding the inverter, see here:

https://www.osti.gov/servlets/purl/928684

Again, ignore the transmission part of this document. It's a FWD unit with many differences to the GS.

[ZooKeeper]

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