CVT application on Toyota/Lexus gearboxes

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Jacobsmess
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CVT application on Toyota/Lexus gearboxes

Post by Jacobsmess »


At this point in the video this guy demonstrates the CVT ratios by controlling the MG1 speed and direction, as I understand you need the ICE input to be moving to achieve this but it's got me wondering, has anyone experimented with this? I guess a small electric motor on the input could be enough (aka fruitloop setup :D ) to get higher speeds, I was mostly thinking about it with regards to the IS/GS 300H transmission which may be more limited with its gearing... or not....

anyway, this was interesting to me, I suspect it applies to all the Lexus/Toyota eCVTs
Woodfie
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Re: CVT application on Toyota/Lexus gearboxes

Post by Woodfie »

Have been fascinated by the E CVT for many years. As the high efficiency it achieves over other variable speed control methods, belts, endless chains etc.

With regard to experimenting with this, have had bench set ups with a separate torque control input for MG1, and another for MG2..
Then progressed to applying an input ICE to the splined shaft. The ICE speed is selected and set with a potentiometer to say 1500rpm,
This is independent of MG2 being at stand still or turning to drive the vehicle.
The rotating ICE is then supplied fuel, at this stage LPG injected in the inlet to stoichiometric ratio, and throttled to over speed the MG1 set speed. This then tries to lift MG1s speed, and has the effect of it becoming a generator, and power returning to the Hv bus, to be used by MG2, or returned to the Battery..
Basically a range extender...

Some limited test runs in a Bedford Campervan have been successful in maintaining battery Soc for short distance driving..
Jacobsmess
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Re: CVT application on Toyota/Lexus gearboxes

Post by Jacobsmess »

Woodfie wrote: Thu Nov 23, 2023 8:08 pm Have been fascinated by the E CVT for many years. As the high efficiency it achieves over other variable speed control methods, belts, endless chains etc.

With regard to experimenting with this, have had bench set ups with a separate torque control input for MG1, and another for MG2..
Then progressed to applying an input ICE to the splined shaft. The ICE speed is selected and set with a potentiometer to say 1500rpm,
This is independent of MG2 being at stand still or turning to drive the vehicle.
The rotating ICE is then supplied fuel, at this stage LPG injected in the inlet to stoichiometric ratio, and throttled to over speed the MG1 set speed. This then tries to lift MG1s speed, and has the effect of it becoming a generator, and power returning to the Hv bus, to be used by MG2, or returned to the Battery..
Basically a range extender...

Some limited test runs in a Bedford Campervan have been successful in maintaining battery Soc for short distance driving..
Thanks, I'd love to see any pics of videos of this. I'm mostly interested in how it can be used to provide traction. Did you test this at all in your setup?
Woodfie
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Re: CVT application on Toyota/Lexus gearboxes

Post by Woodfie »

Yes, tested on the bench/floor, with MG2 locked with parking pawl, initially with manual control of torque request, and engine throttle/Lpg fuel adjusted to give 6 to 8 kw charge to battery.
Next was installed in the van, and test run on a circuit, to have MG2 as traction, and MG1 providing a charge of 6kw, as MG2 was going through accelln, flat running or deceleration. A few promising runs done , the aim is to get a feel of how well this can maintain, when out on the road.. Have operated a Toyota Coaster series hybrid Electric bus, modified to Phev in this way and was satisfactory, so aim is to emulate similar behavior.
Owing to a ph storage fail, have only a few rescued snips and pics. Am seeing if can recover from some which had shared, and will put these up, along with new pictures.
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Clrs
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Re: CVT application on Toyota/Lexus gearboxes

Post by Clrs »

So, basically when ICE is at full throttle the MG2 just spins freely without any action, right? MG1 acts as a generator to power up the battery and selects its speed to make an infinite number of gears according to ICE speed and vehicle speed, right? If I manually apply current to MG2 while ICE is at full throttle, will MG2 add its full power and torque to help ICE to accelerate the car? Will ICE and MG2 torque combine?
Thanks.
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