MAX Weight

1&2. The current Scangauge will not display any CAN messages, which the ones you want are. They are "working on it - real soon now". If you have one, you will have to send it back to them to have it updated. Best to ask them which messages they plan to add.
4. There really isn't a "CVT" as most of us think of one. The MGs are used to change the spin rate, sort of a magnetic CVT. Check out the sticky postings at the top of this page to visualize how it works. I'm not going to try to explain, as if I do my headache will get worse.

 

I think David was referring to the two ''sticky" topics listed at the top of this Prius Technical Discussion forum: CAN-View Software Updates and Introduction to Prius Power Flow. The first may tell you what CAN-View reports and the second explains how the Prius sends power to the wheels to move the car and load.

The HSD can not slip, it's all gears in fixed ratios. Speed and power to the wheels is varied by electronically changing the direction and speed of MG1 and MG2 and the speed of the ICE. Torque is what moves the car forward (or backward) and it is the computer that balances your accelerator pedal position demand with the available motive forces.

The headache comes from trying to understand the planetary gearing of the HSD and the computer's algorithms for acceleration.

 

As I best understand it (hopefully someone will correct me if I'm mistaken):

<div class='quotetop'>QUOTE(Devil's Advocate @ Sep 19 2007, 01:55 PM) [snapback]514903[/snapback]</div>

Not yet. Perhaps "soon".

<div class='quotetop'>QUOTE(Devil's Advocate @ Sep 19 2007, 01:55 PM) [snapback]514903[/snapback]</div>

Not that I'm aware of, but hopefully if someone is aware of such a completed project they'll see your question.

<div class='quotetop'>QUOTE(Devil's Advocate @ Sep 19 2007, 01:55 PM) [snapback]514903[/snapback]</div>

Given enough time and enough resources. . . . I don't see why it wouldn't be possible.

<div class='quotetop'>QUOTE(Devil's Advocate @ Sep 19 2007, 01:55 PM) [snapback]514903[/snapback]</div>

Not sure that I understand the question.
Assuming you know what a planetary gear is, the ICE is connected to the "planets", one Electric Motor/Generator is connected to the "sun", the other Electric motor/generator and the wheels are connected to the "ring". Depending on the request from the accelerator pedal, the computer determines the "best" combination of torque to add from each of the three sources.

<div class='quotetop'>QUOTE(Devil's Advocate @ Sep 19 2007, 01:55 PM) [snapback]514903[/snapback]</div>

The drive ratios are fixed and don't change. The CVT can add torque directly by sending electricity to the MG connected to the ring. It can also choose an ICE rpm to generate a chosen amount of torque, and then choose how much this force at the planets affect the ring by sending electricity to the MG connected to the sun.

<div class='quotetop'>QUOTE(Devil's Advocate @ Sep 19 2007, 02:24 PM)</div>

As far as I know, there is no clutch. There is nothing to slip, except perhaps the wheels spinning on the road. At that point the traction control would kick in and reduce power. and the car wouldn't move.

The computer will use the ICE and the electric motors/generators to send power to the wheels as it sees fit to try and move the car. If a load was so high that the car won't move and if the wheels were somehow prevented from slipping, I suspect the car would end up in "force charge" mode, where the ICE rpm spins the sun and the ring/wheels don't move. The sun spins the generator and charges up the battery until it reaches it's charge limit.

 

I think I read "Bilsonforweb" is working on an HSD cooler (for his Prius classic). He plans on using the fill and drain plugs for inlet/outlet with an external oil pump. More oil would have to be added, of course, due to the extra volume in the pump, cooler, and lines. More oil is always a "good thing". Except when you have to pay for it.

 

I have towed a yamaha 4 wheeler on my small 4x8 utility trailer 140 miles no problem in any areas.

but then the weight was very minimal trailer tonge weight only 30 pounds and the atv 397# was just like having 2+ of me in the back seat oh and 24# of petro in jerry can.

[attachmentid=11543]

 

You really don't want to do this. Along with possibly shattering the CVT your braking ability will go to hell.

 

I helped my brother move last fall. The trailer was full and the motor seemed to be working pretty hard but it handled the load just fine. Most of the strain was caused just by the extra drag of the trailer:

 

Maximum torque the engine plus motor can deliver into the HSD gearing is 515 N-m or 380 ft-lb. There is a reduction gear between the HSD and the wheels, and I can't find the ratio at the moment, though I remember seeing it somewhere. It was between 1.5 and 3, as I recall.

Anyway, this gives you an idea of the forces the system is designed to handle.

 

<div class='quotetop'>QUOTE(benighted @ Sep 19 2007, 10:11 PM) [snapback]515095[/snapback]</div>

And what was the weight?

 

<div class='quotetop'>QUOTE(David Beale @ Sep 20 2007, 10:07 AM) [snapback]515246[/snapback]</div>

Not that I don't believe you, but I'm just curious if you have a source for this information?

<div class='quotetop'>QUOTE(David Beale @ Sep 20 2007, 10:07 AM) [snapback]515246[/snapback]</div>

Does anyone else know what the gear ratio is in this reduction gear, hobbit perhaps?

 

<div class='quotetop'>QUOTE(Devil's Advocate @ Sep 19 2007, 03:45 PM) [snapback]515010[/snapback]</div>

As Danny noted the maximum Force is 380ft lbs. However, I doubt that is really the answer you were looking for. You probably want to know how steep a hill you can go up while pulling a trailer, and/or how fast you can go up a certain grade. It can be calculated, but you would have to eliminate the power from the motor in the calculation, since eventually the battery would run low.

If you did the calculation you would find that you would be calculating a maximum speed based on a certain percent grade and total weight of your prius + load. Their would be a maximum grade at which the Prius would not be able to move at all, but that will probably not be an issue. In the end you will be able to ascend any grade, just not necessarily as fast as you would like.

 

04 final gear ratio is around 4.13 from my memory.

MG2 can output 295 lbs-ft max at 0 rpm.
Gas engine max torque is 82 lbs-ft at 4500 rpm(?) but only 72% get split to the wheel.

Total output torque is about 1,462 lbs-ft (295+82*0.72*4.13).

In your situation, the torque in PSD will not change. Just MG1 and MG2 will get utilized more and can overheat if cooling system can not handle.

 

There will not be more than a few percent margin on that torque number.

As far as the design for the transmission gears, yes at least a 50% margin to ensure a reasonable fatique life.

 

My numbers are from Toyota documents, which I don't have the url for at this time, of course. It's the one that discusses the difference between the "new" THS II and the classic THS, with photos of the various parts, drawings, and the specification sheet, from which I got the numbers. I printed it out and promptly lost the URL.

 

<div class='quotetop'>QUOTE(Devil's Advocate @ Sep 20 2007, 10:46 AM) [snapback]515338[/snapback]</div>

Yeah, it was a brick and pulled about the same empty (round trips are cheaper), there was a LOT of drag but it handled fine. Averaged about 29MPG.