high torque capable ivt 2

[bigfish]

Hi all'
I just caught the end of the 12 gear transmission thread for cars.I take it you are all highly qualified and have experience in the transmission field[something I do not have].But I can normally recognise a good concept when it arises and the fact I am a share holder in this company is neither here nor there.
All I am asking for are any comments anybody might have to make from a professional point of view on the series 3 ivt transmission being tested by Ford, GM at the moment from Torotrak.Maybe you have been unaware of the possible introduction of toroidal transmissions in the very near future to replace the conventional auto.Jatco are trying hard to make their half toroidal unit work with high torque engines but can't achieve the fuel gains of the Torotak design.Curiously it is based on the old Perbury design that one of you drove several years ago,only difference being the whole operation is controlled by computer now and hydraulics for the operation of the rollers.Traction fluid has been produced in a joint venture with [Shell]and the system is proven to save 25% fuel over a 4 speed auto and 17% over a manual.GM have also said wear on the componants is no further an issue with them [as there is none]and they are now evaluating the system put into a large 5 litre Siverardo suv.Other points,BMW have now requested the architecture of the design and are going ahead with a design for one of their high powered vehicles via Getrag also a licencee of Torotrak.Although on the downside Toyota pulled out of a licence last year stating vibration as the cause.Toyota did all their build on the ivt themselves with nothing to go on except the drawings[they desired no help from Torotrak in developement].My personal idea is [this is the way the Japanese like to work].Ivt is proven to work with no vibration and has good driving characteristics like the ability to mimic gearchange of an auto incase this is what is asked for and can also be driven as a configured manual with any possible setting.
Well thats my opinion,I,d love to hear opinions from those with the knowledge[good or bad].The whole thing is kept low profile, as is normal in the auto industry and Torotrak have a contract stating confidentiality execpt for the six month company reviews.I will continue to hold these shares simply because if they make the big breakthrough they will go through the roof but my question is from the professional side.
Thanks for your time.
Their website is

http://www.torotrak.com

 

[GregLocock]

The problem early on with the Perbury was that the contact pressure between the disk and the plate was high - which it had to in order to transmit the force in shear, via an oiled, steel surface.

This high pressure caused rapid fatigue failure of one or other surface(probably the disk). It looks as though they have reduced the radial load required by choosing a more suitable lubricant.

The change in concept, using the epicyclic system in parallel, will also help with that. Cheers

Greg Locock

 

[Torotraker]

BigFish try going to

http://www.torotrak.org.uk

for the latest information and updates on Torotrak.
regards
Torotraker.

 

[GraviMan]

This looks like a good system, especially the castoring idle mech. It will certainly replace fluid coupled auto boxes. The case for CVT vs IVT will depend on cost and compactness of the Torotrak system. There is some slipage in the fluid contact mech so efficiency is ~95% from memory. This may rule against all manual boxes being replaced since helical gear contact is 99%, most losses being the unclutched gears stirring up the oil. Competition is all about efficiency, so we may not see a race or rally Torotrak.

Likely to get into agricultural machinery in a big way though. In fact I would be curious as to whether 2nd generation Torotrak systems end up having 4 Torotraks replace the conventional 4x4 gearbox, centrediff, front and rear diff system used in Land Rovers - there are very major off road advantages. Again this depens on cost and compactness.

For my mind the idea of a powertrain that just delivers the power it's told to can't be bad.

Mart

 

[evelrod]

Actually a race or rally CVT would be an excellent place to showcase the drive system. At best it is going to be an uphill battle to get public acceptance of this type of drive. I see this as the major problem from what is now happenig in the BMW showrooms with the new Mini CVT (it is rated at less HP and lower mileage, too). I haven't driven a new Mini yet but, I did drive an NSU many years ago and all I remember is that the thing was a DOG! That is MY preconception and I would be in that vast class of potential buyers(probably not).
With F-500 in SCCA being a very successful class for the last 15 years there is precidence. All it would take is for one major mfgr with enough $ and forsight to commit to building enough cars to make the class work (that means -sell them cheaply to the racer). Sorry, but I just don't see a VAST future for CVT or IVT. At least not as the technology stands at present.

Rod

 

[aorangi]

Hi Rod !

Don't you confuse NSU and DAF ? To my knowledge NSU's cars were never fitted with a CVT. By the way, CVTs were successful in racing (in 1967 with DAF- Brabham- Cosworth F 3 ) but were banned by the FIA in 1994.
See:

http://www.ritzsite.demon.nl/DAF/DAF_cars_p17.htm

The Audi Multitronic works fine, accelerates better than a manual, has more mileage and sells well. They are actually doing a lot of R&D on the concept. A new chain and a two ranges powersplit system will extent the ratio span and the torque capacity to 500 Nm.

SKF is developing a "CVT by wire" in which the hydraulic control system is substituted by an electro-mechanical actuator acting directly on each pulley. It is intended to work with an ISG (Integrated Starter Generator) equipped vehicle.

Van Doorne engineers are considering how to compound a V belt variator with a geared neutral system in such a way to obtain an IVT.

Several new CVT systems such as the Milner are also developed, thanks to the now available traction fluids.

Jatco and NSK are improving their Extroid; the next generation is coaxial and so will be smaller, lighter and have a better efficiency.

Torotrak is optimizing its IVT. It seems that series 3e, under development, shall also be coaxial. An enthusiastic road test report, a tech description and an extensive photo gallery are on line under:

http://www.webnolimits.com/dovat/index.php?content=trk_en

http://www.webnolimits.com/dovat/index.php?content=gallery

Cheers
Aorangi

 

[evelrod]

My memory still tells me 'NSU' but it was in 1966, I think, and we HAVE discussed my 'memory' in these forums before LOL

I cannot argue the technical merits of a variable drive as the facts pretty well speak for themselves. What I can address is the lack , indeed the total lack, of enthusiam for the CVT as it is presented to the US automotive market today. Aside the aforementioned F-500 series plus an excursion into variable drive in a couple of dirt bikes (Rotak(?) or Bombardier I think???my famous memory again) in the 70's , the buying public are basically ignorant of the technology. (OK, I live where it does not snow for you snowmowatchamacallits)
The best I see for the future is a 'niche' market a la Mazda RX-7, assuming it is marketed as a 'performance' enhancing addition and not 'econo' related.
Bottom line is that I will not buy a 'new' anything strictly for economy sake. Generally, a good , cheap used car is far more cost effective than ANY new econo car.
If I am going to spend my hard earned cash on something , it is going to be something "nice"(read that as sporty, fast, big, safe, expensive or whatever suits you as an individual). I have been around a day or two and seen the auto industry try inovative technology and as I have observed, it seems to take about twenty years +/- for the "good stuff" to catch on (barring govt intervention).
I truly do not believe I am alone in my opinion as a member of the buying public.

The F-1 tests were done a few years back(possibly Williams at Silverstone but I am probably wrong on that, too) and the PR release stated that the CVT car was immidiately faster than the conventional gearbox car. I vaguely remember the article and as I recall it was very pro CVT. The prohibition of the drive in current racecars is blamed on 'big brother'. In this instance, its the FIA. I have my doubts.

Believe only half of what you see and none of what you hear

Rod

 

[drwebb]

Febuary Auto Engr. Intl. has a write-up. Said it was smooth overall, but clutch engagement was jerky and it was noisy. What is the fluid life on such transmissions?

Nissan has deployed a CVT with a V-6 in the Murano sport-wagon, so torque carrying is going up. And the Audi 6-speed double clutch has been enthusiastically received by the press (see the above magazine, among others). Incidentally I note the Torotrak also has a double clutch. Reports I've heard indicate the 6-speed DC shifting is transparent, it can use fill-for-life ATF, and some data claims superior mileage gains to CVTs and even manuals. It is also technologically more familiar to the auto companies.

Lots of neat designs going on in the transmission business these days. It'll be interesting to see how it all shakes out.

 

[aorangi]

Rod,
I guess the average driver doesn't know and doesn't care what the working principles of an auto tranny are. As long as it works as he expects, he's satisfied. A CVT or an IVT can be electronically programmed to behave just like a conventional torque converter automatic or switched at will to imitate a powershift double clutch cogbox such as the new Audi & VW DSG, but with any number of discrete ratios.
About the new 240 hp / 350 Nm Nissan Murano equipped with the latest version (30 mm width push plates with 2x12 pre-bend rings) of the Van Doorne belt CVT, from:

http://www.canadiandriver.com/articles/tl/03murano.htm

"On the road, the CVT does its job well. When reserve power is needed - passing an eighteen-wheeler, for example - it's delivered promptly and smoothly. Behind the wheel, most people probably couldn't tell the difference between the Murano's CVT and a well-engineered conventional gearbox, and Nissan will not be highlighting the CVT in their marketing strategy. According to Hugh Wickham, if people want more details about the CVT, they will be happy to provide them, but there are no plans to make a big deal about it. Incidentally, Nissan has been working with CVT transmissions for over 30 years, and sells about 180,000 vehicles a year with this technology.....mainly in Asia."

And Van Doorne Transmissie guys say the increased their production of steel push belt from 590.000 units in 2001 towards 1.200.000 in 2002, along with an increase in application range.
But they'll probably soon have tough time coping with the competition of chains and other CVT concepts.

Drwebb, I read the article you refer to. The journalist is obviously incompetent and inaccurate. He tells of a 400 Nm 5.4 liters V8 while it's a 475 Nm one. He equals the Torotrak IVT with a 10 speed tranny, as if the number 10 was equivalent to infinity! He seems to doubt that an IVT doesn’t need a starting device… He claims there are jerks when shifting from low, split power operation to high unsplit operation, showing he doesn't even know this shift is done at synchronous speed of the clutches and so cannot produce any jerks. He speaks of some noise from the transmission hydraulics.

Perhaps I'm deaf as well as are the 3 other guys who were aboard the Torotrak prototype, but we didn't hear any noise originating from the transmission. We also failed to perceive the shifts from low to high, but we are probably to harsh to be sensitive to jerks and shocks. Yeah… it's tough getting old!
Oh, by the way, Shell and Torotrak say the transmission "traction" fluid is filled for life.

Cheers
Aorangi

 

[JayMaechtlen]

Personally, I'd love to have a vehicle that ALWAYS has the right ratio available!

When hauling a trailer, and you want gear 1.5, or gear 3.5, etc!

when just cruising around town, and need to 'nail' the gas to get in front of (or out of the way of) someone- lots of time the downshift of an automatic may be too slow, too much, or not enough!

Driving I-10 over the pass between Indio and the River, where the car won't quite pull in top gear, but 3rd is a bit low (for 75MPH)
maybe a 5-speed or 6-speed would do it- but all of those require the designer to forecast the future!

With a CVT, you just HAVE ANY RATIO YOU NEED!

I think I like it :-D

cheers
Jay Jay Maechtlen

 

[Bicknoller]

Quote from Dave Szczupak, head of Ford Powertrain Operations worldwide:

"I'm personally very impressed with the technology and have the support of my colleagues who can see the tangible benefits that the transmission delivers. The technology has stood up to significant interrogation from my team and major tier 1 transmission suppliers. The prototypes drive very well and I like what I see with the latest developments. Dick Elsy (new CEO at Torotrak)clearly brings a new focus to Torotrak and, as a car man, is well placed to take the transmission through to market launch."

The tier 1 referred to is probably ZF who are licensees of Torotrak and have a joint venture with Ford which manufactures CVTs. Torotrak are thought to be developing a fully engineered production prototype IVT in partnership with Equos who are the research group of Aisin. The unit is expected to be a co-axial configuration and is expected to be substantially smaller and lighter than the development versions evaluated by Ford, GM and BMW.

Aisin are said to be the largest suppliers of automatic transmissions to GM. Szczupak's quote and the involvement of Equos/Aisin suggests that Ford and GM might both be involved in continuing development of IVT.

Torotrak said in a recent statement "Analysis by one of the tier 1 transmission suppliers shows that an IVT equipped vehicle would be a bonnet length ahead of a similar vehicle with a 6AT after four seconds of full throttle acceleration".

We live in interesting times!

 

[skyline69]

I have held shares in Torotrak from the start as this is the first CVT/IVT that I think may exactly be accepted by the buying public and I agree that it will have to make it's way into either a luxury model or a performance model vehicle and be very high profile if 'Joe Public' is to invest there hard earned money in it. I just hope the manufacturers give it a chance and don't do a Toyota on it!

 

[kih]

The current CVT transmission for GM is currently selling approx. 70,000 units a year, it has been a slow start but we expect it to increase to 250,000 transmissions per year.

This is for 3 applications and 1 SUV, the major problem with any CVT is the durabity issues, and getting acceptance. However with the CVT transmission with very simple changes it is possible to dictate the number of gears,from 5 or 6 to 20 for example, so if the public are still unsure about this product maybe this is a way forward, this may also assist in the high pressure required for the High torque engines.

 

[JayMaechtlen]

"is possible to dictate the number of gears,from 5 or 6 to 20 for example"

You mean, make it sound like a conventional automatic transmission, even though it could be much better?
hmmm...

Jay Maechtlen