21 replies to this topic

[Grumbles]

I'll kick it off with George Constantinesco's inertial transmission - in effect, a mechanical torque converter. George was probably most famous for his mechanism for synchronising the firing of a machine gun through a propellor, but he invented other interesting stuff as well..

Edited by Grumbles, 21 March 2011 - 08:29.

[mariner]

The Issigonis gearless mini with just a torque converter and reverse. It relied on a wide torque band engine of bigger than usual size plus high multiplication converter. BL let Issigonis play with it for years with a 1.5 litre engine in a Mini but it got nowhere.

Then there is the Perbury variable disc, and from railways,the Fell multi engine transmission.

Maybe the sight of whirling gears does things to people?

[24gerrard]

The Issigonis gearless mini with just a torque converter and reverse. It relied on a wide torque band engine of bigger than usual size plus high multiplication converter. BL let Issigonis play with it for years with a 1.5 litre engine in a Mini but it got nowhere.

Then there is the Perbury variable disc, and from railways,the Fell multi engine transmission.

Maybe the sight of whirling gears does things to people?

Hahaha probably.

I built a modified AP auto Mini for Leyland with no torque converter and electronic shift just before Leyland went bust.
They considered it for a production prototype. It was far more efficient than the Issgonis power train.

The Perbury is a form of toloroidal constantly or totaly variable transmission.
All CVT and TVT transmissions suffer from the need for high energy input to compress the drive components.
Discs in fluid with toloroidal and variable diameter cones with the Van Doorne type.
I have an ongoing disagreement with Patrick Head on the energy efficient suitability of any CVT, that goes back to his CVT Williams that was banned after Coulfhard tested it.
I notice that Williams have gone away from the Perbury toloroidal drive in their flywheel KERS system, replacing it with the far more efficient induction electric flywheel.
I suggested a combination of batteries and a small flywheel of this type for this years regulations in F1 but the teams have all elected to use just battery storage.
This is mainly a result of the weight distribution benefits of batteries and the fixed weight distribution.
As always F1 controls development with regulations that prevent innovation. Other than in irelevent aero that is.

Modern so called seamless gearboxes are simply marketing hype.
They have higher torque loss in their geartrains than single layshaft boxes and all the fancy quick shift devices cannot exceed a good driver with a stick shift on a dog ring box.

[24gerrard]

I'll kick it off with George Constantinesco's inertial transmission - in effect, a mechanical torque converter. George was probably most famous for his mechanism for synchronising the firing of a machine gun through a propellor, but he invented other interesting stuff as well..

One of many interesting and clever mechanical ways to avoid the use of gears.
However, it again suffers from high mechanical losses and vibration.

[gruntguru]

As far as CVT's go, one of the most common examples is the electric transmission as used in Diesel-Electric locomotives. Series hybrid cars use them too, with some electrical storage thrown in for good measure.

[24gerrard]

As far as CVT's go, one of the most common examples is the electric transmission as used in Diesel-Electric locomotives. Series hybrid cars use them too, with some electrical storage thrown in for good measure.

I think you are refering to 'shunt' gearboxes that are in effect multi segment electric motor/generators.
The CVT aspect is because of the flat torque curve acentuated by the low speed brushed DC design and complemented by the constantly variable shift between shunt fazes.

I have a patented ESERU that also uses multi planetary sets with CVT electric shift, it is either a KERS unit or a Hybrid unit but can also be described as a shunt transmission.

[Grumbles]

The Issigonis gearless mini with just a torque converter and reverse. It relied on a wide torque band engine of bigger than usual size plus high multiplication converter. BL let Issigonis play with it for years with a 1.5 litre engine in a Mini but it got nowhere.

Then there is the Perbury variable disc, and from railways,the Fell multi engine transmission.

Maybe the sight of whirling gears does things to people?

I hadn't heard of the Fell, so looked it up. It scores bonus points for the odd way that it regulates engine torque, ie. by adjusting the speed of the auxiliary engines driving the roots blowers that feed the main engines.

[Grumbles]

One of many interesting and clever mechanical ways to avoid the use of gears.
However, it again suffers from high mechanical losses and vibration.

Provided you had multiple sprags working through overlapping arcs, would the torsional vibration really be any worse than from say a four cylinder engine? And assuming negligible sprag slippage I'd have thought the losses would be fairly light. They couldn't have been too bad to get 100mpg at 38mph in the mid twenties.
On the downside I can't imagine the sprags lasting long, and there'd be no engine braking..

[24gerrard]

Provided you had multiple sprags working through overlapping arcs, would the torsional vibration really be any worse than from say a four cylinder engine? And assuming negligible sprag slippage I'd have thought the losses would be fairly light. They couldn't have been too bad to get 100mpg at 38mph in the mid twenties.
On the downside I can't imagine the sprags lasting long, and there'd be no engine braking..

I would be dubious about the figure of 100mpg at 38mph.
However, it is not unusual for vehicles of this era to achieve high mpg figures in tightly focused operating envelopes.
In fact a direct drive high diff ratio set up with no gearbox would almost certainly give even better figures.
To judge a vehicles (or powertrains) fuel efficiency needs a lot more factors in a full operations cycle.
I also believe that this system would seriously limit the engines rpm.

[Greg Locock]

Wow, when I started at BL a single speed Mini was parked in the gas turbine's car park, along with a lot of more interesting cars. I thought it was the 1.8 engine.

[PJGD]

I have never had the opportunity to drive a car with the Cotal "electric" transmission, although plenty of high-end French cars used it (come to think of it, that would be why I have not experienced it).

Anyone out there any experience with it?

PJGD

[Kelpiecross]

I'll kick it off with George Constantinesco's inertial transmission - in effect, a mechanical torque converter. George was probably most famous for his mechanism for synchronising the firing of a machine gun through a propellor, but he invented other interesting stuff as well..

Grumbles - I was pleased to see this topic come up as it is one of my main interests.

As far as I know, there has never been (even in theory) a genuine "positive engagement" continuously variable gear system. It is slightly difficult to define such a system exactly but I mean one that basically acts like a "conventional" gear system except that the speed ratio between input and output (and output and input - it must work in both directions) - can be varied through an infinite range. Additional requirements are that no "continuous" elements like friction, hydraulics, ratchets or variable speed electric motors are allowed.

Ever since the days of Da Vinci (maybe even before?) this has been a Holy Grail of inventors - but it has never been done.

Why would this be? Is there some natural law of nature or physics that precludes it being done? Is it yet to be done? Is it possible?

[gruntguru]

I suppose gears, chains etc have ratios defined by division of integers since there is no such thing as a fraction of a tooth. Even the Constantinesco device has stepped ratios if you use positive enngagement ratchets as opposed to friction pawls.

[Kelpiecross]

I suppose gears, chains etc have ratios defined by division of integers since there is no such thing as a fraction of a tooth. Even the Constantinesco device has stepped ratios if you use positive enngagement ratchets as opposed to friction pawls.

Grunt - what you say is one explanation you see for the lack of variable gear systems - usually expressed as "Gears are, by their nature, digital - a variable gear system is, by its nature, analogue - so the two things are incompatible". But these are just words, not really an explanation for the lack of variable gear systems.

[24gerrard]

The prius gear system is an interesting combination of CVT and epicyclic well worth a look at.
It is half way to my ESERU. electric shift energy recovery unit.
The Prius uses two electric motors and an ic engine and balances the torque inputs and outputs through the epicyclic.
Unfortunately, as in all CVTs the energy needed to control it outways the benefits and a good diesel can exceed the efficiency.
I should unerline this fact. All CVT transmissions require energy to operate their control systems and this negates any efficiency gains.

[cheapracer]

I'll kick it off with George Constantinesco's ....

Wasn't he on "Seinfeld"?

[cheapracer]

The Issigonis gearless mini with just a torque converter and reverse. It relied on a wide torque band engine of bigger than usual size plus high multiplication converter. BL let Issigonis play with it for years with a 1.5 litre engine in a Mini but it got nowhere.

Then there is the Perbury variable disc,

The first Honda Civic's slushmatic was a single gear. Yes it had 'Low' as well (another seperate gear) but that was manually selected (rarely needed) otherwise relied purely on it's 4:1 (?) torque converter whether in Low or Drive.

Nissan have a production Perbury disc transmission as standard in some "Japan only" models I was quite surprised to discover. May not be suitable for Westerner's heavy right foot I presume.

Edited by cheapracer, 28 March 2011 - 20:16.

[Grumbles]

Wasn't he on "Seinfeld"?

That's him. I believe he (along with his father) was also instrumental in the development of Kramer's "Man-sierre" or man-bra..

[ozdude]

In another life I owned a mini moke that I fitted with a 1300 (1275) Morris motor and AP auto box. Aside from having to cut and shut the suspension towers from a minimatic subframe to fit the moke, the install was straightforward. With some minimal head and port work, and a LCB (long centre branch) exhaust the beast went exceptionally well. Stopping was something else!

The AP box was surprisingly easy to recondition once I tracked down the parts. I found the auto box nearly as quick to change as a manual and a whole lot more convenient in Sydney traffic.

[cheapracer]

I seem to recall John Harvey's McLaren M6 Repco V8 had a clutched auto in it, must look into it as he won the Oz Sports Car Championship with it around 1970.

A few drag boys have had clutched auto's too over the years.

Mazda had a 13B Rotary with a manual 5 speed but a torque converter in between the motor and clutch, it was either for easier city driving in Japan or pollution requirements I guess as it was Japan spec only.

[24gerrard]

http://oi37.tinypic.com/s3hnhd.jpg

Some of the transmission development work I did in the 70s.
The AP box is a very useful unit for competition.

[cheapracer]

Yeah, thanks Canuck