Classifying a "Clutchless Manual" Transmission
 

So, the crystal ball isn't working well when it comes to predicting the future of the FE Team Challenge :o

At any rate, that's why we have polls right?

The question is: How to you classify a Sequential Manual Gearbox for purposes of the competition? For those unfamiliar, it's basically a transmission that has an electronic clutch (no pedal) and sometimes an "Automatic" feature.

"Manual" is pretty simple: clutch pedal, gear throw.
"Automatic" is more complex but simple: some have "Manumatic" shift-gates, but it still has an automatic transmission hooked to it, generally with a torque converter.
The "SMG" is what? Here's a few Wikipedia entries that I looked at, but figured I'd pitch it to the group for more info:


Electrohydraulic Manual Transmission
Sequential Manual Gearbox
Semi-Automatic Transmission
(also known as "Clutchless Manual", "Automated Manual", etc.).

Since I'm not an expert on transmissions by any stretch, I've posted the poll for more insight.

If you vote, all I ask is that you have an understanding about how it works, and explain why you voted as such...

Thanks!

The Commish

Where's the poll?

I think manual because the computer is acting as the clutch and rev matching and it doesnt operate like an auto in any other sense. FE should be closer to an equivalent manual than having the losses associated with an auto.

delay
 

Hmm, it looks like the poll posts shortly after the "explanation post"...

What is automatic?
 

If the car in question has no clutch pedal and has a fully automatic mode featuring fully automated upshifts and downshifts, how much more automatic can it be? Surely not my idea of a conventional manual transmission.

I vote automatic.

RH77 -

I vote automatic because I think it is only providing human decision making/control over the gear being used at speed "X". Since the driver doesn't do the "work" of shifting gears, the automatic components that add load to the engine still have to be there, right?

CarloSW2

I voted Automatic. My reasoning is that the manual mode is really nothing more than an automatic, where, in theory, the system allows the driver to over ride the computer or some other system which would control the shifting. I believe that they generally have a torque converter, for engaging and effectively they are a dressed up Automatic, masquarading as a Manual. I also agree that if they have a full automatic mode, they ought to be considered an Automatic.

If it has a bunch of whirly fluid and a torque converter, it's an automatic. If it is a computer controlled manual trans, it is a manual.

Just my opinion for purposes of the FE Team Challenge.

To me the acid test is can the driver shift gears when he wants to. If has control when it shifts then it a manual whether it has a clutch or not. Maybe a smart driver should chime in and tell us exactly how it works.

It it has a manual and a auto mode then the driver would have to use only the auto mode to be concidered an automatic, which I guess would be on the honor system.

Way I understand the system I say manual.

For mileage purposes, I'd say the question is whether you can shift it into and out of neutral (or de-clutch it) easily and safely.

DING DING DING!

Just because it shifts gears for you doesnt mean it should be classified as an Auto.

The question is about the new generation of transmissions that have a clutch and are basically a manual transmision save the computer rev matches so the driver does not have to do anything. Most of these sytems will let you choose when to shift as well.

We are not talking about the same systems were its a full auto with a "manu shift" feature...

Just posting this from an engineering standpoint. Since we are looking at this for effeciency, I would think it depends on whether the transmission has a torque converter or not. A torque converter is a fluid coupling and is one of the big things responsible for the decreased FE of an automatic-equipped car. The slip in a torque converter generates heat and is why automatics generally need a fluid cooler or at least a large oil pan to dissipate heat while manuals do not. That heat sent to the cooler is your lost FE.

I'm voting automatic - because:

The 'EPA' figures will be lower for an 'automatic', so if you drive a 5-speed manual, or an automatic, you will 'start' at 0% above EPA anyway.

BUT... an automatic will mean that P&G is either impossible or risky, engine-off coasting again is impossible or risky. This means that an Auto car will result in less hypermiling opportunities.

I think an auto is a car where you don't have a clutch or a gearshift, meaning you can't do exactly what you want with the clutch and the gearstick. So, whatever technology is behind the auto box, it is still an auto box (whether 'classical' auto, CVT with torque convertor, CVT without torque convertor, (all of which could be seen as a 'clutchless manual'.

The 'classical' auto boxes use loads of clutches all controlled by electrical/mechanical means anyway, so they could be considered a clutchless manual too :) (where the clutch isn't seen by the driver that is)

I'm with Bill/Houston and bbgobie and others: if it has a torque converter with its associated losses then it's an automatic. If it has a computer controlled clutch then it's effectively a standard.

However - if the computer-controlled clutch type tranny doesn't allow engine-off neutral coast as well as engine-on neutral coast and bump start and going into neutral at any time, then it's not a "standard" for our purposes.

brucepick -

Yes yes yes.

CarloSW2

Neutral on coast - check, dont see how that can be a problem.
Engine off coast, and bump starting...
Hmmm... Someone walk into a Volkswagen dealer, ask to test drive the new Golf and settle this for us!!

If you can get a video of the salespersons face when you turn off the engine while coasting and bump start it... well, lets just say that would be priceless...

Classification thus far
 

So, we probably need clarification on the following:

There are several types of "Clutchless Manual" Transmissions...

In this case, can you coast in a "Neutral" state?
Is it possible to turn the engine off while in motion?

Some do not have a torque converter like a "Slap-Shift" gear selector-type transmission.

I looked up EPA data on such transmissions:

The 2007 BMW M5 comes in either 6-speed manual, or "SMG". The data designator for the SMG is "Auto(S7)" -- translation "Automatic -- Sequential Gearing, 7-Speeds". It also notes that it has a "6-Mode CLKUP". 6 Different modes can be selected (probably automatic and 5-modes from "soft shift" to "racing shift". CLKUP = Converter (torque), Lock-Up Type.

Perhaps this sheds some light on this particular vehicle. For specific vehicle purposes, perhaps data like this could be presented?

Commish

It appears to me that all sequential shift transmissions listed (S4, S5, S6, S7) in the EPA data link submitted by rh77 are considered to be automatic transmissions.


From Ford Motor Co. Automotive Glossary:

Manual transmission, A transmission in which a driver selects gears by means of a hand-operated gearshift and a foot-operated clutch (also known as a "stick shift").

Great, a Tie
 

Well, it looks like we have a 50/50 tie from the poll. Using the info posted, I should have a decision posted soon...

The Commish

Decision: Automatic
 

The ruling is that SMG or similar gearboxes (sequential or automated manual gearboxes with an electronic clutch) falls into the "Automatic" category for the competition.

Why?

• The Poll resulted in a tie, requiring a tie-breaker
• The EPA classifies them as Automatics -- and we use their numbers for the basis of establishing baseline FE.
• Shifting into Neutral does not occur traditionally (some designs require stopping or downshifting sequentially).
• EOC may not be possible.
• The design is essentially a manual transmission -- but, with the addition of electronic controls, the definition changes.
• The spirit of the competition team's vehicle make-up is to ensure variety (the different design satisfies this aim).

If there are any concerns, please let me know. Thanks, and best FE...

The Commish

I am a little late on this one. But I voted ? manual ? last week.... hummm ... don't tell CO ZX2 ... he will kill me !

The problem is : it is not black or white -- automatic vs manual -- but the new auto trans are somewhere in between. In North america, when we think automatic we refer to the american auto trans ( you know all that whirly fluid and a torque converter said Bill in Houston). They are practical but inefficient. But in Europe they had different automatic for some time. I remember in the early sixties, these Citro?n DS , semi-automatic by a stick at the steering wheel, and the Renault R-8 full-auto push button type . They were both without a clutch pedal, with an electric gear change manual type transmission. Today, on-board computer make the gear change much easier. They had no choice in Europe at that time since their car engines had much less power than american gas guzzlers.

I thought last week, for purposes of FE team challenge, the best would be to forget about the necessity of an ? automatic team member ?, or else ask for the real american automatic transmission before it is extinct.... I might be wrong, but I beleive in the near future, we won't see these any more, and all these sequentials, CVT and clutchless manuals will be the norm.

Well a few words about my car, a Smart fortwo CDI dsl turbo 800 cc auto-manual trans.

It is a sequential 6 speeds with full auto mode and a manual mode ( no clutch pedal of course). In full-auto, the computer changes the gears electrically (clutch and gears) at a pre-establish rpm depending upon load. In ? manual ? , the driver order the computer to change gears at will. But there are drawbacks that let me think it is 75% manual. These restrict the hypermiling opportunities:

1- The computer automatically downshift ( in manual mode) at around 1230 RPM, much too high for FE purposes. The engine could go down to 1000 without lugging ( like on the vw tdi at 1000 rpm in 5th).

2- We cannot turn off the engine when coasting and if we do so, we must go to a complete stop to restart.

3- So, no pulse & glide possible. ( but luckily a nice 0 fuel on compression).

4- We can put trans. in neutral while coasting, but on re-entering the gear, the computer choose the one gear like if it was in automatic mode ( lower gear).

5- No possible bump start in regular driving.

Rh 77, the best system I have seen was started by one of your favorite car companines back in 1955.

Citroen's Citromatic (Citromatique) was a conventional manual gearbox with clutch controled by the cars high pressure system, with control of shifting done by hand (with a small shifter the size of a pencil) that controlled a spool valve, this controlled fluid flow to the cylinders on the manual gearbox, and a low pressure pump sensed engine speed and would work the slave cylinder. A WONDERFUL system to drive, crisp and concise shifts, and if you had the gas pedal to the floor, the system would fling it back at you.

So you had to shift, let up on the gas, but no clutch pedal.

Here is more on the system:

https://www.citroen.mb.ca/tech/DStech...ion/index.html

Here is how to start the system (with the gear selector, prevents starting in gear, but you could also lock the system for push starts and crank starts):

https://www.youtube.com/watch?v=y-kcPwVperM

Note how he also sets the ignition before the manual choke.

Neat system, never duplicated, both simple and complex at the same time.

Antoine: I am a little late on this one. But I voted ? manual ? last week.... hummm ... don't tell CO ZX2 ... he will kill me !

CO ZX2:

Welcome to Team GasMisers5.

Antoine, you're an honest guy. We will get along just fine. I haven't shot at anybody since last Wednesday ;). After all, this is the Old West.

Citro?n Citromatique
 

Good to see you back Spule 4 :thumbup:

I came across Citro?n's design during my research on the subject. Good link to the video, BTW (it looks like a little arcing from the coil :eek: ). Cool car, though -- it's been around for a while - kinda surprised the concept didn't take off sooner.

I'm still waiting for that C4 Diesel-Hybrid...
:D

Perhaps reliability was a concern -- I know BMW had quite the issue with their SMGs when first introduced a few years ago.

RH77

Citromatic was a pain when not right. Lurchy car. Forget valet parking.....

It was also a Rube Goldberg way to make an automatic. The Traction Avant was to have a full automatic, several were developed, none worked, more money, Andre went bust, and Michelin moved in for control.....

So, Citroen did the next best thing, and made a manual box fully automatic.

Now, this is not to be confused with the C-Matic that went into the CX and GS/A. These had true torque converters. Citroen also used the BW35 automatic for the last of the non-US D cars and for US SMs.

Another neat car with (I think) electric clutch and manual shift was the NSU Ro80. I think it was an electric clutch as there was a sensor switch on the shifter that would dis-engage the clutch the second your hand hit it. Kind of a pain, and a bit odd when you drove it (I have not driven one in nearly 20 years).

So, with the advances in torque converters and automatic gearbox technology, the Citromatic transmission was never really duplicated in its form, even by Citroen who had all that extra hydrualics in the cars already, so that should tell you something.......

EDIT: The Citroen 2CV cars also had an optional centrifical clutch in the 425cc motored cars.

SAAB used this on their "Saxomat" optioned cars in the early 60's, probably the same device, or built under license. No pedal, an electric switch in the change lever operating a solenoid... Since so much early SAAB was copied from Germany (the first prototypes in 1949 used DKW engines, my V4 engine was built by Ford of Germany, even now the 9'3 is basically a rebadged Opel) it wouldn't surprise me if the two systems were the same.
But the NSU was later so maybe the SAAB was a failure first.
"Ve are Cherman. Ve vill learn from our OWN mistakes!"

Here is a good video of Citromatique starting and shifting, on a uber rare Jubilee none the less!

https://www.youtube.com/watch?v=DZk6nHxE2TE

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