Team-BHP - Ford PowerShift Dual-Clutch Transmission (DCT) - A Technical Overview
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-   -   Ford PowerShift Dual-Clutch Transmission (DCT) - A Technical Overview (https://www.team-bhp.com/forum/technical-stuff/168683-ford-powershift-dual-clutch-transmission-dct-technical-overview-2.html)

Quote:

Originally Posted by arunphilip (Post 3812847)
Previously, there was confusion over whether the 'sealed for life' constituted a warranty also; but none of the documentation indicated this was a warranty. However, a member has pointed out on either the Figo or Aspire thread that he'd seen material referring to a 10 year warranty (couldn't locate that post, sorry!). I've not seen any other confirmation other than this one item.

Quote:

Originally Posted by i74js (Post 3812955)
The 10 year warranty was offered in Fiesta. Though even this warranty was not able to bring in fresh customers.

There is no news of such warranty on the new Aspire / Figo.

Here is the post that refers to Aspire AT DCT gearbox warranty. The quote is taken directly from the Ford Media release during the Aspire launch:
http://www.team-bhp.com/forum/indian...ml#post3779085

Here is the press release for the new Figo which also specifically mentions the 10 year 1 Lakh Km warranty on the automatic gearbox. http://www.india.ford.com/about/medi...=1249173475333

Excellent thread arunphilip! Thanks for this! I always wanted to know the basic thing about this gearbox and this seems be the right thread. If I think of a typical manual gearbox setup, the engine sits on one side of the clutch and gearbox on the other. But in case of DCT how does is the engine connected to two clutches at the same time? Due to these multiple concentric shafts, I am unable to visualize it. Where does the crankshart connect to the clutch? Any diagramatic explanation would be highly helpful.

Very informative thread! :thumbs up I was of the impression that DCT too would be electro-hydraulic in operation but surprised to find that its not.

Another advantage apart from quick shifts of the DSG's electro-hydraulic unit is that hydraulic unit can in theory offer more clamping force for the clutch pack compared to a reduction gear based electro-mechanical unit. In practise with a DSG remap the clamping force is (can be) increased.

Mitsubishi EVO X has a Getrag twin wet clutch transmission which Mitsubishi calls SST. This Getrag is an electro-hydraulic unit utilising hydraulic pressure for shifting and holding clutch plates.

Quote:

Originally Posted by arunphilip (Post 3812926)
particularly since wet clutches require oil lines from the engine.

The transmission oil, oil pump. transmission oil filter and transmission oil cooler are separate from the engine oil circuit.

It's a fantastic piece of technology.
Even I've read that ford gives a 10 year/ 240000 km warranty on the gearbox. I think this warranty was there even in the 2011 fiesta.

The good thing about this transmission is we get good fuel efficiency and close to nil torque loss compared to conventional fluid coupling AT. How ever at extreme spirited driving and/or jump start and stop in bumper to bumper city traffic, the electronics get confused in adapting to driving habit and as a result clutch weakens soon and would start shuddering in 2nd and 3rd gears.

This being a dry system, what are the possibilities that it will suffer same problems of DSQ200.
I already saw potential of overheating being mentioned in the original post. Bangalore traffic will be real test for this.
If this box also suffers same failures as the famed VW dry box, the warranty will be quite handy.

Excellent thread arunphilip. Your efforts are much appreciated. Thanks.

In India, where the average ambient surface temperature, on a hot sunny day, in traffic conditions, can easily be 50 degree Celsius plus, I wonder if a dry clutch setup would be reliable in the long run. Especially in the start-stop-start-stop conditions. Guess we'll only know, once, Ford starts churning out volumes of this transmission. Hope it doesn't end up being another DSG.

Quote:

Originally Posted by RWD (Post 3813640)
Excellent thread arunphilip. Your efforts are much appreciated. Thanks.

In India, where the average ambient surface temperature, on a hot sunny day, in traffic conditions, can easily be 50 degree Celsius plus, I wonder if a dry clutch setup would be reliable in the long run. Especially in the start-stop-start-stop conditions. Guess we'll only know, once, Ford starts churning out volumes of this transmission. Hope it doesn't end up being another DSG.

As an owner of EcoSport AT, I pray not. Ford sells the same gearbox in countries like Brazil, which can get quite hot and humid. I heard Sao Paolo is almost at hot and muggy as Chennai in summer (February, for them in the southern hemisphere). So it should be well tested by now. But, you never know.

Fantastic Information
Thanks for sharing.

The 1D representation of the gear engagement and the working phenomenon has given me good insight to the working of a dual clutch system.clap:

Just a question: Does any car have Dual mass flywheel and Dual Clutch together??
or this is some weird combination of me, as I know their requirements by cars are completely different.

Very informative thread and thanks for sharing.

Hopefully this will be the Dual Clutch for the masses given its affordable positioning (in its Figo avtar)

Quote:

Originally Posted by Sankar (Post 3812990)
Very informative thread! :thumbs up I was of the impression that DCT too would be electro-hydraulic in operation but surprised to find that its not.

Another advantage apart from quick shifts of the DSG's electro-hydraulic unit is that hydraulic unit can in theory offer more clamping force for the clutch pack compared to a reduction gear based electro-mechanical unit. In practise with a DSG remap the clamping force is (can be) increased.

Higher clamping force so that car can handle more engine torque?

Quote:

Originally Posted by Mpower (Post 3814385)
Higher clamping force so that car can handle more engine torque?

Yes, to mitigate the chances of clutch slip with high engine output setup. Not done normally.

Very nice thread and great insights. I have a DCT Fiesta Petrol AT and love driving it in the city and even highways.

Few questions for the general community of interested readers here:

- I presume that these boxes are ECU controlled (and maybe even a separate ECU for the box), so is it possible for after market remaps of the boxes for a shift pattern that one would prefer? Any examples or such work done abroad?
I know of a TSB that Ford had done for the DCT in Fiesta for the clutch shudder/jerkiness in stop-go traffic. I had got it done and the DCT box behaved very differently after that TSB.

- These boxes will also have been tuned with the engine combo (So, my assumption is that the DCT box would be tuned differently for Aspire/Figo/Fiesta/Ecosport). If this assumption is correct, then any mod we do to engine (let's say FFE etc etc), will that impact the way DCT behaves/shifts for that particular car?

- Fiesta didn't come with that manual +/- shifter buttons on the DCT. Can these be retrofitted?

Quote:

Originally Posted by khan_sultan (Post 3814660)
- I presume that these boxes are ECU controlled (and maybe even a separate ECU for the box), so is it possible for after market remaps of the boxes for a shift pattern that one would prefer? Any examples or such work done abroad?

Yes there is a separate TCU (transmission control unit) for the box. Custom shift patterns should be possible to implement by an experienced and knowledgeable TCU remapper. HPA motorsports might be one such company abroad.

http://www.hpamotorsports.com/dsgtuning.html

Quote:

Originally Posted by khan_sultan (Post 3814660)
- I presume that these boxes are ECU controlled (and maybe even a separate ECU for the box), so is it possible for after market remaps of the boxes for a shift pattern that one would prefer? Any examples or such work done abroad?

As Sankar has mentioned, the gearbox has its own control logic called the transmission control module (TCM). I've covered this in the second post (which talks about the various components). Getrag has designed this gearbox to be quite independent of the engine, so while the TCM takes in various inputs from the ECU, it then interprets that input and applies its own internal logic to then perform gear changes (i.e. the TCM is only loosely coupled to the ECU).

Sankar has also pointed out tuning options for VAG's DSG series of gearboxes. However, I'm not aware of any tuning options for these low-torque DCTs for Ford. Higher performance PowerShift transmissions might have tuning options (such as the 7DCI700 used in various BMWs), but probably not the lower torque DCT we get in India.

Quote:

Originally Posted by khan_sultan (Post 3814660)
I know of a TSB that Ford had done for the DCT in Fiesta for the clutch shudder/jerkiness in stop-go traffic. I had got it done and the DCT box behaved very differently after that TSB.

Thank you for that feedback, good to hear that. It will also reassure potential buyers of the DCT :thumbs up

Quote:

Originally Posted by khan_sultan (Post 3814660)
- These boxes will also have been tuned with the engine combo. If this assumption is correct, then any mod we do to engine (let's say FFE etc etc), will that impact the way DCT behaves/shifts for that particular car?

The TCM/gearbox are loosely coupled to the engine, and the TCM takes as its input the engine speed (crank RPM) and engine torque (among other inputs), and drives its logic accordingly. In that respect, the gearbox will adapt to any changes in power output, particularly for 'stage 1' mods like FFE, CAI. However, if the power output has changed in terms of 'pattern' (e.g. peak torque coming in sooner), then the TCM would benefit even more from being reprogrammed to be aware of these changes. This is because factors like the upshift point are all based on the stock engine's performance, and you might realize even better performance in tuning the TCM accordingly. Then again, if you're looking at mods higher than stage 1, you probably shouldn't be targeting the PowerShift transmission - all reviewers acknowledge that it is a commuter transmission, not a performance one :)

Specific to India, I'd be curious just how extensively and how well the TCM has been adapted to the characteristics of the 1.5 TiVCT box we get here. Remember that this 1.5 TiVCT box is specific to India, and is derived from the international 1.6 TiVCT (those humourously inclined might joke that that the 100cc that was removed also took all the goodness out of that engine!)

Quote:

Originally Posted by khan_sultan (Post 3814660)
- Fiesta didn't come with that manual +/- shifter buttons on the DCT. Can these be retrofitted?

It might not be that simple. The Fiesta not only came without the SelectShift +/- buttons, it also came with a subtly different gearbox - it has a low range (L) mode, instead of the Sport (S) mode that comes in the EcoSport and Figo siblings. At best, you might be looking at replacing the entire TCM to be able to use the +/- buttons. A replacement TCM costs approximately $800 in the US.

Wonderful article.

I have a couple of questions though.
In the figure below, how is the torque being transmitted in the sloping section of the blue line?

Quote:

Originally Posted by arunphilip (Post 3812535)

Quote:

Originally Posted by arunphilip (Post 3812847)
Manufacturers use dry-clutches in low-torque applications,

What are the thought processes behind choosing a dry clutch vs a wet clutch?

Regards
Sutripta


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