Volkswagen Direct Shift Gearbox

Alan impressed us all with his demonstration model of Volkswagen DSG (Direct Shift Gearbox): a 6-speed and reverse, computer controlled dual clutch transmission.

It features an over-centre spring-loaded clutch switching mechanism, a dual clutch using large axle (hollow) and tri-flat parts to split the drive into the constant mesh gearbox, 50-tooth contrate gear synchronizer assemblies and series connected inter-axle and front axle differentials, bevel gear rear axle drive output.

Gear changing and clutch switching is effected by five hobby servos operated from a servo driver board (printed circuit).

The dual clutch principle is to serve the odd numbered gears with one clutch and the even numbered gears served by the second clutch, facilitating rapid and smooth gear changing. In the DSG, clutch (1) serves 1st, 3rd, 5th & reverse; clutch (2): 2nd, 4th, & 6th — this pattern is reproduced in the model.

The model demonstrates the DSG gear changing strategies in pre-selecting the subsequent gear ratio then en-gaging it by switching clutches.

The servo driver board receives its commands from either of two forms of PC software. One is the driver board manufacturer’s scripted program; the other is by QBASIC programming code.

The latter enables the gear engagement and pre-selection events to be displayed on the computer screen. Either program enables any sequence of up-shifts, down-shifts and timing of in-gear/neutral events.

Comments

Congratulations Alan, that is brilliant.


Hello Alan, I have questions on the DSG of Volkwgagen, since everyone on the Internet comments that this mechanism is very bad. The reason why scares me because the GTI is expensive and I do not create what they say in Internet. They comment that one finishes very fast and that the composures are very expensive. What you think of this?


Seeing your model of the VW DSG made my day! I work for BorgWarner in the USA, near Chicago. My co-workers in Europe make the DualTronic controls and dual clutch module that are the heart of the DSG. Soon we will be launching this technology in the States. We’re very excited about the future of this type of transmission. There’s been a lot of enthusiast interest because it’s fun to drive, but more typical drivers will appreciate the fuel economy benefits of an automatic transmission that has no power-wasting torque converter. Extremely cool model, Alan. The over-center mechanism to handle the swap shift is a nice touch. Congratulations!


Excellent and outstanding work! I’m a Meccano enthusiast of those which seem to be less and less, since there are other competing educational toys that require less knolwledge, patience and planning, for which your project seems to raise the bar. I would be a very nice addition however, if you could post some other pictures with more detail on the synchros, the clutch, the synchromesh system, or perhaps even a more detailed assembly diagram. I’m sure most of your readers would agree that your model should be included as one of the hall of famers! . Again, congratulations.


Hi Jim. Thanks for your interest and complimentary comments. It’s a small world! I worked for Ricardo Inc. in Bellville Michigan for nine years as designer/manager, then retired in 2003 and returned to the UK. You may even know some Ricardo people? I know some ex Borg Warner people worked at Ricardo and previously with FFD Inc. ,where I started. My interest in the Meccano (Erector) hobby was re-kindled after a visit to the Detroit Auto show in ‘96, where I saw the underneath of an H1 Hummer, that started a whole new adventure into modelling the Hummer (see my models on the SELMEC website), also 4WD, IRS & IFS, limited slip diffs, and gearboxes etc. Shortly after our return to the UK I dicovered the DSG, and decided it was a ‘must’ to be modelled and combine my Meccano and computing hobbies. Thanks again, Regards, Alan.


Hello Andres. Thank you for your complimentary comments regarding my model DSG transmission. I am glad you found it interesting. I am aware that some readers may require more detail than contained in my in-depth article. The problem with providing this is that it requires a photographic record of every stage of the development of a model, regardless of whether it gets to be used in the final version. I am sorry to say that my enthusiasm to progress prevents this type of record keeping! This means that by the time a particular solution has been adopted, it is usually well embedded into the model and impossible to photograph in detail. However, in response to a previous enquiry, I did produce a free hand sketch of the dual clutch mechanism, which I will up-load to the website. Beyond this, I may record more photographic detail when the model is dismantled and add some of that content to the model gallery. Thanks again for your interest, Alan.


What are the advantages of this gearbox?


My knowledge and advantages of this gearbox are contained in my in-depth article about my model.


Hi Alan, I am impressed with your description of the DSG transmission and double clutch but, unfortunately I think I need more time to digest it since I am a novice at all this. My question is: I have a 2009 Audi TT 3.2 Quattro with the S-tronic DSG transmission. I believe I am having an issue with the transmission and wanted to get your thoughts; here is the scenario: On a steep hill I come to a complete stop, engage the hand brake; release foot brake; apply foot brake; put transmission into park; release foot brake; apply foot brake; release hand brake; place transmission into D; release foot brake; At this point the transmission (actually the AUID technician said it was the clutch) groans and the car starts to rollback and DOES NOT STOP until you accelerate. I don’t have this issue on a flat or slight incline and the service technician feels it is just the way the clutch and tranmission work together. I think they should always work the same regardless of the grade of incline. Your thoughts would be greatly appreciated since I am just starting this battle with Audi. Regards, Sue.


Hello Sue, I am not qualified to answer this question, but suggest it may be that at engine idle, there is insufficient clutch pressure to prevent rollback on steep grades. This would also apply to a vehicle equipped with a conventional automatic transmission with a hydrodynamic torque converter. The reason being that although such an AT produces residual torque (drag) at idle and in gear, if the up-grade is steep enough, the natural drag will be overcome by the rolling torque thus produced.


Hello! First of all my compliments for your astonishing project! Saying that it’s impressive is not enough! !! Anyway I have a few questions: 1) Is this project suitable for 6–10 year old children? 2) How long does it take a kid of that age to study and build the model? 3) Where can I buy the kit for this model? 4) How much does it cost?


Hello Leonardo, Thank you for your complimentary comments regarding my model. I will answer your questions in the order that you asked: 1) This is not a project suitable for normal 6–10 year olds. 2) I am a retired mechanical engineering designer and have had experience in designing gearboxes. This model took me 6–9 months of my spare time to research, design, develop, experiment and build. 3) It is not a kit model, it was designed and built from scratch using researched documentation and information using all and any available Meccano parts and non-Meccano electronic components. There are no instructions for making this model, although an advanced Meccano modeller could probably build one from the details and photographs in my article on the SELMEC website. The Meccano parts could be obtained from Dave Taylor, whose website is: www.meccanoman.com. The electronic components are available from Milford Instrumants at: www.milinst.co.uk. 4) The parts to make this model would cost between 1000 — 1500 if bought new. Regards, Alan Wenbourne.


Hi, I was looking at some clutch designs and so far I haven’t been able to deduce how gears are stopped in the planetary gear system, that is to say what is the mechanism used to control the planetary gear system? There doesn’t seem to be a good drawing or an explanation anywhere. I have found this old video http://www.youtube.com/watch? v=rQhzruw2Qh8 which is pretty awesome in it’s own way but they are using belts of some sort which seem to be nothing like what is actually used in a real car. Please help. Thanks.

Your e-mail address will not be displayed in public and will not be added to mailing lists. Please see our privacy policy for further information.