The History of the Dual Clutch Transmission – Jalopnik

In the beginning, man invented the engine. Now the engine was switchless and isolated. And as inventors hovered over the surface of their workshops, they moved on the crankshaft and said: “Let there be a transmission that brings the power from the engine to the drive shaft.” They added a link and saw that it was good. Then people wanted to drive really fast without taking their hands off the wheel, so we got dual-clutch transmissions (DCTs), launch control and Ferrari 812 Superfasts that could hit 60 miles per hour in under three seconds.

That’s a bit of an oversimplification, but the point is that transferring constant rotational energy to a wheel that sometimes doesn’t need to move is crucial. Clutches disconnect engines from gearboxes to allow for such downtime, but operating a single clutch and an H-pattern manual transmission without synchronization takes skill, finesse and elbow grease. Inventors and engineers in the early days of automobiles went to great lengths to create easy-to-operate gearboxes, such as the Sturtevant automatic transmission of the early 20th century and the pre-selector gearbox of the 1930s. But DCTs are in a different universe of complexity.

DCTs work by giving the even-numbered gears a clutch and the odd-numbered gears a separate clutch, and then letting the hydraulics and electronics control the flow of power. The result is smooth, uninterrupted acceleration and better fuel economy without the high skill and effort ceiling. And even though the electronic controls we take for granted didn’t exist in the early 20th century, inventors were still trying to make the concept work.

In 1935, French inventor Adolphe Kégresse patented a bona fide “dual clutch transmission.” He found manual transmissions too difficult to use and wanted a simpler, smoother alternative. In 1939, Kégresse fitted a dual-clutch prototype called Autoserve to a Citroën Traction Avant, but it was never put into production. His invention was also patented in America in 1946 (US2543412A), probably by his son, also named Adolphe, as the patent states it was filed by “Adolphe Valentin Kégresse, administrator of the estate of Adolphe Kégresse, deceased.” The eldest Kégresse had died in 1943.

Borg-Warner patented its “double countershaft transmission” in 1949 (US2599801A), which was intended to “provide a means of operating a transmission that applies an uninterrupted flow of power from the engine through the transmission during changes in speed.” In addition to the two friction clutches, the Borg-Warner design used five dog clutches (positive clutches) to engage gears.

Speaking of the 1960s, this is where we come to Porsche. In 1964, the company started looking into dual-clutch technology and wanted to integrate such a gearbox into the Porsche 911. The electronic controls were still not smart enough, even though Jack Kilby had invented microchips in 1958. Porsche has therefore been wise to make the 911 only with a manual gearbox forever. We’re kidding – unfortunately, the company instead offered its four-speed Torque Converter Sportomatic as a 911 option, which did the impossible and made Porsche 911s boring.

But Porsche is still Porsche, and if there’s cool technology to be discovered, it will be. So in 1979, the automaker reconsidered the dual-clutch concept for its 956 Group C race car. In 1981, the dual clutch was tested to provide the driver with smooth, uninterrupted power delivery – a must for the high-performance turbo cars to avoid a boost drop. Porsche called it the barely pronounceable ‘Doppelkupplungsgetriebe’, which was fortunately shortened to PDK.

There were two buttons to switch. The top one shifted up and the bottom one shifted down. Finally, drivers could keep both hands on the steering wheel while changing gears in corners. Porsche also tested PDKs in a 924 and a 944, but used the push/pull lever instead of buttons. As you can see, there are no 924s or 944s running around with PDKs like this, so it never made it into production. But one of the people who got to test the cars was the legendary Ferdinand Piëch, then head of technical development at Audi.

Piëch was stunned and immediately rushed back to Audi and told the team that they had to put this transmission in the Group B Audi S1 ​​right now. In November 1985, a PDK-equipped Audi Quattro S1 crushed competitors with a 19-minute lead at the Semperit Rally Austria.

In 2003, DCTs returned in some form – this time for the masses, when Europe got the Volkswagen Golf R32 with the first production dual-clutch, followed shortly after by the Audi TT. Let’s see: Who was CEO of Volkswagen in the early 2000s? Ah, Ferdinand Piëch, that makes sense. Volkswagen called its DCT the “DSG”, which stands for DirektSchaltGetriebe. Thank goodness German manufacturers like acronyms, because that’s a mouthful. S-Tronic is Audi’s term. Audi, does the S stand for “Schnelles und Automatisches Schalten über Schaltwippen und Zwei Kupplungen” (fast and automatic shifting via paddle shifters and two clutches)?

And so, before the manual transmission was a protected species, DCTs exploded in popularity. This is especially true for performance cars where consistent power delivery delivered phenomenal acceleration figures. That’s why we have DCTs in the R35 Nissan GT-R, Audi R8, internal combustion Porsches since 2008 and the glorious Bugatti Veyron.

Another threat to DCTs is electrification, as most electric vehicles only use direct drive, with the Porsche Taycan and its two-speed transmission being a rare exception. Enthusiasts are also starting to miss stick shifting, regardless of acceleration times, and long for that mechanical connection that was lost with, as Jeremy Clarkson once quipped, flappy paddles. But while DCTs may have surged in popularity, they are far from extinct.

Bee Porschethe PDK remains, and in 2022 more than 75% of 911 buyers opted for that gearbox. Christian Hauck, head of Alternative Drives at Porsche, told Hagerty: “A very important thing for us is that we have the ability to change the gear ratios on every single gear that we have in the gearbox, so that we can really tailor it in the perfect way to each car that we apply the PDK transmission to.” Dual clutches are indeed technologically marvelous, and whatever their weaknesses, they are certainly not CVTs.