| A Touch Of The CVTs | ||
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by Ross Finlay (14 Apr 04) He recalled, in pitiless detail, that I had stopped astride a line, switched off the engine (thus causing a marshal to make vigorous hand signals which translated into "This isn't the finish line, you idiot!"), started up again, fumbled for reverse and backed away to the next manoeuvre - all because I thought you couldn't move the DAF Variomatic system from forward to reverse while keeping the engine running. At this remove, I have no idea whether his remarks constitute (a) a monstrous and unforgivable slur on my appreciation of the technicalities of Variomatic, (b) a plain statement of fact, or (c) an acknowledgement that the 55 Marathon was an odd little affair to drive. At least it wasn't lumbered with the model name of the original DAF, the Daffodil. While Audi's very sophisticated Multitronic strikes me as one of the best transmissions on the market, the original DAF system - like many of its successors - did have some quirky characteristics. What tickled me most was that if you floored the throttle the engine revs rose immediately, and you could hold them there while the continuously variable belt drive varied itself continuously until the road speed caught up with the engine. Big snag, though. Many an overtaking manoeuvre would be called off because the evidence of the ears didn't match the evidence of the eyes. With a steady engine note, there were no sound effects of acceleration, although the landscape was whizzing past at an ever-faster rate. It was sometimes just impossible to accept that there really was enough room, out on the far side of the road, to pass a Reliant three-wheeler and tuck back in again before the oncoming Scammell. An Old Idea Revived Electronically controlled CVTs are much more subtle now, of course. It's a curious thing, though, that transmissions of this kind go back a long way before the Van Doorne brothers' original mid-1950s DAF Daffodil. In fact, engineers have been working for more than a century on "stepless" transmissions without any individual gears. At a time when changing gear with manual transmissions was such a potentially laborious, noisy and terrifying procedure that most car owners employed chauffeurs to drive them about, the first make known to work with this kind of pulley-operated transmission was the Weber from Switzerland. Built by a company based in Uster, east of Zürich, whose main business was textile machinery, the Weber was in production from the turn of the last century until 1906. Several hundred cars were built before production petered out. A different system with basically the same stepless effect was friction drive, in which the variation in ratios came about as a disc which took the drive to the wheels moved across the face of a disc driven by the engine. It appeared first of all a little earlier even than the Weber system, in a long-gone French make called the Tenting - which sounds better pronounced in French, as in the name of the inventor Monsieur Tenting. From France, the friction drive notion spread to Germany and was taken up for the Weiss cars from Berlin, then moved across the Channel, where several British makes followed on. Their cars were usually inexpensive and low on power output, and the one which lasted longest was the GWK cyclecar, not least because of its splendid advertising slogan "A Gear for Every Gradient". GWK was a Thames Valley company which started in the unlikely rural surroundings of Datchet and then moved to Maidenhead. Grice, the "G" of GWK, was also involved in another friction drive car, lumbered with just about the most un-marketable name in the history of motoring. What kind of PR could you have done with a product called Unit No. 1? |
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