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The Automatic transmission: A brief history

Posted May 10th 2012 6:00PM


The manual transmission is not long for this world, much to the consternation of the "driving aficionado." As evidence, consider that the take rate for manual transmissions for all Lamborghini models - among the most extreme super-sports cars on the planet, mind you - is a measly 1 to 2 per cent.

For the mathematically challenged, this means that 98 to 99 per cent of Lamborghini customers are opting for the company's e-gear semi-automatic transmission over the traditional triple-pedal set-up. And the e-gear isn't even one of the best transmissions in the business.

All is not lost, though, because the latest generation of automatics can, in some cases, provide an equal measure of driving pleasure. Here's a rundown of the different kind of automatics, including those that will no doubt be propelling us forward in the future.

Set your shifter to Drive after the jump.
Related GalleryAutomatic Transmissions
Subaru LineartronicManumaticAudi Sport Quattro Twin ClutchHydra-MaticLeonardo Da Vinci's CVT

Fully automatic transmissions: Just select drive, she said

While opinions vary as to who created the first truly workable automatic transmission - claims date back to the 1890s - the GM Hydramatic, which was first introduced in 1939, is generally considered the first successful mass-produced automatic and one of the most important innovations in automotive history.

Compared to now, the early automatic transmission was a much simpler innovation: four forward gears plus reverse. When parking a first-generation Hydramatic-equipped car, drivers would have to shut off the engine and then select reverse in order to lock the transmission; there was no "park" setting.

Although the Hydramatic was a 4-speed, subsequent automatics included 2- and 3-speeds and, later, various-speed transmissions with overdrive settings for better efficiency when driving at a steady rate. Over the years, more gears were added to increase efficiency and ensure the proper gear was in place for those times when quick acceleration was needed.

While "basic" automatic transmissions allow the driver to select (and hold) a lower gear - when climbing a steep hill or descending a treacherous one, for example - their defining characteristic is that they don't have a separate gear lever position to let you manually shift from one gear to the next.

Manumatics: The start of something better

One of the first successful "automated manual" transmissions to be used in a production car appeared in 1989 as an option on the Porsche 911. Dubbed the Tiptronic, this transmission acted as a typical automatic but also allowed the driver to manually select gears using the gear lever or buttons on the steering wheel.

When the Tiptronic first appeared, it became the word used by many people to describe similar transmissions from other car makers. While those licensing the Porsche system did rightfully call theirs "tiptronic," other manufacturers had their own trade names in place.

The word "tiptronic" has since nearly vanished from our common lexicon, as has the word "manumatic"; both have been replaced in the collective consciousness by the term "semi-automatic transmission." This is understandable given that the manumatic and semi-automatic achieve the same outcome, despite the former using a torque converter and the latter employing electronics to ease gear changes.

Semi-automatic transmissions: Six speeds of one, half-a-dozen of the other

Again, the semi-automatic is a transmission that can manage all gear changes for the driver or allow the driver to shift manually using a gear lever, shift buttons or shift paddles.

In some cases, the semi-automatic retains ultimate control of gear selection even in manual mode - for example, when the engine reaches its redline and the driver hasn't reacted quickly enough. Depending on the manufacturer's choice of transmission, though, the engine could also simply bounce off the rev limiter until the driver selects a higher gear. Some semi-automatics also direct the car to start in second gear rather than first gear, even when in manual mode.

Although earlier versions existed, the semi-automatic transmission was thrust into the spotlight by the Ferrari 640, a Formula One car that was campaigned during the 1989 season. In the hands of Nigel Mansell, the 640 won its very first race, setting off a wave of development that ultimately saw the manual transmission disappear from Grand Prix racing in 1996 (seeing a trend yet?).

These days, the semi-automatic is the dominant transmission type for vehicles in North America, guiding gear selection on everything from minivans to super-sports cars. Some of these transmissions are simply incredible; the Superfast semi-automatic once used on the Ferrari F430 Scuderia, for example, could reportedly shift gears in just 60 milliseconds.

Continuously variable transmissions: Infinitely automatic

The continuously variable transmission (CVT) is an automatic with a difference. Rather than having a set number of gears, the CVT has a wider span of gears available, thereby ensuring the engine is always running at peak power or peak efficiency at all times.

There are a number of different designs for the CVT, with the most common design employing a pulley system driven by either belts or metal chains to achieve infinite variability between lowest and highest gear.

The CVT has been around for a long time - the first one was sketched out by Leonardo da Vinci over 500 years ago. Furthermore, this transmission type has been used in snowmobiles, tractors and industrial equipment for decades now. While the first car to use a CVT appeared in 1923, it has really only gained traction, so to speak, over the last decade.

Due to the fact that the CVT can shift gears without any noticeable interruption in momentum, it has had some difficulty in resonating with the general public. As a result, some CVTs have been calibrated so that they mimic the gear-shifting sensation found in other automatic transmissions. A number of CVTs have also been given manual shift functionality - operated by paddle shifters in some cases - to bring back that same sensation.

Dual-clutch transmissions: Double your pleasure

The latest trend to hit the transmission scene, the dual-clutch automatic - also known as the twin-clutch or double-clutch, depending on the manufacturer - was, like the semi-automatic and the CVT, invented decades ago but has only recently become popular.

The dual-clutch is so named because it's essentially two manual transmissions, each with their own clutch, working together as one unit. Like the semi-automatic, the dual-clutch can control gear shifts automatically or through input from the driver using a manual shift mode.

The big advantage of the dual-clutch is that gears are pre-selected at all times - one clutch handles the odd-numbered gears, the other the even ones, so upshifts or downshifts are conducted without interrupting torque to the driven wheels. In other words, gear shifts are faster, smoother and more efficient than in a conventional automatic transmission.

The dual-clutch transmission was successful in racing, initially with the Porsche 956 Le Mans-type car in 1983 and the Audi Sport Quattro S1 rally car the following year. The first commercial application of the dual-clutch transmission - labeled the Direct-Shift Gearbox (DSG) - appeared in the Volkswagen Golf R32 in 2003.

Since then, the dual-clutch has appeared in numerous cars, particularly those with serious performance credentials such as the Nissan GT-R, Mitsubishi Evolution X, Ferrari 458 Italia, Porsche 911 and Bugatti Veyron. In terms of driver involvement and genuine bang for your buck, the dual-clutch is the only automatic transmission to rival the good, old-fashioned manual.

News Source: Evergeek


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