Here at the Hoffman Auto Group we pride ourselves on offering a wide variety of vehicles to suit every driving need. Whether you are looking for an old school standard stick shift or a fully automatic driving machine, you will find it here. Perhaps, however, you are looking for something in between? Maybe you would like a car that allows you to control your ride like a standard transmission but with the convenience of an automatic. Say Hello to the Dual Clutch Transmission.
What is A Dual Clutch Transmission?
The dual-clutch transmission (DCT), also known as the Direct Shift Gearbox is an automated transmission that was designed to enhance the shifting experience by eliminating the lag inherent in a manual transmission.
In a conventional manual gearbox, when a driver wants to change gears, she presses down the clutch pedal which disconnects the engine from the gearbox and interrupts the power flow to the transmission. Then the driver uses the stick shift to select a new gear, a process that involves moving a toothed collar from one gear wheel to another. Once the new gear is engaged, the driver releases the clutch pedal, which re-connects the engine to the gearbox and transmits power to the wheels.
The twin-clutch transmission is essentially two separate transmissions with a pair of clutches between them. One transmission provides odd-numbered speeds (ie first, third and fifth gear), the other provides even-numbered speeds (second, fourth and sixth). When the car starts out, the “odd” gearbox is in first gear and the “even” gearbox is already in second gear. When the car shifts into second, the odd gearbox automatically moves into third in anticipation of the next gear move. And so on, up the gear chain.
We talked with John Pighetti at Hoffman Used Car SuperStore and asked why this is an advantage for drivers? He explained that “unlike a standard vehicle, there is no interruption of power to the transmission. The gears are like a step ladder: when you are driving in first, second gear is already in place. When it’s time to change gears, the transmission simply uses the clutches to switch from the odd gearbox to the even, for a near-instant change to the next gear. The shift between gears is much faster and smoother.”
What is its History?
The man who invented the dual-clutch gearbox was Adolphe Kégresse, a pioneer in automotive engineering. He conceived the idea in 1939, but poor business circumstances prevented further development.
Both Audi and Porsche picked up on the dual-clutch concept, although its initial use was limited to racecars. In 1986, a Porsche 962 won the Monza 1000 Kilometer World Sports Prototype Championship race — the first win for a car equipped with semi-automatic paddle-shifted transmission. Audi also made history in 1985 when a Sport quattro S1 rally car equipped with dual-clutch transmission won the Pikes Peak hill climb, a race up the 4,300-meter-high mountain.
How do you drive one?
Twin-clutch equipped cars do not have a clutch pedal; the clutch is engaged and disengaged automatically. In Drive mode, the twin-clutch transmission operates like a regular automatic and shifts to higher gears early in order to minimize engine noise and maximize fuel economy. Cars with a Sport mode hold the lower gears longer to keep the engine in its powerband. Sport mode also provides more aggressive downshifts with less accelerator pedal pressure, and in some cars, including most Audis, causes the car to react more aggressively to the accelerator pedal.
Most twin-clutch transmissions have a manual mode which allows manual shifting via buttons, steering wheel paddles or by moving the gear stick. The transmission will follow the driver’s commands unless, John tells us, “the selected gear is inappropriate and would over-rev the engine (i.e. commanding first gear while driving 80 MPH).”
Why Choose One?
The primary advantage of the dual clutch transmissions is that it combines the driving characteristics of a manual transmission with the convenience of an automatic. The top reasons for choosing a DCT are “enhanced performance, traction and speed. The DCT offers the most dynamic acceleration of any vehicle on the market because instant gear shifts mean faster acceleration. It offers also smoother acceleration by eliminating the shift shock that accompanies gearshifts in manual transmissions. Best of all, it affords drivers the luxury of choosing whether they prefer to control the shifting or let the computer do all of the work,” says John.
But it doesn’t stop there John says: “Because there are more gears and no interruption of the power from the engine to the transmission, DCTs offer dramatically improved fuel economy.”
The DCT in the end is an ideal candidate for a driver who wants to have an engaging manual like driving experience when they want it, and a comfortable automatic transmission for more mundane driving. “It is,” John says, “a phenomenal choice.”