中英文文献翻译—双离合变速器

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Dual clutch transmission

From Wikipedia, the free encyclopedia

A dual clutch transmission, commonly abbreviated to hoop DCT (sometimes informally referred to as a twin-clutch gearbox, double clutch transmission, or similar variations thereof), is a differing type of semi-automatic or automated manual automotive transmission. It utilises two separate clutches for odd and even gear sets. It can fundamentally be described as two separate manual transmissions (with their respective clutches) contained within one housing, and working as one unit. They are usually operated in a fully automatic mode, and many also have the ability to allow the driver to manually shift gears, albeit still carried out by the transmission's electro-hydraulics.

This type of transmission was invented by Frenchman Adolphe Kégresse just prior to World War II but he never developed a working model. The first actual DCTs arrived from Porsche in-house development, for Porsche racing cars in the 1980s, when computers to control the transmission became compact enough: the Porsche Doppelkupplungsgetriebe (English: dual clutch gearbox) (PDK) used in the Porsche 956 and 962 Le Mans race cars from 1983, and the Audi Sport Quattro S1 rally car.

A dual clutch transmission eliminates the torque converter as used in conventional epicyclic-geared automatic transmissions. Instead, dual clutch transmissions that are currently on the market primarily use two oil-bathed wet multi-plate clutches, similar to the clutches used in most motorcycles, though dry clutch versions are also available.

The first series production road car to be fitted with a DCT was the 2003 V olkswagen Golf Mk4 R32.

As of 2009, the largest number of sales of DCTs in Western Europe are by various marques of the German V olkswagen Group, though this is anticipated to lessen as other transmission makers and vehicle manufacturers make DCTs available in series production automobiles. In 2010, on BMW Canada's website for the 3 Series Coupe, it is described both as a 7-speed double clutch transmission and as a 7-speed automatic transmission. It is actually a dual clutch semi-automatic.

In DCTs where the two clutches are arranged concentrically, the larger outer clutch drives the odd numbered gears, whilst the smaller inner clutch drives the even numbered gears. Shifts can be accomplished without interrupting torque distribution to the driven roadwheels, by

applying the engine's torque to one clutch at the same time as it is being disconnected from the other clutch. Since alternate gear ratios can pre-select an odd gear on one gear shaft whilst the vehicle is being driven in an even gear, (and vice versa), DCTs are able to shift more quickly than other cars equipped with single-clutch automated-manual transmissions (AMTs), a.k.a. single-clutch semi-automatics. Also, with a DCT, shifts can be made more smoothly than with an AMT, making a DCT more suitable for conventional road cars.

Characteristic of Dual clutch gearbox

Advantages:

1. Compared with the traditional planetary gear type automatic gearbox fuel economy is more advantageous to the ascension can reduce fuel consumption about 15 percent

2. During the shift, almost no damage

3. When high-grade gear is already in preparation condition, rise against extremely fast, achieve astonishing 8 millisecond

4. No matter what is running mode accelerator or condition, can reach 600 shift time (at least from the odd block to millisecond odd block, or even block drop from even when it took about block, for 900 milliseconds, for example from the first five block to 3 block)

Faults:

1. The electric control system and hydraulic system due to the existence of gearbox efficiency, double clutch than traditional manual gearbox still used to deliver big torque, especially the wet dual clutch gearbox is even more so

2. Dual clutch gearbox cost is higher, the development of precision and complex double clutch, resulting in higher prices

3. When need to switch gears in preparation condition, not shift time relatively long, in some cases even more than 1 second

4. Dual clutch gearbox, compared with the traditional manual gearbox heavier

5. Dual clutch the biggest transfer torque transmission on the low side, restrain the engine of space

6. Early dual clutch gearbox reliability poor

7. Gearbox lubricant need according to factories require change regularly, and replacement costs is not cheap