Dual Clutch Transmission



(Updated on December 31, 2019)

  1. Dual Clutch Transmission Hyundai
  2. Dual Clutch Transmission Ford
  3. Dual Clutch Transmission Fluid
  4. Dual Clutch Transmission Fluid
  5. Dual Clutch Transmission Motorcycles

The dual clutch transmission (DCT) is referred to by several names including double-clutch transmission and twin-clutch transmission.

  • Dual Clutch Transmission. With our automatic DCTs, one clutch is engaged with the current gear while sensors predict whether the next gear change will be an upshift or downshift. The second clutch prepares the next gear ratio for instant engagement with a negligible loss of torque. Our 8-Speed DCT includes a torque converter to smooth low-speed.
  • Dual clutch transmissions, or DCTs, have become a popular transmission option for vehicle designers as they combine the gear efficiency of a manual, with the.

DCT stands for Dual Clutch Transmission, but that alone doesn’t fully explain it. A DCT is a type of Automated Manual Transmission (AMT) that has two clutches instead of just one. They are gaining.

A regular manual transmission vehicle would use one clutch and a clutch pedal. The dual clutch transmission uses two separate clutches with no clutch pedal.

Since there is no clutch pedal, the clutches are controlled through hydraulics and advanced computer electronics. This is the same technology that you’d find in some of today’s newer automatic transmission vehicles.

Top 5 Advantages of a Dual Clutch Transmission

Below are the top 5 advantages of using a vehicle with a dual clutch transmission.

1) Faster Acceleration

Many people who have driven double clutch transmission vehicles have said love how the car accelerates. This is due to the gears being able to change almost instantly and allowing you to accelerate in far less time than the same vehicle with a manual or automatic transmission instead.

You can upshift in just a few milliseconds, creating a dynamic and smooth acceleration experience.

2) No Shift Shock

Both manual transmission and regular automatic transmission vehicles will often generate a jolt each time a gear is changed, especially if accelerating heavily. This jolt is called shift shock and it can be quite annoying.

Picture the occupants of a tuner car as the driver accelerates quickly to get on the freeway. With each hard gear shift, each persons’ head slams forward and back.

Fortunately, double clutch vehicles do not have this shift shock when gears are changed. The shift changes are hardly noticeably.

3) Fuel Economy

There is no interruption when energy flows to the transmission from the engine. Because of this, the fuel economy of the vehicle becomes greatly improved. With the enhanced fuel economy, you will also have better fuel efficiency too.

4) No Clutch Pedal

Many people who prefer manual transmissions for their fuel economy and faster acceleration will love dual clutch automatic transmissions since you don’t have to worry about operating a clutch pedal. It’s a fact that a dual clutch will shift quicker than even the best short throw manual shifter.

You’ll have more room in the foot well without the third pedal making driving for long periods more comfortable. Of course, purists will still prefer a clutch pedal and there’s nothing wrong with that.

5) Driver Options

Wet dual clutch transmission

Drivers can even select whether they want the central computer to control the shifting or if they want to use manual paddle shifters or another semi-manual mode for a more involved driving experience.

Most dual clutch vehicles also offer different driving modes at the push of a button which affect the vehicle’s shift points. Set it to sport mode to hold gears longer resulting in better acceleration, economy mode to prioritize taller gears for better fuel economy, or other modes in between. The decision is yours.

Top 5 Disadvantages of a Dual Clutch Transmission

Dual clutch transmissions are definitely not perfect though. Below are the top 5 disadvantages of this technology

1) Higher Vehicle Cost

You can’t expect to find a dual clutch vehicle to be priced the same as an economy car. It costs manufacturers a lot more money to produce these vehicles on the assembly line. This makes the final vehicle a lot more expensive to consumers.

So, if you’re counting your dollars closely, then you might be turned off by this vehicle’s price. Many vehicle models offer more than one type of available transmission so you can easily see the price difference and whether it’s worth it.

2) Maintenance and Repair Cost

Follow the manufacturer’s maintenance schedule is important for any car but it’s critical for those with a DCT. For instance, Audi recommends changing the gear oil in their DCT vehicles every 40,000 miles. This is not a cheap service and not something you’ll often with regular transmissions at that interval.

If something does go wrong with a dual clutch transmission, the repair or replacement cost can be ridiculously high and not all auto repair shops may be able to do the work. This is why proper maintenance is so important.

3) Low Selection

Due to the expense of integrating a dual clutch transmission system into a vehicle, many car manufacturers are electing not to use them. That is why most twin clutch transmission systems are found in high-performance cars and luxury cars.

Since most people are not in the market for a high-performance car, so their options are going to be limited here.

4) Not the Same Driving Experience as a Manual

While DCT transmissions have surpassed the fuel efficiency and shifting speed of manual transmissions, they simply don’t provide the same fun driving experience as stick shifts. For some this doesn’t matter, but nothing beats the connectivity a driver has to the road by shifting their own gears.

Sure you may have some type of manual shift mode override (usually in the form of paddle shifters), but ask any driving purist and they’ll tell you it’s just not the same.

5) Slow to Motion

While some dual clutch transmissions are better than others, you may experience a slight lag when going from a static position to a moving position. Once you get moving though, the instantaneous shifting of a DCT takes over.

Conclusion

The dual clutch transmission takes the best features of an automatic and manual and places them into one vehicle. If you don’t mind the higher cost, it is worth considering purchasing your next vehicle with one.

Belt and pulleys of a Van Doorne transmission
Variomatic transmission and rear axle. The larger green drums on the left contain the vacuum mechanism that controls the variable pulleys. The rear wheels are driven by separate belts, eliminating the need for a transaxle.

Variomatic is the continuously variable transmission (CVT) of the Dutch car manufacturer DAF, originally developed by Hub van Doorne.[1] It is a stepless, fully-automatic transmission, consisting of a V-shaped drive-belt, and two pulleys, each of two cones, whose effective diameter can be changed so that the 'V' belt runs nearer the spindle or nearer the rim, depending on the separation of the cones. These are synchronized so that the belt always remains at the same optimal tension.

History[edit]

The Variomatic was the first commercially successful CVT (as opposed to shifting between separate gears). In theory, this always produces the optimum torque. The Variomatic was introduced by DAF in 1958, also putting an automatic gearbox in the Netherlands for the first time. The Variomatic was introduced on the DAF 600.

Efficiency[edit]

Because most of the time the engine runs at its most economical speed, the fuel consumption of this car was acceptable, although the fuel efficiency of any mechanical CVT is about 70% (then) to 75% now (Bosch) (now).[citation needed]

Reversing[edit]

Because the system does not have separate gears, but one (continuously shifting) gear and a separate 'reverse mode' (as opposed to reverse gear), the transmission works in reverse as well, giving it the interesting side effect that one can drive back as fast as forwards. As a result, in the former Dutch annual backward driving world championship, the DAFs had to be put in a separate competition because no other car could keep up. Thus, these very cheap and simple cars were the 'formula one' in this competition.

Multitronic[edit]

Manual transmission remains dominant in Europe. When DAF was acquired by Volvo in 1974, the Variomatic patents were transferred to a company called VDT (Van Doorne Transmissie), later acquired by Bosch in 1995. VDT continued the development of the CVT and introduced a push-belt system in the Ford Fiesta and Fiat Uno. Audi reintroduced an improved version of the Variomatic in 2000 under the name multitronic. This system uses a metal belt and has an effectively unlimited number of gears, switching between them without noticeable shocks. These metal drive belts are the most important part of CVT. There are three factories producing these belts, the Bosch factories in Tilburg the Netherlands, Ho Chi Minh City Vietnam, and San Luis Potosí, Mexico. It is used in over 40 car models, even with expensive brands like Mercedes-Benz.

Operation[edit]

Gear ratio[edit]

The final drive has two pulleys with moveable conical drums. The distance between the drums is controlled by the engine vacuum in the inlet manifold and engine RPM, through centrifugal weights inside the drums. Between the two pulleys runs a drive belt. As a result of the change in the distance of the conical drums in both pulleys, the diameters and so also the reduction ratio changes continuously.[2]

Differential[edit]

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With the DAF 600 - 55, each rear wheel was propelled individually by a pair of conical drums and drive belt with the effect of a limited-slip differential: if a drive wheel on slippery road revs up, the other wheel can still transfer the full torque. This results in unusually good traction characteristics, which were also a reason for the successes of the DAFs in rallies. There were several disadvantages that accompanied the lack of a true differential gear. Although each belt could settle (independent of the other) into its optimum position, thus allowing for wheel speed variation, the system was slow to operate and depended on the pulleys being turned. This led to rapid tire wear and placed stress on other transmission components. Snapped drive shafts were common. Low-speed handling in icy conditions was interesting as the system tended to drive the car forward against the influence of the steered wheels. Later cars, the 46, 66, and Volvo variants were fitted with a differentially geared axle. A version with a differential was developed by Williams in the 1993 Williams FW15C CVT Formula One car,[3][4][5] but it was banned before being raced. In testing there were problems with the heat production.[6]

Motorscooters[edit]

The Variomatic is also used in today's motorscooters. It has been a standard part of all common scooters since 1985, and several companies such as Malossi, Polini, Doppler, and Stage6 are offering tuning clutches and variomatic for most common 50, 70 and 125 cc scooters.

Dual Clutch Transmission Hyundai

Steel link belts[edit]

The modern CVT works according to the same principle of split pulleys allowing infinitely variable gear ratios. Rather than the pulled rubber drive belts as originally used by DAF, the modern transmission is made more durable by the use of steel link belts that are pushed by their pulleys. This improvement was pioneered by Fiat, Ford, and Van Doorne in the Netherlands from the late 1970s.[7] The gearbox is also under electronic control.

One version that incorporates the switch from rubber to steel belts was called the Transmatic.[7]

Availability[edit]

DAF's Van Doorne's Transmissie is still operating (as of November 2015) in Tilburg, Netherlands. It changed affiliations from the DAF group to Bosch in 1995.[8]

Honda dual clutch transmission

Dual Clutch Transmission Ford

The CVT is available from brands such as Audi, Honda, BMW Mini, and Subaru.[citation needed]Tata Motors from India intended to use a Variomatic transmission in its $2500 Nano.[9][citation needed] The Nissan Primera is offered with this transmission.

Dual Clutch Transmission Fluid

Dual Clutch Transmission

External links[edit]

Notes[edit]

Dual Clutch Transmission Fluid

  1. ^'Transmissions drove Hub van Doorne's innovative spirit', February 2009, autonews.com
  2. ^'Belt Drive Shifts Dutch Economy Car.'Popular Mechanics, December 1959, pp. 140-142.
  3. ^'Image: williamscvt.jpg, (600 × 386 px)'. 8w.forix.com. Retrieved 2015-09-02.
  4. ^'DAF passenger cars'. Ritzsite.demon.nl. Retrieved 2009-10-03.
  5. ^Per Hansen (2007-04-24). 'Formula One with Automatic transmission'. YouTube. Retrieved 2009-10-03.
  6. ^Keith Collantine (2007-05-03). 'Banned! Continuously Variable Transmission (CVT) | F1 Fanatic - The Formula 1 Blog'. F1 Fanatic. Retrieved 2009-10-03.
  7. ^ ab'Gearless transmission - steel pulleys make it automatic'Popular Science, July 1976, pp. 57.
  8. ^'Case Study: Keeping pace with the popularity of continuously variable transmission'. Siemens.com. 2012. Retrieved 2015-11-03.
  9. ^'Tata Motors seeks patent protection for Rs 1-lakh car'. Autoexpo.in. 2007-11-23. Retrieved 2009-10-03.

Dual Clutch Transmission Motorcycles

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