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. The seven-speed dual-clutch transmission 7DCT300 is a transmission of third generation with Smart Actuation. The dual-clutch transmission for mid and front transverse applications sets standards in efficiency. Due to Smart Actuation, the transmission requires only as much energy as a light bulb.
The dual clutch transmission (DCT), also referred to as a double- or twin-clutch transmission, combines the best of both manual and automatic transmissions into a hybrid that requires no input from the driver to shift gears, provides smooth and fast shifting, and operates more efficiently than either a manual or an automatic transmission. Its unique configuration is known as a semi-automatic transmission. It uses two separate clutches, one which engages even numbered gears in the transmission while the other engages the odd numbered gears. While one gear, third gear for example, is engaged, the clutch has the next gear, possibly fourth gear if the driver is speeding up, ready to go so it can instantly switch from third to fourth without losing any of the engine's power and without requiring the driver to press down the clutch pedal as he would need to in a manual transmission car.
Since the car's driver isn't required to press a clutch pedal to shift gears, it would seem the dual clutch transmission is automatic. Yet it is actually semi-automatic. Electro-hydraulic fluid is used to engage and disengage the clutches. This fluid forces the clutch disk against the flywheel of the engine and the power spins the car's wheels. When the car slows, sensors send less fluid to the clutch and it disengages because the fluid's force is not strong enough to hold it against the flywheel.
Two clutches make the dual clutch transmission possible. While one gear is engaged, the clutch prepares to switch to the gear on the opposite clutch. Since one clutch holds the odd numbered gears and the other the even numbers, the clutches constantly switch back and forth and the transition from one to another happens so quickly the driver never feels the car change gears.
Advantages of the dual clutch transmission include more efficient performance and faster shifting speeds. Since the next gear is already ready to switch into, the change occurs almost instantly and the shift is smooth. No engine power is lost, as it is in automatic transmissions using torque converters to engage and disengage the engine. The torque converter is similar in principle to the electro-hydraulic fluid, but loses some of the power from the engine when engaging and disengaging.
Disadvantages of the dual clutch transmission include its high cost and the complexity of its parts. Cars utilizing this type of transmission cost more and repairs take more effort due to the extra parts and how they are aligned with one another. With more parts, there are more problems that can arise.
(Updated on December 31, 2019)
The dual clutch transmission (DCT) is referred to by several names including double-clutch transmission and twin-clutch transmission.
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
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.
Dual Clutch Transmission Dct
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.
Dual Clutch Transmission Gm
Conclusion
Dual Clutch Transmission Fluid
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.