TotalEnergies special oil for dual clutch transmissions

14 czerwca 2023

The dual-clutch gearbox concept was first developed by the French engineer Adolphe Kégresse in 1939. However, this inventor lacked funds to realize his idea. Only in the 1950s, a British automotive company began to build the first gearboxes of this type based on two electromagnetic clutches, analog electronics, and coils! In the 1970s, Porsche began implementing dual-clutch transmissions for racing purposes, and in 2003 Volkswagen began mass-producing them for passenger cars. Now, amost all major brands offer them. In Seats, Skodas and Volkswagens it is called DSG. In Audi it is S tronic. Common names in cars of other brands are e.g., EDC, SST, DCT, TCT, DCT, PowerShift, Drivelogic or PDK. TotalEnergies reminds you of the basic principles of their operation and indicates what the oils intended for their service must have.

Breakthrough technology

When it seemed that nothing new would appear on the market of automatic transmissions, dual clutch transmissions (DCT - Dual Clutch Transmission) made their debut. Their design is based on the use of two clutches instead of one. The first clutch is responsible for the odd gear shaft, and the second clutch is responsible for the even gear shaft. The entire system is controlled by the gearbox controller. When the driver starts the engine, when the accelerator pedal is pressed, 1st gear is engaged with the first clutch and the second clutch is disengaged. When driving in 1st gear, the 2nd gear on the second shaft is synchronized. When a certain speed is reached, the controller disengages the first clutch and engages the second, enabling driving in 2nd gear. When driving in 2nd gear, the 3rd gear on the first shaft is already synchronized and ready to be engaged by the first clutch. The pattern repeats until top gear. This gearbox solution enables a very smooth ride and, most importantly, lower fuel consumption than a classic automatic gearbox with a torque converter and a system of parallel planetary gears.

The market is dominated by two types of gearboxes - the first ones are equipped with a set of wet clutches (usually 6-speed). The oldest version was the DQ250 variety used by Volkswagen with a torque of 350 Nm. The second type are gearboxes with dry clutches. They usually have 7 gears and work with engines with weaker parameters and lower torque. The oldest representative of this group was the DQ200 transmission, presented in 2008 (also by Volkswagen), adapted to engines generating a torque not exceeding 250 Nm (for comparison, the top dual-clutch gearboxes with wet clutches withstand torques twice as high).

Durability, operation and maintenance

Companies servicing dual-clutch gearboxes agree that their durability ranges from approx. 150 to 300 thousand km. Much depends not only on the construction of the gearbox itself, but also on the way it is used and the lubricants used. Interestingly - some drivers claim that their gearboxes work reliably despite the mileage higher than the mentioned one, but this is due to ... wrong belief and lack of comparison of the driving experience with a fully operational car. Some signs of wear progress very slowly, so drivers do not notice them, and over time they assume that „it's supposed to be like this”. This causes unpleasant surprises when selling a car. The seller declares the full efficiency of the car, which is suitable for renovation, because the gearbox „prolongs” gear changes, reacts with a long delay, jerks, etc.

Disregarding service activities in the case of dual-clutch gearboxes (similarly to other automatic transmissions) results from the fact that such service is expensive. Service, regardless of its type, after a mileage of approx. 200,000. km may cost, for example, several thousand euros.

TotalEnergies oils for dual clutch gearboxes

Oil change intervals are always specified by the manufacturer. It is important to strictly follow the instruction manual in such matters. Only where adequate data are not available, average values can be assumed. In the case of dual-clutch transmissions with wet clutches, we can assume a range from 60 to 150 thousand km. In transmissions with dry clutches, the oil generally works for life in light operating conditions. When we drive almost constantly in city traffic, we can recommend changing the oil after about 150,000 km or 10 years.

The main requirements for dual clutch transmission oils used with wet clutches are optimal friction properties for clutches and synchronizers, compatibility with friction materials of wet clutches, protection of synchronizers. In such cases, the oil has contradictory tasks - to reduce the friction coefficient on gear wheels, and by using special additives increase the coefficient of dynamic and static friction on wet clutches.

Dual-clutch gearboxes with dry clutches can be omitted in this case because they impose similar requirements on oils as classic manual gearboxes.

TotalEnergies FLUIDMATIC DCT MV

TotalEnergies offers special oils for dual-clutch transmissions with wet clutches. An example is the FLUIDMATIC DCT MV. It is a gear oil made in synthetic technology, intended for „wet” dual-clutch gearboxes, ensuring their proper operation. The product provides very good wear protection even under heavy loads and good compatibility with sealing materials. Thanks to its parameters, it is suitable for most commercially available dual-clutch gearboxes with wet clutches.

The use of an automatic dual-clutch transmission enables smooth gear changes and, most importantly, lower fuel consumption than a classic automatic transmission with a torque converter and a system of parallel planetary gears. If we have a car with such a gearbox, we must take care of it and remember to use the right, dedicated oil for this type of gearbox and change it regularly.

Piotr Karkocha, Technical Department, TotalEnergies Marketing Polska

About TotalEnergies Marketing Polska
TotalEnergies Marketing Poland has been operating in Poland since 1992 and has an established position in the motor oil market. It offers products from two well-known brands TotalEnergies and Elf. Since 2008, TotalEnergies also offers bitumen products and has a presence in the industrial specialty fluids market. In December 2014, TotalEnergies launched its first gas stations in Poland, thus entering the retail market. In 2021, TotalEnergies opened its first car washes and launched a project to establish an electric vehicle charging network.

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The business segment TotalEnergies Marketing & Services offers to its professional and private customers a wide range of energy products and services - petroleum products, bio-fuels, charging electric vehicles and related services, gas for transport by road and sea - to support mobility thereof and to help them reduce the carbon footprint. Every day more than 8 million customers visit our 16 000 fuel stations all over the world. As number four in the world in the field of lubricants, we design and sell high-efficiency products for motorisation, industrial and maritime sectors. So as to respond to the needs of our B2B customers best, we implement our sales forces, our international logistics network and our diverse offer. We operate in 107 countries where 31 000 employees of ours are close to all our clients.

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TotalEnergies is a multi-energy company that manufactures and sells energy in the global scale: crude oil and bio-fuels, natural gas and green gas, renewable energy sources and electric energy. 105 000 our staff members are involved in generation of the increasingly cheap, pure, reliable and available to the greatest possible number of people energy. Being active in more than 130 countries, TotalEnergies focuses its activities on sustainable development in all dimensions thereof, in particular in the area of its business projects and operations that shall contribute to increased quality of life of people all over the world.

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