Dual clutch transmissions are highly efficient. Mobil™ offers a multi-grade oil for this type of transmission.
The first production dual clutch vehicles appeared in 2003. In English they are called Dual Clutch Transmission (DCT). Such automatic transmissions provide vehicles with high efficiency and dynamics due to very fast gear changes and are therefore used both in mass cars and sports cars. All modern Ferraris, Bugatti and Alpine are equipped only with DCT, and Porsche puts such transmissions on all models except crossovers. They are also used on smaller models, such as the Mercedes-Benz B-class or the Skoda Rapid.
How they work
DCT is a kind of robotic gearboxes. Their principle of operation is the same as that of conventional mechanical ones — gears also transmit torque here, and during shifting, when starting or stopping, the clutch disconnects the gearbox from the engine. In robotic transmissions, the computer controls the gear shift and clutch.
The use of dual clutch (DCT) allows, when working in one gear, to engage another in advance, and then, by simultaneously depressing the working clutch and closing the other, almost instantly change gear. Switching almost without interruption in the power flow allows you to maintain the dynamics of acceleration.
An old idea
The use of two clutches was proposed in 1935 by the French engineer Adolf Kegress. He is known for the fact that before the revolution he was in charge of the technical part of the garage of Nicholas II and in Russia he designed a removable caterpillar mover for cars. After returning to France, Kegress worked for Citroen. Kegress proposed his own automatic transmission design for the new Citroen Traction Avant model, but the company was unable to finance the development for various reasons, including the outbreak of the war.
In the United States, after the war, hydromechanical transmissions began to be developed, and in In Europe, the demand for expensive automatic transmissions was small, and almost no one was engaged in them. In addition, Kegress patented his design and it could not be copied. The patent expired in the seventies, and the English company Automotive Products decided to implement the long-standing idea, but it never came to production.
The first dual-clutch gearboxes were installed in the racing Porsche 956 in 1983 and then in the Audi Sport quattro S1 in 1985. True, in them the driver had to choose the gear himself, and when starting and braking, squeeze the clutch. Ferdinand Piech, the famous engineer and top manager, was then engaged in the sports direction of Porsche and Audi. Following the results of the races, he decided to transfer the sports experience to production cars. But from the preselective transmission, they decided to make the box fully automatic. So in 2003, the Volkswagen Golf R32 introduced the DSG, the first mass-produced dual-clutch transmission. Soon it was adapted for several Audi models, then dual-clutch transmissions began to appear on other models, primarily sports ones — Bugatti Veyron, Nissan GT-R and Ferrari California. In 2008, the well-known transmission companies Getrag and ZF mastered the production of DCT. They began to be installed not only on sports, but also on ordinary models, for example, Renault Megane and Ford Kuga, etc.
The share of dual clutch transmissions in Europe has increased from 10% in 2012 to 15% in 2020.
Special requirements
Clutches in such transmissions are of two types — dry, which operate without lubrication, and «wet», in which multi-plate clutches operate in oil. The latter are designed to transmit high torque and are used in sports models with powerful engines. Therefore, dual-clutch transmissions need a special oil: after all, it not only lubricates the gears, but also acts as a coolant for the clutches, as well as hydraulic — it works in the clutch and gear shift drives.
Transmissions with dual clutch systems are produced by car manufacturers themselves or their subsidiaries (Volkswagen, Fiat, Hyundai, Daimler, Honda) and specialized companies (Getrag, ZF, Eaton, Graziano, Ricardo, Getrag Ford Transmissions joint venture).
< p>For dual clutch transmissions, Mobil™ offers a special Mobil™ DCTF Multi-Vehicle oil. It is a high performance full synthetic fluid designed for European, American and Asian dual clutch transmissions, including wet type dual clutch transmissions. Among them are transmissions for Audi, BMW, Bugatti, Chrysler, Ford, Mitsubishi, Nissan, Peugeot, Citroen, Renault, Seat, Skoda, Volvo, Volkswagen.
Mobil™ DCTF Multi-Vehicle specifications details: vk .cc/c6eOA2