[Aika car shopping guide original]
The development of automotive drivetrains has been evolving with the evolution of automotive products, from the initial MT manual transmission to a variety of "automatic" transmissions. Among them, the DCT dual-clutch transmission is widely known for the continuous promotion of Volkswagen. This is especially true of porsches, the PDK gearbox. So what is unique about the Porsche PDK transmission, and why can it be a different firework?
If you ask which brand the dual-clutch transmission originates from, many people may guess Volkswagen or Porsche, after all, DSG and PDK have long been deeply rooted in the hearts of the people. But about its technical prototype, in fact, Citroën engineer Adorphe Kégresse proposed in 1939, from the design drawings, its structure has been very close to today's dual-clutch transmission, but the lack of electronic control system. The package was originally planned for the Citroën Traction Avant model, but the project was terminated due to budget and World War II.
After the end of World War II, the automotive industry was in ruins, and the plan to "build a gearbox that can integrate the advantages of manual transmissions and avoid the disadvantages of automatic transmissions" has been proposed. So in the late 1950s, two Britons prototyped a mass-produced dual-clutch transmission and installed it on the Hillman Minx model in 1961. It used analog signals and solenoid valves for shifting, but unfortunately the operation was not very reliable, and finally it was replaced by a manual transmission.
With the experience of their predecessors close to success, Porsche's designers and engineers also became very interested in the dual-clutch transmission and began to study the power shift dual-clutch transmission, which is mechanically controlled by the cam disc. Soon after, an engineer named Imre Szodfridt came up with the idea of reworking the dual-clutch transmission, and eventually the Model 919 transmission was created. However, there is no suitable electronic control technology, can not solve the dual clutch gearbox gear shift setbacks, NVH difference and other issues, codenamed 2612 PDK project had to be suspended research and development.
However, it is often the emergence of crises that advance technology. In the 1970s, the German federal government organized an automotive industry competition called "Vehicle 2000" to encourage car companies to develop a variety of different technologies, Porsche after comparing different gearboxes, Helmut Flegl, then head of Porsche's senior research and development department, believes that a dual-clutch transmission may be more promising. As a result, the PDK project, code-named 2612, was restarted.
Although the project was restarted, it still faced a severe test. Because at that time, there was neither a powerful electronic control equipment nor an electro-hydraulic valve suitable for mass production of automobiles. Finally, after modifying the prototype gearbox and creating a basic control algorithm in assembly language, a prototype of the PDK gearbox was finally developed, which was subsequently demonstrated on a Porsche 924 model. At this point, the PDK gearbox was finally born, and the year was 1981.
Although the PDK transmission passed the loading verification, Porsche did not mass produce it immediately, because Porsche has a tradition that a new technology generally has to be fully verified on the track before it can be loaded into a production car. So engineers pushed it to its limits and put it in tough rallies and endurance races. At the end of 1985, rider Walter R hrl drove the Audi Sport quattro S1 equipped with the technology to the Austrian rally Semperit Rally, making his debut.
In 1986, Hans Joachim Stuck teamed up with Derek Bell to win the first victory in the Monza 360 km in a Porsche 962 and won the year's world championship. In the same year, Hans drove the 962 and won the title at the ADAC Würth Supercup, a prestigious competition in Germany. Consecutive wins made the Porsche PDK gearbox famous for a while.
Although PDK has many advantages such as fast gear change speed, high transmission efficiency and good stability. However, due to the fact that porsche still needs to rely on supplier support at the end of the 1980s, the complex PDK gearbox cannot effectively control the cost, and the mass production plan on civilian vehicles has to be shelved again. Of course, Porsche's engineers were not idle, and they turned their attention to the automatic transmission. So in November 1981, a hydraulic torque converter automatic transmission with manual shift function for production cars was officially introduced, which was also known as the Tiptronic hand-integrated transmission. The Porsche 993, 996, 986 and even the 997 before 2008 were equipped with this gearbox.
At the beginning of the 21st century, automotive electronics technology has made great progress, and electronic control technology has become more mature. In 2002, the Audi TT, equipped with a wet dual-clutch transmission from BorgWarner, marked the birth of the world's first production dual-clutch transmission.
Although with the birth of the BorgWarner wet dual-clutch transmission, the demand for porsche PDK transmissions is also increasing. But Porsche didn't equip the PDK transmission on the mid-term 997 until 2008.
Today, Porsche PDK transmissions are arguably the perfect balance of efficiency and performance. The most sporty cars in the Porsche range are equipped with PDK transmissions, including the latest 718 Cayman GT4 RS.
What you don't know about PDK – History
After reading the history of the birth and development of the Porsche PDK transmission, let's talk about technology. Since the birth of the dual-clutch transmission, the advantages of high transmission efficiency and fast gear change speed have never been surpassed by other gearboxes, but natural defects such as low speed setbacks and quality stability have also been criticized. However, in the Porsche PDK gearbox, the defects about the dual-clutch transmission seem to have all disappeared, why can it become a different firework alone?
In the official promotion of Porsche, the performance of the Porsche PDK transmission, even if it starts with 50 consecutive ejections, the transmission performance will not decline, and each catapult will have a very strong feeling of pushing back. In order to have eye-catching performance, precise computer control is required to make the gear shift combination most efficient to reduce clutch overheating; independent cooling system to meet the heat dissipation demands of extreme operating conditions; and top-of-the-line material use to make PDK gearbox redundant to deal with unforeseen situations. To sum up, there are two key words "the pursuit of performance" and "regardless of cost".
Volkswagen and many domestic car companies vigorously promote dual-clutch transmissions, not because of good performance and high comfort, but more importantly, because of saving money. You know, the cost of Volkswagen purchasing a 7-speed dual-clutch transmission is only a few thousand yuan. But porsche's purchase of a PDK gearbox is said to cost more than 100,000 yuan.
From the point of view of working principle, Porsche's PDK transmission does not seem to be special compared to other dual-clutch transmissions. Take the Porsche 7-speed PDK transmission, for example, which is actually a parallel switching transmission consisting of two fully synchronized meshing sleeve transmissions. So where did all this hundred thousand yuan go?
The first is the material. Many people think that the dual-clutch transmission is more fragile than the hand-integrated transmission, which is actually determined by the working principle, because the inside of the dual-clutch transmission is a direct hard connection, and it does not have a hydraulic torque converter in the hand-integrated transmission structure that can offset part of the engine when it outputs large torque, so the torque transmitted by the engine is directly output to the gears and friction plates of the dual-clutch transmission, so if the material strength of the gears and friction plates is not enough, it is easy to be damaged. In order to withstand high torque at all times, the gears and friction plates of the Porsche PDK transmission are made of heat-resistant and wear-resistant alloys, and the sharp increase in the strength of the parts is followed by a soaring cost.
With high-strength materials, a foundation for "the pursuit of performance" is laid. The pursuit of performance is nothing more than to make the gearbox's upshift and downshift faster. But in order to make the gearbox shift faster, this is related to the gearbox shift hydraulic system, in general, the gearbox has only one oil chamber, and the oil inside undertakes all the work of lubrication and hydraulics. In order to avoid interfering with each other's work, the PDK gearbox simply sets up two oil chambers to undertake lubrication and hydraulic work respectively.
With the division of labor and cooperation between the two oil chambers, the PDK gearbox lifting and lowering speed has been greatly improved, but the dual-clutch gearbox is born structurally, and the gear shifting process has always been in a state of hard connection and hard impact, even if the gears and friction plates made of heat-resistant and wear-resistant alloys are difficult to resist the thermal decline caused by long-term friction. To this end, the PDK gearbox adopts a double cooling oil partition and a special cooling line, which controls the cooling oil flow control for the temperature of the dual-clutch system, so that the double-clutch will not change gears under various working conditions, and the performance of the double-clutch will not decline due to overheating, and even the transmission will be self-locking due to overheating.
Of course, everything is in case, in order to avoid extreme cases due to transmission overheating caused by damage, PDK transmission added a set of transmission overheating protection system, through a variety of sensors to collect transmission oil temperature, while TCU is responsible for calculating the temperature of the clutch system, to ensure that in each working condition, the gearbox can always be in the ideal state. If the gearbox is in a high temperature state all the time, then the PDK will enter a limp state, and in this state the gearbox will enter a self-protecting state until the transmission fault code disappears.
Editor's comments: Compared with other brands' self-developed dual-clutch transmissions, it is different to get rid of supplier constraints and reduce costs. Porsche developed the PDK gearbox originally to cope with more extreme and demanding conditions, so it does have a unique point that is different from other dual-clutch transmissions. While the complex and unique design and higher strength of the material cause costs to fly, in exchange for its core advantage - high durability. Although today's electric vehicles have gradually made traditional fuel vehicles less fragrant, no matter how the times and technology are iterated, there is one thing that will never change: love. Like Imre, Rainer and Hans, without them, there would be no PDK legend.
Highlights review:
Everyone talks about "manipulation", but what is it?
Test how well you know about cars Convertibles have so many names
Specializing in "heart disease" BorgWarner's engine technology
What you don't know about PDK – technology