The most important thing in a car is performance. Today the car editor needs to give you a brief introduction to the car's gearbox. If a car doesn't shift gears quickly enough and the shifting logic isn't smart enough, many people won't say it's good. Some people wouldn't notice it very well if the transmission was rather slow, but the transmission has a setback in shifting. Do you know what the problem is?
Why is the gear shift unstable? Why is the gear shift unstable?
The function of the gearbox is to adapt to different driving conditions by changing the speed ratio between the engine and the wheels. Simply put, it is to select gears of different sizes to be combined with the engine. Shift rollback means that the process of the gearbox switching between two different gears breaks the original inertia, and the sudden force will react on the vehicle body, causing rollback. In most cases, the lower the gear, the higher the engine's torque amplification ratio and the more obvious the slump, so most of the slump occurs in the process from 1st gear to 2nd gear or 2nd gear to 3rd gear.
Why is the gear shift unstable? Why is the gear shift unstable?
The ideal way to eliminate frustration is to have the gear speeds on the input and output sides of the clutch exactly similar on every shift. It's not impossible. After a period of exploration, experienced drivers have learned the approximate speed difference of each speed of this car and the speed at which the engine speed drops, and have found a smooth shifting rhythm. Since it is a manual transmission, it is impossible to control the speed of each gear so accurately. Another thing that veteran drivers do is to first lift the clutch 70 degrees, so that the clutch is semi-linked, and the engine and gearbox speeds are slightly synchronized year-on-year. This can also shorten the frustration, even to the extent that people in the car cannot feel it.
Why the gear shift is erratic: The automatic transmission shifts erratically.
For automatic transmissions, the rollback mechanism is the same. Basically, it causes the speed to drop and the synchronization process after shifting is not precise. Let’s first talk about how the three automatic transmissions we often encounter deal with shifting frustration.
Automatic transmission
The traditional AT transmission relies on a hydraulic torque converter as a flexible transmission element. Compared with the so-called soft and rigid, the clutch transmission is a rigid transmission. For example, I need to make a ball floating on water move. I can just pitch the ball. This is a rigid transmission. No, I can also have the water stream and the ball float along the stream, which is flexible transport. Therefore, AT gearboxes are usually easy to smooth and rely on the torque converter. Since it is a hydraulic transmission, it will naturally lose part of the energy consumption. Therefore, the symptom of fuel consumption has become a shortcoming of the AT gearbox.
However, recently, there has been a new breakthrough in the field of AT gearboxes in China. The 6AT gearbox newly developed by Dongan Automotive Development (DAE) has excellent performance in terms of energy consumption and has reached the world's advanced level. Initially, DAE6AT uses a hydraulic torque converter with an ultra-long stroke shock absorber, which reduces the locking speed to 1000RPM and supports slip adjustment. Combined with engine adjustment, it can realize direct connection after starting, which can effectively reduce the loss caused by the hydraulic torque converter. Secondly, adjusting the main oil pressure through torque tracking and reducing the oil pump back pressure can reduce oil pump losses and improve efficiency. The friction plates then use special oil grooves to reduce drag torque losses.
At the same time, the DAE6AT shift solenoid valve uses a linear proportional pressure reducing valve. Compared with the pulse width modulation valve and VBS solenoid valve, the adjustment accuracy can be improved by about 40%, and the shift response can be improved by 10%. Coupled with the miniaturization and lightweight design style, compared with currently mass-produced competitive models, performance symptoms such as power, volume, and density are quite good.
Dual clutch
The Volkswagen DSG gearbox shifts quickly and smoothly, but as I mentioned before, shifting can only be smooth if the speed difference is digested. This is a law of physics, and it is different from what the gearbox uses. The gearshift structure has nothing to do with it.
So why does the Volkswagen series dual-clutch transmission shift quickly and smoothly? This comes from Volkswagen's patented technology that regulates the engine to maintain a certain speed after the throttle is opened. Think about it. When the transmission TCU (transmission adjustment unit) prepares to upshift, it sends a signal to the electronic control unit to close the throttle.
At this time, when Volkswagen can quickly fix the engine speed at the speed corresponding to the next gear, then in the process of completing the switching of two sets of clutches with dual clutches, the semi-linkage process of synchronous speed can be omitted or greatly reduced, allowing The clutch fully engages faster.
Continuously variable transmission
Of course, the CVT transmission is the most innate advantage in terms of ride comfort. CVT gearbox is also called continuously variable gearbox. As the name suggests, CVT has no concept of gears, so CVT naturally does not have gear shifting frustration. The transmission method of its gearbox is similar to that of a self-driven chain transmission. But the difference is that the transmission ratio of the driving wheel and the driven wheel of the CVT gearbox can be changed. By changing the groove width of the driving wheel and the driven wheel through the hydraulic mechanism, the transmission ratio can be slightly increased.
Today, this is the end of the introduction to the car series. The above is a brief introduction by the car editor on why gearbox shifting is frustrated. A car's gearbox is very critical. For supercars, gear shifting efficiency is critical. Have you ever encountered such a problem? I hope the car editor’s introduction can help you solve your problem. If you want to know more about the small car series, please pay attention.
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