Many people say that there is a sense of frustration in dual-clutch operation. What is that sense of frustration?

I often hear people say that a certain automatic transmission has severe sluggishness, so that some people "change their expressions after hearing the sluggishness." So what exactly is sluggishness? Let’s talk about this topic today.

The word "dunset" has two characters, namely "dun" and "setback". The pause and setback of a car can be broken down into two driving states, and the Chinese meaning of these two words actually explains the pause and setback. Dun

Dun means pause in Chinese. The feeling of a sudden pause when a car is driving can be called a pause. For example, if you drive a manual transmission car and release the clutch quickly after downshifting, the engine braking force will suddenly decelerate the vehicle, and the front of the car will suddenly sink. This feeling is called a pause. Automatic transmission "pause"

The main reason for automatic transmission "pause" is that the engine braking force caused by downshifting is too obvious.

Several situations where "pause" is likely to occur

1. Deceleration

When decelerating, the transmission must downshift after the vehicle speed reaches a certain level, and the gear The lower the corresponding engine speed, the higher the engine speed, and the engine braking phenomenon is most likely to occur, causing "pause".

2. Downshift from 2nd gear to 1st gear

Because the gear ratio gap between 2nd gear and 1st gear is very large, it is difficult to match the speed when downshifting, so "pause" is most likely to occur. Feel. For example, when you drive in 2nd gear, the vehicle speed is 10 km/h, the engine speed is 1200 rpm, and when you drive in 1st gear at 10 km/h, the engine speed is close to 2000 rpm. Therefore, if the engine speed is too low after downshifting, there will be obvious engine braking force.

3. Release the accelerator

There are two situations when releasing the accelerator causes "pause". One is that the engine brakes after releasing the accelerator during normal driving. This is normal, and the accelerator is released. The rear engine generally reduces torque slowly, so this feeling is not obvious.

The other is to release the accelerator when the transmission downshifts. This situation is easy to encounter in daily driving, and it is easy to stop no matter what transmission is encountered. For example, if you step on the accelerator and drive normally, but the power is insufficient at this time, the gearbox downshifts. As a result, the gearbox is downshifting and you release the accelerator, then it is easy to pause. Because the engine speed will increase after changing gears, and you unexpectedly release the accelerator, causing the engine speed to decrease, causing engine braking. The car will pause.

Originally, the gearbox determines the shifting speed and timing based on your previous accelerator opening. Unexpectedly, you let go of the accelerator before the shift is completed. This suddenly disrupts the gearbox plan. , a pause is of course inevitable. The word "setback" means "press down" in Chinese. We can use a more vivid homophone to explain it, which is the word "file".

The thing in the picture above is called a "file". In the machining industry, it is a tool used by fitters to trim parts. Friends who have seen it must remember its usage: press the file tightly against the part that needs to be polished, and then push the file forward firmly to polish the part. The action of pushing forward with force is called "filing".

The gearbox's frustration manifests itself as a sudden release of power, causing the car to suddenly accelerate forward. Automatic transmissions are prone to "frustration" in several situations

1. High-throttle acceleration

Because high-throttle acceleration means that the driver has a relatively large acceleration demand. At this time, the transmission will give priority to shifting speed at the expense of smoothness. At this time, the gear shifting speed will be very fast, and the engine power output is also large, so there will be a big impact when shifting gears, but this impact is uniform, and you can feel the pleasure of acceleration, so this kind of "frustration" is generally normal. towards.

2. Small throttle acceleration

When accelerating with a small throttle, the engine output torque is very small, the vehicle acceleration is also very small, the engine speed slowly climbs, and the gearbox begins to shift when it reaches the shifting speed. .

When the gearbox shifts gears, it will send a request to the engine to reduce torque to reduce the impact. However, when accelerating with a small throttle, the output torque is inherently small, and more driving force is required after shifting gears, so the engine It is necessary to adjust the torque within a small range and ensure the torque demand after shifting, so it is difficult to take into account the smoothness, and it is easy to intrude at this time.

3. Driving when the car is cold

When the car is cold, the engine fuel injection is thickened and the power is abrupt. Moreover, the transmission oil temperature has not reached the normal temperature and the viscosity is greater. When shifting gears, The oil pressure is difficult to control, so it is prone to intrusion, which is called "frustration".

Generally speaking, transmission failure can be attributed to poor shift quality and malfunction. In some cases, poor shifting quality will inevitably occur due to objective reasons, so it is normal for the gearbox to falter at this time. The frustration during failure is what you really need to pay attention to.