How to use the+and-of automatic transmission? What should I pay attention to?

There are not many suitable scenes for+/-gear and M gear of automatic transmission, which are mainly used for traction, engine braking and starting on ice.

Automatic gear: D has four gears: S, L and M. In most cases, only D is enough, because in D, no matter how many gears, the driving gear will be automatically adjusted between 1~6 or 1~ 10. The forward gear is controlled by the vehicle speed, and the vehicle speed is controlled by the throttle.

The above three road conditions are the roads where most cars run normally, so the D gear can meet the needs of using other gears. Even if overtaking, the acceleration process is no slower than shifting to S gear (provided that the power reserve is sufficient). Then only special scenes need to use special driving gears, such as titles.

(1) traction, automatic cars need to use M or L gear when towing trailers or rescuing other vehicles, because the towed cars, whether trailers or cars, have great curb weight, even if the tire rolling resistance is less than the real weight, it will still burden the gearbox gear. However, after the speed of automatic transmission is high enough, the upshift will be more active. If the actual speed is not high but the driving gear is too high, the pinion driven by the big gear will be overloaded, causing serious wear. Therefore, in this case, it is necessary to use M to simulate the manual gear to improve the speed with a lower gear and then to a higher gear. L gear is a low gear, just like 1~2 gear of the active gear. If there is no M file, you can use L file.

Secondly, when the dual clutch gearbox is towed, whether it is wet or dry, it is necessary to use up and down gears, because the clutch will be linked for a long time and a half in the process of low-speed acceleration shift. The variable linkage refers to the sliding friction between the clutch plate and the static plate, and the essence of speed inconsistency is to wear the clutch plate. Only by gradually controlling the shift in automatic manual mode can the semi-trailer time be reduced and the clutch be more durable.

(2) Engine braking is suitable for long-distance downhill for several kilometers or even more than ten kilometers. Even with the disc brake system, continuous downhill will overheat and reduce the braking force. The only way to cool the brakes and control the speed is engine braking. The principle of braking is to use low gear when going downhill.

When the vehicle goes downhill under the action of gravity, the wheels will be driven by the vehicle body, and the wheels will drive the gearbox gear through the transmission shaft, which in turn will drive the engine. For example, if the engine pinion is driven by the reverse gear in the high gear, the engine speed cannot be increased. When the engine speed is within the range of forward idle speed, the vehicle will automatically accelerate when the fuel is cut off. Only when the engine speed reaches the forward idle speed can engine braking be realized.

When going downhill, when M gear is changed to 2 ~ 3 gear, the combination of gear sets will change, the gear driven by the engine will become smaller (A), and the gear output to the wheels will become larger (B), which will rapidly increase the engine speed. After exceeding the idle limit, the engine will actively exert force on the pinion to limit the speed of the big gear, which is the principle of downshifting engine braking.

③ Starting from the ice, the principle is simple; The friction between ice and tire is1/7 ~110. The transmission ratio of low-speed 1~2 gearbox determines that the output torque is very large. Once the torque is greater than the friction, the vehicle will slip out of control.

On this kind of road surface, it can be manually upgraded to 2~3 gears to accelerate slowly, and the torque output is less than the friction force on the ice, so the vehicle can start stably under the condition of slow power output, so it is reasonable to start using high-grade gears on the ice.

In the above three cases, you need to use the manual-automatic transmission mode or low-speed L or S gear, and you will gradually master the driving skills after gradually contacting more roads during the car use; D, M and S gears can be switched during driving, and L gears can also be switched, but the engine braking will be very obvious. Unless the brakes fail, it is not recommended to switch L gears during driving.

(The above is written by Tianhe Automobile and only represents personal views; Reprinting is forbidden outside the station, and forwarding is welcome inside the platform. )

If the automatic transmission has+-two signs, it means that it is an automatic gearbox with manual transmission, and+-is used for manual gear shifting, which will enhance driving pleasure.