[YesAuto Test Drive] BMW Elite Driving Training starts again! This track driving training course, which was set up simultaneously with Germany, has now entered a new round of winter training. I believe that everyone has read a lot about the ice and snow test drive. When it comes to the ice and snow test drive, you may habitually think of various new technologies and powerful four-wheel drive equipment. But today we are not talking about new car new technology, nor XX four-wheel drive system, but through BMW driving training to learn to better play the limit of the car, and in extreme cases, do not rely on electronic equipment to rely on their own driving skills in the ice Driving a rear-wheel drive car on the surface.


Before we begin, I would like to emphasize again that when driving in a cold northern city, apart from various warm equipment, it is recommended to wear a pair of sunglasses, especially when driving in the snow for a long time! If you don't wear sunglasses, the snow-white environment can easily cause snow blindness-that is, a symptom of temporary blindness caused by strong light stimulation of the eye and retina, dangerous! (Even if you are not “blind”, looking at other things after a long time in the snow is still pink, which is uncomfortable.)

Straight to the topic, this article mainly explains how to make a middle-horsepower rear-drive car like the BMW 325i better control on icy and snowy roads. The main items include: accelerating, braking and avoiding obstacles, controlling oversteer; and understanding how to turn on the DTC system, only turn on The feeling when the DSC system, electronic equipment are completely turned off, and the corresponding driving method. This time, we use special winter tires instead of “nail tires”, which are closer to life. For more information about BMW driving training, please check the following articles:

Enjoy the fun of control experience BMW elite driving training
http://www.autohome.com.cn/drive/201101/139299-1.html


★ Glossary

DSC-Electronic Stability System : The function is the same as the ESP (Electronic Stability System) of Germany's Bosch, which can improve car handling, oversteer and understeer. Since the ESP name has been registered by the German company Bosch, the electronic stability system developed by other companies can only use other names, and the products under the BMW brand are called DSC systems.

DTC-Body Dynamic Stability System : This system integrates active safety technologies such as ESP system and traction control system, which can fine-tune the driving state of the vehicle more accurately to prevent loss of control.

How to use the DTC button on BMW models : short press to start or close the DTC system; long press for 3 seconds to completely close the DSC function, short press again to restore.


1. Start, accelerate-don't step on the accelerator

On ordinary roads, whether it is a wheel-driven car, it is very simple to get the fastest acceleration time, which is to press the accelerator to the end and cooperate with a reasonable gear shift. On icy and snowy roads, a large throttle can't help the car accelerate faster. For a rear-drive car, it will cause the rear of the car to swing, or even make a circle on the spot. This is what we usually call “Haste is not achieved.” .

Keep the DTC system open, even if you step on the accelerator more strongly, the traction control system will limit the torque output according to the degree of slippage, which is comfortable and safe. However, due to the limited torque output, acceleration is relatively slow. If you want to get better acceleration, you can try to turn off the DTC system. The power is limited and the wheel exerts force directly. The price is that the wheels will slide slightly laterally. You need to adjust the angle of the steering wheel to correct it even when you start. The vehicle is moving forward. In this case, the difficulty is not too great, after all, the DSC system is still working normally at this time, which can offset the excess slip.

The first two methods are all started with the help of electronic equipment. What should I do if I drive a vehicle that is not equipped with a DSC or ESP system in the future? This is the focus of today's training. When the two conditions of high horsepower and low adhesion occur at the same time, it is easy to slip, and the consequences of slipping in rear-drive vehicles are deviations and U-turns. The correct method is to step on the accelerator pedal slowly and linearly. When the rear wheel is detected to be slipping, the oil should be collected in time, and then stepped on. The main point is to keep the driving wheel from slipping excessively and maintain a certain traction to start smoothly. For automatic models with manual mode, using manual mode to start in 2nd gear is a very good way to prevent skidding at the start.

It is also very important to choose a road with high adhesion as much as possible. This is the simplest and most effective method. On icy and snowy roads, the adhesion varies greatly. The adhesion coefficients of soft snow, frozen snow and mixed snow and ice are different. The adhesion of soft snow is relatively good, so the problem of starting should be considered when parking. Choosing a road with greater adhesion when parking can easily and effectively solve the problem of difficulty in starting again.

Once a vehicle is stuck in a snowdrift, we must not continue to step on the accelerator. This will make the snow pits that trap the wheels become smoother and smoother, which is counterproductive. At this time, you should consider methods such as trailers, carts, and friction objects under the wheels to relieve the problem. Using so many words to describe a start is a bit wasteful, but this is the basis for safe driving, and ensuring a smooth start and acceleration every time is the basis for more tricks.

2. Around the pile-slow driving and refueling stably

The principle of winding piles on snow is basically the same as that on highways. However, due to the low adhesion of icy and snowy roads, the actions are relatively enlarged, requiring earlier judgment and timely adjustments.

Winding piles on icy and snowy roads requires the cooperation of hands and feet, which is the opposite of front-wheel drive vehicles. Deep stepping on the accelerator of a rear-drive vehicle will cause the rear of the vehicle to swing outwards to ensure the required steering angle. . When the DTC system is turned on, there is no need to estimate that much. Just turn on the direction and step on the accelerator. The electronic stability system and traction control system will help you correct the body's posture and route at any time. After turning off the DTC system, you can get more traction. At this time, you can use the throttle to make the tail swing slightly, but the normal working DSC system will also correct the thrown back in time. I personally think that this mode is the most fun for the BMW 325i.

3. Brake + dodge obstacles

Needless to say, do straight-line braking on icy and snowy roads, as long as you keep the direction straight ahead and depress the brake pedal to the end (because the ABS can't be turned off) until it comes to a complete stop. But if there is an obstacle ahead that needs to be braked and dodged, a certain skill is required.

It should be noted in the dodge link that the force of turning the steering wheel should be soft and the amplitude should be small. If you use the brakes at the same time, you should brake with full force in the early stage of braking, that is, in the straight phase, and reduce the speed as much as possible before dodge. At the moment of turning the steering wheel, you can release the brake appropriately to get more adhesion to help steering. If the steering is too large or too strong, it is likely to cause loss of control.

4. Control oversteer-drift!

From the above description, everyone should already know how to make an oversteer action, which is drift. First of all, we need to completely turn off all electronic equipment, press the DTC button on the center console for 3 seconds, and master the actions: enter the corner, hit the direction, step on the accelerator (the tail is thrown out), and quickly reverse. Direction and oil collection, fine adjustment of direction and throttle can ensure continuous drift.

On icy and snowy roads, drift can be created without too much throttle, and the throttle adjustment is also slight. If the vehicle continues to step on the throttle when the vehicle has understeer, it will lose control. Another point to be emphasized is that in the process of drifting, you must focus on the direction the vehicle is going to drive, not just the situation in front of you. The decision to go in the direction is to decide when to refuel and when to drive. The premise of the direction, otherwise it will soon be dizzy on the spot.

★It is recommended not to completely shut down the DSC system under normal circumstances, safety first! If you want to show off, turning off DTC is enough. And after returning to normal roads, all electronic equipment must be restored in time.

Edit comment:

The BMW brand pays attention to sports. The beautiful drifting action seems to have become BMW's signature, but this training is more about telling us how to spend this winter safely with our car. Drifting is beautiful, but the purpose of training how to drift is not to train racers, but to teach you how to use your driving skills to control when you are about to lose control, and really do it with ease. (Pictures, texts, photos/Car home Wang Miao)