What's with the snow gear of the automatic car?

Modern middle and high-grade automatic transmission vehicles are generally equipped with electronic throttle, TCS traction control and ESP vehicle stability dynamic control system. What is an electronic throttle? Electronic throttle is also called throttle flexible connection, which cancels the traditional mechanical connection and controls the throttle to locate quickly and accurately through the electronic control unit. Its advantages are that it can determine the best throttle opening according to the driver's needs and wishes and various driving conditions of the whole vehicle, ensure the best power and fuel economy of the vehicle, and have control functions such as traction control and cruise control to improve safety and ride comfort. Especially in hybrid electric vehicles, because the engine and battery constitute a multi-energy power system, the rigid connection mode can not realize the energy distribution management between power sources, so it will be replaced by the flexible connection mode.

The traction control system realized by electronic throttle, also called drive acceleration slip adjustment, can realize all the functions of ordinary snow mode itself, so this kind of vehicle sometimes has no snow mode button, of course, if there is one, it must be pressed when driving in snow. This snow mode reduces the engine power by reducing the throttle opening, thus achieving the control purpose. Firstly, ECU collects signals such as accelerator pedal position, wheel speed and steering angle of steering wheel, calculates the slip rate and generates corresponding control voltage signals. At this time, the throttle is controlled by these signals, which is not affected by the driver's intention, and the response to the accelerator pedal is reduced. The power output of the engine is less than normal, and the wheels are not easy to slip. Coupled with ESP system, by applying braking force to four wheels respectively, not only the anti-skid effect in auto start can be achieved, but also the driving stability will be quite high.

If it is an electronic throttle, but there are no auxiliary electronic systems such as TCS and ESP, then you need to start in high gear or press the snow mode button like an ordinary automatic car.