How does high speed rail brake? How to brake and slow down the high speed rail

First of all, it is clear that high-speed rail refers to high-speed railway, and it should be said how the EMU brakes.

Braking devices and safety devices for high-speed EMUs.

From the time of receipt of the notification to the completion of the emergency braking procedure, the effective time left for the driver is very short, otherwise he will collide with the vehicle in front. As a safety measure, satellite communication devices must be installed on each train, and the main computer of the general dispatching room of the whole line transmits safety signals through satellites every few seconds, and when there is a situation, the brake instructions are issued to all trains synchronously by satellite, and the locomotive computer does not detect the manual braking operation within the specified time after receiving the signal, and it is transferred to the automatic braking program. For the problem that the signal can not be received in the tunnel, a directional antenna can be installed at the rear of each train, and the brake signal is sent backward when the car brakes, and the rear car has a receiving antenna at the front of the locomotive.

Harmony"The maximum speed of CRH3 EMU is 350 kilometers per hour, such a high speed will reduce the grip of the train, and a computer-controlled wind wing (speed brake) can be installed on the top of each car box, and when the wheel pressure is detected to drop abnormally, the wind wing (speed brake) is appropriately raised, and the train is pressed back to the ground with wind resistance at high speed. The wind wing (speed brake) usually clings to the roof to reduce resistance, and when the emergency braking is fully opened, the wind resistance at high speed is used to slow down, so that the train can be reduced from high speed to medium speed in a short time, so that the wheel does not slip when the wheel brake device works. Wind wing (speed brake)** should leave the position of the power wire to prevent the wind wing (speed brake) from touching the power wire after it is raised.

Brake discs and brake calipers vary according to different models, CRH2 moving axle two-wheel disc, tow axle two-wheel disc two-axle disc; CRH5 has two axle discs on the moving axle and three axle discs on the tow axle, one brake caliper (two brake pads) for each axle disc.

When braking, the EMU first gives priority to regenerative braking, when the braking force is insufficient, the adjacent trailer then implements air braking, if it is not enough, the EMU then implements air braking.

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How is high-speed rail braked? The domestic high-speed rail braking gives priority to the use of regenerative braking, which is to convert the motor into a generator, and return the power to the power grid through electric energy deceleration, which is a very environmentally friendly braking method, and the disc brake is used only when the power grid is faulty and emergency braking. There is a disc turbine brake and a resistance brake.

The braking system of high-speed rail is like this:

The braking control device of each vehicle of the EMU adopts microcomputer control, which is composed of the electric braking (regenerative braking) of the EMU and the air braking (disc braking) of each car, and has the function of coasting detection in the brake control device.

Since the adhesion coefficient decreases as the speed of the train increases, the braking force is set to change the speed of the braking force with the change of speed, and the braking force is controlled by the adhesion mode.

This mode is based on the adhesion test on the premise of rainy weather, so the train can be guaranteed to stop at a specified distance when braking, so that it will not slide too early.

High-speed rail braking is slightly more complicated, because high-speed rail is faster and the braking distance is longer, so a variety of braking forms are combined, namely: air braking, hole hood braking and non-adhesive braking.

When braking on high-speed rail, regenerative braking is used first, because each carriage has a braking system, which reverses the engine into a generator when braking, and turns the kinetic energy provided into electric energy, and then implements air braking, which is similar to the braking principle of ordinary trains.

In order to ensure the safety of all high-speed rail operations, all connected to the satellite, the main computer of the general dispatching room every few seconds, will broadcast a safety signal through the satellite, when there is an emergency, it will use the satellite to synchronously issue braking instructions to the train on the railway line, and the computer on the high-speed rail will immediately switch to the automatic braking program if the manual braking operation is not detected within the specified time after receiving the signal.

Instructions for high-speed rail braking

The top of the high-speed rail also has a computer-controlled airbrake. According to the principle of fluid mechanics, the faster the speed, the lower the pressure. The lower part of the high-speed rail speed plate is arc-shaped, and the upper part is flat, so that the air flow below is fast, and the pressure on the top is stronger than that below, and the wind resistance at high speed presses the train to the ground.

Once the brake is urgent, the wind will absorb the wings, increase the resistance, and stop the train as soon as possible.

In the process of high-speed rail driving, the train control system will continuously collect the actual time guessing status and operating conditions of the line. If there is an abnormality in the line, or the speed of the train exceeds the safety red line, the train control system will adopt corresponding safety protection measures and automatically output braking to ensure the safe operation of the train.

The above content reference: Encyclopedia - high-speed trains.

High-speed rail trains are operated with handles to speed up and brake. There is no accelerator and brake pedal on the high-speed rail train, the joystick is the joystick that realizes the acceleration and deceleration function, the brake (brake) function is the brake machine, and the driver adjusts the speed or stops through the handle. The foot pedal of the EMU hand orange train is not used for braking, but to ensure that the driver's mental leakage is highly concentrated, and it needs to be pressed regularly.

Basic characteristics of high-speed rail1. The high-speed railway is very smooth to ensure the safety and comfort of driving, the high-speed railway is seamless rail, and the high-speed railway with a speed of more than 300 kilometers per hour adopts a ballastless track, that is, there is no stone in the integral track bed to ensure smoothness.

2. The high-speed railway has few curves, a large curve radius, and the turnouts are all movable high-speed turnouts.

3. A large number of viaducts and tunnels are used. to ensure smoothness and shorten the return distance.

4. The catenary of the high-speed railway, that is, the suspension of the wires on the top of the train, is also different from that of the ordinary railway, so as to ensure the contact stability and durability of the high-speed EMU.

In China, high-speed rail EMUs use composite braking. In normal braking, the priority is to use "regeneration system leakage", that is, the motor is "reversed" into a generator, and the kinetic energy of the EMU is converted into electrical energy, which is used by the EMU in the adjacent section through the catenary. When the EMU is about to stop, it is changed to "mechanical braking", which works in the same way as the automobile brake disc.

The high-speed rail encounters power outages and other failures, and the emergency braking is also in "mechanical braking" mode.

The whole braking system is filled with compressed air for braking, and when braking, the motor car gives priority to regenerative braking, and each compartment has an acceleration braking system, which accelerates together when accelerating and brakes together when braking. When braking, regenerative braking will be preferentially used, that is, the engine will be reversed into a generator, and the kinetic energy provided will be changed to the electric energy; When the braking force is insufficient, the adjacent trailer will apply air braking, and if it is not enough, the EMU will implement air braking again.

China's 350 km/h Fuxing high-speed EMU, emergency braking requires about a kilometer braking distance. Under normal braking, a braking distance of 8-10 kilometers is required. The "extreme" challenge of 613 kilometers per hour and the braking distance of only one kilometer is not "realistic".

Experts said that the "hyperloop passenger cabin" is still in the principle verification prototype stage, and it is still far from the engineering prototype.

Domestic regenerative braking, disc braking, foreign eddy current braking, electromagnetic eddy current braking, magnetic rail braking, resistance braking, brake shoe braking.