The Principle and Application of Speed Control System of Modern Cars

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The Principle and Application of Speed Control System of Modern Cars [Copy link]

Many cars now have speed control systems. Speed Control System is also called Cruise Control System, abbreviated as CCS. The name CCS is adopted by most cars equipped with speed control systems, which is a bit far-fetched. Because the word "cruise" is only used on airplanes and ships, it has always been called aviation and navigation, not land or land. Maybe the speed control system was transplanted from airplanes or ships, or it was a foreign English word, so the automobile industry just made a mistake and called it CCS. In some cars in China, the Chinese interpretation of CCS is cruise control system, and it is clearer when the word "fixed speed" is added.

Speed control system is a device that reduces driver fatigue. When a car is driving on a long-distance highway, starting the speed control system can automatically fix the car at a specific speed, eliminating the driver's pain of stepping on the accelerator pedal for a long time. In addition, there are benefits of saving fuel and reducing emissions, because cars have corresponding economic speeds, and when the driver adjusts the speed control system to the economic speed, it can save fuel.

The highways in the United States are well connected. Speed control systems have been widely used in cars since they were first used in the United States in the 1960s. Most mid- to high-end cars in Europe and Japan are equipped with speed control systems. Domestic cars such as Shanghai Passat, Shanghai Buick and Guangzhou Accord are also equipped with speed control systems.

As the name suggests, the basic function of the speed control system is speed control. When the speed setting switch (Set) is pressed, the speed at that moment can be stored and automatically maintained. When speed control is not needed, as long as the brake pedal is pressed, the speed setting function will stop immediately, but the speed information will continue to exist. If you want to restore speed control, press the resume switch (Resume) to restore the original stored speed, and the car can drive at this speed again.

In addition to the above basic functions, the speed control system can also add the following functions: acceleration (Accelerate) or deceleration (Coast) function. Continue to press the switch to continuously accelerate or decelerate, and enter the speed control system at the speed when the switch is not pressed. There is also a low-speed automatic elimination function. When the speed is below 40 kilometers per hour, the system's stored adjustment speed will automatically disappear and cannot be restored.

The speed control system is an automotive electronic control system that uses a speed sensor to input the speed signal into the ECU (electronic control unit), which then outputs a command to control the throttle system. In such a system, the engine throttle opening can be automatically adjusted according to the change in driving resistance to keep the driving speed stable.

Taking the electronic speed control system of modern cars as an example, it consists of four parts: command switch, speed sensor, ECU and throttle actuator.

The command switch is generally placed on the combination switch, and most switches have three gears: "speed regulation/fixed speed", "disconnect" and "restore". If the switch is pressed and not moved, the vehicle speed will increase continuously. When the switch is released, the vehicle speed at this time is the set speed of the speed control system.

The speed sensor is connected to the speedometer drive device, and its output signal is directly fed back to the ECU.

The ECU is the center of the speed control system, where the smoothest acceleration and deceleration of each vehicle model are programmed by the designer. According to the command speed, actual speed and other input signals, the ECU generates an output signal after data processing to drive the stepper motor to control the throttle opening.

The electric throttle actuator is generally controlled by a stepper motor, which adjusts the throttle opening according to the ECU's instructions. The throttle position is fed back to the ECU by a sensor. Once the speed control system is turned on, the throttle is "locked". When the vehicle resistance increases (uphill) and the vehicle speed decreases, the throttle opening is controlled to increase, and vice versa, so that the vehicle can maintain a certain speed.

trinamic

Germany's TRINAMIC stepper control chip and driver chip have been widely used in aircraft instruments and automobile instruments in Western countries. The main ones used are TMC428, TMC246 and TMC223 TMC246 internal structure Gavy 13812617052 sunny_8409@sina.com