The automobile suspension and shock absorption system is quite excellent. It has a significant impact on the vehicle's riding experience and consists of two main components: the spring and the shock absorber.
The Spring
The spring is responsible for supporting the vehicle's body mass. While the vehicle is in motion, it compresses or expands in response to road undulations, converting these movements into vibrations of the vehicle body.
- Soft springs have a long stroke and a low natural frequency.
- Stiff springs have a short stroke and a high natural frequency.
The Shock Absorber
The function of the shock absorber is to provide damping, enabling the amplitude of the vehicle body's vibrations to decrease rapidly over cycles. The commonly used hydraulic twin-tube shock absorber has two main internal parts:
- An oil reservoir chamber, which is filled with gas in the upper part and engine oil in the lower part.
- A working cylinder that contains damping valves and one-way valves.
During the compression and rebound phases, the engine oil flows along a specific path to achieve the shock absorption effect.
Functions of the Shock Absorption System
The shock absorption system plays a prominent role, with the following key functions:
- Enhancing driving safety: It ensures that the wheels remain in contact with the road surface, thereby guaranteeing the vehicle's braking and steering performance.
- Improving riding comfort: It safeguards the safe operation of various vehicle components. Additionally, the spring can provide sufficient support regardless of the vehicle's load.
Types of Shock Absorbers
There are various types of shock absorbers, each with distinct structures and working principles:
- Gas-charged shock absorber: It has a sealed air chamber at the lower part of the cylinder, which is filled with high-pressure nitrogen. The working piston is equipped with a compression valve and an extension valve, whose channel cross-sectional areas change with the piston's movement speed.
- Adjustable-resistance shock absorber: It typically uses an air spring with variable stiffness as the elastic element. By adjusting the air pressure, the throttle hole diameter of the oil is changed, thereby altering the damping stiffness.
- Hydraulic shock absorber: It relies on the piston moving inside the cylinder. The oil in the housing repeatedly flows from one inner cavity to another through narrow pores. The damping force is generated by the friction between the oil and the inner wall of the cylinder, as well as the internal friction of the oil molecules.
Advanced Shock Absorption Technologies
In addition to the basic types mentioned above, there are several advanced shock absorption technologies:
- Air suspension system:
- Automatic level adjustment: It can automatically adjust the vehicle's level, ensuring the vehicle always maintains the optimal posture.
- Height adjustability: It allows the vehicle's height to be adjusted to meet different driving needs.
- Speed-sensing function: It can automatically adjust the vehicle's body height based on the driving speed.
- Shock absorption damping adjustment: It can adjust the shock absorption damping to provide a more comfortable riding experience.
- Structure: It is composed of an air spring and an air damping control valve. By adjusting the compressed air inside the airbag and the flow resistance of the hydraulic oil, it achieves precise control over the suspension's stiffness and height.
- Electromagnetic suspension system:
- In essence, it is an electromagnetic shock absorber used in conjunction with a coil spring. The coil spring absorbs the kinetic energy from bumps and converts it into elastic potential energy. The shock absorber dissipates this elastic potential energy in the form of heat energy by doing work through its internal damping force, thereby maintaining the stability of the vehicle body.
- DCC Adaptive Suspension System:
- It adjusts the working characteristics of the hydraulic shock absorber through electronic control. It can dynamically adjust the driving mode according to the driver's needs and the overall operating conditions of the vehicle.
- CDC Continuous Damping Control Technology:
- Developed by a subsidiary of ZF, its core component is an electronic control unit (ECU). The ECU receives real-time signals from sensors installed in various parts of the vehicle, calculates the optimal shock absorption damping settings, and adjusts the oil flow rate by changing the opening degree of the variable damping valve, thereby altering the damping force. The adjustment frequency can reach several hundred times per second, and this technology is widely used by many automobile brands.
