Automotive Suspension Systems: Shock Absorbers, Air Suspension and Key Components Analysis

Automotive Suspension Systems: Shock Absorbers, Air Suspension and Key Components Analysis

   Vehicle suspension systems are at the heart of vehicle safety, comfort and manoeuvrability, with shock absorbers, air suspension and related components playing a vital role. Understanding how they work and what they do has far-reaching significance in ensuring vehicle performance and driving experience.

Shock Absorbers: Guardians of a Smooth Ride

   The Shock Absorber is the most common and indispensable component of a suspension system. Its main function is to dampen the vibrations of the springs. When the vehicle is driven on uneven surfaces, the wheels bounce up and down and the springs compress and extend. Without shock absorbers, the springs will continue to oscillate, causing the body to lurch and become unstable, or even out of control. Shock absorbers, widely used in automobiles, are designed to accelerate the attenuation of vibrations in the frame and body to improve the smoothness of the car's ride.

Working Principle:

   Most shock absorbers are hydraulic dampers. It usually consists of a piston, oil and valves inside. As the wheel moves up and down, the piston moves inside the cylinder, forcing the oil through small holes and valves. Due to the viscosity of the oil and the resistance of the holes, the movement of the piston is impeded, thus converting the vibration energy into heat and radiating it away, effectively suppressing the excessive oscillation of the spring. According to the internal structure and the way of controlling the flow of oil, the shock absorber can be further divided into various types such as single and double cylinder, oil and gas hybrid.

Widely used in automotive suspension systems is the cartridge shock absorber, the shock absorber in the compression and extension stroke can play a role in shock absorption, so it is also called two-way action type shock absorber. Cylindrical shock absorbers can be divided into single and double cylinder shock absorbers, as well as the use of a new type of shock absorber, which includes inflatable shock absorbers and resistance adjustable shock absorbers.

Single-cylinder type

   Compared with the double-cylinder type, single-cylinder shock absorber structure is simple, reducing a set of valve system . It is equipped with a floating piston in the lower part of the cylinder, (the so-called floating that is, no piston rod to control its movement), in the floating piston below the formation of a closed gas chamber, filled with high-pressure nitrogen. Above mentioned as a result of the piston rod in and out of the oil caused by changes in the height of the liquid level through the floating piston floating to automatically adapt to it. In addition to the two types of shock absorbers mentioned above, there is also the resistance adjustable shock absorber. It can be operated externally to change the size of the throttle orifice. Recent cars have electronically controlled shock absorbers as standard equipment, which detect the driving condition by sensors and calculate the optimum damping force by a computer, so that the damping force adjustment mechanism on the shock absorber works automatically.

Double-cylinder type

   It means that the shock absorber has two barrels, one inside and one outside, and the piston moves in the inner barrel. Due to the entry and withdrawal of the piston rod, the volume of the oil in the inner barrel increases and shrinks, so it is necessary to maintain the balance of the oil in the inner barrel by exchanging it with the outer barrel. Therefore, there should be four valves in the double-cylinder shock absorber, i.e., in addition to the two throttling valves on the piston mentioned above, there are also circulation valves and compensation valves installed between the inner and outer cylinders to complete the exchange function.

Hydraulic

   Hydraulic shock absorbers are widely used in automobile suspension systems. The principle is that when the frame and axle do reciprocating relative motion and the piston in the shock absorber cylinder barrel reciprocating movement, the shock absorber shell fluid will repeatedly from the inner cavity through some narrow aperture into another cavity. At this time, the friction between the liquid and the inner wall and the internal friction of the liquid molecules will form a damping force on the vibration.

Inflatable

   Inflatable shock absorber is a new type of shock absorber developed since the 60s. Its structure is characterised by a floating piston in the lower part of the cylinder, and a closed gas chamber formed at one end of the floating piston and cylinder is filled with high-pressure nitrogen. In the floating piston is equipped with a large cross-section O-ring seal, which completely separates the oil and gas. The working piston is equipped with a compression valve and an extension valve that change the cross-sectional area of the channel with the size of its movement speed. When the wheel jumps up and down, the working piston of the shock absorber does reciprocating movement in the oil, so that the working piston of the upper chamber and the lower chamber of the oil pressure difference between the pressure oil is pushed away from the compression valve and the extension valve and back and forth flow. As the valve produces greater damping force on the pressure oil, the vibration attenuation.

Product Use: In order to accelerate the attenuation of vibration of the frame and body to improve the comfort of the car in the process of travelling, shock absorbers are installed inside the suspension system of most cars.

The shock absorber system of an automobile is made up of springs and shock absorbers. Shock absorbers are not used to support the weight of the body, but rather to dampen the shock of the spring's rebound and absorb the energy of the road impact. The spring acts as a shock absorber, turning a "large energy impact" into a "small energy multiple impact", while the shock absorber gradually reduces the "small energy multiple impact". The purpose of shock absorbers is to dampen the bouncing that occurs when the car is driven in bad road conditions. Without shock absorbers, it is impossible to control the rebound of the springs, and the car will bounce heavily when it encounters rough road surfaces, as well as lose tyre grip and traction when cornering due to the up and down vibration of the springs.

Importance:

Improves ride comfort: Reduces bumps and provides a smooth and comfortable ride.

Improves handling stability: Maintains constant contact between the tyre and the road surface, improving grip and steering response.

Extends tyre life: Reduces abnormal tyre wear caused by skipping.

Ensures driving safety: Avoids loss of control due to excessive vibration at high speeds or during emergency braking.

Air Suspension: Intelligent Adjustable Comfort

   Air Suspension is a more advanced suspension system that uses air springs instead of traditional coil springs or steel plate springs. Using an air compressor, an air reservoir, a control unit and a series of sensors, the Air Suspension system is able to adjust the body height and suspension stiffness in real time.

How it works:

     At the heart of an air suspension system is the air spring, which is a sealed rubber airbag filled with compressed air. By increasing or decreasing the amount of air in the airbag, the stiffness (hardness) of the spring and the height of the vehicle can be changed.

Height Adjustment: When the vehicle needs to be raised, the air compressor pumps air into the airbag; when it needs to be lowered, the air is expelled from the airbag. This allows the vehicle to adapt to different road conditions (e.g. raised when travelling over bumps, lowered at high speeds to reduce wind resistance).

Stiffness adjustment: By changing the air pressure in the airbags, the stiffness of the suspension can be adjusted. In Comfort mode, lower air pressure results in a softer suspension; in Sport mode, higher air pressure results in a stiffer suspension.

Auto-Balance: Sensors monitor the body attitude and loads in real time, and the control unit automatically adjusts the pressure of the individual air springs according to the data to keep the body level.

Importance:

Excellent ride comfort: Absorbs road impacts effectively, providing a "magic carpet" ride.

Strong adaptability: Body height and suspension stiffness and softness can be adjusted automatically or manually according to road conditions, vehicle speed and load, improving passability and stability.

Improved load-carrying capacity: Under heavy loads, the air suspension can better support the body and maintain the vehicle's attitude.

Better NVH performance: Helps reduce vehicle noise, vibration and smoothness.

Key Components of Suspension Systems

In addition to shock absorbers and air springs, a complete suspension system consists of a number of important components that work together to ensure the efficient operation of the suspension system:

Control Arm: Connects the wheel to the frame and is a key component in transmitting torque and positioning the wheel in motion.

Ball Joint: Connects the control arm to the steering knuckle and allows the wheel to rotate freely in different directions.

Bushings: Usually made of rubber or polyurethane, they are fitted between the connecting parts to absorb vibration, reduce noise and allow a certain degree of movement.

Sway Bar/Anti-roll Bar: Connects the left and right wheels to limit body roll during cornering, improving stability and handling.

Steering Knuckle: Connects the wheels, bearings, brakes and suspension components, and is a key component in wheel steering and load carrying.

Coil Spring: A traditional elastic element used in conjunction with shock absorbers to support the weight of the body and absorb road impacts.

Summary

    Shock absorbers, air suspension and related components together constitute the "bones and muscles" of the car, and their working principle and role directly affect the vehicle's ride quality, safety and reliability. As automotive technology continues to evolve, suspension systems are becoming smarter and more versatile to meet the growing demands of consumers for a better driving experience. Understanding these core technologies will help consumers to better choose and maintain their cars and enjoy a safer and more comfortable driving journey.