The springs in a car act as elastic components that support the vehicle and cushion vibrations. But if there were only springs, when encountering large bumps or leans, the vehicle would bounce uncontrollably, like a rubber ball, which no passenger could tolerate. That’s where shock absorbers come in. The oil or compressed gas inside the shock absorber quickly dissipates this reciprocating motion through the damping effect of fluid movement, ensuring the stability of the suspension and the comfort of the ride.
Conventional oil/Gas-filled shock absorber
Currently, the most commonly used hydraulic shock absorbers are mainly twin-tube shock absorbers. The general structure is shown in the figure below, consisting of a piston, a cylinder, and multiple one-way valves. The extension valve of this type of shock absorber is much stiffer than the compression valve, so the damping force during compression is not very high, but the damping force during extension is significantly greater. This helps eliminate the tendency of the suspension to keep bouncing back up, achieving a damping effect. Conventional hydraulic shock absorbers are also the most widely used in vehicles today, featuring a relatively simple structure and being easier to maintain. It’s important to regularly check these shock absorbers; if the cylinder seal is compromised and the shock absorber leaks oil, it will lose its damping capability, and timely replacement will be necessary.
Gas-filled shock absorbers share a similar basic principle with hydraulic shock absorbers
except that they are filled with high-pressure gas internally(typically nitrogen)The latest car market trends show a simpler structure, generally using a single-tube design. Gas-filled shock absorbers offer more ideal working conditions, but they require higher standards for sealing and gas-filling processes, and are mostly used for aftermarket modifications.
Damping-adjustable shock absorbers
As the name suggests, the damping of these shock absorbers can be adjusted, and they are divided into conventional damping-adjustable shock absorbers and electronically controlled variable damping shock absorbers(Usually, adjustable damping shock absorbers that use electromagnetic control for the car’s channels require relatively complex electromechanical devices, some of which also need auxiliary hydraulic systems. Their structure is complicated, the cost is not low, and they are difficult to popularize in ordinary models.
Electronically controlled/magnetorheological fluid shock absorbers
In comparison, electronically controlled magnetorheological fluid shock absorbers are more flexible in use, and also smaller and lighter in size. Moreover, magnetorheological fluid/shock absorbers, due to their more stable working condition compared to electrorheological fluid(MRF)shock absorbers, have quietly become the mainstream technology and are already equipped in many vehicle models. Similarly, electromagnetic shock absorbers can also be manually set for adjustment, or the vehicle can automatically adjust the damping of the shock absorber based on collected dynamic information to achieve dynamic control. The principle of magnetorheological shock absorbers is mainly to fill the shock absorber with magnetorheological fluid and arrange electromagnetic coils. The magnetorheological fluid can change from a highly fluid liquid to a viscoplastic substance under the influence of a magnetic field(ERF)like changing from water into putty instantly(, and this change is controllable, rapid, and reversible, thus providing strong adaptability.), and this change is controllable, rapid, and reversible, thus providing strong adaptability.
Apart from the types and characteristics of shock absorbers, in reality, their matching relationship with elastic components and suspension parts, as well as factors such as the vehicle’s center of gravity distribution, all play a decisive role in the vehicle’s dynamic performance. Handling is indeed a very complex subject, and we will continue this series of topics to explore how these factors influence performance.