What are the different damping systems?
Electronically controlled damping systems
When using conventional dampers, only one damping characteristic can be realized, which basically requires a compromise between comfort and sportiness of the vehicle behavior. Electronically adjustable dampers make it possible to resolve this conflict of objectives by integrating hydraulic switching or control valves.
Different versions of adjustable damping systems are available. In a basic version, it is possible to switch manually between two predefined characteristic curves, e.g. from "Normal" to "Sport". The selection controls a solenoid valve that regulates how much oil can flow out and thus influences whether the damper acts softer and more comfortable or sportier and firmer.
Dampers with infinitely variable valves offer more flexibility and better adaptation to road conditions and driving behavior. This allows the vehicle manufacturer to realize almost any number of gradations of damping characteristics and thus, for example, offer other modes such as "Comfort" and "Sport Plus" in addition to "Normal" and "Sport".
In addition, the continuously adjustable valves offer the option of actively adapting the damper behavior to the respective driving situation or even acting with foresight. Based on navigation map, sensor or camera data, the damping system can be adapted to the road conditions in a highly dynamic and precise manner. As each damper can be controlled individually, this increases driving stability and safety.
The more sophisticated the damping system, the better the balance between driving safety, comfort and dynamics can be achieved.
Internal + external valve solutions
Internal valves are integrated into the damper tube and enable optimized packaging, as less installation space is required on the outside of the damper. However, the internal design can have a detrimental effect on the overall length or stroke of the damper. Depending on the application, the demanding space requirements inside the damper tube may also make it necessary to compromise on valve performance.
External valves are mounted on the outside of the damper tube. This is associated with increased requirements for resistance to environmental influences and an increased installation space requirement. At the same time, however, the overall length of the damper is reduced. There is also greater design freedom with regard to valve performance.
Differentiation between single-valve and twin-valve dampers
Single-valve dampers have - as the name suggests - a solenoid valve. This either regulates only one direction of movement of the damper or can also be used to regulate the rebound and compression stages. However, the prerequisite for this is usually the rectification of the flow for the valve, which is made possible by special damper designs (three-tube dampers), for example. With single-valve dampers, the compromise must be accepted that one valve controls both damping directions and therefore the valve and damping characteristics of both directions cannot be designed independently of each other.
With dual-valve dampers, this compromise is resolved by installing one valve for the rebound stage and another for the compression stage. The advantage of dual-valve solutions is that the two valves can be adjusted more precisely for their use in rebound or compression.
Pros & cons
Today, electronically controlled damping systems are already available in basic versions for mid-range vehicles at attractive prices. Depending on the driving situation and behaviour, safety can be increased and road holding optimized.
These effects are clearly noticeable with semi-active damping systems, which individually regulate the rebound and compression stages via infinitely variable valves and are able to achieve an optimum balance between dynamics and comfort. These systems are more complex and cost-intensive, but offer a high level of driving safety.
Solutions
Our know-how specifically for your application
RAPA Automotive offers a wide range of options for damper switching and control valves: from cost-optimized platform developments to individual, customer-specific valve solutions.
The customer benefits from developments based on many years of expertise in the field of hydraulic shock absorber valves.
Wide range of options
RAPA Automotive's expertise ranges from space-saving, internal damper valves to solutions for external mounting and from valves with double-sided flow to precise, single-sided flow control valves.