BILSTEIN DampTronic X: From valve concept to OE production
A valve that adjusts the damping force of a shock absorber within milliseconds is a technical challenge. Manufacturing it in a way that ensures consistent reproducibility on a large scale is another. With BILSTEIN’s semi-active shock absorber technology, DampTronic X, both of these challenges came together. And even were joined by a third: with Porsche as the first OE customer, the new system not only had to be tailored to the new 911 generation (992), but also had to be industrialised for the first time. And all this in a newly built plant, whose production environment was still under construction at the time.
How quickly must a modern damper respond? Ideally, faster than the driver is able to consciously perceive a change in the road surface or driving conditions. This is a particularly demanding task, especially in high-performance sports cars. On uneven roads, the suspension should transmit as little disruptive movement as possible to the bodywork. When turning, braking or accelerating, however, it must immediately generate stabilising forces. The greater the desired range between comfort and driving dynamics, the faster, more precise and more variable a semi-active damper must be able to react.
This is the requirement that led BILSTEIN to develop its semi-active suspension technology, DampTronic X, in which sensors detect the movements of the wheels and body, the control unit calculates the required damping force, and the valve implements the setting within milliseconds.
A new technological approach
Long before DampTronic X, BILSTEIN already had extensive experience with electronically adjustable dampers. The tried-and-tested DampTronic I system, for example, was used for many years in high-performance vehicles, including Porsche sports cars.
With ever-increasing demands on response and adjustment times, as well as control dynamics, a new technological approach became necessary. “The DT1 valve system worked superbly for many years,” recalls Sebastian Dirmeier, who is responsible for various R&D and Porsche projects at BILSTEIN. “However, with the increasing demands on dynamics and control speed, the technological limits had been reached. The next step in development required a fundamentally new approach. The aim was to significantly increase control dynamics compared with the previous DampTronic I system, while at the same time further expanding the possibilities for vehicle-specific tuning.”
Sebastian Dirmeier “The great advantage of DampTronic X is the range of settings it allows us to achieve. This enables us to deliver a very high level of comfort. At the same time, the system can provide the damping forces required for a sporty driving style within milliseconds.“
BILSTEIN’s advanced development team therefore began by developing a new valve system, initially independently of any specific customer project. “At the heart of this development is an internal pressure-limiting valve that operates with pilot control in both the rebound and compression stages, thereby offering significant advantages over competitors’ solutions,” explains Christoph Schmidt, who currently leads cross-customer development in BILSTEIN’s advanced development department.
The result is a combination that is crucial for a modern high-performance sports car: performance, comfort and driving stability. The system thus enables a particularly wide range between soft and hard settings in both the rebound and compression stages. Both settings can be adjusted independently of one another. This allows the damper to respond very precisely in different driving situations.
A further advantage is the exceptionally fast response: the valve reacts particularly quickly to inputs and immediately adjusts the damping force to suit the current requirements.
BILSTEIN’s pre-development project becomes an OE production project
Although the underlying technology was developed in-house at BILSTEIN, the company subsequently worked with Porsche to bring about the first production application. The stated aim: the new generation of the 911 was to offer even more dynamic handling while also providing a wide range of driving characteristics, from everyday practicality to highly sporty performance. This is entirely in line with Porsche’s commitment to achieving best-in-class performance in the areas that matter most to customers.
“The great advantage of DampTronic X is the range of performance it allows us to deliver,” explains Dirmeier. “This enables a very high level of comfort to be achieved. At the same time, the system can provide the damping forces required for sporty driving within milliseconds.”
“Due to the complexity of the valve system, it was decided that the pre-development team would also take charge of the production series launch and subsequent support for the valve systems,” explains Schmidt.
Porsche as a development partner and first OE customer
The decision to opt for DampTronic X marked the start of joint further development towards a specific vehicle application. The system, developed by BILSTEIN, had to be adapted to the architecture, handling characteristics and character of the new Porsche 911.
This involved regular coordination between the development teams as well as driving tests on various test tracks. Findings from testing and road testing programmes were continuously incorporated into the ongoing development. “Discussions were particularly intensive right at the start of the project,” reports Dirmeier. “We met regularly on site to discuss the state of development together. Our driving test engineers and our colleagues from Porsche also met at test tracks around the world to fine-tune the system step by step.”
“The feedback from our customer Porsche was crucial in enabling us to translate the findings from the test bench into vehicle behaviour. The parallel development of the new Porsche model range and the new BILSTEIN DTX valve created synergies that helped us to implement further functions and further improve the DTX valve,” says Schmidt.
The long-standing collaboration between Porsche and BILSTEIN proved to be a key advantage in this regard. BILSTEIN was familiar with the brand’s requirements and the characteristics of the previous model. Porsche, for its part, was working with a partner who understood both the valve technology and its effect on the vehicle as a whole.
Initial industrialisation on several levels
This is how BILSTEIN’s preliminary development work led to a solution tailored to the Porsche 911. For series production, DampTronic X also had to be manufactured reliably and reproducibly to the required quality standards. This marked the start of another major challenge for the project: the initial industrialisation of the new valve system.
Simply producing an existing damper on an existing production line was not enough: DampTronic X required new manufacturing processes, new components and completely new plant technology.
At the same time, development was not yet complete. “Of course, there were always changes during this complex process,” says Sebastian Dirmeier. “We continue to develop the system in collaboration with the OEM, gaining a deeper understanding of it and optimising it continuously.”
The solution lay in close coordination between the departments involved. Findings from development and testing were continuously incorporated, while at the same time the new manufacturing processes and equipment were brought to production readiness. Experience gained with Porsche and other semi-active systems from Bilstein provided a solid foundation for this.
However, the complexity of the project was characterised by a further distinctive factor: the industrialisation of DampTronic X also served as the inaugural project for the newly established BILSTEIN plant in Sibiu, Romania.
“Industrialisation, carried out together with our new colleagues from Romania, was a major challenge. At the same time, it laid the foundations for successful collaboration on subsequent industrialisation projects,” says Schmidt.
DampTronic X as the inaugural project for the new BILSTEIN plant in Sibiu
At the start of the project, there was as yet no established production environment in Sibiu. The new production hall had to be completed in time so that the equipment procured specifically for DampTronic X could be delivered and connected. At the same time, the infrastructure and production processes had to be set up and fine-tuned.
At the same time, technical development continued. Changes to the product might have required adjustments to processes and equipment, whilst the production ramp-up had to meet Porsche’s deadlines and quality requirements. Development, industrialisation, the plant and the customer therefore had to work together particularly closely.
“Porsche is known for always pushing the boundaries of what is technically feasible in vehicle development,” says Dirmeier. “For us at BILSTEIN, this means meeting the highest standards, both in product development and in manufacturing.” Collaboration on an equal footing was crucial in this regard: “Together, we were able to develop solutions to these demanding challenges that meet Porsche’s requirements in every respect.”
From new technology to an established solution
The successful start of series production in the Porsche 911 also laid the foundations for further applications. There was no need to redevelop the valve technology from scratch for subsequent projects. Damper dimensions, specifications and vehicle-specific tuning could be adapted to the respective application.
Its successful use in the Porsche 911 formed the basis for numerous other applications. Today, DampTronic X is used, amongst others, in all Aston Martin sports cars, the Maserati MC20 and the BMW M5.
What had begun as a BILSTEIN pre-development project had thus become a production-proven technology that could be applied to other demanding vehicle projects.
