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Doug Carson, Senior Advisor to BWI Group in Q&A session

Doug Carson has been involved with MagneRide suspension system since 2005, as Chief Engineer. He was responsible for the launch of the suspension technology into Europe. Carson later became Chief Technology Officer. In this Q&A, he reflects on MagneRide’s engineering breakthroughs that defined the award-winning suspension systems.

Q: Where did the idea for MagneRide come from?

The concept of using magnetorheological fluid for damping goes back decades. But it wasn’t until the 1990s that the technology became viable for automotive use, thanks to advances in materials, electronics, and control strategies.

MagneRide became a viable alternative and the idea of a valveless damper, controlled purely by a magnetic field and software, was incredibly compelling. It promised levels of control and tuneability that simply weren’t possible with other semi-active technologies.

Q: When did development of the MagneRide really start to take off?

The first big step was around 1995, when MagneRide dampers were put on a Chevrolet Suburban. In the very early trial, the ride quality wasn’t perfect, but the response and authority of the system were there and it showed some real potential.

After experiencing the technology firsthand, teams from Cadillac and Corvette were eager to put it into production. Finally, the first programme went into mass production with the 2002 Cadillac Seville STS.

Q: What were the major technical challenges during development?

This really was a semi-active suspension system like no other so there were a lot of challenges to overcome. Magnetorheological fluid is full of iron particles, which meant we had to rethink materials entirely. We adapted several parts, including gas cups, cylinder tubes and rod guides. We were also developing new control algorithms and adapting to the demands of automotive production.

Q: How did MagneRide stand out from anything else on the market?

With MagneRide, there are no internal valves or complex flow channels. The increase of damping force comes from altering the characteristics of the magnetorheological fluid with a magnetic field. That means faster response times, just  milliseconds, and no moving mechanical components to wear out or fail.

MagneRide makes OEMs’ development faster, more flexible, and more cost-effective. It’s fully software-controlled. You don’t need to manufacture new parts to tune the damper, you just plug in a laptop and adjust the calibration.

Q: How was MagneRide received by the industry at launch?

The system won a string of industry awards: the Popular Science “Best of What’s New” in 1999 and 2002, the 2003 PACE Award.

Besides Cadillac, MagneRide was also installed in Ferrari. That was great validation for us, if Ferrari wanted MagneRide then clearly, we were onto something special. From there, it spread quickly to other major OEMs, including Lamborghini, Audi, Honda, and Ford.

Q: How has MagneRide evolved over the years?

A major area of progress has been the secondary ride, which is the ability to filter out small, high-frequency inputs that affect NVH and comfort. That’s especially important for modern EVs, where cabin noise is low and every bump is more noticeable.

Besides, the fluid is now better performing, the damper architecture is refined, and the control algorithms are much smarter.

We’ve also made the system much more modular and flexible. OEMs can choose full-system delivery, including software, sensors and ECUs, or just the dampers. That flexibility helps OEMs integrate more easily with centralised vehicle architectures and software-defined platforms.

Q: And what does the future hold for MagneRide?

The developments in secondary ride have enabled MagneRide to be applicable to more vehicle segments. The rise of heavier vehicles has also increased the demand for more sophisticated suspension technologies. As a result, MagneRide is now being used on everything from SUVs, hatchbacks, saloons and sports cars.

We’re also working on smarter integration. As vehicles become increasingly software-defined and connected, MagneRide can play a bigger role in predictive control to use data in real time to adjust settings based on the road ahead.

We are also leveraging AI to further accelerate the tuning phase. It means that when we get to tuning on the track, in the real car, the algorithms are already very mature.

Interview with Philippe Germain, Chief Engineer at BWI Group

MagneRide^®, BWI Group’s semi-active suspension technology, is unique in the industry for its use of magnetorheological fluid and its ability to adapt damping forces a thousand times a second. Since its debut in 2002, it’s been the choice of leading performance car manufacturers but as the industry shifts to electric and connected vehicles it is now finding broader applications. We spoke with Phillipe Germain, Chief Engineer at BWI Group, to discuss the latest generation of MagneRide and how it has been designed for the industry’s latest trends.

Q: Let’s start from the top, what is MagneRide and how does it work?

PG: MagneRide is a semi-active suspension system that uses a magnetorheological fluid, which is essentially a damper fluid filled with iron particles. When a magnetic field is applied, those iron particles align within a simple linear orifice, and the aligned particles provide resistance to flow, resulting in a variable damping force. We can precisely and quickly change the damping force to provide high levels of body and wheel control.

Q: How does this compare to solenoid-based semi-active systems?

PG: Solenoid-based dampers use traditional hydraulic fluid flowing through multiple passive and solenoid-actuated valve systems. The result is a damper construction with a significant number of additional components, and which is inherently more complex. MagneRide dampers use fewer components, making it easier to tune and resulting in a more robust solution for NVH and warranty issues.

Q: MagneRide started in performance cars. How has its application evolved?

PG: That’s right. The technology was first adopted by high-performance vehicle manufacturers. They valued the control MagneRide provides for body motion and handling, especially in the 1 to 3 Hz frequency range where handling dynamics live.

But today we’re seeing MagneRide on sedans and SUVs, including electric vehicles, in both North America and China. We’ve made major strides in design efficiency, manufacturing, and supply chain scale, so cost is no longer a barrier. In fact, MagneRide is now comparably priced to solenoid-based systems, which makes it affordable not only for sports models of Lamborghini and Ferrari, but also for other vehicle segments.

Q: How has the industry changed since it was first introduced?

PG: Since MagneRide was first introduced, vehicles have become much heavier. In 2016, the average weight of a car was around 1550kg, this is now closer to 1950kg, a 25% increase and many BEVs are in the 2.5 tons range. This added weight makes controlling the body and suspension very challenging. This is something MagneRide is very good at. Along with more competitive pricing, this advantage is why we are increasingly seeing MagneRide applied to SUVs and BEVs.

Q: Have you adapted the technology for these new applications?

PG: Semi-active damper performance is about fast and accurate sensing and providing fast and accurate damping forces that meet the desired forces. Heavier BEVs require increased damping forces and do so in a more NVH-sensitive vehicle environment.

We’ve introduced several important technological updates to suit the changing requirements of the industry. First, we’ve added wheel accelerometers to more accurately measure suspension movements. This helps us to refine the damping force even more precisely. We’ve also integrated an inertial measurement unit (IMU) to better capture vehicle body dynamics.

Another big improvement is our new bi-directional damper current control solution. It allows us to change the damper’s magnetic flux more accurately, which improves response time and control quality. We’ve also developed a new low-friction rod guide and are working on a low-temperature fluid with more consistent viscosity across a wide range of temperatures.

Specifically for heavy vehicles, we now offer a 52mm piston. It delivers about 80% more damping force than our standard units and gives OEMs a much larger operating envelope to work with.

Q: Why are OEMs looking for a larger operating envelope?

PG: Vehicle dynamacists call it turn-up. It’s the ratio between the maximum and minimum damping force available for a given stroke velocity. MagneRide provides a much broader force range than traditional dampers. This includes providing significant damping force at low velocities, something solenoid-based solutions can’t do.

This is particularly useful for modern vehicles with multiple drive modes. A lot of solenoid systems can’t offer a noticeable difference between comfort and sport modes because they’re limited in their operating envelope. With MagneRide, you really feel the difference. This market-leading turn-up also gives engineers flexibility to tune the vehicle’s character to exactly how they want it.

Q: How does MagneRide simplify vehicle tuning and development for OEMs?

PG: With traditional valve-based dampers, tuning is a hands-on, hardware-heavy process. When we are developing a valve-based damper for a customer, we literally show up with a truck full of different shim stacks and valves to test. We trial different combinations to get the right damping and feel for the vehicle. Every change means disassembling and reassembling the damper, testing it and then fitting it to the test vehicle. So it is a time-consuming task.

With MagneRide, all that tuning is done in software. You plug in a laptop, adjust the control maps, and you’re done. It dramatically reduces development time and cost. And because we provide a control library for customers using their own ECUs, they can get up and running quickly, there is no need to develop low-level controls from scratch.

Q: What is the key performance differentiator for MagneRide?

PG: I’d say the ability to control wheel and body motions independently. In traditional dampers, if you want more body control, you usually sacrifice comfort by stiffening the whole system, including how the wheels respond to high-frequency road inputs. With MagneRide, we can decouple those. That means better ride quality and better handling at the same time, which is something solenoid-based systems really struggle to achieve.

Q: How does this independent control work in real-world driving scenarios?

PG: The system processes inputs from both the road and the driver. It detects wheel movement and driver intentions, such as throttle position, steering input. It then calculates the required damping forces accordingly. For example, when cruising on the highway in a straight line, the vehicle can be optimised for comfort with softer settings. But when the driver enters a corner, the system immediately provides enhanced body control.

Q: So what’s next for MagneRide and BWI Group?

PG: We’re continuing to make the system more modular and accessible. OEMs can buy the full system from us, including software, ECU, sensors and dampers, or they can just use the dampers and provide their own control system. We’re also working on a new modular piston design that supports lower current requirements, which makes integration even easier for customers using their own ECUs.

New Vehicle Project

BWI Group has recently obtained a magnetic fluid suspension project from
a leading Chinese automaker, covering multiple models including sedan, SUV,
and high-performance vehicle, with an annual volume of 400,000 units. The
fourth-generation MagneRide® suspension to be applied in this project is
scheduled to officially start mass production in China in mid-2025.

The prototype vehicle developed by BWI Group, with the magneto-rheological
suspension as the core of its chassis, has achieved a substantial upgrade in
chassis performance. It not only significantly improves the vehicle’s handling
but also performs exceptionally well in multiple dimensions such as comfort
and stability. The high recognition from the leading automaker stems from
BWI Group’s leading technology in the suspension industry and reflects its
benchmark status in China’s chassis and suspension fields.

Superior Value and Performance

The fourth-generation BWI MagneRide® suspension, with its simple structure
and active suspension technology, offers superior handling, comfort, and
safety for vehicles. It provides a better choice for smart chassis upgrade and
the transition to active suspension systems.

When a user driving a vehicle equipped with the fourth-generation BWI
MagneRide® suspension, sensors collect real-time information from the entire
vehicle, wheels, and pedals. The ECU processes this data to achieve
ultra-high-frequency adjustments of up to 1,000 times per second, with a
response speed 5 to 10 times faster than traditional systems. At a vehicle
speed of 100 km/h, the suspension can adjust approximately every 2.5 cm of
travel. With a damping dynamic adjustment range about twice that of other
technologies, it better balances comfort and handling.

In the production and development of car models, MagneRide® suspension
do not require complex valve systems. The hardware is easier to standardize
and universalize, and different damping characteristics can be achieved simply
through software adjustments, making it highly adaptable to various scenarios.
The flexibility in tuning during vehicle development also facilitates subsequent
OTA upgrades. The symmetrical compression and rebound forces provide
fine-tuning capabilities that other suspensions lack, allowing precise
adaptation to minor road surface changes and significantly reducing the
tuning and development cycle.

Cost Reduction and Expansion

As a global leader in suspension and braking systems, BWI Group is
accelerating the mass production of the fourth-generation MagneRide®
suspension in China. With its millions of units production capacity, the
company will leverage economies of scale to significantly reduce the cost of
this world-leading active suspension technology, making it more accessible to
consumers.

BWI Group will continue to expand its production capacity, deepen
cooperation with Chinese and international automakers, promote the
application of magnetic fluid suspension in more vehicle models, and further
empower the upgrade of intelligent chassis systems.