Fully hydropneumatic reactive suspension for road cars

[Honda Porsche fan]

Could a automaker produce a car with the suspension similar to the 1993 Williams FW15C but updated for the 21st century for a production road car?

Is there a way to make it durable/reliable as a daily driver? I would assume the hydraulic fluid lines would need to be a rust proof stainless material?

What about the hydraulic fluid? Can it go long periods of time without being flushed out and replaced?

I was thinking of a limited special edition Corvette C8 or a Gordan Murray designed supercar in limited numbers. Or, someday a mass produced Honda or Toyota with it.

Learn from the aerospace industry and defense contractors (BAE Systems, Boeing, GE, Lockheed Martin, Raytheon)

A Conversation with an F-35 Maintainer about the Impact of the New F-35 Actuator System on Maintenance...

"Simplified hydraulics like in the F35 jet - EHAS electro hydrostatic actuation system. Self-sustained hydraulic systems, everything is self-contained. You’ve got your own hydraulic systems. You got your own actuators."...

https://sldinfo.com/2010/08/a-conversat ... intenance/

https://www.eaton.com/content/dam/eaton ... ochure.pdf

[Hoffman900]

The Williams system was originally derived from a system for ambulances, just re-adapted and improved upon for motorsports. Lotus tried it first in 1983.

BMC used a Hydrolastic suspension on the Minis starting in 1964.

There have been other air and hydraulic solutions over the years, from Cadillac to Mercedes.

Nothing is new out there.

[Greg Locock]

Lotus was going to fit full active suspension to 200 Corvettes in 1988 roughly, but the project got canned shortly before it was due to get serious. I don't know why. I saw them in the workshop, never saw one on the track, perhaps that's a clue!

Nissan introduced a low bandwidth active suspension in the same timeframe, (SAE paper 901747) and of course you can consider air springs and the like as active if you want to.

The big problem at the time was that you really want to know what the road profile is ahead of you, easily done now.

These days I wouldn't bother, MRD gives you most of the benefits and none of the hassle.

[Honda Porsche fan]

If I'm not mistaken, but wasn't the Williams FW15C part semi-active and reactive?

In order for a suspension to be true fully active wouldn't it need to be more like A.I. artificial intelligence that can predict ahead of time the road surface like putting lasers on the front grill that scans the road surface before the car rides over it?

I don't know if there has ever been a true fully active suspension. The most advanced suspensions in auto racing and production seem to be semi-active and reactive.

[Greg Locock]

Yes the Lotus system was full active.

[tpe]

Citroen had a semi-active hydraulic suspension with its last XM.
Mercedes had a similar system but I don't remember the model/year and I also don't remember if it was a combined air springs/dumpers or just air-suspension.
Both of them around the 1990s.

[Honda Porsche fan]

With regards to the hydraulic fluid lines. Would the fluid need to be replaced often? What type of fluid can be used?

[saviour stivala]

Oil-based fluid dyed red, essentially the same as brake fluid, but not the same. So it is not the brake fluid, although it also operates the rear brake-by-wire system.

[bigblue]

Off the top of my head, but just FYI the Lotus system used Moog actuators I believe. There was video of a conventional Esprit and an active one going through a slalom, with the active one completely level. They could even make the car lean into corners if desired. I also seem to remember the system on the 99T being given a thorough workout by Nakajima getting airborne after a collision at the start of a race (sensors - "where's the ground, where's the ground ? ... Oh &*£^! There it is!). I haven't searched but there must be a bunch of info on the web about the system. Lotus also were looking at anti-noise (for refinement), and also some noise enhancement, and had a Citroen AX they could make sound like a V8

[Tommy Cookers]

Could a automaker produce a car with the suspension similar to the 1993 Williams FW15C but updated for the 21st century for a production road car? ....

afaik
the Williams system was 4 (electrohydraulically-actuated) intelligent spring mounts - powered from a hydraulic main

intelligent spring mounts on a road car wouldn't need hydraulic actuation (though the F-35 control surfaces do)
4 such (electromechanically or electrically actuated) intelligent spring mounts powered from an electrical main ...
and even recovering energy ...

[saviour stivala]

From a 'control' system point of view (key performance required) an electrohydraulic system is preferred over an electropneumatic system packaging wise. As the case with aircraft the servo-valve is the key solution in the electrohydraulic control system. it can reflect small electronic inputs with proportional change in pressure output. 'MOOG is the company that universally make the servo-valve for F1 use -- MOOG-VALVE. A control system control is achieved via DC output from ECU controlling a solenoid inside the servo-valve.

[Honda Porsche fan]

From a 'control' system point of view (key performance required) an electrohydraulic system is preferred over an electropneumatic system packaging wise. As the case with aircraft the servo-valve is the key solution in the electrohydraulic control system. it can reflect small electronic inputs with proportional change in pressure output. 'MOOG is the company that universally make the servo-valve for F1 use -- MOOG-VALVE. A control system control is achieved via DC output from ECU controlling a solenoid inside the servo-valve.

What's the differences between the electrohydraulically-actuated vs electromechanically-actuated in their physical sense and also in performance? Any advantages and disadvantages between the two when it comes to the handling of a car, how it responds to bumps, quick turning, acceleration and deceleration etc? Could a experienced driver and even a novice feel the difference between the two?

If a designer/engineering team for an auto company is given a high budget to work with to design a suspension system that is active for both road and track use which option would be superior?

[Honda Porsche fan]

Could a automaker produce a car with the suspension similar to the 1993 Williams FW15C but updated for the 21st century for a production road car? ....

afaik
the Williams system was 4 (electrohydraulically-actuated) intelligent spring mounts - powered from a hydraulic main

intelligent spring mounts on a road car wouldn't need hydraulic actuation (though the F-35 control surfaces do)
4 such (electromechanically or electrically actuated) intelligent spring mounts powered from an electrical main ...
and even recovering energy ...

hmmm, today if F1 teams were allowed active suspension would A.I. artificial intelligence be used to control the suspension?

Also, something like this...

High-performance embedded computing (HPEC). The Automotive Supercomputer...

https://www.electronicdesign.com/techno ... ercomputer

[Greg Locock]

If a designer/engineering team for an auto company is given a high budget to work with to design a suspension system that is active for both road and track use which option would be superior?

For any feasible budget MRDs offer so much of the performance for so little hassle you'd use MRDs and better tires (which are far more important than suspension gizmos) and better brakes.

Designers have nothing to do with it.

[saviour stivala]

From a 'control' system point of view (key performance required) an electrohydraulic system is preferred over an electropneumatic system packaging wise. As the case with aircraft the servo-valve is the key solution in the electrohydraulic control system. it can reflect small electronic inputs with proportional change in pressure output. 'MOOG is the company that universally make the servo-valve for F1 use -- MOOG-VALVE. A control system control is achieved via DC output from ECU controlling a solenoid inside the servo-valve.

What's the differences between the electrohydraulically-actuated vs electromechanically-actuated in their physical sense and also in performance? Any advantages and disadvantages between the two when it comes to the handling of a car, how it responds to bumps, quick turning, acceleration and deceleration etc? Could a experienced driver and even a novice feel the difference between the two?

If a designer/engineering team for an auto company is given a high budget to work with to design a suspension system that is active for both road and track use which option would be superior?

What I was talking about was the electrohydraulic control system/s used in formula one. It was FERRARI first trying to shift gears hydraulically. It was Lotus first trying to control suspension electro/hydraulically. Although active suspension was banned, the electrohydraulic control system was retained. When teams were trying to shift gears electro/hydraulically (semi automatic gearshift) Tyrrill was the one that developed a pneumatic system, but was soon faced-out as hydraulic proved a better solution.