They are motor mounts by definition as they are the only thing that holds up the engine. No question there.
They are also pretty good vibration dampers. The inclusion of the spring allows the support and damping functions to be separated and that allows considerably more optimization than is possible in more traditional designs that rely on a visco-elastic material for both and really let you optimize anything but the production cost.
I designed something very similar years ago for a graduate project. The Prof had invented and prototyped and electric generating furnace: https://www.google.com/patents/US4262209
which used a 1 cyl engine……and vibrated itself and its rubber mounts across the floor. The heart of the problem was that the natural frequency of the system was way too high (aka way to close to the engine’s operating frequency) which allowed way to much energy to be transferred to the floor. The solution was to support the engine on a spring/damper system that oscillated about an order of magnitude below even the cranking frequency….. and transmitted about 1% the vibration energy that the original design transmitted.
The Ferrari flat crank engine, like a 4 cyl is inherently balanced to the 2nd harmonic ( kind of rough) vs the Ferrari 12s that like a straight 6 are inherently balanced to the 3rd (very smooth) harmonic so by Ferrari standards the V8 cars run pretty rough. US V8s do a little better by using a 90 degree crank to allow them to damp the 3rd harmonic at specific rpm ranges but that costs hp, which is a trade off Ferrari wasn't willing to make nor where they willing to accept the vibration the V8s where making…..so they spent money on motor mounts that included a better damping system so even thought the engines were rough no one would ever know it and they'd feel like Ferraris
Mark as always you never fail to dissapoint, A+ (of course none of us is married to him either,
Is it just us engineers that sit around thinking of these things and find them not only fascinating but worth the research?
Mark pretty much nailed it
I haven't sat down and run the numbers yet but I was wondering about the cases where the dampers are replaced with solid mounts. now the entire vehicle is the mass that has a new natural frequency and the suspension is pressed into service for two functions. how does that effect the ride, handling etc.. There is also the gearbox to consider as well, the shafts run parallel to the crank and have their own harmonics.
the only downside to this setup is that the drivetrain must power the wheels on the ground and thus the TQ causes the engine assembly to rotate and will missalign the shifter rod. though this is more an issue on engines that have considerably more TQ then stock. Reverse is is a great example of watching the engine twist on it's mounts.
in anycase I found it to be a novel way to handle the harmoincs of the flat crank design. now to design/improve the mount to handle the increased TQ of the large displacement and forced induced engines.
oh, and the woven steel mesh is also a cushion with a very low natural frequency, I'd gather that's the failed part in normal cycles aside from a broken or rusted unit. that part is specific to rotating machines over 2k rpm per Vibrachoc.
Most all the info I've dug up came from Vibrachoc. I'll be honest that I hadn't given the part much thought and when I did it was one of those light bulb moments and I went, "I know where I've seen and used this before" I had never really thought about it in an application for road cars. heavy equipment, buildings, transport vehicles for volatile and dangerous cargo, etc.. sure.
maybe as a consequence of getting older I just don't feel like jiggling my teeth loose when out for a spirited drive, or having to collect hardware as it falls off the car! maybe I need to stop driving the 'ol benz for a bit... nahh fast and smoooooth is the way to go, now to find the buckets of money to make it so.