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READING THAT Mercedes-AMG will feature second-generation magneto-rheological engine mounts brings back memories of a college summer job and later of deliberately pausing a tad in certain shifts with Ferrari’s traditionally gated manual gearboxes.
Memory is funny that way; it’s twofers. And, appropriately, I’ll hold the memories off until tomorrow’s Part 2. Today in Part 1, I’ll focus on the cleverness of engine mounts.
The Mercedes-AMG E 63 S is powered by a twin-turbo V-8 producing 603 hp at 5750 to 6500 rpm and a hefty 627 lb-ft. of torque extending from 2500 to 4500 rpm. According to the factory, this will propel the E 63 S from 0 to 60 mph in 3.3 seconds, with a top speed purposely limited to 186 mph (the magic 300 in km/h).
What’s more, the car is super luxurious, and this is where the second-generation magneto-rheological engine mounts play a role.
In the old days, i.e, during the last century (and doesn’t that sound quaint?), engine mounts were no more than a couple of steel plates sandwiching a wad of rubber. The point of the rubber was to minimize the engine vibrations getting transmitted to the rest of the chassis and giving the occupants a vibra-massage.
Anyone who has ever driven a racecar featuring solid engine mounts knows what I’m talking about.
The rubber wads on production cars got enhanced in today’s engine mounts, the most advanced of which display magneto-rheological properties. That is, the mounts are adaptive to conditions, akin to a suspension’s adjustable shock absorbers, through fluid flow that’s varied by electromagnetic control. (Rheology is the study of flow, to be discussed tomorrow in that summer job tale.)
Similar magneto-rheological technology was applied to engine mounts, the first generation specifically countering low-frequency large-amplitude rumble in the 2 to 22 Hz range.
Of its latest variation, BWI says, “Gen-2 retains this capability while also isolating the chassis from smaller-amplitude movements in the range 30–150 Hz. This is the range that is critical to refinement.”
Quite an achievement: refinement in a car reaching 60 in 3.3 seconds and touching 186 mph.
Part of this refinement in NVH (noise, vibration, and harshness) is attributable to magneto-rheological technology. Tomorrow, I’ll share my brief employment as a Summer Staff Rheologist, sort of, and why I had to lose a tick in accelerating certain gate-shifted Ferraris. ds
© Dennis Simanaitis, SimanaitisSays.com, 2017