BWI Group launches new adaptive engine mount technology
The Mercedes-AMG E 63 S adopts second-generation system to combine control and refinement
The 2017 Mercedes-AMG E 63 S uses second-generation Magneto Rheological (MR) Powertrain Mounts from BWI Group, the advanced chassis technology supplier, to enhance control of its 604bhp bi-turbo V8. The adaptive engine mounts combine effective control of powertrain motion with good attenuation of noise and vibration, simultaneously improving vehicle stability and interior refinement.
“Unwanted powertrain movement can hamper vehicle handling by intermittently reducing tire contact loads at the road surface, especially during large torque transients or on bumpy roads,” explained Tim Schlangen, BWI Group’s Mounts Engineering Manager. “Vehicle manufacturers sometimes have to compromise suspension settings to account for this, or use stiffer mountings, which introduce undesirable NVH side effects. Our Gen 2 MR mounts use real time control to provide the optimum damping characteristics at all times, without either of these compromises.”
Extensively proven in adaptive dampers since 2002 and powertrain mounts since 2009, BWI Group’s MR technology uses a damping fluid containing iron particles. When a magnetic field is applied by an electrical coil, the particles become aligned, increasing the fluid’s resistance to flow almost instantaneously; the stronger the magnetic field, the stiffer the system becomes.
The original Magneto-Rheological (MR) Powertrain Mounts were configured for premium sports car applications, preventing large transient powertrain events in the frequency range 2-22 Hz from reaching the chassis. The new Gen 2 design retains this capability while also providing isolation from smaller amplitude movements in the range 30-150 Hz that is critical for comfort, enabling the technology to be applied to vehicles such as the new AMG model where superior levels of refinement are required.
The frequency range has been extended on the Gen 2 mount by the inclusion of a decoupler system that creates a secondary path through which the MR fluid can pass when necessary, reducing mount stiffness. Additionally, internal hardware improvements give a faster response and changes in the control software have increased functionality.
The Gen 2 Magneto-Rheological (MR) Powertrain Mounts also enable the use of CO2-reduction strategies such as engine downsizing, cylinder deactivation and stop-start, all of which can introduce NVH challenges for conventional, passive powertrain mounts. In the case of the AMG E63 S, the V8 deactivates four of its cylinders at times of low power demand, to give enhanced fuel economy.
“Our adaptive powertrain mounts were successfully applied to the Mercedes-AMG C 63 S launched in 2015,” said Didier Gigandet, BWI Group Product Line Manager. “Our team has since introduced the Gen 2 mounts to the market in around half of the time that is expected for such a technology.