sMotion from ZF adapts damping forces precisely to the corresponding driving situation while initiating rapid vertical movements of each individual wheel, thus actively lifting the vehicle to ensure optimal roadholding performance while enhancing the driving experience.
The system’s damper technology is now incorporated in two new models of a German premium manufacturer.
Combining dynamic properties with comfort in automotive chassis applications has often been challenging. sMotion has made this easier for automakers as the pitching and rolling manoeuvres inevitable in dynamic steering, braking and acceleration have been virtually eliminated.
“Our fully active sMotion chassis system can almost completely prevent vehicle body movements in certain driving situations,” explains Dr. Peter Holdmann, member of the board of management at ZF and head of the chassis solutions division. “At the same time, the comfort characteristics of vehicles equipped with sMotion increase significantly.”
Two new Porsche models, the Panamera and Taycan, make use of part of ZF’s sMotion active suspension system. Each features Porsche’s “Active Ride” air suspension which uses sMotion’s damper and valve technology.
The sMotion active chassis system is based on ZF’s adaptive damping system CDC (Continuous Damping Control) with two external valves, each of which independently regulates the compression and rebound direction of the damper. Damping pressure is optimally adapted to the respective driving situation, an important quality for driving comfort and dynamics.
sMotion goes a step further using an oil pump to actively move the wheel suspension via the piston rod. The electronic control system can neutralise the effect of road unevenness on individual wheels. It is also able to compensate for or even counteract the wheel height when cornering – during acceleration and braking, for example.
sMotion is particularly powerful during dynamic driving manoeuvres. A sharp steering movement to the right would normally cause a conventionally damped vehicle to “tilt” to the left. Passenger cars equipped with sMotion automatically adjust the cornering inclination to the speed. Thus, the vehicle’s driving behavior takes on a ‘hover mode’. For example, a vehicle equipped with sMotion can use the active damper system to elevate a vehicle by as much as eight centimeters within half a second. This allows the control electronics, also developed by ZF, to hold a passenger car weighing three tons almost horizontally on the road up to a cornering force of one g.
This wheel-specific active body control, which does not use stabilisers, has significant potential in terms of comfort. If vertical movements of the vehicle body are prevented, so-called “motion sickness” can be potentially eliminated.
“Our system virtually eliminates motion sickness, which today primarily affects passengers reading or watching films while traveling,” explains Thomas Kutsche, vice president engineering product line suspension at ZF.
The calming of the vehicle body can be increased even further, for example, if information on road conditions such as bumps or potholes are known, the system can compensate for these in a targeted manner. If automated and autonomous driving continues to increase in practice, this chassis characteristic becomes increasingly valuable for all vehicle occupants.
With sMotion, ZF is adding to its product portfolio for passenger car steering, braking and chassis. With these electronically controlled actuators, ZF can influence the complete longitudinal, transverse and vertical dynamics of vehicles, providing an overall software-controlled system.
In the future, the combination of these technologies will lead to networked chassis systems that can be coordinated holistically with the ZF cubiX software.
“We can support manufacturers not only with the components, but also with software driving functions for the overall system,” adds Holdmann.
Photo credit: ZF
