How it Works

Control

Steady state – While the vehicle is going straight at a constant speed, turning at a constant speed or simply standing still, it is in a steady state. 
In Sacli suspensions, the magnitude each sub-suspension responds to roll during steady state cornering is a function of each suspensions roll rate.  Roll rate is a function of the roll moment and roll resistance. 

Assuming the roll centers, track width and C of G are set we can only change the spring (wheel) rates and anti-roll bar rates to adjust the steady state roll resistance for each sub suspension.  If the roll suspension rolls more due to lower roll resistance (softer springs) the wheel will gain camber.  If the dive suspension rolls more due to lower roll resistance the wheel would lose camber.  The steady state roll resistance ratio between roll and dive suspensions decide the resultant camber loss or gain at the wheel per degree of body roll.

If the vehicle has down force then the amount the vehicle sets (ride height reduction) going straight at a given speed is a function of dive suspension wheel rate.  Since the lock link locks out the roll suspension, the roll suspension rates have no effect on the amount vehicle sets.

Transient state – Unless the vehicle is going straight at a constant speed, turning at a constant speed or simply standing still, it is in a transient state.  All conventional suspension systems use dampers to help control their response to these transient states.

Sacli suspension has separate dampers for each sub-suspension.  The dampers for the roll suspension allow for low speed movement that the roll suspension is subject to during roll due to cornering loads.  This means the roll suspension dampers have progressive damping curves with soft low speed and stiff high speed reactions.  These dampers allow the roll suspension resist motion during wheel bumps due to road irregularities.  This helps roll suspension passively distinguish between road bumps, suspension roll due to these bumps and suspension roll due to cornering and respond accordingly.

Simulation Video - Bump

Get the Flash Player to see this video.


The dampers for the dive suspension allow for high speed movement as well as low speed movement.  The dive suspension dampers would be set up much like a conventional car damper since they control the entire dive, bump and roll responses.  These dampers would be digressive, providing stiffer low speed damping and softer high speed damping.

Overall, with the added control of the spring rates and selective damping the Sacli suspension can have the wheels of a vehicle lean into the turn with its extreme camber recovery and without suffering the negative effects of extreme camber change during bumps as well as dive, set, jounce and etc.