Working on the front suspension system forced some decisions on the design. Variable ride height with soft spring value at the high ride height and stiffer spring value at the lower ride height was add to the design spec. Air bags are the easy option but do not meet our spec, in fact they do the opposite as the spring value increases with ride height. The only way to increase ride height is to increase air pressure hence increase spring rate.
The only method possible is a mechanical system which changes the coil spring angle and the effective length. The design in the picture shown my first attempt using a swinging arm to mount the fix chassis end of the coil-overs to.
All the suspension mounting points are taken from the suspension analysis software and transferred to the Cad system. As Delcam Power-shape does not do dynamic modelling, which can show the suspension movement, I am looking at other options to do this. Solid Works, another Cad system does this, so I’ll probably get this checked out by a colleague who has this software.
The pictures above show the coil-over position in the max and min ride heights. The angle of the coil-over in the max ride height position is higher thus reducing the spring rate, also the coil-over length is reduced so the suspension should raise. Much further work is required to test this out before completing the design and adding all the brackets to mount everything.
A coupe of views of the front suspension system so far. Still needs a few load calculations to check that the suspension will raise and lower with the changing coil-over angle and lengths shown.