Electronic control of vehicle air suspension

A vehicle suspension system for a vehicle that lies in the atmosphere and that has a frame with laterally spaced first and second opposite sides, a plurality of axle assemblies including a first axle assembly, a first tilt arm having a first arm end pivotally mounted about a horizontal axis on said frame and having a second arm end connected to a first side of said first axle assembly to move up and down with said first side of said first axle assembly, a first air bag that is supported by said first side of said first axle assembly and that supports said frame, and a source of pressured air, comprising

• first and second tilt sensors that each produces an electrical output indicating the tilt of the corresponding sensor with respect to gravity about substantially parallel tilt axes, said first tilt sensor mounted on said tilt arm and said second tilt sensor mounted on said frame;
• a control coupled to said tilt sensors, said source of pressured air and said air bag, said control constructed to generally flow pressured air from said source of pressured air to said first air bag when the difference in tilt angles indicated by said sensors indicates an air bag height below a predetermined value, and to flow air from said air bag into the atmosphere when the difference in tilt angles indicated by said sensors indicates an air bag height above a predetermined value.

A vehicle that has laterally opposite sides and that has axle assemblies with axles that rotate about lateral axes, said vehicle having a frame, said vehicle having swing arm means lying at each side, each swing arm means having opposite arm ends each pivotally coupled respectively to said frame and to a first of said axles about a primarily laterally-extending axis, and said vehicle having first and second air bags each extending substantially between said frame and one of said axle assemblies, comprising:

• tilt sensor means coupled to a first of said swing arm means for generating signals indicating tilt of said first swing arm;
• control means connected to said tilt sensor means for controlling air pressure in at least said first air bag to generally maintain a predetermined height of said first air bag.