Suspension system

A vehicle suspension system for use with a vehicle configured to be operated by an operator, the vehicle comprising a sprung portion, a first wheel and a third wheel on a first side of the sprung portion, and a second wheel and a fourth wheel on a second side of the sprung portion, the suspension system comprising:

• a first hydraulic cylinder coupled between the first wheel and the sprung portion, the first hydraulic cylinder having an upper chamber and a lower chamber, each of the upper chamber and the lower chamber having a volume configured to change as the first wheel and sprung portion move relative to one another;
• a second hydraulic cylinder coupled between the second wheel and the sprung portion, the second hydraulic cylinder having an upper chamber and a lower chamber, each of the upper chamber and the lower chamber having a volume configured to change as the second wheel and sprung portion move relative to one another;
• a fluid circuit hydraulically coupled to the first hydraulic cylinder and the second hydraulic cylinder and including a valve movable between a first position and a second position, wherein when the valve is in the first position the upper chamber of the first hydraulic cylinder is hydraulically coupled to the lower chamber of the second hydraulic cylinder and the lower chamber of the first hydraulic cylinder is hydraulically coupled to the upper chamber of the second cylinder, and wherein when the valve is in the second position the upper chamber of the first hydraulic cylinder is hydraulically coupled to the lower chamber of the first hydraulic cylinder and the upper chamber of the second hydraulic cylinder is hydraulically coupled to the lower chamber of the second hydraulic cylinder;
• and
• wherein the valve is coupled to a switch in a central tire inflation system, the switch being movable between a first setting representative of a highway operation mode and a second setting representative of a non-highway operation mode, and
• a control unit operable to monitor the position of the switch and to move the valve to the first position when the central tire inflation system is in the highway operation mode, and to move the valve to the second position when the central tire inflation system is in the non-highway operation mode.

A method of coupling a suspension system to a vehicle having a sprung portion, a first wheel on a first side of the sprung portion, a first hydraulic cylinder coupled between the first wheel and the sprung portion, a second wheel on a second side of the sprung portion opposite the first side, a second hydraulic cylinder coupled between the second wheel and the sprung portion, and a central tire inflation system, the method comprising the steps of:

• configuring the first hydraulic cylinder and the second hydraulic cylinder to move between a first state in which the first hydraulic cylinder and the second hydraulic cylinder are coupled to one another and a second state in which the first hydraulic cylinder and the second hydraulic cylinder are not coupled to one another;
• coupling the first hydraulic cylinder to the second hydraulic cylinder so that when the first hydraulic cylinder and the second hydraulic cylinder are in the first state, the first hydraulic cylinder applies fluid pressure to the second hydraulic cylinder that acts to resist the movement of the second hydraulic cylinder in a first direction and the second hydraulic cylinder applies fluid pressure to the first hydraulic cylinder that acts to resist the movement of the first hydraulic cylinder in a second direction opposite the first direction;
• providing a switch movable between a first position to operate the central tire inflation system in a first configuration representative of highway operation and a second configuration representative of non-highway operation;
• and
• providing a control unit operable to monitor the position of the switch and to move the first hydraulic cylinder and the second hydraulic cylinder between the first state and the second state in response to movement of the central tire inflation system between the first configuration and the second configuration.