Suspension system

Abstract

A vehicle subassembly includes first and second hydraulic cylinders each having an upper chamber and a lower chamber. A fluid circuit is hydraulically connected to the first and second hydraulic cylinders and includes a valve movable between a first position where the upper chamber of the first hydraulic cylinder and the lower chamber of the second hydraulic cylinder are hydraulically connected and the lower chamber of the first hydraulic cylinder and the upper chamber of the second cylinder are hydraulically connected, and a second position where the upper chamber and the lower chamber of the first hydraulic cylinder are hydraulically connected and the upper chamber and lower chamber of the second hydraulic cylinder are hydraulically connected. A control unit is operable to position the valve in at least one of the first position and the second position based on an operating variable of the vehicle.

1 . A subassembly for a vehicle, the subassembly comprising:
 first and second hydraulic cylinders each having an upper chamber and a lower chamber;   a fluid circuit hydraulically connected to the first and second hydraulic cylinders and including a valve movable between a first position where the upper chamber of the first hydraulic cylinder and the lower chamber of the second hydraulic cylinder are hydraulically connected and the lower chamber of the first hydraulic cylinder and the upper chamber of the second cylinder are hydraulically connected, and a second position where the upper chamber and the lower chamber of the first hydraulic cylinder are hydraulically connected and the upper chamber and lower chamber of the second hydraulic cylinder are hydraulically connected;   a control unit operable to position the valve in at least one of the first position and the second position based on an operating variable of the vehicle.   
   
   
       2 . The subassembly of  claim 1 , wherein the operating variable comprises a lateral acceleration, and the control unit is operable to position the flow control device in the first position for a first lateral acceleration and in the second position for a second lateral acceleration, wherein the first lateral acceleration is greater than the second lateral acceleration. 
   
   
       3 . The subassembly of  claim 1 , wherein the operating variable comprises speed, and the control unit is operable to position the flow control device in the first position for a first speed and in the second position for a second speed, wherein the first speed is greater than the second speed. 
   
   
       4 . The subassembly of  claim 1 , wherein the operating variable comprises a load, and the control unit is operable to position the flow control device in the first position for a first load and in the second position for a second load, wherein the first load is greater than the second load. 
   
   
       5 . The subassembly of  claim 1 , wherein the operating variable comprises a turning angle, and the control unit is operable to position the flow control device in the first position for a first turning angle and in the second position for a second turning angle, wherein the first turning angle is greater than the second turning angle. 
   
   
       6 . The subassembly of  claim 1 , wherein the operating variable comprises a pressure within the fluid circuit, and the control unit is operable to position the flow control device in the first position for a first pressure and in the second position for a second pressure, wherein the second pressure is greater than the first pressure. 
   
   
       7 . A subassembly for a vehicle, the subassembly comprising:
 a first hydraulic cylinder having an upper chamber and a lower chamber;   a second hydraulic cylinder having an upper chamber and a lower chamber;   a fluid circuit hydraulically coupled to the first hydraulic cylinder and the second hydraulic cylinder and including a flow control device movable between a first position and a second position, wherein when the flow control device 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 flow control device 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;   a control unit operable to position the flow control device in at least one of the first position and the second position in response to an operating variable of the vehicle.   
   
   
       8 . The subassembly of  claim 7 , wherein the operating variable of the vehicle comprises a lateral acceleration of the vehicle, and the control unit is operable to position the flow control device in the first position in response to a first lateral acceleration and in the second position in response to a second lateral acceleration, wherein the first lateral acceleration is greater than the second lateral acceleration. 
   
   
       9 . The subassembly of  claim 7 , wherein the operating variable of the vehicle comprises a speed of the vehicle, and the control unit is operable to position the flow control device in the first position in response to a first speed and in the second position in response to a second speed, wherein the first lateral speed is greater than the second speed. 
   
   
       10 . The subassembly of  claim 7 , wherein the operating variable of the vehicle comprises a load carried by the vehicle, and the control unit is operable to position the flow control device in the first position in response to a first load and in the second position in response to a second load, wherein the first load is greater than the second load. 
   
   
       11 . The subassembly of  claim 7 , wherein the operating variable of the vehicle comprises a turning angle, and the control unit is operable to position the flow control device in the first position in response to a first turning angle and in the second position in response to a second turning angle, wherein the first turning angle is greater than the second turning angle. 
   
   
       12 . The subassembly of  claim 7 , wherein the operating variable of the vehicle comprises a pressure within the fluid circuit, and the control unit is operable to position the flow control device in the first position in response to a first pressure and in the second position in response to a second pressure, wherein the second pressure is greater than the first pressure. 
   
   
       13 . The subassembly of  claim 7 , wherein the flow control device comprises a valve. 
   
   
       14 . A subassembly for a vehicle comprising:
 first and second hydraulic cylinders each having an upper chamber and a lower chamber;   a fluid circuit hydraulically coupled to the first and second hydraulic cylinders 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;   a central tire inflation system having a first setting representative of a first operation mode and a second setting representative of a second operation mode;   a control unit operable to move the valve to the first position when the central tire inflation system is in the first setting and to move the valve to the second position when the central tire inflation system is in the second setting.   
   
   
       15 . The subassembly for a vehicle of  claim 14 , wherein the first operation mode comprises on-road operation and the second operation mode comprises off-road operation. 
   
   
       16 . The subassembly for a vehicle of  claim 14 , further comprising at least one accumulator hydraulically coupled to the fluid circuit. 
   
   
       17 . The subassembly for a vehicle of  claim 14 , further comprising a first accumulator hydraulically coupled to the fluid circuit between the upper chamber of the first hydraulic cylinder and the lower chamber of the second hydraulic cylinder, and a second accumulator hydraulically coupled to the circuit between the lower chamber of the first hydraulic cylinder and the upper chamber of the second hydraulic cylinder. 
   
   
       18 . The subassembly for a vehicle of  claim 14 , wherein the first and second hydraulic cylinders are hydro-pneumatic springs. 
   
   
       19 . The subassembly for a vehicle of  claim 14 , wherein the vehicle has a first ride height when the fluid circuit has a first volume of fluid and wherein the vehicle has a second ride height different than the first ride height when the fluid circuit has a second volume of fluid different than the first volume of fluid.