Semi-active ride control for a mobile machine

A ride control system for a work vehicle, the work vehicle having a work tool, at least one hydraulic cylinder, a fluid reservoir, and a fluid pressure source, the hydraulic cylinder having a head end and a rod end, the ride control system comprising:

• a directional control valve;
• a ride control valve having a first ride control valve state and a second ride control valve state, the ride control valve comprising a proportional relief valve and a solenoid valve;
• and
• a controller having a first mode and a second mode, the first mode placing the first ride control valve in the first ride control valve state, the first ride control valve state allowing fluid at the head end to flow toward the fluid reservoir when a fluid at the head end reaches a dynamically set relief pressure, the work tool moving from a first position to a second position as the fluid at the head end flows toward the fluid reservoir, the first ride control valve state allowing the ride control valve to stop the fluid at the head end from flowing toward the reservoir when the fluid at the head end falls below the relief pressure at a first level, the controller adjusting the proportional relief valve to a relief pressure that is higher than the initial preset relief pressure in proportion to the volume of fluid flowing from the head end causing the directional control valve to allow fluid from the fluid pressure source to flow to the head end and move the work tool toward the first position after it has moved to the second position, the second directional control valve state stopping fluid from flowing from the fluid pressure source to the head end, the controller capable of automatically changing a state of the directional control valve.

A work vehicle having a ride control system, a work tool, at least one hydraulic cylinder, a fluid reservoir, and a fluid pressure source, the hydraulic cylinder having a head end and a rod end, the ride control system comprising:

• a directional control valve;
• a ride control valve having a first ride control valve state and a second ride control valve state, the ride control valve comprising a proportional relief valve and a solenoid valve;
• and
• a controller having a first mode and a second mode, the first mode placing the first ride control valve in the first ride control valve state, the first ride control valve state allowing fluid at the head end to flow toward the fluid reservoir when a fluid at the head end reaches a dynamically set relief pressure, the work tool moving from a first position to a second position as the fluid at the head end flows toward the fluid reservoir, the first ride control valve state allowing the ride control valve to stop the fluid at the head end from flowing toward the reservoir when the fluid at the head end falls below the relief pressure at a first level, the controller adjusting the proportional relief valve to a relief pressure that is higher than the initial preset relief pressure in proportion to the volume of fluid flowing from the head end causing the directional control valve to allow fluid from the fluid pressure source to flow to the head end and move the work tool toward the first position after it has moved to the second position, the second directional control valve state stopping fluid from flowing from the fluid pressure source to the head end, the controller capable of automatically changing a state of the directional control valve.

A method of achieving ride control for a work vehicle, the work vehicle including a ride control system, a work tool, a boom, at least one hydraulic cylinder, a fluid reservoir, and a fluid pressure source, the hydraulic cylinder having a head end and a rod end, the ride control system comprising:

• a directional control valve;
• a ride control valve, the ride control valve comprising a proportional relief valve and a solenoid valve;
• and a controller, the method comprising:
• setting the ride control valve to a first relief pressure that allows fluid to flow from the head end at the first relief pressure;
• recording a first boom angle;
• allowing fluid to flow from the head end and, consequently, allowing the boom to move from the first boom angle to a second boom angle, the second boom angle placing the work tool at a lower position than the first boom angle;
• adjusting the ride control valve to a second relief pressure that is sufficient to move the boom from the second boom angle toward the first boom angle;
• opening the direction control valve to allow fluid from the fluid pressure source to flow into the head end at the second relief pressure;
• closing the direction control valve to stop fluid from flowing from the pressure source to the head end when the boom has moved from the second boom angle to a boom angle that is approximately equal to the first boom angle.