A hydraulic system includes a hydraulic pump, an output fluid tube connected to the hydraulic pump, an operation fluid tube connected to a hydraulic device, an unload valve connected to the output fluid tube, and having: a supply position in which the operation fluid in the output fluid tube is supplied to the operation fluid tube; and a restrain position in which supply of the operation fluid to the operation fluid tube is restrained, an operation valve connected to the output fluid tube, a control fluid tube connecting the operation valve and the hydraulic device, a warmup fluid tube connecting the control fluid tube and the operation fluid tube, and a check valve provided in the warm-up fluid tube and being for allowing the operation fluid to flow from the control fluid tube side toward the operation fluid tube, and for blocking the operation fluid from flowing side from the operation fluid tube toward the control fluid tube.

A hydraulic system includes a hydraulic pump, an output fluid tube connected to the hydraulic pump, an operation fluid tube connected to a hydraulic device, an unload valve connected to the output fluid tube, and having: a supply position in which the operation fluid in the output fluid tube is supplied to the operation fluid tube; and a restrain position in which supply of the operation fluid to the operation fluid tube is restrained, an operation valve connected to the output fluid tube, a control fluid tube connecting the operation valve and the hydraulic device, a warmup fluid tube connecting the control fluid tube and the operation fluid tube, and a check valve provided in the warm-up fluid tube and being for allowing the operation fluid to flow from the control fluid tube side toward the operation fluid tube, and for blocking the operation fluid from flowing side from the operation fluid tube toward the control fluid tube.

A vehicle includes a chassis, a controllable vehicle component, a hydraulic circuit, a heater, a temperature sensor, and a controller. The hydraulic circuit includes a reservoir configured to store hydraulic fluid, a pump positioned to drive the hydraulic fluid from the reservoir and throughout the hydraulic circuit, and an actuator positioned to selectively receive the hydraulic fluid from the pump to selectively operate the controllable vehicle component. The heater is positioned to facilitate selectively heating the hydraulic fluid. The temperature sensor is positioned to acquire temperature data indicative of a temperature of the hydraulic fluid. The controller is configured to monitor the temperature of the hydraulic fluid and selectively activate at least one of the heater or the pump to thermally regulate the hydraulic fluid (i) to maintain the hydraulic fluid within a target temperature range and (ii) independent of (a) an operator input and (b) engagement of the actuator.

A vehicle includes a chassis, a controllable vehicle component, a hydraulic circuit, a heater, a temperature sensor, and a controller. The hydraulic circuit includes a reservoir configured to store hydraulic fluid, a pump positioned to drive the hydraulic fluid from the reservoir and throughout the hydraulic circuit, and an actuator positioned to selectively receive the hydraulic fluid from the pump to selectively operate the controllable vehicle component. The heater is positioned to facilitate selectively heating the hydraulic fluid. The temperature sensor is positioned to acquire temperature data indicative of a temperature of the hydraulic fluid. The controller is configured to monitor the temperature of the hydraulic fluid and selectively activate at least one of the heater or the pump to thermally regulate the hydraulic fluid (i) to maintain the hydraulic fluid within a target temperature range and (ii) independent of (a) an operator input and (b) engagement of the actuator.

A fluid heating device includes a pressurizing chamber configured to store a working fluid and a heat accumulator disposed in the pressurizing chamber. The heat accumulator includes a heat accumulating member configured to release heat by receiving a pressure applied to the working fluid. The fluid heating device has improved actuation efficiency.

In accordance with an example embodiment, a hydraulic system may include a pump, reservoir, accumulator, hydraulic cylinder, ride control valve assembly, and controller. The ride control valve assembly may include a charging valve, discharging valve, and a head ride control valve. The controller may open the head ride control valve when a ride control feature has been activated, or open the charging valve if the ride control feature has not been activated and a hydraulic fluid warmup is to be performed.

In accordance with an example embodiment, a hydraulic system may include a pump, reservoir, accumulator, hydraulic cylinder, ride control valve assembly, and controller. The ride control valve assembly may include a charging valve, discharging valve, and a head ride control valve. The controller may open the head ride control valve when a ride control feature has been activated, or open the charging valve if the ride control feature has not been activated and a hydraulic fluid warmup is to be performed.

A hydraulic system includes a first output fluid tube connecting between a hydraulic pump to output operation fluid and a first operation valve to change a first pilot pressure of the operation fluid, a second output fluid tube connected between the hydraulic pump and a second operation valve to change a second pilot pressure of the operation fluid, a switching valve provided in the second output fluid tube, and a warm-up fluid tube connected between the first operation valve and the switching valve, wherein the switching valve is switched between a first position allowing the operation fluid to be drained through the first output fluid tube, the first operation valve, the warm-up fluid tube and the switching valve, and a second position allowing the operation fluid to be supplied through second output fluid tube to the second operation valve.

A hydraulic system includes a first output fluid tube connecting between a hydraulic pump to output operation fluid and a first operation valve to change a first pilot pressure of the operation fluid, a second output fluid tube connected between the hydraulic pump and a second operation valve to change a second pilot pressure of the operation fluid, a switching valve provided in the second output fluid tube, and a warm-up fluid tube connected between the first operation valve and the switching valve, wherein the switching valve is switched between a first position allowing the operation fluid to be drained through the first output fluid tube, the first operation valve, the warm-up fluid tube and the switching valve, and a second position allowing the operation fluid to be supplied through second output fluid tube to the second operation valve.

A hydraulic propulsion system converts heat or thermal energy into hydraulic energy, and such hydraulic energy into mechanical work. The hydraulic propulsion system includes a thermal unit, a hydraulic cylinder with pistons and springs mounted therein, one or more hydraulic motors, one or more hydraulic accumulators, and one or more electrical energy generators, as well as a plurality of flow control valves to control the flow of hydraulic fluid between the various components. The hydraulic propulsion system may be enhanced by an energy transmission unit including a wave generator.