A work vehicle includes a drive unit, a fan motor, a fan configured to be driven by the fan motor, an overrun state detecting unit configured to detect an overrun state of the drive unit, and a control unit. The control unit is configured to control a rotational speed of the fan to reach a first fan rotational speed by increasing the rotational speed of the fan when a detection value detected by the overrun state detecting unit becomes greater than or equal to a first threshold. The control unit is configured to control the rotational speed of the fan to reach a second fan rotational speed higher than the first fan rotational speed when the detection value becomes greater than or equal to a second threshold greater than the first threshold.

A fluid system for a machine that includes a linkage. The fluid system includes an actuator, an accumulator, a pilot circuit, and a pressure reducing valve. The actuator is configured to manipulate the linkage. The accumulator is configured to store a fluid discharged by the actuator under pressure. The pilot circuit is fluidly coupled to the accumulator and is configured to receive the fluid from the accumulator. Further, the pressure reducing valve is positioned between the accumulator and the pilot circuit to regulate the pressure of the fluid delivered to the pilot circuit from the accumulator.

Two cooling fans acting on different heat exchangers may be driven via parallel circuits from a variable displacement hydraulic pump. At least one of the circuits includes a two position valve operable by a control system to vary the flow resistance of the circuit to share the flow between the two fan motors responsive to the relative heat load on the heat exchangers. The pump displacement is controlled to provide a constant hydraulic output pressure irrespective of the operational state of the or each valve assembly.

A control system that uses an algorithm to control the fan speed in a cooling system for an engine is disclosed. The algorithm is adapted to maintain a cooling medium at a set temperature instead of an operating temperature range of the cooling medium. The algorithm is also adapted to maintain a cooling medium at a set temperature and to build a cooling safety margin in response to an engine output torque percentage that is below an output torque percentage setpoint.

A hydraulic operating device for a cooling fan of a utility vehicle includes a hydraulic motor and a fan assembly, which can be driven by the hydraulic motor for generating a cooling air stream. A hydraulic supply is adjustable in terms of its delivery volume in accordance with pressure feedback for providing pressurized hydraulic liquid. A control valve for setting, in a manner dependent on a control signal that represents a cooling demand, a volume flow that passes through the hydraulic motor, with a sensor line that is branched off in a supply line between the control valve and the hydraulic motor leading to a pressure control inlet of the hydraulic supply.

A cooling system is provided for an engine. The cooling system may have an air cooler configured to cool intake air being supplied to the engine. The cooling system may also have a sensor configured to generate a temperature signal indicative of a temperature of the intake air and a fan in proximity to the air cooler. The cooling system may further have a controller in communication with the sensor and the fan. The controller may be configured to cause the fan to operate at a speed that is a function of the temperature signal when the temperature of the intake air is above a threshold temperature. The controller may further be configured to selectively cause the fan to pulse when the temperature of the intake air drops below the threshold temperature.

The present disclosure provides a method for controlling a cooling fan-brake of construction equipment, including: generating a brake charging signal of a brake unit; charging hydraulic oil with a high flow rate in the brake unit and completing the charging of hydraulic oil; turning a loading valve of a cooling fan unit off and turning an unloading valve of the cooling fan unit on when the hydraulic oil is charged; and turning the loading valve of the cooling fan unit on and turning the unloading valve of the cooling fan unit off after the charging of hydraulic oil is completed and a predetermined time elapses.

An outdoor unit has a frame that carries a ground grooming or working implement, a traction drive, and a cooling fan, all of which comprises loads on a prime mover. A power management controller automatically reduces an operational speed of the traction drive when prime mover droop is present. The cooling fan cools two cooling fluids. The controller stores data representing variable fan speeds for cooling each cooling fluid in both normal and above normal temperature ranges and for use when prime mover droop is present. The controller uses the highest fan speed required for cooling the cooling fluids in the normal range unless the droop fan speed is lower in which case the lower droop fan speed is used but only to the extent that the lower droop fan speed is not lower than the highest fan speed required for cooling the cooling fluids in the above normal temperature range.

A cooling-fan control device for a vehicle that increases the cooling capacity of a cooling oil that cools a brake rapidly and inhibits a brake damage in a case where the brake is applied during traveling or, in addition to the above-described problem-to-be-resolved, suppresses engine horsepower consumption and avoids consumption increase, while increasing the cooling capacity of the brake cooling oil. The rotation speed of the cooling fan is controlled to obtain the higher target rotation speed of a first target rotation speed corresponding to a detected cooling oil temperature and a second target rotation speed corresponding to a detected brake operation amount. The present invention is applicable to a vehicle in which an engine power is distributed to a travel power train and a hydraulic pump, drive wheels are operated via the travel power train, and the cooling fan is actuated via the hydraulic pump.

A cooling system is provided for an engine. The cooling system may have an air cooler configured to cool intake air being supplied to the engine. The cooling system may also have a sensor configured to generate a temperature signal indicative of a temperature of the intake air and a fan in proximity to the air cooler. The cooling system may further have a controller in communication with the sensor and the fan. The controller may be configured to cause the fan to operate at a speed that is a function of the temperature signal when the temperature of the intake air is above a threshold temperature. The controller may further be configured to selectively cause the fan to pulse when the temperature of the intake air drops below the threshold temperature.