The purpose of the present invention is to provide a cooling fan control device for a construction machine, whereby the effects of heat caused by warm-up operation can be suppressed. This cooling fan control device is equipped with a control unit (10a) that controls the rotational speed of a cooling fan (21) in accordance with a main pump discharge pressure (P) detected by a main pump discharge pressure sensor (25), an engine cooling water temperature (Tw) detected by an engine cooling water temperature sensor (26), a hydraulic oil temperature (To) detected by a hydraulic oil temperature sensor (27), and an engine rotational speed (E) detected by an engine rotational speed sensor (28). The cooling fan (21) is rotated at the rotational speed controlled by the control unit (10a), thereby sending the generated cooling air to an oil cooler (19) and a control valve (13).

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.

Agricultural machines such as sprayers can be improved by providing a control system configured to adjust an engine cooling package fan with variable speeds, to thereby minimize parasitic losses, based on progress of the HVAC system for attaining a desired temperature in the operator cab. In one aspect, as a gap between actual and desired temperatures (temperature differential) in the cab minimizes, the cooling package fan can be variably adjusted to increase or decrease in speed, depending on heating or cooling occurring in the cab, respectively. However, if a temperature of an area in the engine compartment reaches a predetermined threshold, such variable speed control can cease, and the cooling package fan can instead be controlled to cool the area.

To reduce increase of the temperature of a control device of a supercharger and increase the lifetime of the control device of the supercharger, a work machine includes a variable geometry supercharger having changeable supercharge pressure and a working device. The work machine includes a variable displacement work hydraulic pump configured to be driven by an engine and supply pressure oil to an actuator configured to drive the working device; a supercharger control device configured to control the supercharger; a temperature detection device configured to detect the temperature of the supercharger control device; and a main control device configured to restrict, in case the temperature of the supercharger control device is higher than a first temperature, a maximum absorbing torque of the work hydraulic pump as compared to case the temperature of the supercharger control device is lower than the first temperature.

To curb temperature rises in a control device for a supercharger and extend the life of the control device for the supercharger, a work vehicle includes a variable geometry supercharger with variable boost pressure, and a working device driven by pressure oil discharged from a working hydraulic pump, the work vehicle further including: a supercharger control device adapted to control the supercharger; a temperature detection device adapted to detect temperature of the supercharger control device; and a main control device adapted to limit at least one of maximum rotational speed of an engine and maximum vehicle speed of the work vehicle in case the temperature of the supercharger control device is above a predetermined temperature as compared to case the temperature of the supercharger control device is below the predetermined temperature.

A driving arrangement for a snow blower device that includes a power source and an impeller, comprises a main body and a drive train within and about the main body. The drive train comprises a right angle gear box in driving engagement with both the power source and the impeller of the snow blower device for transferring torque from the power source to the impeller, thereby driving the impeller of the snow blower device. A cooling system for cooling a main power source configured to drive a snow blower of the snow blower device, comprises an auxiliary power source operatively coupled to the main power source and a fan operatively coupled to the auxiliary power source for cooling the main power source.

A hydraulic driven fan system includes at least one first fan motor and a second fan motor connected in series with each other. The system also includes a fixed displacement pump configured to supply a pressurized flow of a hydraulic fluid to the at least one first and second fan motors. The system includes a proportional flow control valve in fluid communication with the at least one first fan motor and configured to allow a regulated amount of the pressurized flow of the hydraulic fluid there through to the corresponding at least one first fan motor. The system includes a pressure compensator disposed parallel to the proportional flow control valve and configured to maintain a pressure difference across the proportional flow control valve. The system further includes a proportional pressure relief valve disposed parallel to the second fan motor and configured to control a pressure difference across the second fan motor.

A fan control system includes a tank, a pump, a hydraulic motor, a fan, and a control valve. The control valve is adapted to selectively direct a flow of hydraulic fluid from the pump through the control valve into a pressure control chamber of the hydraulic motor or from the pressure control chamber to the tank to vary the control pressure therein to move the hydraulic motor's swashplate between forward and reverse positions. The control valve is adapted to selectively direct hydraulic fluid from the pump into the pressure control chamber such that the control pressure therein is pressurized to an idle pressure to move the swashplate to an intermediate position between the forward and reverse positions such that the output shaft rotates at an idle rate which is less than the rotational speed of the output shaft when in the forward mode.

Valve device. 2. Valve device for controlling a fluid flow, consisting of a flow control valve (15), which comprises a valve housing (19) with at least one supply connection (9) and one user connection (11) as well as a valve piston (17) that is guided inside the valve housing (19) longitudinally moveable and which controls the passage to the user connection (11) by means of a thermocouple (61) via an orifice (37, 39) depending on the temperature of the fluid flow, and a pressure compensator (21), connected to the supply connection (9), keeps the respective pressure drop across the orifice (37, 39) constant.

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.