Abstract: This invention is directed to a fan assembly for use with temperature exchange units and heat exchange units such as a radiator, a heater, an oil cooler, etc. Most automotive vehicles are powered by an internal combustion engine having water, oil and other fluids to be cooled. And, most of the internal combustion engines are associated with a radiator or a heat exchanger unit for cooling fluid in the engine, transmission or other oils and hydraulic fluids. An automotive vehicle operating at a low speed usually requires a fan to assist the radiator or heat exchanger unit in cooling the cooling fluids. However, at higher ram air speed a fan is not normally required to assist the radiator or heat exchanger in cooling the cooling fluids as there is sufficient cooling due to the natural passage of air over the cooling surfaces of the heat exchange units.

Abstract: A viscous fluid coupling employing an electro magnet which receives electrical pulses in response to a signal received from a heat sensing device to operate a valve arm to seal and unseal an inlet passage fluidly communicating an operating chamber with a storage chamber. The operating chamber is defined by a clutch member and a housing member that are rotatably disposed relative to one another. The storage chamber is defined by the housing and is in fluid communication with the operating chamber via a discharge passage and the inlet passage. A pump displaces fluid from the operating chamber through the discharge passage into the storage chamber. The inlet passage directs fluid when unsealed from the storage chamber to the operating chamber. The valve arm is moved in one direction in response to inducing a magnetic field and in the other direction by a spring when the magnetic field is not induced.

Abstract: A hydraulic motor drives the cooling fan of an internal combustion engine. Fluid flow from a fixed displacement pump is directed through a pilot-operated pressure-compensated control valve to the hydraulic motor. The valve has a continuous bias to a fan-on position for directing fluid to the fan motor. Flow to the fan motor is diverted by the valve as a function of the pressure of the fluid in the system. In addition, flow to the fan motor is diverted as a function of a pilot pressure signal which is controlled by the temperature of the engine coolant fluid. The valve failsafes to a condition directing maximum flow to the fan motor in the event of loss of pilot fluid pressure.

Abstract: A method and apparatus for hydraulically driving and controlling a cooling fan.The apparatus includes a variable displacement hydraulic pump driven by a prime mover and a hydraulic motor connected to the pump and being driven thereby. The motor in turn is connected to a fan which serves to cool fluid passing through an associated heat exchanger. A temperature/force transducer monitors the temperature of fluid flowing from the exchanger and serves to control a pilot relief valve associated therewith. A pressure regulator is connected to the pump and acts in cooperation with the relief valve to control fluid pressure from the pump and thus torque of the motor and speed of the cooling fan.The method includes the steps of pumping hydraulic working fluid to a motor and driving the motor with the full hydraulic output of the pump to power a fan associated with a cooling system heat exchanger.

Abstract: The invention provides a pneumatic control system for a pneumatically operated clutch in the drive to a cooling fan of a vehicle engine. There are two thermostat valves arranged in series in the pneumatic control line. One valve is positioned in the supercharged air passage and the other valve is in the liquid coolant passage. If the temperature at either valve becomes excessive the supply line 22 is connected to relief and the fan clutch automatically engages.

Abstract: Fluid flow regulating systems involving systems for controlling the motor speed of fluid pumping devices are disclosed. The speed control systems involve use of a velocity head force sensor that movably responds to the velocity head forces of an air stream delivered by the pumping device, and these movements in the positions assumed by the force sensor are detected and used to control the power delivered to the motor. Temperature change detectors are used in most embodiments to modify the force sensor movements so as to introduce temperature change factors as well as velocity head force change factors into the control of the power circuitry. Force sensor of the pivotal vane, bendable vane and airfoil types are shown, and temperature sensors of the bimetallic and expandable fluid types are also used.

Abstract: An electronic speed control system for controlling the drive speed of a cooling fan for a motor vehicle. The system includes a temperature sensor to monitor the temperature of the motor coolant to be cooled by the fan. The sensor develops a signal which is proportional to the temperature of the coolant which signal is amplified and modified by an electronic control unit to provide a speed control signal. A rotatable drive unit is coupled to the vehicle drive motor and rotates at a speed which is proportional to the vehicle drive motor's speed. A variable coupler is connected between the drive unit and the cooling fan and is controlled by the speed control signal in order to regulate the speed of the fan and thereby control the temperature of the coolant. The electronic control unit includes means for monitoring the speed of the fan and for limiting the maximum speed of the fan.

Abstract: A variable speed fan drive mechanism for an engine coolant system control by temperature and fan speed signals. The mechanism includes a hydrostatic pump-motor unit (hydrostatic transmission) powered by the engine, for transmitting power to the fan. Mechanical signals related to coolant temperature and fan speed are supplied to a comparator mechanism that delivers a mechanical output control signal. The output control signal is magnified and applied as a control force to vary the displacement of the pump in the hydrostatic unit. The comparator mechanism has the effect of negating engine speed as a control force. Thus, high engine speeds (that would tend to produce unduly large hydraulic flows through the pump-motor circuit) are reflected in high fan speed signals fed into the comparator mechanism, which produces a "corrected" output signal that appropriately reduces pump dislacement to thus reduce the fan speed to low energy consumption levels.

Abstract: A constant current source is provided for the energizing circuit of an electromotor driving a blower. The constant current source includes a battery connected in parallel with a series circuit including the energizing circuit of the motor, the emitter-collector circuit of a transistor and a control resistance. The transistor and control resistance are part of the constant current source. The base of the transistor is connected to the output of a differential amplifier the first input of which receives a reference voltage while the second input receives a voltage corresponding to the voltage across the control resistance and thus the energizing current. The reference voltage is derived from a potentiometer connected in parallel with the battery.

Abstract: A variable speed drive system for driving one or, preferably, a plurality of fans at a desired, controllable speed. The fans are rotated by motors in fluid communication with variable displacement pumps. The motors rotate the fans at a speed corresponding to the fluid displacement of the pumps and an adjusting structure operably connected to the pumps regulates the fluid displacement of the pumps so that the fans are driven by the motors at a desired speed. Preferably, the adjusting structure includes a temperature sensor and a pump displacement control responsive to the temperature sensor so that the fluid displacement of the pumps is automatically regulated in response to the temperature of the substance cooled by the fans.