A fan drive assembly for a vehicle, which can provide reverse fan flow. The assembly has a fan, where separate forward and reverse clutches are coupled to the fan. The reverse clutch has a greater torque capacity than the forward clutch, such that when the reverse clutch is applied, the forward clutch is made to slip, allowing for the reverse rotation and flow of the fan.

A system for controlling a fan of a vehicle engine. The system comprises: i) a fan configured to selectively cool the vehicle engine; and ii) an engine control module configured to: a) turn on the fan when the engine temperature exceeds a selected temperature threshold; b) determine when the vehicle engine is operating in an engine braking mode; and c) in response to the engine operating in the engine braking mode, turn on the fan when the engine temperature is below the selected temperature threshold. The engine control module turns the fan off as a means of hardware protection of the fan clutch even during engine braking modes.

An axial flow fan for use with a vehicle cooling system includes a hub defining an axis of rotation, and at least five blades supported on the hub. Each blade includes a leading edge, a trailing edge opposite the leading edge, a pressure side extending between the leading edge and the trailing edge, a suction side opposite the pressure side, a tip, and a root opposite the tip along a blade length. A solidity of the axial flow fan, measured as a percentage of an annular flow area between an outer diameter of the hub and an outer diameter of the tips of the blades projected onto a plane perpendicular to the axis of rotation that is occupied by the blades, is less than 40%.

A system for controlling a fan of a vehicle engine. The system comprises: i) a fan configured to selectively cool the vehicle engine; and ii) an engine control module configured to: a) turn on the fan when the engine temperature exceeds a selected temperature threshold; b) determine when the vehicle engine is operating in an engine braking mode; and c) in response to the engine operating in the engine braking mode, turn on the fan when the engine temperature is below the selected temperature threshold. The engine control module turns the fan off as a means of hardware protection of the fan clutch even during engine braking modes.

A cooling fan device includes an electronic control unit that controls an engagement rate of a fan clutch. The electronic control unit executes a first calculation process that calculates an air conditioner requested engagement rate, a second calculation process that calculates, as a first guard value, a value of an engagement rate at which a fan rotation speed increases at a specified speed and an upper limit guarding process that sets a value of the air conditioner requested engagement rate to the first guard value when a calculated value of the air conditioner requested engagement rate in the first calculation process exceeds the first guard value. The electronic control unit further controls the engagement rate of the fan clutch based on a value of the air conditioner requested engagement rate after execution of the upper limit guarding process.

An axial flow fan for use with a vehicle cooling system includes a hub defining an axis of rotation, and at least five blades supported on the hub. Each blade includes a leading edge, a trailing edge opposite the leading edge, a pressure side extending between the leading edge and the trailing edge, a suction side opposite the pressure side, a tip, and a root opposite the tip along a blade length. A solidity of the axial flow fan, measured as a percentage of an annular flow area between an outer diameter of the hub and an outer diameter of the tips of the blades projected onto a plane perpendicular to the axis of rotation that is occupied by the blades, is less than 40%.

An external control type fan clutch device has an electromagnet fixed to a rotating shaft. The electromagnet is energized to activate a valve member formed of a plate spring and an armature and provided to a drive disk or a sealed housing to externally control opening and closing an oil circulating flow passage (oil supply port). The valve member is structured so that the armature attached to the plate spring of the valve member is divided into a plurality of pieces in the direction from the base end side to the oscillating end side of the plate spring to provide a plurality of bend points of the plate spring.

A system and method for dissipating vehicle under hood heat accumulated during stationary engine operation at high load or RPM and/or under high temperature ambient conditions is installed in a vehicle having an engine positioned within an engine compartment, and a cooling fan selectively driven by way of a fan clutch. The system includes a controller connected to the engine and to the fan clutch. The controller determines whether the period of stationary engine operation occurs at or above a threshold engine load or RPM, at or above a threshold engine operating temperature, at or above a threshold ambient temperature, and/or for or longer than a threshold stationary engine operation duration. If so, the at least one controller increases a low idle set point of the engine and commands the fan clutch to engage or remain engaged for a cool-down period following the period of stationary engine operation.

A system and method for dissipating vehicle under hood heat accumulated during stationary engine operation at high load or RPM and/or under high temperature ambient conditions is installed in a vehicle having an engine positioned within an engine compartment, and a cooling fan selectively driven by way of a fan clutch. The system includes a controller connected to the engine and to the fan clutch. The controller determines whether the period of stationary engine operation occurs at or above a threshold engine load or RPM, at or above a threshold engine operating temperature, at or above a threshold ambient temperature, and/or for or longer than a threshold stationary engine operation duration. If so, the at least one controller increases a low idle set point of the engine and commands the fan clutch to engage or remain engaged for a cool-down period following the period of stationary engine operation.

An external control type fan clutch device has an electromagnet fixed to a rotating shaft. The electromagnet is energized to activate a valve member formed of a plate spring and an armature and provided to a drive disk or a sealed housing to externally control opening and closing an oil circulating flow passage (oil supply port). The valve member is structured so that the armature attached to the plate spring of the valve member is divided into a plurality of pieces in the direction from the base end side to the oscillating end side of the plate spring to provide a plurality of bend points of the plate spring.