Diagnosis device and diagnosis method for fan coupling device

摘要

A fan coupling device 1 connecting an internal combustion engine 31 to a cooling fan 21 comprises an input shaft 3 driven to rotate by the engine 31, a fluid coupling 12 that transmits torque from the input shaft 3 to the cooling fan 21 via a fluid, and a solenoid valve 13 having a valve main body 18 that adjusts a fluid amount in the fluid coupling 12. A determination as to whether or not the valve main body 18 is stuck in a lifted position on the basis of a rotation speed of the cooling fan 21, is started after the elapse of a predetermined time following output of a signal for returning the valve main body 18 to a closed position, The sticking determination can be performed with a high degree of precision without being affected by variation in the rotation speed of the input shaft 3.

主权项

1. A diagnosis device for use with a fan coupling device which connects an internal combustion engine to a cooling fan that blows cooling air onto a radiator for cooling a coolant of the internal combustion engine, the fan coupling device comprising:
an input shaft that is driven to rotate by the internal combustion engine; a fluid coupling that transmits torque from the input shaft to the cooling fan via a fluid; and a solenoid valve that adjusts a fluid amount in the fluid coupling, the solenoid valve comprising a valve main body that is displaced in response to energization between a lifted position in which the fluid amount increases and a closed position in which the fluid amount decreases, wherein the diagnosis device is used to determine whether or not the valve main body is stuck in the lifted position, the diagnosis device comprising: a sensor that detects a rotation speed of the cooling fan; and a controller programmed to:
output a signal in order to return the valve main body to the closed position; andstart to determine whether or not the valve main body is stuck in the lifted position on the basis of the rotation speed of the cooling fan following the elapse of a predetermined time from output of the signal.