US 2023/0417253 A1 · FAN DRIVE SYSTEM

Abstract

The fan system includes a fan operated by a hydraulic motor which is driven by a hydraulic variable displacement pump that includes a displacement volume adjusting element. A tilt angle of the displacement volume adjusting element can be adjusted by controlling a tilt current supplied to an electronic displacement control unit. The hydraulic fan system further includes means for determining the volumetric flow rate of the pump and a control unit having: a signal connection to the means for determining the volumetric flow rate of the pump, a signal connection to a fan speed setting device, and a fan speed calculating unit for calculating a fan speed from the determined volumetric flow rate, a fan speed error determining unit for determining a fan speed error by comparing the calculated fan speed to the fan speed set by the fan speed setting device. The control unit can supply an adapted tilt current to the electronic displacement control unit in order to adjust the tilt angle of the displacement volume adjusting device, such that the volumetric flow rate can be adapted in order to reduce the fan speed error, wherein an ideal tilt current value is derived from the calculated fan speed and safety actions are performed in order to prevent damage to the fan, if the difference between the ideal tilt current value and the adapted tilt current is higher than a tilt current threshold value.

Claims19

Dependent claims

A method for controlling the speed of a hydraulic fan system comprising a fan operated by a hydraulic motor which is driven by a hydraulic variable displacement pump comprising a displacement volume adjusting element whose tilt angle can be adjusted by means of controlling a tilt current supplied to an electronic displacement control unit, the method comprising the following repetitive steps:

a) Determining the volumetric flow rate of the pump by means of measuring operational parameters of the pump;
b) Calculating a fan speed based on the volumetric flow rate determined in step a) using equations representing the physical correlation between the volumetric flow rate and the fan speed;
c) Determining a fan speed error by comparing the calculated fan speed of step b) with a fan speed set value provided by an input device;
d) Adapting the tilt current supplied to the electronic displacement control unit in order to adjust the tilt angle of the displacement volume adjusting element, such that the fan speed error is reduced, wherein the tilt current adaptation is calculated based on a fan speed error using a P-, PI-, PID-, Fuzzy- or a Predictive Controller or a similar type of linear or non-linear controller;
wherein the following steps are executed simultaneously to the steps c) to d):
e) Deriving an ideal tilt current value from the calculated fan speed of step b);
f) Performing safety actions in order to prevent damage to the fan, if the difference between the ideal tilt current value derived in step e) and the adapted tilt current adapted in step d) is higher than a tilt current threshold value.

4 more elements

A hydraulic fan system comprising:

a fan operated by a hydraulic motor;
a hydraulic variable displacement pump for driving the hydraulic motor, comprising a tiltable displacement volume adjusting element whose tilt angle can be adjusted by means of a control unit controlling a tilt current which can be supplied to an electronic displacement control device;
a fan speed setting device for setting a fan speed set value according to an input command;
means for determining the volumetric flow rate of the pump;
wherein the control unit comprises:
a volumetric flow rate signal connection to the means for determining the volumetric flow rate of the pump;
a fan speed set value signal connection to the electronic displacement control device;
a fan speed calculating unit for calculating a fan speed based on the determined volumetric flow rate;
a fan speed error determining unit for determining a fan speed error by comparing the calculated fan speed with the fan speed set value set by the fan speed setting device;
and
wherein the control unit is capable of adapting the tilt current supplied to the electronic displacement control device such that the tilt angle can be adjusted in order to reduce the fan speed error, wherein the tilt current adaptation is calculated based on a fan speed error using a P-, PI-, PID-, Fuzzy- or a Predictive Controller or a similar type of linear or non-linear controller, and wherein the control unit further comprises a fan grill blockage detection unit assigning to each calculated fan speed an ideal tilt current value, comparing the ideal tilt current value to the value of the tilt current adapted by means of the control unit, and performing safety actions for preventing damage to the fan, if the difference between the ideal tilt current value and the adapted tilt current value is higher than a tilt current threshold value.

8 more elements

Dependencies are inferred from the claim text.

Fan drive system

Life of this patent

Fan drive system

Life of this patent

Abstract

Claims19