Variable Pitch Fan Control System

Abstract

A fan control system for a variable pitch fan of a work vehicle, comprising a first sensor that measures parameters of a cooling system and a blade pitch module that adjusts the pitch of a plurality of blades of the variable pitch fan to generate an air flow in a first direction. A reverse module selectively commands the fan to reverse, including instructing the blade pitch module to temporarily adjust the pitch of the plurality of blades to generate an air flow in a second direction. A first timer module, in response to the reverse module commanding the fan to reverse, resets and increments a first timer and compares the first timer with a first threshold. A first reverse prevention module, in response to the first timer being less than the first threshold, prevents the reverse module from commanding the fan to reverse by indicating that a first type of fan reverse is not allowed.

Description

Technical Field

[0001] The present disclosure relates to the control of a fan in a work vehicle, and more particularly, to the control of a variable pitch fan in a work vehicle. Background Art

[0002] Work machines (such as those in the agricultural, construction, and forestry industries) can include a cooling system for providing an air flow to an engine or other heat generating device of the work machine. A heat exchanger (e.g., an air cooler), a fan, etc. can form part of the cooling system. During work operations, debris and other particulates may enter the cooling system and cause problems with cooling the engine - for example, clogging the air inlets of the heat exchanger or the fan. Cleaning operations are typically required to remove debris from the cooling system. However, this can be difficult because debris can typically reach hard-to-reach areas in the cooling system without removing or moving components (such as the heat exchanger or the fan) to access these areas.

[0003] The background description provided herein is for the purpose of generally presenting the context of the present disclosure. To the extent described in this background art section, the work of the currently named inventors and aspects that may not qualify as prior art at the time of filing are not expressly or implicitly considered prior art against the present disclosure. Summary of the Invention

[0004] A fan control system for a variable pitch fan of a work vehicle includes: a first sensor configured to measure a parameter of a cooling system of the work vehicle; and a blade pitch module configured to receive the measured parameter from the first sensor and adjust the pitch of a plurality of blades of the variable pitch fan based on the measured parameter to generate a first air flow in a first direction. The system further includes a reverse module configured to selectively command the fan to reverse, the fan reverse including instructing the blade pitch module to temporarily adjust the pitch of the plurality of blades of the variable pitch fan to generate a second air flow in a second direction. The second direction is opposite to the first direction. The system further includes a first timer module configured to reset and increment a first timer in response to the reverse module commanding the fan to reverse and compare the first timer with a first threshold. The system further includes a first reverse prevention module configured to prevent the reverse module from commanding the fan to reverse by indicating that a first type of fan reverse is not allowed in response to determining that the first timer is less than the first threshold.

[0005] Among other features, the fan control system includes: a second sensor that monitors the status of a clutch of the work vehicle; and a second timer module configured to (i) receive the status of the clutch from the second sensor, (ii) increment the second timer in response to the clutch status indicating that the clutch is engaged, and (iii) compare the second timer to a second threshold. The reverse module is configured to command the fan to reverse in response to determining (i) that the second timer is equal to or greater than the second threshold and (ii) that the first reverse prevention module does not indicate that a first type of fan reverse is not permitted.

[0006] Among other features, the fan control system includes a second reverse prevention module configured to prevent the reverse module from commanding the fan to reverse by indicating that a second type of fan reverse is not permitted in response to determining that the first timer is less than the first threshold. The reverse module is configured to receive an instruction requesting a second type of fan reverse via an operator interface and to command the fan to reverse in response to (i) receiving the instruction and (ii) determining that the second reverse prevention module does not indicate that a second type of fan reverse is not permitted.

[0007] Among other features, the work vehicle includes an engine. The fan control system further includes: a second sensor configured to measure the speed of the engine; and an engine status module configured to (i) receive the measured engine speed from the second sensor, (ii) compare the measured engine speed to a first speed threshold, and (iii) compare the measured engine speed to a second speed threshold. The first reverse prevention module is configured to indicate that a first type of fan reverse is not permitted in response to determining (i) that the measured engine speed is less than the first speed threshold or (ii) that the measured engine speed is greater than the second speed threshold. The first speed threshold is less than the second speed threshold.

[0008] In an additional feature, the engine status module is configured to compare the measured engine speed to a third speed threshold. The fan control system further includes a second reverse prevention module configured to prevent the reverse module from commanding the fan to reverse by indicating that a second type of fan reverse is not permitted in response to determining (i) that the engine speed is less than the third speed threshold or (ii) that the engine speed is greater than the first speed threshold. The reverse module is configured to receive an instruction requesting a second type of fan reverse via an operator interface and to command the fan to reverse in response to (i) receiving the instruction and (ii) determining that the second reverse prevention module does not indicate that a second type of fan reverse is not permitted. The third speed threshold is less than both the first speed threshold and the second speed threshold.

[0009] Among other features, the fan control system includes a third sensor that measures the ambient temperature associated with the work vehicle. The first anti-reversal module is configured to receive the measured ambient temperature from the third sensor and, in response to determining that the received ambient temperature is less than a temperature threshold, indicate that a first type of fan reversal is not permitted.

[0010] Among other features, the fan control system includes a cooling system module that is configured to set the state of the cooling system based on a fault code associated with one or more components of the cooling system and, in response to receiving at least one fault code, set the state of the cooling system to an error state. The first reversal prevention module is configured to, in response to determining that the cooling system is in an error state, indicate that a first type of fan reversal is not permitted.

[0011] A method for controlling a variable pitch fan of a work vehicle, the method including: measuring a parameter of the cooling system of the work vehicle; performing a first fan reversal, including temporarily adjusting the pitch of a plurality of blades of the variable pitch fan to generate a second air flow in a second direction; and resetting and incrementing a first timer in response to performing the fan reversal. The method further includes comparing the first timer with a first threshold and preventing a second fan reversal in response to determining that the first timer is less than the first threshold.

[0012] Among other features, the method includes: receiving a state of a clutch of the work vehicle from a second sensor; resetting a second timer in response to performing the first fan reversal; and incrementing the second timer in response to a state of the clutch indicating that the clutch is engaged. The method further includes comparing the second timer with a second threshold and performing a second fan reversal in response to determining that the first timer is greater than the first threshold and the second timer is greater than the second threshold.

[0013] Among other features, the method includes performing a second fan reversal in response to (i) receiving a reversal request from an operator of the work vehicle and (ii) determining that the first timer is greater than the first threshold.

[0014] Among other features, the work vehicle includes an engine. The method includes: measuring the speed of the engine; comparing the measured engine speed with a first speed threshold; and comparing the measured engine speed with a second speed threshold. The method further includes performing a second fan reversal in response to determining (i) that the first timer is greater than the first threshold, (ii) that the measured engine speed is greater than the first speed threshold, and (iii) that the measured engine speed is less than the second speed threshold. The first speed threshold is less than the second speed threshold.

[0015] In additional features, the method includes: comparing the measured engine speed to a third speed threshold; and performing a second fan reverse in response to receiving a reverse request from an operator of the work vehicle and determining (i) that a first timer is greater than a first threshold, (ii) that the measured engine speed is greater than the third speed threshold, and (iii) that the measured engine speed is less than a second speed threshold. The third speed threshold is less than both the first speed threshold and the second speed threshold.

[0016] In other features, the method includes: receiving an ambient temperature associated with the work vehicle from a third sensor; comparing the received ambient temperature to a temperature threshold; and performing a second fan reverse in response to determining that the first timer is greater than the first threshold and that the received ambient temperature is greater than the temperature threshold.

[0017] In other features, the method includes determining that the cooling system is in an error state in response to receiving a fault code associated with a component of the cooling system. The method further includes performing a second fan reverse in response to determining (i) that the first timer is greater than the first threshold, (ii) that a second timer is greater than a second threshold, and (iii) that the cooling state is not in an error state.

[0018] A non - transitory computer - readable medium storing processor - executable instructions for controlling a variable pitch fan of a work vehicle, the instructions including: measuring a parameter of a cooling system of the work vehicle; adjusting a pitch of a plurality of blades of the variable pitch fan based on the parameter to generate a first air flow in a first direction; and performing a first fan reverse, including temporarily adjusting the pitch of the plurality of blades of the variable pitch fan to produce a second air flow in a second direction. The instructions further include: resetting and incrementing a first timer in response to performing the fan reverse; comparing the first timer to a first threshold; and preventing a second fan reverse in response to determining that the first timer is less than the first threshold.

[0019] In other features, the instructions include: receiving a state of a clutch of the work vehicle from a second sensor; resetting a second timer in response to performing the first fan reverse; and incrementing the second timer in response to a state of the clutch indicating that the clutch is engaged. The instructions further include comparing the second timer to a second threshold, and performing a second fan reverse in response to determining that the first timer is greater than the first threshold and that the second timer is greater than the second threshold.

[0020] In other features, the instructions include performing a second fan reverse in response to (i) receiving a reverse request from an operator of the work vehicle and (ii) determining that the first timer is greater than the first threshold.

[0021] Among other features, the work vehicle includes an engine. The instructions include: measuring the speed of the engine; comparing the measured engine speed with a first speed threshold; and comparing the measured engine speed with a second speed threshold. The instructions also include performing a second fan reverse in response to determining (i) that a first timer is greater than a first threshold, (ii) that the measured engine speed is greater than the first speed threshold, and (iii) that the measured engine speed is less than the second speed threshold. The first speed threshold is less than the second speed threshold.

[0022] In yet additional features, the instructions include: comparing the measured engine speed with a third speed threshold; and performing a second fan reverse in response to receiving a reverse request from an operator of the work vehicle and determining (i) that a first timer is greater than a first threshold, (ii) that the measured engine speed is greater than the third speed threshold, and (iii) that the measured engine speed is less than the second speed threshold. The third speed threshold is less than both the first speed threshold and the second speed threshold.

[0023] Among other features, the instructions include determining that the cooling system is in an error state in response to receiving a fault code associated with a component of the cooling system. The instructions also include performing a second fan reverse in response to determining (i) that a first timer is greater than a first threshold, (ii) that a second timer is greater than a second threshold, and (iii) that the cooling state is not in an error state.

[0024] Additional application areas of the present disclosure will become apparent from the detailed description, the claims, and the drawings. The detailed description and the specific examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present disclosure will be more fully understood from the detailed description and the drawings.

[0026] Figure 1 is a perspective view of an example work vehicle including a fan control system in accordance with the principles of the present invention.

[0027] Figure 2 is a side view of an example work vehicle including a fan control system in accordance with the principles of the present invention.

[0028] Figure 3 is a partial view of an example variable pitch fan.

[0029] Figure 4 is a functional block diagram of an example implementation of a fan control system in accordance with the principles of the present disclosure.

[0030] Figures 5A to 5C is a flowchart of an example operation performed by an implementation of the fan control system.

[0031] In the drawings, reference numerals may be reused to identify similar and / or identical elements. DETAILED DESCRIPTION

[0032] Figure 1 and Figure 2 An example work vehicle 10 is shown. The work vehicle 10 shown is a cotton harvester 15, such as a cotton picker or a cotton stripper. Although the work vehicle 10 is depicted as a cotton stripper and a cotton picker, the present disclosure also contemplates other types of work vehicles, such as combine harvesters, tractors, self-propelled sprayers, and other types of off-road work machines.

[0033] The work vehicle 10 includes a chassis 20. The chassis 20 shown is supported by a front ground-engaging member 25 and a rear ground-engaging member 30. Although the front ground-engaging member 25 and the rear ground-engaging member 30 of the work vehicle 10 are depicted as wheels, other supports, such as tracks, may also be contemplated. The work vehicle 10 is adapted to move through a field 35 to perform tasks, such as harvesting crops. By way of example only, the work vehicle 10 may be configured to harvest cotton, corn, soybeans, rapeseed, straw, hay, alfalfa, or other crops. An operator station 40 is supported by the chassis 20.

[0034] An operator interface 45 is positioned in the operator station 40. In some embodiments, the operator interface 45 includes a display screen - for example, a liquid crystal display (LCD), a light-emitting diode (LED) screen, an organic LED (OLED) screen, or a CRT monitor. The display screen of the operator interface 45 may present various features and / or parameters of the work vehicle 10 through a graphical user interface (GUI). In various embodiments, the operator interface 45 may include one or more user input devices - for example, buttons, switches, touchscreens, and / or levers. An operator of the work vehicle 10 may adjust various operating parameters of the work vehicle 10 through the operator interface 45 - for example, by actuating one or more of the user input devices.

[0035] Referring Figure 2 , a power module 50 may be supported below the chassis 20. The power module may be an engine 55 that drives a hydraulic motor 60 or a mechanical drive 65 to power a variable pitch fan 70. An operator may set a minimum power of the power module 50 from the operator interface 45. The operator may also set a minimum engine speed from the operator interface 45. A water, lubricant, and fuel tank (generally designated 75) may be supported on the chassis 20.

[0036] The work vehicle 10 may include a compressor (not shown), such as a turbocharger, which compresses air into the combustion chamber of the engine 55 to increase the combustion efficiency and / or power output of the engine. During the air compression process in the compressor, the temperature of the air increases. An intercooler (such as a heat exchanger) may be coupled between the compressor and the engine 55 to reduce the temperature of the air, known as the boost air temperature, after the air passes through the compressor but before the air enters the engine 55.

[0037] The harvesting structure 80 may be coupled to the chassis 20. The illustrated harvesting structure 80 is configured to remove cotton from the field 35. The harvesting structure 80 may be a cotton stripper header 85( Figure 1 ), one or more cotton picking units 90( Figure 2 ) or another harvesting structure. Alternatively, the harvesting structure 80 may be configured to remove corn or another crop - for example, the harvesting structure 80 may be a corn header or a belt conveyor header (not shown).

[0038] Referring to Figure 1 and Figure 2 , an air duct system 95 may be coupled to the harvesting structure 80. A crop container 100 may be coupled to the air duct system 95. Referring to Figure 1 , the illustrated crop container 100 is a round module builder 105. Optionally, the crop container 100 may be a basket (not shown). The illustrated round module builder 105 includes a cleaner 108 that cleans the cotton harvested from the cotton stripper header 85 by removing trash and debris. Referring to Figure 2 , the round module builder 105 includes a collector 110 that is configured to receive cotton or other crops harvested by the cotton picking units 90.

[0039] Continuing to refer to Figure 2 , a feeder 115 may be coupled to the chassis 20. The feeder 115 is configured to receive cotton or other crops from the collector 110. The feeder 115 includes a plurality of rollers 120 that are configured to compress the cotton or other crops and transfer the cotton or other crops to the baler 125 of the round module builder 105.

[0040] As Figure 2As shown, the work vehicle 10 includes a clutch sensor 150, a ground speed sensor 152, an environmental sensor 155, an engine speed sensor 160, a cooling system sensor 162, and a fan control module 165. The clutch sensor 150 monitors the state of a clutch (such as a separator clutch or a cotton fan clutch) (not shown) of the work vehicle 10. The output of the clutch sensor 150 can indicate whether the clutch is engaged or disengaged. The ground speed sensor 152 measures the speed of the work vehicle relative to the ground on which the work vehicle 10 travels. The environmental sensor 155 measures the ambient air temperature of the work vehicle 10. The engine speed sensor 160 measures the speed of the engine 55, such as the revolutions per minute (RPM) of the engine 55. The cooling system sensor 162 measures one or more parameters of the cooling system (not shown) of the work vehicle 10, such as coolant temperature, charge air temperature, oil temperature, and refrigerant pressure. The operator interface 45, the variable pitch fan 70, the clutch sensor 150, the ground speed sensor 152, the environmental sensor 155, the engine speed sensor 160, the cooling system sensor 162, and the fan control module 165 can exchange data (such as parameters and instructions) through a network 166 (such as a controller area network). The network 166 can include one or more data buses.

[0041] Figure 4 is a functional block diagram of an example implementation of the variable pitch fan control system 400. As Figure 4 shown, the variable pitch fan control system 400 can include a fan control module 165, an operator interface 45, a variable pitch fan 70, and a blade pitch data storage device 405. The fan control module 165 can include a blade pitch module 402, a reverse module 408, an automatic reverse prevention module 411, a manual reverse prevention module 414, a clutch timer module 418, a maximum pitch module 422, a maximum pitch timer module 430, a reverse interval timer module 434, a vehicle status module 438, an engine status module 442, and a cooling system status module 450.

[0042] In various examples, the fan control module 165 can be an independent module in the work vehicle 10, as Figure 2as shown in the example of. In other examples, at least one of the blade pitch module 402, the reverse module 408, the automatic reverse prevention module 411, the manual reverse prevention module 414, the clutch timer module 418, the maximum pitch module 422, the maximum pitch timer module 430, the reverse interval timer module 434, the vehicle status module 438, the engine status module 442, and the cooling system status module 450 can be implemented independently or in conjunction with one or more other modules of the work vehicle 10, such as an engine control module (ECM), a transmission control module (TCM), or a powertrain control module (PCM).

[0043] Referring Figure 3 and Figure 4 , the fan control module 165 controls the pitch 135 of the multiple fan blades 140 of the variable pitch fan 70. The variable pitch fan 70 is directly or indirectly driven by the engine 55 of the work vehicle 10. The variable pitch fan 70 generates an air flow in a first direction 145. The blade pitch module 402 adjusts the pitch 135 of the multiple fan blades 140 based on one or more measured parameters of the cooling system of the work vehicle 10 - for example, coolant temperature, boost air temperature, ambient air temperature, and pressure associated with the heating, ventilation, and air conditioning (HVAC) system of the work vehicle 10. In some embodiments, the blade pitch module 402 receives the values of the measured cooling system parameters from the cooling system sensors 162 via the network 166. In other embodiments, the blade pitch module 402 can directly receive the measured parameters from the cooling system sensors 162.

[0044] The blade pitch module 402 determines the pitch 135 based on at least one of the measured cooling system parameters and a predetermined target value associated with the parameter. In some embodiments, the blade pitch module 402 can include a proportional-integral-derivative (PID) controller that determines the pitch 135 of the variable pitch fan 70. In other embodiments, the blade pitch module 402 can use a look-up table that includes a list of possible parameter values and corresponding pitch angles.

[0045] The reverse module 408 can command the vane pitch module 402 to perform fan reversal - for example, temporarily changing the pitch 135 of the plurality of fan blades 140 so that the air flow flows in a second direction 170 opposite to the first direction 145 before restoring the air flow to flow in the first direction 145. The change in the air flow direction can remove debris from the cooling system, thereby improving the efficiency of the cooling system. The reverse module 408 selectively commands automatic fan reversal in response to determining that one or more operating conditions associated with the work vehicle 10 exist. For example, the reverse module 408 can command fan reversal in response to determining that the automatic reversal prevention module 411 indicates that fan reversal is permitted, and the clutch of the work vehicle 10 has been engaged for at least a first period, the measured cooling system parameters exceed a threshold, or the variable pitch fan 70 has been operating at maximum pitch during a second period. In some embodiments, the reverse module 408 can generate an alert in response to not commanding fan reversal, such as a message displayed on the operator interface 45. The alert may indicate one or more conditions that prevent fan reversal.

[0046] In some embodiments, the reverse module 408 can command fan reversal based on the state of the clutch disengaged reverse status flag in response to the clutch transitioning from engaged to disengaged. For example, when the value of the clutch disengaged reverse status flag is true (enabled), the reverse module 408 can command automatic fan reversal in response to the clutch transitioning from engaged to disengaged. In some embodiments, the clutch disengaged reverse status flag can be set to a predetermined value. In other embodiments, the clutch disengaged reverse status flag can be set to an initial value, and an operator of the work vehicle 10 can change the value of the clutch disengaged reverse status flag - for example, via the operator interface 45 - to disable or enable automatic clutch disengaged fan reversal.

[0047] The reverse module 408 selectively commands manual fan reversal in response to a request from an operator of the work vehicle 10 to reverse the fan. The reverse module 408 commands manual fan reversal in response to receiving an instruction to reverse the variable pitch fan 70 from the operator (e.g., via the operator interface 45) and determining that the manual reversal prevention module 414 indicates that manual fan reversal is permitted. In some embodiments, the reverse module 408 can generate an alert in response to not commanding fan reversal, such as a message displayed on the operator interface 45. The alert may indicate one or more conditions that prevent fan reversal.

[0048] In response to a command to reverse the fan (automatically or manually), the reverse module 408 can generate an alert to notify the operator of the work vehicle 10 that the air flow direction associated with the variable pitch fan 70 has been temporarily reversed. For example, the reverse module 408 can generate and display on the operator interface 45 a message indicating that the fan reversal is occurring. The reverse module 408 can also generate an alert notifying the operator of the work vehicle 10 that fan reversal is not currently permitted. For example, in response to the automatic reverse prevention module 411 indicating that automatic fan reversal is not permitted, the reverse module 408 can generate and display on the operator interface 45 a message indicating that automatic fan reversal is not currently permitted. The generated message can indicate one or more conditions currently preventing automatic fan reversal. Similarly, in response to the manual reverse prevention module 414 indicating that manual reversal is not permitted, the reverse module 408 can generate and display on the operator interface 45 a message indicating that manual fan reversal is not currently permitted. The generated message can indicate one or more conditions currently preventing manual fan reversal.

[0049] The clutch timer module 418 generates a first timer value that indicates how long (i.e., the period) the clutch of the work vehicle 10 (e.g., the separator clutch or the cotton fan clutch) has been engaged since the reverse module 408 last commanded the fan to reverse. When the clutch is engaged, the clutch timer module 418 increments the first timer. When the reverse module 408 commands the fan to reverse, the clutch timer module 418 resets the first timer.

[0050] The clutch timer module 418 compares the first timer value with a first period (or value) and outputs the result of the comparison to the reverse module 408. In some embodiments, the first period is a predetermined period. For example, the first period can be or correspond to approximately 15 minutes. In other embodiments, the first period can be set to an initial period, such as 15 minutes, and the operator of the work vehicle 10 can change the first period to another suitable period via the operator interface 45. Thus, the output of the clutch timer module 418 indicates whether the clutch has been engaged for at least the first period since the last command to reverse the fan.

[0051] The maximum pitch module 422 determines the operating state of the variable pitch fan 70 based on the current pitch of the blade 140 (e.g., pitch 135) and the measured ambient temperature. The maximum pitch module 422 receives the measured ambient temperature from the ambient sensor 155. The maximum pitch module 422 uses the blade pitch data storage device 405 to determine the maximum blade pitch for the measured ambient temperature. The blade pitch data storage device 405 includes a list of possible ambient temperatures. Each listed ambient temperature is associated with a maximum blade pitch. The maximum pitch module 422 retrieves from the blade pitch data storage device 405 the maximum blade pitch associated with the measured ambient temperature.

[0052] In some embodiments, the maximum pitch module 422 provides the retrieved maximum blade pitch to the blade pitch module 402. The blade pitch module 402 may set the pitch 135 of the plurality of fan blades 140 to the received maximum blade pitch in response to one of the received cooling system parameters exceeding a cooling system threshold. In various embodiments, the blade pitch module 402 may receive one or more fault codes associated with the cooling system - e.g., a diagnostic trouble code (DTC). In response to receiving a fault code (e.g., a DTC indicating an open circuit associated with the cooling system sensor 162), the blade pitch module 402 may set the pitch 135 of the plurality of fan blades 140 to the received maximum blade pitch. In response to each received fault code, the blade pitch module 402 may not set the pitch 135 to the received maximum blade pitch. By way of example only, in response to receiving a DTC indicating a blade pitch sensor fault or a hydraulic solenoid valve driver fault, the blade pitch module 402 does not set the pitch 135 to the received maximum blade pitch.

[0053] The maximum pitch module 422 receives the current pitch of the blade 140 from the blade pitch module 402 and compares the current pitch with the retrieved maximum blade pitch. When the current pitch is greater than or equal to the retrieved maximum blade pitch, the maximum pitch module 422 determines that the variable pitch fan 70 is operating at maximum pitch. When the current pitch is less than the retrieved maximum blade pitch, the maximum pitch module 422 determines that the variable pitch fan 70 is not operating at maximum pitch. The maximum pitch module 422 provides the determined operating state of the variable pitch fan 70 to the reverse module 408 and the maximum pitch timer module 430.

[0054] The maximum pitch timer module 430 generates a second timer value that indicates how long (i.e., the period) the variable pitch fan 70 has been operating continuously at maximum pitch. When the maximum pitch module 422 indicates that the variable pitch fan 70 is not operating at maximum pitch, the maximum pitch timer module 430 resets the second timer value. When the maximum pitch module 422 indicates that the variable pitch fan 70 is operating at maximum pitch, the maximum pitch timer module 430 increments the second timer.

[0055] The maximum pitch timer module 430 compares the second timer value with a second predetermined period (or value) and outputs the result of the comparison to the reverse module 408. For example, the second predetermined period can be or correspond to about 2 minutes or another suitable period. Thus, the output of the maximum pitch timer module 430 indicates whether the variable pitch fan 70 has been operating continuously at maximum pitch for at least the second predetermined period of time. In some embodiments, the reverse module 408 can command fan reversal in response to determining that automatic fan reversal is permitted, the variable pitch fan 70 is operating at maximum pitch, and the measured cooling system parameter is greater than a trigger threshold. By way of example only, when the automatic reverse prevention module 411 indicates that fan reversal is permitted, the maximum pitch module 422 indicates that the variable pitch fan 70 is operating at maximum pitch, and the measured coolant temperature is greater than 103 degrees Celsius, the reverse module 408 can command fan reversal.

[0056] The reverse interval timer module 434 generates a third timer value that indicates the length of time (i.e., the period) since the reverse module 408 last commanded fan reversal. The reverse interval timer module 434 resets and then continuously increments the third timer value in response to the reverse module 408 commanding fan reversal. The reverse interval timer module 434 compares the third timer value with a third predetermined period (or value) and outputs the result of the comparison to the automatic reverse prevention module 411 and the manual reverse prevention module 414. In some embodiments, the third predetermined period can be or correspond to 120 seconds. In other embodiments, the third predetermined period can be or correspond to 150 seconds or other suitable period. Thus, the output of the reverse interval timer module 434 indicates whether a length of time equal to or greater than the third predetermined period has elapsed since the last commanded fan reversal.

[0057] The vehicle status module 438 determines the operating status of the work vehicle 10 based on one or more of the ground speed of the work vehicle 10 received from the ground speed sensor 152, the status of the clutch received from the clutch sensor 150, and the status of the transmission of the work vehicle 10. In some embodiments, the vehicle status module 438 may receive the status of the transmission via the network 166 - for example, from a transmission control module (TCM, not shown). In other embodiments, the vehicle status module 438 may receive the status of the transmission directly from a sensor (not shown) associated with the transmission.

[0058] The vehicle status module 438 compares the received ground speed with a first speed threshold. In some embodiments, the first speed threshold may be or correspond to 0.8 kph. In other embodiments, the second speed threshold may be or correspond to 1 kph or other suitable speed. In response to the ground speed being less than the first speed threshold, the vehicle status module 438 determines that the work vehicle 10 is operating in a stationary state.

[0059] In some embodiments, the vehicle status module 438 may compare the received ground speed with a second speed threshold. The second speed threshold may be or correspond to 7 kph. Alternatively, the second speed threshold may be or correspond to 10 kph or another suitable speed. In response to the ground speed exceeding the second speed threshold and the clutch sensor 150 indicating that the clutch is disengaged, the vehicle status module 438 determines that the work vehicle 10 is operating in an estimated road condition. In other embodiments, the vehicle status module 438 may determine that the work vehicle 10 is operating in an estimated road condition in response to the clutch sensor 150 indicating that the clutch is disengaged and the status of the transmission indicating that the hydrostatic transmission is not in neutral and the transmission is in a high gear range.

[0060] The vehicle status module 438 provides the determined operating status of the work vehicle 10 to the manual reverse prevention module 414. In some embodiments, the vehicle status module 438 may also provide the determined operating status of the work vehicle 10 to the automatic reverse prevention module 411.

[0061] The engine status module 442 determines the operating status of the engine 55 based on the speed of the engine 55 measured by the engine speed sensor 160. When the engine speed is less than or equal to a first predetermined engine speed, the engine status module 442 determines that the engine 55 is in an ultra-low idle state. When the engine speed is greater than the first predetermined engine speed and less than or equal to a second predetermined engine speed, the engine status module 442 determines that the engine is in a below-medium idle state. When the engine speed is greater than a third predetermined engine speed, the engine status module 442 determines that the engine 55 is in an overspeed state. By way of example only, the first, second, and third predetermined engine speeds may be 650 revolutions per minute (RPM), 1500 RPM, and 2130 RPM, respectively. In other examples, the first, second, and third predetermined engine speeds may be other suitable speeds associated with the engine 55. The engine status module 442 provides the determined operating status of the engine 55 to both the automatic anti-reversal module 411 and the manual anti-reversal module 414.

[0062] The cooling system status module 450 may receive one or more fault codes associated with the cooling system, such as diagnostic trouble codes (DTCs). In some embodiments, the cooling system status module 450 receives one or more fault codes via the network 166. In other embodiments, the cooling system status module 450 may receive fault codes directly from the component of the cooling system that generates the fault codes. In response to receiving at least one fault code, the cooling system status module 450 determines that the cooling system is in an error state. In response to not receiving any fault codes, the cooling system status module 450 determines that the cooling system is operating in a normal state. The cooling system status module 450 provides the determined operating status of the cooling system to the automatic reversal prevention module 411 and the manual reversal prevention module 414.

[0063] The automatic reversal prevention module 411 determines whether to allow automatic fan reversal based on one or more conditions and provides an indication of the determination to the reversal module 408. In response to the reversal interval timer module 434 indicating that a time period greater than or equal to a third predetermined time period has not elapsed since the last commanded fan reversal, the automatic reversal prevention module 411 determines that automatic fan reversal is not allowed. In response to the engine status module 442 indicating that the engine 55 is operating in an ultra-low idle state, a below-medium idle state, or an overspeed state, the automatic reversal prevention module 411 determines that automatic fan reversal is not allowed. Performing fan reversal while the engine is operating in an ultra-low idle state may cause damage to the variable pitch fan 70 due to reduced oil flow. Performing fan reversal while the engine 55 is operating in an overspeed state may cause a fan hub spring failure.

[0064] The automatic reverse prevention module 411 can determine that automatic fan reverse is not allowed in response to the vehicle status module 438 indicating that the work vehicle 10 is operating in a stationary state. In response to receiving an indication from the cooling system status module 450 that the cooling system is operating in an error state, the automatic reverse prevention module 411 determines that automatic fan reverse is not allowed.

[0065] The automatic reverse prevention module 411 can allow automatic reverse while the work vehicle 10 is operating in an actual or estimated road or transport mode based on the status of the automatic road reverse status flag. For example, the automatic reverse prevention module 411 can allow automatic reverse when the value of the automatic road reverse status flag is true (enabled), and prevent automatic reverse when the value of the automatic road reverse status flag is false (disabled). In some embodiments, the automatic road reverse status flag can be set to a predetermined value. In other embodiments, the automatic road reverse status flag can be set to an initial value, and an operator of the work vehicle 10 can change the value of the automatic road reverse status flag - for example, via the operator interface 45 - to disable or enable automatic road reverse. In response to determining that the road reverse status flag is false, and determining that the current mode of the work vehicle 10 is a road mode or the vehicle status module 438 indicates that the operating state of the work vehicle 10 is an estimated road state, the automatic reverse prevention module 411 determines that automatic fan reverse is not allowed.

[0066] The manual reverse prevention module 414 determines whether to allow manual fan reverse based on one or more conditions and provides an indication of the determination to the reverse module 408. In response to the reverse interval timer module 434 indicating that a time duration greater than or equal to a third predetermined time period has not elapsed since the last commanded fan reverse, the manual reverse prevention module 414 determines that manual fan reverse is not allowed. In response to the engine status module 442 indicating that the engine 55 is operating in an ultra-low idle state or an overspeed state, the manual reverse prevention module 414 determines that manual fan reverse is not allowed.

[0067] The manual reverse prevention module 414 can determine that manual fan reverse is not allowed in response to the vehicle status module 438 indicating that the work vehicle 10 is operating in a stationary state. In response to receiving an indication from the cooling system status module 450 that the cooling system is operating in an error state, the manual reverse prevention module 414 determines that manual fan reverse is not allowed.

[0068] The manual reverse prevention module 414 may allow manual reverse while the work vehicle 10 is operating in a road or transport mode based on the status of the manual road reverse status flag. For example, the manual reverse prevention module 414 may allow manual reverse when the value of the manual road reverse status flag is true (enabled), and prevent manual reverse when the value of the manual road reverse status flag is false (disabled). In some embodiments, the manual road reverse status flag may be set to a predetermined value. In other embodiments, the manual road reverse status flag may be set to an initial value, and an operator of the work vehicle 10 may change the value of the manual road reverse status flag - for example, via the operator interface 45 - to disable or enable manual road reverse.

[0069] The manual reverse prevention module 414 may receive the current mode of the work vehicle 10 via the network 166. In response to determining that the manual road reverse flag is false and the current mode of the work vehicle 10 is the road mode or the vehicle status module 438 indicates that the operating status of the work vehicle 10 is an estimated road status, the manual reverse prevention module 414 determines that manual fan reverse is not allowed.

[0070] In various embodiments, the automatic reverse prevention module 411 and the manual reverse prevention module 414 may receive an indication of the ambient temperature of the work vehicle 10 from the ambient sensor 155. The automatic reverse prevention module 411 and the manual reverse prevention module 414 each compare the received ambient temperature with a temperature threshold. In some embodiments, the temperature threshold is a predetermined value - for example, the temperature threshold may be or correspond to 0 degrees Celsius or another suitable temperature. In other embodiments, the temperature threshold may be set to an initial temperature - for example, 0 degrees Celsius - and an operator of the work vehicle 10 may change the temperature threshold to another suitable temperature via the operator interface 45. In response to the measured ambient temperature being less than the temperature threshold, the automatic reverse prevention module 411 determines that automatic fan reverse is not allowed. Similarly, in response to the measured ambient temperature being less than the temperature threshold, the manual reverse prevention module 414 determines that manual fan reverse is not allowed.

[0071] Figures 5A to 5C is a flowchart depicting an example method of controlling the reverse of a variable pitch fan, such as the variable pitch fan 70. In an example embodiment, the control may be performed by the fan control module 165. In other embodiments, the control may be performed by an engine control module (e.g., ECM) or a driveline module (e.g., PCM) of the work vehicle 10.

[0072] When the fan control module 165 is started (e.g., when the work vehicle 10 is powered on), the control begins at Figure 5AAt 501, the control sets the previously sensed state of the clutch of the work vehicle 10 (Clutch_Previous) to disengaged. Additionally, the control sets to zero a timer (Clutch_Timer) that tracks the length of time the clutch has been engaged, a timer (Pitch_Timer) that tracks the length of time the variable pitch fan 70 has been operating continuously at maximum pitch, and a timer (Reversal_Timer) that tracks the length of time since the last fan reversal (the reversal timer). The control proceeds to 504.

[0073] At 504, the control receives and stores a measured value of a cooling system parameter (Cooling_Param). For example, the vane pitch module 402 may receive the measured coolant or charge air temperature from the cooling system sensor 162. The control then determines the fan vane pitch based on the received cooling system parameter. For example, the vane pitch module 402 may determine an appropriate pitch for the vanes 140 of the variable pitch fan 70. The control stores the determined fan vane pitch as the current pitch (Pitch_Current). The control then proceeds to 507.

[0074] At 507, the control receives the measured speed of the engine 55 of the work vehicle 10 and determines the operating state of the engine 55 (e.g., Ultra_Low_Idle, Below_Mid_Idle, or Over_Speed) based on the measured engine speed. For example, the engine state module 442 may receive the speed of the engine 55 from the engine speed sensor 160. The control stores the determined operating state of the engine (Engine_State). The control proceeds to 510, where the control receives the sensed state of the clutch and stores that state as the current state of the clutch (Clutch_Current). The control proceeds to 513.

[0075] At 513, the control determines whether the clutch is currently engaged - for example, Clutch_Current is equal to engaged. If so, the control proceeds to 516; otherwise, the control transfers to 519. At 516, the control increments Clutch_Timer, and then the control proceeds to 522.

[0076] At 519, the control determines whether the previously sensed state of the clutch was engaged - for example, Clutch_Previous is equal to engaged. In other words, the control determines whether the clutch has recently disengaged. If so, the control proceeds to 525; otherwise, the control transfers to 522. At 525, the control changes the previously sensed state of the clutch to disengaged - for example, the control sets Clutch_Previous to disengaged. The control proceeds to 528.

[0077] At 528, the control determines whether automatic clutch disengaged fan reverse is enabled. For example, the reverse module 408 checks the value of the clutch disengaged reverse status flag. If 528 is true, the control proceeds to Figure 5C 531, as described below; otherwise, the control transfers to 522.

[0078] At Figure 5A 522, the control determines whether the clutch has been engaged for at least a first time period since the last fan reverse, e.g., Clutch_Timer is greater than or equal to a first threshold. If so, the control continues to Figure 5C 531; otherwise the control transfers to Figure 5B 537.

[0079] At Figure 5B 537, the control receives the measured ambient temperature and determines the maximum fan blade pitch (Max_Pitch) based on the measured ambient temperature. For example, the maximum pitch module 422 can receive the measured ambient temperature of the work vehicle 10 from the ambient sensor 155. The control continues to 543, where the control determines whether the fan is currently operating at maximum pitch - e.g., Pitch_Current is greater than or equal to Max_Pitch. If so, the control proceeds to 546; otherwise, the control transfers to 549. At 549, the control stops the timer associated with continuous maximum pitch. For example, the control sets Pitch_Timer to zero. The control then proceeds to Figure 5C 558, as described below.

[0080] At Figure 5B 546, the control increments the timer (Pitch_Timer) associated with continuous maximum pitch and then proceeds to 552. At 552, the control determines whether the measured cooling system parameter is greater than a second threshold - e.g., Cooling_Param is greater than 103 degrees Celsius. If 552 is true, the control transfers to Figure 5C 531; otherwise, the control proceeds to 555. At 555, the control determines whether the fan has been operating at maximum pitch for at least a second time period - e.g., Pitch_Timer is greater than or equal to a third threshold. If 555 is true, the control transfers to Figure 5C 531; otherwise, the control proceeds to Figure 5C 558.

[0081] At Figure 5C 531, the control determines whether the engine is operating at below mid idle - e.g., the engine status is equal to Below_Mid_Idle. If so, the control transfers to 561; otherwise the control proceeds to 564.

[0082] At 564, the control determines whether automatic fan reversal is allowed while the work vehicle 10 is in road mode. For example, the automatic reverse prevention module 411 checks the value of the automatic road reverse status flag. If 564 is true, the control proceeds to 567; otherwise, the control transfers to 570. In some embodiments, when the work vehicle 10 is in road mode or an estimated road condition, the control may prevent automatic fan reversal, and if 564 is false, the control transfers to 588 instead of 570.

[0083] At 567, the control determines whether the ambient temperature of the work vehicle 10 is less than a temperature threshold - for example, Ambient_Temp is less than a fourth threshold. If 567 is true, the control transfers to 561; otherwise, the control proceeds to 571. At 571, the control determines the current state of the cooling system (Cooling_State) - for example, normal or error. For example, in response to receiving at least one DTC associated with the cooling system, the cooling system status module 450 determines that the cooling system is in an error state. At 573, if the control determines that the current state of the cooling system (Cooling_State) is equal to Error, the control transfers to 561; otherwise, the control proceeds to 576.

[0084] At 576, the control determines whether at least a third time period has elapsed since the variable pitch fan 70 was last reversed. For example, the control determines whether Reversal_Timer is greater than or equal to a fifth threshold. If so, the control proceeds to 579; otherwise, the control transfers to 561. At 579, the control determines whether the engine is currently operating at an ultra-low idle or an extremely high speed - for example, Engine_State is equal to Ultra_Low_Idle or Over_Speed. If 579 is true, the control transfers to 561; otherwise, the control proceeds to 582.

[0085] At 582, the control adjusts the pitch 135 of the blades of the variable pitch fan 70 to temporarily change the direction of the air flow generated by the variable pitch fan 70 from a first direction to a second direction. The control resets the timer associated with clutch engagement, the timer associated with the fan operating continuously at maximum pitch, and the timer associated with the last fan reversal. For example, the control sets Clutch_Timer, Pitch_Timer, and Reversal_Timer to zero. The control may also generate an alarm indicating a commanded fan reversal. For example, the reversal module 408 may display a message on the operator interface 45 stating that the fan reversal is occurring. The control then returns to Figure 5A 504.

[0086] Back to Figure 5CAt 558, the control determines whether the operator of the work vehicle has requested fan reverse - in other words, whether the operator has performed a manual fan reverse. For example, the reverse module 408 determines whether the operator has initiated a fan reverse via the operator interface 45. If 558 is true, the control proceeds to 585; otherwise, the control transfers to 561.

[0087] At 585, the control determines whether manual fan reverse is allowed when the work vehicle 10 is in road mode or an estimated road condition. For example, the manual reverse prevention module 414 checks the value of the manual road reverse status flag. If 585 is true, the control continues to 567; otherwise, the control transfers to 588. At 588, the control receives the measured ground speed of the work vehicle and determines the vehicle state (Vehicle_State) based on the measured ground speed and the sensed state of the clutch. For example, in response to determining that the measured ground speed from the ground speed sensor 152 is greater than or equal to 7 kph and the clutch is disengaged, the vehicle state module 438 determines that the work vehicle 10 is operating in an estimated road condition (Road_Est). At 591, the control determines whether the vehicle state is the estimated road mode - for example, Vehicle_State = Road_Est. If so, the control transfers to 561; otherwise the control proceeds to 567.

[0088] Back to Figure 5C At 561, the control determines that fan reverse (automatic or manual) has not been initiated or alternatively is blocked. Accordingly, fan reverse is not performed and a timer associated with fan reverse (Reversal_Timer) is incremented. At 561, the control may also generate an alert that fan reverse is blocked. For example, in response to an operator request for manual fan reverse and the manual reverse prevention module 414 determining that manual fan reverse is not allowed, the reverse module 408 may display a message on the operator interface 45 regarding the blocked fan reverse. This information may include one or more of the circumstances that caused the fan reverse to be blocked, such as, for example, excessive engine speed. The control then returns to Figure 5A 504 of

[0089] The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or its use. The broad teachings of the disclosure can be implemented in a variety of forms. Thus, while the disclosure includes specific examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the appended claims. It should be understood that one or more steps in a method can be performed in a different order (or concurrently) without altering the principles of the disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any one embodiment of the disclosure can be implemented in and / or combined with the features of any of the other embodiments, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more of the embodiments with each other are still within the scope of the disclosure.

[0090] Spatial and functional relationships between elements (e.g., relationships between modules, circuit elements, semiconductor layers, etc.) are described using a variety of terms, including "connected," "engaged," "coupled," "adjacent," "near," "on," "above," "below," and "disposed." Unless explicitly described as "direct," when describing the relationship between a first and a second element in the foregoing disclosure, the relationship can be a direct relationship with no other intervening elements between the first and second elements, but can also be an indirect relationship with one or more intervening elements (spatially or functionally) between the first and second elements.

[0091] As used herein, the phrase "at least one of A, B, and C" should be construed to mean a logical (A or B or C) using a non-exclusive logical "or," and should not be construed to mean "at least one of A, at least one of B, and at least one of C." A subset of terms does not necessarily require a proper subset. In other words, a first subset of a first set can be coextensive with (equal to) the first set.

[0092] In the figures, the direction of an arrow (as shown by the arrowhead) generally represents the flow of information of interest in the illustration (such as data or instructions). For example, when elements A and B exchange various information, but the information transmitted from element A to element B is relevant to the illustration, the arrow can point from element A to element B. This one-way arrow does not mean that no other information is transmitted from element B to element A. Further, for the information sent from element A to element B, element B can send a request for that information to element A or receive its confirmation.

[0093] In this application, the following definitions are included. The term "module" or the term "controller" may be replaced by the term "circuit". The term "module" may refer to, be part of, or include the following: application specific integrated circuit (ASIC); digital, analog, or mixed analog / digital discrete circuit; digital, analog, or mixed analog / digital integrated circuit; combinational logic circuit; field programmable gate array (FPGA); processor circuitry that executes code (shared processor circuitry, dedicated processor circuitry, or group processor circuitry); memory circuitry that stores code executed by the processor circuitry (shared memory circuitry, dedicated memory circuitry, or group memory circuitry); other suitable hardware components that provide the functionality; or a combination of some or all of the above, such as in a system on a chip.

[0094] Some or all of the hardware characteristics of a module may be defined using a hardware description language, such as IEEE standard 1364-2005 (commonly known as "Verilog") and IEEE standard 1076-2008 (commonly known as "VHDL"). The hardware description language may be used to fabricate and / or program the hardware circuit. In some embodiments, some or all of the characteristics of a module may be defined by a language, such as IEEE 1666-2005 (commonly known as "SystemC"), which includes both code and hardware description as described below.

[0095] As used above, the term code may include software, firmware, and / or microcode, and may refer to programs, routines, functions, classes, data structures, and / or objects. The term shared processor circuitry encompasses a single processor circuitry that executes some or all of the code from multiple modules. The term group processor circuitry encompasses processor circuitry that, in combination with additional processor circuitry, executes some or all of the code from one or more modules. References to multiple processor circuitries include multiple processor circuitries on separate dies, multiple processor circuitries on a single die, multiple cores of a single processor circuitry, multiple threads of a single processor circuitry, or a combination of the above. The term shared memory circuitry encompasses a single memory circuitry that stores some or all of the code from multiple modules. The term group memory circuitry encompasses memory circuitry that, in combination with additional memory, stores some or all of the code from one or more modules.

[0096] The term memory circuit is a subset of the term computer-readable medium. As used herein, the term computer-readable medium does not encompass transient electrical or electromagnetic signals that are propagated through a medium (such as on a carrier wave); thus, the term computer-readable medium can be considered tangible and non-transitory. Non-limiting examples of non-transitory computer-readable media are non-volatile memory circuits (such as flash memory circuits, erasable programmable read-only memory circuits, or mask read-only memory circuits), volatile memory circuits (such as static random access memory circuits or dynamic random access memory circuits), magnetic storage media (such as analog or digital magnetic tape or hard disk drives), and optical storage media (such as CDs, DVDs, or Blu-ray discs).

[0097] The devices and methods described in this application can be implemented in part or in whole by a special-purpose computer created by configuring a general-purpose computer to perform one or more specific functions embodied in a computer program. The above functional blocks and flowchart elements serve as software specifications that can be translated into a computer program by the routine work of a skilled technician or programmer.

[0098] A computer program includes processor-executable instructions stored on at least one non-transitory computer-readable medium. The computer program may also include or rely on stored data. The computer program can encompass a basic input / output system (BIOS) that interacts with the hardware of the special-purpose computer, device drivers that interact with specific devices of the special-purpose computer, one or more operating systems, user applications, background services, background applications, etc.

[0099] A computer program can include: (i) descriptive text to be parsed, such as HTML (Hypertext Markup Language), XML (eXtensible Markup Language), or JSON (JavaScript Object Notification), (ii) assembly code, (iii) object code generated from source code by a compiler, (iv) source code for execution by an interpreter, (v) source code for compilation and execution by a just-in-time compiler, and so on. By way of example only, source code can be written using languages from including C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Fortran, Perl, Pascal, Curl, OCaml, HTML5 (Hypertext Markup Language Fifth Edition), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Visual Lua, MATLAB, SIMULINK, and written in the grammar of the language.

[0100] None of the elements recited in the claims are intended to be apparatus - plus - function elements within the meaning of 35 U.S.C.§122(F), unless the element is expressly recited using the phrase "means for" or, in the case of a method claim, the phrase "operation for" or "step for".

Claims

1. A fan control system for a variable pitch fan of a work vehicle, the fan control system comprising: A first sensor that measures a parameter of a cooling system of the work vehicle; A blade pitch module configured to: Receive the measured parameter from the first sensor, and Adjust the pitch of a plurality of blades of the variable pitch fan based on the measured parameter to generate a first air flow in a first direction; A reverse module configured to selectively command the fan to reverse, the fan reversal including instructing the blade pitch module to temporarily adjust the pitch of the plurality of blades of the variable pitch fan to generate a second air flow in a second direction; A first timer module configured to: Reset and increment a first timer in response to the reverse module commanding the fan to reverse, and Compare the first timer with a first threshold; A first reverse prevention module configured to prevent the reverse module from commanding the fan to reverse by indicating that a first type of fan reversal is not allowed in response to determining that the first timer is less than the first threshold, and A second reverse prevention module configured to prevent the reverse module from commanding the fan to reverse by indicating that a second type of fan reversal is not allowed in response to determining that the first timer is less than the first threshold, wherein the reverse module is configured to: Receive, via an operator interface, an instruction requesting a second type of fan reversal, and Command the fan to reverse in response to (i) receiving the instruction and (ii) determining that the second reverse prevention module does not indicate that the second type of fan reversal is not allowed.

2. The fan control system according to claim 1, further comprising: A second sensor that monitors a state of a clutch of the work vehicle; And A second timer module configured to: Receive the state of the clutch from the second sensor, Increment a second timer in response to the state of the clutch indicating that the clutch is engaged, and Compare the second timer with a second threshold, wherein the reverse module is configured to command the fan to reverse in response to determining (i) that the second timer is equal to or greater than the second threshold and (ii) that the first reverse prevention module does not indicate that the first type of fan reversal is not allowed.

3. The fan control system according to claim 1, wherein the work vehicle includes an engine, and the fan control system further comprises: A second sensor that measures a speed of the engine; And An engine state module configured to: Receive the measured engine speed from the second sensor, Compare the measured engine speed with a first speed threshold, and Compare the measured engine speed with a second speed threshold, wherein: The first reverse prevention module is configured to indicate that the first type of fan is not allowed to reverse in response to determining (i) that the measured engine speed is less than the first speed threshold or (ii) that the measured engine speed is greater than the second speed threshold, and the first speed threshold is less than the second speed threshold.

4. The fan control system according to claim 3, wherein the engine state module is configured to compare the measured engine speed with a third speed threshold, and the fan control system further comprises: a second reverse prevention module configured to prevent the reverse module from commanding the fan to reverse by indicating that the second type of fan is not allowed to reverse in response to determining (i) that the engine speed is less than the third speed threshold or (ii) that the engine speed is greater than the first speed threshold, wherein: the reverse module is configured to: receive, via an operator interface, an instruction requesting the second type of fan to reverse, and command the fan to reverse in response to (i) receiving the instruction and (ii) determining that the second reverse prevention module does not indicate that the second type of fan is not allowed to reverse, and the third speed threshold is less than both the first speed threshold and the second speed threshold.

5. The fan control system according to claim 1, further comprising: a third sensor that measures the ambient temperature associated with the work vehicle, wherein the first reverse prevention module is configured to: receive the measured ambient temperature from the third sensor, and indicate that the first type of fan is not allowed to reverse in response to determining that the received ambient temperature is less than a temperature threshold.

6. The fan control system according to claim 1, further comprising: a cooling system status module configured to: set the status of the cooling system based on at least one code associated with one or more components of the cooling system, and set the status of the cooling system to an error status in response to receiving at least one fault code, wherein the first reverse prevention module is configured to indicate that the first type of fan is not allowed to reverse in response to determining that the cooling system is in an error status.

7. A method for controlling a variable pitch fan of a work vehicle, the method comprising: measuring a parameter of the cooling system of the work vehicle; performing a first type of fan reverse, including temporarily adjusting the pitch of a plurality of blades of the variable pitch fan to generate a second air flow in a second direction; resetting and incrementing a first timer in response to performing the first type of fan reverse; comparing the first timer with a first threshold; preventing a second type of fan from reversing in response to determining that the first timer is less than the first threshold, and performing a second type of fan reverse in response to (i) receiving a reverse request from an operator of the work vehicle and (ii) determining that the first timer is greater than the first threshold.

8. The method according to claim 7, further comprising: receiving the status of a clutch of the work vehicle from a second sensor; In response to performing the reverse rotation of the first type of fan, reset the second timer; In response to the state of the clutch indicating that the clutch is engaged, increment the second timer; Compare the second timer with a second threshold; In response to determining that the first timer is greater than the first threshold and the second timer is greater than the second threshold, perform the reverse rotation of the second type of fan.

9. The method according to claim 7, wherein the work vehicle includes an engine, and the method includes: Measure the speed of the engine; Compare the measured engine speed with a first speed threshold; Compare the measured engine speed with a second speed threshold; And In response to determining (i) that the first timer is greater than the first threshold, (ii) that the measured engine speed is greater than the first speed threshold, and (iii) that the measured engine speed is less than the second speed threshold, perform the reverse rotation of the second type of fan, wherein the first speed threshold is less than the second speed threshold.

10. The method according to claim 9, further comprising: Compare the measured engine speed with a third speed threshold; And Perform the reverse rotation of the second type of fan in response to: Receiving a reverse request from an operator of the work vehicle; and Determining (i) that the first timer is greater than the first threshold, (ii) that the measured engine speed is greater than the third speed threshold, and (iii) that the measured engine speed is less than the second speed threshold, wherein the third speed threshold is less than both the first speed threshold and the second speed threshold.

11. The method according to claim 7, further comprising: Receive the ambient temperature associated with the work vehicle from a third sensor; Compare the received ambient temperature with a temperature threshold; And In response to determining that the first timer is greater than the first threshold and the received ambient temperature is greater than the temperature threshold, perform the reverse rotation of the second type of fan.

12. The method according to claim 8, further comprising: Determine the cooling state of the cooling system based on at least one code associated with one or more components of the cooling system; And In response to determining (i) that the first timer is greater than the first threshold, (ii) that the second timer is greater than the second threshold, and (iii) that the cooling state is not an error state, perform the reverse rotation of the second type of fan.

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