Work vehicle with debris collector load compensator

Abstract

The work vehicle 100 includes an internal combustion engine 102 and a traction unit 104 driven by the internal combustion engine. The vehicle has a debris collection unit 200 with a fan 204 and duct 2

Description

SUMMARY

[0001] The present disclosure is directed to work machine platforms such as mowers, sweepers, snow-throwers, aerators, trenchers, edgers, and the like. In one embodiment, a work vehicle includes an internal combustion engine and a traction unit driven by the internal combustion engine. The vehicle has a debris collection unit with a fan and duct configured to collect debris from a work region. The debris collection unit further includes a fan motor that drives the fan. The fan motor is powered by the internal combustion engine. A controller of the vehicle is operable to measure a speed of the fan motor while the work vehicle is being moved by the traction unit and the debris collection unit is collecting the debris. In response to detecting debris loading on the fan motor, the controller increases an input to the fan motor to compensate thereto. In response to the increase of the input to the fan motor, the controller restricts a maximum speed of the traction unit.

[0002] In another embodiment, a controller-implemented method of regulating operation of a work vehicle involves moving the work vehicle along a work region via a traction unit. The traction unit is driven by an internal combustion engine. While the work vehicle is moving, debris is collected via a debris collection unit that includes: a fan; a duct; and a fan motor that drives the fan. The fan motor is powered by the internal combustion engine. In response to detecting debris loading of the fan, an input to the fan motor is increased to compensate thereto. In response to the increase of the input to the fan motor, a maximum speed of the traction unit is restricted.

[0003] These and other features and aspects of various embodiments may be understood in view of the following detailed discussion and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The discussion below makes reference to the following figures, wherein the same reference number may be used to identify the similar / same component in multiple figures. The drawings are not necessarily to scale.

[0005] FIG. 1 is a side view of a work / utility vehicle according to an example embodiment;

[0006] FIG. 2 is a cutaway view of the work utility of FIG. 1;

[0007] FIGS. 3, 4A and 4B are respective side and front views showing details of a debris collection unit according to various embodiments;

[0008] FIG. 5 is a flowchart of a method according to an example embodiment;

[0009] FIGS. 6-11 are block diagrams showing settings and modes of a work machine according to various embodiments;

[0010] FIG. 12 is a block diagram of a control system according to an example embodiment; and

[0011] FIG. 13 is a flowchart of a method according to another example embodiment. DETAILED DESCRIPTION

[0012] In the following detailed description of illustrative embodiments, reference is made to the accompanying figures of the drawing which form a part hereof. It is to be understood that other equivalent embodiments, which may not be described and / or illustrated herein, are also contemplated.

[0013] Grounds maintenance work vehicles such as lawn mowers are used by consumers and professional alike. These vehicles are typically configured as either walk-behind or ride-on vehicles having an implement (e g., a grass cutting deck) attached thereto. Generally, the work vehicle includes a chassis / frame which includes a traction unit that moves the unit, e g., by rotating wheels or continuous treads. The traction unit is often powered by an internal combustion engine (ICE), although electrically-powered or hybrid work machines are increasingly becoming available.

[0014] The work vehicle may have a fixed or swappable work implement, such as a mower, brush, tiller, aerator, or the like. Often, the work vehicle has a power takeoff (PTO) to power the work implement. The PTO can be selectively engaged with or disengaged from the engine. The work vehicle may also include other devices that draw power from the engine, e g., hydraulic pumps, electrical generators, pneumatic pumps, etc., that provide power to other components on the vehicle.

[0015] While an ICE-powered vehicle can be provided with an engine with large amounts of available power, other considerations (eg., cost, fuel consumption, noise) the engine is often selected to have just enough power to drive the expected loads with minimal overhead power. In some situations outside the expected load envelope, the engine can get bogged down. This can, for example, cause a cutting blade to move slower than desired, cause the engine to stall, etc.

[0016] In embodiments described below, a work machine is described that can make automatic adjustments to a traction unit when the engine load from other components (eg., PTO, hydraulics) exceeds a limit. This control scheme can automatically limit a movement speed of the traction unit, reducing the share of engine power being sent to the traction unit and allowing other engine-driven devices to operate as designed. For purposes of this disclosure, the work machine is illustrated as a grounds maintenance platform suitable for mowing and other turf care operations. It will be understood, however, that the concepts described herein may be applicable to a wide variety of work functions and work vehicles.

[0017] In FIG. 1, a side view shows a work vehicle 100 configured as a ride-on grounds maintenance vehicle according to an example embodiment. The work vehicle 100 includes an internal combustion engine 102, e g., a gasoline or diesel engine. A traction unit 104 is driven by the internal combustion engine 102, both being coupled to a vehicle frame 105. In this example, the traction unit includes rear wheels 106, front wheels 107, and a drivetrain (not shown). The drivetrain may include hydraulic motors that drive one or more wheels 106, 107. In other embodiments, a driveshaft and differential may drive the one or more wheels 106, 107 to the engine 102, or some other coupling mechanism may be used (e g., generator and electric motors).

[0018] The work vehicle 100 is a ride-on vehicle, and therefore includes an operator support structure (e.g., seat 108) and controls 109. In this example, the seat 108 and controls 109 are centrally located in a longitudinal direction 110. A work implement 112 is located on a forward section 113 of the work vehicle 100. The work implement 112 may be variously referred to herein and elsewhere as an attachment, accessory, tool, peripheral. The work implement may also be referred to in terms of the work function of the implement, e.g., mower, plow, sweeper, etc.

[0019] The forward section 113 generally corresponds to a leading edge of the work vehicle 100 when it is moving in a forward direction. The forward direction is defined, for example, by the forward view of the operator while seated. A hopper 114 (also referred to as a bin, container, storage unit, etc.) is located at a rearward section 115 of the work vehicle 100, which is opposite the forward section 113 in the longitudinal direction 110. Generally, the hopper 114 collects and stores debris (e.g., grass clippings, leaves, dirt, branches, garbage) generated and / or propelled by the work implement 112.

[0020] Between the work implement 112 and the hopper 114 is a debris collection unit, which is shown in greater detail in FIGS. 2-4. In some embodiments, the work implement 112 may generate its own airflow to propel debris at least partially towards the hopper 114, e.g., via rotary mower blades, sweeper brush, etc. To accommodate other attachments that generate little or no airflow, the work vehicle 100 will include a source of forced air flow (e.g., fan, impeller, turbine) that causes or assists debris flow through a ducting system that provides a closed airflow path between the work implement 112 and the hopper 114.

[0021] In FIG. 2, a cross sectional view shows the work vehicle 100 of FIG. 1. The cross section is taken along a longitudinally-extending centerline of the work vehicle. For clarity, the internal combustion engine 102 is removed from FIG. 2. As indicated by arrows 202, 203, a debris collection unit 200 provides a debris-moving, airflow path between the work implement 112 and the hopper 114. The debris collection unit 200 includes a fan 204 and ducts 205, 206 configured to collect debris from a work region. Inlet duct 205 forms an airflow path between a fan housing 207 and the work implement 112. Outlet duct 206 forms an airflow path between the fan housing 207 and the hopper 114. The debris collection unit 200 further includes a fan motor 208 that drives the fan 204. The fan motor 208 is powered by the internal combustion engine 102, e g., via a mechanical coupling (e g., belt, shaft), hydraulic pump, electric generator, or the like.

[0022] The work vehicle includes a controller 210 coupled (e g., electrically coupled) to the traction unit 104 and the fan motor 208. For example, the controller 210 is operable to control aspects of the traction unit 104, such as setting and measuring current speed, detecting wheel slip, etc. The controller 210 can gather data from other sensors that affect the performance traction unit 104, such as measuring engine state (e g., engine speed, fuel flow), vehicle state (e g., longitudinal and lateral tilt), and the like. The controller 210 controls the fan motor 208, e g., set inputs that control speed and power of the fan 204, and measures at least a rotational speed of the fan motor 208. By measuring fan motor speed as well as an input to the fan motor 208 (e g., a proportional relief valve setting that controls the amount of hydraulic fluid fed to the motor), the controller 210 can detect a load on the fan motor 208, as well as estimate the amount of load. In other embodiments, a fluid pressure and / or flow sensor can be used to directly measure the hydraulic motor inputs, which can be mapped to fan motor load.

[0023] In various embodiments, the controller 210 is operable to measure a speed of the fan motor 208 while the work vehicle 100 is being moved by the traction unit 104 and the debris collection unit 200 is collecting debris. In response to detecting debris loading on the fan motor, an input to the fan motor 208 is increased by the controller 210 to compensate for the debris loading. This input may result an increase in hydraulic flow, for example. In response to the increase of the input to the fan motor 208 the controller 210 restricts a maximum motive speed of the traction unit 104. In this way, the controller 210 can prevent overloading the engine 102 during periods of high debris load or other situations (eg., branches stuck in the flow path) that require extra effort on the part of the fan motor 208 to deal with.

[0024] The debris loading of the fan may be detected as the speed of the fan motor falling below a speed threshold and / or load on the fan motor increasing past a load threshold. Note that in some cases load is indirectly detected based on a control input to the motor together with fan speed, e g., a setting of a hydraulic input to the fan motor. For example, if fan motor input X is expected to result in fan speed Y under normal loading, then measuring fan speed Yi « Y for input X is indicative of significant loading and may trigger either or both a speed threshold and load threshold indicator.

[0025] While not shown in FIG. 2, the work vehicle 100 includes a PTO unit that drives the work implement 112. The PTO unit is driven by the internal combustion engine 102 independently of the fan motor 208, e.g., they may be deactivated and activated independently, they may run at different speeds, etc. The PTO unit includes shaft or other mechanical drive element that extends towards the forward section 113 of the work vehicle 100 to power the work implement 112. The PTO may load the engine 102 significantly, and the controller may be further operable to, regardless of whether or not the input to the fan motor 208 is increased, restrict the maximum speed of the traction unit 104 in response to an increase of load on the PTO unit. The restriction of maximum traction speed may be extended to any source of mechanical load on the engine 102 that can be detected by the controller 210.

[0026] In FIGS. 3, 4A and 4B, respective side and front views show additional details of the debris collection unit 200 according to an example embodiment. The ducts 205, 206 and fan housing 207 are centrally located in a lateral direction in the frame 105 of the work vehicle 100. The ducts 205, 206 may include multiple separable parts, e.g., for ease of assembly and maintenance. The inlet duct 205 is coupled to a low pressure side of the fan 204 via a mounting plate 300. As seen in FIGS. 4A and 4B, the mounting plate 300 seals off the front of the fan housing 207 except for inlet orifice 400 to which the inlet duct 205 attaches.

[0027] In FIG. 4A, the inlet orifice 400 is located off-center from the fan 204, as indicated by lateral offset 402 from fan rotational axis 404. This off-center location can increase fan efficiency by reducing the amount of debris rotating within the fan housing 207. In the view of FIG. 4A, the fan 204 rotates in a counterclockwise direction, such that a large portion of debris entering through the inlet orifice 400 will be directed upwards out of the outlet duct 206. This is in contrast to a more common arrangement where the orifice and fan are centrally aligned, in which case the debris will be more evenly distributed throughout the fan housing as it moves from the inlet to the outlet. By reducing the amount of debris rotating in the fan housing during steady state operation, the load on the fan motor 208 can be reduced and power efficiency increased.

[0028] In some embodiments, a different orifice to fan alignment may be desirable. As shown in FIG. 4B, other inlet orifice locations relative to the fan rotational axis 404 may be possible, as indicated by circles 410. Such alternate locations may be user selectable, e.g., by changing out different mounting plates, by employing a slideable orifice plate between the mounting plate 300 and fan housing 207. Selecting different fan-to-orifice alignments allows altering fan characteristics based on conditions of use, e.g., type of work implement 112, type of debris being collected, etc.

[0029] In FIG. 5, a flowchart shows an example of how a controller performs debris collection load compensation according to an example embodiment. Block 500 represents an entry point into an infinite control loop that varies some aspects of traction control. Block 501 determines whether the fan speed is low, e.g., via a signal from an encoder or other speed sensor. Note that the determination of “low” fan speed may inherently depend on what the expected speed should be (e.g., based on an input to the fan motor). The expected speed may vary, e.g., based on a current operating mode.

[0030] At block 502, the fan speed is low, and so fan motor input is boosted, e.g., by increasing hydraulic flow, electric current flow, etc., and the traction speed is limited. This may result in an excessive load on the engine, as indicated at block 503. Note that the excessive load may be due to multiple contributors that by themselves would not present an excessive load. For example, when cutting especially long and thick grass, but the work implement and fan will be highly loaded. This could trigger block 503 returning ‘yes,’ even if their individual load contributions would not do so.

[0031] If the load is excessive (block 503 returns ‘yes’), the maximum speed of the traction unit is limited, e g., reduced from a default maximum speed. As with the fan speed, the reduced and default maximum tractions speed may be dependent on a current operating mode of the work vehicle. If the debris load is not excessive (block 503 returns ‘no’), the limit on maximum traction speed is removed at block 504, and this block 504 would do nothing if there was already not a debris-loading-based limit imposed.

[0032] In FIG. 5, the traction speed reduction at block 506 may occur even if fan speed is acceptable (block 501 returns ‘no’). Block 505 checks for other sources of engine load, and can also perform the operations in blocks 504 and 506 as appropriate. Note that other operations may be performed that are not shown here, e.g., to remove boost from the fan motor if its speed is no longer low. Other operations may be performed without departing from the scope of this example, and illustrated operations may be performed in different orders than shown.

[0033] In FIG. 6, a diagram shows machine modes which could affect operation according to an example embodiment. The blocks in FIG. 6 represent user-selected and / or automatic mode settings related to work implement settings (attachment settings block 600). Blocks 601-605 represent an example of different attachment functions and / or types that may be fitted to the work vehicle. The attachment settings indicated by the blocks 601-605 may be manually selected in a user interface (e g., digital display) and / or be automatically detected, e g., by a sensor that can read identification data from a currently attached work implement.

[0034] In FIGS. 7-11, block diagrams illustrate automatic load speed settings / modes for different attachment blocks 601-605 of FIG. 6. For purposes of explanation, FIG. 7 will be described in greater detail. This will facilitate an understanding of other settings shown in FIGS. 8-11, which may not all be addressed directly. Generally, the indicators E x,, I_x, and T_x in FIGS. 7-11 refer to respective engine, fan (impeller), and traction speeds, e.g., E HIGH refers to a high engine speed. For purposes of these examples, the engine speeds can range between 2500 and 3200 RPM, the impeller speeds can range between 1800 and 3200 RPM, and traction speeds can range between 3 and 10 miles per hour (MPH). These numerical values are presented for purposes of illustration and not limitation and may vary based on, among other things, type of engine (e g., gasoline vs. diesel), impeller size and flow capacity, traction configuration (e g., wheel size, wheeled vs. tracked).

[0035] In FIG. 7, the rotary mower attachment block 601 is selected, which presents options for additional mode settings as indicated by blocks 701-704. The blocks 701-704 (or an equivalent) can be presented via a user interface to facilitate user selection of current turf conditions. As indicated by table 705, different maximum forward speeds may be imposed (last column) based on state values shown in the first three columns of table 705, which define, in order, a maximum engine speed, default speed of the fan, and an impeller boost setting. The AUTO boost setting will increase the fan speed (e g., to IHIGH) due to fan loading above a threshold (e g., detected by drop in fan speed), and will revert to the default speed once fan loading is below the threshold (e g., detected by a sudden increase in fan speed). The ON boost setting will set the fan to the I HIGH boost speed regardless of measured fan speed.

[0036] In one embodiment, if boost is applied to the fan motor, its input speed may be changed from a default speed set point indicated in the second column to a predetermined value, e g., 3,000 revolutions per minute (RPM). Note that in the mulch mode (block 704), the work vehicle will not collect clippings, therefore the fan motor will be shut off. As a result, the middle two columns of table 705 are empty, indicating the boost function is not relevant to this state. Because the mulching mode would still involve driving the rotary mower blades, a maximum forward speed may still be enforced under heavy load, as indicated by the last column of the last row of table 705. This is in contrast to the last column of FIG. 9, in which the plow does not draw from the PTO, and so no maximum speed is enforced based on at least these two criteria.

[0037] In examples shown in FIGS. 7-11, the boost mode is triggered by determining an increased amount of debris load on the fan motor and increasing an input to the motor in response, which results in restricting the maximum speed of the traction unit. The boost may be triggered by measuring the target / default speed of the fan dropping below a speed threshold. This speed threshold may be a fixed amount (e g., 200 RPM) or a proportional amount (eg., 10% of target RPM). Since the relation between fan speed and applied load to the fan motor may not be linear, other thresholds may be used that reference the detected fan motor load as described elsewhere.

[0038] In FIG 12, a block diagram shows a work vehicle traction and work implement control system 1200 according to an example embodiment. A fan speed sensor 1202 is coupled one or both of the fan 204 and fan motor 208 to provide a measured speed signal 1203 to the controller. The fan speed sensor 1202 may include any combination of an optical sensor, magnetic sensor, audio sensor, etc.

[0039] The controller 210 inputs a target speed signal 1201 to the fan motor 208 to set the target speed. The target speed signal 1201 need not be an explicit speed value. For example, the signal 1201 may be an integer value (e.g., 0-255) that is sent to control an opening amount of a valve (not shown) that provides hydraulic fluid to the fan motor 208. The controller 210 may use an internal lookup table or function that maps the target fan RPM (e g., a map key or table index) to valve settings (the map or table value). The map or function that relates fan RPM to valve settings can be derived by testing, e g., setting the hydraulic valve input values and measuring unloaded fan speed. The target speed 1201 can be compared to the measured speed 1203 to determine debris loading. For example, if target speed 1201 is 2,000 RPM but measured speed is 1,200 RPM, then some level of loading can be assumed and estimated. The relation between RPM change and debris loading can also be found experimentally, e g., by, using a constant fan motor input, mapping changes between unloaded fan speed and loaded fan speed over various feed volumes of test debris.

[0040] In response to a threshold level of debris loading, the controller can send a maximum forward speed setting command 1205 to a traction controller 1204. This may be in response to the fan motor being sent into a boost mode, or may be triggered by some threshold level of fan input increase, e g., an additional >X% of nominal fan motor driving power is required to maintain a desired fan speed. The traction controller 1204 can be a separate processor (e g., transmission control module) or be part of controller 210. The speed limits described in the command 1205 can be used in combination with other commands (eg., user accelerator input) to set the forward speed 1207 of the traction unit 104.

[0041] As noted above, a mode selection 1208, e g., via a user interface, may be considered when determining thresholds for triggering and / or setting a value of the maximum forward speed setting command 1205. Similarly, signals from other sensors 1210 (e g., PTO speed, hydraulic pump pressure and flow rate, engine speed, hydraulic fluid temperature) can be used to detect other sources of loading that can also or instead be used in triggering and / or setting a value of the maximum forward speed setting command 1205.

[0042] The controller 210 may include electronic components to send and receive the illustrated signals, e g. filters, preamplifiers, analog-to-digital converters (ADC), digital-to-analog converters (DAC), etc. The signals may be analog signals (e.g., line voltages) and / or digital messages sent over a communications bus, e g., controller area network (CAN), inter-integrated circuit (I2C), etc. The electronic controller components may be combined onto a system on a chip (SoC) that generally governs operations of the grounds maintenance vehicle by executing software or firmware instructions.

[0043] In FIG. 13, a flowchart shows a controller-implemented method of regulating operation of a work vehicle according to an example embodiment. The method involves moving 1300 the work vehicle along a work region via a traction unit, wherein the traction unit is driven by an internal combustion engine. While the work vehicle is moving, debris is collected 1301 via a debris collection unit that includes: a fan; a duct; and a fan motor that drives the fan. The fan motor is powered by the internal combustion engine. In response to detecting debris loading of the fan, an input to the fan motor is increased 1302 to compensate thereto. In response to the increase of the input to the fan motor, a maximum speed of the traction unit is restricted 1303.

[0044] While the present disclosure is not so limited, an appreciation of various aspects of the disclosure will be gamed through a discussion of the specific illustrative aspects provided below. Various modifications of the illustrative aspects, as well as additional aspects of the disclosure, will become apparent herein.

[0045] Example 1 is a work vehicle, comprising: an internal combustion engine; a traction unit driven by the internal combustion engine; a debris collection unit comprising a fan and duct configured to collect debris from a work region, the debris collection unit further comprising a fan motor that drives the fan, the fan motor being powered by the internal combustion engine; and a controller coupled to the traction unit and the fan motor, the controller operable to perform: measuring a speed of the fan motor while the work vehicle is being moved by the traction unit and the debris collection unit is collecting the debris; in response to detecting debris loading on the fan motor, increasing an input to the fan motor to compensate thereto; and in response to the increase of the input to the fan motor, restricting a maximum speed of the traction unit.

[0046] Example 2 includes the work vehicle of example 1, wherein the debris loading of the fan is detected as the speed of the fan motor falling below a speed threshold. Example 3 includes the work vehicle of example 1 or 2, wherein the debris loading of the fan is detected as a load on the fan motor increasing past a load threshold. Example 4 includes the work vehicle of example 3, wherein the load on the fan motor is detected by a combination of the speed of the fan motor and a setting of a hydraulic input to the fan motor.

[0047] Example 5 includes the work vehicle of any preceding example, further comprising: a power takeoff unit driven by the internal combustion engine; and a work implement coupled to and driven by the power takeoff unit, wherein the debris is provided to the debris collection unit via the work implement. Example 6 includes the work vehicle of example 5, wherein the work implement comprises a rotary mower attachment or a flail mower attachment. Example 7 includes the work vehicle of example 5 or 6, wherein the controller is further operable to, regardless of whether or not the input to the fan motor is increased, restrict the maximum speed of the traction unit in response to an increase of a load on the power takeoff unit. Example 8 includes the work vehicle of example 5, 6, or 7, wherein the power takeoff unit operates independently of the fan motor.

[0048] Example 9 includes the work vehicle of any preceding example, further comprising a user interface that facilitates user selection of current turf conditions, wherein a default speed of the fan motor is changed depending on a selected one of the current turf conditions. Example 10 includes the work vehicle of any preceding example, wherein the fan motor comprises a hydraulic motor that is hydraulically driven by the internal combustion engine, and wherein increasing the input to the fan motor comprises increasing hydraulic fluid flow from a hydraulic pump to the fan motor. Example 11 includes the work vehicle of example 10, wherein increasing the hydraulic fluid flow from the hydraulic pump to the fan motor comprises sending a signal to a proportional relief valve that controls the hydraulic fluid flow.

[0049] Example 12 includes the work vehicle of any preceding example, wherein the duct is centrally located in a lateral direction in a frame of the work vehicle. Example 13 includes the work vehicle of example 12, wherein the debris is collected from a forward section of the work vehicle, and wherein the duct feeds into a hopper located at a rearward section of the work vehicle.

[0050] Example 14 is a controller-implemented method of regulating operation of a work vehicle, comprising: moving the work vehicle along a work region via a traction unit, wherein the traction unit is driven by an internal combustion engine; while the work vehicle is moving, collecting debris via a debris collection unit comprising: a fan; a duct; and a fan motor that drives the fan, the fan motor being powered by the internal combustion engine; in response to detecting debris loading of the fan, increasing an input to the fan motor to compensate thereto; and in response to the increase of the input to the fan motor, restricting a maximum speed of the traction unit.

[0051] Example 15 includes the method of example 14, wherein the debris loading of the fan is detected as a speed of the fan motor falling below a speed threshold. Example 16 includes the method of example 14 or 15, wherein the debris loading of the fan is detected as a load on the fan motor increasing past a load threshold.

[0052] Example 17 includes the method of any preceding method example, further comprising, regardless of whether or not the input to the fan motor is increased, restricting the maximum speed of the traction unit in response to an increase of a load on a power takeoff unit that drives a work implement. Example 18 includes the method of any preceding method example, further comprising receiving a user selection of current turf conditions, wherein a default speed of the fan motor is changed depending on a selected one of the current turf conditions. Example 19 includes the method of any preceding method example, wherein the fan motor comprises a hydraulic motor that is hydraulically driven by the internal combustion engine via a hydraulic pump, and wherein increasing the input to the fan motor comprises increasing hydraulic fluid flow from the hydraulic pump to the fan motor. Example 20 includes the method of example 19, wherein increasing the hydraulic fluid flow from the hydraulic pump to the fan motor comprises sending a signal to a proportional relief valve that controls the hydraulic fluid flow.

[0053] It is noted that the terms “have,” “include,” “comprises,” and variations thereof, do not have a limiting meaning, and are used in their open-ended sense to generally mean “including, but not limited to,” where the terms appear in the accompanying description and claims. Further, “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably herein. Moreover, relative terms such as ’’left,” “right,” “front,” “fore,” “forward,” “rear,” “aft,” “rearward,” “top,” “bottom,” “side,” “upper,” “lower,” “above,” “below,” “horizontal,” “vertical,” and the like may be used herein and, if so, are from the perspective shown in the particular figure, or while the machine is in an operating configuration. These terms are used only to simplify the description, however, and not to limit the interpretation of any embodiment described. As used herein, the terms “determine” and “estimate" may be used interchangeably depending on the particular context of their use, for example, to determine or estimate a position or pose of a vehicle, boundary, obstacle, etc.

[0054] Further, it is understood that the description of any particular element as being connected to or coupled to another element can be directly connected or coupled, or indirectly coupled / connected via intervening elements.

[0055] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified in all instances by the term “about,” e g., within ±10%. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein. The use of numerical ranges by endpoints includes all numbers within that range (e g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within that range.

[0056] The various embodiments described above may be implemented using circuitry, firmware, and / or software modules that interact to provide particular results. One of skill in the arts can readily implement such described functionality, either at a modular level or as a whole, using knowledge generally known in the art. For example, the flowcharts and control diagrams illustrated herein may be used to create computer-readable instructions / code for execution by a processor. Such instructions may be stored on a non- transitory computer-readable medium and transferred to the processor for execution as is known in the art. The structures and procedures shown above are only a representative example of embodiments that can be used to provide the functions described hereinabove.

[0057] Note that any components described herein using terms such as “processor,” “controller,” “logic circuit,” “CPU,” or the like may be implemented using a plurality of discrete units operating together. For example, a processer that performs a series of steps or operations may be construed as two or more processors operating cooperatively to perform the steps. Similarly, other processing hardware such as memory and input-output may perform the described functions with multiple discrete units operating cooperatively or being coordinated by another unit, eg., by a central processor or processors.

[0058] The foregoing description of the example embodiments has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the embodiments to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. Any or all features of the disclosed embodiments can be applied individually or in any combination and are not meant to be limiting, but purely illustrative. It is intended that the scope of the invention be limited not with this detailed description, but rather determined by the claims appended hereto.

Claims

1. A work vehicle, comprising:an internal combustion engine;a traction unit driven by the internal combustion engine;a debris collection unit comprising a fan and duct configured to collect debris from a work region, the debris collection unit further comprising a fan motor that drives the fan, the fan motor being powered by the internal combustion engine; anda controller coupled to the traction unit and the fan motor, the controller operable to perform:measuring a speed of the fan motor while the work vehicle is being moved by the traction unit and the debris collection unit is collecting the debris;in response to detecting debris loading on the fan motor, increasing an input to the fan motor to compensate thereto; andin response to the increase of the input to the fan motor, restricting a maximum speed of the traction unit.

2. The work vehicle of claim 1, wherein the debris loading of the fan is detected as the speed of the fan motor falling below a speed threshold.

3. The work vehicle of either claim 1 or 2, wherein the debris loading of the fan is detected as a load on the fan motor increasing past a load threshold.

4. The work vehicle of claim 3, wherein the load on the fan motor is detected by a combination of the speed of the fan motor and a setting of a hydraulic input to the fan motor5. The work vehicle of any one of claims 1 to 4, further comprising:a power takeoff unit driven by the internal combustion engine; anda work implement coupled to and driven by the power takeoff unit, wherein the debris is provided to the debris collection unit via the work implement.

166. The work vehicle of claim 5, wherein the work implement comprises a rotary mower attachment or a flail mower attachment.

7. The work vehicle of either claim 5 or 6, wherein the controller is further operable to, regardless of whether or not the input to the fan motor is increased, restrict the maximum speed of the traction unit in response to an increase of a load on the power takeoff unit.

8. The work vehicle of any one of claims 5 to 7, wherein the power takeoff unit operates independently of the fan motor.

9. The work vehicle of any one of claims 1 to 8, further comprising a user interface that facilitates user selection of current turf conditions, wherein a default speed of the fan motor is changed depending on a selected one of the current turf conditions.

10. The work vehicle of any one of claims 1 to 9, wherein the fan motor comprises ahydraulic motor that is hydraulically driven by the internal combustion engine, and wherein increasing the input to the fan motor comprises increasing hydraulic fluid flow from a hydraulic pump to the fan motor.

11. The work vehicle of claim 10, wherein increasing the hydraulic fluid flow from the hydraulic pump to the fan motor comprises sending a signal to a proportional relief valve that controls the hydraulic fluid flow.

12. The work vehicle of any one of claims 1 to 11, wherein the duct is centrally located in a lateral direction in a frame of the work vehicle.

13. The work vehicle of claim 12, wherein the debris is collected from a forward section of the work vehicle, and wherein the duct feeds into a hopper located at a rearward section of the work vehicle.

14. A controller-implemented method of regulating operation of a work vehicle, comprising:moving the work vehicle along a work region via a traction unit, wherein the traction unit is driven by an internal combustion engine;while the work vehicle is moving, collecting debris via a debris collection unit comprising: a fan; a duct; and a fan motor that drives the fan, the fan motor being powered by the internal combustion engine;in response to detecting debris loading of the fan, increasing an input to the fan motor to compensate thereto; andin response to the increase of the input to the fan motor, restricting a maximum speed of the traction unit.

15. The method of claim 14, wherein the debris loading of the fan is detected as a speed of the fan motor falling below a speed threshold.

16. The method of claim either 14 or 15, wherein the debris loading of the fan isdetected as a load on the fan motor increasing past a load threshold.

17. The method of claim any one of claims 14 to 16, further comprising, regardless of whether or not the input to the fan motor is increased, restricting the maximum speed of the traction unit in response to an increase of a load on a power takeoff unit that drives a work implement.

18. The method of any one of claims 14 to 17, further comprising receiving a user selection of current turf conditions, wherein a default speed of the fan motor is changed depending on a selected one of the current turf conditions.

19. The method of any one of claims 14 to 18, wherein the fan motor comprises a hydraulic motor that is hydraulically driven by the internal combustion engine via a hydraulic pump, and wherein increasing the input to the fan motor comprises increasing hydraulic fluid flow from the hydraulic pump to the fan motor.

20. The method of claim 19, wherein increasing the hydraulic fluid flow from the hydraulic pump to the fan motor comprises sending a signal to a proportional relief valve that controls the hydraulic fluid flow.

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