Method for supporting a charging process

Abstract

Method for assisting a loading process, in which a front loader (16) is provided on a commercial vehicle (14), which front loader comprises a loading tool (18) for receiving a load (20) and a hydraulically adjustable loader linkage (24) for pivoting and for raising or lowering the loading tool (18), wherein a control unit (52) monitors, during the execution of a loading process, whether a travel state indicating a current or intended forward travel of the commercial vehicle (14) leads to a potential overload state of a travel drive (40) provided for carrying out the forward travel, in order to automatically bring the commercial vehicle (14) into a drive-neutral standstill and to hold it there in a loading assistance mode by intervening in a drive and / or brake management system (64).

Description

[0001] The invention relates to a method for supporting a loading process, in which a front loader arranged on a commercial vehicle is provided, which comprises a loading tool for receiving a load and a hydraulically adjustable loader linkage for pivoting and for raising or lowering the loading tool.

[0002] Such front loaders are used to load, among other things, loose cargo using a loading tool, particularly designed as a shovel, which is located at one free end of the front loader. The loading tool or shovel can be adjusted in terms of its height relative to the ground and its inclination about a pivot axis running transversely to the longitudinal extent of the commercial vehicle by actuating hydraulic adjusting devices that are part of the loader linkage. This allows the shovel to be immersed in a specific load for the purpose of filling the shovel. The front loader is attached to the front of an agricultural tractor, for example, as a removable attachment, but it can also be designed as a shovel excavator, telescopic loader, or other similar loading vehicle from the construction or agricultural sectors.The cargo is primarily loose goods such as grain, corn, gravel, sand, earth or the like.

[0003] Picking up the load using the loading attachment places increased demands on the operator due to the required coordination between controlling the commercial vehicle's travel movement, i.e., maneuvering the commercial vehicle, and the loading movement of the loading attachment, which is carried out by controlling the hydraulically adjustable loader linkage. Therefore, depending on the type of load, less experienced operators may find that the resistance encountered when the loading attachment moves into or plunges into the load exceeds the performance of an internal combustion engine used as a drive, leading to the engine stalling in the worst case scenario.

[0004] In view of this, it is the object of the present invention to provide a method of the type mentioned at the outset which takes into account the performance of an internal combustion engine used as a drive when carrying out a loading process with a front loader.

[0005] This object is achieved by a method for supporting a charging process having the features of patent claim 1.

[0006] In the method provided for assisting a loading process, a front loader is provided on a commercial vehicle, which front loader comprises a loading tool for receiving a load and a hydraulically adjustable loader linkage for pivoting and raising or lowering the loading tool, wherein a control unit monitors during the execution of a loading process whether a driving state indicating a current or intended forward travel of the commercial vehicle leads to a potential overload state of a drive provided for carrying out the forward travel, in order to automatically bring the commercial vehicle into a drive-neutral standstill and hold it there in a loading assistance mode by intervening in a drive and / or brake management system.

[0007] This makes it possible to carry out a loading operation with a front loader without the possibility that the resistance encountered when the loading tool is driven into or immersed in the load will exceed the performance of an internal combustion engine used as a drive.

[0008] To achieve drive-neutral standstill, the control unit can be used to control the drive and / or brake management system in such a way that the drive connection between the drive system and the driven wheels of the commercial vehicle is interrupted while simultaneously actuating the associated wheel brakes. If the drive system includes a vehicle transmission in the form of a manual or CVT transmission, the drive connection is typically interrupted by disengaging a drive clutch. However, if an IVT transmission is used, the drive clutch is omitted; in this case, drive-neutral standstill is achieved by selecting the "infinite" gear ratio.

[0009] Generally speaking, drive-neutral standstill is characterized by the fact that the driven wheels of the commercial vehicle are free of drive torque. The application of the wheel brakes ensures that the commercial vehicle cannot roll away in this state.

[0010] It is possible for the control unit to detect a driving condition indicating current or intended forward movement of the commercial vehicle by observing characteristic signs in the form of driving-related driver actions, such as the actuation of the accelerator pedal or drive lever with a forward gear engaged, or by evaluating the direction of rotation of the commercial vehicle's wheels. The relevant information can be captured by sensors and made available to the control unit, for example, via a CAN data bus.

[0011] The front loader is used to load, among other things, loose cargo using a loading tool designed as a shovel or similar, which is located at one free end of the front loader. The loading tool can be adjusted in terms of its height relative to the ground and its inclination around a pivot axis running transversely to the longitudinal extent of the commercial vehicle by actuating hydraulic adjusting devices, which are designed as hydraulic cylinders and are part of the loader linkage. This enables the loading tool to be immersed in a specific load for the purpose of filling the loading tool. The front loader is attached to the front of an agricultural tractor, for example, as a removable attachment, but it can also be designed as a shovel excavator, telescopic loader, or other similar loading vehicle from the construction or agricultural sectors.The cargo is primarily loose goods such as grain, corn, gravel, sand, earth or the like.

[0012] Advantageous embodiments of the method according to the invention emerge from the subclaims.

[0013] Preferably, the control unit concludes that the traction drive is potentially overloaded if the resistance encountered by the loading tool when picking up the load exceeds an overload-specific limit. If the traction drive includes an internal combustion engine, the overload-specific limit is selected, in particular, based on an engine characteristic curve assumed to be known, typically such that the limit is characteristic of an impending stall of the internal combustion engine. The latter occurs when the engine speed expected based on the engine characteristic curve and the injected fuel quantity is not reached or falls below the maximum.

[0014] The resistance encountered by the loading tool when picking up the load can be derived by the control unit by evaluating sensor-detected pressure conditions in hydraulic cylinders intended for adjusting the loader linkage and / or actuation torques detected by sensors on the loader linkage, each dependent on the current position of the loader linkage and thus the resulting leverage ratios. The sensor-detected actuation torques can be measured using strain gauges placed at suitable points on the loader linkage. Additionally or alternatively, it is conceivable to evaluate axle load changes occurring in this context on a front axle of the commercial vehicle, in particular by observing a resulting change in tire pressure in the front wheels.

[0015] Furthermore, it can be provided that in loading assistance mode, the control unit prevents the loading process from being carried out by intervening in a hydraulic control system, at least until the drive-neutral standstill is detected. The hydraulic control system can then be released in such a way that the driver can continue the loading process. In addition, there is the option of canceling the drive-neutral standstill as soon as the control unit detects that a potential overload condition of the travel drive is no longer to be expected. In this case, forward travel can be resumed in order to immerse the loading tool further into the load, with the loading assistance mode still active. If a potential overload condition of the travel drive is detected again, the process described above starts again from the beginning.This repetitive process results in the load being picked up piece by piece using the loading tool and can therefore also be described as "ratchet digging".

[0016] It is also conceivable that, in charging assistance mode, a user interface controlled by the control unit could output driver information indicating a potential overload condition of the drive system. The driver information output would be canceled or modified when the drive-neutral standstill is detected. The driver information could, for example, be displayed as a traffic light on a user interface display, which changes from red to green and vice versa when the functional restriction is removed. This type of information presentation is particularly easy for the driver to understand intuitively.

[0017] The method according to the invention is explained in more detail below with reference to the accompanying drawings. They show: Fig. 1 shows an embodiment of the method according to the invention for supporting a loading process with a front loader, illustrated as a flow chart, and Fig. 2 shows a schematically illustrated arrangement for carrying out the method according to the invention.

[0018] Fig. 1 shows an embodiment of the method according to the invention for supporting a loading process with a front loader, shown as a flow chart, which is described below with reference to the arrangement provided for its implementation according to Fig. 2 should be described.

[0019] Starting from Fig. 2 the arrangement 10 is a component of a commercial vehicle 14 designed as an agricultural tractor 12 with a front loader 16 arranged thereon, wherein the front loader 16 is attached in the front area of ​​the agricultural tractor 12 as a removable additional device and comprises a loading tool 18 for receiving a load 20 from a load supply 22 and a hydraulically adjustable loader linkage 24 for pivoting and for raising or lowering the loading tool 18.

[0020] More precisely, the front loader 16 serves, among other things, to load loose cargo 20, for which the loading tool 18 is designed as a bucket 30 located at a free end 26 of the front loader 16 or a loader arm 28. The bucket 30 can be adjusted in its height relative to the ground 38 and its inclination about a pivot axis running transversely to the longitudinal extent of the agricultural tractor 12 by actuating hydraulic adjusting devices 32 in the form of associated hydraulic cylinders 34, 36, which are part of the loader linkage 24, so that a targeted immersion of the bucket 30 into the cargo supply 22 for the purpose of filling the bucket 30 is possible. The cargo 20 is, for example, loose goods such as grain, corn, gravel, sand, earth, or the like.

[0021] Furthermore, an internal combustion engine 42 used as the drive 40 is connected via a vehicle transmission 44 to driven front and / or rear wheels 46, 48 of the agricultural tractor 12. The internal combustion engine 42 also serves to operate a hydraulic system 50 of the agricultural tractor 12, which, among other things, supplies the hydraulic actuating devices 32 of the front loader 16 with hydraulic energy.

[0022] As also in Fig. 2 As can be seen, the arrangement 10 comprises a microprocessor-controlled control unit 52 which communicates via a CAN data bus 54 with an internal memory unit 56 and a user interface 60 designed as a touch-sensitive display 58.

[0023] Furthermore, a hydraulic control 62 for actuating the hydraulic actuating devices 32 of the front loader 16 as well as a drive and / or brake management system 64 are provided, which allows a targeted actuation of associated wheel brake devices 66 of the agricultural tractor 12 as well as communication with a device for operating the internal combustion engine 42 or

[0024] The engine or transmission control unit 68, 70 provided for the vehicle transmission 44. The transmission control unit 70 enables the control unit 52, in the event that the agricultural tractor 12 is equipped with a CVT or manual transmission, to interrupt the drive connection to the driven front and / or rear wheels 46, 48 by opening a drive clutch 72.

[0025] Feedback regarding the operating state of the loader linkage 24 to the control unit 52 is provided by means of several Fig. 2 Sensors combined in a functional block 74, which serve to record the pressure conditions in the hydraulic cylinders 34, 36 provided for adjusting the loader linkage 24 or of the actuating torques occurring on the loader linkage 24, each depending on its current position.

[0026] According to the Fig. 1According to the flowchart shown, the method performed by the control unit 52 and stored as corresponding program code in the internal memory unit 56 is started in a start step 100 by the operator by calling up a charging assistance mode via the touch-sensitive display 58 of the user interface 60, whereupon in a first main step 102 the control unit 52 checks, based on information provided by the drive and / or brake management system 64, whether a reverse gear is engaged or the wheel brake devices 66 are currently being actuated. If this is the case, the method returns to the beginning via an intermediate step 104 to be executed again.Otherwise, the program continues with a second main step 106, in which the control unit 52 additionally checks whether a driving condition exists that indicates current or intended forward travel of the agricultural tractor 12. This condition is detected by the control unit 52 by observing characteristic signs in the form of drive-related driver actions, such as actuating the accelerator pedal or drive lever with a forward gear engaged, or by evaluating the direction of rotation of the front and / or rear wheels 46, 48 of the agricultural tractor 12. The relevant information is recorded by sensors and made available to the control unit 52 via the CAN data bus 54. If such a driving condition exists, the program continues with a third main step 108, in which the control unit 52 checks whether this could lead to a potential overload condition of the drive 40 provided for forward travel.Otherwise, the method returns to the first main step 102 to be executed again.

[0027] More precisely, in the third main step 108, the control unit 52 concludes that the propulsion drive 40 is potentially overloaded if the resistance to the bucket 30 when picking up the load 20 exceeds an overload-specific limit value. If the propulsion drive 40 comprises an internal combustion engine 42, as is the case here, the overload-specific limit value is selected based on an engine characteristic curve that is assumed to be known and stored in the engine control unit 68, in such a way that the limit value is characteristic of an impending stall of the internal combustion engine 42. The latter is the case if the engine speed expected based on the engine characteristic curve and the injected fuel quantity is not reached or is below the engine speed.

[0028] The resistance of the bucket 30 when picking up the load 20 is derived by the control unit 52 by evaluating the sensor-detected pressure conditions in the hydraulic cylinders 34, 36 provided for adjusting the loader linkage 24 and / or the actuating torques detected by sensors on the loader linkage 24, each depending on the current position of the loader linkage 24 and thus the resulting leverage ratios. The sensor-detected actuating torques are detected using strain gauges (not shown) placed at suitable points on the loader linkage 24. Optionally, the control unit 52 evaluates axle load changes occurring in this context on a front axle of the agricultural tractor 12, in particular also by observing a change in the tire inflation pressure in the front wheels 46 caused thereby.

[0029] If it turns out in the third main step 108 that the overload-specific limit value has been exceeded, the agricultural tractor 12 is brought to a drive-neutral standstill in a fourth main step 110; otherwise, the method continues immediately with the intermediate step 104 to start again from the beginning.

[0030] To achieve drive-neutral standstill, the fourth main step 110 provides that, at the instigation of the control unit 52, the drive and / or brake management system 64 is controlled in such a way that an interruption of the drive connection between the traction drive 40 and the driven front and / or rear wheels 46, 48 of the agricultural tractor 12 occurs by opening the drive clutch 72 by means of the transmission control unit 70 with essentially simultaneous actuation of the wheel brake devices 66 in a fifth main step 112. If the vehicle transmission 44 is an IVT transmission instead of a CVT or manual transmission, the drive clutch 72 is omitted; in this case, the drive-neutral standstill is achieved by selecting the "infinite" gear ratio.

[0031] Generally speaking, drive-neutral standstill is characterized by the fact that the driven front and / or rear wheels 46, 48 of the agricultural tractor 12 are free of drive torque. The actuation of the wheel brake devices 66 ensures that the agricultural tractor 12 cannot roll away in this state.

[0032] Furthermore, it is provided that in loading assistance mode, the control unit 52 prevents the execution of the loading process by intervening in the hydraulic control 62 at least until the drive-neutral standstill is detected. Subsequently, the hydraulic control 62 is released in a sixth main step 114 such that the loading process can be continued by the driver. In addition, the drive-neutral standstill is canceled as soon as the control unit 52 detects that a potential overload condition of the travel drive 40 is no longer to be expected. In this case, forward travel can be resumed in order to further immerse the bucket 30 into the load 20, with the loading assistance mode still active. If a potential overload condition of the travel drive 40 is detected again, the process described above starts again from the beginning.This repetitive process results in the load 20 being picked up piece by piece by means of the shovel 30 and can therefore also be symbolized as "ratchet digging".

[0033] In addition, in charging assistance mode, driver information indicating the potential overload condition of the drive system 40 is output via the user interface 60, which can be controlled by the control unit 52. The output of the driver information is canceled or modified when the drive-neutral standstill is detected. The driver information is output, for example, in the form of a traffic light shown on the display 58 of the user interface 60, which changes from red to green and vice versa when the functional restriction is removed. This type of information presentation is particularly easy for the driver to understand intuitively.

[0034] The process then returns to the beginning via intermediate step 104.

[0035] As a result, the agricultural tractor 12 is automatically brought to a drive-neutral standstill and held there by intervening in the drive and / or brake management system 64. This allows the loading process to be carried out with the front loader 16 without the possibility of the resistance encountered when the bucket 30 moves into or plunges into the load 20 exceeding the performance of the internal combustion engine 42 used as the drive system 40.

[0036] For the sake of completeness, it should be noted that the front loader 16 can also be designed as a shovel excavator, telescopic loader or as another corresponding loading vehicle from the construction or agricultural sector.

Claims

1. A method for assisting a loading process, in which a front loader (16) is provided on a commercial vehicle (14), which front loader comprises a loading tool (18) for receiving a load (20) and a hydraulically adjustable loader linkage (24) for pivoting and for raising or lowering the loading tool (18), wherein a control unit (52) monitors, during the execution of a loading process, whether a travel state indicating a current or intended forward travel of the commercial vehicle (14) leads to a potential overload state of a travel drive (40) provided for carrying out the forward travel, in order to automatically bring the commercial vehicle (14) into a drive-neutral standstill in a loading assistance mode by intervening in a drive and / or brake management system (64) and to hold it there.

2. Method according to claim 1, characterized in thatthe control unit (52) concludes that the travel drive (40) is potentially overloaded if a resistance opposing the loading tool (18) exceeds an overload-specific limit value when the load (20) is picked up.

3. Method according to claim 1 or 2, characterized in that the resistance opposite the loading tool (18) when picking up the load (20) is derived from the control unit (52) by evaluating pressure conditions detected by sensors in hydraulic cylinders (34, 36) provided for adjusting the loader linkage (24) and / or actuating torques detected by sensors on the loader linkage (24), each depending on the current position of the loader linkage (24).

4. Method according to at least one of the preceding claims, characterized in thatIn the loading assistance mode, the control unit (52) prevents the charging process from being carried out by intervening in a hydraulic control system (62) until the drive-neutral standstill is detected.

5. Method according to at least one of the preceding claims, characterized in that in the charging assistance mode, driver information indicating the potential overload state of the drive (40) is output by means of a user interface (60) which can be controlled by the control unit (52), wherein the output of the driver information is cancelled or modified when the drive-neutral standstill is detected.

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