EP3392488A1 - Method for controlling a motor speed of an industrial truck - Google Patents

Abstract

The invention relates to a method for controlling a rotational speed of a drive motor of a commercial vehicle (10) with a drivable charging device (12), wherein a movement drive of the charging device (12) predicts or is detected, and in predicted or detected movement drive of the charging device (12) an increase the engine speed of the drive motor is requested.

Description

The invention relates to a method for controlling a rotational speed of a drive motor of a commercial vehicle.

Agricultural utility vehicles, such as e.g. Tractors, some have a front loader to do specific work such as earthmoving or transport of crop. As far as the working movements of the front loader on the engine power of a drive motor of the commercial vehicle are dependent, this can have an impact on the driving speed of the commercial vehicle.

It is therefore the object of the present invention to propose an improved control of an engine speed for the drive motor of a commercial vehicle.

This object is achieved according to the features of patent claim 1. According to claim 1, a method for controlling a rotational speed of a drive motor of a commercial vehicle with a drivable charging device is provided. In a method step, a movement drive of the charging device is predicted or detected. Here, in particular, a request or execution of a movement drive or a working movement of the charging device is predicted or recognized. If a movement drive or a working movement of the charging device has been predicted or detected, an increase in the engine speed of the drive motor is requested. As a result, the engine power of the drive motor can be increased automatically and thus adapted to specific drive movements of the charging device. Consequently, a vehicle speed of the commercial vehicle, which is usually defined by an accelerator pedal and a brake pedal, is significantly less influenced by the operation of the charging device, which means an increase in the comfort for the driver. In other words, with this comfort function, the vehicle speed can be kept independent of specific driving movements of the charging device. Preferably, as a function of an increase in the engine speed, a vehicle transmission, in particular a transmission ratio, is controlled automatically so that a vehicle speed set by the driver remains constant. As a result, unwanted acceleration or deceleration of the commercial vehicle can be avoided.

The method also supports improved control of the commercial vehicle and the charging device based on the explained control of the engine speed.

Preferably, an operating state of the charging device is used to predict or detect a movement drive of the charging device. In this case, the operating state can be deactivated or activated, i. the charging device is basically switched off (deactivated) or switched on (activated) as a prerequisite for a subsequent movement drive or for a subsequent request or execution of a specific drive movement of the charging device. With an activated operating state can be concluded that with a high probability actually a movement drive of the charging device will take place. In this way, a future movement drive of the charging device can be predicted.

The commercial vehicle is preferably designed as an agricultural vehicle, in particular as a tractor, tractor or the like. The charging device is preferably a working device in the front or rear area of the commercial vehicle. In particular, the charging device has a front loader or consists of a front loader. This has, for example, a movable or pivotable arm on which a working unit or a tool (for example, a blade, a forch, clamping tongs) is mounted.

In a preferred embodiment, the engine speed is an idle speed of the drive motor when the utility vehicle is at a standstill. In this condition, auxiliary and work functions (e.g., PTO operation, auxiliary hydraulic functions) of the commercial vehicle are not active or disabled. In this way, the commercial vehicle can be adapted already at a standstill to an imminent movement drive of the charging device.

Preferably, the increased engine speed is reduced again when a predetermined waiting period (e.g., from the time of increasing the engine speed) has expired and no movement drive is still being executed or at least requested within that waiting period. As a result, the fuel consumption of the drive motor for realizing the comfort function is limited.

Advantageously, a status signal is detected for the prediction or recognition of a movement drive of the charging device, this status signal signaling whether the charging device is in a certain operating state (for example on / off or off / deactivated).

In a preferred embodiment, the loading device is hydraulically driven. This drive takes place by means of a hydraulic drive pump of the commercial vehicle, which with the charger and possibly other hydraulic units (eg brake, steering) is hydraulically connected. In this case, it is favorable first to determine a desired hydraulic flow (eg in liters / minute) as a function of the predicted or detected movement drive of the charging device and then to request an increase in the engine speed as a function of the determined desired hydraulic flow. For example, on the basis of the predicted or detected movement drive of the charging device, first of all a hydraulic volume required for carrying out this drive movement can be determined, and from this the desired hydraulic flow can be determined.

Further preferably, the desired hydraulic flow is determined as a function of one or more detected valve control signals, wherein these valve control signals one or more hydraulic valves for the movement drive of the charging device, in particular a tool of the charging device, are controlled. In this case, for example, a percentage valve opening and / or a time duration of the valve opening can be detected in order to support a determination of the desired hydraulic flow in a technically simple manner.

• eine angeforderte Antriebsbewegung der Ladeeinrichtung,
• eine Antriebscharakteristik der Ladeeinrichtung,
• eine angeforderte Soll-Position der Ladeeinrichtung.

Furthermore, it is favorable if at least one of the following features is taken into account for determining the desired hydraulic flow:

• a requested drive movement of the charging device,
• a drive characteristic of the charging device,
• a requested desired position of the charging device.

The aforementioned features or information can preferably be retrieved at least partially as stored data and thus support the accuracy in determining the desired hydraulic flow. Thus, e.g. The user can determine along which direction, distance or pivot axis the loading device or components thereof (for example, its working unit or tool) are to be moved via an evaluation of specific input commands by the operator. From this information determined then a desired hydraulic flow can be determined.

In the case of a requested desired position of the charging device, this desired position has preferably already been stored in a previous operation in a device for carrying out the method, for example by means of a single position memory button on a control unit. Alternatively, a desired target position may be stored by manually inputting various data to an operator interface, the input data representing the target position. Regardless of the type of storage, the target position may contain different data, such as a Swing angle of a boom or a tool (bucket, forge, clamp, etc.) on the boom, a lifting height of the charger, data of a hydraulic valve, such as a percentage valve opening and / or a period of valve opening to produce a desired hydraulic pressure, a clamping force or a clamping pressure of a tool (eg, forking or clamping tongs) of the charging device. This clamping force is used in particular to support a reliable transport of bales or other goods. A current clamping pressure of this tool is preferably determined or adjusted by means of corresponding sensors. This clamping force can be displayed to a user on a display unit or operator interface. As already mentioned, a user can enter a desired clamping force as data of a desired desired position of the tool or request the already stored clamping force for a new operation again. Thus, a judged as suitable clamping force remains constant and a consistently efficient workflow is guaranteed.

In order to achieve a suitable clamping force, preferably a clamping force can be input and / or displayed directly at an operator interface. Alternatively, a corresponding hydraulic flow rate and associated duration may be entered and / or displayed when the clamping force is adjusted via a hydraulic cylinder. A pressure measurement in this hydraulic cylinder and characteristic lever ratios and / or other geometric variables of the tool can be used to determine a current clamping force. This current clamping force can then be compared with a requested set clamping force. On the basis of the comparison result, a hydraulic flow can then be controlled in such a way that the setpoint clamping force is set.

The consideration of the clamping force or the clamping pressure ensures, for example in the case of silage round bales, that each round bale is subjected to a sufficient clamping force to ensure its safe transport. Differences in size and shape of the bales can be automatically compensated. In addition, excessive bruising of the bales is avoided, which prevents any cracks and damage to the bale or surrounding film and as a result of its rot in the bale and loss of feed quality. Consequently, there are no costs for removing the rot or disposal of such bales and procurement of substitute feed.
In connection with the aforementioned target position, three functions with respect to a movement drive of the charging device are preferably controlled, namely a position of a boom of the charging device, a position of a tool of the charging device and a clamping force of the tool (eg, forking or clamping forceps). To achieve the desired position, these three functions can be controlled automatically, and at the same time and / or with respect to their drive movements coordinated with each other. Here, in particular a hydraulic cylinder are controlled for each function.

Due to the aforementioned storage only a stored desired position must be requested again, whereby the required hydraulic flow or the hydraulic volume to achieve this target position can be determined very accurately in advance. In addition, the automatic achievement of the requested target position can replace manual operation of the loader by an operator, thereby reliably avoiding erroneous operation and thus any damage by the loader (e.g., on adjacent buildings, on the load).

The request of a stored desired position by the operator can be done by means of a suitable control device. For example, the operator presses a button on a hand lever, joystick or the like. Alternatively, a touch of one or more optical buttons may be provided on an operator interface (e.g., screen) to initiate drive movement of the charger toward the desired position.

In a further embodiment, an operating foot pedal is provided as an operating device for triggering a drive movement of the charging device, in particular in the direction of a desired position. For this purpose, a conventional clutch pedal is suitable without significant additional technical effort, if it is no longer needed for coupling purposes due to the transmission used in the commercial vehicle (eg IVT transmission). In such cases, the conventional clutch pedal may then be used to raise or lower a loader. This function of the clutch pedal can be fixed in the commercial vehicle. Alternatively, this clutch pedal is optionally configurable with different functions. For this purpose, one of several possible functions can be assigned to the clutch pedal, for example via an operator interface. If necessary, the currently assigned function can be replaced by another function. Thus, the foot pedal can flexibly fulfill different user-specific functions. The signals of the operated foot pedal are preferably processed in a corresponding control unit and converted by this into control signals, for example for controlling the movement of a charging device. Such a foot pedal can improve the ease of operation for the driver and thus reduce his workload during the working movements of the loader to be executed.

The aforesaid drive characteristic in particular includes specific features of the charging device used, e.g. Hydraulic-specific information about the model used and / or its geometric dimensioning.

In another preferred embodiment, the desired hydraulic flow is determined as a function of at least one hydraulic unit (e.g., brake, steering) of the commercial vehicle, thereby further improving accuracy for the requested increase in engine speed.

In order to limit the additional consumption of the drive motor, it is advantageous to request an increase in the engine speed only for a specific period of time, a so-called request period. This request period is determined or calculated in dependence on the determined desired hydraulic flow. The determination of the request period is particularly useful and possible with great accuracy when the desired hydraulic flow is determined for a requested desired position, because then the required to achieve the desired position hydraulic volume with great accuracy known or can be determined , The determined request period may also be further processed for the purpose of deciding whether an increased engine speed is actually maintained for the duration of the request period or for a shorter or longer period of time.

In order to avoid constantly changing increases in the engine speed and thus unnecessary additional consumption, the increased engine speed is preferably limited so that it is at most as large as a predetermined limit speed. At requested engine speeds greater than the limit speed of the drive motor is thus preferably driven at the limit speed.

Further preferably, the engine speed is increased at a predetermined or determined rate of increase and / or lowered after its increase at a certain time with a predetermined or determined lowering speed. As a result, the inertia of the drive motor is taken into account and unnecessarily limited additional fuel consumption of the drive motor.

An increased engine speed is maintained especially for a determined or predetermined hold period. This hold period may be shorter or longer than the aforementioned request period. The holding period is preferably dependent on a consumption-oriented process execution (ie the shortest possible duration for limiting the additional consumption of fuel) or a performance-oriented method implementation (ie relatively long period of time to support the drive power for the charging device and / or the driving performance of the commercial vehicle) predetermined or determined. Also, a predetermination of the holding period in dependence of the determined request period is possible.

According to a further preferred measure, the increased engine speed is initially maintained after the predetermined holding period has elapsed, when the requested engine speed is at least as great as the increased engine speed at the time of the holding period. This measure also helps to avoid constantly changing increases in engine speed and thus unnecessary power consumption for the drive motor.

Overall, the aforementioned measures in connection with the limit speed, the slew rate, the lowering speed and the holding period allow a smoothing of requested increases in engine speed and thus a more uniform drive power of the drive motor while limiting the resulting in the process implementation of additional consumption.

• Fig. 1 eine Seitenansicht eines Traktor mit einem Frontlader in unterschiedlichen Arbeitspositionen,
• Fig. 2 ein Flussdiagramm der Verfahrensdurchführung in einer ersten Ausführungsform,
• Fig. 3 eine blockschaltbildartige Darstellung von Bestandteilen einer Anordnung zur Durchführung des Verfahrens,
• Fig. 4 bis Fig. 8
  Darstellungen der angeforderten Motordrehzahl-Erhöhung und der tatsächlich erhöhten Motordrehzahl in Abhängigkeit der Zeit.

The method according to the invention is explained in more detail below with reference to the attached drawings. With regard to their function, matching or comparable components are identified by the same reference numerals. Show it:

• Fig. 1 a side view of a tractor with a front loader in different working positions,
• Fig. 2 a flowchart of the method implementation in a first embodiment,
• Fig. 3 a block diagram representation of components of an arrangement for carrying out the method,
• Fig. 4 to Fig. 8
  Representations of the requested engine speed increase and the actually increased engine speed as a function of time.

Fig. 1 shows a designed as a tractor 10 commercial vehicle, on its front side designed as a front loader 12 charging device is mounted. The front loader 12 has a pivotable arm 14, at the free end of a tool in the form of a blade 16 is pivotally mounted. The boom 14 and the bucket 16 are hydraulically driven to move to different positions, eg those in FIG Fig. 1 Positions taken Pos_1, Pos_2, Pos_3 and Pos_4 to take. In the positions Pos_1, Pos_2 and Pos_3, the boom 14 assumes different pivot angles relative to the tractor 10. The blade 16 assumes in the positions Pos_1, Pos_2, Pos_3 and Pos_4 different pivot angle relative to the boom 14 a. The position Pos_3 can represent a maximum lifting height of the boom 14 or the charging device 12 in certain work in order to avoid any damage to adjacent buildings, gateways or the like. The hydraulic movement drive takes place by means of suitable hydraulic cylinders 18, which are mounted on the loading device 12.

The method for controlling an engine speed n of a drive motor of the tractor 10 not shown in detail here initially predicts or detects a movement drive of the charging device 12 and then requests an increase in the engine speed n of the drive motor. The increase of the engine speed n is therefore requested, for example, if a future movement drive predicts or a movement drive is actually requested and recognized.

This procedure is according to Fig. 2 in an idling operation of the drive motor is applied as follows. First, the engine speed n corresponds to an idling speed n_L at standstill of the tractor 10 (step S1). The idling speed n_L is for example 850 rpm (revolutions per minute). In a step S2, it is checked whether a status signal S_Z signals an activated operating state (on) or another drive state, eg deactivated operating state (off), of the charging device 12. In the case of a detected activated operating state, it is assumed that a movement drive or a drive movement is subsequently requested with high probability. So a future movement drive is predicted. According to the method, therefore, an increase in the engine speed n is requested. The engine speed n is increased to the engine speed n_H (step S3). It is for example 1000 U / min. At the time of increasing the engine speed n to n_H also a time counter is activated, which starts at t = 0 and at the end of a waiting period .DELTA.t_W, for example, 1 minute ends (step S4). In step S5, it is checked whether a movement drive or a drive movement has already been performed or at least requested when the time duration Δt_W has elapsed. If so, the increased engine speed n_H is maintained (step S6). If not, the increased engine speed n_H is again reduced (step S7) to reduce the increased fuel consumption again. In this case, the increased engine speed n_H in particular to the original idle speed n_L reduced. Subsequently, it is checked in a step S8 whether the operating state of the charging device is still activated (S_Z = on). If this is the case, a return is made to step S5 in order to check whether a motion drive is being executed or at least requested. If so, the engine speed n is increased again (step S6). If it should be determined in step S8 that the operating state of the charging device is no longer activated, the program jumps back to step S2.

Fig. 3 schematically shows parts of an assembly 20 for performing the method for controlling the engine speed n. In particular, the assembly 20 is used to carry out the process at any engine speeds n outside the idle speed n_L. The work blocks 22, 24, 26, 28 shown here are used to implement a control of the engine speed n, which is effective in response to a hydraulic flow to be described below. In another, not shown embodiment of the arrangement 20 further work blocks and components are provided, which also control the engine speed n in idle mode according to Fig. 2 consider.

The arrangement 20 according to Fig. 3 assumes that the charging device 12 and possibly also other units (eg steering, brake) are hydraulically driven. For this purpose, the tractor 10 has a hydraulic drive pump 30. Their pump characteristic (in particular characteristic curve with a hydraulic flow (liters / minute) as a function of the engine speed) is taken into account in the work block 24 in order to determine which higher engine speed n_A is to be requested. In this case, the engine speed n_A to be requested is calculated as a function of a determined setpoint hydraulic flow F_S. In particular, the engine speed n_A is requested for a request time period Δt_A, ie, the engine speed n_A should be effective during the request time period Δt_A.

The request duration .DELTA.t_A is used as the output of the working block 24 in particular when calculated in the working block 28, a required hydraulic volume V_hyd and sent as a signal to the working block 24. In this case, taking into account a current rotational speed n_akt of the drive motor and a requested hydraulic flow F_A, the desired hydraulic flow F_S and, therefrom, the request time duration Δt_A can be determined. The hydraulic volume V hyd represents a hydraulic volume which is estimated or calculated in order to be able to carry out a predicted or detected movement drive of the charging device 12. Here, as input signals, a drive characteristic S_Ch (eg drive type, drive geometry, geometry of the hydraulic cylinders 18, etc.) and a requested drive movement S_Bew (eg requesting specific pivoting movements of the boom 14 and / or the tool 16 by means of appropriate controls) of the charging device 12 are taken into account. When determining the hydraulic volume V_hyd, in particular an input signal S_Pos_S is considered in the working block 28. This signal represents, in particular, the request for an already stored desired position Pos_S of the charging device 12, which is therefore known with regard to the hydraulic requirements. For example, the charging device is in the starting position Pos_1 before the desired position Pos_S is requested. In work block 28, the required hydraulic volume V_hyd can then be predicted with particular accuracy on account of the hydraulically known starting and desired positions and the known drive characteristic S_Ch.

The requested hydraulic flow F_A is an output signal of the working block 22. For this output signal, for example, input signals with respect to the operating state (S_Z) of the charging device 12, a steering (S_L, eg steering angle) of the tractor 10, a braking unit (S_B, eg the status of the brake) and Valve control signals S_V hydraulic valves of the charging device 12 taken into account.

In summary, based on the above explanations, the desired hydraulic flow F S is determined as a function of a movement drive of the charging device 12 predicted or detected in the work block 22 and / or in the work block 28.

The requested engine speed n_A, possibly the request time duration Δt_A and a predetermined limit speed n_G, and optionally further parameters or variables are evaluated in the work block 26. Depending on consumption-oriented (in particular as little as possible additional consumption of fuel), performance-oriented (in particular as quickly as possible implementation of the requested motion drive) and / or stress-oriented (in particular uniform load of the drive motor) viewpoints are from the input signals of the working block 26 an actual to be realized increased engine speed n_H, a holding period .DELTA.t_H for maintaining the increased engine speed n_H, an increased rising speed m_an the engine speed n and a lowering speed m_ab the increased engine speed n_H determined or predetermined and as output signals for controlling the drive motor, in particular a motor control sent out.

Different controls of the drive motor are exemplary based Fig. 4 to Fig. 8 shown. The dot-dash lines show requested increases in the Engine speed n and possibly request periods .DELTA.t_A. The solid line curves show the increased engine speeds n_H and holding periods Δt_H with which the drive motor is actually driven based on the evaluation in the work block 26.

In Fig. 4 is from a time t ₀ at a current speed n_akt the drive motor, a higher speed n_A for a request period .DELTA.t_A requested. For the limit speed n_G, however, a lower value is predetermined in comparison to the requested higher speed n_A. The actually realized increased speed n_H therefore corresponds to the limit speed n_G. From consumption-oriented boundary conditions, the increased speed n_H is maintained only for a holding period of increased engine speed n_H, which is shorter than the request duration Δt_A. In addition, the current speed n_akt is increased at a lower slew rate m_an than was requested to limit excess consumption of fuel and additional loading of the drive motor.

In Fig. 5 is for the time t ₁₅ a higher speed n_A requested. Actually, the rotational speed n is raised at a lower slew rate m_an until the time t ₂₅ . There, the engine speed n initially remains at an increased speed n_H below the limit speed n_G, since a further lowering of the engine speed n was requested here and constant change of the engine speeds should be avoided. From the time t ₃₅ , the requested speed is again greater than the increased speed n_H realized between t ₂₅ and t ₃₅ . The engine speed n therefore continues to increase and is limited at time t ₄₅ as increased engine speed n_H due to the predetermined limit speed n_G. Between times t ₄₅ and t ₅₅ , the increased engine speed n_H is maintained for the hold period Δt_H. Thereafter, the increased engine speed n_H is reduced again with the lowering speed m_ab. For the time t ₆₅ , an increase in the engine speed n is again requested with a value n_A above the limit speed n_G. Accordingly, the engine speed is again increased with a slew rate m_an with a limit by the limit speed n_G (time t ₇₅ ). After expiration of the holding period .DELTA.t_H at time t ₈₅ , the increased engine speed n_H is lowered again with a lowering speed m_ab.

In Fig. 6 is requested for the time t16 a higher engine speed n_A above the limit speed n_G. Consequently, the engine speed n is increased at a predetermined increase speed m_an with the limit speed n_G as the increased engine speed nH. The hold period Δt_H begins at time t ₂₆ and ends at time t ₃₆ . As for this latter Once again a higher speed n_A above the limit speed n_G was requested, the increased engine speed n_H remains maintained. In Fig. 6 it is maintained for another holding period Δt_H.

In Fig. 7 The value of the increased engine speed n_H corresponds to the value of the requested higher engine speed n_A, since the latter is below the limit speed n_G. From the time t ₁₇ , the increased engine speed n_H is maintained for the period of the holding time period Δt_H. Since a higher engine speed n_A is still requested at time t ₂₇ at the end of this first holding time period Δt_H, the increased engine speed n_H remains analogous to that in Al Fig. 6 - maintained for another holding period .DELTA.t_H.

Fig. 8 shows the same requested higher engine speed n_A with the same request period Δt_A as in FIG Fig. 7 , The maintenance of the increased engine speed n_H over a multiple of the hold time Δt_H has in Fig. 7 however, has the disadvantage that it will be maintained for a longer period of time than has been requested with the request period Δt_A. In order to save fuel in such cases, the time intervals for maintaining the increased engine speed n_H in the work block 26 can preferably be predetermined or determined according to the following principle:
If the request period Δt_A is less than the hold period Δt_H, the increased engine speed n_H is maintained over the period of a single hold period Δt_H. If the request period Δt_A is equal to or greater than the hold period Δt_H, the increased engine speed n_H is maintained over the period of the request period Δt_A. In Fig. 8 this means that the increased engine speed n_h after expiration of the holding time period Δt_H only for the period t is maintained ₂₈ to t _38, wherein the period of time t ₁₈ to t ₃₈ of the call-time Δt_A corresponds. This principle of a shortening of the time interval - and thus a limitation of the temporarily increased fuel consumption - for maintaining the increased engine speed n_H can of course also in other variants of an increase in the engine speed n, eg in the variants according to FIG. 4 to FIG. 7 , apply.

Claims (15)

Method for controlling a rotational speed (n) of a drive motor of a commercial vehicle (10) with a drivable charging device (12), wherein - A movement drive of the charging device (12) is predicted or detected, and - When predicted or detected movement drive the charging device (12), an increase in the engine speed (n_A) of the drive motor is requested. A method according to claim 1, characterized in that the engine speed (n) is an idling speed (n_L) at standstill of the commercial vehicle (10). A method according to claim 1 or 2, characterized in that at an increased engine speed (n_H), this is again reduced when a predetermined waiting period (.DELTA.t_W) has expired and until the end of this waiting period (.DELTA.t_W) no movement drive of the charging device (12 ) has been requested. Method according to one of the preceding claims, characterized in that the movement drive of the charging device (12) is predicted or detected as a function of a detected state signal (S_Z), wherein the state signal (S_Z) signals an operating state of the charging device (12). Method according to one of the preceding claims, characterized in that the loading device (12) is hydraulically driven, - A desired hydraulic flow (FS) of a hydraulic drive pump (30) of the commercial vehicle (10) in dependence of the predicted or detected movement drive of the charging device (12) is determined, and - The increase in the engine speed (n_A) in response to the determined desired hydraulic flow (F_S) is requested. A method according to claim 5, characterized in that the desired hydraulic flow (F_S) is determined as a function of a detected valve control signal (S_V) for at least one hydraulic valve of the charging device (12). Method according to one of claims 5 or 6, characterized in that the desired hydraulic flux (F_S) determined in dependence of at least one of the following features becomes: a requested drive movement (S_Bew) of the charging device (12), a drive characteristic (S_Ch) of the charging device (12), - A requested desired position (Pos_S) of the charging device (12). Method according to one of claims 5 to 7, characterized in that the desired hydraulic flow (F_S) in dependence on at least one hydraulic unit (S_L, S_B) of the commercial vehicle (10) is determined. Method according to one of claims 5 to 8, characterized in that the increase in the engine speed (n_A) is requested for a request period (.DELTA.t_A), which is determined in dependence on the determined target hydraulic flow (F_S). Method according to one of the preceding claims, characterized in that the increased engine speed (n_H) is less than or equal to a predetermined limit speed (n_G). Method according to one of the preceding claims, characterized in that the engine speed (n) with a predetermined rate of increase (m_an) is increased. Method according to one of the preceding claims, characterized in that the engine speed (N_H) following its elevation at a predetermined descending speed (m_ab) is lowered. Method according to one of the preceding claims, characterized in that the increased engine speed (n_H) for a holding period (Δt_H) is maintained. A method according to claim 13, characterized in that the increased engine speed (n_H) after the holding period (.DELTA.t_H) is maintained, if at the time of the expiration of the holding period (.DELTA.t_H), the requested engine speed (n_A) is at least as large like the increased engine speed (n_H). Method according to one of the preceding claims, characterized in that the loading device has a front loader (12), in particular consists of a front loader (12).

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