MOBILE WORK MACHINE AND METHOD FOR OPERATING A MACHINE OF THIS TYPE

Abstract

The present invention relates to a mobile work machine, in particular a hydraulic excavator, which comprises an engine for driving the mobile work machine, a hydraulic power generation unit which is coupled to the engine and is designed to convey a hydraulic volume in a manner which is dependent on a rotational speed of the engine, and a plurality of hydraulic elements which can be actuated by way of the conveyed volume of the hydraulic power generation unit and are assigned to various functions of the mobile work machine. The machine is characterized by a control unit for detecting a defined operating mode of the mobile work machine, wherein the control unit is designed to set the setpoint rotational speed of the engine in a manner which is dependent on the detected defined operating mode.

Claims

1. A mobile work machine comprising: an engine for driving the mobile work machine; a hydraulic power generation unit coupled to the engine and adapted to convey a hydraulic volume in dependence on a speed of the engine; and a plurality of hydraulic elements actuable by the conveyed volume of the hydraulic power generation unit and associated with different functions of the mobile work machine, and a control device for recognizing a specific operating mode of the mobile work machine, wherein the control device is adapted to set a desired speed of the engine in dependence on the recognized specific operating mode.

2. The machine in accordance with claim 1, wherein the specific operating mode has a fixed cyclic procedure of an actuation sequence of the plurality of hydraulic elements and the control device is adapted to set the desired speed of the engine in dependence on a current cycle phase of the cyclic procedure during a recognized specific operating mode.

3. The machine in accordance with claim 1, wherein a fixed cyclic routine of an actuation sequence comprises a plurality of cycle phases that can be associated with a work process of the machine.

4. The machine in accordance with claim 1, wherein at least one respective hydraulic element is associated with digging, lifting, rotating, unloading, pivoting back, and/or driving.

5. The machine in accordance with claim 1, wherein a transfer case is provided between the engine and the hydraulic power generation unit wherein the transfer case is driven by the engine and drives the hydraulic power generation unit.

6. The machine in accordance with claim 1, wherein the hydraulic power generation unit outputs a constant volume flow, wherein a starting volume flow is proportional to a drive speed of the hydraulic power generation unit.

7. The machine in accordance with claim 6, wherein the hydraulic power generation unit has a dividing device to carry out an actuation speed of the plurality of hydraulic elements by a division of the starting volume flow.

8. The machine in accordance with claim 1, wherein the control device is further adapted to operate the engine at a nominal speed provided that the specific operating mode of the mobile work machine has not been recognized.

9. The machine in accordance with claim 1 further comprising sensors for detecting a state of the different functions of the mobile work machine, wherein a signal from the sensors is provided to the control device together with control signals for the machine to recognize the specific operating mode of the mobile work machine.

10. A method of operating a mobile work machine, wherein, in the method, actuation of the machine is checked for a specific operating mode; and if such specific operating mode has been recognized, the desired speed of the engine is set in dependence on the recognized specific operating mode, with the specific operating mode having a fixed cyclic routine of an actuation sequence of a plurality of hydraulic elements of the machine.

11. The method in accordance with claim 10, wherein furthermore: after a start of the machine, the engine is operated at a nominal speed until the specific operating mode has been recognized and the desired speed of the engine is set in dependence on the recognized specific operating mode; and this state is maintained until a different specific operating mode has been recognized so that the desired speed of the engine is set in dependence on the recognized different specific operating mode and/or a specific operating mode has no longer been recognized so that the nominal speed is again set.

12. The method in accordance with claim 10, wherein a specific operating mode of the machine is characterized by the fixed cyclic routine of the actuation sequence of the plurality of hydraulic elements of the machine.

13. The method in accordance with claim 12, wherein the fixed cyclic routine of the actuation sequence comprises a plurality of cycle phases that are associated with a work procedure of the machine.

14. A mobile work machine comprising: an engine for driving the mobile work machine; a hydraulic power generation unit coupled to the engine and adapted to convey a hydraulic volume in dependence on a speed of the engine; and a plurality of hydraulic elements actuable by the conveyed volume of the hydraulic power generation unit and arc associated with different functions of the mobile work machine, and a control device configured to recognize a specific operating mode of the mobile work machine; and if such a specific operating mode has been recognized, set the desired speed of the engine in dependence on the recognized specific operating mode, with the specific operating mode having a fixed cyclic routine of an actuation sequence of a plurality of hydraulic elements of the machine.

15. (canceled)

16. The machine in accordance with claim 3, wherein the plurality of cycle phases of the work process comprise digging, lifting, rotating, lifting and rotating, unloading, pivoting back, driving, and/or work preparation.

17. The machine in accordance with claim 5, wherein the transfer case has a fixed gear ratio.

18. The machine in accordance with claim 7, wherein the hydraulic power generation unit has a tank provided for receiving a starting volume flow not required for the supply to the plurality of hydraulic elements.

19. The method in accordance with claim 12, wherein a desired speed of the engine is set in accordance with the current cycle phase of the cyclic routine during a recognized specific operating mode.

20. The method in accordance with claim 13, wherein the plurality of cycle phases of the work procedure comprises digging, lifting, rotating, lifting and rotating, unloading, pivoting back, traveling, and/or work preparation.

21. The method in accordance with claim 20, wherein a respective desired speed of the engine is associated with each cycle phase.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0044] Further features, details and advantages of the invention will become clear with reference to the following description of the Figures. There are shown:

[0045] FIG. 1: the stringing together of a plurality of phases of a specific operating mode that is defined by different work procedures;

[0046] FIG. 2: the representation of an exemplary drive speed in an engine map of a diesel engine used to drive the machine;

[0047] FIG. 3: a representation of the stringing together of cyclic work procedures; and

[0048] FIG. 4: a flowchart that represents the change of the desired speed of the engine.

DETAILED DESCRIPTION

[0049] FIG. 1 shows a diagram in which a desired speed of the engine, preferably of the diesel engine, is entered over the time. Depending on the recognized work procedure of the mobile work machine, a desired speed of the engine suitable for it is set. The work procedures can here inter alia be “digging”, “lifting and rotating”, “unloading”, “pivoting back”, “driving”, “work preparation”, etc., with the invention naturally not being restricted thereto.

[0050] If the control device recognizes a specific operating mode, that is “digging”, for example, in one of these phases, the required hydraulic drive power and the required travel speed of the hydraulic cylinders associated therewith are determined so that a corresponding output speed of the diesel engine (e.g. drive speed A, B, C, and D) and the corresponding required drive power that is required for the generation of the corresponding speeds can now be determined on the basis of this analysis or recognition. The limits are given here by the available power of the (diesel) engine with a fixed map.

[0051] The arrangement of exemplary drive speeds is shown in the engine map in FIG. 2 that are specified as the drive speed to the (diesel) engine in dependence on the cycle phase. Different sensors and control signals are monitored within the machine for the recognition of the cycle phase.

[0052] Phase 4 of FIG. 1 here shows a desired speed A that, as can be seen from FIG. 2, stands for a high speed of the engine at a small power. This speed is accordingly possible for a pivoting back of the superstructure of the machine since high amounts of a fluid volume flow are required for this purpose and the required power simultaneously does not have to be excessively high. This is different, for example, at speed C in phase 3; a mean speed, that therefore combines a mean volume flow and simultaneously a very high power of the conveyed volume flow, is applied here at a maximum power. This is suitable for power-intense work that simultaneously requires a mean volume flow of the fluid in the hydraulic elements. In phase 2 of FIG. 2, in contrast, a higher speed of the engine is set so that the work deployment carried out here requires a higher volume flow of hydraulic fluid than in phase 3, but does not reach the very high power of this phase. Finally, it can be seen from the map that the power at this point B is equal to the power at point C despite the higher speed of the engine so that the engine has to have a smaller torque at point B which in turn effects a smaller (pressure) power or displacement power of the volume flow. This is thus in turn also suitable for a very specific piece of work of the machine.

[0053] If therefore an operating mode such as digging, unloading, rotating back, or the like is recognized, the optimum speed of the engine for this is set.

[0054] FIG. 3 shows a change of the desired speed with a cyclically repeating piece of work that can be divided into a plurality of actuations of the machine.

[0055] FIG. 3 here has the identical designation of the coordinate axes as in FIG. 1 and shows a plurality of cycles Z1, Z2, Z3 of a cyclically carried out piece of work of the machine.

[0056] The same sequence of work is thus carried out by the machine in every cycle Z1, Z2, Z3. Digging is performed in phase 1, that is the bucket of an excavator is filled with soil, for example. The maximum power is required for this so that this is done at the speed C. A look at FIG. 2 shows that this speed of the engine delivers more power than the other speed values A, B, or D.

[0057] Subsequent to this, the superstructure is pivoted and the filled bucket is raised.

[0058] The bucket is opened in phase 3 and the soil therein is unloaded before the machine is again moved into a state directly before a repeat “digging” in phase 4. The cycle then begins from the start.

[0059] FIG. 4 shows a flow change for the method of the present invention. The control device of the machine can here implement the routine then listed.

[0060] The flowchart for the change of the desired speed of the engine is shown in FIG. 4. On the start of the machine, the engine is operated at the nominal speed that corresponds to the speed at which the travel speed can be reached that serves as the basis for the configuration of the machine. If now, on the basis of the sensor signals and control signals, an operating mode is recognized that is associated with a previously defined drive speed, the desired speed of the engine is correspondingly influenced. A change back to the nominal speed is made by the continuous monitoring of the work of the machine if no defined operating mode is recognized. It is hereby achieved that the machine can be operated at its nominal starting power with a not previously defined or unrecognized operating mode.