Method, system and computer program product for controlling at least one electric motor-driven hydraulic pump of a hydraulic chassis of a motor vehicle

Abstract

The invention relates to a method for controlling at least one electric motor-driven hydraulic pump (7, 8) of a hydraulic chassis (20) of a motor vehicle which is driven, inter alia, at different speeds, accelerations and on different surfaces, whereby operational driving situations arise in which the hydraulic chassis (20) is subjected to more or less heavy loads. In order to make the control of an electric motor-driven hydraulic pump (7, 8) energy-efficient, the electric motor-driven hydraulic pump (7, 8) is specifically controlled using a variable control method depending on a currently detected and / or recognized load on the hydraulic chassis (20).

Description

[0001] The invention relates to a method, a system and a computer program product for controlling at least one electric motor-driven hydraulic pump of a hydraulic chassis of a motor vehicle which is driven, among other things, at different speeds, accelerations and on different surfaces, whereby operational driving situations arise in which the hydraulic chassis is subjected to more or less heavy loads.

[0002] German patent application DE 10 2006 027 713 A1 discloses a method for calculating current control signals for controlling a machine located in a vehicle, the method comprising: determining an operating range of the machine based on the voltage limit of an inverter in the machine; determining a current reference signal for controlling the torque of the machine based on the determined operating range, wherein calculating the current reference signal includes using one of a plurality of equations that optimize the current reference signal based on the determined operating range;and applying the current control signals to the machine based on the calculated current reference signal. German Offenlegungsschrift DE 10 2021 131 845 A1 discloses the control of an electric traction machine of a vehicle, wherein the control can be carried out by means of space vector modulation or discontinuous pulse width modulation, wherein the selection is made based on driving data. German Offenlegungsschrift DE 10 2020 131 509 A1 discloses a method for controlling a converter in a motor vehicle, wherein the converter converts a direct voltage from an electrical energy source of the motor vehicle into an alternating voltage and outputs it to an electric machine, the method comprising the following steps: receiving a user selection;Adaptation of a modulation method used by the converter to convert the direct voltage into the alternating voltage depending on the user selection, whereby the modulation method used is selected from the following modulation methods: continuous pulse width modulation via sine pulse width modulation, sine pulse width modulation with injection of a third harmonic or space vector modulation, each with asynchronous or synchronous and constant or variable clock frequency, as well as discontinuous or discrete pulse width modulation at constant or variable clock frequency, block commutation and direct self-regulation via a hysteresis controller or direct self-regulation in combination with a pulse width modulation method.;

[0003] The object of the invention is to make the control of an electric motor-driven hydraulic pump of a hydraulic chassis of a motor vehicle energy-efficient overall.

[0004] The problem is solved by a method for controlling at least one electric motor-driven hydraulic pump of a hydraulic chassis of a motor vehicle, which is driven at various speeds, accelerations, and on different surfaces, among other things, whereby operational driving situations arise in which the hydraulic chassis is subjected to greater or lesser loads. The method involves specifically controlling the electric motor-driven hydraulic pump using a variable control method depending on a currently detected and / or recognized load on the hydraulic chassis. This allows the electric motor-driven hydraulic pump to be controlled in a very energy-efficient manner during more stationary operation of the motor vehicle, for example, when driving a long stretch of highway at a relatively constant speed.If required, the electric motor-driven hydraulic pump can be controlled with high dynamics in a more sporty mode of operation of the vehicle, for example when driving on a race track.

[0005] A preferred embodiment of the method is characterized in that the variable control method switches between different modulation types depending on at least one of the following parameters: vehicle speed, acceleration in a longitudinal direction of the vehicle, acceleration in a transverse direction of the vehicle, and road surface conditions. Thus, energy can be effectively saved using relatively simple means without noticeably impairing the function of the hydraulic suspension during operation of the motor vehicle.

[0006] A further preferred embodiment of the method is characterized in that the variable control method switches between space vector modulation and discontinuous pulse width modulation. Space vector modulation is referred to as space vector modulation. The different modulation types are known per se.

[0007] A further preferred embodiment of the method is characterized in that the variable control method switches to block commutation as needed. This control variant is also known per se. By switching between the individual modulation types, the hydraulic pump of the hydraulic chassis can be operated in an overall energy-efficient manner.

[0008] A further preferred embodiment of the method is characterized in that the electric motor-driven hydraulic pump is controlled with space vector modulation during comfort-oriented operation of the motor vehicle on a slippery road below a limit speed. In this operating mode of the motor vehicle, relatively low wheel and body accelerations occur. This operating mode is, for example, a normal driving mode in which low lateral and longitudinal accelerations of the motor vehicle occur.

[0009] Another preferred embodiment of the method is characterized in that the electric motor-driven hydraulic pump is controlled with discontinuous pulse width modulation during comfort-oriented operation of the motor vehicle above the limit speed. The limit speed can be preset or selected. The selected control variant can be used to particularly advantageously optimize the acoustics during operation of the hydraulic suspension.

[0010] A further preferred embodiment of the method is characterized in that, during comfort-oriented operation of the motor vehicle on an uneven road above the limit speed, the electric motor-driven hydraulic pump is controlled with discontinuous pulse width modulation, with a switch to block commutation taking place in a high load and speed range. This improves the function of the hydraulic chassis at high wheel and body accelerations. The motor vehicle is operated, for example, in a normal driving mode, in which relatively low lateral and longitudinal accelerations occur on the vehicle.

[0011] A further preferred embodiment of the method is characterized in that the electric motor-driven hydraulic pump is controlled with discontinuous pulse width modulation during sporty operation of the motor vehicle on a slippery road above a limit speed, with a switch to block commutation taking place in a high load and speed range. The motor vehicle is operated, for example, in a sport mode or in a sport plus mode, in which high lateral and longitudinal accelerations occur on the motor vehicle, particularly on a racetrack.

[0012] In a system for controlling an electric motor-driven hydraulic pump of a hydraulic chassis of a motor vehicle according to a method described above, the above-mentioned object is achieved alternatively or additionally in that the electric motor-driven hydraulic pump is combined with a control logic that switches between at least two different control variants depending on a current driving situation. The claimed system advantageously comprises an actuator device in which the hydraulic pump is combined with an electric motor and an electronic control system for the electric motor. In the actuator device, two electric motor-driven hydraulic pumps are particularly advantageously combined with one another per axle of the motor vehicle.

[0013] The invention further relates to a computer program product, in particular in an actuator device, comprising instructions that, when the computer program is executed by a computing device, cause the computing device to execute a previously described method. The computer program product is advantageously used in the actuator device in which an electric motor used to drive an electric motor-driven hydraulic pump in a hydraulic chassis is controlled via a suitable electronic controller.

[0014] Further advantages, features, and details of the invention will become apparent from the following description, in which various embodiments are described in detail with reference to the drawings. They show: Fig. 1 shows a schematic representation of a method for controlling at least one electric motor-driven hydraulic pump of a hydraulic chassis of a motor vehicle; and Fig. 2 a schematic representation of an axle of a motor vehicle with a hydraulic actuator device.

[0015] In Fig. In Figure 2, two wheels 1, 2 of one axle of a motor vehicle are indicated only by two circles. Rectangles indicate two hydraulic dampers 3, 4, which are assigned to the two wheels 1, 2. The hydraulic dampers 3, 4, in combination with a hydraulic actuator device 5, serve to represent a system 10 for active damping control during operation of the motor vehicle.

[0016] The hydraulic actuator device 5 comprises two hydraulic pumps 7, 8, which can be controlled separately via a common electrical control unit 6. The hydraulic pump 7 is hydraulically connected to the hydraulic damper 3, which is also referred to as the damper for short, via hydraulic lines 11, 12. Similarly, the hydraulic pump 8 is hydraulically connected to the damper 4 via hydraulic lines 13, 14.

[0017] Fig. Figure 1 illustrates an axle of a hydraulic chassis 20 of a motor vehicle comprising at least two axles. The motor vehicle (not shown in detail) preferably comprises four wheels, each of which is assigned a hydraulic damper. The hydraulic damper represents a shock absorber in an active chassis of the motor vehicle.

[0018] The hydraulic medium used to operate the hydraulic chassis 20 is preferably a hydraulic fluid, also referred to as hydraulic oil or, for short, simply oil. In addition to the hydraulic damper volume, the hydraulic damper advantageously comprises a gas reservoir with a compensation volume. The damping control is preferably an active damping control.

[0019] In Fig. 2, the two electric motor-driven hydraulic pumps 7, 8 are controlled via a common electrical control 6 in the hydraulic actuator device 5. Of course, each of the two electric motor-driven hydraulic pumps 7, 8 can also be assigned a separate electrical control.

[0020] In Fig. 1, three rectangles indicate an input 21, a variable control method 22 and an actuator device 23. The actuator device 23 is, for example, the hydraulic actuator device 5 in Fig. 1.

[0021] The actuator device 23 comprises the hydraulic pump 7 from Fig. 1, which is driven by an electric motor 50 (only indicated). The electric motor 50 is controlled by a controller 51 (also only indicated) using the variable control method 22. The variable control method 22 comprises various control variants or modulation types 41 to 45.

[0022] These are, for example, a space vector modulation 41, a discontinuous pulse width modulation 42 and a block commutation 43. The reference numeral 44 illustrates a switching between the discontinuous pulse width modulation 42 and the block commutation 43. The reference numeral 45 denotes a further control method not described in detail.

[0023] A double arrow 40 indicates Fig. 1 indicates that within the scope of the variable control method 22, switching takes place between the different modulation types or control variants 41 to 45 in order to control the electric motor-driven hydraulic pump 7 in an energy-efficient manner.

[0024] The input 21 for the variable control method 22 includes, for example, a vehicle speed 31, accelerations 32 and a driving surface condition 33. The vehicle speed 31 varies greatly during operation of the motor vehicle.

[0025] To optimize the switching processes between the individual control variants 41 to 45, at least one limit speed can be selected or preset. The accelerations 32 include both accelerations in the longitudinal direction of the vehicle, also referred to as longitudinal accelerations, and accelerations in the transverse direction of the vehicle, also referred to as lateral accelerations.

[0026] The driving surface conditions 33 also vary considerably. In extreme cases, the driving surface conditions 33 vary between a smooth road surface, for example, on a motorway, and a very uneven surface, for example, on a field track or in an undeveloped or only inadequately developed area.

[0027] In the variable control method 22, the actuator device 23 independently switches between the various control variants or modulation types 41 to 45. This enables energy-efficient operation of the hydraulic suspension for low-dynamic control requirements. At the same time, robust and dynamic control is enabled for high-dynamic control requirements. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2006 027 713 A1

[0002] DE 10 2021 131 845 A1

[0002] DE 10 2020 131 509 A1

[0002]

Claims

[1] Method for controlling at least one electric motor-driven hydraulic pump (7, 8) of a hydraulic chassis (20) of a motor vehicle which is driven, inter alia, at different speeds, accelerations and on different surfaces, whereby operational driving situations arise in which the hydraulic chassis (20) is subjected to more or less heavy loads, characterized by that the electric motor-driven hydraulic pump (7, 8) is specifically controlled with a variable control method (22) depending on a currently detected and / or recognized load on the hydraulic chassis (20). [2] Method according to claim 1, characterized bythat in the variable control method (22) switching takes place between different types of modulation depending on at least one of the following parameters: vehicle speed (31), acceleration (32) in a vehicle longitudinal direction, acceleration in a vehicle transverse direction, driving surface condition (33). [3] Method according to one of the preceding claims, characterized by that in the variable control method (22) switching takes place between a space vector modulation (41) and a discontinuous pulse width modulation (42). [4] Method according to claim 3, characterized by that in the variable control method (22) a switch is made to a block commutation (43) if required. [5] Method according to claim 3 or 4, characterized bythat the electric motor-driven hydraulic pump (7, 8) is controlled with the space vector modulation (41) in a comfort-oriented operation of the motor vehicle on a slippery road below a limit speed. [6] Method according to claim 5, characterized by that the electric motor-driven hydraulic pump (7, 8) is controlled with the discontinuous pulse width modulation (42) in the comfort-oriented operation of the motor vehicle above the limit speed. [7] Method according to claim 5 or 6, characterized by that the electric motor-driven hydraulic pump (7, 8) is controlled with the discontinuous pulse width modulation (42) in the comfort-oriented operation of the motor vehicle on an uneven road above the limit speed, wherein a switch to block commutation (43) takes place in a high load and speed range. [8] Method according to one of claims 3 to 7, characterized bythat the electric motor-driven hydraulic pump (7, 8) is controlled with the discontinuous pulse width modulation (42) in a sporty operation of the motor vehicle on a slippery road above a limit speed, wherein a switch to block commutation (43) takes place in a high load and speed range. [9] System for controlling an electric motor-driven hydraulic pump (7, 8) of a hydraulic chassis of a motor vehicle according to a method according to the preceding claims, characterized by that the electric motor-driven hydraulic pump (7,8) is combined with a control logic which switches between at least two different control variants depending on a current driving situation. [10] Computer program product, in particular in an actuator device, comprising instructions which, when the computer program is executed by a computing device, cause the computing device to carry out a method according to one of claims 1 to 8.

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