Method for operating at least one electromechanical actuator of a motor vehicle and motor vehicle

Abstract

Method for operating at least one electromechanical actuator (2) of a motor vehicle (1), wherein the actuator (2) is designed to convert mechanical power into electrical power, which is fed into an energy storage device (3) of the motor vehicle (1), during operation of the motor vehicle (1) in stochastically occurring feed-in processes depending on a feed-in efficiency specified by a feed-in operating point of the actuator (2), wherein the start of a feed-in process is detected by a detection means (10) and at the start of the feed-in process an feed-in operating point of the actuator (2) is set in which the feed-in efficiency is 50% or less.

Description

[0001] The invention relates to a method for operating at least one electromechanical actuator of a motor vehicle, wherein the actuator is configured to convert mechanical power into electrical power, which is fed into an energy storage device of the motor vehicle, during stochastically occurring feed-in processes, depending on a feed-in efficiency determined by a feed-in operating point of the actuator. The invention further relates to a motor vehicle.

[0002] When stochastic and / or highly dynamic loads are integrated into a vehicle's electrical power grid, the energy fed back into the grid by these loads must be accounted for in the form of a reserve capacity in the grid's energy storage system. This reserve capacity represents a portion of the energy storage system's total capacity, which is used to absorb the electrical energy generated by the stochastic load. This reserve ensures grid stability, as it prevents grid overload caused by stochastic and therefore unpredictable feed-in events, provided the energy can be absorbed by the storage system. However, a disadvantage is that this reserve reduces the total capacity of the energy storage system available for other purposes.

[0003] Various methods for handling energy fed into the electrical system of a motor vehicle are known from the state of the art.

[0004] KR 20180008970 A describes a device for controlling a braking current fed into the electrical system of a motor vehicle. If the charging capacity of individual battery cells in the vehicle's energy storage system is insufficient, a bypass function of the device is activated, so that the braking current is converted into heat via a resistor. This prevents the current from being fed into the bypassed battery cell.

[0005] A method for charging a battery is known from CN 105818708 A. In this method, current generated by an electric motor connected to the battery is supplied to a heating device when the temperature of the energy storage device is below a predetermined limit. If the limit is exceeded, the current is instead fed into the battery.

[0006] DE 10 2016 117 153 A1 discloses a method for conditioning a vehicle battery of a hybrid vehicle with an electrically driven cooling system. If the temperature of the battery is higher than a predetermined threshold, at least part of the current generated by the electric motor during recuperation braking is not fed into the battery, but directed to the cooling system to cool the battery.

[0007] From EP 2 097 304 B1, a method for controlling a hybrid drive of a motor vehicle is known. The hybrid drive comprises an internal combustion engine, an electric motor, and an energy storage device. In recuperation mode, electrical energy is generated by the electric motor and supplied to the energy storage device. The rotational speed and torque of the electric motor are taken into account, and the efficiency of energy generation is considered for selecting an operating mode of the hybrid drive.

[0008] DE 101 21 962 A1 describes an energy management system for an electrical vehicle electrical system consisting of at least one generator, at least one energy storage unit, and a multitude of consumers. The energy distribution within the system is controlled by taking into account the efficiency of the individual components involved in power generation, storage, and consumption. To determine the overall efficiency of the energy storage unit, which consists of at least one energy storage device, the state of charge, the temperature of the storage device, and the absolute magnitude of the charging and discharging currents are considered.

[0009] The invention is based on the objective of providing a method which enables a reduction of the reserve capacity of an energy storage device.

[0010] To solve this problem, a method of the type mentioned at the outset is provided according to the invention in such a way that the start of a feed-in process is detected by a detection means and at the start of the feed-in process an operating point of the actuator is set in which the feed-in efficiency is 50% or less.

[0011] This advantageously allows only a small proportion of the mechanical power acting on the actuator to be converted into electrical power due to the low feed-in efficiency. This reduces the electrical power delivered to the energy storage device or the vehicle's electrical system encompassing the energy storage device during the feed-in process. Consequently, the reserve capacity that must be maintained in the energy storage device to absorb this power is also reduced. This advantageously allows for the stability of the energy storage device or the vehicle's electrical system encompassing the energy storage device to be achieved even without, or with a reduced reserve capacity in, the energy storage device.

[0012] The electromechanical actuator of the vehicle is connected to the energy storage device, for example, via the vehicle's electrical system, so that electrical energy can be transferred from the actuator to the energy storage device during the power supply cycles. These power supply cycles of the electromechanical actuator occur stochastically, whereby "stochastic" in this context means that the timing, number, and frequency of the power supply cycles are not determined or cannot be determined by the vehicle. This can be caused, for example, by unpredictable and / or undetected influences acting on the vehicle that trigger the occurrence of the respective power supply cycles. Stochastic power supply cycles can occur particularly with actuators that do not contribute to vehicle propulsion or that are not traction motors of the vehicle.

[0013] The electromechanical actuator is therefore preferably different from a vehicle's traction motor. In a vehicle's traction motor, stochastic power supply processes generally do not occur, since the motor or generator operation of the traction motor is deterministic. Thus, the control unit designed to operate the motor knows at any given time which operating state exists or which operating state will be set upon a subsequent change in operating parameters. An actuator of this type could be, for example, an adaptive damping device or an adaptive suspension damper, but also any other actuator different from the traction motor.

[0014] The detection device can detect the start of a power feed-in process, thus enabling the detection of the beginning of electrical power being fed back into the vehicle's electrical system via the actuator before the electrical power, or at least a significant portion of it, is fed into the energy storage system and / or generated by the actuator. When the detection device detects the start of such a feed-in process, the actuator adjusts to a feed-in operating point at which the feed-in efficiency is 50% or less. The feed-in efficiency indicates the proportion of mechanical power that is converted into electrical power. At a feed-in efficiency of 50%, half of the mechanical power is converted into electrical power by the actuator. The remaining half is converted into thermal power, which, for example, causes the actuator to heat up.A feed-in efficiency of less than 50% therefore means that more thermal power than electrical power is generated from the mechanical power.

[0015] The feed-in efficiency can also be considered in relation to the conversion of mechanical energy into electrical or thermal energy, since the time it takes to generate or convert the respective power is the same for all three forms of energy, or rather, corresponds to the duration of the feed-in process. Consequently, the feed-in efficiency can also be viewed as the proportion of mechanical energy that is converted into electrical energy via the actuator, with the remaining proportion being converted into thermal energy or heat.

[0016] The thermal power generated due to the low feed-in efficiency heats the actuator and / or components coupled to it, and therefore does not need to be absorbed by the energy storage system. This thermal power is absorbed via the thermal capacity of the actuator and other vehicle components connected to it. The remaining proportion of electrical power fed into the system is thus significantly lower than with a higher feed-in efficiency, allowing for a beneficial reduction in the proportion of the total capacity that must be reserved in the energy storage system. This increases the capacity available for other functions of the energy storage system, particularly for energy absorption from the vehicle's electric traction motor.

[0017] Furthermore, it is ensured that the stochastically occurring power supply processes of the actuator do not cause any limit exceedances in the load of the energy storage device or of the vehicle electrical system comprising the energy storage device and at least one actuator. By avoiding stochastic or non-deterministic limit exceedances during the power supply processes of the electromechanical actuator, the occurrence of instabilities in the vehicle electrical system can be prevented. Conditions in which increased component load and / or other critical effects occur can also be avoided.

[0018] The increased usable capacity of the energy storage system resulting from its reduction in size and / or the elimination of the reserve capacity can lead to an optimization, particularly of the vehicle's recuperation phases. This can advantageously improve the vehicle's CO2 potential and overall efficiency, as a larger energy storage capacity is available for other functions, especially for absorbing electrical power or energy generated during recuperation by the vehicle's traction electric motor.

[0019] The feed-in operating point can be determined based on a desired mechanical behavior of the actuator during the feed-in process and / or a specific actuator parameter. In this way, the mechanical behavior of the actuator at the feed-in point can be predefined. This mechanical behavior can also be achieved with the reduced feed-in efficiency. The desired mechanical behavior of the actuator and / or the specific actuator parameter can be determined, for example, by a control unit specifically designed to execute the process, or transmitted to such a control unit from another control device.

[0020] According to the invention, it can be provided that the feed-in efficiency is 25% or less at the set feed-in operating point. In particular, the feed-in efficiency at the set feed-in operating point can also be 20% or less, 15% or less, 10% or less, 5% or less, 2% or less, or 1% or less.

[0021] Preferably, the feed-in efficiency is chosen to be as low as possible, so that the electrical power or amount of electrical energy generated during the feed-in processes is kept as low as possible. A feed-in efficiency of 0% or at least substantially 0% is particularly preferred, so that all mechanical power acting on the actuator is converted into thermal power via the actuator, and no or virtually no electrical power needs to be fed into the energy storage system. The lower the feed-in efficiency during the feed-in processes, the smaller the reserve power required for the at least one electromagnetic actuator in the energy storage system. With a feed-in efficiency of 0%, the reserve power can be completely omitted.

[0022] In a preferred embodiment of the invention, it can be provided that an actuator is used which is designed to be operated in at least one actuator operating point during the operation of the motor vehicle, wherein an operating efficiency with which the actuator converts electrical power into mechanical power is specified by the actuator operating points and the operating efficiency is 80% or more in each case.

[0023] The operating efficiency relates to the conversion of electrical power into mechanical power, whereby the portion of the electrical power that is not converted into mechanical power is accordingly converted into thermal power within the actuator. Preferably, the operating efficiency with which the actuator is operated during the actuator's operating processes is chosen to be as high as possible, preferably 80% or more. In this way, the at least one actuator can be operated from the energy storage system as efficiently as possible during the actuator's operating processes, so that the electrical power drawn from the energy storage system can be optimally converted into the mechanical power necessary to perform the required function of the actuator, and unnecessary energy withdrawal from the energy storage system for the actuator's operation can be advantageously avoided.Corresponding to the feed-in operating point, the actuator operating point can also be selected depending on a desired mechanical behavior of the actuator.

[0024] According to the invention, the duration of the feed-in processes generated by the actuator during operation of the motor vehicle can be 10 ms or less, in particular 1 ms or less, and / or the mechanical power of 1 kW or more can be converted by the actuator during the feed-in processes. Using the lowest possible feed-in efficiency is particularly advantageous for electromechanical actuators that feed into the electrical energy storage system with high dynamics, i.e., with comparatively short feed-in durations. Furthermore, the necessary reserve capacity is particularly large for such actuators when comparatively large mechanical powers of 1 kW or more can be converted into electrical power during the feed-in processes and thus fed back into the energy storage system.

[0025] In a preferred embodiment of the invention, an electromechanical actuator is used which is connected to the energy storage device via a control device, wherein the operating point of the electromechanical actuator is set by controlling the control device. For this purpose, the control device can, for example, be connected to or include a control unit configured for carrying out the method according to the invention. The control device can, for example, be designed as a converter with which a direct current drawn from the energy storage device can be converted into an alternating current for operating the electromechanical actuator during actuator operation, or with which an alternating current generated by the electromechanical actuator can be converted into a direct current during power-up operations.The actuator can be designed as an electric machine, for example as a rotary motor or a linear motor.

[0026] According to the invention, an adaptive damping device, in particular an adaptive suspension damper, can be used as the electromechanical actuator. An adaptive damping device, such as an adaptive suspension damper, can generate a deflection of the damping device at each of the actuator's operating points. During the power supply processes, the damping device is compressed, for example, so that, conversely to the movement at an actuator's operating point, a conversion of mechanical power into electrical power takes place.

[0027] An actuator designed as an adaptive damping device or adaptive suspension damper can, for example, include an electric motor. In addition, such an actuator can include further elements, such as one or more springs and / or one or more mechanical components, for example, a compressible or extendable linkage, a piston, or similar. The adjustment of the input operating point in an adaptive damping device or adaptive vehicle damper can be made depending on the desired damping characteristic.

[0028] An adaptive suspension damper, which is used as an electromechanical actuator, and / or other adaptive damping devices of a motor vehicle can be controlled depending on the current driving condition of the vehicle. The compression processes and the power supply processes of the electromechanical actuator also occur depending on the current operating condition; these are stochastic and cannot be predicted by a control unit of the motor vehicle with regard to the timing and / or frequency of their occurrence and / or the mechanical power to be implemented in each case.

[0029] This is primarily due to the fact that adaptive damping devices, especially adaptive suspension dampers, can be excited by unevenness in the road surface during vehicle operation. In particular, the spring compression processes associated with feeding energy into the energy storage device depend strongly on the nature of the road surface or the underlying road surface, both in terms of the timing and frequency of their occurrence and the mechanical power absorbed by the actuator. It is advantageously possible to use the method with several adaptive damping devices in a vehicle, for example, with four adaptive suspension dampers, each assigned to one wheel of the vehicle.

[0030] According to the invention, a current measuring device can be used as a detection means, wherein the current measuring device measures a current generated by the actuator during the feed-in process. By measuring a current generated by the actuator, the start of a feed-in process can be detected, so that the feed-in operating point of the actuator can be adjusted accordingly, for example, by controlling the control device connected to the actuator. The current measuring means can advantageously also be used in the actuator's operating processes and, in particular, for adjusting the actuator's operating point, so that no additional sensor is required as a detection means.

[0031] According to the invention, it can be provided that, upon detection of the start of a power supply process by an actuator control unit associated with the actuator, a torque to be supplied by the actuator is determined, and the power supply operating point is set as a function of the determined torque. Depending on the design of the actuator, the actuator control unit can, for example, be a chassis control system or a damping control system. The actuator control unit can determine a torque to be supplied or received by the actuator, for example, as a function of a current driving state of the vehicle and / or as a function of at least one measured value from the detection means upon detection of the start of the power supply process.Accordingly, the actuator control unit can also determine a torque to be set at an actuator operating point, which is generated via the actuator when the actuator operating point is set.

[0032] For a motor vehicle according to the invention, it is provided that it comprises at least one electromechanical actuator, an energy storage device, a detection means and a control unit, wherein the actuator is configured to convert mechanical power into electrical power, which is fed into the energy storage device, during operation of the motor vehicle in stochastically occurring feed-in processes depending on a feed-in efficiency predetermined by a feed-in operating point of the actuator, wherein the start of a feed-in process can be detected by the detection means, and wherein the control unit is configured to carry out a method according to the invention.

[0033] According to the invention, the energy storage device can be a traction energy storage device and / or the motor vehicle can be a hybrid-electric or a fully electric vehicle. In a hybrid-electric vehicle, which includes both an electric traction motor and a traction motor designed as an internal combustion engine, electrical energy storage devices with a lower total capacity are generally used, so that a reduction in the reserve capacity of the energy storage device is particularly significant as a percentage of the total capacity of the energy storage device. In fully electric vehicles, which can only be driven by at least one electric traction motor, energy storage devices with a larger total capacity are generally used.In this case too, reducing or eliminating a reserve capacity has an advantageous effect, as it increases the total usable capacity and thus, in particular, increases the potential range of the fully electric vehicle.

[0034] All advantages and embodiments described above in relation to the method according to the invention apply accordingly to the motor vehicle according to the invention. Conversely, the descriptions relating to the motor vehicle according to the invention also apply accordingly to the method according to the invention.

[0035] Further advantages and embodiments of the invention will become apparent from the exemplary embodiments described below and from the drawings. These are schematic representations and show: Fig. 1 a schematic side view of an embodiment of a motor vehicle according to the invention, Fig. 2 a block diagram of an embodiment of a method according to the invention, and Fig. 3 a diagram showing the total capacity of an energy storage system.

[0036] In Fig. Figure 1 shows an embodiment of a motor vehicle 1. The motor vehicle 1 comprises at least one electromechanical actuator 2, which is designed as an active suspension damper. The motor vehicle 1 further comprises an energy storage device 3 and an electric traction motor 4. The motor vehicle 1 can be designed as a fully electric vehicle, so that it can only be moved by means of the traction motor 4. Alternatively, it is also possible that the motor vehicle 1 is designed as a hybrid-electric vehicle and additionally comprises an internal combustion engine 5, which is coupled to the electric traction motor 4, in particular mechanically.

[0037] The electrical energy storage device 3 is connected to the electromechanical actuator 2 via a control device 6, whereby the control device enables the electromechanical actuator 2 to be operated via the energy storage device 3 during actuator operation. For this purpose, the control device 6 can, for example, be designed as an inverter and connected to an electric motor 7 of the actuator 2. The electric motor 7 of the actuator 2 can, for example, be designed as a rotary motor or a linear motor. In addition, the actuator 2, which is designed, for example, as an adaptive suspension damper, can include further components, such as a spring and / or other mechanical components like a piston and / or a compressible or extendable linkage, which, for the sake of clarity, are shown in Fig. 1 are not shown.

[0038] The energy storage device 3 and the control unit 6 are connected to each other via the vehicle's electrical system. Depending on the voltage level of the energy storage device, this could be, for example, a 12V system, a 48V system, or a high-voltage electrical system. The control unit may include a DC / DC converter to change the voltage level of the vehicle's electrical system 8 for the operation of the actuator 2 or the electric machine 7 of the actuator 2. The actuator 2 or the electric machine 7 of the actuator 2 is connected to the energy storage device 3 via the vehicle's electrical system 8.

[0039] In addition to actuator operation of actuator 2 at actuator operating points set via the control device 6, it is also possible to feed electrical power from actuator 2 into the electrical energy storage device 3 via the control device 6. The deflection or movement path of the chassis or of actuator 2, which is designed as an adaptive chassis damper, determines the direction of the mechanical power and thus whether current is fed into or drawn from the vehicle electrical system 8.

[0040] For example, current is fed into the system when actuator 2, designed as an active suspension damper, compresses due to uneven road surfaces. Actuator 2 then converts the mechanical power absorbed in this process into electrical power, which is fed into the energy storage device 3. However, this is undesirable because a reserve capacity must be maintained in the total capacity of the energy storage device 3 to prevent overloading of the energy storage device 3 and / or the vehicle's electrical system 8 connected to the energy storage device 3 during the power feed-in processes via actuator 2.

[0041] To reduce this reserve in the overall capacity of the energy storage system and / or to eliminate this reserve entirely, the motor vehicle 1 further includes a control unit 9, which is configured to set a feed-in operating point for the actuator 2 at the start of a feed-in process, at which the feed-in efficiency is 50% or less. The feed-in efficiency refers here to the ratio of the electrical power generated by the actuator 2 to the mechanical power acting on the actuator 2. The efficiency can accordingly also be understood as the ratio between the electrical energy generated by the actuator 2 and the mechanical energy absorbed by the actuator.

[0042] To detect the start of a power feed-in process, the control unit 9 is connected to a detection device 10 of the vehicle 1. The detection device 10 is configured to measure a current generated by the actuator 2 during a power feed-in process. For this purpose, the current measuring device can, for example, determine the current direction and / or the amplitude of phase currents flowing between the control unit 6 and the electric motor 7. In this way, it can be determined whether there is a current feed-in to the vehicle electrical system 8 or the energy storage device 8, or a current draw-off from the vehicle electrical system 8 or the energy storage device 8. The detection device 10 can also be used, in particular, for setting an actuator operating point, so that a detection device that is also used for other purposes can be advantageously employed for detecting the start of the power feed-in process.

[0043] In Fig. Figure 2 shows a flowchart of an embodiment of the method according to the invention. Step S1 represents the initial state of the method.

[0044] In step S2, the start of a power supply process by actuator 2 is detected by means of a current measurement by the detection means 10. The start of a power supply process can occur, for example, when the vehicle's suspension compresses due to uneven road conditions at the electromechanical actuator 2. Such compression of an adaptive suspension damper or other damping devices of the vehicle 1 occurs stochastically and cannot be detected by the control unit 9 and / or other control units of the vehicle 1.

[0045] As a result of the detection of the start of the feed-in process, a feed-in operating point of actuator 2 is set in step S3, at which the feed-in efficiency is 50% or less. The feed-in efficiency depends, for example, when using a d / q transformation during the operation of the control device 6, on the position of the feed-in operating point in a feedback quadrant. The selection of the feed-in operating point can also depend on a damping behavior of actuator 2 to be set, for example, on a torque to be applied by actuator 2 during compression. The damping behavior, or...The torque can be determined, for example, by an actuator control unit 15 designed as a chassis control unit of the motor vehicle 1, for instance, as a function of a measured value from the detection means 10 at the start of the power supply process, and transmitted to the control unit 9 at the start of the detection of the power supply process in step S2. The power supply operating point, and thus the damping behavior or the torque, as well as the power supply efficiency of the actuator 2, can then be set via the control device 6. As a result, the low power supply efficiency does not affect the mechanical behavior of the actuator 2, and the function of an adaptive chassis comprising the actuator 2 is not affected.

[0046] To keep the electrical power generated during the feed-in process as low as possible, it may be provided, in particular, that the feed-in efficiency at the set feed-in operating point is 25% or less, especially 20% or less, 15% or less, 10% or less, 5% or less, 2% or less, or 1% or less. In particular, the feed-in efficiency may also be 0% or at least substantially 0%, so that all or nearly all of the mechanical power converted by actuator 2 during the feed-in process is converted into thermal power.

[0047] The thermal output heats the actuator 2 and / or other components of the vehicle 1 coupled to the actuator 2; no energy is fed back into the energy storage device 3. Due to the short duration of the compression process, even with comparatively high mechanical power, only a small amount of thermal output or heat is generated, which can be absorbed by the thermal capacity of the actuator 2 and / or components coupled to the actuator 2 without causing significant heating of the actuator 2.

[0048] To set the operating point of actuator 2, the control unit 9 activates the control device 6, so that actuator 2 operates at the feed-in point during the feed-in process. After completion of the feed-in process, the procedure returns to the first step S1. The end of the feed-in process can also be determined by the control unit 9 via the detection means.

[0049] Furthermore, it is possible that, starting from state S1, the electromechanical actuator 2 is controlled in actuator mode. This control can, for example, be determined by the actuator control unit 15 of the motor vehicle 1, which is configured as a chassis control unit, and transmitted to the control unit 9 in step S4. To control the actuator 2 for the execution of an actuator operation, the actuator 2 is then operated by the control unit 9 in an actuator operating point in step S5. For this purpose, the control device 6 of the actuator 2 can be controlled by the control unit 9 to set the actuator operating point in the actuator 2. In this actuator operating point, the actuator has an operating efficiency of 80% or more. The operating efficiency describes the proportion of the electrical power or energy consumed by the actuator 2 that is converted into mechanical power or energy via the actuator 2.Energy is converted. After the actuator operation process is complete, the procedure returns to step S1 and can from there repeat the steps described above.

[0050] It is particularly possible that the motor vehicle 1 has more than one electromechanical actuator 2 designed as an active suspension damper. It is also possible that the electromechanical actuator 2 is designed as a different type of damping device and / or that the motor vehicle 1 includes further electromechanical actuators designed as damping devices, which are operated by means of the method described above. In particular, electromechanical actuators can be operated by means of the method which, during operation of the motor vehicle 1, exhibit stochastic power injection processes of a duration of 10 ms or less, and especially of 1 ms or less, and / or through which mechanical power of greater than 1 kW or more is supplied during the power injection processes. It is possible that the control device 9 and the actuator control device 15 are designed as a single control device.

[0051] An actuator 2, designed as an active suspension damper, can, for example, absorb a mechanical power of 6 kW when driving over an uneven surface during operation of the vehicle 1. If a high feed-in efficiency is set, for example 83%, 5 kW of electrical power would be generated and fed into the energy storage device 3. A reserve of such energy must be provided in the energy storage device 3.

[0052] In Fig. Figure 3 schematically represents the total capacity 11 of the energy storage device 3. The total capacity 11 is represented as an area over axis 14, where axis 14 schematically plots the state of charge of the energy storage device 3 between 0% and 100% relative to the total capacity of the energy storage device 3.

[0053] The total capacity 11 has two reserves 12 and 13, with a lower reserve 12 limiting the maximum electrical energy that can be extracted from the energy storage device 3 to a value greater than 0%. The amount of energy retained by reserve 12 can be used, for example, for the operation of actuator 2 and / or for the operation of other actuators of the vehicle 1. Reserve 13 limits the maximum power that can be fed into the energy storage device 3, for example, during recuperation operation of the electric traction motor 4, to a value below 100% of the total capacity 11 of the energy storage device 3. Reserve 13, which is available for energy absorption, prevents overcharging of the energy storage device 3 and the vehicle electrical system 8, particularly in the case of transient regenerative currents during the feed-in processes of actuator 2.The total capacity retained via reserves 12 and 13 can be based on the maximum energy to be absorbed or released on average over time and may include a safety margin in each case.

[0054] In the inventive method, the electrical power input is reduced at the feed-in operating point by using a low feed-in efficiency. With a mechanical power input of 6 kW and a feed-in operating point with an exemplary feed-in efficiency of 16%, the generated electrical power can be reduced to 1 kW, thus reducing the reserve 13 in the energy storage device, since only a smaller amount of energy can be transferred to the energy storage device 3 during the feed-in processes.

[0055] Advantageously, the efficiency in the feed-in processes can be chosen to be as low as possible, so that the reserve 13 for taking stochastic feed-in processes by the actuator 2 can be made as small as possible or even eliminated entirely. This increases the usable capacity of the energy storage device 3, which is available for other functions of the vehicle 1, for example, for recuperation operation of the electric motor 4. Advantageously, the vehicle 1 can thus recuperate more energy during operation and use it for other functions, such as driving via the traction motor 3. In particular, for a vehicle 1 with a hybrid drive, this can reduce CO2 emissions, since the smaller reserve 13, or its elimination, also makes more energy available for operating the electric traction motor 4.Accordingly, the maximum range of a purely electrically powered motor vehicle 1 can be increased.

Claims

[1] Method for operating at least one electromechanical actuator (2) of a motor vehicle (1), wherein the actuator (2) is configured to convert mechanical power into electrical power, which is fed into an energy storage device (3) of the motor vehicle (1) during operation of the motor vehicle (1) in stochastically occurring feed-in processes depending on a feed-in efficiency specified by a feed-in operating point of the actuator (2), wherein the start of a feed-in process is detected by a detection means (10) and at the start of the feed-in process an feed-in operating point of the actuator (2) is set in which the feed-in efficiency is 50% or less. [2] Method according to claim 1, characterized by that at the set feed-in operating point, the feed-in efficiency is 25% or less. [3] Method according to claim 1 or 2, characterized by, that an actuator (2) is used which is designed to convert electrical power into mechanical power during the operation of the motor vehicle (1) in actuator operating processes depending on an operating efficiency specified by an actuator operating point of the actuator (2), wherein in each of the actuator operating processes an actuator operating point is set in which the operating efficiency is 80% or more. [4] Method according to any of the preceding claims, characterized by , that the duration of the feed-in processes generated by the actuator (2) during operation of the motor vehicle (1) is 10 ms or less, in particular 1 ms or less and / or that mechanical power of 1 kW or more can be converted by the actuator (2) in the feed-in processes. [5] Method according to any of the preceding claims, characterized by, that an electromechanical actuator (2) is used which is connected to the energy storage device (3) via a control device (6), wherein the feed-in operating point of the electromechanical actuator (2) is set by controlling the control device (6). [6] Method according to any of the preceding claims, characterized by , that an adaptive damping device, in particular an adaptive suspension damper, is used as the electromechanical actuator (2). [7] Method according to any of the preceding claims, characterized by , that a current measuring device is used as a detection means (10), wherein a current can be measured by the current measuring device which is generated by the actuator (2) during the feed-in process. [8] Method according to any of the preceding claims, characterized by, that when the start of a feed-in process is detected by an actuator control device (15) assigned to the actuator (2), a torque to be set by the actuator (2) is determined, whereby the feed-in operating point is set depending on the determined torque. [9] Motor vehicle comprising at least one electromechanical actuator (2), an energy storage device (3), a detection means (10) and a control device (9), wherein the actuator (2) is configured to convert mechanical power into electrical power, which is fed into the energy storage device (3), during operation of the motor vehicle (1) in stochastically occurring feed-in processes depending on a feed-in efficiency specified by a feed-in operating point of the actuator (2), wherein the start of a feed-in process is detectable by the detection means (10), wherein the control device (9) is configured to carry out a method according to one of the preceding claims. [10] Motor vehicle according to claim 9, characterized by , that the energy storage device (3) is a traction energy storage device and / or that the motor vehicle (1) is a hybrid electric or a fully electric motor vehicle (1).

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