DE102019134966B4 - Method and motor vehicle control system for controlling a longitudinal dynamics of a motor vehicle by specifying a tolerance interval for acceleration or deceleration; and motor vehicle - Google Patents

Abstract

Method for controlling the longitudinal dynamics of a motor vehicle (1), comprising the steps of:- determining a tolerance interval (23) for an acceleration or deceleration of the motor vehicle (1) by a driver assistance module (4),- transmitting the tolerance interval (23) to a control module (3) for the longitudinal dynamics of the motor vehicle (1),- determining different acceleration potentials (9) by the control module (3), wherein the acceleration potentials (9) each have a value for an acceleration or deceleration which can be achieved in a respective predetermined operating state of a drive unit (5) and/or a brake unit (6) of the motor vehicle (1), and- controlling the drive unit (5) and/or the brake unit (6) of the motor vehicle (1) by the control module (3) depending on the tolerance interval (23) and the acceleration potentials (9), so that a resulting acceleration or deceleration of the motor vehicle (1) results within the tolerance interval (23), characterized in that- the acceleration or deceleration of the motor vehicle (1) is controlled by the control module (3) in such a way is controlled such that a predetermined temporal gradient is not exceeded regardless of the transmitted tolerance interval (23), wherein if the driver assistance module specifies a change from deceleration to acceleration during a braking maneuver by means of the tolerance interval (23), only when the dynamic command (28) is transmitted is the deceleration reduced as quickly as possible by appropriately controlling the braking unit by the control module (3) and the acceleration is then controlled such that the predetermined temporal gradient is not exceeded, and/or- the tolerance interval (23) is determined by determining a target value (20) and a minimum value (21, 22) for the acceleration or deceleration, wherein the tolerance interval (23) lies between the target value (20) and the minimum value (21, 22), and wherein during a driving maneuver the target value (20) remains constant in time and the minimum value (21, 22) is shifted in time towards the target value (20) so that the tolerance interval (23) becomes narrower.

Description

The invention relates to a method for controlling longitudinal dynamics of a motor vehicle. A second aspect of the invention relates to a motor vehicle control system for controlling longitudinal dynamics of a motor vehicle according to the method according to the invention. A third aspect of the invention relates to a motor vehicle with the said motor vehicle control system.

Different systems and methods for controlling the longitudinal dynamics of a motor vehicle are known from the state of the art, for example simple cruise control systems for maintaining a predetermined speed or intelligent speed control devices. An intelligent speed control device can, for example, regulate the speed of a motor vehicle depending on other road users. For example, a distance value selected by a user is always maintained or a corresponding distance to the vehicle in front is not exceeded.

An adaptive cruise control system for a motor vehicle with a service brake is, for example, known from EN 10 2008 014 771 A1 known. The adaptive cruise control comprises an electrical control system which is set up to record driving data of the motor vehicle and distance data to a vehicle driving ahead, create a movement prediction from the driving data and the distance data, influence the movement state of the motor vehicle by influencing drive or braking means and output a warning signal to a driver of the motor vehicle if the movement prediction shows that, assuming a predetermined limit deceleration, a collision probability of a collision with another motor vehicle with the adaptive cruise control activated without intervention by a driver of the motor vehicle exceeds a predetermined collision probability threshold value.

The DE 103 35 899 A1 A device for longitudinal guidance of a motor vehicle is known, with a driver assistance system which outputs a braking request signal to a brake control device, wherein the driver assistance system is designed to output a braking request signal in the form of a distance signal which indicates the distance to be covered by the vehicle within which the vehicle is to reach a predetermined target speed, and wherein the brake control device has a conversion unit for converting the distance signal into a brake actuation signal.

Furthermore, the EN 10 2010 030 483 A1 Vehicle controls in which a driver assistance system controls a braking system. The following steps are disclosed: determining an indication of a distance to be covered up to a target point, determining an indication of a speed relating to the distance, and providing the determined information for the distance and the speeds via the vehicle interface for a control unit for controlling the braking system.

The EN 10 2012 013 689 A1 relates to a driver assistance system of a vehicle for controlling a distance of the vehicle from another vehicle. In the method, a distance between the vehicle and the other vehicle and a relative speed between the vehicle and the other vehicle are determined. When the vehicle approaches the other vehicle, the vehicle is operated in an operating state from a group of several predetermined operating states depending on the distance and the relative speed.

The EN 10 2013 016 520 A1 relates to a method for adapting a predicted wheel power of a vehicle for a predeterminable route, wherein a route divided into maneuver classes is specified, the driving behavior of a driver while driving the specified route is evaluated on the basis of an energy consumption predicted for the specified route, it is determined whether a determined deviation represents a relevant deviation in at least one maneuver class driven through on the route, and if a relevant deviation is determined, the predicted wheel power is recalculated.

The EN 10 2018 109 885 A1 relates to a method for cooperatively coordinating future driving maneuvers of a vehicle with external maneuvers of at least one external vehicle, wherein a third-party data packet is received from the external vehicle, in which a third-party trajectory family from an external reference trajectory is contained, a trajectory from a trajectory family for the vehicle is selected as a reference trajectory for the vehicle using the external reference trajectory, wherein a trajectory that is collision-free with the external reference trajectory is selected, the trajectories of the trajectory family are evaluated using boundary trajectories, and at least one cooperation trajectory is selected from the trajectories of the trajectory family using the reference effort value, wherein a data packet with the reference trajectory and the cooperation trajectory is sent to the external vehicle.

From the EN 10 2006 017 176 A1 A speed control device and a motor vehicle with such a speed control device are known.

The EN 10 2008 000 696 A1 discloses a distance and speed controller for motor vehicles.

The EN 10 2013 005 252 A1 describes a hybrid powertrain and a method for controlling the same.

From the EN 10 2016 006 098 A1 A method for controlling a drive train of a hybrid motor vehicle and a device for carrying out the method, in particular in a trike, is known.

A disadvantage of the methods and driver assistance systems described here for controlling the speed of a motor vehicle is that they are not readily suitable for efficient use in a hybrid vehicle, in particular a so-called plug-in hybrid comprising an internal combustion engine and an electric motor, or an electric vehicle which in particular exclusively has one or more electric motors for driving the electric vehicle. Such motor vehicles have an electric drive unit which comprises at least one electric motor which is suitable for braking the motor vehicle in generator mode. In other words, such an electrically operable drive unit can be used to convert kinetic energy of the motor vehicle into electrical energy and thus charge an electrical energy storage device, in particular a so-called traction battery, of the motor vehicle. This is also referred to as recuperation. The recuperated electrical energy which was stored in the electrical energy storage device is then available again to drive the motor vehicle.

In addition to recuperation using the electrically operated drive in generator mode, such motor vehicles also have an additional braking unit, in particular a so-called friction brake. This is necessary due to the limited recuperation power of the electrically operated drive unit, which also limits the deceleration that can be achieved by means of recuperation. In order to optimize energy efficiency, it is therefore advantageous to adapt the automated control of the longitudinal dynamics of the motor vehicle to the special features of a hybrid vehicle or electric vehicle. However, motor vehicles that can only be driven by an internal combustion engine, hydrogen vehicles or motor vehicles with any other type of drive can also benefit from this.

It is therefore an object of the present invention to enable improved energy efficiency when controlling longitudinal dynamics of a motor vehicle.

This object is achieved according to the invention by the subject matter of the independent patent claims. Advantageous embodiments with expedient further developments are the subject matter of the subclaims.

• - Bestimmen eines Toleranzintervalls für eine Beschleunigung oder Verzögerung des Kraftfahrzeugs durch ein Fahrerassistenzmodul,
• - Übermitteln des Toleranzintervalls an ein Steuermodul für die Längsdynamik des Kraftfahrzeugs,
• - Bestimmen unterschiedlicher Beschleunigungspotentiale durch das Steuermodul, wobei die Beschleunigungspotentiale jeweils einen Wert für eine Beschleunigung oder Verzögerung aufweisen, welche in einem jeweils vorbestimmten Betriebszustand einer Antriebseinheit und/oder einer Bremseinheit des Kraftfahrzeugs erreichbar sind, und
• - Ansteuern der Antriebseinheit und/oder der Bremseinheit des Kraftfahrzeugs durch das Steuermodul in Abhängigkeit von dem Toleranzintervall und den Beschleunigungspotentialen, sodass eine resultierende Beschleunigung oder Verzögerung des Kraftfahrzeugs im Rahmen des Toleranzintervalls resultiert.

To solve the above-mentioned problem, the invention proposes a method for controlling longitudinal dynamics of a motor vehicle with the following steps:

• - Determining a tolerance interval for acceleration or deceleration of the motor vehicle by a driver assistance module,
• - Transmission of the tolerance interval to a control module for the longitudinal dynamics of the vehicle,
• - Determining different acceleration potentials by the control module, wherein the acceleration potentials each have a value for an acceleration or deceleration which can be achieved in a respective predetermined operating state of a drive unit and/or a brake unit of the motor vehicle, and
• - Controlling the drive unit and/or the brake unit of the motor vehicle by the control module depending on the tolerance interval and the acceleration potentials, so that a resulting acceleration or deceleration of the motor vehicle results within the tolerance interval.

An acceleration in the sense of the present application is in particular a positive acceleration, i.e. an increase in speed. In other words, the term acceleration in the context of the present application describes in particular exclusively an increase in speed. Analogously, a deceleration is considered to be in particular a negative acceleration. In other words, the term deceleration in the context of the present application describes in particular exclusively a decrease in speed.

The driver assistance module can essentially be an adaptive driving assistant, a cruise control system, a distance control system, a so-called stop-and-go assistant, which is trained to is designed to control a complete stop and restart of the motor vehicle in traffic jam situations, or the like. In concrete examples, the driver assistance module can be the following: adaptive cruise assist (ACA) or adaptive driving assistant, adaptive cruise control (ACC) or adaptive cruise control or distance control cruise control, cruise control system (GRA), speed limiter (LIM) and/or speed assistant (ISA). Direct control of the drive unit and/or the brake unit by the driver assistance module is not possible. The driver assistance module is preferably designed to plan current and future longitudinal dynamics for the motor vehicle. In particular, the motor vehicle plans a current and a future speed for this purpose, in particular a large number of values for a large number of different future points in time.

The driver assistance module can also be designed to plan the lateral dynamics, in particular a movement path, of the motor vehicle. In this case, it can be provided that the driver assistance module controls a control module for the lateral dynamics of the motor vehicle to implement the planned lateral dynamics. The driver assistance module can, for example, specify a yaw rate. The control module for the lateral dynamics can in turn control a steering system, with the control module for the lateral dynamics specifying in particular the steering angle of the steering system. For example, it is provided that the control module for the lateral dynamics derives or calculates the steering angle from the yaw rate.

The tolerance interval for the acceleration or deceleration of the motor vehicle can be determined based on the planned current and/or future speed. For example, the tolerance interval for the acceleration or deceleration of the motor vehicle is selected such that the speed driven by the motor vehicle approaches the planned current and/or future speed. A tolerance range of the tolerance interval can depend on the criticality of a current driving situation or on how quickly or reliably the motor vehicle should or must reach the corresponding planned speed. For example, the tolerance range of the tolerance interval can be smaller in critical driving situations than in less critical driving situations. For this purpose, a criticality level can be determined by the driver assistance module, for example. For example, the tolerance range of the tolerance interval can approach zero if a collision of the motor vehicle, for example with another road user, is imminent. In this case, tolerance when decelerating or when the motor vehicle brakes hard is not possible. For example, the tolerance interval can be chosen to be very wide if it is possible to brake the vehicle more slowly without danger or if the vehicle is to be accelerated in a non-time-critical manner after passing a town sign when leaving a town. In other words, the tolerance interval can have a reduced tolerance range as the criticality of the driving situation increases.

The driver assistance module can take different data into account when determining or planning the current and/or future speed. For example, when planning the speed, the driver assistance module can take into account navigation data, map data, gradient data, which are part of the map data and indicate a current and/or future gradient of sections of the route to be traveled, a gradient measured by the motor vehicle's sensors, sensor data from an environmental sensor system or the like. The sensor data from the environmental sensor system can map an environment of the motor vehicle or describe or indicate objects detected therein as well as free road areas. For example, such an environmental sensor system can include one or more cameras, one or more radar sensors, one or more lidar sensors, one or more ultrasonic sensors or the like. A combination of different sensors is also possible and even advantageous. The criticality level can also be determined based on the data mentioned here as an example. The criticality level can be determined internally by the driver assistance module or received from another module, for example via accident prediction.

The control module of the motor vehicle is advantageously designed to directly control the drive unit and/or the brake unit of the motor vehicle. In other words, the control module can be designed to output a specific brake pressure, a specific brake intensity or any measure that characterizes the intensity of a deceleration by the brake unit to the brake unit. The brake unit can, for example, comprise one or more friction brakes, preferably disc brakes, one or more drum brakes and/or one or more eddy current brakes. In advantageous embodiments, the brake unit comprises a respective friction brake, in particular comprising a respective brake caliper and a respective brake disc, on each wheel of the motor vehicle.

The drive unit can, for example, have one or more motors for driving the motor vehicle. Due to friction within the motor, resulting drag torques and/or recuperation in generator mode of an electrically operated drive or electric motor, a certain deceleration of the motor vehicle can also be achieved in some embodiments by means of the drive unit.

The drive unit can, for example, comprise an internal combustion engine, one or more electric motors, a fuel cell or the like. In some embodiments, the motor vehicle is a motor vehicle with an internal combustion engine. In this case, the drive unit can, for example, comprise an internal combustion engine and a transmission. In some embodiments, the motor vehicle is a so-called battery-electric motor vehicle, in which case the drive unit can have one or more electric motors. In the case of a hydrogen vehicle or fuel cell vehicle, the drive unit can comprise a fuel cell and one or more electric motors.

In the example of a hybrid vehicle, the drive unit can comprise an internal combustion engine and one or more electric motors. The internal combustion engine and the electric motor or the electric motors can equally be designed to directly drive the motor vehicle, i.e. in particular to generate a wheel torque on at least one wheel of the motor vehicle. The different drives can drive different wheels of the motor vehicle or at least partially the same wheels. In this case, the hybrid drive is a so-called parallel hybrid drive. In the case of a serial hybrid, only the electric motor or the electric motors are designed to drive the motor vehicle or to generate a wheel torque on a wheel of the motor vehicle. In this case, however, the internal combustion engine is designed to drive only a generator to provide electrical energy. This electrical energy can then be used to charge a buffer battery or an electrical battery storage unit of the motor vehicle to supply the electric motor or the electric motors. This is similar with a fuel cell vehicle, in which a corresponding electrical energy storage unit or a corresponding buffer battery is charged by means of the fuel cell.

The control module, also referred to as a “vehicle motion manager” (VMM), is designed in particular to directly control the drive unit with regard to driving the motor vehicle or propelling the motor vehicle using appropriate control commands. For example, the control module can command the drive unit to output a torque determined by the control module, to operate at a speed determined by the control module, to select one or more of the different motors, and the like. For example, in the case of several electric motors, the control module can specify which respective torque the electric motors should generate. In the case of a hybrid vehicle, the control module can specify whether the combustion engine should be started or stopped, and which respective torque should be generated by the combustion engine and the individual electric motors or the electric motor. In a purely electric operating mode, for example, it can be provided that the combustion engine is in a switched-off state and that the motor vehicle is driven exclusively by the electric motors or the electric motor. In the case of a conventional vehicle with a combustion engine, the control module can, for example, specify a particular gear of the transmission, specify whether to shift up or down the gear, or the like. This can also be done in a similar way with a parallel hybrid drive.

Alternatively or additionally, it can be provided that the control module does not control the drive unit and/or the brake unit directly, but rather collects and/or consolidates respective requirements from the driver assistance module, from other driver assistance modules for other functionalities and/or from control elements for the driver, for example accelerator pedal, brake pedal, switching elements for changing gear and/or steering wheel. An operating strategy module can then be present downstream of the control module, which distributes the required wheel torques to individual motors of the drive unit and/or brakes of the brake unit. The operating strategy module can be designed to decide whether the combustion engine or an electric motor should be used.

The control module determines the different acceleration potentials for different operating states of the drive unit and/or the brake unit of the motor vehicle. Example operating states are set out below. The acceleration potential is the acceleration or deceleration of the motor vehicle that results in the respective predetermined operating state of the drive unit and/or the brake unit. For example, the Acceleration potentials depend on the wheel torques generated on the wheels of the motor vehicle by the drive unit and/or brake unit in the respective operating state. In addition, the acceleration potentials can depend on a mass of the motor vehicle, a rolling resistance of the motor vehicle and a driving resistance of the motor vehicle. Alternatively or additionally, the acceleration potentials can each depend on the gradient of a route currently traveled by the motor vehicle. Accordingly, the motor vehicle can, for example, have respective sensors for determining the current mass of the motor vehicle and/or for determining the rolling resistance and/or air resistance in a current driving situation. Alternatively or additionally, the motor vehicle can have a sensor for determining the gradient of the road currently traveled by the motor vehicle. These exemplary quantities can be evaluated together with the respective operating state of the drive unit and/or the brake unit to determine the acceleration potentials.

A gradient determination to determine the gradient uses, for example: a longitudinal acceleration sensor, a derivative of the vehicle speed (acceleration above ground) and/or gradient compensation with the information from height sensors on the wheels, an air pressure sensor and GPS altitude values. The mass estimation to determine the mass of the motor vehicle uses, for example, various mathematical approaches to calculate a value for the mass using vehicle acceleration, gradient and drive torque. A friction coefficient determination uses, for example, the value of a friction coefficient estimator using information from a wetness sensor and slip controller. A friction coefficient determined in this way can indicate which wheel torque for acceleration and/or deceleration enables a momentary frictional connection between the wheels or tires and the road. A maximum value for the slip can be predetermined, which is not exceeded when the wheel torque for acceleration and/or deceleration is transmitted. The wheel torque at which the predetermined value for the slip is reached can therefore be determined.

The control module then controls the drive unit and/or the brake unit of the motor vehicle depending on the tolerance interval and the acceleration potentials. The control is carried out in such a way that a resulting acceleration or deceleration of the motor vehicle results within the tolerance interval. In other words, by determining the tolerance interval, the control module is given the option of additionally setting or specifying the resulting acceleration or deceleration of the motor vehicle depending on the acceleration potentials. In particular, based on the acceleration potentials, it can be determined for which of the respective predetermined operating states of the drive unit and/or the brake unit a resulting acceleration within the tolerance interval is possible. For example, an operating state whose acceleration potential is within the tolerance interval can be selected from the respective operating states for acceleration and/or deceleration. The tolerance range of the tolerance interval can therefore potentially be used to select a specific operating state from different operating states that are within the tolerance interval. For example, a predetermined selection criterion can be used for this purpose. For example, according to the predetermined selection criteria, the most economical operating mode can be selected from the operating modes whose respective acceleration potential lies within the tolerance range. Which operating mode is the most economical depends on the respective motor vehicle and its respective drive unit. A predetermined ranking of the operating modes in terms of their economic efficiency can be stored in the control module, for example. When selecting the most economical operating mode, the selection can then be made according to the predetermined ranking.

In an electric operating mode of a hybrid vehicle, in particular with a parallel hybrid drive in which the motor vehicle is driven exclusively by one or more electric motors, acceleration potentials for purely electric acceleration and acceleration with the electric motor or motors with the aid of the combustion engine can be determined for an acceleration planned by the driver assistance module. If both acceleration potentials are now within the tolerance interval, the drive unit can select the operating state associated with the acceleration potentials with which the acceleration is carried out in accordance with the predetermined selection criterion. The predetermined selection criterion can include that purely electric acceleration is preferable.

This results in a functional separation between the driver assistance module and the control module. In particular, the driver assistance module and the control module can be developed separately to reduce their respective complexity. By specifying the acceleration by the driver assistance module using the tolerance interval and determining the different acceleration potentials for the respective operating states, a high degree of flexibility can still be achieved. Both the driver assistance module and the control module can be operated within the respective reasonable limits. Due to the tolerance with regard to acceleration or deceleration, the present method enables a flexible selection of the operating state for the drive unit and/or the brake unit within the permissible and reasonable limits for planning the driver assistance module. The complexity of the driver assistance module is reduced by the fact that it does not have to make any decisions regarding the drive unit and/or the brake unit of the motor vehicle. The same driver assistance module can therefore be used flexibly for different types of drive, for example conventional motor vehicles with combustion engines, electric vehicles, hybrid vehicles or hydrogen vehicles or fuel cell vehicles. The respective specifics of the different drives therefore only necessarily have to be implemented in the control module. However, the flexibility using the tolerance interval still ensures that the control module operates in a way that is advantageous for the respective drive.

According to a second embodiment of the invention, it is provided that the tolerance interval is determined by determining a target value and a minimum value for the acceleration or deceleration, with the tolerance interval lying between the target value and the minimum value. In other words, the tolerance interval is defined or set by the target value and the minimum value for the acceleration or deceleration. The target value or minimum value for the acceleration or deceleration is to be seen in particular in terms of amount. In particular, it is provided that the target value is always greater in terms of amount than the minimum value. In the case of acceleration, the target value indicates a greater acceleration or speed increase than the minimum value. In the case of deceleration, the target value indicates a greater decrease in speed or deceleration than the minimum value. The tolerance interval is thus used to output which acceleration or deceleration best fits the planning by the driver assistance module and which acceleration or deceleration is minimally required by the driver assistance module. Within these limits, the control module can select the operating state, with the predetermined selection criterion being applied in particular. According to the predetermined selection criterion, it can be specified that the drive unit and/or the brake unit are controlled in such a way that a resulting acceleration or deceleration of the motor vehicle results in accordance with the target value, unless a more economical operating state with which this cannot be achieved also lies within the tolerance interval with its acceleration potential. In this case, the more economical operating state is to be preferred to the operating state in which the target value is achieved. In this way, the requirements of the driver assistance module for acceleration or deceleration are even better documented.

Furthermore, according to the second embodiment, it is provided that during a driving maneuver the target value remains constant over time and the minimum value is shifted over time in the direction of the target value, so that the tolerance interval becomes narrower. In other words, the tolerance width of the tolerance interval becomes narrower during a driving maneuver or the same driving maneuver over time. This is done in particular by shifting the minimum value in the direction of the target value over time. A deviation from the target value trained by the tolerance interval thus becomes smaller over time. This is particularly advantageous in order to enable a high degree of flexibility when setting the operating state on the one hand, but also to ensure that the speed of the motor vehicle approaches the planned speed as quickly as possible.

According to a third embodiment of the invention, it is provided that the drive unit comprises an electric motor and an internal combustion engine and the tolerance interval is determined in such a way that it has a sufficient tolerance range during an acceleration maneuver to avoid switching on the internal combustion engine. In other words, the tolerance interval is determined with a sufficient tolerance range so that even without switching on the internal combustion engine, an acceleration of the motor vehicle results within the tolerance interval. Whether this is the case can initially be verified by the control module based on the acceleration potential for the corresponding operating state and the tolerance interval. This is particularly advantageous if the target value is above the maximum acceleration potential of the electrically operated drive unit. In this case, if only the target value is transmitted without a tolerance interval, the internal combustion engine would definitely be switched on in order to meet the target value for the acceleration. Due to the tolerance interval, it is possible within the scope of the present application to switch on the internal combustion engine. energizing motor if the acceleration potential for the predetermined operating state of maximum acceleration by the electrically operated drive unit only lies within the tolerance interval.

In the third embodiment, it is additionally provided that only in the case of the additional transmission of a dynamic command from the driver assistance module to the control module is the acceleration or deceleration of the motor vehicle controlled by the control module in such a way that the predetermined temporal gradient is exceeded if the tolerance range specifies a corresponding acceleration or deceleration. In other words, by transmitting the dynamic command by the driver assistance module, compliance with the acceleration or deceleration transmitted by the tolerance range can be enforced, even if the predetermined temporal gradient is thereby exceeded. This is advantageous, for example, if emergency braking is to be triggered. In this case, stopping the gradient would result in the torque of the drive unit on the wheels of the motor vehicle being reduced only slowly, in accordance with the predetermined temporal gradient, even though the need for emergency braking has already been recognized.

According to a further development, in addition to the respective operating state of the drive unit and/or the brake unit, one or more of the following variables are also taken into account for determining the acceleration potential: the mass of the motor vehicle, the gradient of the road currently being driven on, the driving resistance, in particular the rolling resistance and/or the air resistance, and/or route data or map data from the navigation system. The mass, the gradient and the driving resistance, in particular the rolling resistance and/or the air resistance, can be recorded or determined by means of a respective sensor system of the motor vehicle. The navigation system can be part of the motor vehicle. In particular, the map data or the route data can be stored in a storage unit, for example a hard disk, a flash memory, an optical storage medium or the like, inside the motor vehicle or can be retrieved from the Internet via a data connection. These variables are particularly advantageous in order to be able to convert respective torques or wheel torques, which can occur in the respective predetermined operating states, into the achievable acceleration. The gradient of the currently drivable road can be extracted from the route data or map data as an alternative or in addition to its detection using the corresponding sensors. In this case, the gradient can also be determined predictively for the future to determine the acceleration potential.

According to a further development, it is provided that at least one of the following operating scenarios is taken into account by the predetermined operating conditions: maximum acceleration by all drive units (in particular in a hybrid vehicle), maximum acceleration only by one or all electrically operated drive units or electric motors, maximum acceleration without gear changes in the transmission of the motor vehicle (in particular in a motor vehicle with a combustion engine), deceleration in coasting mode (in particular due to driving resistance, in particular rolling resistance and/or air resistance), maximum deceleration solely due to drag losses and/or due to recuperation, maximum deceleration due to recuperation. Thus, respective acceleration potentials must be determined for different operating scenarios. Based on these acceleration potentials and the tolerance interval, the control module can then select which operating conditions are best suited according to the predetermined selection criterion in order to achieve the resulting acceleration or deceleration of the motor vehicle within the tolerance interval. In this case, in accordance with the predetermined selection criterion, in particular the most economical operating mode can be selected from the operating modes whose respective acceleration potential lies within the tolerance range. By taking the corresponding operating scenarios into account, particularly economical operation of the motor vehicle can be ensured. The acceleration potential, which indicates the maximum deceleration through recuperation, can take into account how long the corresponding recuperation performance can be maintained. As the electric motor, energy storage device or power cables heat up, the recuperation performance can drop over time. In particular, it is provided that the acceleration potential, which indicates the maximum deceleration through recuperation, can be maintained at least for a predetermined period of time, advantageously 10 seconds. In other words, the acceleration potential indicates which maximum deceleration can be maintained for at least the predetermined period of time, advantageously 10 seconds, through recuperation (without friction brake).

Another possible acceleration potential is a so-called comfort potential. The comfort potential can indicate an acceleration that, if exceeded, leads to a loss of comfort. This can, for example, be due to high engine speeds. numbers or unfavorable load requirements with noise emissions. When controlling the drive unit depending on the tolerance interval and the acceleration potential, such losses in comfort can be avoided by not exceeding the comfort potential if this is within the tolerance interval.

Another acceleration potential or two other acceleration potentials is/are a respective friction coefficient potential for the acceleration and/or deceleration of the motor vehicle. For this purpose, for example, a value from the friction coefficient determination described above can be used. A friction coefficient potential for the acceleration and/or a friction coefficient potential for the deceleration can therefore be determined. The respective friction coefficient potential can indicate which acceleration or deceleration (maximum) is possible without exceeding the predetermined value for the slip.

Based on the friction coefficient and a dynamic axle load distribution, the friction coefficient potential for acceleration can indicate which acceleration is possible without traction control. This is intended to adapt the requirements of the driver assistance systems to the ambient conditions. There should be no unnecessary function shutdowns due to interventions by the traction control.

The friction coefficient potential for deceleration can indicate what deceleration is possible based on the friction coefficient and the dynamic axle load distribution. With this information, the driver assistance system can proactively drive more defensively or brake earlier.

According to a further development, the different acceleration potentials are transmitted by the control module to the driver assistance module. In other words, in this case, the previously determined different acceleration potentials are not used solely within the control module to select the respective operating state for the drive unit and/or the brake unit. Instead, the acceleration potentials can be transmitted to the driver assistance module in this case. This means that the acceleration potentials can be taken into account for future planning of the acceleration and/or the speed by the driver assistance module.

According to a further development, it is provided that the acceleration potentials transmitted to the driver assistance module are taken into account for subsequent planning of a further tolerance interval. By taking the different acceleration potentials into account when planning the future speed and/or acceleration, a further tolerance interval for a later point in time or period can be determined based on the transmitted acceleration potentials. This can further improve positive feedback through communication between the driver assistance module and the control module.

According to a further development, the tolerance interval is determined in such a way that when a non-safety-critical braking maneuver is initiated, it increases sufficiently slowly to higher deceleration values in order to avoid an intervention by the braking unit, in particular a friction brake, before the end of load impact damping on the drive unit. A braking maneuver whose criticality does not exceed a predetermined level can be referred to as a non-critical or non-safety-critical braking maneuver. This tolerance interval can in particular ensure that the friction brake is used to decelerate the motor vehicle, although the drive unit would be able to decelerate the motor vehicle sufficiently through its drag torque or through recuperation in the case of an electric motor. However, such a deceleration by means of the drive unit requires a certain amount of lead time in order to carry out the load impact damping. As part of the load impact damping, a drive torque is first reduced before the drive unit switches to drag mode. This is necessary in order to avoid mechanical overload and/or loss of comfort due to a load impact. If the driver assistance module were to transmit only its target value without the tolerance interval, the time during which the load impact damping is carried out would have to be bridged using the brake unit, in particular the friction brake, due to the real-time capability of the process. However, this leads to unnecessary brake wear and losses of kinetic energy, which can no longer be used for recuperation. This is particularly exacerbated by the fact that after a short braking intervention using the friction brake, a drag torque continues to be present for a longer period of time, even if it has already been released. For this reason, it is particularly advantageous to avoid using the brake unit, in particular the friction brake.

According to a further development, it is provided that the acceleration or deceleration of the motor vehicle is controlled by the control module in such a way that a predetermined temporal gradient is independent of the transmitted tole tolerance interval is not exceeded. In other words, the predetermined temporal gradient specifies the maximum gradient for the acceleration or deceleration in the time axis. In other words, the acceleration or deceleration of the motor vehicle is controlled in such a way that the resulting acceleration or deceleration does not exceed the predetermined temporal gradient or is not greater than the predetermined temporal gradient. This also applies if a larger gradient in the acceleration or deceleration would have to be specified according to the tolerance interval. In the event that the gradient of the acceleration or deceleration transmitted by means of the tolerance interval exceeds the predetermined temporal gradient, the transmitted tolerance interval is therefore ignored insofar as the amount of acceleration or deceleration is limited by the predetermined temporal gradient. In this way, driving comfort can be improved and the ISO standard 22179 can also be complied with. On the other hand, the complexity of the system consisting of the control module and the driver assistance module can be further reduced, since such functions only have to be taken into account in the control module and not in the driver assistance module.

According to another example, if the driver assistance module specifies a change from deceleration to acceleration during a braking maneuver using the tolerance interval, only when the dynamic command is transmitted is the deceleration reduced as quickly as possible by appropriately controlling the braking unit by the control module and then the acceleration is controlled in such a way that the predetermined temporal gradient is not exceeded. In other words, in the example mentioned, the predetermined gradient is only exceeded (in terms of amount) when the wheel torque is reduced to decelerate the motor vehicle. When the wheel torque used for acceleration is subsequently built up by appropriately controlling the drive unit, the predetermined gradient is not exceeded or maintained. In this way, it can be ensured that the braking unit, which destroys drive energy, is released as quickly as possible or is transferred to an idle mode in order to save drive energy. In this way, drive energy can be saved when the motor vehicle is operated.

A further aspect of the invention relates to a motor vehicle control system for controlling longitudinal dynamics of a motor vehicle with a driver assistance module and a control module. The motor vehicle control system is designed to carry out the method according to the invention. The motor vehicle control system has at least one processor device that is designed to carry out an embodiment of the method according to the invention. For this purpose, the processor device can have at least one microprocessor and/or at least one microcontroller and/or at least one FPGA (Field Programmable Gate Array) and/or at least one DSP (Digital Signal Processor). Furthermore, the processor device can have program code that is designed to carry out the embodiment of the method according to the invention when executed by the processor device. The program code can be stored in a data memory of the processor device. In a further embodiment, the motor vehicle control system can have two such processor devices, with the driver assistance module being provided by a first of the two processor devices and the control module being provided by the second of the two processor devices. The method steps that are carried out by the driver assistance module or the control module can then be carried out in particular by the respective processor device.

The invention also relates to a motor vehicle with a motor vehicle control system of the above-mentioned type.

The motor vehicle according to the invention is preferably designed as a motor vehicle, in particular as a passenger car or truck, or as a passenger bus or motorcycle.

The invention also includes further developments of the motor vehicle according to the invention and of the motor vehicle control system, which have features as have already been described in connection with the further developments of the method according to the invention. For this reason, the corresponding further developments of the motor vehicle according to the invention and of the motor vehicle control system are not described again here.

The invention also includes combinations of the features of the described embodiments.

• 1 in einer äußerst schematischen Seitenansicht ein Kraftfahrzeug mit einem Fahrerassistenzmodul und einem Steuermodul zum Steuern einer Längsdynamik;
• 2 bis 7 unterschiedliche zeitliche Verläufe in der Regelung beziehungsweise Steuerung unterschiedlicher Größen bezüglich der Längsdynamik des Kraftfahrzeugs; und
• 8 ein Blockschaltbild einer beispielhaften Ausführungsform eines Kraftfahrzeug-Steuersystem s.

Exemplary embodiments of the invention are described below.

• 1 in a highly schematic side view of a motor vehicle with a driver assistance module and a control module for controlling longitudinal dynamics;
• 2 to 7 different time courses in the regulation or control different sizes regarding the longitudinal dynamics of the vehicle; and
• 8th a block diagram of an exemplary embodiment of a motor vehicle control system.

The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the components of the embodiments described each represent individual features of the invention that are to be considered independently of one another and which also develop the invention independently of one another. Therefore, the disclosure should also include combinations of the features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by other features of the invention already described.

In the figures, identical reference symbols designate functionally identical elements.

1 shows a motor vehicle 1 with a driver assistance module 4 and a control module 3. The driver assistance module 4 is designed to control or regulate a speed of the motor vehicle 1. In particular, the driver assistance module 4 can control or regulate the speed of the motor vehicle 1 according to a user input and/or a route of a route traveled by the motor vehicle 1 and/or other road users. For example, the driver assistance module 4 can plan the speed of the motor vehicle 1 in such a way that a predetermined or driver-specified minimum distance to a motor vehicle driving ahead is not undercut. Alternatively or additionally, it can be provided that the driver assistance module 4 attempts to maintain a speed specified by the driver. To detect other road users, in particular the motor vehicle driving ahead, the motor vehicle 1 can have a sensor unit 14. The driver assistance module 4 can therefore be designed to detect corresponding environmental data from the sensor unit 14. The sensor unit 14 can have one or more of the following sensors: camera, 3D camera, radar sensor, lidar sensor, ultrasonic sensor, infrared sensor and the like. In particular, several sensors with different and/or the same detection principle can be combined.

The driver assistance module 4 is accordingly designed to plan the speed of the motor vehicle 1 in advance. In particular, the driver assistance module 4 plans a current value for the speed of the motor vehicle 1 as well as a respective speed value for a large number of future points in time. In order to achieve the planned speeds for the current point in time or the future points in time, the driver assistance module 4 can determine or calculate a necessary acceleration.

The control module 3 is designed to directly control the longitudinal dynamics of the motor vehicle 1 by directly controlling a drive unit 5 and/or a brake unit 6 of the motor vehicle 1. For example, the control module 3 specifies a respective operating state for the drive unit 5 and/or the brake unit 6. For example, the control module 3 can be designed to command the drive unit 5 to output a torque determined by the control module 3. Similarly, the control module 3 can be designed to command the brake unit 6 to apply a certain braking force.

In the present example, the brake unit 6 comprises a respective friction brake on each wheel of the motor vehicle 1. The drive unit 5 comprises an electric motor 12 and an internal combustion engine 13. The internal combustion engine 13 can be a gasoline engine or a diesel engine. The electric motor 12 is in particular an electrical machine, preferably a synchronous machine or an asynchronous machine. An electrical energy store 10, in particular a so-called traction battery or a so-called high-voltage storage device, for example a lithium-ion battery, is designed to supply the drive unit 5, in particular the electric motor 12, with electrical energy to drive the motor vehicle 1. Alternatively or additionally, the electric motor 12 can be designed to convert kinetic energy of the motor vehicle 1 into electrical energy in a generator mode and to store this in the electrical energy store 10. The motor vehicle 1 is braked by this conversion of kinetic energy. This process is also referred to as recuperation.

According to the drive unit 5, the motor vehicle 1 is a so-called hybrid vehicle. In the present hybrid vehicle, also called parallel drive, acceleration or propulsion of the motor vehicle 1 is possible only by the internal combustion engine 13, only by the electric motor 12 or simultaneously by the electric motor 12 and the internal combustion engine 13. Accordingly, the control module 3 is designed to control the use of the two motors 12, 13 or to specify which of the two motors 12, 13 is used and to what extent to accelerate the motor vehicle 1. For example, it is sensible to drive the motor vehicle 1 purely electrically, i.e. to accelerate only with the aid of the electric motor 12, while the motor vehicle 1 is driving through a city or when particularly economical operation of the motor vehicle 1 is desired. It can be particularly advantageous to drive the motor vehicle 1 exclusively with the combustion engine 13 if the charge of the electrical energy storage device 10 is to be saved for a later locally emission-free journey, for example through a city. The simultaneous operation of both motors 12, 13 is sensible when maximum power and/or economical operation over a longer distance is required. A longer distance is referred to in particular as a distance which, due to the capacity of the electrical energy storage device 10, cannot be managed purely electrically without recharging the electrical energy storage device 10 in between.

The driver assistance module 4 transmits the planned acceleration or the acceleration value required to reach or maintain the planned speed to the control module 3. The control module 3 controls the drive unit 5 and/or the brake unit 6 accordingly. In order to increase the flexibility for controlling the drive unit 5 and/or the brake unit 6 by the control module 3, the driver assistance module 4 transmits a tolerance interval 23 for the acceleration and/or deceleration of the motor vehicle 1 to the control module 3. In other words, the driver assistance module 4 does not transmit a single value for the acceleration or deceleration, which must then be adhered to exactly, but the tolerance interval 23 gives the control module 3 a certain degree of flexibility in order to optimize operation with regard to the drive unit 5 and/or brake unit 6.

For this purpose, the control module 3 determines different acceleration potentials 9. The individual acceleration potentials 9 will be discussed in more detail below. The control module 3 then controls the drive unit 5 and/or the brake unit 6 depending on both the tolerance interval 23 and the acceleration potentials 9. The control is carried out depending on the two variables mentioned in such a way that a resulting acceleration or deceleration 26 of the motor vehicle 1 results within the tolerance interval 23. In other words, the drive unit 5 and/or the brake unit 6 is controlled in such a way that the motor vehicle 1 is accelerated or decelerated with a value for the acceleration or deceleration that lies within the tolerance interval 23.

The acceleration potentials 9 can be derived from respective torques which can be transmitted to the motor vehicle 1 in the respective predetermined operating state for which an acceleration potential is determined. In particular, a wheel torque generated on the wheels of the motor vehicle 1 in the respective operating state is to be taken into account. Alternatively, an output torque of the drive unit 5, a drag torque in a coasting operation of the drive unit 5 and/or a torque which must be applied to generate recuperation power in the drive unit 5 can be evaluated to determine the acceleration potentials. In this case, too, a possible torque in the respective operating state can of course be taken into account. In the case of the brake unit 6, an acceleration potential can be derived from a braking force applied to the brake caliper. In addition, however, other variables are advantageously used to determine the acceleration potentials. For example, to convert the respective torques or wheel torques, a constant weight of the motor vehicle corresponding to a predetermined weight value on a level road surface can be assumed. In a further embodiment, a measuring device 7 of the motor vehicle 1 can provide further variables for determining the acceleration potentials. Such variables can be, for example, one or more of the following: currently measured vehicle mass of the motor vehicle 1, driving resistance, in particular rolling resistance and/or air resistance, according to a gradient of a road currently being traveled on and the like. Additionally or alternatively, the gradient can be retrieved from a navigation system of the motor vehicle 1. In this case, a predictive determination of the gradient can also be made possible. The acceleration potentials 9 can thus also be predicted for the future. In a further embodiment, the course of the road can also be retrieved from the navigation system and used to determine the acceleration potentials 9.

8th shows in an exemplary block diagram the interaction of the measuring device 7, the control module 3 and the driver assistance module 4.

The above-mentioned variables, for example the vehicle mass, the driving resistance, the gradient and the variables from the navigation system, can be provided from the measuring device 7 to the control module 3 and/or the driver assistance module 4 by means of corresponding data packets 19. It can also be provided that the predictive variables, for example variables from the navigation system, only be provided to the driver assistance module 4. In some embodiments, it is provided that only the driver assistance module 4 plans the movement of the motor vehicle for the future, but not the control module 3. The control module 3 can transmit the determined acceleration potentials 9 to the driver assistance module 4. The driver assistance module 4 in turn transmits the tolerance interval 23 to the control module 3.

Possible operating states for which a respective acceleration potential 9 is determined are, for example, maximum acceleration with motors 12, 13 of the drive unit 5, whereby a kickdown, i.e. downshifting, can also be provided, comfortable acceleration, in which the motors 12, 13 are not set to full load, for example no kickdown is provided and/or the respective motor 12, 13 is revved up to a lower speed than for maximum acceleration, and maximum acceleration exclusively with electrically operated motors, i.e. in this case the electric motor 12, without support from the combustion engine 13. These examples of the acceleration potential 9 can be considered acceleration-effective potentials, since the motor vehicle is accelerated in all three operating states, i.e. its speed increases. However, acceleration potentials 9 can also be determined for operating states in which the motor vehicle 1 is decelerated or the speed of the motor vehicle 1 decreases. Examples of acceleration potentials 9 in this regard are: deceleration in coasting mode when the wheels are almost free of wheel torque (for example when the motors 12, 13 are disengaged), deceleration of the motor vehicle 1 in coasting mode, i.e. when the motors 12, 13 are engaged, for example, when idling (in this case, the coasting cut-off can cause a drag torque to be exerted on the motor vehicle 1 by the respective motor 12, 13, in particular the combustion engine 13), and a maximum recuperation potential 33, which indicates the maximum deceleration of the motor vehicle 1 through recuperation with the electric motor 12 in generator mode. Since the acceleration potentials 9 can shift depending on the condition of the road, in particular the gradient, they are advantageously also determined as a function of the gradient, which is retrieved as part of the data 19 from the measuring device 7. In coasting mode, the gradient can also result in acceleration if the acceleration due to the downhill drive exceeds the driving resistance. This can be taken into account here.

Different operating states are described below as examples: 2 and 3 represent an acceleration of the motor vehicle 1. The t-axis is the time axis and the a-axis the acceleration axis. Positive values on the acceleration axis a represent an acceleration, negative values a deceleration. 2 and 3 the driver assistance module 4 is activated at a time 39. Its predictive planning of the speed makes it necessary for the motor vehicle 1 to accelerate. The driver assistance module 4 therefore outputs a target value 20 for the acceleration. To achieve the greatest possible flexibility, the driver assistance module 4 also outputs a minimum value 21 for the acceleration. The tolerance interval 23 lies between the target value 20 and the minimum value 21. The control module 3 is therefore able to set the acceleration of the motor vehicle 1 according to a value within the tolerance interval 23.

In the present example, two acceleration potentials 9 are determined by the control module 3: An acceleration potential 30, which represents the maximum possible acceleration of the motor vehicle 1 when the maximum drive power is applied by the drive unit 5. An electrical acceleration potential 31 represents a maximum acceleration of the motor vehicle 1 using only the electric motor 12.

This is less than the maximum acceleration potential 30, since the drive power of the combustion engine 13 is not used in this case. From the acceleration potentials 30, 31 and the tolerance interval 23, i.e. in particular the target value 20 and the minimum value 21, the control module 3 determines an internal target value 25 for the acceleration of the motor vehicle 1. This target value 25 increases in accordance with a maximum temporal gradient. In other words, the control module 3 determines the internal target acceleration 25 in such a way that it does not exceed the predetermined temporal gradient. This is provided for reasons of comfort and standardized regulations, such as the ISO standard 22179.

The difference between the two figures is that the tolerance interval 23 is so wide that the electrical acceleration potential 31 lies within the tolerance interval 23. It is therefore possible, on the one hand, to accelerate the motor vehicle 1 with the target value 20 using both motors 12, 13. Alternatively, in accordance with the tolerance interval 23, it is also possible to accelerate the motor vehicle purely electrically using the electric motor 12. Since this is the more economical operating state, it can be provided that this is to be preferred by the control module 3. The control module 3 thus controls the drive unit 5 in such a way that the real acceleration 26 is set in the range of the electrical acceleration potential 31. In 3 however, the minimum value 21 for the acceleration is above the electrical acceleration potential 31. A purely electrical acceleration of the motor vehicle 1 is therefore not possible, since a purely electrical acceleration would lie outside the tolerance interval 23. The control module 3 accordingly selects both motors 12, 13 to accelerate the motor vehicle 1. The actual acceleration 26 results within the tolerance interval 23 through the corresponding control of the drive unit 5 by the control module 3.

The 4 , 5 and 6 show a deceleration of the motor vehicle 1. In the driving situation according to 4 only a low criticality level for the deceleration is determined by the driver assistance module 4. The criticality level is determined, for example, based on the sensor data from the sensor unit 14. In particular, the criticality level in the driving situation is according to 4 less than a predetermined threshold. This also applies to 5 . In the driving situation according to 6 However, a high level of criticality is determined, in particular the criticality level is higher than the predetermined threshold. For example, a rapid braking maneuver in the driving situation according to 6 necessary to avoid a collision with another road user, for example rear-ending someone while they are braking to turn.

In addition to the acceleration potentials 30, 31, a thrust potential 32 is determined here as an acceleration potential 9. The thrust potential 32 represents an operating state in which the motor vehicle 1 is decelerated by a drag torque of the drive unit 5, in particular of the combustion engine 13. Recuperation by the electric motor 12 is not provided in the operating state of the thrust potential 32. In addition, a recuperation potential 33 is determined as an acceleration potential 9. The recuperation potential 33 represents an operating state in which maximum recuperation occurs by the electric motor 12. In other words, the recuperation potential 33 represents the maximum deceleration by the electric motor 12 in its generator mode. The recuperation potential 33 advantageously indicates which maximum deceleration can be maintained for at least a predetermined period of time, advantageously 10 seconds, solely by recuperation (without friction brake).

Another possible acceleration potential 9 is a so-called comfort potential. The comfort potential can indicate an acceleration which, if exceeded, leads to a loss of comfort. Another acceleration potential, or two further acceleration potentials, is/are a respective friction coefficient potential for the acceleration and/or the deceleration of the motor vehicle 1. For this purpose, for example, a value from a friction coefficient determination between motor vehicle 1 and the road can be used. A friction coefficient potential for the acceleration and/or a friction coefficient potential for the deceleration can therefore be determined. The respective friction coefficient potential can indicate which acceleration or deceleration (maximum) is possible without exceeding a predetermined value for the slip.

In the 4 , 5 and 6 In addition to the target value 20, a minimum value 22 for the deceleration is transmitted by the driver assistance module 4 to the control module 3. The minimum value 22 for the deceleration can also extend into the positive range of the acceleration axis A in order to avoid an erroneous intervention of the friction brake. Due to the safety-critical braking in the driving situation according to 6 the minimum value 22 here corresponds to the target value 20. In other words, the tolerance range of the tolerance interval 23 in the driving situation corresponds to 6 the value 0. No tolerance is allowed.

During non-critical braking manoeuvres according to the 4 and 5 a tolerance interval 23 is formed between the target value 20 and the minimum value 22. The tolerance width of the tolerance interval 23 is selected such that sufficient time remains for load impact damping 29. As part of the load impact damping 29, the drive unit 5 is slowly transferred from a positive torque range to a negative torque range. In the positive torque, an acceleration force is transmitted to the motor vehicle 1. In the negative torque range, a drag torque is transmitted to the motor vehicle 1, by which the motor vehicle 1 is decelerated. In particular, the required tolerance width of the tolerance interval 23 is ensured by a correspondingly slow drop in the minimum value 22 for the deceleration. The difference between 4 and 5 is that the internal setpoint 25, which the control module 3 determines depending on the tolerance interval 23 and the acceleration potentials 9, in 4 by default has at most the predetermined temporal gradient. In other words, the internal setpoint 25 is determined in such a way that its temporal gradient does not exceed the predetermined temporal gradient.

In contrast, in the driving situation according to 5 a dynamic command 28 is transmitted by the driver assistance module 4 to the control module 3. By transmitting this dynamic command 28, the application of the predetermined gradient is at least partially overridden. In the present embodiment, it is provided that the internal setpoint value 25 is determined in such a way that, when the dynamic command 28 is present, it drops to the deceleration value of the thrust potential 32 without taking the predetermined gradient into account. Only when the deceleration of the thrust potential 32 is exceeded is the internal setpoint value 25 determined in such a way that its temporal gradient does not exceed the predetermined temporal gradient. This is in a range 27 of the 5 In the driving situations according to 4 and 5 the recuperation potential 33 lies within the tolerance interval 23. Accordingly, in both driving situations, deceleration of the motor vehicle 1 is only possible through recuperation without violating or leaving the tolerance interval 23. Accordingly, the control module 3 controls the brake unit 6 and the drive unit 5 in such a way that the deceleration of the motor vehicle 1 takes place exclusively through recuperation, in particular without using the brake unit 6. In the driving situation according to 6 however, the recuperation potential 33 is not within the tolerance interval 23, in particular because this has the tolerance range 0. In other words, the target value 20 corresponds to the minimum value 22. For this reason, the control module 3 controls the drive unit 5 and the brake unit 6 in this case such that the resulting acceleration 26 corresponds to the target value 20 or the minimum value 22. Even in the driving situation according to 6 the dynamic command 28 prevents the application of the temporal gradient up to the acceleration level of the thrust potential 32. In other words, the transmission of the dynamic command 28 in a braking maneuver results in an immediate reduction in the throttle, which means that a positive torque of the drive unit 5 is reduced as quickly as possible. The shading in the area 40 indicates the use of the braking unit 6, i.e. in particular a friction brake.

Last shows 7 a driving situation in which the motor vehicle 1 is transferred from deceleration to acceleration. The dynamic command 28 is also used here. By transmitting the dynamic command 28, the temporal gradient is not taken into account when the deceleration is reduced. In particular, it can be provided that when the dynamic command is transmitted, a braking force of the braking unit 6 is reduced as quickly as possible. The temporal gradient is then taken into account when the motor vehicle 1 is accelerated. In other words, the temporal gradient is taken into account when a positive torque is provided by the drive unit 5 and is not exceeded.

Overall, the exemplary embodiment can improve the range of a motor vehicle or minimize its energy consumption. The interaction between the driver assistance module 4 and the control module 3 can also be improved. Independent development of both the control module 3 and the driver assistance module 4 is possible because the two systems need to be coordinated with one another less due to the increased flexibility. Each of the two modules 3, 4 can optimize its respective operating state within the given limits. The dynamic command 28 can also save energy by reducing the drive power more quickly in the event of an impending deceleration or braking maneuver. Energy is also saved by reducing the braking unit 6 or the deceleration by the braking unit 6 more quickly in the event of an impending acceleration maneuver.

Overall, the examples show how the invention can provide an interface between driver assistance functions (ACA, ACC, GRA, LIM, ISA) and drive/brake (VMM) with regard to the efficient use of drive and brake.

Claims (10)

Method for controlling the longitudinal dynamics of a motor vehicle (1), comprising the steps of: - determining a tolerance interval (23) for an acceleration or deceleration of the motor vehicle (1) by a driver assistance module (4), - transmitting the tolerance interval (23) to a control module (3) for the longitudinal dynamics of the motor vehicle (1), - determining different acceleration potentials (9) by the control module (3), wherein the acceleration potentials (9) each have a value for an acceleration or deceleration which can be achieved in a respective predetermined operating state of a drive unit (5) and/or a brake unit (6) of the motor vehicle (1), and - controlling the drive unit (5) and/or the brake unit (6) of the motor vehicle (1) by the control module (3) depending on the tolerance interval (23) and the acceleration potentials (9), so that a resulting acceleration or deceleration of the motor vehicle (1) results within the tolerance interval (23), characterized in that - the acceleration or deceleration of the motor vehicle (1) is controlled by the control module (3) in such a way that a predetermined temporal gradient is not exceeded regardless of the transmitted tolerance interval (23), wherein if the driver assistance module specifies a change from deceleration to acceleration during a braking maneuver using the tolerance interval (23), only when the dynamic command (28) is transmitted is the deceleration reduced as quickly as possible by appropriately controlling the braking unit by the control module (3) and the acceleration is then controlled in such a way that the predetermined temporal gradient is not exceeded, and/or - the tolerance interval (23) is determined by determining a target value (20) and a minimum value (21, 22) for the acceleration or deceleration, wherein the tolerance interval (23) lies between the target value (20) and the minimum value (21, 22), and wherein during a driving maneuver the target value (20) remains constant in time and the minimum value (21, 22) increases in time towards the target value (20) is shifted so that the tolerance interval (23) becomes narrower. Procedure according to Claim 1 , characterized in that for determining the acceleration potentials (9), in addition to the respective operating state of the drive unit (5) and/or the brake unit (6), one or more of the following variables are additionally taken into account: a mass of the motor vehicle (1), a gradient of a roadway currently being traveled on, a driving resistance and/or route data from a navigation system. Method according to one of the preceding claims, characterized in that at least one of the following operating scenarios is taken into account by the predetermined operating conditions (9): maximum acceleration (30) by all drive units, maximum acceleration (31) only by an electric motor (12) of the drive unit (5), maximum acceleration without gear change in a transmission of the motor vehicle, deceleration in coasting mode, maximum deceleration solely due to drag losses (32) and/or recuperation (33), maximum deceleration due to recuperation. Method according to one of the preceding claims, characterized in that the different acceleration potentials (9) are transmitted by the control module (3) to the driver assistance module (4). Procedure according to Claim 4 , characterized in that the acceleration potentials (9) transmitted to the driver assistance module (4) are taken into account for subsequent planning of a further tolerance interval (23). Method according to one of the preceding claims, characterized in that the tolerance interval (23) is determined in such a way that, when initiating a non-safety-critical braking maneuver, it increases sufficiently slowly to higher deceleration values in order to avoid intervention of the braking unit (6), in particular a friction brake, before completion of load impact damping (29) on the drive unit (5). Method according to one of the preceding claims, characterized in that the drive unit (5) comprises an electric motor (12) and an internal combustion engine (13) and the tolerance interval (23) is determined such that it has a sufficient tolerance range during an acceleration maneuver in order to avoid switching on the internal combustion engine (13). Method according to one of the preceding claims, characterized in that only in the case of the additional transmission of a dynamic command (28) from the driver assistance module (4) to the control module (3) is the acceleration or deceleration of the motor vehicle (1) controlled by the control module (3) such that the predetermined temporal gradient is exceeded when the tolerance interval (23) specifies a corresponding acceleration or deceleration. Motor vehicle control system (2) for controlling longitudinal dynamics of a motor vehicle (1), with a driver assistance module (4) and a control module (3), characterized in that the motor vehicle control system (2) is designed to carry out a method according to one of the preceding claims. Motor vehicle (1) with a motor vehicle control system (2) according to Claim 9 .

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