Force-based determination of a target gear combination for a plurality of drive systems

Abstract

The invention relates to a method for determining a target gear combination for a vehicle with at least two drive systems, wherein each drive system drives one vehicle axle and each of the two drive systems has at least one electric motor and at least one transmission with in each case at least two gears, the method comprising the following steps: determining the target gear combination based on a route which lies ahead and / or a speed and / or an acceleration of at least one vehicle travelling ahead and / or behind and / or based on a distance to at least one vehicle travelling ahead and / or behind.

Description

[0001] Force-based determination of a target gear combination for multiple drive systems

[0002] The present disclosure relates to a method for determining a target gear combination for a vehicle, in particular a truck and / or a bus, for example a city bus, or a watercraft with at least two drive systems. The vehicle can be driven manually and / or by an automated driving system. When determining the target gear combination, the route ahead and / or parameters of other vehicles are taken into account.

[0003] State of the art

[0004] In vehicles with only one drive system powered by an electric motor, the electric motor must provide a high level of power to sufficiently accelerate the vehicle, especially a truck. Electric motors operate particularly efficiently at a power utilization of 50 percent or more. Therefore, electric motors with a very high maximum power operate very inefficiently at low acceleration. Furthermore, it may be that a single electric motor cannot provide sufficient power to sufficiently accelerate the vehicle, for example when the truck is fully loaded. Furthermore, the electric motors can overheat if they are operated at too high a power for too long. Therefore, the use of electric motors in trucks is still limited.

[0005] By using multiple drive systems, each with at least one electric motor, each driving a drive axle of the vehicle, the drive torques (braking torques) of the drive systems can be added together to produce a sufficient total drive torque. For example, the use of multiple drive systems, each with at least one electric motor, makes it possible to use electric motors with low power while still ensuring sufficient acceleration of the vehicle. In order to change the vehicle's total drive torque, it is advantageous to adapt the power range of an electric motor using a transmission. The multiple drive systems result in several possible gear combinations for the transmissions of the drive systems. The different gear combinations of the drive systems make it possible to provide the vehicle with different maximum total drive torques and / or minimum resistance torques (braking torques).Therefore, the correct gear combination must be selected depending on the driving situation.

[0006] Furthermore, vehicles, especially trucks or watercraft, are subject to very different requirements. This means that different vehicles use electric motors and / or transmissions with different torque characteristics in order to optimally adapt the power range and / or the power ranges of the total drive torque to the vehicle's requirements. Therefore, it is further advantageous to specify a method for calculating a target gear combination that can be automatically or easily adapted to the different requirements of the vehicles.

[0007] Summary of the invention

[0008] The object of the present invention is to provide a method for calculating the target gear combinations of the transmissions of drive trains for vehicles with multiple drive trains, which can provide the vehicle drive trains with a sufficient total driving force and / or total resistance force depending on the situation using a simple calculation method.

[0009] Furthermore, it is an object of the present invention to provide a method for calculating the target gear combination, which can be transferred to any drive train concepts with a different number of gears of the transmissions and different torque characteristics of the transmissions and / or the electric motors.

[0010] Furthermore, it is an object of the present invention to provide a method for calculating the target gear combination which can be easily adapted to different loads of the vehicle or to a different vehicle weight.

[0011] Furthermore, it is an object of the present invention to take into account parameters of the route or of surrounding vehicles.

[0012] Furthermore, it is an object of the present invention to provide a vehicle which uses such a method or in which such a method is used.

[0013] The invention is based on the idea of ​​using multiple motors to drive vehicles in order to increase the vehicle's drive power. Several small or low-dimensioned electric motors can be used, while the vehicle can still deliver a high or the required drive power. The aim is to provide a method for selecting and activating a target gear combination for the transmissions located between the drive axles and the motors. This method ensures, on the one hand, that sufficient torque can be provided by the drive axles and, on the other hand, that the electric motors of the drive systems are sufficiently utilized so that they operate within an efficient operating range.In order to be able to take several drive systems, each with an electric motor and a transmission, into account when determining the target gear combination, a method is specified which determines the target gear combination in a force-based manner, ie on the basis of a comparison of a longitudinal force requirement and a force that can be provided with the individual gear combinations of the transmissions of the two drive systems.

[0014] These objects are achieved by the features of the independent claims. Preferred embodiments are specified in the dependent claims.

[0015] According to the invention, a method is provided for determining a target gear combination for a vehicle with at least two drive systems or drive trains, wherein each drive system drives a vehicle axle and each of the two drive systems has at least one motor and at least one transmission, wherein at least one of the motors is an electric motor and at least one transmission has two gears; wherein the method comprises the following step: determining the target gear combination based on a comparison of a longitudinal force requirement with maximum total drive forces and / or minimum total resistance forces of possible gear combinations of the at least two transmissions, wherein the maximum total drive forces are the sum of the maximum drive forces of the possible gear combinations and the minimum total resistance forces are the sum of the minimum resistance forces of the possible gear combinations;and / or wherein the longitudinal force requirement is determined based on a route ahead; and / or wherein the longitudinal force requirement is determined based on a speed and / or acceleration of at least one preceding and / or following vehicle and / or based on a distance to at least one preceding and / or following vehicle.

[0016] The target gear combination is the gears that the individual transmissions should have or the gears into which the individual transmissions of the at least two drive systems should be shifted. For example, the transmissions of the at least two drive systems have two, three, or four gears. The individual gears of the transmissions of the at least two drive systems allow the electric motors of the at least two drive systems to apply different torques to the vehicle axles at the same electric motor speed.

[0017] The driven vehicle axles can be rear axles and / or front axles. The vehicle can also comprise only one rear axle driven by a drive system. Furthermore, the vehicle can also comprise two front axles, wherein one or both front axles can be driven. Several front axles and / or several rear axles can be driven and / or all vehicle axles can be driven. The drive system for driving one vehicle axle in each case can comprise an electric motor. However, instead of the electric motor, the drive system can also comprise another and / or additional motor, for example an internal combustion engine. Furthermore, the drive systems can be operated independently of one another, i.e. the drive systems are not in direct operative connection with one another. Each of the drive systems comprises one of the at least two transmissions.

[0018] The longitudinal force demand is the force that the vehicle is currently expected to provide. The longitudinal force demand takes into account, for example, how much force is currently being requested from the vehicle by a driver and / or an automated driving system, and / or a force that will be required due to a current road gradient and / or a road gradient in a future section of the road, and / or a force that reflects an expected additional force input from the driver and / or the automated driving system.

[0019] The maximum total drive forces are the maximum total drive forces that the drive systems can deliver to the driven axles in a selected gear combination, or the maximum drive forces with which the drive systems can accelerate the driven axles in a gear combination. The total drive forces are defined in the direction of travel of the vehicle and are therefore positive.

[0020] The minimum total resistance forces are the total resistance forces that all drive systems in a selected gear combination can provide to the driven axles, i.e., the maximum resistance forces with which the drive systems in a gear combination can brake the driven axles. The total resistance forces are defined against the direction of travel of the vehicle and are therefore negative. The minimum resistance forces are positive in magnitude and the maximum resistance forces of the respective gear of the respective transmission, i.e., the combination of gears of the multiple transmissions that exert a maximum resistance force (braking force).

[0021] For example, the longitudinal force requirement is calculated based on the route ahead.

[0022] The route ahead can be determined, for example, using digital map data and / or sensors such as LIDAR, RADAR, or cameras. For example, the vehicle is located on the digital map using GPS and / or characteristic landmarks, such as traffic signs. The route ahead can then be divided into individual sections. Based on the route ahead, the longitudinal force requirement can be reduced during manual driving (via the accelerator and / or brake pedal) and / or even omitted in certain situations when using an automated driving system.

[0023] Gradients and / or town entrances and / or speed limits can be stored in the route ahead and / or in the individual route sections ahead. Furthermore, speed profiles or acceleration profiles for the vehicle can be specified for the route ahead and / or the individual route sections ahead. Furthermore, target speeds and / or target accelerations can be specified at characteristic points, such as a town entrance or a pass or a transition between a positive and negative gradient, and a controller can, for example, calculate an energy- and / or time-optimized speed profile or acceleration profile for the vehicle on the route ahead and / or the individual route sections ahead.Based on the speed and / or acceleration curves, the longitudinal force requirement can be determined predictively and energy-efficiently. Based on the speed and / or acceleration curves, the longitudinal force requirement can be reduced during manual driving and / or even omitted in certain situations when driving an automated driving system.

[0024] For example, the longitudinal force requirement is calculated based on a speed and / or acceleration of at least one preceding and / or following vehicle and / or based on a distance to at least one preceding and / or following vehicle.

[0025] This can be used, for example, to make platooning energy efficient. Platooning describes a system for road traffic in which several vehicles can drive one behind the other at a very close distance with the help of a technical control system without compromising road safety. The speed and / or acceleration of the vehicle in front and / or behind can be the current speed and / or acceleration of the vehicle in front and / or behind and / or a planned or anticipated speed and / or acceleration of the vehicle in front and / or behind. The distance to at least one vehicle in front and / or behind can be a current distance and / or a planned distance to at least one vehicle in front and / or behind.The speed and / or acceleration of and / or the distance to several vehicles driving ahead and / or behind can also be taken into account simultaneously. For example, at the beginning of the procedure or when initializing the algorithm, at least two transmissions of at least two drive systems are initially in neutral.

[0026] For example, the process is started or initialized as soon as the longitudinal force request is made for the first time after the vehicle has started and / or after the vehicle has come to a standstill.

[0027] The target gear combination is determined by comparing the desired and maximum forces acting on the wheel, thus being purely force-based. This automatically takes the vehicle mass into account in the calculation, allowing the same method to be used for different torque characteristics of the transmissions and electric motors, for different vehicle types, and with different loads.

[0028] Preferably, the determination of the maximum total drive forces and the minimum total resistance forces takes into account gear combinations as the possible gear combinations in which at least one of the at least two transmissions is in neutral. Preferably, the neutral of one or more transmissions of the drive systems is taken into account as an additional gear when determining the gear combinations.

[0029] Depending on the speed, it is also possible to omit certain gears from the selection or target gear determination process because their activation is unlikely or technically impossible. This can limit the number of practically selectable gears, and some theoretically possible gear combinations can be ignored in the practical selection.

[0030] This can, for example, ensure that the electric motors of the individual drive systems are operated with optimal power utilization. To do this, it may be more energy-efficient to deactivate at least one drive system or to idle its transmission and instead place a higher load on the other drive system or systems, thus operating them in a more energy-efficient range. The electric motor can, for example, operate energy-efficiently if the electric motor provides 50 percent or more of its maximum torque. Therefore, the vehicle can be operated more energy-efficiently in certain situations if one drive system is idle and the electric motor of another drive system is therefore more heavily utilized, i.e., for example, provides more than 50 percent of its maximum torque.

[0031] Preferably, in the method for determining the target gear combination, if the longitudinal force requirement is greater than and / or equal to zero, the target gear combination is determined by comparing the longitudinal force requirement with the maximum total drive forces and otherwise by comparing it with the minimum total resistance forces.

[0032] If the longitudinal force request is positive, it is assumed, for example, that the vehicle is being accelerated by the user and / or the automated driving system and / or due to a positive gradient. Therefore, the target gear combination can be determined that can provide the vehicle with sufficient or as much total drive torque as possible. If the longitudinal force request is negative, it can be assumed, for example, that the vehicle is being braked by the user and / or the automated driving system, for example, due to a negative gradient. Therefore, the target gear combination can be determined that can provide the vehicle with sufficient or as much total resistance torque as possible.

[0033] Preferably, in the method for determining the target gear combination, if no maximum total drive force is greater than and / or equal to the longitudinal force requirement, the gear combination with the maximum total drive force is selected as the target gear combination. This ensures that the drive systems can be fully utilized.

[0034] Preferably, in the method for determining the target gear combination, if no maximum total drag force is less than and / or equal to the longitudinal force requirement, the gear combination is selected as the target gear combination that has the minimum total drag force. This ensures that the drive systems can be fully utilized.

[0035] Preferably, in the method for determining the target gear combination, the target gear combination is determined such that a gear combination is selected in which the gear is changed only in the smallest possible number of the at least two transmissions.

[0036] For example, it is first checked whether the actual gear combination is one with sufficient total drive force or total resistance force. If this is not the case, it can be checked whether a gear combination can be used as the target gear combination, i.e. a gear combination is one of the gear combinations with sufficient total drive force or total resistance force, in which only a gear needs to be changed in the transmission of one of the drive systems. If this is not the case, it is checked whether a gear combination can be used as the target gear combination in which only a gear needs to be changed in two transmissions, and so on, in order to ensure that power or torque can be transmitted to as many drive axles as possible simultaneously during a gear change.Preferably, when changing gears in multiple gear combinations, each involving the same minimum number of gears, the gear combination with the smallest total maximum drive forces and / or the largest total minimum drag forces is selected. This allows the drive systems to operate in the gear combination that is most energy-efficient for the vehicle.

[0037] Preferably, the longitudinal force requirement is determined from a force reserve and a force input.

[0038] The force input can be generated or specified by the driver and / or by the automated driving system. The driver provides the force input, for example, via the position of an accelerator pedal or via an accelerator pedal position and / or a brake pedal position or via a brake pedal position. The accelerator pedal position and / or brake pedal position is then converted into a force input. The automated driving system calculates, for example, a target acceleration, which is converted into the force input by multiplying it by a vehicle mass, for example. The target acceleration is preferably the acceleration in the longitudinal direction of the vehicle.The force input can also be specified in combination by the driver and the automated driving system, for example, in the case of a hill start assist, the force input of the automated driving system can prevent the vehicle from rolling back on a hill and accelerate the vehicle through the force input of the driver.

[0039] When determining the target gear combination, the power reserve is preferably determined from an acceleration reserve and a vehicle mass.

[0040] The power reserve can be equal to the vehicle mass times the vehicle acceleration. The vehicle mass can be a measured value and / or an estimated value. The vehicle mass can either be measured via sensors or determined indirectly, for example, via the vehicle's acceleration behavior.

[0041] The acceleration reserve is a value indicating how much the total drive force and / or the total resistance force is already being utilized. This means that the acceleration reserve indicates how much the vehicle can still accelerate and / or decelerate in the current gear combination. Furthermore, the acceleration reserve can determine, depending on the maximum vehicle acceleration and deceleration, how much the vehicle should still accelerate and / or decelerate, for example, without exceeding the vehicle's system limits and providing the driver with good drivability. The acceleration reserve is preferably determined from the power utilization and the acceleration utilization.

[0042] Preferably, the acceleration reserve is determined from a map having a value for each force input and acceleration input, wherein if the force input is greater than or equal to zero, the value is multiplied by a maximum vehicle acceleration and / or otherwise the value is multiplied by a maximum vehicle deceleration.

[0043] The maximum acceleration depends, for example, on the vehicle type and / or the current vehicle speed. Furthermore, the maximum acceleration can be determined in such a way that energy efficiency during driving is increased. The maximum deceleration depends, for example, on the vehicle type and / or the vehicle mass. Furthermore, the maximum deceleration can be determined in such a way that energy efficiency during driving is increased.

[0044] Preferably, if the force input is greater than or equal to zero, the force utilization is determined from a ratio of the force input to a maximum total drive force of an actual gear combination of the at least two transmissions and / or otherwise the force utilization is determined from a ratio of the force input to a maximum total resistance force of the actual gear combination of the at least two transmissions.

[0045] Preferably, when the force input is greater than and / or equal to zero, the acceleration utilization is determined from a ratio of a vehicle acceleration to the maximum vehicle acceleration and / or otherwise the acceleration utilization is determined from a ratio of a vehicle deceleration to the maximum vehicle deceleration.

[0046] The vehicle acceleration corresponds to a positive acceleration or an acceleration equal to zero, and the vehicle deceleration corresponds to a negative acceleration. The vehicle acceleration and deceleration are preferably indicated on the same signal, or the vehicle acceleration and deceleration are preferably indicated as the same value within a specific numerical range.

[0047] For example, the acceleration reserve is calculated based on the route ahead.

[0048] The route ahead can be determined, for example, using digital map data and / or sensors such as LIDAR, RADAR, or cameras. For example, the vehicle is located on the digital map using GPS and / or characteristic landmarks, such as traffic signs. The route ahead can then be divided into individual route sections.

[0049] Depending on the route ahead, the acceleration reserve can be reduced when driving manually (using the accelerator and / or brake pedal) and / or even omitted in certain situations when driving with an automated driving system.

[0050] Gradients and / or town entrances and / or speed limits can be stored in the route ahead and / or in the individual route sections ahead. Furthermore, speed profiles or acceleration profiles for the vehicle can be specified for the route ahead and / or the individual route sections ahead. Furthermore, target speeds and / or target accelerations can be specified at characteristic points, such as a town entrance or a pass or a transition between a positive and negative gradient, and a controller can, for example, calculate an energy- and / or time-optimized speed profile or acceleration profile for the vehicle on the route ahead and / or the individual route sections ahead.Based on the speed and / or acceleration curves, the acceleration reserve can be determined predictively and energy-efficiently. Based on the speed and / or acceleration curves, the acceleration reserve can be reduced during manual driving and / or even omitted in certain situations when using an automated driving system.

[0051] For example, the acceleration reserve is calculated based on a speed and / or acceleration of at least one vehicle driving ahead and / or behind and / or based on a distance to at least one vehicle driving ahead and / or behind.

[0052] This can be used, for example, to make platooning energy efficient. Platooning describes a system for road traffic in which several vehicles can drive one behind the other at a very close distance with the help of a technical control system without compromising road safety. The speed and / or acceleration of the vehicle in front and / or behind can be the current speed and / or acceleration of the vehicle in front and / or behind and / or a planned or anticipated speed and / or acceleration of the vehicle in front and / or behind. The distance to at least one vehicle in front and / or behind can be a current distance and / or a planned distance to at least one vehicle in front and / or behind.The speed and / or acceleration of and / or the distance to several vehicles ahead and / or behind can also be taken into account simultaneously.

[0053] Preferably, the force input is limited. The force input is preferably limited before the acceleration reserve, the force reserve, and the force input are calculated. The force input can also be limited only if the force input is greater than zero. If the force input is less than zero, it may be advantageous not to limit the force input downwards in order to provide the vehicle with maximum braking torque (maximum recuperation).

[0054] Preferably, the limited force input is determined from the minimum of the force input and a sum of a resistance acceleration and the maximum vehicle acceleration times the vehicle mass.

[0055] The resistance acceleration depends on rolling resistance and / or a gradient. The rolling resistance and / or the gradient or road incline can be determined, for example, by sensors. Furthermore, the rolling resistance and / or the gradient can be read from the route ahead and / or individual sections of the route ahead.

[0056] The present invention comprises a non-transitory, computer-readable storage medium for physically storing computer program instructions executable by a processor, the computer program instructions defining the method for determining the desired gear combination.

[0057] The present invention further comprises a vehicle having at least two drive systems for driving one vehicle axle each, wherein each drive system comprises: an electric motor and at least one transmission having at least two gears each, wherein the electric motor is operatively connected to the transmission; and a controller configured to carry out the method for determining the target gear combination.

[0058] Brief description of the drawings

[0059] The invention is described in detail below with reference to the figures:

[0060] Figure 1 shows a vehicle with a control system that is configured to carry out a method for determining a target gear combination.

[0061] Figure 2 shows the vehicle shown in Figure 1 from below; Figure 3 shows a flowchart of a method for determining a target gear combination;

[0062] Figure 4 shows a block diagram configured to carry out a method for determining the target gear combination;

[0063] Figure 5 shows a block diagram of the target gear combination determination module shown in Figure 3, which is configured to determine the target gear combination;

[0064] Figure 6 shows a block diagram of a module arranged in the module for determining a target gear combination shown in Figure 4, which is arranged to determine the possible gear combinations;

[0065] Figure 7 shows a block diagram of a module arranged in the module for determining a target gear combination shown in Figure 4, which is arranged to determine the optimal gear combination;

[0066] Figure 8 shows a block diagram of a module for determining a target gear combination, which is shown in Figure 3 and is arranged to determine a power reserve;

[0067] Figure 9 shows a block diagram of a module for determining total driving forces, shown in Figure 3, which is configured to determine maximum total driving forces of the possible gear combinations and maximum total resistance forces of the possible gear combinations;

[0068] Figure 10 shows a block diagram of the limited force input determination module shown in Figure 3, which is configured to limit a force input.

[0069] Embodiments of the invention

[0070] In the following, unless otherwise stated, the same reference symbols are used for identical and equivalent elements.

[0071] Figure 1 shows a vehicle 1, in particular a truck, with three vehicle axles 4. The vehicle 1 comprises a front axle 43 and a first rear axle 41 and a second rear axle 42. The first rear axle 41 is located between the front axle 43 and the second rear axle 42. The vehicle 1 further comprises a controller 100 which is configured to carry out a method for determining a desired gear combination.

[0072] Figure 2 shows the vehicle 1, which is illustrated in Figure 1, from below. The first rear axle 41 and the second rear axle 42 are each driven by an electric motor 2. A transmission 3 is arranged between the first rear axle 41 and the second rear axle 42 and the respective electric motor 2. Figure 3 shows the method for determining the target gear combination 1000, which comprises a step S 1001 for determining the target gear combination based on a comparison of a longitudinal force requirement with maximum total drive forces and / or minimum total resistance forces of possible gear combinations of the at least two gears of the at least two transmissions.

[0073] Figure 4 shows a block diagram for determining the target gear combination 110, which is configured to carry out the method for determining the target gear combination 1000.

[0074] The block diagram shows a module for determining a limited force input M100, a module for determining total drive forces M200 (or for determining total resistance forces), a module for determining a force reserve M300 and a module for determining a target gear combination M400.

[0075] The module for determining the target gear combination M400 can be configured to determine the target gear combination 110. The input variables of the module for determining the target gear combination M400 can be a force input 210, a force reserve 160, maximum total resistance forces of the possible gear combinations 150, maximum total drive forces of the possible gear combinations 140, a minimum total resistance force of the actual gear combination 155, and a maximum total drive force of the actual gear combination 145. The force reserve 160 specifies how much force, drive force, or resistance force, should be kept as a reserve in addition to the force input.

[0076] For example, the power reserve determination module M300 is configured to determine the power reserve 160. The input variables of the power reserve determination module M300 are, for example, the power input 210, a maximum vehicle acceleration 181 and a maximum vehicle deceleration 182, a vehicle acceleration or deceleration 180, a vehicle mass 120, the maximum total drive force of the actual gear combination 145, and the minimum total resistance force of the actual gear combination 155.

[0077] The maximum vehicle acceleration 181 and / or the maximum vehicle deceleration 182 depends, for example, on a vehicle speed or the current vehicle speed and / or on a vehicle type. The maximum vehicle acceleration 181 and / or the maximum vehicle deceleration 182 can also depend on the route ahead. The route ahead can be determined, for example, by a digital map or by the vehicle's sensors. The vehicle acceleration or deceleration 180 is a current acceleration value of the vehicle. The vehicle acceleration or deceleration 180 can be positive, negative, or zero. The maximum total drive force of the actual gear combination 145 is a force that the vehicle's drive systems can make available to the vehicle for acceleration in the current gears of the drive systems' transmissions.The minimum total resistance force of the actual gear combination 155 is a force with which the drive systems of the vehicle can maximally brake the vehicle in the current gears of the transmissions of the drive systems.

[0078] The force input 210 can be limited. For example, the module for determining the limited force input M100 is configured to determine the limited force input 210 (shown in dashed lines). The module for determining the limited force input M100 is optional. The module for determining the limited force input 210 can, for example, have as input variables the driving input 210 or a still unlimited force input 210, an ambient acceleration 170, the maximum vehicle acceleration 181 and / or the maximum vehicle deceleration 182. The ambient acceleration 170 is determined, for example, based on a gradient of the road. The gradient can be the current gradient and / or the gradient from a route ahead. The route ahead can, for example, be read from a digital map and / or determined by a vehicle sensor, e.g., a camera.Furthermore, the ambient acceleration 170 can also be calculated from a route ahead or from state variables of the surrounding vehicle. The state variables of the surrounding vehicles include, for example, a distance to the surrounding vehicle, a speed of the surrounding vehicle, and the acceleration and / or jerk of the surrounding vehicle. For example, the surrounding vehicle is a vehicle in front of and / or behind the vehicle that is applying the method for determining the target speed. The ambient acceleration 170 can be positive or negative.

[0079] An exemplary embodiment of the module for determining the target gear combination M400 is shown in Figure 5. The module for determining the target gear combination M400 comprises, for example, a module for determining possible target gear combinations M401, a module for determining optimal gear combinations M402, and a module for forming a hysteresis. First, a longitudinal force requirement 130 is determined in the module for determining the target gear combination M400. The longitudinal force requirement 130 is calculated, for example, from the sum of the force reserve 160 and the force input 210. The module for determining possible target gear combinations M401 can be configured to determine the gear combinations with sufficient total drive force or total resistance force 112.Input variables of the module for determining possible target gear combinations M401 can be the longitudinal force requirement 130 and the maximum total drive forces of the possible gear combinations 140 and the maximum total drive forces of the possible gear combinations 150. The module for determining the optimal gear combination M402 can be configured to determine the target gear combination 110. Input variables of the module for determining the optimal gear combination M402 can be the gear combinations with sufficient total drive force or total resistance force 112. The module for forming the hysteresis M403 (shown in dashed lines) is optional.

[0080] The module for forming the hysteresis M403 can be configured to prevent the target gear combination from changing too often. Input variables of the module for forming the hysteresis M403 can be the longitudinal force requirement 130, the maximum total driving forces of the possible gear combinations 140, the minimum total resistance forces of the possible gear combinations 150, an actual gear combination 111, a maximum total driving force of the actual gear combination 145, and a minimum total resistance force of the actual gear combination 155. The module for forming the hysteresis M403 is configured, for example, to only change the target gear combination 110 when the longitudinal force requirement 130 can no longer be met by the actual gear combination 110, i.e.if a comparison of the maximum total drive force of the actual gear combination 145 is less than and / or equal to the longitudinal force requirement 130 and / or if a comparison of the minimum total resistance force of the actual gear combination 155 is greater than and / or equal to the longitudinal force requirement 130. A safety parameter can be taken into account in this comparison. Furthermore, the module for forming the hysteresis M403 can be configured to wait a period of time after a change in the target gear combination 110 until a further change in the target gear combination 110 is possible. Furthermore, the module for forming the hysteresis M403 can be configured to reduce oscillations in the longitudinal force requirement 130, for example by means of a low-pass filter, before the longitudinal force requirement 130 is used to determine the target gear combination 110.

[0081] The module for determining possible target gear combinations M401, which is configured to determine gear combinations with sufficient total drive force or total resistance force 112, is shown by way of example in Figure 6. The module for determining possible target gear combinations M401 can comprise a comparison module M4011 and a comparison module M4012. The comparison module 4011 can be configured to determine the gear combinations with sufficient total drive force 113 based on the longitudinal force requirement 130 and the maximum total drive forces of the possible gear combinations 140, i.e., gear combinations with sufficient total drive force 113 can be those gear combinations whose maximum total drive forces are greater than and / or equal to the longitudinal force requirement 130.The comparison module 4012 can be configured to determine the gear combinations with sufficient total resistance force 114 based on the longitudinal force requirement 130 and the maximum total resistance forces of the possible gear combinations 150, i.e., gear combinations with sufficient total drive force 114 can be those gear combinations whose maximum total drive forces are less than and / or equal to the longitudinal force requirement 130. By way of example, the module for determining possible target gear combinations M401 is configured to select the gear combinations with sufficient total drive force 140 as gear combinations with sufficient total drive force or total resistance force 112 if the longitudinal force requirement 130 is greater than and / or equal to zero, and otherwise to select the gear combinations with sufficient total resistance force 150 as gear combinations with sufficient total drive force or total resistance force 112.

[0082] The module for determining the optimal gear combination M402, which is configured to determine the target gear combination 110, is shown by way of example in Figure 7. The module for determining the optimal gear combination M402 can comprise a comparison module M4021, a comparison module M4022, and a comparison module M4023.

[0083] The comparison module M4021 can be configured to determine, from an actual gear combination 111 and a gear combination with sufficient total drive force or total resistance force 112, those gear combinations with the smallest possible changes in the gears of the transmissions of the drive systems 115. For example, the comparison module M4021 is configured to first check whether the actual gear combination 111 is one of the gear combinations with sufficient total drive force or total resistance force 112. If this is the case, the actual gear combination 111 can be selected as the gear combination with the smallest possible changes in the gears of the transmissions of the drive systems 115.If this is not the case, the comparison module M4021 can be configured to determine, by comparing the actual gear combination 111 with the gear combinations with sufficient total drive force or total resistance force 112, those gear combinations as gear combinations with the smallest possible changes to the gears of the transmissions of the drive systems 115, in which only one gear, subsequently two gears, etc. of the at least two transmissions must be changed.

[0084] The comparison module M4022 can be configured to determine the target gear combination 110 by comparing the gear combinations with the smallest possible changes in the gears of the transmissions of the drive systems 115 and the maximum total drive forces of the possible gear combinations 140. The gear combination with the smallest possible changes in the gears of the transmissions of the drive systems 115 that has the smallest total drive force can be selected as the target gear combination 110. For example, if there are no gear combinations with sufficient total drive force or total resistance force 112 and thus no gear combinations with minor changes in the gears of the transmissions of the drive systems 115, the comparison module can further be configured to select the gear combination with the greatest total drive force as the target gear combination 110.

[0085] The comparison module M4023 can be further configured to determine the target gear combination 110 by comparing the gear combinations with the smallest possible changes in the gears of the transmissions of the drive systems 115 and the maximum total resistance forces of the possible gear combinations 150. The gear combination of the gear combinations with the smallest possible changes in the gears of the transmissions of the drive systems 115 that has the greatest total resistance force can be selected as the target gear combination 110. For example, if there are no gear combinations with sufficient total drive force or total resistance force 112 and thus no gear combinations with minor changes in the gears of the transmissions of the drive systems 115, the comparison module can be further configured to select the gear combination with the smallest total resistance force as the target gear combination 110.

[0086] The target gear combination 110 can be an output variable of the comparison module M4022 and an output variable of the comparison module M4023. Therefore, the module for determining the optimal gear combination 110 can be further configured to select the output variable of the comparison module M4022 or the output variable of the comparison module M4023 as the target gear combination 110 depending on the longitudinal force requirement 130. For example, the module for determining the optimal gear combination is configured to select the output variable of the comparison module M4022 as the target gear combination 110 if the longitudinal force requirement 130 is greater than and / or equal to zero. Furthermore, the module for determining the optimal gear combination can be configured to select the output variable of the comparison module M4023 as the target gear combination 110 if the longitudinal force requirement 130 is less than and / or equal to zero.

[0087] The M300 power reserve determination module, which is designed to determine the power reserve

[0088] 160 is shown as an example in Figure 8. The module for determining the power reserve M300 comprises the characteristic map M301 and the characteristic map M302. The module for determining the power reserve M300 can be set up to calculate from an acceleration reserve

[0089] 161 and a vehicle mass 120. For this purpose, for example, the acceleration reserve 161 can be multiplied by the vehicle mass 120. The module for determining the power reserve M300 can be configured to determine the acceleration reserve 161 for a braking case and a drive case. The module for determining the power reserve M300 can be configured to determine the acceleration reserve 161 for the drive case if the power input is greater than and / or equal to zero and otherwise to determine the acceleration reserve 161 for the braking case. The module for determining the power reserve M300 can be configured to first determine a power utilization and an acceleration utilization. In the drive case, the power utilization can be a ratio of the power input 210 to the maximum total drive force of the actual gear combination 145.In the drive case, the acceleration utilization can be a ratio of the vehicle acceleration or deceleration 180 to the maximum vehicle acceleration 181. In the braking case, the force utilization can be a ratio of the force input 210 to the minimum total resistance force of the actual gear combination 155. In the braking case, the acceleration utilization can be a ratio of the vehicle acceleration or deceleration 180 to the maximum vehicle acceleration 181. Furthermore, the module for determining the power reserve M300 can be configured to read a value from a characteristic map M301 in the drive case and / or from a characteristic map M302 in the braking case, depending on the force utilization and the acceleration utilization.Subsequently, the power reserve determination module M300 can be configured to determine the acceleration reserve 161 by multiplying the value in the drive case by a maximum vehicle acceleration 181 and in the braking case by the maximum vehicle deceleration 182.

[0090] Using map M301 and / or map M302, acceleration reserve 161 can be adaptively adjusted to the driving situation, for example, regardless of the current speed. This results in a drive system or drive train state that is appropriate to the driving situation with minimal configuration effort. The configuration effort is minimal because it summarizes the driving situation—which depends, for example, on driving resistance, utilization of the current drive force, current acceleration, and maximum acceleration—in relative quantities and is therefore easily applicable to any driving situation. Preferably, an appropriate, but not excessive, acceleration reserve 161 is determined, which results in the electric motors of the drive systems operating in an efficient operating range, for example, with a torque between 60 percent and 90 percent, and only when necessary in a higher torque range.Furthermore, changes in the drive system or drive train, e.g. power reduction due to high temperatures of the electric motors of the drive systems, are automatically taken into account.

[0091] For example, map M301 and / or map M302 may have the following characteristics:

[0092] If the acceleration utilization is high and the power utilization is low, the acceleration reserve 161 can be small and / or zero. This can lead to a target gear combination with a lower maximum total drive force than the maximum total drive force of the actual gear combination. If the acceleration utilization is low to negative and the power utilization is high, the acceleration reserve 161 can be high. This can lead to a target gear combination with a greater maximum total drive force than the maximum total drive force of the actual gear combination.

[0093] If the acceleration utilization is high and the power utilization is high, the acceleration reserve 161 may be small and / or zero. This may result in a target gear combination that still has sufficient maximum total drive power.

[0094] If the power utilization is low to zero, the acceleration reserve 161 may be small and / or equal to zero. This can lead to a target gear combination with a lower maximum total drive force than the maximum total drive force of the actual gear combination. This causes the power utilization to increase again.

[0095] For example, the characteristic map M301 and / or the characteristic map M302 is designed such that when the power input changes, smooth transitions of the acceleration reserve are achieved. Furthermore, the characteristic map M301 and / or the characteristic map M302 can be designed such that, in combination with an axle load-dependent distribution of the longitudinal force requirement to the at least two drive systems, a moderate utilization of the adhesion value of the at least two drive systems results, with a further drive system of the at least two drive systems preferably only being activated when the utilization of the adhesion value of the at least two drive systems is high. The adhesion value refers to the adhesion of the wheels of the vehicle axles of the drive systems to the ground or the road.Furthermore, the method for determining a target gear combination can be transferred to any type and combination of drive systems by simply applying the map M301 and / or the map M302. Furthermore, the map M301 and / or the map M302 can have the same values ​​depending on the power utilization and the acceleration utilization, i.e., the same map can be used for both the drive and braking cases.

[0096] The module for determining the total drive forces M200 (or for determining the total resistance forces), which is configured to determine the maximum total drive forces of the possible gear combinations 140, the minimum total resistance forces of the possible gear combinations 150, the maximum total drive force of the actual gear combination 145, and the minimum total resistance force of the actual gear combination 155 as a function of the vehicle speed 200, is shown by way of example in Figure 9. The module for determining the total drive forces M200 can be configured to first determine maximum drive forces and resistance forces for each of the at least two drive systems.By way of example, Figure 9 shows a determination of maximum drive forces of a first drive system 141, a determination of minimum resistance forces of a first drive system 151, a determination of maximum drive forces of a second drive system 142 and a determination of minimum resistance forces of a second drive system 152 of the at least two drive systems.

[0097] To determine the maximum drive forces of the first drive system 141 and the minimum resistance forces of the first drive system 151 in the individual gears of the transmission of the first drive system, the module for determining the total drive forces M200 can comprise a module M2011 and a module M2021. First, the module for determining the total drive forces M200 can be configured to read out rotational speeds of the engine 201 of the first drive system from the module M2011 for each gear, depending on the vehicle speed 200. Subsequently, the module M2021 can be configured to determine the maximum drive forces of the first drive system 141 and the minimum resistance forces of the first drive system 151 for each gear, depending on the rotational speeds of the engine 201 of the first drive system.First, the module M2021 can be configured to determine maximum drive torques and resistance torques for each gear of the first drive system as a function of the rotational speeds of the motor 201 and subsequently to determine the maximum drive forces of the first drive system 141 and the minimum resistance forces of the first drive system 151 as a function of the maximum drive torques and resistance torques and of gear ratios for each gear of the first drive system.

[0098] To determine the maximum drive forces of the second drive system 142 and the minimum resistance forces of the second drive system 152 in the individual gears of the transmission of the first drive system, the module for determining the total drive forces M200 can comprise a module M2012 and a module M2022. First, the module for determining the total drive forces M200 can be configured to read out rotational speeds of the engine 202 of the second drive system from the module M2012 for each gear, as a function of the vehicle speed 200. Subsequently, the module M2022 can be configured to determine the maximum drive forces of the second drive system 142 and the minimum resistance forces of the second drive system 152 for each gear, as a function of the rotational speeds of the engine 202 of the second drive system.First, the module M2022 can be configured to determine maximum drive torques and resistance torques for each gear of the second drive system as a function of the speeds of the motor 202 of the second drive system, and subsequently, as a function of the maximum drive torques and resistance torques and gear ratios for each gear of the second drive system, to determine the maximum drive forces of the second drive system 142 and the minimum resistance forces of the second drive system 152. Subsequently, the module for determining the total drive forces M200 can be configured to determine, by means of a module M203, the maximum total drive forces of the possible gear combinations 140 and the minimum total resistance forces of the possible gear combinations 150. For this purpose, the module M203 can be configured to first determine the possible gear combinations.When determining the possible gear combination, the individual transmissions of the drive systems in idle mode can also be taken into account. Furthermore, the module 203 can be configured to add the maximum drive forces of the at least two drive systems, for example, the maximum drive force of the first drive system 141 and the maximum drive force of the second drive system 142, for the possible gear combination to determine the maximum total drive forces of the possible gear combinations 140. Furthermore, the module 203 can be configured to add the minimum resistance forces of the at least two drive systems, for example, the minimum resistance force of the first drive system 151 and the minimum resistance force of the second drive system 152, for the possible gear combination to determine the minimum total resistance forces of the possible gear combinations 150.If the idle of the transmissions of at least two drive systems is taken into account for the possible gear combinations, a driving force and / or a resistance force of zero is assumed for the drive system whose transmission is in idle.

[0099] Subsequently, the module for determining the total drive forces M200 can be configured to determine, by means of a module M204, the maximum total drive force of the actual gear combination 145 and the minimum total resistance force of the actual gear combination 155 from the maximum total drive forces of the possible gear combinations 140, the minimum total resistance forces of the possible gear combinations 150 and the actual gear combination 111.

[0100] The module for determining a limited force input M100, which is configured to limit the force input 130, is shown by way of example in Figure 10. The module for determining the limited driving input M100 can be configured not to limit the force input 210 if the force input 210 is less than or equal to zero. Furthermore, the module for determining the limited force input M100 can be configured to limit the force input 210 if the force input 210 is greater than zero. The limited force input 210 can, for example, be the minimum of the force input 210, which is specified, for example, by the driver and / or the automated driving system, and a value that is formed by multiplying a sum of the ambient acceleration 170 and the maximum vehicle acceleration 181 by the vehicle mass 120.

[0101] Furthermore, the module for determining the force reserve M300 can also be configured to process the ambient acceleration 170 directly, for example if the force input 210 is not limited, i.e., for example, if the module for determining the limited force input M100 is not present. For this purpose, the module M300 for determining the force reserve M300 can be configured to calculate the ambient acceleration 170 with the force input M300. For this purpose, for example, the ambient acceleration 170 is first multiplied by the vehicle mass 120 and the force input 210 is added to this value, i.e., the force input 210 is calculated by adding the force input 210 to this value. All further calculation steps for which the module for determining the force reserve M300 is configured according to the invention can then proceed analogously, for example as shown in Figure 8 and described in the associated description.

[0102] List of reference symbols

[0103] 151 minimum resistance forces of the first

[0104] 1 vehicle ten drive systems (for each gear)

[0105] 2 electric motor 152 minimum resistance forces of the two

[0106] 3 gear drive systems (for each gear)

[0107] 4 vehicle axles 155 minimum total resistance force

[0108] 41 first rear axle of the actual gear combination

[0109] 42 second rear axle 160 power reserve

[0110] 43 front axle 161 acceleration reserve

[0111] 100 Control 170 Ambient Acceleration

[0112] 110 Target gear combination 180 Vehicle acceleration or driving

[0113] 111 Actual gear combination tool deceleration

[0114] 112 gear combinations with sufficient181 maximum vehicle acceleration of the total driving force or182 maximum vehicle deceleration total resistance force 200 vehicle speed

[0115] 113 gear combinations with sufficient 201 speeds of the first electric motor of the total drive power (for each gear)

[0116] 114 gear combinations with sufficient 202 speeds of the second electric motor or total resistance force (for each gear)

[0117] 115 Gear combinations with minor changes in the gears of the drive systems 210 Power input 1000 Method for determining a target gear combination

[0118] 120 Vehicle mass M100 Module for determining a limi¬

[0119] 130 Longitudinal force requirement force input

[0120] 140 maximum total drive forces of the M200 module for determining possible gear combinations total drive forces

[0121] 141 maximum drive forces of the first M300 module for determining a drive system (for each gear) power reserve

[0122] 142 maximum drive forces of the second M400 module for determining a target drive system (for each gear) gear combination

[0123] 145 maximum total drive force of the M401 module for determining possible actual gear combinations gear combinations

[0124] 150 minimum total resistance forces M402 Module for determining an optimal possible gear combinations paint gear combination

[0125] M403 Module for forming a hysteresis

Claims

Claims 1. Method for determining a target gear combination (110) for a vehicle (1) with at least two drive systems, wherein each drive system drives a vehicle axle (4) and each of the two drive systems has at least one motor (2) and at least one transmission (3), wherein at least one of the transmissions has at least two gears; wherein the method comprises the following step: Determination of the target gear combination (110) based on a preceding route profile and / or a speed and / or an acceleration of at least one vehicle ahead and / or behind and / or based on a distance to at least one vehicle ahead and / or behind.

2. Method for determining the target gear (110) according to claim 1, wherein the target gear combination is determined based on a comparison of a longitudinal force requirement (130) with maximum total driving forces (140) of possible gear combinations of the at least two gears of the at least two transmissions (3) and / or minimum total resistance forces (150) of possible gear combinations of the at least two gears of the at least two transmissions (3), wherein the maximum total driving forces (140) are the sum of the maximum driving forces (141, 142) of the possible gear combinations and the minimum total resistance forces (150) are the sum of the minimum resistance forces (151, 152) of the possible gear combinations.

3. Method for determining the target gear ratio (110) according to claim 1 or 2, wherein the longitudinal force requirement is determined based on a preceding road profile; and / or wherein the longitudinal force requirement is determined based on a speed and / or an acceleration of at least one preceding and / or following vehicle and / or based on a distance to at least one preceding and / or following vehicle.

4. Method for determining the target gear combination (110) according to one of the preceding claims, wherein, if the longitudinal force requirement (130) is greater than or equal to zero, the target gear combination (110) is determined by comparing the longitudinal force requirement (130) with the maximum total driving forces (140) and otherwise by comparing it with the minimum total resistance forces (150).

5. Method for determining the target gear combination (110) according to one of the preceding claims, wherein, if no maximum total driving force of the maximum where the total driving forces (140) are greater than and / or equal to the longitudinal force requirement (130), the gear combination is selected as the target gear combination which has the maximum total driving force; and / or where, if the maximum total resistance force of the minimum total resistance forces (150) is less than and / or equal to the longitudinal force requirement, the gear combination is selected as the target gear combination which has the minimum total resistance force.

6. Method for determining the target gear combination (110) according to one of the preceding claims, wherein the target gear combination (110) is determined such that a gear combination is selected in which the gear is changed only in the fewest possible number of the at least two transmissions (3) and / or wherein the target gear combination (110) is determined such that a gear is changed in at least one transmission of the at least two transmissions (3).

7. Method for determining the target gear combination (110) according to claim 5, wherein, in several gear combinations in which an equal minimum number of gears is changed in each case, the gear combination is selected which has the smallest maximum total driving force of the maximum total driving forces (140) and / or the largest minimum total resistance force of the minimum total resistance forces (150).

8. Method for determining the target gear combination (110) according to one of the preceding claims, wherein the longitudinal force requirement (130) is determined from a force reserve (160) and a force input (210).

9. Method for determining the target gear combination (110) according to claim 8, wherein the power reserve (160) is determined from an acceleration reserve (161) and a vehicle mass (120).

10. Method for determining the target gear combination (110) according to claim 9, wherein the acceleration reserve (161) is determined from a force utilization (1611) and an acceleration utilization (1612).

11. Method for determining the target gear combination (110) according to claim 10, wherein the acceleration reserve (161) is determined from a characteristic map (1613) which has a value for each force utilization (1611) and acceleration utilization, wherein, if the force input (210) is greater than or equal to zero, the value is multiplied by a maximum vehicle acceleration (180) and / or otherwise the value is multiplied by a maximum vehicle deceleration (190).

12. Method for determining the target gear combination (110) according to claim 11, wherein, if the force input (210) is greater than or equal to zero, the force utilization is determined from a ratio of the force input (210) to a maximum total driving force (140) of an actual gear combination. (111) of the at least two transmissions (3) is determined and / or otherwise the power utilization is determined from a ratio of the force input (210) to a maximum total resistance force (140) of the actual gear combination (111) of the at least two transmissions (3); and / or wherein, if the force input (210) is greater than and / or equal to zero, the acceleration utilization is determined from a ratio of a vehicle acceleration (180) to the maximum vehicle acceleration (181) and / or otherwise the acceleration utilization is determined from a ratio of a vehicle deceleration (180) to the maximum vehicle deceleration (182).

13. Method for determining the target gear combination (110) according to one of claims 9 to 12, wherein the acceleration reserve is determined based on a preceding route profile and / or wherein the acceleration reserve is determined based on a speed and / or an acceleration of at least one preceding and / or following vehicle and / or based on a distance to at least one preceding and / or following vehicle.

14. Method for determining the target gear combination (110) according to one of claims 9 to 13, where the force input (210) is limited.

15. Method for determining the target gear combination (110) according to claim 14, wherein the limited force input (210) is determined from the minimum of the force input (210) and a sum of a resistance acceleration (170) and the maximum vehicle acceleration (181) times the vehicle mass (120).

16. Non-volatile, computer-readable storage medium for physically storing computer program instructions that can be executed by a processor, wherein the computer program instructions define the method according to any of the preceding claims.

17. Vehicle (1) with at least two drive systems, each drive system being designed to drive one vehicle axle (4) and each drive system comprising: an electric motor (2) and at least one transmission (3) with at least two gears, the electric motor (2) being operatively connected to the transmission (3); and a control system configured to execute the method according to any one of the preceding claims 1-15.

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