Device and method for the variable distribution of wheel torques of a motor vehicle having two drive axles

Abstract

Device (50) for the variable distribution of wheel torques of a motor vehicle having two drive axles, comprising: - a drive control device (100) which is designed to set drive torques (MA-VA, MA-HA) of the two drive axles by controlling at least two drive components (110, 120, 130, 140, 150) of the two drive axles, wherein an upper limit (MAV100) and a lower limit (MAV200) and thus the achievable drive torque range can be determined taking into account the current driving state and the currently achievable performance data of the drive components (110, 120, 130, 140, 150); - a brake control device (300) which is designed to adjust braking torques (MB-VA, MB-HA) of the two drive axles by controlling a respective brake system component (310, 320) of the two drive axles, wherein an upper limit (MBV100) and a lower limit (MBV200) and thus the achievable braking torque range can be determined taking into account the current driving condition and the currently achievable performance data of the brake system components (310, 320); and - an axle torque control device (200) which is coupled to the drive control device (100) and the brake control device (200) and which is designed to variably distribute the wheel torques of the motor vehicle, which are predominant as drive torques (MA-VA, MA-HA) or braking torques (MA-VA, MA-HA), to the two drive axles as a function of a degree of actuation of a brake pedal (30) or an accelerator pedal (10), wherein an upper limit (MAV120) and a lower limit (MAV220), an upper limit (MAH120) and a lower limit (MAH220) of a predetermined drive torque range, an upper limit (MBV120) and a lower limit (MBV220) and an upper limit (MBH120) and a lower limit (MBH220) of a predetermined braking torque range can be determined by the axle torque control device (200).

Description

[0001] The present invention relates to a device for the variable distribution of wheel torques of a motor vehicle having two drive axles and a corresponding method.

[0002] DE 10 2008 054 847 A1 describes a braking system for a motor vehicle, with a hydraulic muscle or auxiliary power braking system, which has a master brake cylinder which can be actuated by muscle power and to which at least one hydraulic wheel brake is connected, wherein the braking system has an external power braking system with an externally energy-operated hydraulic pressure source to which at least one hydraulic wheel brake is connected.Furthermore, a method for controlling the actuation of a brake system for a motor vehicle is described, wherein a hydraulic muscle or auxiliary power brake system is controlled by a muscle-power actuated master brake cylinder to which at least one hydraulic wheel brake is connected, wherein the brake system has an external power brake system with an externally powered hydraulic pressure source to which at least one hydraulic wheel brake is connected, and wherein the muscle or auxiliary power brake system is controlled to a constant pedal characteristic curve.

[0003] US 2011 / 0192661 A1 describes a method for operating a braking system of a hybrid vehicle powered by an internal combustion engine and an electric motor, in which a braking pressure for a mechanical brake of the braking system is reduced during braking with recuperation compared to the braking pressure during braking without recuperation. Furthermore, the method described therein relates to such a braking system and a vehicle with such a braking system.

[0004] US 6 634 724 B2 describes a braking device and a corresponding control system.

[0005] US 2008 / 0116740 A1 describes a braking system with force feedback.

[0006] US 2011 / 0291470 A1 describes an electro-hydraulic braking system and a corresponding method for operating the electro-hydraulic braking system.

[0007] DE 10 2005 014 801 A1 discloses a braking system for preventing a motor vehicle from rolling away.

[0008] DE 102 25 873 A1 describes a drive force distribution device in which the drive force acting on the wheels of a motor vehicle can be adjusted depending on an accelerator pedal or brake pedal.

[0009] The object of the present invention is therefore to provide an improved device and an improved method for variable torque distribution of independent drive and braking torques of a motor vehicle.

[0010] This object is achieved by a device for the variable distribution of wheel torques of a motor vehicle having two drive axles according to patent claim 1 and by a method for the variable distribution of wheel torques of a motor vehicle having two drive axles with the features of patent claim 8.

[0011] The present invention provides a device for the variable distribution of wheel torques of a motor vehicle having two drive axles, comprising: a drive control device which is designed to adjust drive torques of the two drive axles by controlling at least two drive components of the two drive axles, wherein an upper limit and a lower limit and thus the achievable drive torque range can be determined taking into account the current driving condition and the currently achievable performance data of the drive components;a brake control device which is designed to adjust braking torques of the two drive axles by controlling a respective brake system component of the two drive axles, wherein an upper limit and a lower limit and thus the achievable braking torque range can be determined taking into account the current driving condition and the currently achievable performance data of the brake system components;and an axle torque control device which is coupled to the drive control device and the brake control device and which is designed to variably distribute the wheel torques of the motor vehicle, which prevail as drive torques or braking torques, to the two drive axles as a function of the degree of actuation of a brake pedal or an accelerator pedal, wherein an upper limit and a lower limit, an upper limit and a lower limit of a predetermined drive torque range, an upper limit and a lower limit, and an upper limit and a lower limit of a predetermined braking torque range can be determined by the axle torque control device.

[0012] Furthermore, the present invention provides a method for the variable distribution of wheel torques of a motor vehicle having two drive axles, comprising the method steps: detecting a degree of actuation of an accelerator pedal and / or a brake pedal by an axle torque control device and determining two drive torque ranges for wheel torques of the two drive axles of the motor vehicle that prevail as drive torques and / or two brake torque ranges for wheel torques that prevail as brake torques;Controlling a drive control device and / or a brake control device with the axle torque control device and controlling drive components and / or brake system components of the two drive axles by the drive control device and / or the brake control device in order to adjust the drive torques and the brake torques of the drive axles within the two drive torque ranges and the two brake torque ranges and thereby variably distribute the wheel torques of the motor vehicle to the two drive axles depending on the degree of actuation of the brake pedal or the accelerator pedal;

[0013] One idea of the present invention is to create a variably adjustable torque distribution of drive and / or braking torques from independent drive components or independent braking system components between two drive axles of the motor vehicle.

[0014] The device according to the invention advantageously allows for an increase in the energy efficiency of the motor vehicle's drive system through an optimized distribution of drive and braking torques to the drive axles of the motor vehicle by controlling the drive and braking system components of the motor vehicle. Furthermore, this advantageously allows for improved driving dynamics and increased lateral and longitudinal acceleration of the motor vehicle.

[0015] Preferred developments of the invention are the subject of the dependent claims.

[0016] According to an advantageous development of the invention, one of the drive components is designed as an electric motor, an internal combustion engine, a direct transmission, or an axle drive. Advantageously, the device for variable wheel torque distribution can control any drive component regardless of the specific design of the drive components of the motor vehicle.

[0017] According to a further advantageous development of the invention, one of the braking system components is designed as a regenerative and anti-dazzle braking system or as an electronic stability control system. This advantageously allows for the recovery of the kinetic energy of the motor vehicle and a reduction in wear on the hydraulic brakes of the motor vehicle.

[0018] According to a further advantageous development of the invention, the regenerative and dazzling braking system comprises a regenerative brake comprising an electric motor operating as a generator. This enables efficient recovery of the motor vehicle's kinetic energy.

[0019] According to a further advantageous development of the invention, the regenerative and blendable braking system comprises a hydraulic braking system. This advantageously allows the transition from regenerative to hydraulic braking of the braking system components to be blended without causing deceleration fluctuations that would be disturbing to the driver of the motor vehicle.

[0020] According to a further advantageous development of the invention, the two drive axles are designed as a front axle and a rear axle.

[0021] According to a further advantageous development of the invention, the two drive axles each have two edges at which the wheel torques of the motor vehicle are predominant.

[0022] The described designs and further training courses can be combined with each other as required, where appropriate.

[0023] Further possible embodiments, developments and implementations of the invention also include combinations of features of the invention described previously or below with regard to the exemplary embodiments that are not explicitly mentioned.

[0024] The accompanying drawings are intended to provide a further understanding of embodiments of the invention. They illustrate embodiments and, in conjunction with the description, serve to explain principles and concepts of the invention.

[0025] Other embodiments and many of the aforementioned advantages will become apparent upon review of the drawings. The elements shown in the drawings are not necessarily drawn to scale. In the drawings: Fig. 1 is a schematic representation of a device for the variable distribution of wheel torques of a motor vehicle having two drive axles according to an embodiment of the invention; Fig. 2 a schematic representation of a diagram with a function graph showing the dependence of the traction utilization on the frequency of an operating state according to an embodiment of the invention; Fig. 3 a schematic representation of a diagram with a function graph for the temporal dependence of a drive torque applied to a front axle of the motor vehicle according to an embodiment of the invention; Fig. 4 a schematic representation of a diagram with a function graph for the temporal dependence of a drive torque applied to a rear axle of the motor vehicle according to an embodiment of the invention; Fig. 5 is a schematic representation of a diagram with a function graph for the temporal dependence of a braking torque applied to a front axle of the motor vehicle according to an embodiment of the invention; Fig. 6 is a schematic representation of a diagram with a function graph for the temporal dependence of a braking torque applied to a rear axle of the motor vehicle according to an embodiment of the invention; Fig. 7-8 each show a flowchart of a method for the variable distribution of wheel torques of a motor vehicle having two drive axles according to a further embodiment of the invention; and Fig. 9-10 each show a flow chart of a method for the variable distribution of wheel torques of a motor vehicle having two drive axles according to a further embodiment of the invention.

[0026] In the figures of the drawing, the same reference symbols designate the same or functionally identical elements, parts, components or process steps, unless otherwise stated.

[0027] The Fig. 1 shows a schematic representation of a device for the variable distribution of wheel torques of a motor vehicle having two drive axles according to an embodiment of the invention.

[0028] A device 50 for the variable distribution of wheel torques of a motor vehicle having two drive axles comprises a drive control device 100, a brake control device 300 and an axle torque control device 200.

[0029] The drive control device 100 is designed to adjust drive torques MA-VA, MA-HA of the two drive axles by controlling at least two drive components 110, 120, 130, 140, 150 of the two drive axles.

[0030] For example, the drive components 110, 120, 130, 140, 150 of the drive control device 100 are divided into a first drive component group 100a of drive components 110, 120 of the front axle and a second drive component group 100b of drive components 130, 140, 150 of the rear axle.

[0031] For example, the drive components 110, 120, 130, 140, 150 are designed as an electric motor 110, 140 or as an internal combustion engine 150 or as a direct transmission 130 or as an axle transmission 120.

[0032] The axle torque control device 200 is coupled, for example, to the drive control device 100 and the brake control device 300 and is designed to variably distribute the wheel torques of the motor vehicle prevailing as drive torques MA-VA, MA-HA or brake torques MA-VA, MA-HA to the two drive axles depending on the degree of actuation of a brake pedal 30 or an accelerator pedal 10.

[0033] The axle torque control device 200 comprises, for example, a drive torque control device 210 and a brake torque control device 230. A switching control device 220 of the axle torque control device 200 is coupled to the drive torque control device 210 and the brake torque control device 230 and controls the switching between the two control devices depending on the actuation of the accelerator pedal 10 and the brake pedal 30.

[0034] The brake control device 300 is designed, for example, to adjust braking torques MB-VA, MB-HA of the two drive axles by controlling a respective brake system component 310, 320 of the two drive axles.

[0035] The braking system components 310, 320 can be designed as a regenerative and dazzling braking system 320 or as an electronic stability control system 310.

[0036] The brake control device 300 can be used, for example, for all brake circuit configurations and drive concepts. The respective braking torques MB-VA, MB-HA of the drive axles and the transition from regenerative to hydraulic braking of the brake system components 310, 320 are blended by the brake control device 300 without disruptive deceleration fluctuations.

[0037] The braking torque blending is carried out by the brake control device 300 on both drive axles.

[0038] The Fig. 2 shows a schematic representation of a diagram with a function graph for the dependence of the traction utilization on the frequency of an operating state according to an embodiment of the invention.

[0039] On the x-axis of the Fig. In the diagram shown in Figure 2, a frequency of an operating condition is plotted, the y-axis represents the traction utilization or a weight.

[0040] There are three different value ranges on the y-axis of the Fig. 2, which correspond to three different weighting ranges. Different control components are assigned to the weighting ranges. For example, driving stability is assigned an electronically controlled driver assistance system as the highest value range, driving dynamics is assigned an all-wheel drive control system as the middle value range, and energy efficiency is assigned a powertrain management system as the lowest value range.

[0041] The Fig. 3 shows a schematic representation of a diagram with a function graph for the temporal dependence of a drive torque applied to a front axle of the motor vehicle according to an embodiment of the invention.

[0042] On the y-axis of the Fig. The diagram shown in Figure 3 shows a drive torque MA-VA applied to a front axle of the motor vehicle, the x-axis represents the time t.

[0043] An upper limit MAV100 and a lower limit MAV200 of an achievable drive torque range are plotted as a dashed line on the y-axis. The upper limit MAV100 and the lower limit MAV200, and thus the achievable drive torque range, are determined taking into account the current driving condition and the currently achievable performance data of drive components 110, 120, 130, 140, and 150.

[0044] An upper limit MAV120 and a lower limit MAV220 of a predefined drive torque range are determined by the axle torque control device 200. The upper limit MAV120 and the lower limit MAV220 are plotted as a dotted line on the y-axis. The predefined drive torque range is determined as a function of a drive torque desired by the driver and a distribution calculated by the axle torque control device 200.

[0045] Within the specified drive torque range, the drive control device 100 determines an actual torque MAV of the drive torque of the front axle at a time t1. At a time t2, for example, the actual torque MAV of the drive torque of the front axle is reduced due to a changed driver command.

[0046] The Fig. 4 shows a schematic representation of a diagram with a function graph for the temporal dependence of a drive torque applied to a rear axle of the motor vehicle according to an embodiment of the invention.

[0047] On the y-axis of the Fig. The diagram shown in Figure 4 shows a drive torque MA-HA applied to a rear axle of the motor vehicle, the x-axis represents the time t.

[0048] An upper limit MAH100 and a lower limit MAH200 of an achievable drive torque range of the rear axle are plotted as a dashed line on the y-axis. The upper limit MAH100 and the lower limit MAH200, and thus the achievable drive torque range of the rear axle, are determined taking into account the current driving conditions and the performance data of drive components 110, 120, 130, 140, and 150.

[0049] An upper limit MAH120 and a lower limit MAH220 of a predefined drive torque range of the rear axle are determined by the axle torque control device 200. The upper limit MAH120 and the lower limit MAH220 are plotted as a dotted line on the y-axis. The predefined drive torque range is determined as a function of a drive torque desired by the driver and a distribution calculated by the axle torque control device 200. In particular, the required interfaces are reduced if the upper limit MAH120 and the lower limit MAH220 are determined by the drive control device 100 from the specifications of the front axle, in conjunction with the drive torque desired by the driver.

[0050] Within the specified drive torque range, the drive control device 100 determines an actual torque MAH of the drive torque of the rear axle at a time t1. At a time t2, the actual torque MAH of the drive torque of the rear axle is reduced, for example, due to a changed driver command.

[0051] The Fig. 5 shows a schematic representation of a diagram with a function graph for the temporal dependence of a braking torque applied to a front axle of the motor vehicle according to an embodiment of the invention.

[0052] On the y-axis of the Fig. The diagram shown in Figure 5 shows a braking torque MB-VA applied to a front axle of the motor vehicle, the x-axis represents the time t.

[0053] An upper limit MBV100 and a lower limit MBV200 of an achievable braking torque range are plotted as a dashed line on the y-axis. The upper limit MBV100 and the lower limit MBV200, and thus the achievable braking torque range, are determined taking into account the current driving condition and the currently achievable performance data of the braking system components 310, 320.

[0054] An upper limit MBV120 and a lower limit MBV220 of a predetermined braking torque range of the front axle are determined by the axle torque control device 200. The upper limit MBV120 and the lower limit MBV220 are plotted as a dotted line on the y-axis.

[0055] Within the specified braking torque range, the brake control device 300 determines an actual torque MBV of the braking torque of the front axle at a time t1. At a time t2, for example, the actual torque MBV of the braking torque of the front axle is reduced due to a changed driver command.

[0056] The Fig. 6 shows a schematic representation of a diagram with a function graph for the temporal dependence of a braking torque applied to a rear axle of the motor vehicle according to an embodiment of the invention.

[0057] On the y-axis of the Fig. The diagram shown in Figure 6 shows a braking torque MB-HA applied to a rear axle of the motor vehicle, the x-axis represents the time t.

[0058] An upper limit MBH100 and a lower limit MBH200 of an achievable braking torque range of the rear axle are plotted as a dashed line on the y-axis. The upper limit MBH100 and the lower limit MBH200, and thus the achievable braking torque range of the rear axle, are determined taking into account the current driving condition and the performance data of the braking system components 310, 320.

[0059] An upper limit MBH120 and a lower limit MBH220 of a specified braking torque range of the rear axle are determined by the brake control device 300. The upper limit MBH120 and the lower limit MBH220 are plotted as a dotted line on the y-axis. The required interfaces are reduced if the upper limit MBH120 and the lower limit MBH220 are determined by the drive control device 100 from the specifications of the front axle, in conjunction with the drive torque desired by the driver.

[0060] Within the specified braking torque range, the brake control device 300 determines an actual torque MBH of the braking torque of the rear axle at a time t1. At a time t2, for example, the actual torque MBH of the braking torque of the rear axle is reduced due to a changed driver command.

[0061] The Fig. 7 shows a flowchart of a method for the variable distribution of wheel torques of a motor vehicle having two drive axles according to a further embodiment of the invention.

[0062] As a first method step, a degree of actuation of a brake pedal 30 is detected S11 by an axle torque control device 200 and two braking torque ranges are determined for wheel torques of the two drive axles of the motor vehicle that prevail as braking torques.

[0063] As a second method step, a brake control device 300 is controlled S12 by the axle torque control device 200 and brake system components 310, 320 of the two drive axles are controlled by the brake control device 300 in order to adjust the respective braking torques of the drive axles within the two braking torque ranges and thereby distribute the wheel torques of the motor vehicle variably between the two drive axles.

[0064] The Fig. 8 shows a flowchart of a further method for the variable distribution of wheel torques of a motor vehicle having two drive axles according to a further embodiment of the invention.

[0065] As a first method step, S11a detects two achievable braking torque ranges taking into account the current driving state. For example, a first achievable braking torque range is assigned to the front axle of the motor vehicle, and a second achievable braking torque range is assigned to the rear axle of the motor vehicle.

[0066] As a second method step, a detection S11b of a degree of actuation of a brake pedal 30 is carried out by an axle torque control device 200.

[0067] As a third method step, S11c determines a first predetermined braking torque range of the front axle, which lies within the first achievable braking torque range, and a second predetermined braking torque range of the rear axle, which lies within the second achievable braking torque range, depending on the determined degree of actuation of the brake pedal 30 as the braking acceleration desired by the driver. The two predetermined braking torque ranges, when added together, correspond to the braking acceleration desired by the driver.

[0068] As a fourth method step, S12a of a brake control device 300 is controlled by the axle torque control device 200.

[0069] As a fifth method step, braking system components 310, 320 of the two drive axles are controlled by the brake control device 300 in order to set the respective braking torques MB-VA, MB-HA of the drive axles within the two predetermined braking torque ranges as actual torques of the drive axles.

[0070] As a sixth process step, the wheel torques of the motor vehicle are distributed S12c.

[0071] The Fig. 9 shows a flowchart of a method for the variable distribution of wheel torques of a motor vehicle having two drive axles according to a further embodiment of the invention.

[0072] As a first method step, a degree of actuation of an accelerator pedal is detected S21 by an axle torque control device 200 and two drive torque ranges for wheel torques of the two drive axles of the motor vehicle that prevail as drive torques are determined.

[0073] As a second method step, a drive control device with the axle torque control device 200 is activated S22 and drive components 110, 120, 130, 140, 150 of the two drive axles are activated by the drive control device in order to set the respective drive torques MA-VA, MA-HA of the drive axles within the two drive torque ranges and thereby distribute the wheel torques of the motor vehicle variably between the two drive axles.

[0074] The Fig. 10 shows a flowchart of a further method for the variable distribution of wheel torques of a motor vehicle having two drive axles according to a further embodiment of the invention.

[0075] As a first method step, S21a detects two possible drive torque ranges taking into account the current driving state. For example, a first achievable drive torque range is assigned to the front axle of the motor vehicle, and a second achievable drive torque range is assigned to the rear axle of the motor vehicle.

[0076] As a second method step, a detection S21b of a degree of actuation of an accelerator pedal 10 is carried out by an axle torque control device 200.

[0077] As a third method step, S21c determines a first predetermined drive torque range of the front axle, which lies within the first achievable drive torque range, and a second predetermined drive torque range of the rear axle, which lies within the second achievable drive torque range, depending on the determined degree of actuation of the accelerator pedal as the acceleration desired by the driver. The two predetermined drive torque ranges, when added together, correspond to the acceleration desired by the driver.

[0078] As a fourth method step, S22a is used to control a drive control device 100 with the axle torque control device 200.

[0079] As a fifth method step, drive components 110, 120, 130, 140, 150 of the two drive axles are controlled S22b by the drive control device 100 in order to set the respective drive torques MA-VA, MA-HA of the drive axles within the two predetermined drive torque ranges as actual torques.

[0080] As a sixth process step, the wheel torques of the motor vehicle are distributed S22c.

Claims

[1] Device (50) for the variable distribution of wheel torques of a motor vehicle having two drive axles, comprising: - a drive control device (100) which is designed to set drive torques (MA-VA, MA-HA) of the two drive axles by controlling at least two drive components (110, 120, 130, 140, 150) of the two drive axles, wherein an upper limit (MAV100) and a lower limit (MAV200) and thus the achievable drive torque range can be determined taking into account the current driving state and the currently achievable performance data of the drive components (110, 120, 130, 140, 150); - a brake control device (300) which is designed to adjust braking torques (MB-VA, MB-HA) of the two drive axles by controlling a respective brake system component (310, 320) of the two drive axles, wherein an upper limit (MBV100) and a lower limit (MBV200) and thus the achievable braking torque range can be determined taking into account the current driving condition and the currently achievable performance data of the brake system components (310, 320); and - an axle torque control device (200) which is coupled to the drive control device (100) and the brake control device (200) and which is designed to variably distribute the wheel torques of the motor vehicle, which are predominant as drive torques (MA-VA, MA-HA) or braking torques (MA-VA, MA-HA), to the two drive axles as a function of a degree of actuation of a brake pedal (30) or an accelerator pedal (10), wherein an upper limit (MAV120) and a lower limit (MAV220), an upper limit (MAH120) and a lower limit (MAH220) of a predetermined drive torque range, an upper limit (MBV120) and a lower limit (MBV220) and an upper limit (MBH120) and a lower limit (MBH220) of a predetermined braking torque range can be determined by the axle torque control device (200). [2] Device (50) according to claim 1, characterized bythat one of the drive components (110, 120, 130, 140, 150) is designed as an electric motor (110, 140) or as an internal combustion engine (150) or as a direct transmission (130) or as an axle transmission (120). [3] Device (50) according to claim 1 or 2, characterized by that one of the braking system components (310, 320) is designed as a recuperation and dazzling braking system (320) or as an electronic stability control system (310). [4] Device (50) according to claim 3, characterized by that the recuperative and dazzling braking system (320) has a recuperative brake which comprises an electric motor operated as a generator. [5] Device (50) according to one of claims 3 and 4, characterized by that the recuperative and dazzling braking system (320) has a hydraulic braking system. [6] Device (50) according to one of the preceding claims, characterized bythat the two drive axles are designed as a front axle and a rear axle. [7] Device (50) according to one of the preceding claims, characterized by that the two drive axles each have two edges at which the wheel torques of the motor vehicle predominate. [8] Method for the variable distribution of wheel torques of a motor vehicle having two drive axles with a device (50) according to one of the preceding claims, comprising the method steps: - detecting (S11; S21) a degree of actuation of an accelerator pedal (10) and / or a brake pedal (30) by an axle torque control device (200) and determining two drive torque ranges for wheel torques of the two drive axles of the motor vehicle prevailing as drive torques (MA-VA, MA-HA) and / or two braking torque ranges for wheel torques of the two drive axles of the motor vehicle prevailing as braking torques (MB-VA, MB-HA); - controlling (S12; S22) a drive control device (100) and / or a brake control device (300) with the axle torque control device (200) and controlling drive components (110, 120, 130, 140, 150) and / or brake system components (310, 320) of the two drive axles by the drive control device (100) and / or the brake control device (200) in order to adjust the drive torques (MA-VA, MA-HA) and the brake torques (MB-VA, MB-HA) of the drive axles within the two drive torque ranges and the two brake torque ranges and thereby distribute the wheel torques of the motor vehicle variably between the two drive axles depending on the degree of actuation of the brake pedal (30) or the accelerator pedal (10).

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