METHOD FOR OPERATING AN ELECTRIC BICYCLE

Description

State of the art

[0001] The present invention relates to a method for operating an electric bicycle, as well as an electric bicycle.

[0002] Electric bicycles are known to have hydraulic braking systems that feature actuators that can be used to generate brake pressure in the braking system in a controlled manner. For example, such an actuator can be part of an anti-lock braking system. Often, the purpose is to prevent the vehicle's wheels from locking by modulating the hydraulic brake pressure in the system.

[0003] Document DE 10 2020 215569 A1 discloses the features of the preamble of claim 1. Disclosure of the invention

[0004] The method according to the invention with the features of claim 1 is characterized in that a particularly flexible and efficient driving operation of the electric bicycle can be provided. In particular, a particularly high level of riding comfort can be enabled for a rider of the electric bicycle. This is achieved according to the invention by a method for operating an electric bicycle, wherein the electric bicycle has a braking system and a controllably actuated drive unit. In particular, the drive unit is configured to provide a motor torque in response to pedal actuation by the rider in order to motor-assist the rider's pedaling force. The braking system has a controllably actuated actuator in order to be able to generate a braking torque in a controlled manner. The braking system is preferably designed as a hydraulic braking system. The method comprises the steps: controlled generation of a braking torque by means of the braking system, and controlled generation of a drive torque by means of the drive unit.

[0005] The controlled generation of the braking torque and the controlled generation of the drive torque are performed simultaneously and are dependent on one another in such a way that the electric bicycle decelerates with a predetermined total braking torque or accelerates the electric bicycle with a predetermined total drive torque. Preferably, a braking torque and a drive torque each greater than zero are generated simultaneously during the method.

[0006] In other words, the method provides coordinated control of braking torque and drive torque in dependence on one another. This makes it possible to provide a particularly high level of flexibility in the operation of the electric bicycle. For example, a particularly large torque range can be covered by the controlled regulation during the operation of the electric bicycle. This means that, for example, acceleration or deceleration of the electric bicycle can be achieved flexibly through the corresponding coordinated control of the braking system and drive unit, in particular without active intervention by the rider being required, for example by means of actuating the brake lever. This means that a multitude of automatic riding functions can be provided in a simple and efficient manner, enabling a particularly high level of riding comfort for the rider of the electric bicycle.

[0007] The subclaims contain preferred developments of the invention.

[0008] Preferably, in a first operating mode, the actuator of the braking system is actuated in such a way as to generate a predetermined constant braking torque. This means, in particular, that a constant braking pressure is generated in the braking system by means of the actuator. This makes it possible to shift the operating range of the drive unit overall towards lower torques. This means that, simply by adjusting the drive torque that can be provided by the drive unit, a torque range can be covered that allows both acceleration and deceleration of the electric bicycle. For example, the deceleration of the electric bicycle can be achieved by reducing the drive torque of the drive unit to a lower value than the constant braking torque generated by the braking system. Thus, a particularly high level of flexibility in the operation of the electric bicycle can be provided through particularly simple and effective control.In particular, advantageous driving functions can be provided in a simple manner, which can be implemented solely by controlling the drive unit. For example, traction control and / or preventing or mitigating the effects of a front wheel of the electric bicycle lifting can be provided in a particularly simple manner.

[0009] Particularly preferably, the predetermined constant braking torque corresponds to at least 10%, preferably at most 80%, preferably at least 30%, particularly preferably at most 60%, of a maximum drive torque that can be generated by the drive unit. This ensures that, by controlling the drive unit alone, a torque range can be covered that also enables sufficient deceleration of the electric bicycle for a variety of riding functions.

[0010] Preferably, the predetermined constant braking torque is generated independently of a brake lever force on a brake lever of the electric bicycle. In particular, the brake lever is provided to enable manual generation of braking pressure in the braking system. This means that the constant braking torque is generated in the first operating mode even when the brake lever is not actuated. This allows for a fully automated function that allows both acceleration and deceleration of the electric bicycle.

[0011] More preferably, the method further comprises the step of detecting wheel slip, preferably of a driven or drivable wheel of the electric bicycle, in particular a rear wheel. The controlled generation of the drive torque provided by the drive unit is carried out as a function of the detected wheel slip. Preferably, the drive torque of the drive unit is reduced if the detected wheel slip exceeds a predetermined wheel slip limit. In other words, traction control can be carried out by the corresponding controlled actuation of the drive unit, in particular in such a way as to reduce the wheel slip.Particularly in combination with a constant brake pressure generated by the braking system, targeted braking of the spinning wheel can be achieved actively and automatically, thus providing particularly effective traction control in a wide variety of driving situations.

[0012] Particularly preferably, the method further comprises the step of detecting a pitch angle of the electric bicycle. A pitch angle is considered, in particular, to be a deflection of the electric bicycle about a transverse axis, which may, for example, be parallel to a bottom bracket axis. The controlled generation of the drive torque is carried out as a function of the detected pitch angle. Preferably, the drive torque of the drive unit is reduced if the detected pitch angle exceeds a predetermined pitch angle limit. This can, for example, prevent a front wheel of the electric bicycle from lifting off or mitigate its effect. This means, for example, that wheelie prevention can be provided.Alternatively, preferably to a comparison of the detected pitch angle, a change in the pitch angle can also be determined, for example, wherein the drive torque is preferably reduced if the change in the pitch angle exceeds a predetermined limit value.

[0013] Preferably, in a second operating mode, the controlled generation of the braking torque and the controlled generation of the drive torque occur in such a way as to keep the electric bicycle stationary. This means that the braking torque and drive torque are coordinated in such a way that the electric bicycle is held stationary, preferably exclusively by the braking torque and drive torque. In particular, this means that, even on uphill or downhill gradients, no manual braking or pedaling by the electric bicycle rider is required to keep the electric bicycle stationary. This makes it possible to provide a particularly high level of riding comfort for the rider when operating the electric bicycle.

[0014] Preferably, the method further comprises the step of detecting an inclination of the electric bicycle, in particular relative to a horizontal plane. The controlled generation of the braking torque and the controlled generation of the drive torque are carried out as a function of the detected inclination. This enables automatic stopping of the electric bicycle on an incline or decline in a particularly simple and effective manner.

[0015] Preferably, the controlled generation of the braking torque and the controlled generation of the drive torque are additionally carried out as a function of a total weight of the electric bicycle. In particular, the total weight is considered to be at least the dead weight of the electric bicycle, and additionally the weight of the rider and any load on the electric bicycle. Preferably, based on the total weight and the detected incline, a required drive torque and / or braking torque is determined in order to hold the electric bicycle stationary on the corresponding incline. For example, the total weight can be entered manually by the rider of the electric bicycle. This makes it possible in a particularly simple and efficient manner for the electric bicycle to be held on inclines or declines through the automatic operation of the braking system and drive unit.

[0016] Particularly preferably, the method further comprises the step of controlled reduction of a brake pressure generated by the brake system in response to pedal actuation. The brake pressure is reduced in such a way that the electric bicycle is accelerated by the drive torque generated by the drive unit. This means that through the coordinated control of drive torque and braking torque, with the braking torque being adjusted in particular by reducing the brake pressure, an automatic start of the electric bicycle from a standstill, for example, on an incline, is initiated when the rider actuates the pedal of the electric bicycle.

[0017] More preferably, the method further comprises the step of detecting a pitch angle of the electric bicycle. The pitch angle is considered to be, in particular, a deflection of the electric bicycle about a transverse axis, which may be parallel to a bottom bracket axis, for example. The controlled generation of the braking torque and / or the controlled generation of the drive torque is carried out as a function of the detected pitch angle. Preferably, the drive torque is reduced and / or the braking torque is increased if the detected pitch angle exceeds a predetermined pitch angle limit. Alternatively, preferably, a change in the pitch angle can be determined, wherein preferably the drive torque is reduced and / or the braking torque is increased if the change in the pitch angle exceeds a predetermined limit.This makes it possible, for example, to simply and effectively prevent the front wheel of an electric bike from lifting off, or to mitigate its impact. This means, for example, that wheelie prevention can be provided when the electric bike starts moving.

[0018] Furthermore, the invention leads to an electric bicycle comprising a braking system, preferably a hydraulic braking system, wherein in particular the braking system comprises a controllably actuatable actuator, a drive unit which is in particular designed to be controllably actuatable, and a control unit which is configured to carry out the described method. Short description of the drawings

[0019] The invention is described below using exemplary embodiments in conjunction with the figures. In the figures, functionally identical components are identified by the same reference numerals. Here: Figure 1 is a simplified schematic view of an electric bicycle in which a method according to a preferred embodiment of the invention is carried out, Figure 2 is a simplified schematic view of torque diagrams which are used in carrying out the method according to the preferred embodiment of the invention, and Figure 3 is a simplified schematic of the electric bicycle of the Figure 1 during the implementation of the method according to the preferred embodiment of the invention on an incline. Preferred embodiments of the invention

[0020] Figure 1shows a simplified schematic view of an electric bicycle 100 in which a method according to a preferred embodiment of the invention is performed. The electric bicycle 100 comprises a drive unit 20 configured to assist a rider's pedaling power using motor power. The drive unit 20 is supplied with electrical energy by an electrical energy storage device 106.

[0021] The electric bicycle 100 comprises a hydraulic braking system 10 by means of which brakes 101, 102 can be actuated on a front wheel 107 and a rear wheel 108, respectively, of the electric bicycle 100. The hydraulic braking system 10 comprises an anti-lock braking unit 1, which is also supplied with electrical energy from the electrical energy storage device 106.

[0022] The anti-lock braking unit 1 comprises an actuator 5, by means of which a hydraulic brake pressure in the brake system 10 can be controllably changed. In particular, a brake pressure in the brake system 10 can be changed by means of the actuator 5 independently of an actuation of a brake lever 19 of the brake system 10. This means, in particular, a brake pressure can be built up and thus a braking torque generated without actuating the brake lever 19. In addition, a brake pressure in the brake system 10 and thus the braking torque can preferably be reduced even while a manual actuation of the brake lever 19 is taking place.

[0023] The electric bicycle 100 further comprises a control unit 30 configured to implement the method according to the invention. The control unit 30 can be used to perform the controlled actuation of the actuator 5 and the controlled actuation of the drive unit 20.

[0024] The method comprises at least two operating modes, which can be carried out, for example, simultaneously or alternatively independently of one another.

[0025] In a first operating mode, a predetermined constant braking torque is generated by the braking system 10, preferably during a ride of the electric bicycle 10. At the same time, a drive torque is generated by the drive unit 20 as a function of a pedal force manually generated by the rider of the electric bicycle 100.

[0026] The first operating mode is determined by the Figure 2 illustrated and described in detail below. Figure 2shows a simplified schematic view of torque diagrams 50, 50', which are used in implementing the method according to the preferred embodiment of the invention. In each of the torque diagrams 50, 50', a torque 51 is shown as a function of a speed 52 of the electric bicycle 100. Line 55 indicates a torque of zero.

[0027] A first torque diagram 50, in which Figure 2left, shows a simplified schematic view of normal operation without performing the method. The two lines 57a show a maximum value and a minimum value of a drive torque that can be generated by the drive unit 20. Between the two lines 57a there is thus a torque range 57 that can be provided to the drive of the electric bicycle 100 by the controlled actuation of the drive unit 20. This torque range 57 extends from the zero line 55 exclusively to positive torques 51.

[0028] When carrying out the first operating mode of the method, that is, when a constant braking torque 53 is provided by means of the braking system 10, the Figure 2 The second torque diagram 50' shown on the right can be provided. As shown in the Figure 2As can be seen, the torque range 57', which essentially corresponds to the working range of the drive unit 20 (cf. torque range 57 in the first torque diagram 50), is shifted relatively downwards by the constant braking torque 53. This means that by varying the controlled actuation of the drive unit 20, negative total torques 51 can also be provided on the electric bicycle 100 in this case.

[0029] This allows advantageous driving functions of the electric bicycle 100, such as traction control in particular, to be provided in an improved manner. This is described in the Figure 2 illustrated by the further torque range 56. This torque range 56 indicates an optimal range for performing traction control on the rear wheel 108 of the electric bicycle 100. As shown in the Figure 2As can be seen, the torque range 56 also includes negative torques 51 in order to actively brake the rear wheel 108 in the event of a very strong loss of traction, for example.

[0030] By applying the constant braking torque 53, the total torque on the electric bicycle 100, which can be provided solely by varying the controlled actuation of the drive unit 20, is shifted such that the second torque range 57' and the torque range 56 optimal for traction control are essentially congruent. This means that traction control can be optimally implemented in an optimal manner and for a particularly broad range of applications simply by changing the control of the drive unit 20.

[0031] A second mode of operation of the method is described below with respect to the Figure 3described. By means of the second operating mode, holding the electric bicycle 100 on an incline 70 and starting the electric bicycle 100 on the incline 70 can be provided. In this case, the method detects an incline of the electric bicycle relative to a horizontal 71. Based on the detected incline and additionally based on a total weight of the electric bicycle 100, the control unit 30 determines which holding force 76 is required to keep the electric bicycle 100 stationary on the incline 70. The holding force 76 is determined such that it is equal to a downhill force 75, which is based on the incline and the total weight of the electric bicycle 100.

[0032] The holding force 76 can preferably be provided by the drive torque of the drive unit 20 alone, or alternatively by an additional braking torque of the braking system 10.

[0033] Preferably, the second operating mode is performed exclusively during manual actuation of the brake lever 19 of the braking system 10 of the electric bicycle 100. This means that while the rider has pulled the brake lever 19, the holding force 76 is generated by the correspondingly coordinated control of the braking system 10 and the drive unit 20 in order to keep the electric bicycle 100 stationary on the incline 70.

[0034] Additionally, in the second operating mode, the start of the electric bicycle 100 can be initiated by reducing the braking torque generated by the braking system 10 in response to pedaling by the rider of the electric bicycle 101, such that the electric bicycle 100 is accelerated by the drive torque of the drive unit 20. In particular, a propulsive force is generated in the direction of the holding force 76, which is greater than the downhill force 75, in order to accelerate the electric bicycle 100.

[0035] Preferably, in both operating modes, a pitch angle of the electric bicycle 100 can additionally be detected. By monitoring the pitch angle 100, the coordinated control of braking torque and drive torque can be adjusted such that undesirable driving conditions with a high pitch angle, so-called "wheelies," can be avoided or their effects can be reduced. For this purpose, a braking torque, in particular at the rear wheel 108, can be increased and / or the drive torque of the drive unit 20 can be reduced, particularly in response to detection of a pitch angle that exceeds a predetermined pitch angle limit, or alternatively or additionally in response to detection of a predetermined minimum pitch angle change.

Claims

1. Method for operating an electric bicycle (100) which comprises a brake system (10) and a controllably actuable drive unit (20), wherein the brake system (10) has a controllably actuable actuator (5), for controlled generation of a braking torque, comprising the steps of: - controlled generation of a braking torque by means of the brake system (10), and - controlled generation of a drive torque by means of the drive unit (20), characterized in that the controlled generation of the braking torque and the controlled generation of the drive torque are performed at the same time and depending on each other in such a way as to decelerate the electric bicycle (100) with a predetermined overall braking torque or to accelerate the electric bicycle with a predetermined overall drive torque.

2. Method according to Claim 1, wherein, in a first operating mode, a predetermined constant braking torque is generated by means of the brake system (10).

3. Method according to Claim 2, wherein the predetermined constant braking torque corresponds to at least 10%, preferably at most 80%, preferably at least 30%, particularly preferably at most 60%, of a maximum drive torque that can be generated at most by means of the drive unit (20).

4. Method according to either of Claims 2 and 3, wherein the generation of the predetermined constant braking torque is performed independently of a brake lever force on a brake lever (19) of the electric bicycle (100).

5. Method according to any of Claims 2 to 4, further comprising the step of: - detection of a wheel slip, wherein the controlled generation of the drive torque is carried out depending on the detected wheel slip, in particular wherein the drive torque is reduced when the detected wheel slip exceeds a predetermined wheel slip limit value.

6. Method according to any of Claims 2 to 5, further comprising the step of: - detection of a pitch angle of the electric bicycle (100), wherein the controlled generation of the drive torque is carried out depending on the detected pitch angle, in particular wherein the drive torque is reduced when the detected pitch angle exceeds a predetermined pitch angle limit value.

7. Method according to any of the preceding claims, wherein, in a second operating mode, the controlled generation of the braking torque and the controlled generation of the drive torque is performed in such a way as to keep the electric bicycle (100) at a standstill.

8. Method according to Claim 7, further comprising the step of: - detection of an inclination of the electric bicycle (100), wherein the controlled generation of the braking torque and the controlled generation of the drive torque are carried out depending on the detected inclination.

9. Method according to Claim 8, wherein the controlled generation of the braking torque and the controlled generation of the drive torque are additionally carried out depending on a total weight of the electric bicycle (100).

10. Method according to any of Claims 7 to 9, further comprising the step of: - controlled reduction of a brake pressure generated by means of the brake system (10) in response to pedal actuation in such a way that the electric bicycle (100) is accelerated by the drive torque.

11. Method according to any of Claims 7 to 10, further comprising the step of: - detection of a pitch angle of the electric bicycle (100), wherein the controlled generation of the braking torque and / or the controlled generation of the drive torque are / is carried out depending on the detected pitch angle, in particular wherein the drive torque is reduced and / or the braking torque is increased when the detected pitch angle exceeds a predetermined pitch angle limit value.

12. Electric bicycle, comprising: - a brake system (10), - a drive unit (20), and - a control unit (30) which is designed to carry out a method according to any of the preceding claims.