Method for operating a drive system of a bicycle that is at least temporarily electrically powered

Abstract

The present invention relates to a method (100) for operating a drive system (200) comprising a plurality of components (202, 204, 205) of a bicycle (300) that is at least temporarily electrically powered, comprising the steps: - providing (S1) at least one request of a first component (202) and one request of a second component (204) from the plurality of components of the drive system (200), - comparing (S2) the request of the first component (202) with the request of the second component (204) with regard to a thermal load situation of the first component (202) and the second component (204), - adjusting (S3) an operating behavior of the first component (202) and / or the second component (204) on the basis of the comparison.

Description

Prior ArtThe present invention relates to a method for operating a drive system of an at least temporarily electrically driven bicycle and to a drive system for an at least temporarily electrically driven bicycle and to a bicycle.At present, there are a large number of different solutions for improving the driving dynamics of electrically driven bicycles or e-bikes. As the variety of drive concepts for electrically driven bicycles increases, the need for robust and innovative control methods is continually increasing.Disclosure of the InventionThe method according to the invention for operating a drive system, comprising a plurality of components, of an at least temporarily electrically driven bicycle having the features of claim 1 has the advantage over the known art that thermal overloading of individual components can be avoided with the aid of the system-based or macroscopic monitoring of an electric bicycle drive system without significantly influencing the driving behavior or the driving dynamics of the electrically driven bicycle. In this case, the driving behavior or the driving dynamics can be influenced in particular in such a way that it is hardly noticeable to a rider of a bicycle. It is further preferably possible to create a reproducible customer experience with the method, independently of external influences and design features of the electric drive system of the bicycle, in that the operating behavior of the components of the drive system is matched to one another in a thermal load situation. The drive system can regulate itself independently and without user input in such a way that no limitation of one of the components occurs. The driving dynamics for the user remain as unchanged as possible, regardless of the thermal load situation of the individual components. A further advantage is that a possible power reduction for component protection can be flexibly adapted, which can be adapted in such a way that there is as little influence as possible on the driving dynamics of the electrically driven bicycle.This is achieved according to the invention in that the method for operating a drive system, comprising a plurality of components, of an at least temporarily electrically driven bicycle has the steps:providing at least one request for a first component and a request for a second component from the plurality of components of the drive system,comparing the requirement of the first component with the requirement of the second component with respect to a thermal load situation of the first component and of the second component,adjusting an operating behavior of the first component and / or of the second component on the basis of the comparison.In other words, the operating behavior of at least one component can be adapted by means of the method as a result of a comparison of the plurality of components of the drive system. The adaptation of the operating behavior is effected in particular in such a way that a power output of a component of the plurality of components is at least temporarily reduced. The adaptation of the operating behavior can be a reduction of a power output of a battery unit, a reduction of the power consumption of an electric drive unit, a reduction of the torque of the electric drive unit and / or the like. Furthermore, at least one property of a component from the plurality of components can be detected with the method. In this case, for example, a property such as a temperature value can be detected. On the basis of the comparison between the requirements of the two components, the operating behavior of the components can be adapted.For example, there is a request in the form of an increase in power output, such as a speed increase or a torque increase of a user of the electrically driven bicycle. The drive system determines, for example, how long such an increased power output can be provided taking into account the thermal load situation of the individual components. The operating behavior of one or more components can then be adjusted in a targeted manner in order to provide a reproducible and comfortable driving experience independently of a thermal load situation of an individual component or a plurality of components. In particular, on the basis of the comparison of the requirements of the components, the operating behavior of the components can be adapted to one another in a coordinated manner.The drive system includes a plurality of components. The first component is in particular a drive unit, the second component is in particular a battery unit. A further component of the drive system is any component of a bicycle which has mechanical, electrical and / or electronic components and outputs a mechanical and / or electrical power during operation of the drive system. A power output of a component is to be understood in the broad sense as any output or output of a physical variable which the respective component provides and which represents its performance. An indication of a physical variable per unit time can also represent the power output of a component. A power output of the battery unit may be expressed by, for example, an electric power or a discharge current. A power output of a drive unit may be expressed by a torque or a mechanical power, for example. A power output of a component may also be an output signal output by the component and used to control one or more other components. Examples of further components are: a user interface unit, which is designed for the display and / or control of the drive system by the user of the bicycle; a gear shifting device, a seat post device, a damping device, which are each equipped with an actuator. The components of the drive system are connected to one another wirelessly or by wire. For example, the battery unit can thus provide a voltage supply for the components, in particular for the drive unit.The drive system furthermore comprises a control unit which is designed to control the drive system. The control unit can be designed, for example, as an independent component which is connected wirelessly or by wire to the plurality of components of the drive system. The control unit can also be integrated into one of the components of the drive system, for example. For example, the control unit can be integrated into the battery unit or into the drive unit. The control unit can also be designed, for example, as a distributed system distributed over a plurality of components.The dependent claims show preferred developments of the invention.The method further preferably comprises the step of: adapting the requests on the basis of a user indication.An advantage of this embodiment is that the request for the first and / or the second component can be adapted by means of the user input in order to be able to correspond to a driving request of the driver of the drive system of the electric bicycle, such as, for example, a speed listening or torque increase on the drive system. For example, on the basis of the user input, which is indicative of a torque or speed increase, the request of the first and / or of the second component can be adapted or updated accordingly. This can result in a new comparison between the adapted requirements of the components with regard to their thermal load situation. With the renewed comparison, a renewed adaptation of the operating behavior may possibly be necessary if the adapted requirements are selected such that the thermal load situation cannot reflect them. Thus, for example, in the event of an increased torque demand, the power output in the form of the torque can be reduced by a predetermined amount or dynamically in order to be able to provide the driver with a pleasant driving feel despite a thermal load situation.In addition, the method preferably comprises the step of: providing a property of the first component and / or of the second component. A property can be considered in particular to be a temperature variable which describes the thermal state of the component. A temperature variable can be, for example, a temperature or a temperature gradient.In the method, the adaptation of the operating behavior is preferably configured to reduce a power output of the first component and / or of the second component. The reduction of the power output is effected in particular by gradual, for example stepwise or continuous, reduction of the power output, in particular in order to avoid abrupt stopping of the power output from a comparatively high power output as far as possible. Gradually reducing the power output also has the advantage that power can be output over a longer period of time.An advantage of the method is that the operating behavior of the drive system can be dynamically adjusted by means of the control loop between property (for example temperature variable), requirement (for example power output) and the adaptation of the operating behavior, taking into account the thermal load situation of the components of the drive system. Thus, the driving dynamics of the electrically driven bicycle can be realized without great changes or fluctuations.In one configuration of the method, the provision of the request for the first component and / or the request for the second component comprises a provision of a power output of the first component and / or of the second component. Providing the power output may be a current power output or a future power output. A power output of a component is understood to mean an output of power of the component, wherein different physical variables can represent the power output of the respective component. A power output of a drive unit can be understood to mean, for example, a torque or a speed which can be provided by the drive unit. A power output of a battery unit can be understood to mean, for example, a discharge current or a capacity which the battery unit can provide. An actual power output of a component describes in particular a power output which can be provided at the moment by the component. Future power output particularly describes power output predicted from estimation, calculation, or the like at a later time.Providing the request for the first component and / or the request for the second component may further comprise providing a time variable which indicates when an adaptation of the operating behavior of the first component and / or of the second component due to a thermal load situation is required. The power output of the respective component is dependent on the thermal load situation of the respective component. If the thermal load situation of the respective component is comparatively high, the component can provide a corresponding power output only for a specific period of time. Thereafter, the power output must be reduced in order to avoid a thermal overload situation or a critical thermal state of the component. Taking into account the thermal load situation of the component, a time variable can be determined which indicates when an adaptation of the operating behavior of the component is required. A time variable may be a time from which a reduction in the power output is required, or a time duration within which the component can provide the current power output, or a time duration within which the component can provide a reduced power output. Such a time variable can be determined, for example, from a temperature and / or a temperature gradient of the component and a current and / or future power output of the component and optionally further parameters. The determination of the time variable can take place in particular in a control unit.Preferably, comparing the request of the first component with the request of the second component comprises comparing the time size of the first component with the time size of the second component. In order to compare the first component and the second component with respect to a thermal load situation, the time variables of the two components are compared with one another, which time variables indicate when an adaptation of the operating behavior of the component is required. The comparison of the two time variables can take place in particular in a control unit.In particular, the comparison comprises a determination of a critical component, wherein the critical component is considered to be that of the two components whose time variable is smaller than the time variable of the other component. That of the two components with the smaller time variable is more heavily thermally loaded than the other component and requires an adaptation of the operating behavior earlier than the other component. The determination of the critical component can take place in particular in a control unit.Furthermore, the comparison can preferably also comprise a determination of a reduced power output of the critical component. The reduced power output is selected in such a way that a matched operating behavior on the basis of the reduced power output leads to the time variable of the critical component being increased. This has the advantage that the operating behavior of the first and the second component is at least partially adjusted with respect to the thermal load situation: the difference between the time variable of the critical component and the other component is reduced.In the next step, the adaptation of the operating behavior of the critical component is preferably carried out on the basis of the reduced power output. Thus, the critical component can provide power output over a longer period of time, although at a lower level. The operating behavior of the two components can thus be at least partially matched to one another.An advantage of this embodiment is that in the case of a thermal load situation of the drive system, it is possible to determine which of the components should first have a power reduction. The operating behavior of that component which has the smallest period of time can thus be changed, so that the entire drive system has a comparable operating behavior, regardless of which component should first have a power reduction. In particular, the operating behavior of the drive system as a whole is modified in such a way that the driving experience does not have any noticeable changes for a user.For example, the drive system has an electric battery unit and an electric drive unit. In this case, the battery unit can provide a power output in the form of a discharge current and the drive unit can provide a torque as a power output. For example, the thermal load situation of the drive unit can be such that the operating behavior has to be adapted in five minutes. The thermal load situation of the battery unit can be, for example, such that the operating behavior of the battery unit must be adapted in three minutes. In this case, the battery unit can thus be identified as the component which has the smallest time variable, such as three minutes in this example. Further, the output or the operating behavior of the battery unit can be adjusted by reducing, so that the time period increases. The operating behavior can be adapted in such a way that the power output takes place in particular in a range which has little or no influence on the driving dynamics of the electric bicycle. In this case, the reduction in the power output can be varied in such a way that the battery unit likewise requires the adaptation of the operating behavior in five minutes, with the result that the adaptation for the battery unit and the drive unit takes place simultaneously.In one embodiment of the method, the adaptation of the operating behavior is effected by reducing the power output in such a way that a comfortable power output of the first component and / or of the second component is made possible. A comfortable power output is to be understood as a power output which can be provided by the respective component by maintaining predetermined limit values for the power output of the respective component. These predetermined limit values are defined on the system side in such a way that they enable a comfortable driving behavior even if a thermal load situation of at least one of the components occurs and an adaptation of the operating behavior on the basis of the thermal load situation is necessary. A comfortable power output is controlled by the predetermined limit values such that the adaptation of the operating behavior is substantially not recognizable to the user of the bicycle. The user of the bicycle does not notice the reduction of power output because it is gradual. In particular, a comfortable power output is a power output that prevents an abrupt reduction in the power output or a steep reduction with a high reduction in the power output per unit time or even an abrupt shutdown. The comfortable power output is also achieved by matching the operating behavior of the components to one another.In a further embodiment of the method, the following step is also provided: comparing the requirement of the first component and / or of the second component with a predetermined limit value. If it is determined during the comparison of the request that the request for the first and / or the second component, preferably the request for both components, does not exceed the predetermined limit value, the drive system is initially operated further without adapting the operating behavior or another intervention in the drive system. If, however, it is determined in the comparison of the requirements with the predetermined limit value that the first and / or the second component with its requirement exceeds the predetermined limit value, the following step is carried out next: comparing the requirement of the first component with the requirement of the second component with respect to a thermal load situation of the first component and the second component. This method step has already been explained in more detail further above. An intervention in the drive system by comparing or adjusting the thermal load situation of the components linked in the drive system accordingly takes place in particular above a predetermined limit value. Below the predetermined limit value, no unnecessary intervention takes place due to a specific thermal load situation.The predetermined limit value can be defined in particular in that the requirement of the first component and / or of the second component below the limit value enables a stable power output of the first component and / or of the second component. A stable power output of a component is in particular a power output in which no adaptation of the operating behavior of the component due to a thermal load situation is required. With stable power output of a component, the component can provide the power output without reaching a critical thermal state that would require adjusting the performance of the component. Below a limit value defined in this way, the components are in a temperature range which is not thermally critical.In this embodiment of the method, the requirements of the components in the system are compared or matched only if an adaptation of the operating behavior is imminent for at least one of the components with regard to its thermal load situation. If the requirements of both or all components are below the limit value predetermined in this way, both components are in a range of stable power output in which no adaptation of the operating behavior due to a thermal load situation is required.The limit value up to which no intervention into the drive system takes place by comparing or matching the requirements of the components can alternatively also be defined on the basis of criteria other than the criteria for a stable power output.A further aspect of the invention relates to a drive system for at least one temporarily electrically driven bicycle, which has a control unit. The control unit is configured to carry out the method according to the invention. The control unit is designed to provide at least one request for a first component and one request for a second component from a plurality of components of the drive system. The control unit is also configured to compare the requirement of the first component with the requirement of the second component of the plurality of components of the bicycle in terms of a thermal load. The control unit is furthermore designed to adapt an operating behavior of the first component and / or of the second component on the basis of the comparison.An advantage of the drive system according to the invention is that the power output, such as the torque of the component, can be reduced by means of the control unit if this is required in order to make the driving behavior of the electrically driven bicycle as constant as possible. In this case, the drive system can have a drive unit as the first component and a battery unit as the second component.A further aspect of the invention relates to an at least temporarily electrically operated bicycle which has a drive system having a plurality of components and a control unit which is configured to carry out steps of the method as described above and below.Brief Description of the DrawingsHereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings. In the drawing, the following is: FIG. 1 illustrates a logical association of portions of the method according to an embodiment, FIG. 2 shows a flow chart to illustrate steps of the method according to one embodiment, FIG. 3 shows a flow chart to illustrate steps of the method according to one embodiment, FIG. 4 shows a bicycle according to an embodiment, FIG. 5 illustrates a drive system according to an embodiment.Embodiment(s) of the InventionFIG. 1 is an illustration for understanding logic for avoiding performance reductions in operation of a bicycle according to an embodiment. Logic 400 includes a plurality of individual steps. Logic 400 includes predicting a future torque or electrical power output request from driver 402. Depending on the performance request 402 of the driver, a comparison 404 can be made between the performance request 402 and a limit value. If the limit value is not exceeded in the comparison 404 or the requirement 402 can be fulfilled, no further steps are considered 410. Should the requirement 402 not be met 406 in the comparison 404, a plurality of steps may be initiated. These steps can be in particular a calculation of a time period 414 until a power minimization can take place. Further, one of these steps may be calculating a comfortable performance minimization 412. Another step may be calculating a time to initiate performance minimization 416. Another step may be calculating the power or torque limits 418. A further step may be the outputting of the limitation or the power minimization 420. Another step may be transmitting or monitoring the boundary 426. Interface 422 may provide information for steps 404, 412, and 418. Based on the data from the interface 422, in particular a stable power output or torque can be predicted.FIG. 2 shows a flow chart to illustrate steps of method 100 according to the present invention. The method 100 comprises the step of providing S 1 at least one request for a first component 202 and one request for a second component 204 from a plurality of components 205 of the drive system 200 of the bicycle 300. Furthermore, the method 100 comprises the step of comparing S 2 the requirement of the first component 202 with the requirement of the second component 204 with respect to a thermal load situation. The method 100 further comprises the step of adjusting S 3 an operating behavior of the first component 202 and / or the second component 204 on the basis of the comparison.FIG. 3 shows a flow chart to illustrate steps of method 100, according to one embodiment. In this case, the method 100 comprises the steps S 1 to S 3, as already explained in FIG. 2. In this case, the step of providing S 1 the requirements of the first component 202 and of the second component 204 comprises, in particular, providing a current or future power output of the first and of the second component 202, 204 and also providing a time variable of the two components 202, 204 which specifies when adaptation of the operating behavior of the respective component on the basis of a thermal load situation is required. The method 100 further comprises the step of adapting S 4 the request on the basis of a user input. The method 100 further comprises the step of providing S 9 a property, for example a temperature variable, of the first and / or the second component 202, 204. In addition, the method 100 comprises the step of comparing S 5 the time variable of the first component 202 with the time variable of the second component 204 and determining S 6 a critical component. In this case, that of the two components 202, 204 is classified as a critical component whose time variable is smaller than the time variable of the other component. The critical component is therefore that of the two components 202, 204 which, owing to their thermal load situation, makes it necessary to adapt the operating behavior earlier. Furthermore, the method 100 comprises the step of determining S 7 a reduced power output of the critical component, wherein the reduced power output results in the time variable of the critical component being increased. The determined reduced power output is applied in step S 3 of adapting the operating behavior of the critical component. This makes it possible to achieve a comfortable riding feel for the user of the bicycle. In the variant shown here, the method also comprises a step S 8 of comparing the requirement of the first component 202 and the second component 204 with a predetermined limit value, which defines that the power output of the first component 202 and / or of the second component 204 below the limit value enables a stable power output of the components 202, 204. Below the limit value, the components 202, 204 are in a temperature range that is thermally non-critical for the components 202, 204. An adaptation of the operating behavior, in particular a lowering of the power output, due to a thermal load situation is not necessary in this area.FIG. 4 schematically shows an at least partially electrically operated bicycle 300 with a drive system 200 according to an embodiment. The drive system 200 is configured to perform the steps of the method 100 as described above.FIG. 5 illustrates the drive system 200 according to an embodiment. The drive system 200 comprises a plurality of components 205. A first component 202 is formed by a drive unit 206. A second component 204 is formed by a battery unit 208. A further component 205 is formed by a user interface unit 210. The drive system 200 further includes a control unit 220. In the embodiment according to FIG. 5, the control unit 220 is designed as an independent, further component 205. In the embodiment according to FIG. 5, three further components 205 are provided, which are not designated in any more detail. Examples of such further components 205 can be: a gear shifting device, a seat post device, a damping device. The control unit 220 is configured to carry out the steps of the method 100 as described above.

Claims

Method (100) for operating a drive system (200), comprising a plurality of components (202, 204, 205), of an at least temporarily electrically driven bicycle (300), comprising the steps of: - providing (S1) at least one request for a first component (202) and a request for a second component (204) from the plurality of components of the drive system (200), - comparing (S2) the request for the first component (202) with the request for the second component (204) with respect to a thermal load situation of the first component (202) and the second component (204), - adjusting (S3) an operating behavior of the first component (202) and / or the second component (204) on the basis of the comparison.The method (100) of claim 1, further comprising the step of: adjusting (S4) the request based on a user input.Method (100) according to one of the preceding claims, further comprising the step of: providing (S9) a property, in particular a temperature variable, of the first component (202) and / or of the second component (204).Method (100) according to one of the preceding claims, wherein the adaptation (S3) of the operating behavior is configured to reduce a power output of the first component (202) and / or of the second component (204).Method (100) according to one of the preceding claims, wherein the provision (S1) of the request for the first component (202) and / or of the request for the second component (204) comprises providing an, in particular current or future, power output of the first component (202) and / or of the second component (204).Method (100) according to one of the preceding claims, wherein the provision (S1) of the request for the first component (202) and / or the request for the second component (204) comprises providing a time variable which indicates when an adaptation (S3) of the operating behavior of the first component (202) and / or of the second component (204) is required on account of a thermal loading situation.The method according to any of the preceding claims, wherein comparing (S2) the request of the first component (202) with the request of the second component (204) comprises comparing (S5) the time size of the first component (202) with the time size of the second component (204).Method according to Claim 7, wherein the comparison (S2) comprises ascertaining (S6) a critical component, wherein the critical component is considered to be that of the two components (202, 204) whose time variable is smaller than the time variable of the other component.Method according to one of claims 7 to 8, wherein the comparing (S2) comprises determining (S7) a reduced power output of the critical component, wherein the reduced power output results in the time size of the critical component being increased.Method according to Claim 9, wherein the adaptation (S3) of the operating behavior of the critical component takes place on the basis of the reduced power output.Method according to one of Claims 8 to 10, wherein the adaptation (S3) of the operating behavior is configured to reduce the power output of the critical component in such a way that the time variable of the critical component is increased.Method (100) according to one of the preceding claims, wherein the adaptation (S3) of the operating behavior is effected by reducing the power output in such a way that switching off of the first component (202) and / or of the second component (204) is avoided.Method (100) according to one of the preceding claims, wherein the adaptation (S3) of the operating behavior is effected by reducing the power output in such a way that a comfortable power output of the first component (202) and / or of the second component (204) is enabled, wherein the comfortable power output is defined by compliance with predetermined limit values for the power output of the respective component (202, 204).Method (100) according to one of the preceding claims, further comprising the step of: comparing (S8) the request for the first component (202) and / or the second component (204) with a predetermined limit value, wherein the comparing (S2) the request for the first component (202) with the request for the second component (204) is carried out with respect to a thermal load situation of the first component (202) and the second component (204) if the predetermined limit value is exceeded.The method (100) of claim 14, wherein the predetermined threshold is defined by the power output of the first component (202) and / or the second component (204) below the threshold enabling stable power output of the first component (202) and / or the second component (204), the stable power output being defined by no need to adjust the performance due to a thermal load situation.Drive system (200) for an at least temporarily electrically driven bicycle (300), comprising a plurality of components (202, 204, 205) and a control unit (220) which is configured to provide at least a request for a first component (202) and a request for a second component (204), wherein the control unit (220) is configured to compare the request for the first component (202) with the request for the second component (204) with respect to a thermal load situation of the first component (202) and of the second component (204), wherein the control unit (220) is configured to adapt an operating behavior of the first component (202) and / or of the second component (204).The propulsion system (200) of claim 16, wherein the first component (202) is a propulsion unit (206) and the second component (204) is a battery unit (208).A bicycle (300) comprising a drive system (200) according to claim 16 or 17.

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