Method for controlling a drive unit, control device, drive unit and vehicle

Abstract

A method is provided for controlling a drive unit for a vehicle. The drive unit comprises an electric drive, an energy storage device, and a mechanical drive operated by muscle power. The electric drive can be powered by energy from the energy storage device and provides partial drive power to assist the mechanical drive. The method includes: determining (I) an intended distance; determining (II) an average power consumption of the drive unit; determining (III) the stored energy of the energy storage device; calculating (IV) an achievable partial drive power of the electric drive, at least based on the stored energy of the energy storage device and the average power consumption of the electric drive; selecting (V) a level of assistance according to the calculation of the achievable partial drive power; and operating (VI) the electric drive with the selected level of assistance.

Description

[0001] The present invention relates to a method for controlling a drive unit, a control device for carrying out a method, a drive unit with a control device and a vehicle with a drive unit that can be temporarily operated using muscle power.

[0002] Methods for controlling the drive power of an e-bike drive unit are known. The drive unit can comprise an electric drive and a mechanical crank drive. For example, a user can choose between different support levels such as "Off," "Speed," etc. Based on the support level selected, the electric drive supports the mechanical crank drive with a partial drive power that is in a constant ratio to the partial drive power of the mechanical crank drive.

[0003] WO 2020 / 121074 A1 relates to a method for dynamically controlling the range of an electrically assisted bicycle. This method calculates a route for an electrically assisted bicycle, divides the route into segments, and calculates the amount of energy required for each segment to maximize energy efficiency. If the amount of energy consumed in the first segment deviates from the calculated amount, the amount of energy and the assistance factor are recalculated for the next segment.

[0004] DE 10 2019 107 167 A1 concerns an e-bike equipped with an electric motor that assists the rider with electric assistance. The e-bike's control system adjusts the assistance torque based on various input signals such as battery charge level, gradient, and desired assistance target to optimize the riding experience.

[0005] DE 10 2022 200 183 A1 relates to a device for predictively controlling the supply energy and range of a bicycle with an electric motor and energy source. This device comprises input devices for entering the travel distance and desired effort, determination devices for determining the route parameters and feasibility of the route, and a control device for adjusting the assist power of the electric motor based on the desired effort and the capacity of the energy source.

[0006] WO 2017 / 085579 A1 relates to a method for managing the energy ranges of a rechargeable battery pack of an assisted e-bike comprising an electric motor that delivers torque according to a pedal assistance factor. The method includes selecting a route, obtaining elevation data of the route, calculating the maximum discharge percentage of the battery pack based on the elevation profile and the assistance factor, and checking whether the battery pack has a remaining charge at the end of the route.

[0007] DE 10 2017 213 220 A1 relates to a method for operating an electric auxiliary drive of an e-bike, wherein a remaining range and / or an energy content of an energy storage device of the vehicle is determined and a support factor and / or a recuperation factor for the electric auxiliary drive of the e-bike is adapted to the determined remaining range and / or the energy content.

[0008] It is an object of the present invention to provide an improved method for controlling a drive unit based on the prior art.

[0009] The object is achieved by a method having the features of claim 1. Furthermore, the object is achieved by a control device having the features according to claim 6, by a drive unit having the features according to claim 7 and by a vehicle having the features according to claim 8. Advantageous further developments are the subject of the dependent claims.

[0010] A method for controlling a drive unit for a vehicle is provided. The vehicle is provided as a vehicle that can be operated at least temporarily using muscle power. The vehicle can be provided as an e-bike or S-Pedelec. The drive unit has an electric drive, an energy storage device, and a mechanical drive that can be operated using muscle power. The electric drive is provided as an electric motor. The energy storage device can be provided as a rechargeable battery or as a hydrogen storage device with a fuel cell. The mechanical drive is provided by a pedal crank unit. The electric drive can be operated using energy from the energy storage device. The electric drive supports the mechanical drive with partial drive power.

[0011] The electric drive and the mechanical drive can be mechanically connected, for example, via a summing gear. The total drive power of the drive unit is calculated from the sum of the partial drive power of the electric drive and the partial drive power of the mechanical drive.

[0012] If two elements are mechanically operatively connected, they are directly or indirectly coupled to one another in such a way that a movement of one element causes a reaction in the other. For example, a mechanical operative connection can be provided by a positive or frictional connection. The mechanical operative connection can correspond to the meshing of corresponding gears of the two elements. Additional elements, such as one or more spur gear stages, can be provided between the elements.

[0013] The method comprises determining an intended route. The intended route is the distance that a user, for example a cyclist, intends to travel with the vehicle. The intended route can be entered by the user as a distance. Alternatively, the user can enter a destination. The user can enter a starting point. The intended route between the starting point and the destination is then calculated. The starting point can be determined using a location determination unit, for example a GPS module. The user can enter inputs using an input unit, for example a touchpad. The method can start with the entry of a distance. Alternatively, the method can start with the entry of a destination. Alternatively, the method can start with confirmation by the user after entering various information.The method can provide the user with a route from the starting point to the destination.

[0014] The method further comprises determining an average consumption of the drive unit. The average consumption may be the mean value of the consumption over an intended route. The average consumption may be an average of the consumption over an intended route.

[0015] The method further comprises determining the stored energy of the energy storage device. The stored energy can be the charge state of a battery. The stored energy can be determined, for example, via a voltage measurement or an ampere-hour balance of a battery.

[0016] The method further comprises calculating an achievable partial drive power of the electric drive. The calculation of the achievable partial drive power is based at least on the stored energy of the energy storage device and the average consumption of the electric drive. The achievable partial drive power can be determined using a quotient of stored energy and the distance of the intended route.

[0017] The method further includes selecting a level of assistance based on the calculation of the achievable partial drive power. The level of assistance can be provided by a selected partial drive power of the electric drive.

[0018] The selected partial drive power of the electric drive can be lower than the achievable partial drive power. This can provide a safety reserve of stored energy. Multiple levels of assistance can be provided. For example, the assistance levels “Off”, “Eco” and “Comfort” can be provided. For the “Off” assistance level, the electric drive can be switched off. For the “Eco” assistance level, the partial drive power of the electric drive can be set low. For the “Comfort” assistance level, the partial drive power of the electric drive can be set to the achievable partial drive power. For example, five levels of assistance can be provided in equal steps, e.g. 20%, 40%, 60%, 80% or 100% of the achievable partial drive power of the electric drive.A continuous adjustment of the level of support can be provided.

[0019] A support level curve can be provided over the intended route. The support level curve can have multiple different support levels for individual sections of the intended route. A mathematical integral of the partial drive power corresponding to the support level or the support level curve over the distance of the intended route can be used to check whether the selected support level or support level curve can be provided by the stored energy. Losses due to energy conversion can be taken into account when selecting a support level or support level curve.

[0020] The electric drive can support the mechanical drive via a constant, partially constant, or variable torque, or a constant, partially constant, or variable power. The partial drive power of the electric drive can be independent of the partial drive power of the mechanical drive.

[0021] The method further comprises operating the electric drive with the selected level of assistance.

[0022] Determining the average consumption involves retrieving a predetermined average consumption of the drive device. The predetermined average consumption can be retrieved online from a database. The database can be provided in a data storage device of the control device. The predetermined average consumption can be determined based on calculations, test bench and driving tests, or fleet consumption. The predetermined average consumption can be determined based on the previous driving behavior of the driver of the respective vehicle.

[0023] In one embodiment, determining the average consumption can include calculating the average consumption of the drive device based on route characteristics. When calculating the average consumption, a gradient of a road can be taken into account. A positive and negative gradient can be taken into account. A degree of recuperation, for example for braking, can be taken into account when calculating the average consumption. A road surface can be taken into account when calculating the average consumption. For example, a lower average consumption can be provided for asphalt than for gravel. For example, a charging station located on a route between the starting point and the destination can be taken into account when calculating the average consumption. The average consumption can be reduced accordingly, or the stored energy can be increased accordingly.

[0024] In one embodiment, determining the average consumption can include calculating the average consumption of the drive device based on environmental influences. When calculating the average consumption, a wind direction can be taken into account. When calculating the average consumption, a wind strength can be taken into account. For example, a higher average consumption can be determined for a route with a headwind than for a route or a route section with a tailwind. When calculating the average consumption, an ambient temperature can be taken into account. For example, a higher average consumption can be determined for a low ambient temperature than for a higher ambient temperature. The method can provide the user with alternative routes from the starting point to the destination. Alternative environmental influences can be taken into account in the alternative routes.

[0025] In one embodiment, the level of assistance can be selected taking user inputs into account. When selecting a level of assistance, the user's performance level can be taken into account. For example, a lower level of assistance can be selected for a higher performance level. When selecting a level of assistance, a user's training goal can be taken into account. For example, the level of assistance can be selected such that the partial drive power of the mechanical drive to be provided by the user does not exceed or fall below a value specified by the user, or does not leave a value range specified by the user. This allows the level of assistance to be individually adapted to the user. The user inputs can be retrieved from a user account stored online. The user inputs can be entered via an input unit.The user can be warned visually or acoustically or visually and acoustically when the stored energy is not sufficient for a certain distance and a selected level of assistance.

[0026] In one embodiment, the method may further include checking whether predetermined conditions for the selected assistance level are met and, if necessary, adapting the assistance level to conditions that deviate from the predetermined conditions. After a predetermined time, the method can be automatically repeated during a driving movement, comprising the steps of determining the intended route, determining the average consumption of the drive unit, determining the stored energy of the energy storage device, calculating the achievable partial drive power of the electric drive, selecting the assistance level, and operating the electric drive. The assistance level can be adapted to new, changed conditions.The user can be warned visually, acoustically or both visually and acoustically if the destination can no longer be reached with the previously selected level of assistance from the electric drive.

[0027] In one aspect, a control device is configured to carry out a method according to one of the preceding embodiments. The control device has at least one input interface for inputting information into the control device and an output interface for controlling a drive unit. The input interface may comprise an input unit. The input unit may be configured such that a user can enter a travel destination into the control device. For example, the input unit may be provided by a bicycle computer or a touchpad. The control device may have a computing unit. The computing unit may be configured such that it can carry out a method according to one of the preceding embodiments. The control device may have a data memory. The control device may have a location determination unit, for example a GPS module.The control device can have a data transmission unit, for example a Bluetooth, Wi-Fi or mobile network module.

[0028] In one aspect, a drive unit comprises an electric drive, an energy storage device, a mechanical drive, and a control device according to one of the preceding aspects and embodiments. The electric drive can be driven with energy from the energy storage device. A partial drive power with which the electric drive supports the mechanical drive can be adjusted via the control device. The electric drive can be provided by an electric motor. The energy storage device can be provided by a rechargeable battery or a hydrogen storage device with a fuel cell. The mechanical drive can be provided by a pedal crank unit. The electric drive and the mechanical drive can be mechanically operatively connected, for example, via a summing gear.

[0029] In one aspect, a vehicle comprises at least one drive wheel and a drive unit according to one of the preceding aspects and embodiments. The vehicle can be temporarily operated using muscle power. The vehicle can be provided by an e-bike or an S-Pedelec. The drive wheel is mechanically operatively connected to the drive unit such that the drive unit can propel the vehicle. The vehicle can comprise other conventional devices such as a braking device or a steering device. Fig. 1 shows a flowchart of an embodiment of a method for controlling a drive unit.

[0030] Fig.1 shows a flowchart of an embodiment of a method for controlling a drive unit. The drive unit has an electric drive, an energy storage device, in this case a battery, and a mechanical drive, in this case a pedal crank unit, and a control device. The control device is configured to control the drive unit. The control device has a computing unit, in this case a bicycle computer, and an input unit. A user can enter information into the control device via the input unit. The control device further has a GPS module, a navigation system, a data transmission unit, and a data memory.

[0031] The drive unit is used in a vehicle that can be partially powered by human power, in this case an e-bike. In addition to the drive unit, the vehicle has other standard features such as a braking system, a steering system, and two wheels, one of which is a drive wheel.

[0032] The electric drive and the mechanical drive are mechanically connected to each other via a summing gear so that they jointly provide a total drive power with which the drive wheel is driven. The electric drive can be operated using energy from the energy storage device. The electric drive provides partial drive power with which the electric drive supports the mechanical drive. The level of assistance with which the electric drive supports the mechanical drive is set using the following procedure.

[0033] In a first step I, the control unit determines an intended route. A user can enter either a distance or a destination into the bike computer. Once a destination is entered, the bike computer determines the starting position and calculates the intended route based on the starting position, the destination, and geographical, topographical, and other route data stored in the bike computer.

[0034] In a further step II, the control unit determines the average consumption of the drive unit. To do this, the control unit evaluates route characteristics, such as uphill and downhill gradients, road surface conditions, and curves. Furthermore, the control unit evaluates environmental influences, such as wind (headwind and tailwind), rain, and temperature. Based on this evaluation, the control unit retrieves a test bench consumption for the respective road surface characteristics and environmental influences from an online database via the data transmission unit.

[0035] In a further step III, the stored energy of the energy storage device is determined by a voltage measurement.

[0036] In a further step IV, an achievable partial drive power of the electric drive is calculated based on the stored energy of the energy storage device and the average consumption of the electric drive.

[0037] In a further step V, a level of assistance is selected based on the calculation of the achievable partial drive power. A user input is taken into account. A user input is a minimum power level that the user is willing to provide. The minimum power is provided by the user via the mechanical drive. A user input could also be, for example, a "Comfort" drive program, in which the level of assistance from the electric drive is as high as possible with the stored energy and the distance of the intended route. A user input could also be, for example, an "Off" drive program, in which the electric drive is switched off.

[0038] In a further step VI, the electric drive is operated with the selected level of support.

[0039] After a predetermined time, a further step VII checks whether the predetermined conditions for the selected assistance level are still met. To do this, steps I through VI are performed again. If the conditions have changed and deviate from the predetermined conditions, the assistance level is adjusted to the new, changed conditions, such as a change in stored energy, changed environmental influences, a changed distance, or a changed intended route. Reference symbol I Determining an intended route II Determining an average consumption of the drive unit III Determining the stored energy of the energy storage device IV Calculating an achievable partial drive power of the electric drive V Selecting a level of support VI Operating the electric drive VII Checking and adjusting the level of support

Claims

[1] Method for controlling a drive unit for a vehicle with an electric drive, an energy storage device and a mechanical drive operable by muscle power, wherein the electric drive can be operated with energy from the energy storage device to support the mechanical drive with partial drive power, the procedure includes: Determining (I) an intended route, Determining (II) an average consumption of the drive unit, Determining (III) the stored energy of the energy storage device, Calculating (IV) an achievable partial drive power of the electric drive, at least based on the stored energy of the energy storage device and the average consumption of the electric drive, Selecting (V) a level of assistance according to the calculation of the achievable partial drive power, and Operating (VI) the electric drive with the selected level of support, characterized by that determining (II) the average consumption comprises retrieving a predetermined average consumption of the drive device, wherein the predetermined average consumption is calculated from test bench and driving tests, wherein the predetermined average consumption is retrieved from a database. [2] Method according to claim 1, characterized by that determining (II) the average consumption additionally comprises calculating the average consumption of the drive device based on route characteristics. [3] Method according to one of the preceding claims, characterized by that determining (II) the average consumption additionally comprises calculating the average consumption of the drive device based on environmental influences. [4] Method according to one of the preceding claims, characterized bythat the selection (V) of a level of support takes into account user inputs. [5] Method according to one of the preceding claims, characterized by that the procedure further comprises: Checking (VII) whether predetermined conditions for the selected level of assistance are met and, if necessary, adapting the level of assistance to conditions deviating from the predetermined conditions. [6] Control device configured to carry out a method according to any one of the preceding claims, wherein the control device comprises at least one input interface for inputting information into the control device and an output interface for controlling a drive unit. [7] Drive unit with an electric drive, an energy storage device, a mechanical drive operable by muscle power and a control device according to claim 6, wherein the electric drive can be driven with energy from the energy storage device and a partial drive power with which the electric drive supports the mechanical drive can be set via the control device. [8] Vehicle with at least one drive wheel and a drive unit according to claim 7, wherein the vehicle can be temporarily operated by muscle power, the drive wheel being mechanically connected to the drive unit in such a way that the drive unit can move the vehicle.

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