Method for switching a gear ratio of a switchable gear mechanism, control device and vehicle

1 . A method for switching a gear ratio of a switchable gear mechanism of a vehicle having an electric motor for driving the vehicle, the method comprising:

generating a motor torque with the electric motor;

determining an upcoming gear change;

initiating the gear change by reducing the generated motor torque at a beginning of a predetermined gear change timespan;

changing the gear ratio of the switchable gear mechanism during the predetermined gear change timespan after the reduction in the generated motor torque; and

generating at least one motor torque pulse with the electric motor during the predetermined gear change timespan.

2 . The method according to claim 1 , wherein the vehicle includes a pedal axle associated with cranks, the method further comprising:

sensing at least one of (i) a rotational angle position of the pedal axle, (ii) at least one position of a crank, (iii) a driver torque, (iv) and a speed of the pedal axle; and

determining a time point for the beginning of the predetermined gear change timespan depending on the sensed at least one of the rotational angle position of the pedal axle, the at least one position of the crank, the driver torque, and the speed of the pedal axle, wherein

reducing the amount of the generated motor torque depends on the determined time point, and/or changing the gear ratio of the switchable gear mechanism depends on the determined time point.

3 . The method according to claim 2 , further comprising:

displaying information to the driver at the determined time point for reducing the generated motor torque and/or at the predetermined gear change timespan for changing the gear ratio.

4 . The method according to claim 1 , wherein the generating of the at least one motor torque pulse includes generating two, three, or four motor torque pulses during the predetermined gear change timespan in order to change the gear ratio.

5 . The method according to claim 1 , wherein, during the predetermined gear change timespan, the generated motor torque pulses result in an average torque having an amount deviation of less than or equal to 50 percent of an amount of the generated motor torque immediately prior to the reduction.

6 . The method according to claim 1 , wherein, during the predetermined gear change timespan, a sum of at least two reduction timespans in which the motor torque is reduced is less than or equal to a sum of at least one pulse duration of the generated at least one motor torque pulse.

7 . The method according to claim 1 , wherein an amount of motor torque pulses generated during the predetermined gear change timespan remains the same.

8 . The method according to claim 1 , wherein an amount of motor torque pulses generated during the predetermined gear change timespan varies.

9 . The method according to claim 1 , wherein a duration of the predetermined gear change timespan and/or a number of motor torque pulses generated in the at least one motor torque pulse are adjusted depending on (i) a detected speed of the vehicle, (ii) a detected pedaling frequency of a driver, and/or (iii) a detected currently set gear ratio of the switchable gear mechanism.

10 . The method according to claim 1 , wherein the determination of the upcoming gear change includes detecting an operator input on a gear change button.

11 . The method according to claim 1 , wherein the determination of the upcoming gear change is made using a gear change detection sensor on at least one of a Bowden cable of the switchable gear mechanism and the switchable gear mechanism.

12 . The method according to claim 1 , wherein the determination of the upcoming gear change is made automatically or semi-automatically depending on a driver torque of the driver detected by a torque sensor and/or via a driver pedaling frequency detected by a speed sensor.

13 . A control device for the vehicle, wherein the control device is configured to execute the method for switching the gear ratio of the switchable gear mechanism according to claim 1 .

14 . The method according to claim 1 , wherein none of the torque generated by the electric motor during the predetermined gear change timespan is a negative torque.

15 . A vehicle comprising:

a switchable gear mechanism;

an electric motor configured to drive the vehicle; and

a control device configured to operate the vehicle to:

generate a motor torque with the electric motor;

determine an upcoming gear change;

initiate the gear change by reducing the generated motor torque at a beginning of a predetermined gear change timespan; and

change a gear ratio of the switchable gear mechanism during the predetermined gear change timespan after the reduction in the generated motor torque; and

generate at least one motor torque pulse with the electric motor during the predetermined gear change timespan.

16 . The vehicle according to claim 15 , wherein the vehicle is an electric bicycle.

17 . The vehicle according to claim 15 , wherein none of the torque generated by the electric motor during the predetermined gear change timespan is a negative torque.

18 . A method for switching a gear ratio of a switchable gear mechanism of a vehicle having an electric motor for driving the vehicle, the method comprising:

generating a motor torque with the electric motor;

determining an upcoming gear change;

initiating the gear change by reducing the generated motor torque at a beginning of a predetermined gear change timespan;

changing the gear ratio of the switchable gear mechanism during the predetermined gear change timespan after the reduction in the generated motor torque; and

generating at least one motor torque pulse with the electric motor during the predetermined gear change timespan such that an average torque during the predetermined gear change timespan is greater than the reduced generated motor torque at the beginning of the predetermined gear change timespan.

19 . The method according to claim 18 , wherein none of the torque generated by the electric motor during the predetermined gear change timespan is a negative torque.