System and method for diagnosing a park function for an in-wheel electric motor

1 . A method for diagnosing a park function in a vehicle including a plurality of in-wheel motors each including first and second planetary gear sets, the method comprising, at a computing device:

selectively engaging both of the first and second planetary gear sets in each of the plurality of in-wheel motors to place each of the in-wheel motors into a park state;

engaging respective locking mechanisms of each of the in-wheel motors to lock each of the respective first and second gear sets in the engaged condition;

upon ignition of the vehicle, determining whether a corresponding one of the in-wheel motors maintains the park state by performing a motor rocking function on the corresponding in-wheel motor to move the engaged first and second planetary gear sets forward and backward with a predefined force and determine whether the resultant forward and backward movement of the engaged first and second planetary gear sets is less than or greater than a predetermined threshold; and

operating the vehicle in a selected one of a plurality of operating modes based on the determination of whether the corresponding one of the in-wheel motors maintained the park state.

2 . The method of claim 1 , further comprising:

operating the vehicle in a first operating mode in response to a determination that during the motor rocking function each of first and second planetary gear sets of the in-wheel motors had movement being less than the predetermined threshold and thus maintained the park state;

operating the vehicle in a second operating mode in response to a determination that during the motor rocking function at least one set of first and second planetary gear sets but not all of the sets of first and second planetary gear sets of the in-wheel motors had movement being less than the predetermined threshold and thus at least one in-wheel motor maintained the park state; and

operating the vehicle in a third operating mode in response to a determination that during the motor rocking function all of the first and second planetary gears sets of the in-wheel motors had movement being greater than the predetermined threshold and thus none of the in-wheel motors maintained the park state.

3 . The method of claim 1 , wherein determining whether the corresponding one of the in-wheel motors maintains the park state includes de-energizing at least one solenoid configured to, when energized, cause the first and second planetary gear sets to engage a clutch assembly.

4 . The method of claim 3 , wherein determining whether the corresponding one of the in-wheel motors maintains the park state includes de-energizing two solenoids respectively configured to, when energized, cause the first and second planetary gear sets to engage the clutch assembly.

5 . The method of claim 4 , wherein the first and second planetary gear sets correspond to first and second drive gears, respectively.

6 . The method of claim 1 , wherein the vehicle includes two of the in-wheel motors.

7 . The method of claim 1 , wherein the vehicle includes four in-wheel motors.

8 . The method of claim 1 , wherein the respective locking mechanisms each include a pin configured to selectively engage with a shift fork to prevent movement of the shift fork.

9 . The method of claim 1 , wherein the respective locking mechanisms include a single pin configured to selectively engage with one or more shift forks to prevent movement of the one or more shift forks.

10 . A computing device configured to execute instructions stored in memory that, when executed, cause the computing device to carry out steps for diagnosing a park function in a vehicle including a plurality of in-wheel motors each including first and second planetary gear sets, the steps including:

selectively engaging both of the first and second planetary gear sets in each of the plurality of in-wheel motors to place each of the in-wheel motors into a park state;

engaging respective locking mechanisms of each of the in-wheel motors to lock each of the respective first and second gear sets in the engaged condition;

upon ignition of the vehicle, determining whether a corresponding one of the in-wheel motors maintains the park state by performing a motor rocking function on the corresponding in-wheel motor to move the engaged first and second planetary gear sets forward and backward with a predefined force and determine whether the resultant forward and backward movement of the engaged first and second planetary gear sets is less than or greater than a predetermined threshold; and

operating the vehicle in a selected one of a plurality of operating modes based on the determination of whether the corresponding one of the in-wheel motors maintained the park state.

11 . The computing device of claim 10 , the steps further comprising:

operating the vehicle in a first operating mode in response to a determination that during the motor rocking function each of the first and second planetary gears sets of the in-wheel motors had movement being less than the predetermined threshold and thus maintained the park state;

operating the vehicle in a second operating mode in response to a determination that during the motor rocking function at least one set of first and second planetary gear sets but not all of the sets of first and second planetary gear sets of the in-wheel motors had movement being less than the predetermined threshold and thus at least one in-wheel motor maintained the park state; and

operating the vehicle in a third operating mode in response to a determination that during the motor rocking function all of the first and second planetary gear sets of the in-wheel motors had movement being greater than the predetermined threshold and thus none of the in-wheel motors maintained the park state.

12 . The computing device of claim 10 , wherein determining whether the corresponding one of the in-wheel motors maintains the park state includes de-energizing at least one engagement mechanism configured to, when energized, cause the first and second planetary gear sets to engage a clutch assembly.

13 . The computing device of claim 12 , wherein determining whether the corresponding one of the in-wheel motors maintains the park state includes de-energizing two engagement mechanisms respectively configured to, when energized, cause the first and second planetary gear sets to engage the clutch assembly.

14 . The computing device of claim 13 , wherein the first and second planetary gear sets correspond to first and second drive gears, respectively.

15 . The computing device of claim 10 , wherein the vehicle includes two of the in-wheel motors.

16 . The computing device of claim 10 , wherein the vehicle includes four in-wheel motors.

17 . The computing device of claim 10 , wherein the respective locking mechanisms each include a pin configured to selectively engage with a shift fork to prevent movement of the shift fork.

18 . The computing device of claim 10 , the steps further comprising using data from sensors and historical vehicle operating data to update calibration data located in memory to dynamically adjust thresholds for determining whether the first and second planetary gear sets are engaged or disengaged over a lifetime of the vehicle.

19 . The computing device of claim 18 , the steps further comprising using the updated calibration data for vehicle propulsion operations and for confirming an operational status of the park state.