Method of operating a drive device and corresponding drive device

Abstract

In a method of operating a drive device, a sound signal is generated as a function of at least one operational and/or state variable. An electric machine of the drive device is hereby as a sound generator to output the sound signal. The sound signal can be determined from a time gradient of the operational and/or state variable.

Claims

1. A method of operating a drive device, comprising: using said drive device for powering a battery electric vehicle by providing and distributing a torque to axles of the vehicle; generating a sound signal as a function of at least one operational and/or state variable; using an electric machine of the drive device as a sound generator to output the sound signal starting from a normal operating frequency of at least 10 kHz, and determining an input signal of the electric machine in response to the sound signal, wherein the input signal is generated from a superimposition of a sinusoidal, trapezoidal or a block signal with a square wave signal, with a proportion of the square wave signal increasing as a level of the sound signal increases and the operating frequency decreasing to a predetermined constant value.

2. The method of claim 1, wherein the sound signal is determined from a time gradient of the operational and/or state variable.

3. The method of claim 1, wherein the operational and/or state variable is a variable selected from the group consisting of a control pedal value, a rotation speed of the electric machine, a torque generated by the electric machine, a travel mode setting, and a speed of a motor vehicle.

4. The method of claim 1, wherein the input signal is determined as a function of a predefined rotation speed and/or predefined torque.

5. The method of claim 1, further comprising selecting a drive frequency of the input signal at a level which increases as a level of the sound signal increases.

6. A drive device for powering a battery electric vehicle by providing and distributing a torque to axles of the vehicle, comprising at least one electric machine configured to operate as a sound generator to output a sound signal starting from a normal operating frequency of at least 10 kHz generated as a function of at least one operational and/or state variable, and to determine an input signal of the electric machine in response to the sound signal, wherein the input signal is generated from a superimposition of a sinusoidal, trapezoidal or a block signal with a square wave signal, with a proportion of the square wave signal increasing as a level of the sound signal increases and the operating frequency decreasing to a predetermined constant value.

7. The drive device of claim 6, wherein the sound signal is determined from a time gradient of the operational and/or state variable.

8. The drive device of claim 6, wherein the operational and/or state variable is a variable selected from the group consisting of a control pedal value, a rotation speed of the electric machine, a torque generated by the electric machine, a travel mode setting, and a speed of a motor vehicle.

9. The drive device of claim 6, wherein the input signal is determined as a function of a predefined rotation speed and/or predefined torque.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Other features and advantages of the present invention will be more readily apparent upon reading the following description of currently preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which the sole FIG. 1 is a schematic representation of a drive device, having embodied therein the subject matter of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(2) The depicted embodiment is to be understood as illustrative of the invention and not as limiting in any way. It should also be understood that the FIGURE is not necessarily to scale and that the embodiment may be illustrated by graphic symbols, phantom lines, diagrammatic representation and fragmentary view. In certain instances, details which are not necessary for an understanding of the present invention or which render other details difficult to perceive may have been omitted.

(3) Turning now to FIG. 1, there is shown a schematic representation of a drive device, generally designated by reference numeral 1 and having embodied therein the subject matter of the present invention. The drive device 1 may find application in a motor vehicle and is shown here in the form of a hybrid drive device which includes at least two drive units, i.e. a first drive unit 2 and a second drive unit 3. The first drive unit 2 may involve an internal combustion engine and the second drive unit 3 may involve an electric machine.

(4) Both drive units 2, 3 can be operatively connected via a shaft 4 in a rigid and/or permanent manner. A separating clutch may, however, also be arranged in the shaft 4 to cut the operative connection between the drive units 2, 3. The second drive unit 3 or the electric machine is activated by a power electronics which in turn is operated by a control unit (not shown).

(5) FIG. 1 shows in addition to the drive device 1 further components of a drive train 6 of a motor vehicle. The drive train 6 includes besides the drive device 1 a starting clutch 7 and a transmission 8 which is operatively connected or at least can be operatively connected via the starting clutch 7 with the drive device 1. The drive train 6 further includes an axle 9 to which two wheels 10 are associated. The axle 9 and the wheels 10 are advantageously operatively connected, especially rigidly and/or permanently, via an axle differential 11 with the manual transmission. Thus, the axle 9 and the wheels 10 can be powered by the drive device 1.

(6) Provision is now being made to generate during operation of the drive device 1 a sound signal as a function of at least one operational and/or state variable of the motor vehicle, in particular of the drive device 1. This sound signal is outputted by a sound generator. In the non-limiting example, shown here, the function of the sound generator is assumed by the second drive unit 3, i.e. the electric machine, to generate sound emissions of the drive device 1 to inform a driver of the motor vehicle and/or further persons, for example in vicinity of the motor vehicle, about the operating state of the drive device 1. There is no need for the provision of an external sound generator.

(7) While the invention has been illustrated and described in connection with currently preferred embodiments shown and described in detail, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit and scope of the present invention. The embodiments were chosen and described in order to explain the principles of the invention and practical application to thereby enable a person skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.