Method and device for operating a hybrid vehicle comprising an electric energy store, an electric motor and an internal combustion engine

Abstract

A method and a device operate a hybrid vehicle having an electric energy store, an electric propulsion system and an internal combustion engine. A special operating strategy that can be initiated for the internal combustion engine allows the state of charge of the energy store to be increased when predefined acoustic conditions are met. The special operating strategy has a performance-enhancing effect by raising the load point until acoustic limits are reached which are ascertained in real time, can be predefined in a variable manner and are defined in accordance with ascertained potentials for masking specific acoustic events. The disclosed method and device for carrying out the method raise the acoustic limits for controlling the load point of the internal combustion engine at least to the level that is currently admissible as a result of at least one acoustically relevant event being masked, possible acoustically relevant events being defined by vehicle-internal sources of influence, the characteristic spectra of which are known from empirical assessments and the occurrence of which is controlled by vehicle-internal systems.

Claims

1. A method for operating a hybrid vehicle having an electric energy store, an electric drive and an internal combustion engine, the method comprising the acts of: determining an acoustic masking potential of at least one acoustic event, wherein the at least one acoustic event includes a first acoustic event defined by vehicle-internal sources controlled by vehicle-internal systems; determining an acoustic limit for the internal combustion engine, wherein the acoustic limit is below the acoustic masking potential; determining a load point for the internal combustion engine such that a load-dependent sound spectrum of the internal combustion engine matches the acoustic limit, and such that operating the internal combustion engine at the load point generates excess torque; operating the internal combustion engine at the load point so as to generate the excess torque; and charging the electric energy store using the excess torque generated by operating the internal combustion at the load point.

2. The method as claimed in claim 1, wherein the masking potential is an overall masking potential of a plurality of current acoustic events, each having different individual masking potentials.

3. The method as claimed in claim 2, wherein determining the overall masking potential involves the maximum of all simultaneously available masking potentials.

4. The method as claimed in claim 2, wherein the individual masking potentials and/or the overall masking potential are prescribed in the form of sound pressure spectra.

5. The method as claimed in claim 1, wherein the acoustic limit is below a basic acoustic limit of the internal combustion engine.

6. The method as claimed in claim 1, wherein the at least one acoustic event includes a second acoustic event defined by vehicle-external sources whose occurrences are capturable by sensors.

7. The method as claimed in claim 6, wherein the second acoustic event includes output signals from audio installations.

8. The method as claimed in claim 7, wherein the second acoustic event is defined by an unknown source and is captured via at least one microphone, and wherein the masking potential is determined to be brief and in accordance with basis of the expected high signal dynamics.

9. A computer product comprising a non-transitory computer readable medium having stored thereon program code segments that, when executed by a processor of an electronic control unit, carry out the acts of: determining an acoustic masking potential of at least one acoustic event, wherein the at least one acoustic event includes a first acoustic event defined by vehicle-internal sources controlled by vehicle-internal systems; determining an acoustic limit for the internal combustion engine, wherein the acoustic limit is below the acoustic masking potential; determining a load point for the internal combustion engine such that a load-dependent sound spectrum of the internal combustion engine matches the acoustic limit, and such that operating the internal combustion engine at the load point generates excess torque; operating the internal combustion engine at the load point so as to generate the excess torque; and charging the electric energy store using the excess torque generated by operating the internal combustion at the load point.

10. A hybrid vehicle, having: an electronic control unit; and a non-transitory computer readable medium having stored thereon program code segments that, when executed by a processor of the electronic control unit, carry out the acts of: determining an acoustic masking potential of at least one acoustic event, wherein the at least one acoustic event includes a first acoustic event defined by vehicle-internal sources controlled by vehicle-internal systems; determining an acoustic limit for the internal combustion engine, wherein the acoustic limit is below the acoustic masking potential; determining a load point for the internal combustion engine such that a load-dependent sound spectrum of the internal combustion engine matches the acoustic limit, and such that operating the internal combustion engine at the load point generates excess torque; operating the internal combustion engine at the load point so as to generate the excess torque; and charging the electric energy store using the excess torque generated by operating the internal combustion at the load point.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic depiction of an overview of the essential components of the invention.

(2) FIG. 2 is an example of a first individual masking potential.

(3) FIG. 3 is an example of a second individual masking potential.

(4) FIG. 4 is an example of a third individual masking potential.

(5) FIG. 5 is an example of a fourth individual masking potential.

(6) FIG. 6 is a graph for the inventive ascertainment of a new overall-masking-dependent acoustic limit in the case of overlaid masking potentials according to the aforementioned option II.

DETAILED DESCRIPTION OF THE DRAWINGS

(7) FIG. 1 depicts an input/output display 1 at least for the output of information pertaining to the specific method of operation according to the invention. The display 1 is actuated via an electronic control unit 7. The current state of charge SOC of an electric energy store 2, in this case a high-voltage battery, is captured and forwarded to the display 1.

(8) A further input signal for the control unit 7 will be the status of an air conditioning fan 3, for example, in this case as an example of a possible acoustically relevant event by a vehicle-internal source of influence whose characteristic spectrum is known and whose occurrence is controlled by a vehicle-internal system, in this case the air conditioning system. The masking potential of the air conditioning fan 3 is indicated by M1.

(9) A further input signal for the control unit 7 will be the status of a sensor arrangement 4 for detecting travel through a tunnel, for example, in this case as an example of a possible acoustically relevant event by a vehicle-external source of influence whose characteristic spectrum is known and whose occurrence is capturable by sensors, in this case by a camera in conjunction with a navigation system, for example. The masking potential of detected travel through a tunnel is indicated by M2.

(10) A further input signal for the control unit 7 will be the signal from an audio installation 5, for example, in this case as an example of a possible acoustically relevant event by a user-caused source of influence whose characteristic spectrum is evaluable before or during reproduction. The masking potential of the current output from an audio installation 5 is indicated by M3.

(11) A further input signal for the control unit 7 will be the input signal from a microphone 6, for example, in this case as an example of a possible acoustically relevant event by an unknown source of influence whose characteristic spectrum is unknown beforehand and is ascertainable only highly dynamically. The masking potential of the airborne sound spectrum currently captured by means of the microphone 6 (for example a conversation by vehicle occupants) is indicated by M4.

(12) The masking potentials M1 to M4 are ascertained in a functional module 8 of the controller 7 and if need be coordinated.

(13) The individual masking potential M1 of the air conditioning fan 3 is depicted by way of example in FIG. 2.

(14) The individual masking potential M2 of detected travel through a tunnel is depicted by way of example in FIG. 3.

(15) The individual masking potential M3 of the current output for an audio installation 5 is depicted by way of example in FIG. 4.

(16) The individual masking potential M4 of the airborne sound spectrum currently captured by means of the microphone 6 is depicted by way of example in FIG. 5.

(17) The masking potentials are depicted in decibels [dB] in this case and relative to a basic acoustic threshold BA in this case.

(18) FIG. 6 uses an example graph to show the mode of action of the coordination method according to the invention performable by virtue of appropriate programming of the functional module 8. In this case, a (one-third octave) sound pressure spectrum of the audio installation 5, or the masking potential M3, and a (one-third octave) sound pressure spectrum as a result of traveling through a tunnel, or the masking potential M2, are depicted, which together form a new (one-third octave) spectrum or a cumulative masking potential MAX (M2, M3) or an overall sound pressure spectrum (denoted by the bold line).

(19) Subsequently, it is ascertained how high the order level of the internal combustion orders is that can be masked by this overall sound spectrum. Stored data are then used to convert this order level into a motor torque in newton meters [Nm]. At the end of this partial process, the matching with the basic acoustic limit BA then takes place, in [Nm], if need be, said basic acoustic limit being dependent on the static vehicle properties and operating points of vehicle and drive.

(20) The basic acoustic limit BA can be prescribed preferably when none of the other masking potentials M1 to M4 are available.

(21) In a particular configuration of the invention, when there is a specific reason, it is also possible for a lower acoustic limit, which may even be beneath the basic acoustic limit, to be prescribed on the basis of or independently of the occurrence of a masking acoustically relevant event. This prevention or reduction of the raising of the load point or this lowering of the load pointeven below the basic acoustic limit or independently of a basic acoustic limitcan be regarded not only as a development of the invention but also as an independent concept. By way of example, a lowering of the load point can be used as an extended mute function for a telephone call. In this case, depending on the state of charge, it would also be possible to change over to full electric driving.

(22) The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.