Method for Controlling a Heating/Air-Conditioning Component

Abstract

A method controls a heating/air-conditioning component of a hybrid vehicle. In the event of undershooting a minimum state-of-charge of a drive battery, operation of the heating/air-conditioning component is enabled, provided that sufficient electric power is fed to the drive battery such that no further discharging of the drive battery occurs. A hybrid vehicle includes a control device which is appropriate for executing the method.

Claims

1. A method for controlling a heating/air-conditioning component of a hybrid vehicle, comprising: in an event of undershooting a minimum state-of-charge of a drive battery, enabling operation of the heating/air-conditioning component, provided that sufficient electric power is fed to the drive battery such that no further discharging of the drive battery occurs.

2. The method according to claim 1, further comprising: controlling a heating/air-conditioning component in the form of an air-conditioning compressor.

3. The method according to claim 1, wherein for such time as the minimum state-of-charge is undershot, enabling the operation of the heating/air-conditioning component at a reduced capacity only, which reduced capacity is restricted in relation to operation above the minimum state-of charge.

4. The method according to claim 3, wherein the minimum state-of-charge is lower than 15% of a maximum state-of-charge of the drive battery.

5. The method according to claim 1, wherein electric power is fed to the electric drive battery from an alternator, which is driven by a combustion engine.

6. A hybrid vehicle comprising a control device operatively configured to enable operation of a heating/air-conditioning component in an event of undershooting a minimum state-of-charge of a drive battery, provided that sufficient electric power is fed to the drive battery such that no further discharging of the drive battery occurs.

7. The hybrid vehicle according to claim 6, wherein the heating/air-conditioning component is an air-conditioning compressor.

8. The hybrid vehicle according to claim 6, wherein for such time as the minimum state-of-charge is undershot, the control device enables the operation of the heating/air-conditioning component at a reduced capacity only, which reduced capacity is restricted in relation to operation above the minimum state-of charge.

9. The hybrid vehicle according to claim 8, wherein the minimum state-of-charge is lower than 15% of a maximum state-of-charge of the drive battery.

10. The hybrid vehicle according to claim 6, further comprising a combustion engine and an alternator, wherein electric power is fed to the electric drive battery from the alternator, which is driven by the combustion engine.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0013] FIG. 1 is a flowchart illustrating a preferred exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWING

[0014] FIG. 1 shows a schematic flow diagram of the method according to the invention, according to an exemplary embodiment of the invention. This method can be implemented, for example, in the form of a computer program, which is saved on a control device or on a data memory which is assigned to the control device. The control device is installed in a hybrid vehicle, i.e. in a motor vehicle, which incorporates both a combustion engine and at least one electric motor for the propulsion of the motor vehicle. The hybrid vehicle moreover has a rechargeable drive battery, which stores electrical energy by an electrochemical method and delivers the latter, at least for the propulsion of the motor vehicle and for at least one heating/air-conditioning component.

[0015] The heating/air-conditioning component is particularly an air-conditioning compressor of an air-conditioning system and/or an electric interior heater for the heating of a vehicle interior of the hybrid vehicle.

[0016] The method progressively determines whether a battery charge of the drive battery has fallen below a specified minimum state-of-charge (step S1). The minimum state-of-charge refers to the predetermined threshold value for the battery charge, in relation to a maximum state-of-charge, in kilowatt-hours (kWh). This threshold value for the minimum state-of-charge is determined by reference to safety aspects, which define the residual charge which, for reasons of safety (for example, for the supply of safety-critical vehicle components) and for the protection of the drive battery (fully-discharged drive batteries can age more rapidly), is still present and should not be undershot. If this is not the case (“no”), the heating/air-conditioning component is normal, and is employable with no capacity reduction (step S2). The control process then returns to step S1. This can be executed in the form of a continuous check, or determined at regular time intervals.

[0017] If it proceeds from step S1 that the minimum state-of-charge has been undershot, the control process, by means of measuring sensors, then determines whether the drive battery is already being recharged, and particularly is being recharged by the operation of the combustion engine (step S3). It is also determined whether the drive battery is charged with sufficient energy to permit the operation of the heating/air-conditioning component. In other words, the charge capacity is required to exceed a minimum value, i.e. the charge capacity must at least be of sufficient magnitude for the operation of the heating/air-conditioning component at reduced capacity. If this is not the case (“no”), the control process then proceeds to step S4, and the heating/air-conditioning component is deactivated, or remains deactivated, if it has already been deactivated. This prevents any significant discharging of the drive battery below the minimum level of charge. The safety of the vehicle is thus enhanced, as a residual charge is maintained for safety reasons.

[0018] If it proceeds from the query in step S3 that the drive battery has been sufficiently charged to at least permit the maintenance of the state-of-charge, the control process then proceeds to step S5, in which the employment of the heating/air-conditioning component is permitted with a reduced capacity. The term “reduced” relates to a normal state, for example as per step S2. For example, the reduced capacity of the heating/air-conditioning component is no more than 70% of the maximum capacity of this component.

[0019] The control process then returns to step S1, such that the control process, in the event of a change such as, for example, a sufficient state-of-charge of the drive battery, or a declining charging current, can react correspondingly.

[0020] The present invention thus provides an advantage in that, in the event of a near-discharged battery and with the combustion engine running, it is not necessary for a vehicle occupant to wait until a specific minimum state-of-charge has been exceeded, which might take a number of minutes, but rather the heating/air-conditioning component is available immediately, in the event of a sufficient charging current, thereby enhancing comfort in a substantially cooled or overheated vehicle.

[0021] Although the invention has been illustrated and described in detail in the drawing and in the preceding description, this illustration and description are to be understood as exemplary only, and not by way of limitation, and it is not intended to limit the invention to the exemplary embodiment disclosed. The simple fact that particular features are described in various dependent claims does not signify that an advantageous exploitation of a combination of these features is excluded.

[0022] 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.