motor vehicle

Abstract

Motor vehicle (KFZ) - with a brake light (BL), - with a service braking system (BB) for effecting automatic braking, - with an energy recovery deceleration system (EB) to effect recuperative deceleration, - with a control device (STE) which is configured and coupled to the brake light (BL), the service brake system (BB) and the energy recovery deceleration system (EB), - that the brake light (BL) is automatically switched on when deceleration occurs, depending on the deceleration of the motor vehicle, - that the brake light (BL) is automatically switched off when automatic braking is initiated if the deceleration of the motor vehicle falls below a predetermined switch-off threshold for automatic braking, - that the brake light (BL) is automatically switched off when regenerative deceleration is effected if the deceleration of the motor vehicle falls below a predetermined switch-off threshold for regenerative deceleration, and - that the brake light (BL) is automatically switched off during a transition from automatic braking to regenerative deceleration if the deceleration of the motor vehicle falls below a predetermined switch-off threshold which is different from the switch-off threshold for regenerative deceleration and, in particular, corresponds to or is identical to the switch-off threshold for automatic braking.

Description

The invention relates to a motor vehicle having a brake light, having a service brake system for causing automatic braking and having an energy recovery deceleration system for causing a regenerative deceleration.Motor vehicles with a brake light and a service brake system for causing a deceleration initiated by a driver are known, in which the brake light is automatically switched on when causing a deceleration as a function of the deceleration of the motor vehicle, and in which the brake light is automatically switched off when causing a deceleration if a deceleration of the motor vehicle falls below a predefined switch-off threshold.More recent technological advances provide that the service brake system is also or exclusively used to effect automatic, in particular autonomous, braking. Within the scope of the invention, automatic braking is in particular braking that is automatically triggered or controlled, for example within the scope of a driver assistance system, on the basis of a driving situation detected by sensors of the motor vehicle.In addition, vehicles having an energy recovery deceleration system, for example an electrical deceleration system having an energy recovery device, for causing a regenerative deceleration are proposed.Prior art document relating to the field of the present invention is known from DE 10 2008 055 898 A1, DE 10 2010 004 846 A1 and DE 199 20 096 B4.The object of the invention is to specify a motor vehicle which is improved compared to the prior art.This object is achieved by the features of the independent claim. Advantageous further developments of the invention can be found in the dependent claims.A motor vehicle according to the invention has a brake light, a service brake system for causing automatic braking, an energy recovery deceleration system, in particular an electrical deceleration system with energy recovery device, for causing a regenerative deceleration, and a control device which is coupled to the brake light, the service brake system and the energy recovery deceleration system.The control device, preferably a processor device, a control device or a combination of control devices (for example engine control device and driving stability control device) coupled to one another in terms of data technology, is configured in terms of hardware and / or program technology in such a way that the brake light is automatically switched on (activated) when causing, in particular performing, an automatic braking or regenerative deceleration as a function of the deceleration of the motor vehicle, that the brake light is automatically switched off (deactivated) when causing, in particular performing, an automatic braking if a deceleration of the motor vehicle falls below a predefined, in particular speed-dependent, switch-off threshold for automatic brakings, that the brake light is automatically switched off (deactivated) when causing, in particular performing, a regenerative deceleration (in particular when causing a regenerative deceleration in which automatic braking is not also simultaneously performed), if a deceleration of the motor vehicle falls below a predefined, in particular speed-dependent, switch-off threshold for regenerative decelerations, and if a deceleration of the motor vehicle falls below a predefined, in particular speed-dependent, switch-off threshold for regenerative decelerations, and if the brake light is automatically switched off (deactivated) during a transition from automatic braking to a regenerative deceleration, said brake light differing from the switch-off threshold for regenerative decelerations, which corresponds in particular to the switch-off threshold for automatic brakings or is identical thereto.A transition from automatic braking to a regenerative deceleration is preferably present if during automatic braking the regenerative deceleration is already carried out before a deceleration of the motor vehicle falls below the switch-off threshold for automatic braking, in particular before the brake light is switched off due to the switch-off threshold for automatic braking being undershot.In the context of the invention, the amount of the ascertained acceleration of the motor vehicle is considered to be deceleration, the ascertained acceleration being negative in the event of a deceleration of the motor vehicle. The switch-on or switch-off thresholds are likewise each an amount of a predefined negative acceleration.The predetermined switch-on and switch-off thresholds are preferably all or partially speed-dependent. The predefined switch-on and switch-off thresholds are preferably predefined in a manufacturer-specific manner or in a vehicle-type-specific manner within the limits of internationally agreed, uniform technical regulations for motor vehicles, such as ECE regulations, for example. In the latter case, the predetermined switch-on and switch-off thresholds are preferably selected from switch-on and switch-off threshold bands, which are in turn predetermined by internationally agreed, uniform technical regulations for motor vehicles, such as ECE regulations.In addition to automatic braking, the service brake system may also be provided for causing braking initiated by a driver.It is of course within the scope of the invention if the teaching according to the invention is used only in specific driving situations, only in specific braking or deceleration situations or only in specific speed ranges.The invention is based on the finding that, when internationally agreed, uniform technical regulations are used for switch-off thresholds, constellations can occur in which a brake light switched on due to automatic braking is switched off, for example with constant deceleration in a transition to a regenerative deceleration, because the regulations mentioned allow higher switch-off thresholds for regenerative decelerations than for the automatic brakings. A driver of a following vehicle would, however, in this case start from a decreasing deceleration due to the switching off of the brake light. This erroneous acceptance of the driver of the following vehicle represents a safety risk, however, due to the actually constant deceleration.The invention achieves the effect that a brake light which is switched on once as a result of automatic braking is not switched off in accordance with the possibly excessively high switch-off thresholds for regenerative deceleration when a transition to a regenerative deceleration is made, but rather is switched off in accordance with switch-off thresholds which differ therefrom. This makes it possible to achieve that the deceleration-dependent switch-off behavior of the brake light corresponds to the expectation of other road users.In a further development of the invention, the brake light is automatically switched on when automatic braking is effected if a deceleration of the motor vehicle exceeds a predefined, in particular speed-dependent, switch-on threshold for automatic braking, and / or the brake light is automatically switched on when a deceleration of the motor vehicle exceeds a predefined, in particular speed-dependent, switch-on threshold for regenerative decelerations.In another development of the invention, the brake light is automatically switched off in the event of a transition from automatic braking to a regenerative deceleration and / or in the event of a transition from a regenerative deceleration to automatic braking, if a deceleration of the motor vehicle falls below a predefined, in particular speed-dependent, switching-off threshold which differs from the switching-off threshold for regenerative decelerations, which in particular corresponds to the switching-off threshold for automatic brakings or is identical thereto.This also makes it possible to achieve the effect that the deceleration-dependent switch-off behavior of the brake light corresponds to the expectation of other road users, in particular also in the case of a transition from a regenerative deceleration to an automatic braking operation.The motor vehicle according to the invention preferably comprises a deceleration determination device for determining the current deceleration and / or a speed determination device for determining the current speed.In order to prevent flickering of the brake light, provision can preferably be made for:during automatic braking, in the event that a regenerative deceleration is already being carried out, and the deceleration falls below the switch-off threshold for automatic braking, the brake light still remains switched on for a predefined period of time, and / orin the event of a regenerative deceleration, if automatic braking is already being carried out, and if the deceleration falls below the switch-off threshold for regenerative deceleration, the brake light still remains switched on for a predefined period of time, and / orin the event of a transition from automatic braking to a regenerative deceleration, in the event that automatic braking is already being carried out and the deceleration falls below the switch-off threshold for automatic decelerations, the brake light remains switched on for a predefined period of time.The invention is explained in more detail below with reference to examples with reference to the following figure: FIG. 1 shows a simplified schematic diagram of a motor vehicle having a deceleration system and a stop light.The motor vehicle KFZ illustrated in FIG. 1 has a brake light system BL known per se, a service brake system BB known per se for causing automatic braking, for example for causing a dynamic intervention of a driver assistance system or an electronic driving stability control, and an energy recovery deceleration system EB known per se for causing a regenerative deceleration.In addition, a deceleration determination device VE known per se and a speed determination device GE are provided, which can both be based on a sensor system for the wheel speeds and can be realized by means of a computer unit.For carrying out the invention, the control device STE is provided which is set up in a program-related manner and is connected in terms of data via a data bus system known per se to the brake light BL, the deceleration determination device VE, the speed determination device GE, the service brake system BB and the energy recovery deceleration system EB in such a way that the brake light BL is automatically switched on and off as a function of the current speed, as a function of the current deceleration and as a function of the current operating state and the operating state transitions of the two deceleration systems BB, EB.The switching behavior of the brake light BL is defined by predefined speed-dependent switch-on and switch-off thresholds, which can be stored, for example, in the control device STE.It is of course within the scope of the invention that instead of the deceleration signals correlating therewith, such as wheel brake torques or wheel brake pressures, are used as the basis for the switching behavior of the brake light BL, and the switch-on and switch-off thresholds are then not deceleration values but wheel brake torque values or wheel brake pressure values. The disadvantage of this is the scattering behavior due to external influences such as the loading state of the motor vehicle or fluctuations in the brake lining coefficients of friction.An exemplary switching-on and switching-off behavior of the brake light is explained below on the basis of predefined speed-dependent switching-on and switching-off thresholds:the brake light BL is automatically switched on when automatic braking is effected if a deceleration of the motor vehicle exceeds a predetermined switch-on threshold for automatic braking,the brake light BL is automatically switched on when a regenerative deceleration is effected if a deceleration of the motor vehicle exceeds a predetermined switch-on threshold for regenerative decelerations,the brake light BL is automatically switched off when automatic braking is effected if a deceleration of the motor vehicle falls below a predefined switch-off threshold for automatic braking,the brake light BL is automatically switched off when a regenerative deceleration is effected if a deceleration of the motor vehicle falls below a predefined switch-off threshold for regenerative decelerations (a transition from an automatic braking operation to a regenerative deceleration before the deceleration falls below a switch-off threshold for automatic braking operations is not understood as an effect of a regenerative deceleration in this sense),Deviating from the last paragraph, the brake light BL is automatically switched off in the event of a transition from automatic braking to a regenerative deceleration if a deceleration of the motor vehicle falls below a predefined switching-off threshold which differs from the switching-off threshold for regenerative decelerations, which corresponds in particular to the switching-off threshold for automatic brakings or is identical thereto.In the event of a transition from automatic braking to a regenerative deceleration, therefore, the switch-off threshold for regenerative deceleration is not decisive for the switch-off behavior of the brake light BL, but rather a switch-off threshold deviating therefrom is decisive, in particular a lower switch-off threshold than the switch-off threshold for regenerative decelerations. Preferably, the switch-off threshold for automatic braking is used as the switch-off threshold in this case.A transition from a regenerative deceleration to an automatic braking is assumed if the regenerative deceleration is already carried out before an automatic braking. In this case, the brake light BL is automatically switched off when a deceleration of the motor vehicle falls below a predefined switch-off threshold for the automatic braking.A preferred embodiment variant which is independent of the examples mentioned provides that during automatic braking, in the event that a regenerative deceleration is already carried out and that the deceleration falls below the switch-off threshold for automatic decelerations, the brake light still remains switched on for a predefined period of time.Alternatively or additionally, it is provided that in the case of a regenerative deceleration, in the event that automatic braking is already being carried out and that the deceleration falls below the switch-off threshold for automatic decelerations, the brake light still remains switched on for a predefined period of time.This may possibly prevent an undesired flickering of the brake light.

Claims

Motor vehicle (KFZ) - with a brake light (BL), - with a service brake system (BB) for causing automatic braking, - with an energy recovery deceleration system (EB) for causing a regenerative deceleration, - with a control device (STE) which is set up in such a way and is coupled to the brake light (BL), the service brake system (BB) and the energy recovery deceleration system (EB), - in that the brake light (BL) is automatically switched on when causing a deceleration as a function of the deceleration of the motor vehicle, - in that the brake light (BL) is automatically switched off when causing automatic braking if a deceleration of the motor vehicle falls below a predefined switch-off threshold for automatic brakings, the brake light (BL) is automatically switched off when causing a regenerative deceleration if a deceleration of the motor vehicle falls below a predefined switch-off threshold for regenerative deceleration, and the brake light (BL) is automatically switched off when a transition from automatic braking to a regenerative deceleration occurs if a deceleration of the motor vehicle falls below a predefined switch-off threshold which differs from the switch-off threshold for regenerative deceleration, which corresponds in particular to the switch-off threshold for automatic brakings or is identical thereto.Motor vehicle (KFZ) according to Claim 1, - in that the brake light (BL) is automatically switched on when automatic braking is effected if a deceleration of the motor vehicle exceeds a predefined switching-on threshold for automatic brakings, and / or - in that the brake light (BL) is automatically switched on when a deceleration of the motor vehicle exceeds a predefined switching-on threshold for regenerative deceleration.Motor vehicle (KFZ) according to one of the preceding claims, characterized in that the brake light (BL) is automatically switched off in the event of a transition from automatic braking to a regenerative deceleration and / or in the event of a transition from a regenerative deceleration to automatic braking, if a deceleration of the motor vehicle falls below a predefined switching-off threshold which differs from the switching-off threshold for regenerative decelerations, which in particular corresponds to the switching-off threshold for automatic brakings or is identical thereto.Motor vehicle (KFZ) according to one of the preceding claims, having a deceleration determination device (VE) and having a speed determination device (GE).Motor vehicle (FC) according to one of the preceding claims, in which, during automatic braking, in the event that a regenerative deceleration is already carried out and that the deceleration falls below the switch-off threshold for automatic brakings, the brake light remains switched on for a predefined period of time.Motor vehicle (FC) according to one of the preceding claims, in which, in the case of a regenerative deceleration, in the event that automatic braking is already carried out and that the deceleration falls below the switch-off threshold for regenerative decelerations, the deceleration light still remains switched on for a predefined period of time.Motor vehicle (FC) according to one of the preceding claims, in which, in the event of a transition from automatic braking to a regenerative deceleration, in the event that automatic braking is already being carried out and that the deceleration still falls below the switch-on threshold for regenerative decelerations, the brake light still remains switched on for a predefined period of time.

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