DE102007021242A1 - Device for break light control in vehicle, has break system, control device for controlling vehicle break system and break light controlled by control device or by separate controller - Google Patents

Abstract

The device has a break system formed, a control device for controlling the vehicle break system and a break light controlled by the control device or by a separate controller. The control device or the controller is formed such that switching-on the break light during automatic break application under a predetermined speed limit warning depends on a break pressure established in the activated vehicle break or depends on a correlative magnitude affected with the break pressure.

Description

The The invention relates to a device for brake light control according to the preamble of claim 1.

From the DE 199 20 096 A1 A device for brake light control in a motor vehicle is already known in which an automatic control of the brake lights takes place during automatic (power-operated) braking operations. This device has already proven itself many times.

Of the Invention is based on the object, a generic device to improve the brake light control on, in particular a brake light control indicate, even in a lower speed range of the vehicle, especially in a speed range close the vehicle standstill, a reliable indication of a braking process guaranteed becomes. In particular, a brake light flicker should be avoided.

According to the invention Problem solved by the entirety of the features of claim 1, while in the dependent claims preferred developments of the invention are given. mandatory requirement for a brake light control according to the invention is the presence of an automatic (not manually over the Driver initiated) braking operation. Other mandatory requirement is the falling below or reaching a predetermined threshold speed threshold and the passing a predetermined pressure threshold in at least one hydraulic circuit of activated vehicle brake, in which the brake light is activated should.

The inventive device for brake light control includes a control unit for this purpose the vehicle brakes and at least one via the control unit or via a separate control device (hereinafter referred to uniformly as control device) controllable brake light. In this case, the control unit is such trained that in dependence of vehicle operating conditions an automatic braking operation (power-operated braking operation) feasible is. The control unit is according to the invention designed to turn on the brake light during a automatic braking, below a predetermined limit speed, dependent on from a brake pressure determined in the activated vehicle brake or depending from a correlated with the brake pressure size. Below the predetermined Limit speed (limit speed threshold) becomes the brake light (the at least one brake light) depending on the brake pressure the activated vehicle brake or a correlated herewith Size (measured or calculated or estimated quantities, such as: Braking torque, braking force on the wheel, or the like) is turned on. Preferably, the control of the brake light takes place below the speed threshold exclusively depending from the brake pressure or the used correlated with the brake pressure Size. With advantage is the predetermined threshold speed threshold above the Vehicle speed zero arranged.

Above the limit speed threshold, the control of the brake light takes place (Switch on / off) different, with advantage in dependence from the (eg over Acceleration sensors) determined vehicle deceleration.

The predetermined threshold speed threshold is in a preferred Embodiment of Applicable invention. In particular, the limit speed threshold dependent on from the vehicle speed (e.g., the current actual vehicle speed at the start time of the braking process or averaged over a time window Speed up to the start time of the braking process) and / or the inclination of the vehicle about its transverse axis (e.g., due to the road incline) automatically changeable.

To the Turning on and off the brake light in the speed range below the predetermined limit speed threshold is a Switch-on brake pressure threshold or on - preferably from the switch-on brake pressure threshold different - switch-off brake pressure threshold specified. Advantageously, the switch-off brake pressure threshold is a predetermined one Pressure difference less than the switch-on brake pressure threshold, so that's a big enough one Switching hysteresis is ensured. Once on the brake light in the lower speed range (speed range below the predetermined limit speed threshold) remains thereby for one reasonable time is turned on and a brake light flickering safely avoided. In a possible Further development of the invention may be a brake pressure threshold or Both brake pressure threshold values can be designed to be applicable. With Advantage is a change a brake pressure threshold also depending on the vehicle speed and / or the vehicle inclination angle and / or the vehicle weight. In order to bridge any pressure drops, there may still be a minimum follow-up time implemented applicably when falling below the brake pressure threshold become.

In order to produce a brake light signal which seems plausible to the following traffic, the brake light is preferably switched on only when the switch-on conditions for a predetermined period of time applied continuously. If the absence of at least one switch-on condition is detected within the time duration, even if only for a short period of time, the time for the monitoring process (without the brake light being switched on) starts again (resetting of a timer module).

Becomes the vehicle over stopping an automatic braking process are different Controlling the brake light (especially the so-called third, i.d.R. in the rear window area arranged brake light) conceivable. In a first version is provided, the at least one switched brake light permanently kept on until a new restart process is detected or until the vehicle is deactivated (switched off) by switching off the ignition is or until by manually switching off (actuation of a switching element for activation or deactivation of the function by the vehicle occupant) the function which activates the automatic brake function is deactivated becomes.

In a second embodiment is provided, the at least one brake light for a predetermined Time after standstill to keep turned on and only after Expiration of this period or a recognized restart process or a recognized parking of the vehicle or by manual Switching off the function (see above) the at least one brake light turn off again.

Furthermore each additional criteria are considered. For example may be a vehicle rear space monitoring device be provided and the control unit be designed such that the at least one brake light is switched off, if over the monitoring device one in the vehicle rear space entering or approaching one's own vehicle Other vehicle has detected. Advantageously, the at least one brake light after detection of a foreign vehicle in the vehicle rear still for a predetermined Duration kept switched on and after this period of time switched off.

Further may be the vehicle rearview monitoring device in conjunction with the control unit be designed so that in a nourishing Foreign vehicle, which moves at a speed above one predetermined limit speed approaches the (own) vehicle, a Switching the brake light to a second brake light stage takes place. In this second brake light stage, e.g. the brightness of the activated Brake lights increased be and / or the illuminated area the brake lights are increased and / or additional Brake lights are activated and / or the hazard warning lights activated become.

Of Further, the at least one brake light also in dependence from the presence of a lane slope permanently or for remain switched on for a predetermined period of time (at the latest the switch-off takes place in each case at the next restart process or at the deactivation of the vehicle).

By the proposed shutdown or switching scenarios can be in different Situations an unnecessary one Dazzling avoided by other road users and an early Warning be made.

In a development of the control unit with regard to the brake light switch-off can the controller be coupled with a navigation system and the shutdown the at least one brake light depending on the over Navigation system determined environment type done. It can For example, a distinction between urban and out-of-town and can for the different ones Environments different types of shutdown can be selected. Alternatively or additionally can also be dependent from the determined road type (City street, Highway, Highway) or the current speed limits a shutdown be assigned. In this case, the determination of the permissible maximum speed over the Navigation system or over other recognition systems (e.g., camera systems, traffic guidance systems, o.d.) to determine the maximum speed limit respectively.

Farther can during automatic braking with very high system delay levels, e.g. during automatic braking on highways, the hazard warning lights are additionally switched on, as soon as a correspondingly strong deceleration level is reached. Alternatively, the activation of the hazard warning lights but also after completed delay phase with a correspondingly strong deceleration level, so while a standstill phase of the vehicle to be activated.

Of the Brake pressure, depending on it the brake light is controlled, is beneficial over a Pressure sensors of the brake hydraulics or via a brake pressure calculation model determined.

If, during an automatic braking operation, the predetermined limit speed at which a brake light control is to be pressure-dependent (instead of delay-dependent, for example) is undershot, the brake light is already activated (or switched on), so that only the switch-off conditions are pressure-dependent controlled. For the Cases where, for example, braking operations are initiated below the predetermined limit speed in a stop-and-go operation with automated start and brake operations, both the switching on and the switching off of the brake lights is pressure-dependent.

The mode of action of the device according to the invention is based on the 1 - 3 will be explained in more detail below. Show it:

1 : the brake pressure curve during a possible automatic braking process in a motor vehicle,

2 : a possible, due to the brake pressure curve according to 1 resulting, brake light control,

3 : another possible, due to the brake pressure curve according to 1 resulting, brake light control,

4 a further (second) possible brake pressure curve during an automatic braking process in a motor vehicle,

5 : from automatic braking according to 4 resulting vehicle deceleration,

6 : a possible, due to the brake pressure curve according to 4 resulting, brake light control,

7 a further (third) possible brake pressure curve during an automatic braking process in a motor vehicle,

8th : from automatic braking according to 7 resulting vehicle deceleration, and

9 : a possible, due to the brake pressure curve according to 7 resulting, brake light control.

1 shows a possible pressure curve (K1) of a brake pressure in the hydraulic circuit of a, activated during an automatic braking, vehicle brake. A prerequisite for the brake light control according to the invention is the undershooting of a predetermined threshold speed threshold (or the presence of a vehicle speed less than or equal to the predetermined threshold speed threshold) during an automatic braking operation. In the present example, the presence of a vehicle speed below this speed threshold is assumed.

At the time t0, for example, via a driver assistance system, such as a distance-dependent cruise control (in the case of BMW vehicles known as ACC or active cruise control), an automatic braking process is initiated or the automatic brake system is activated. A short time later, according to the embodiment, at time t _1, the predetermined (advantageously applicable) pressure threshold SEN for switching on the at least one brake light is reached and the brake light (one or more brake lights) is turned on. Until the time t ₂ , the brake pressure fluctuates around the switch-on threshold S _Ein , but never falls below the switch-off threshold S _Aus . From time t ₂ , different situations are alternatively assumed.

According to a first situation, it is assumed that the vehicle was decelerated to standstill at the time t2 by the automatic braking operation. This is followed by an automatic construction of a brake pressure reserve up to a predetermined brake pressure p _res , which is then maintained until the next restart process. This process is shown in the dashed curve section K1 '. In 2 is analogous to this, a possible brake light control shown, the brake light is switched on at time t1 and at time t ₃ , when reaching the pressure reserve p _res , off. In alternative embodiments, the elimination of the brake light, as already described above, different (even at a later date) take place.

According to a second situation, it is assumed that the vehicle continues to creep over time t ₂ until the automatic braking operation has ended at time t ₅ . At the time t ₅ , at the time t _4, the switch-off brake pressure threshold S _{Aus is} undershot and the brake light is switched off before the end of the automatic braking process. This process is shown in the non-dashed curve section K1 "from the time t ₂ . In 3 a possible brake light control is shown analogous to this braking process course, wherein the brake light is switched on at the time t ₁ and off at the time t ₄ falls below the switch-off brake pressure threshold S _Aus . Again, the actual turn-off, as described above, can be configured differently. In order to bridge possibly occurring undershoot pressure, the brake light is switched off only after the expiry of a timer, which is started upon reaching the switch-off threshold.

Based on the embodiment according to the 1 - 3 can (especially in an automated distance-controlled follow-up drive in the ACC mode in the lower speed range) nor other types of typical driving situations occur, which are explained in more detail below.

In the 4 - 6 is illustrated a driving situation in which, during the adjusting due to the automatic braking operation vehicle deceleration, the automatically set brake pressure despite further delay to zero (zero brake pressure) degraded and immediately afterwards rebuilt to the preceding vehicle according to the distance and speed control to react. In this situation, however, the brake light should not be switched off and immediately switched on again. Such a brake light back-and-forth can be avoided by the brake light remains switched on for a predetermined period of time even after dissolved brake pressure (falling below the switch-off or zero brake pressure). If the vehicle is decelerated, after falling below the switch-off threshold S _Off, a (time) counter with a predetermined follow-up time T _{follow-up is} activated. During this time window with the time T _lag , the brake light remains activated. If the brake pressure is automatically increased again within the follow-up time T _trailing by the driving function (eg distance / speed control ACC) and, for example, exceeds the predetermined switch-off threshold S _Off , the counter is reset and the brake light remains activated. If the switch-off threshold S _{out is} not reached or exceeded within the follow-up time T _follow-up , the brake light is switched off.

4 shows analogously to 1 a further possible pressure curve (K10) of a brake pressure in the hydraulic circuit of an activated during a braking process vehicle brake. Analogously, the same boundary conditions apply here as in the example according to FIG 1 , At the time t ₀₀ , an automatic braking process is again initiated, so that a brake pressure is automatically set as a function of vehicle operating conditions according to the curve K10 by the activated brake system. Parallel to the brake pressure of the brake system is in the 4 with the curve Kv the vehicle speed and is in the 5 the curve Ka represents the self-adjusting vehicle deceleration of the vehicle. As a result of the brake activation at the time t ₀₀ , a vehicle deceleration according to the curve Ka occurs in parallel from this point in time. At time t ₁₀ , the brake pressure reaches the predetermined switch-on threshold S _Ein for activating the brake light (FIG. 6 ). The brake pressure shows in the course of greater fluctuations and below at time t ₂₀ for the first time the switch-off threshold S _Off for deactivation of the brake light. According to the illustrated embodiment, however, the brake light is not directly deactivated by the undershooting of the switch-off threshold S _Aus- the brake light remains switched on and a counter with the predetermined follow-up time T _{follow-up is} activated at time t ₂₀ . Within the follow-up time T _caster , the brake pressure continues to be monitored. Since, in the illustrated embodiment, the brake pressure before the end of the follow-up time T _caster at time t ₄₀ , already exceeds the off threshold S _Aus again at time t ₃₀ , the brake light remains active and the time counter is reset again at this time, so that when falling below the Off threshold the process can be repeated. Alternatively, instead of the switch-off threshold S _Off , another pressure threshold - for example the switch-on threshold S _{Ein can be} monitored and defined as a prerequisite for a "further activation" of the brake light. In the illustrated embodiment, the vehicle comes at time t ₅₀ to a standstill. From this point on there is advantageously an automatic construction of a brake pressure reserve up to a predetermined brake pressure p _res , which is then maintained until the next restarting operation. When the holding brake pressure p _res is reached, the brake light is deactivated. Alternatively, the brake light (contrary to the shutdown at time t ₆₀ in _FIG 6 ) remain switched on and deactivated only at a later time - after expiration of a waiting period or after detection of entering the rear space of the vehicle other vehicle or the like.

In the event that an acceleration takes place from the deceleration (that is, immediately after an aborted deceleration phase), the brake light may not however, as described above on the basis of 4 - 6 described, for the duration of the follow-up time T _lag remain switched on - although the switch-off threshold S _{out was} undershot and at the same time an acceleration process has occurred. This special case is based on the 7 - 9 explained. Parallel to monitoring the brake pressure p for undershooting or exceeding predetermined brake pressure threshold values, the vehicle deceleration a is monitored for at least one predetermined deceleration threshold value a1. In the event that the vehicle accelerates out of a deceleration phase (in which the brake pressure is automatically increased at time t ₀₀₀ and the switch-on threshold S _Ein for switching on the brake light is reached at time t ₁₀₀ ), the automatically established brake pressure p is reduced and inevitably falls below the predetermined switch-off threshold S _Off . At this time (t ₂₀₀ ), analogously to the case described above ( 4 - 6 ) a counter with the duration of the follow-up time ^T follow-up activated and the brake pressure p monitored accordingly. In parallel, the vehicle deceleration a is monitored. In the exemplary embodiment illustrated, the value of the vehicle deceleration a (in terms of absolute or absolute value) falls below the predetermined deceleration limit value a1 (| a | <| a1 |) at the time t _a1 . With falling below the delay limit a1 is a second (Time) counter started whose predetermined period of time ( _delay time T _delay ) is shorter than the follow-up time T _{caster of} the first counter. In the event that the vehicle deceleration a is still smaller (or less than or equal to) the predetermined deceleration limit value a1 within the _delay time T _delay (reaching the point in time (t ₄₀₀ )), the brake light is also switched off before the trailing time ^{T has} elapsed (FIG. with shortened follow-up time (T _caster ')) is deactivated so that there is no discrepancy between a vehicle accelerating out of an automatic deceleration process and its brake light display.

Additionally or alternatively to monitoring the deceleration threshold a1, the sign of the delay signal a can also be observed so that when there is a sign change in the delay signal due to a very strong acceleration a deactivation of the Brake lights takes place.

Furthermore, within the _{delay time} T _delay , a further (lower magnitude) delay limit value (with the same sign) can be monitored, so that when the further delay limit value is exceeded before the _{delay time} T delay has elapsed, deactivation of the brake lights can take place.

By the embodiments and measures described above is a fast and situation-appropriate control of the brake lights ensured. The second time counter on the one hand ensures that pulse-like signal peaks in the delay signal not too early Switch off the brake light, while making sure that on one of the automatic delay out (automatically or manually) initiated acceleration process too long activation of the brake lights is prevented.

By The invention becomes a reliable brake light control for lower Speed ranges created. Especially with automatic Braking, the above Driver assistance systems such as cruise control, distance-controlled cruise control, automated stop & go operation, but also in automated emergency braking systems or the like Be triggered, a reliable flicker-free until the vehicle stops Brake light control ensured.

Claims (21)

Device for brake light control in a motor vehicle with a trained for a foreign power actuation brake system, comprising - a control device for controlling the vehicle brakes, such that depending on vehicle operating conditions, an automatic braking operation is feasible, and - at least one controllable via the control unit or via a separate control device brake light , characterized in that - the control device or the control device is designed such that switching on the brake light during an automatic braking operation, below a predetermined limit speed, depending on a determined in the activated vehicle brake pressure or in dependence on a correlated with the brake pressure magnitude he follows. Device according to claim 1, characterized in that that the controller or the control device is designed such that the limit speed is designed to be administered, in particular depending from the vehicle speed and / or the vehicle inclination angle changeable around the vehicle transverse axis is. Device according to one of the preceding claims, characterized in that the control device or the control device is formed such that switching on the brake light during a automatic braking, above the predetermined limit speed, dependent on from the determined vehicle deceleration he follows. Device according to one of the preceding claims, characterized in that the control device or the control device is formed such that switching off the brake light during a automatic braking, below a predetermined limit speed, dependent on from a brake pressure determined in the activated vehicle brake or depending from a correlated with the brake pressure size. Device according to one of the preceding claims, characterized in that the control device or the control device is formed such that the at least one brake light at Reaching or exceeding a predetermined turn-on brake pressure threshold is turned on. Device according to one of the preceding claims, characterized in that the control device or the control device is formed such that the at least one brake light at Reaching or falling below a predetermined, in particular one compared to the turn-on brake pressure threshold or lower, shutdown brake pressure threshold is turned off. Device according to one of the preceding claims 5 or 6, characterized in that the control device or the control device is formed such that the predetermined switch-on brake pressure threshold and / or switch-off brake pressure threshold in dependence from the vehicle speed and / or depending on the angle of inclination Applicable to the vehicle transverse axis and / or the vehicle weight is. Device according to one of the preceding claims, characterized in that the control device or the control device is formed such that turning on the at least one brake light takes place only when the switch-on conditions over a predetermined Duration uninterrupted. Device according to one of the preceding claims, characterized in that the control device or the control device is formed such that turning off the at least one brake light occurs only when the predetermined criteria for a shutdown for one abut predetermined period of time uninterrupted. Device according to one of the preceding claims 1-9, characterized in that the control device or the control device is designed such that for the case that the vehicle after an automatic braking comes to a standstill, the at least one brake light, in particular the so-called third brake light, switched on for the duration of the service life remains. Device according to one of the preceding claims 1-9, characterized in that the control device or the control device is designed such that for the case that the vehicle after an automatic braking comes to a standstill, the at least one brake light, in particular the so-called third brake light, for a predetermined duration Switch-on time remains switched on and after expiry of the switch-on time is automatically turned off. Device according to one of the preceding claims 1-9, characterized in that the control device or the control device with a vehicle rearview monitoring device coupled and is designed such that in the event that the vehicle comes to a standstill after an automatic braking, the at least one brake light, in particular the so-called third Stop lamp automatically turns off when passing through the vehicle rear space monitoring device one in the vehicle rear space entering vehicle is detected. Device according to one of the preceding claims 10-12, characterized in that the control device or the control device is coupled with a navigation system and the elimination of the at least one brake light depending on the current one Environment type, especially depending on whether the current Environment is an inner city environment or an out of town environment. Device according to the preceding claim 13, characterized characterized in that the shutdown of the at least one brake light in dependence of the currently used road type takes place, in particular depending of whether the current street a local road, a country road or a highway. Device according to one of the preceding claims, characterized in that the control device or the control device is formed such that in an automatic braking process with a vehicle deceleration bigger or equal to a predetermined limit vehicle deceleration or with a brake pressure greater or equal to a predetermined limit brake pressure in addition to the at least one Stop lamp, the hazard warning light system is switched on. Device according to one of the preceding claims by a pressure sensor for detecting, in the activated vehicle brake prevailing, brake pressure. Device according to one of the preceding claims, characterized in that the control device or the control device is formed such that in the activated vehicle brake prevailing pressure over a calculation model is determined. Device according to one of the preceding claims, characterized in that the control device or the control device with a vehicle rearview monitoring device coupled and is designed such that in the case of a nourishing Vehicle, which is at a speed above a predetermined limit speed moves in the vehicle rear space, a changeover the brake light is at a second brake light level, the second Brake light level is characterized in particular by the fact that the Brightness of the activated brake lights are increased and / or the illuminated area of the Brake lights are increased and / or additional Brake lights are activated and / or the hazard warning lights activated become. Device according to one of the preceding claims, characterized in that the control device or the control device is designed in this way is that, in the event that the vehicle during a deceleration process initiated by an automatic braking operation, in which the brake pressure to below the shutdown threshold (S _Aus ) degraded and within a predetermined follow-up time (T _caster ) from falling below the shutdown threshold (S _Off ) again is constructed and the Abschaltschwelle (S _Aus ) again exceeds, no immediate shutdown of the brake light falls below the Abschaltschwelle (S _Aus ) takes place, and in the event that within the predetermined follow-up time (T _follower ), the Abschaltschwelle (S _Aus ) not exceeded again is turned off, the brake light. Device according to one of the preceding claims, characterized in that the control device or the control device is formed such that the vehicle on the initiation of a to the delay process subsequent Acceleration process monitored out is, and at detected vehicle acceleration, a shutdown the brake light takes place. Device according to one of the preceding claims 19-20, characterized in that the control device or the control device is designed such that the vehicle deceleration (a) is monitored, and that triggered by reaching or falling below a predetermined lower vehicle deceleration limit (a1) is monitored, whether within a _{delay time} (T _delay ) which is shorter than the follow-up time (T _follow-up ), - the vehicle deceleration is still less than or equal to the lower vehicle deceleration (a1), and in the event that the vehicle deceleration (a) for the Duration of the _{delay time} (T _delay ) is less than or equal to the lower vehicle deceleration limit (a1), the brake light is switched off, or - the vehicle deceleration (a) falls below a second predetermined vehicle deceleration limit, which in absolute terms is less than the first vehicle deceleration limit (a1), and in the event that the vehicle deceleration (a) w During the delay time (T _delay) falls below the second vehicle deceleration boundary, the brake light is switched off, or - the signal of the vehicle deceleration is monitored for a change of sign out and for the case that during the delay time (T _delay), a sign change is detected, the brake light is switched off.