DE10144846B4 - Headlamp unit for vehicles with cornering light function and method for controlling such a headlamp unit - Google Patents

Abstract

A headlamp unit for vehicles (2) having a headlamp (1) with a light source, the emitted light in a light exit direction (3), wherein the light exit direction (3) by means of a control unit (4) for a cornering light function in a horizontal plane around a Pivoting angle (α) is pivotable, wherein the control unit (4) is coupled to a detector (5) for direct and / or indirect detection of moisture, characterized in that the pivoting angle (α) in the horizontal plane in response to a signal of Detector (5) is controllable such that the swivel angle (α) is reduced at Fahrbahnnässe compared to a setting on dry roads.

Description

The present invention relates to a headlamp unit for vehicles which has a headlamp with a light source, the emitted light emerges in a light exit direction, wherein the light exit direction by means of a control unit for a cornering function in a horizontal plane is pivotable about a pivot angle, wherein the control unit ( 4 ) with a detector ( 5 ) is coupled for direct and / or indirect detection of moisture. In addition, the invention relates to a method for controlling a vehicle headlamp unit with a light source, the light exit direction for a cornering light function in a horizontal plane is pivotable about a pivot angle.

In the case of conventional headlight units that can only be adapted to a limited extent to the driving situation, different light functions can be generated by controlling individual light sources of the headlight unit. These light functions essentially comprise a dipped beam, a high beam and u. U. also a fog light. With such a known headlamp unit, the illumination of the environment can be adapted only very limited to different driving situations and weather conditions. In addition, an automatic adaptation to certain driving situations has not been realized.

For this reason, there is the desire to introduce new headlamp systems, with which light functions can be realized, the light distribution is more variable and can be better adapted to driving and environmental conditions. Such adaptive headlamp systems are currently being developed within the framework of the so-called AFS project (Advanced Frontlighting System) by vehicle manufacturers and the supplier industry. With the headlamp units of this system, light distributions for different driving situations can be generated. Among other things, it is possible to pivot during cornering the light exit direction in a horizontal plane and thus to provide a cornering light function. In addition, in a so-called bad weather light, the illuminance is reduced or hidden directly in front of the vehicle in order to reduce reflections on wet roads, which lead to dazzling oncoming traffic. It has been shown that just such changes of the conventional low beam when cornering and in the wet can contribute to a significant improvement in lighting conditions and driving safety in the dark.

A disadvantage of the pivoting of the light exit direction for the cornering light function, especially in left turns for right-hand traffic, is the stronger glare of oncoming traffic. In addition, in conventional adaptive headlight units despite the bad weather light function on wet roads the glare of oncoming traffic is still too strong. At such ratios, the luminance coefficient for the forward reflection increases while the luminance coefficient for the backward reflection decreases. This change in the optical properties of wet roads leads to an increased glare impairment of other road users, which could not be sufficiently eliminated by the previous adaptive headlight units.

In the DE 199 14 412 A1 a headlight for vehicles is described with two reflector areas arranged one above the other, of which at least the lower reflector area is pivotable for generating a cornering light. Furthermore, a headlight system with at least two such headlights is described, the pivot angle can be optionally controlled independently. About a humidity sensor or a rain sensor, the road surface wetness can be detected and taken into account in the pivoting of the headlights such that the respective lower reflector areas of the two headlights are pivoted outwards, thereby less illuminate the near area in front of the vehicle and thus dazzling the Reduce oncoming traffic on wet roads.

In the DE 199 22 735 A1 Finally, a vehicle lighting system is described in which the vehicle lights are controlled in response to various weather and road conditions. In particular, it will be described how a state of increased road wetness can be effectively detected.

It is the object of the present invention to provide a headlamp unit and a method for controlling a vehicle headlamp unit of the type mentioned in which when cornering the best possible illumination of the road can be achieved, but at the same time the least possible dazzling oncoming traffic, especially at Wetness, occurs.

According to the invention, this object is achieved by a headlamp unit having the features of claim 1 and a method for controlling a vehicle headlamp unit having the features of claim 9. Advantageous embodiments of this headlamp unit and this method will become apparent from the dependent claims.

The headlight according to the invention is characterized in that the pivoting angle in the horizontal plane in response to a signal of the detector, hereinafter referred to as Wetness detector is called, is controllable such that the swivel angle is reduced in road conditions compared to a setting in dry conditions.

In studies of adaptive headlamp units has been found that arise with respect to the glare of oncoming traffic in the cornering light function particularly strong differences between dry ambient conditions and environmental conditions with wet or damp track. In the headlamp unit according to the invention, the occurrence of moisture is detected and the swivel angle of the light exit direction in the cornering light function is controlled as a function of the occurrence of moisture. The headlamp unit according to the invention can thus react very flexibly and automatically to the changed conditions when wet occurs. In particular, the increased glare of oncoming traffic in the event of moisture can be taken into account by reducing the swivel angle.

The wetness detector of the headlamp unit according to the invention can detect the actuation and / or the wiping frequency of a windshield wiper and transmit the detected signal to the control unit for controlling the swivel angle of the cornering light. This indirect detection of the occurrence of moisture has the advantage that existing facilities of a vehicle can be used. The wetness detector thus makes the information associated with the operation of the windshield wiper or its wiping frequency usable for the cornering light function of the headlamp according to the invention. Such a coupling can be realized very inexpensively. Advantageously, the wetness detector transmits to the control unit only a signal for controlling the pivoting angle when a certain wiping frequency is exceeded or when the windshield wiper has exceeded a certain minimum operating time to a wrong change in the cornering function, eg. B. during a window cleaning, exclude.

The wetness detector may also be a rain sensor, the z. B. wetness detected on a vehicle window. This embodiment is particularly advantageous when a rain sensor is already provided for the windshield wiper function. In addition, a wetness detector can be provided which directly detects the reflective properties of the roadway. Such detection can, for. B. optically. With such a wetness detector advantageously the reflection properties of the road and the associated dazzling effect for oncoming traffic can be detected particularly accurately. However, the realization of such a detector is relatively complicated and expensive.

The control unit of the headlamp unit according to the invention is advantageously coupled to a cornering detector and the swivel angle is further controllable in response to a signal of this cornering detector. The control of the swivel angle thus takes place as a function of the occurrence of moisture and the driven curve radius. In this way, on the one hand, the illumination of the road can be optimized and on the other hand, the glare of oncoming traffic, especially on wet roads, can be reduced to an acceptable level.

According to an advantageous embodiment of the headlamp, the swivel angle is limited, wherein the maximum swivel angle is in a range between 12 ° and 20 °, wherein an angle of 0 ° corresponds to a non-pivoted state. Advantageously, the maximum pivot angle is in a range between 15 ° and 19 °, and particularly preferred is a maximum pivot angle of 18 °. It has been found that such a limitation of the swivel angle represents an ideal compromise between a good illumination of curves, as they usually occur, and the reduction of glare oncoming traffic. Larger swivel angles would only be possible with very small curve radii, i. H. required at very strong curvature of the curves. Such curves are very rare in actual road progressions. It has been found that with a limitation of the swivel angle to ± 18 ° almost all actually occurring curves are optimally illuminated and at the same time an excessive glare of the oncoming traffic is avoided by a limitation to this maximum angle.

The inventive method for controlling a vehicle headlamp unit with a light source, the light exit direction for a cornering light function in a horizontal plane is pivotable about a pivot angle, characterized in that the pivot angle of the light exit direction is controlled in dependence on the road surface wetness such that the pivot angle at Lane wetness is reduced compared to a setting on dry roads. As explained above, with such control of the cornering light function of an adaptive headlamp unit, it is possible to respond very flexibly and automatically to the occurrence of wetness and the associated altered glare effects of the headlamp for oncoming traffic.

The road surface wetness can be detected indirectly via the actuation and / or the wiping frequency of a windshield wiper, via a rain sensor or directly via the reflective properties of the roadway.

On wet roads results due to the changed reflective properties of the roadway, a greater glare of oncoming traffic. In addition, especially in right-hand traffic in left turns, the pivoting of the light exit direction in the direction of the driven curve leads to a stronger glare of oncoming traffic. The inventive reduction of the swivel angle can take these two factors into account in order to reduce the glare of oncoming traffic.

In addition, the occurrence of road wetness, the maximum swing angle can be reduced. A value in the range between 12 ° and 20 ° has proven to be advantageous, with an angle of 0 ° corresponding to the untwisted state. Particularly advantageous is a limitation of the maximum pivot angle to 18 °. By this measure extreme Verschwenkungen, especially at particularly small curve radii can be prevented, since a particularly strong glare of oncoming traffic occurs here.

According to a further refinement of the method according to the invention, it is detected whether a right-hand or left-hand bend is being driven, wherein the swivel angle controlled in the case of a left-hand bend differs from the swivel angle actuated in the case of a right-hand turn. Of course, this results in different settings for right- or left-hand traffic. This measure takes into account the different glare effects of the curve light function as a function of a left-hand or a right-hand curve. In right-hand traffic, in a left-hander turn, the cornering light function leads to a greater glare of oncoming traffic than in the case of a right-hander turn. In a right turn, increased glare occurs only at very large distances, whereas at small distances the glare is reduced.

According to a further embodiment of the invention, the adjustment of the pivot angle also takes place depending on whether the headlamp unit has a bad weather light function or not. If no bad weather light function is switched on in the wet, the swivel angle can be reduced more strongly than when the bad weather light is switched on. Furthermore, the limitation of the maximum achievable swivel angle depending on whether a bad weather light function is turned on or not. For example, a limitation of the maximum pivot angle can only be done when a bad weather light is not turned on. In addition, the limit may be lower when switched on bad weather light, as in bad weather light not switched on.

In the following, investigations that have led to the headlight unit according to the invention and the method according to the invention, as well as an embodiment of the invention with reference to the drawings will be described.

1 schematically shows the geometric relationships of the cornering light function,

2 shows schematically an embodiment of the headlamp unit according to the invention,

3 shows measurements of the illuminance E for an oncoming driver in a left turn in a dry lane as a function of the distance of the vehicles for different pivoting angles,

4 shows measurements like in 3 for wet road conditions with puddles,

5 shows measurements like in 3 for a right turn in wet conditions with puddles and

6 shows measurements of the exposure H at the meeting of two vehicles in a right and a left turn for different swivel angles in wet, damp and dry roads with and without activated bad weather light function.

For the present invention, measurements of the illuminance E which occurs in an adaptive headlamp unit with cornering light function at the location of a driver of an oncoming vehicle were performed. The illuminance sensor was mounted in a vehicle equipped for left-hand traffic at the position of the eyes of a driver in right-hand traffic at a height of 1.13 m. On this observation vehicle, a vehicle equipped with the adaptive headlamp was moved on a constant radius curve R = 100 m at a constant speed. The relative position s of this vehicle and the illuminance E of the observation vehicle were recorded. When presented in the 3 . 4 and 5 is the position s of the observation vehicle at s = 156 m. From the measured curves, the illuminance E results at a specific relative position s of the two vehicles under different conditions.

In 1 it is shown how the swivel angle α is defined. A vehicle 2 moves along the right lane of a road 7 , The magnitude of the curvature of a roadway curve is indicated by the radius of curvature R. The smaller the radius of curvature R, the more the roadway is curved. When cornering, the light exit direction 3 of the light source of the headlight 1 emitted light by an angle α pivoted to provide a cornering function. The angle α indicates the angle of the pivoting with respect to the untwisted light emission to the front.

3 shows measurements of illuminance E for an oncoming driver in a left turn for a vehicle, in which the light exit direction has been pivoted by an angle α in the direction of the curve. The radius of curvature was R = -100 m. In addition, for comparison, the illuminance E has been measured at undelivered light emission on a straight road. The roadway was at the in 3 shown measurements dry. It turns out that a greater pivoting of the light exit direction into the curve leads to a higher illuminance for an oncoming driver. Nevertheless, in the case of the cornering light function, the illuminance is lower for distances> 30 m, ie for s <126 m, than in conventional headlight systems without cornering function on straight roads. A certain proportion of these illuminances is caused by the reflection of the headlight light on the road surface to the oncoming driver. These reflective properties are strongest along the axis between the headlamp and the eye of the observer for both dry and wet or wet road surfaces. Obviously, the contribution of the reflected light to the glare effect increases with the swivel angle of the light exit direction in the curve.

In 4 Measurements are shown that were made in wet conditions with puddles on the road. The same procedure was used as in the 3 applied measurements shown. It shows a significant increase in the level of illumination of the driver of an oncoming vehicle. In addition, it can be seen that the illuminance levels in the cornering light function are not significantly higher for distances> 30 m than for conventional straight-line headlight units without cornering function. In 4 the dotted lines also show measurements with the bad weather function switched on. In the case of bad weather lighting is reduced directly in front of the vehicle, whereby the indirect glare of the oncoming driver is reduced by reflection of the emitted light in the area directly in front of the vehicle.

In 5 Measurements in wet road conditions with puddles on the road are shown 4 However, from the perspective of the vehicle with the cornering light function, a right turn was driven. This results in the opposite effect for the cornering light. The farther the light exit direction is turned into the curve, the farther the maximum illuminance of the headlamp, as perceived by an oncoming vehicle, is shifted to greater distances. At the same time, this leads to a reduction of the illuminance E for smaller distances between the vehicles at s> 125 m in comparison to an untwisted light exit direction.

In 6 are the results of in the 3 . 4 and 5 summarized measurements again. Shown is the measured exposure H in the encounter process of two vehicles for different swivel angle α of the light exit direction of the headlights of a headlamp in wet and dry lanes with activated bad weather light and without activated bad weather light. The direction of the curve is given from the perspective of the vehicle with the headlight with cornering light function. The exposure H results as follows:

In summary, the measurements clearly show that when wet, ie wet or damp, the illuminance at the driver's seat of an oncoming vehicle significantly increases when the light exit direction of a headlamp is tilted in the direction of the curve, resulting in dazzling oncoming drivers. According to the invention, therefore, for a headlamp unit with cornering light function, a wetness detector 5 proposed that directly or indirectly detects the occurrence of moisture, especially on the road, and whose signals are taken into account in the control of the cornering light function. 2 shows such a headlamp unit.

The headlight unit comprises a headlight 1 with a light source whose light emission directed by suitable means in the light exit direction 3 is emitted. At the headlight 1 it can be a projection headlamp or a reflection headlamp. The light source may be, for example, a gas discharge lamp. Besides, it can be at the headlight 1 to act a light guide headlamp, in which the light emitted by a light source is coupled into a light guide, is transmitted by the latter to a suitable location of the vehicle and is coupled there via light output elements.

For providing the cornering light function, the light exit direction is the light source of the headlamp 1 pivotable in an horizontal plane by an angle α. This pivoting can either by pivoting the headlamp 1 can be achieved in total or by pivoting light extraction elements.

The headlight 1 This embodiment is designed so that the pivoting of the light exit direction is limited to a certain maximum pivot angle. Investigations of typical road courses and the glare effects with turned-on headlights have shown that a maximum swivel angle in a range between 12 ° and 20 ° is advantageous. In this case, a range between 15 ° and 19 ° is preferred and a maximum swing angle of 18 ° is most preferred.

The swivel angle α of the headlamp unit is via a control unit 4 controllable. For example, the control unit operates 4 a stepper motor, the headlight 1 pivoted. The control unit 4 Signals are transmitted by two detectors. On the one hand is a cornering detector 6 provided, which determines the radius of the currently driven curve. The cornering detector 6 can record, for example, the steering angle of the steering wheel or the position of the front wheels. A signal indicative of the radius of the driven curve is taken by the cornering detector 6 transmitted to the control unit. The size of this signal flows into the control of the swivel angle α by the control unit 4 one. The swivel angle α is thus controlled in dependence on the signal of the cornering detector. Here, the pivot angle α is greater, the smaller the radius of the driven curve. The relationship between these two quantities may be linear, but there may be another nonlinear relationship.

There is also a detector 5 intended for direct or indirect detection of moisture. In the simplest case, the condition of a wet roadway is detected by detecting the windshield wiper frequency. If a certain windshield wiper frequency is exceeded, the wetness detector transmits 5 the control unit 4 a corresponding signal. Advantageously, this signal is transmitted only after a minimum operating time of the windshield wiper to prevent a false detection of moisture, eg. B. during a window cleaning, exclude. In addition, the wetness detector can 5 be coupled with a rain sensor provided for the windshield wiper. Furthermore, it is possible, the degree of wetness of the roadway directly on the reflective properties of the road, z. B. by means of an optical sensor to determine. The occurrence of moisture and possibly the degree of wetness of the road surface is determined by the wetness detector 5 to the control unit 4 transfer. This signal also flows into the control of the swivel angle α. The control unit 4 can realize the following control options for the swivel angle α:
When wet or when exceeding a certain degree of wetness, the cornering function of the headlamp unit can be completely disabled, ie the swivel angle is set to α = 0 °. Further, the functional relationship between the swivel angle α and the radius of the driven curve can be changed so that for a given radius of curvature in the wet a smaller swivel angle α is set as in drought. In addition, the degree of reduction of the roadway can be included in the degree of reduction. In addition, in the detection of road surface wetness, the maximum achievable swivel angle can be limited or a reduction of this maximum swivel angle can be set compared to the maximum swivel angle when the road surface is dry. For example, the maximum swivel angle can be limited to a value in the range between 0 ° and 20 °, advantageously to a value between 15 and 19 ° and particularly preferably to a value of 18 °.

Otherwise, the cornering detector 6 Also detect whether a right or left turn is driven and depending on whether the vehicle is equipped for right- or left-hand traffic, the change in the swing angle may also depend on whether a right or left turn is driven. Advantageously, the influence of a wet or wet roadway will lead to a greater reduction of the swivel angle α when a left-hand bend (in the case of right-hand traffic) is driven.

Claims (15)

Headlamp unit for vehicles ( 2 ), which has a headlight ( 1 ) having a light source, the emitted light in a light exit direction ( 3 ), wherein the light exit direction ( 3 ) by means of a control unit ( 4 ) is pivotable about a pivoting angle (α) for a cornering light function in a horizontal plane, wherein the control unit ( 4 ) with a detector ( 5 ) is coupled to the direct and / or indirect detection of moisture, characterized in that the pivot angle (α) in the horizontal plane in response to a signal of the detector ( 5 ) is controllable such that the swivel angle (α) is reduced at Fahrbahnnässe compared to a setting on dry roads. Headlamp unit according to claim 1, characterized in that the detector ( 5 ) detects an actuation and / or wiping frequency of a windshield wiper and the detected signal to the Control unit ( 4 ) for controlling the swivel angle (α). Headlamp unit according to claim 1, characterized in that the detector ( 5 ) is a rain sensor that detects moisture on a vehicle window. Headlamp unit according to claim 1, characterized in that the detector ( 5 ) Reflection properties of the roadway detected directly. Headlamp unit according to one of the preceding claims, characterized in that the control unit ( 4 ) with a cornering detector ( 6 ) and the swivel angle (α) is further dependent on a signal of the cornering detector ( 6 ) is controllable. Headlamp unit according to one of the preceding claims, characterized in that the pivoting angle (α) is limited and that a maximum pivoting angle is in a range between 12 ° and 20 °, wherein an angle of 0 ° corresponds to a non-pivoted state. Headlamp unit according to claim 6, characterized in that the maximum pivot angle is in a range between 15 ° and 19 °. Headlamp unit according to claim 7, characterized in that the maximum pivot angle is 18 °. Method for controlling a vehicle headlamp unit with a light source whose light exit direction for a cornering function in a horizontal plane is pivotable about a pivot angle (α), characterized in that the pivot angle (α) in the horizontal plane of the light exit direction in dependence on the road surface wetness such is controlled that the swivel angle (α) is reduced in wet conditions compared to a setting on dry roads. A method according to claim 9, characterized in that the road surface wetness is detected indirectly via an actuation and / or a wiping frequency of a windshield wiper or a rain sensor. A method according to claim 9, characterized in that the road wetness is detected directly on reflection properties of the road. Method according to one of claims 9 to 11, characterized in that the occurrence of road wetness, a maximum pivot angle is reduced. Method according to one of claims 9 to 12, characterized in that a maximum pivot angle is limited to a value in the range between 12 ° and 20 °, wherein an angle of 0 ° corresponds to a non-pivoted state. A method according to claim 13, characterized in that the maximum pivoting angle is limited to a value of 18 °. Method according to one of claims 9 to 14, characterized in that it is detected whether a right or left turn is driven and that the driven at a left turn angle (α) from the controlled in a right turn swing angle (α) is different.

Images