Electric lamp and discharge devices: systems – Special application – Vehicle
Reexamination Certificate
2001-02-09
2003-02-11
Vu, David (Department: 2821)
Electric lamp and discharge devices: systems
Special application
Vehicle
C315S083000, C307S010800
Reexamination Certificate
active
06518704
ABSTRACT:
BACKGROUND
The invention pertains to methods and devices for automatically switching on or off the lights of a vehicle.
In order to improve the safety and comfort of motor vehicles, many functions have been automated, thereby unburdening the driver. In one known method, the lights of the vehicle are automatically switched on and off as a function of brightness. Two light sensors are used: the first determines the brightness of the vehicle surroundings and switches on the lights of the vehicle as soon as the ambient brightness falls below a predetermined minimum brightness level. The second light sensor determines only the brightness in the driving direction and thus is able to determine whether the vehicle approaches a tunnel opening, e.g., in which case the second light sensor switches on the lights of the vehicle even though the ambient if brightness still exceeds the aforementioned minimum brightness level until the vehicle enters the tunnel. One disadvantage of this method is that short, dark sections are not recognized as such, so that the lights of the vehicle frequently switch on and then off again shortly thereafter, as is the case, for example, when driving beneath a bridge that spans the road. Drivers coming from the opposite direction may become annoyed; in any case, the service life of the gas discharge lamps is significantly reduced by these frequent switching processes.
SUMMARY
The present invention is based on the object of making available a method and device, by which means the lights of a vehicle are reliably switched on if the ambient brightness is too low or if the vehicle enters a tunnel. Moreover, the lights of the vehicle are prevented from switching on and then off again a short time later when driving through short, dark sections.
According to the invention, this objective is realized with a method in which
the driving speed is determined,
the mean brightness H
1
within a first cone that lies in front of the vehicle, looking into the driving direction, is determined, where the first cone has a large cone angle, and where the tip of the cone lies inside the vehicle,
the mean brightness H
2
within a second cone that lies in front of the vehicle, looking into the driving direction, is determined, where the cone angle of the second cone is smaller than that of the first cone, and where the tip of the second cone lies inside the vehicle,
the mean brightness H
3
within a third cone that lies in front of the vehicle, looking into the driving direction, is determined, where the cone angle of the third cone is smaller than that of the first cone, the tip of the third cone lies inside the vehicle, where the longitudinal axis of the third cone is elevated in the driving direction relative to the longitudinal axis of the second cone, as viewed from the side, and where the envelope of the third cone that lies outside its tip is located within the envelope of the first cone,
the lights of the vehicle are switched on if
the driving speed is greater than zero, and the brightness values H
1
, H
2
and H
3
fall below a minimum value H
min,1
over a driving distance S
1
or
the driving speed is greater than zero, and the brightness value H
2
is less than the brightness value H
1
by an amount &Dgr;H
min,1
and the brightness value H
3
is greater than the brightness value H
2
by less than an amount &Dgr;H
min,2
over a driving distance S
1
or
the driving speed is equal to zero, the ignition is switched on and the brightness values H
1
, H
2
and H
3
fall below a minimum value H
min,1
during a time interval &Dgr;T
min,1
, and
the lights of the vehicle are switched off if
the driving speed is greater than zero and the brightness values H
1
, H
2
and H
3
exceed a minimum value H
min,2
over a driving distance S
1
or
the driving speed is equal to zero, the ignition is switched on and the brightness values H
1
, H
2
and H
3
exceed a minimum value H
min,2
during a time interval &Dgr;T
min,2
.
The method according to the invention provides the advantage that the brightness ahead of the vehicle is also determined by the third light sensor oriented, when viewed from the side, at an inclination relative to the longitudinal axis of the second cone. The evaluation of this additional information in accordance with the proposed method makes it possible to differentiate, for example, the ceiling of a tunnel from the underside of a bridge that passes over a road. In the method according to the invention, the lights of the vehicle are switched on before the vehicle enters the tunnel, with the lights of the vehicle remaining switched off if the vehicle drives beneath a bridge that passes over a road. Since the driving distance S
1
forms part of the switch-on and the switch-off condition, the speed of the vehicle is also taken into consideration. The method according to the invention also provides the advantage that the lights of the vehicle are only switched off if the brightness remains above a predetermined minimum level for a sufficient period of time.
According to the invention, the objective of the invention is also realized with a method in which
the driving speed is determined,
the mean brightness H
1
within a first cone that lies in front of the vehicle, looking into the driving direction, is determined, where the first cone has a large cone angle, and where the tip of the cone lies inside the vehicle,
the mean brightness H
2
within a second cone that lies in front of the vehicle, looking into the driving direction, is determined, where the cone angle of the second cone is smaller than that of the first cone, and where the tip of the second cone lies inside the vehicle,
the mean brightness H
3
within a third cone that lies in front of the vehicle, looking into the driving direction, is determined, where the cone angle of the third cone is smaller than that of the first cone, where the tip of the third cone lies inside the vehicle, where the longitudinal axis of the third cone is elevated in the driving direction relative to the longitudinal axis of the second cone, as viewed from the side, and where the envelope of the third cone that lies outside its tip is located within the envelope of the first cone,
the lights of the vehicle are switched on if
the driving speed is greater than zero, and the mean values of the brightness values H
1
, H
2
and H
3
fall below a minimum value H
min,1
over a driving distance S
1
or
the driving speed is greater than zero, and the mean value of the brightness value H
2
is less than the mean value of the brightness value H
1
by an amount &Dgr;H
min,1
and the mean value of the brightness value H
3
is greater than the mean value of the brightness value H
2
by less than an amount &Dgr;H
min,2
over a driving distance S
1
or
the driving speed is equal to zero, the ignition is switched on and the mean values of the brightness values H
1
, H
2
and H
3
fall below a minimum value H
min,1
during a time interval &Dgr;T
min,1
, and
the lights of the vehicle are switched off if
the driving speed is greater than zero and the mean values of the brightness values H
1
, H
2
and H
3
exceed a minimum value H
min,2
over a driving distance S
1
or
the driving speed is equal to zero, the ignition is switched on and the mean values of the brightness values H
1
, H
2
and H
3
exceed a minimum value H
min,2
during a time interval &Dgr;T
min,2
.
This method provides the advantage that brief fluctuations of one or more brightness values do not cause the lights of the vehicle to be unnecessarily switched on and off. The speed of the vehicle is also taken into consideration by determining mean values while traveling a distance S
1
.
According to one variation of the method,
the driving speed is determined,
the mean brightness H
1
within a first cone that lies in front of the vehicle, looking into the driving direction, is determined, where the first cone has a large cone angle, and the tip of the cone lies inside the vehicle,
the mean brightness H
2
within a second cone that lies in front of the vehicle, looking into the driving direction,
Lewis J. Gordan
Valeo Auto-Electric Wischer und Motoren GmbH
Vu David
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