EXTENDING HAZARD FLASHER DURATION WITH KEY OFF BY MINIMIZING CURRENT DRAW

• US 20090096601A1
• Filed: 10/15/2007
• Published: 04/16/2009
• Est. Priority Date: 10/15/2007
• Status: Active Grant

• Current Assignee: International Truck Intellectual Property Co. LLC (Volkswagen AG)
• Original Assignee: International Truck Intellectual Property Co. LLC (Volkswagen AG)
• Inventors: Gumbel, Matthew J., Bell, Joseph A.
• Granted Patent: US 7,956,732 B2
• Time in Patent Office: Days
• US Class Current: 340/471
• CPC Class Codes: B60Q 1/46 for giving flashing caution signals during drive, other than signalling change of direction, e.g. flashing the headlights or hazard lights

Abstract

A vehicle flasher hazard function is implemented on an electrical controller having control over vehicle exterior lights. The flasher hazard function features an optimized duty cycle and operational frequency, consistent with legal requirements for the flasher rate. The point in time that individual bulbs are turned on is staggered in time to avoid all bulbs being simultaneously activated. This distributes the current surges associated with bulb activation being distributed in time. When a vehicle battery can no longer sustain the legally mandated flasher rate an optional path for flasher operation at a reduced rate is provided.

Claims

1. A vehicle comprising:

a plurality of warning lights mounted to be visible on the exterior of the vehicle;

a vehicle battery for supplying electrical power to the plurality of warning lights;

a plurality of switches including at least one switch for each of the plurality of warning lights allowing each warning light to be turned on and off individually; and

a controller for the plurality of switches, the controller enabling operation of the plurality of warning lights in a hazard flashing mode where the warning lights appear to flash on and off in synchronization, the controller providing for optimizing the operating frequency and duty cycle of the warning lights.

2. A vehicle according to claim 1, wherein the optimized duty cycles of the warning lights includes staggering turning on the lights for a period not readily perceived visually.

3. A vehicle according to claim 1, further comprising:

an engine and generator combination for recharging the battery; and

the controller being responsive to the availability of instantly generated power to optimize a duty cycle and operational frequency of the warning lights in the hazard flashing mode which is calculated to extend expected warning light service life.

4. A vehicle according to claim 3, wherein cool down of the warning lights is minimized consistent with producing a visually perceptible period where the warning lights appear extinguished.

5. A vehicle according to claim 2, further comprising:

the controller providing for staggering the periods that the warning lights are on in time in the hazard flashing mode responsive to an unavailability of vehicle generated power, and the controller further provides for setting the operating frequency and the duty cycle of the warning lights to conserve charge on the battery.

6. A vehicle according to claim 2, further comprising:

the controller being further responsive to charge on the battery declining below at least a first critical threshold for reducing operating frequency of the warning lights in the hazard flashing mode as required to maintain visible flashing.

7. A vehicle according to claim 6, further comprising:

the controller being further responsive to charge on the battery declining below a lower threshold than the first critical threshold for shedding warning lights from the hazard flashing mode.

8. A vehicle according to claim 7, wherein the optimized duty cycles of the warning lights includes staggering turning on the lights for a period not readily perceived visually.

9. A vehicle according to claim 8, further comprising:

the controller being further responsive to charge on the battery declining below at least a first critical threshold for reducing operating frequency of the warning lights in the hazard flashing mode as required to maintain visible flashing.

10. A vehicle according to claim 9, further comprising:

the controller being further responsive to charge on the battery declining below a lower threshold than the first critical threshold for shedding warning lights from the hazard flashing mode.

11. A hazard warning system for a motor vehicle comprising:

a plurality of lights;

a battery for supplying power for the plurality of lights;

a control unit providing individual control over each of the plurality of lights;

the control unit providing operation of the plurality of lights in a hazard flasher mode where the lights appear to an observer to flash on and off concurrently;

the hazard flasher mode providing periods when each of the plurality of lights is on and off, the on duty cycle of the lights and the operating frequency being adjusted to conserve battery charge without interrupting hazard flasher mode operation.

12. A hazard warning system for a motor vehicle according to claim 11, the hazard warning system further comprising:

the controller providing for staggering the periods that the warning lights are on in time in the hazard flashing mode responsive to an unavailability of vehicle generated power, and the controller further provides for setting the operating frequency and the duty cycle of the warning lights to conserve charge on the battery.

13. A hazard warning system for a motor vehicle according to claim 12, the hazard warning system further comprising:

an engine and generator combination for recharging the battery.

14. A hazard warning system for a motor vehicle according to claim 13, the hazard warning system further comprising:

the control unit being responsive to the availability of instantly generated power from the engine and generator to optimize a duty cycle and operational frequency of the warning lights in the hazard flashing mode which is calculated to extend expected warning light service life.