Method and device for detecting rain on a windshield

• US 9,322,952 B2
• Filed: 12/12/2012
• Issued: 04/26/2016
• Est. Priority Date: 12/12/2011
• Status: Active Grant

• Current Assignee: Hella KGaA Hueck & Company
• Original Assignee: Hella KGaA Hueck & Company
• Inventors: Niemann, Thomas, Ldtke, Olaf, Schlarmann, Almut, Palloks, Jrgen, Czsich, Cevin, Strmann, Jrg
• Primary Examiner(s): WILLIAMS, HEZRON
• Assistant Examiner(s): Phan, Truong
• Application Number:
  US13/712,058
• Publication Number:
  US 20130145839A1
• Time in Patent Office: 1,231 Days
• Field of Search: 735/79, 735/97, 735/98, 736/45, 736/46
• US Class Current: 1/1
• CPC Class Codes: B60S 1/0491 Additional elements being fixed on wipers or parts of wipers not otherwise provided for, e.g. covers, antennae or lights
• CPC Class Codes: B60S 1/0859 Other types of detection of rain, e.g. by measuring friction or rain drop impact
• CPC Class Codes: G01N 2291/02809 Concentration of a compound, e.g. measured by a surface mass change
• CPC Class Codes: G01N 29/2437 Piezoelectric probes
• CPC Class Codes: G01W 1/14 Rainfall or precipitation gauges measuring volume in general G01F

Abstract

In a method for detecting rain on a windshield, whose degree of wetting is determined with at least one sensor value, it is provided that the sensor value is determined piezoelectrically, wherein vibrations on the windshield are detected, which change depending on the degree of wetting or raindrops hitting the windshield. As a result, the entire windshield serves as a detection surface, thereby yielding a high accuracy.

Claims

1. A method for detecting rain on a windshield, comprising:

detecting vibrations on the windshield, caused by rain, with a piezoelectric sensor, the vibrations being detected via at least one wiper blade of a windshield wiper system, and via a coupling between the at least one wiper blade and the windshield,

determining a sensor value from the output of the piezoelectric sensor, which depends on the degree of wetting or raindrops hitting the windshield,

comparing the sensor value with known vibration profiles, and

determining the environmental condition on the windshield, caused by the rain, from said comparing;

wherein at least one additional sensor value is detected, wherein an optical signal is sent out, the optical signal is reflected on the windshield in a predetermined detection range, the reflected optical signal is detected, and a differential value is derived from the transmitted and detected signal, based upon which the degree of wetting is determined for the windshield.

2. A method for detecting rain on a windshield, whose degree of wetting is determined with at least one sensor value:

wherein the sensor value is determined piezoelectrically, wherein vibrations on the windshield are detected, which change depending on the degree of wetting or raindrops hitting the windshield, and that the vibrations on the windshield are detected via at least one wiper blade of a windshield wiper system and its coupling to the windshield;

wherein at least one additional sensor value is detected, wherein an optical signal is sent out, the optical signal is reflected on the windshield in a predetermined detection range, the reflected optical signal is detected, and a differential value is derived from the transmitted and detected signal, based upon which the degree of wetting is determined for the windshield;

wherein, when the windshield wiper system is activated for the first time, the area of the windshield in which the optical signal is reflected is wiped especially slowly, and any water located on the windshield is determined and quantified with the optical signal in the wiping process.

3. A device for detecting rain on a windshield, comprising:

a windshield wiper system of the windshield,

at least one wiper blade included in said windshield wiper system,

at least one rain sensor included in the windshield wiper system includes at least one piezo element,

the at least one wiper blade includes one of the at least one rain sensors having the at least one piezo element, with the piezo element being coupled to the windshield through the wiper blade, and

an output of the piezo element is compared to stored vibration profiles to determine the environmental condition on the windshield caused by rain;

wherein the at least one rain sensor includes at least one additional, optoelectric sensor unit.