Abstract:
A system for detecting the presence of rain droplets on a windshield employs a source of radiant energy, such as an LED, and a photodetector installed on the instrument panel of a vehicle. The LED and the photodiode are arranged with respect to one another such that light from the LED cannot reflect directly off the windshield onto the photodiode. Only when the light from the LED is back scattered by an environmental condition, such as the raindrops on the exterior of the windshield, the condensation of moisture on the interior of the windshield, or the presence of smoke in the cabin, will the photodiode receive the light from the LED. Each of these environmental conditions has a predeterminable characteristic signature that permits the processing of data to detect same. An ambient light signal is subtracted from the combination of the rain and ambient light signals by pulsed operation of the LED and subtracting the ambient light signal, which is detected when the LED is dark, from the combined LED and ambient light signal which is present when the LED is illuminated. A further LED is provided to effect a fog detection system that detects condensation on the interior of the vehicle windshield. The further LED illuminates the photodiode in a manner whereby the light on the photodiode is reduced when condensation is present. Also, a monitoring arrangement that employs a separate light sensor provides compensation for variances resulting from component aging and thermal influences.
Abstract:
An apparatus and method for controlling the operation of the windshield wipers of a vehicle in response to the deposition of water on the exterior of the windshield; the operation of the air conditioning system in response to the formation of water condensation on the interior of the windshield of the vehicle; and the operation of the ventilation system in response to the presence of smoke in the cabin of the vehicle.
Abstract:
The invention relates to a device for the automatic control of a windscreen wiper motor. The device has a moisture sensor which emits a signal depending on the moisture on the windscreen or another point on a motor vehicle so that this signal to some extent produces an analog reflection of the moisture varying in time. The output signal of the sensor is evaluated in such a way that it is continuously compared with a threshold value which can be altered. Every time this threshold value is reached or exceeded by a pulse-like change in the sensor output signal, this event is counted. After a given number Z of such events the windscreen wiper motor is switched on.
Abstract:
An optoelectronic sensor 1 for detecting foreign bodies, especially raindrops on a windshield, includes an outer housing part 2 and an inner housing part as well as a fastening device 4, which is glued to a pane 5. A fastening means, for instance comprising two slides 6, is provided, guided in the outer housing part 2, and can be made to engage the fastening device 4 for securing the sensor 1 to the pane 5. In the interior of the sensor 1, the inner housing part, which carries the optoelectronic elements of the sensor 1, is pressed toward the pane 5 with a spring force braced against the outer housing part 2, in order to accomplish the optical coupling with the pane.
Abstract:
A method for controlling a windshield wiper, particularly on a motor vehicle, in which a rain sensor is located on the windshield to be wiped in the region of the windshield wiper and gives off a sensor signal as a function of the amount of wetness. The rate of change of the sensor signal after the windshield wiper has passed the sensor is determined and used in order to control the frequency of wiping.
Abstract:
A windshield wiper assembly comprising two windshield wipers each driven by a separate motor is described in which a control provides switching signals for switching on and off the wiper motors so as to achieve relatively smooth running of the wipers. In particular wiping areas one motor is continuously switched on and only the other motor, in dependence on the difference of the angular positions of the two wipers, is controlled such that collision of the wipers is prevented when the wiping areas overlap.
Abstract:
In an intermittent windshield wiper system in which the time between wiping cycles depends upon the degree of dryness of the windshield and upon the speed of the wiper blades on the downstroke of the wiping cycle toward the dwell position of the wiper blades, a circuit is provided to regulate the speed of the motor on the down stroke making use of the same transistor device that is used in controlling the energization of the motor to achieve intermittent operation. The motor is a three-brush motor and speed regulation is achieved by deriving signals from one or two of the brushes and applying it to the input electrode of the transistor device. The regulated speed of the motor can be manually controlled to provide a manual adjustment to the sensitivity of the system to the degree of dryness of the windshield. The motor may be electrodynamically braked at the end of each wiping cycle and the electrodynamic braking circuit is also used to apply reverse current to the motor when the windshield wiper system is turned off to drive the windshield wiper blades to a depressed park position.
Abstract:
A windshield wiper control, e.g. for use in automobiles, receives information as to the amount of humidity on the windshield from a sensor (1) which is arranged within the area which is swept by the windshield wipers, and adjust the wiper frequency in relation thereto. The windshield wiper control includes a circuit (2) which remembers the signal from the sensor just after the windshield wiper has passed the sensor. The signal is compared to the signal directly from the sensor by a comparator (3). Having detected a certain change, the amplifier (4) is activated which turns on the wiper motor through a relay (5). The sensor may be of the capacitive type.
Abstract:
The glass pane of a vehicle window is provided on the surface of its central viewing area with a plurality of spaced, parallel linear heating resistors. First and second buses, disposed laterally of the central viewing area, extend transversely of the resistors and supply electric power thereto. A pair of moisture sensing, electrically conductive probes are provided on the pane at widely spaced zones away from the central viewing area. Each probe includes a first portion coextensive in length with a resistor and running parallel thereto. At least one of the probes has a second portion running parallel to one of the buses.
Abstract:
Windshield wiper control comprises a moisture detector in the form of two electrodes separated by a labyrinthine gap and positioned to be wiped by a windshield wiper blade. The motor controlling the wiper is started and stopped by a relay actuated by a control circuit containing the gap between the electrodes so as to start the wiper when the gap is bridged by moisture and stop it when the moisture evaporates. Means are provided for changing the threshold of response after the wiper has been started so that the wiper will stop when there is more moisture on the detector than is required to start it.