Multiplexed vehicle window wiper control
First Claim
1. In a window wiper system for an automotive vehicle including a control switch, another wiper control device and a wiper mechanism including a motor, a two-channel time division multiplex controller, said controller comprising:
- a multiplex encoder and a multiplex decoder interconnected by a conductor extending through the firewall over which a multiplex control signal is applied from the encoder to the decoder;
the multiplex encoder including means for generating the multiplex control signal as a cyclical waveform containing alternating cycles of different first and second periods wherein the duty cycle of the first period cycles is determined by the other wiper control device and the duty cycle of the second period cycles is determined by the control switch; and
the multiplex decoder including means for controlling the wiper mechanism in response to the respective duty cycles of the first period cycles and the second period cycles.
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Accused Products
Abstract
A window wiper system for an automotive vehicle provides multiplex encoding of a control switch signal and an additional wiper control signal in a two-channel multiplex control signal and decoding of the multiplex control signal by the wiper mechanism for control of wiper operation. The multiplex control signal is a cyclical waveform containing alternating cycles of different first and second periods wherein the duty cycle of the first period cycles is determined by the additional wiper control signal and the duty cycle of the second period cycles is determined by the control switch. The additional wiper control signal may be derived from a rain sensor, an intermittent delay control resistor or any other device on the passenger side of the vehicle firewall which generates a signal controlling wiper operation.
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Citations
14 Claims
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1. In a window wiper system for an automotive vehicle including a control switch, another wiper control device and a wiper mechanism including a motor, a two-channel time division multiplex controller, said controller comprising:
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a multiplex encoder and a multiplex decoder interconnected by a conductor extending through the firewall over which a multiplex control signal is applied from the encoder to the decoder; the multiplex encoder including means for generating the multiplex control signal as a cyclical waveform containing alternating cycles of different first and second periods wherein the duty cycle of the first period cycles is determined by the other wiper control device and the duty cycle of the second period cycles is determined by the control switch; and the multiplex decoder including means for controlling the wiper mechanism in response to the respective duty cycles of the first period cycles and the second period cycles. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. In a windshield wiper system for an automotive vehicle including a firewall separating the passenger compartment from the engine compartment, and further including a variable position control switch and another wiper control device located on the passenger side of the vehicle firewall, and a wiper mechanism including a motor located on the engine side of the firewall;
- a two-channel time division multiplex controller, said controller comprising;
a multiplex encoder located on the passenger side of the firewall and a multiplex decoder located on the engine side interconnected by a conductor extending through the firewall over which a multiplex control signal is applied from the encoder to the decoder, the multiplex encoder including; a base signal generator for generating a base signal having alternate first and second periods of different duration, first and second slave signal generators slaved to the base signal generator for generating first and second slave signals having the alternate first and second periods of the base signal but phase shifted in respect to the base signal by separate amounts determined by the output of the other wiper control device and the position of the control switch, respectively, and means for logically combining the base signal and the first and second slave signals to generate a cyclical multiplex control signal in which alternate cycles are of the first and second periods, respectively, and the duty cycles of the first and second period cycles are determined by the amount of phase shift between the base signal and the first and second slave signals, respectively; the multiplex decoder including means for controlling the wiper mechanism in response to the respective duty cycles of the first period cycles and the second period cycles; thereby to provide two-channel timed division multiplex operation in which the output of the other wiper control device is conveyed in one channel of the multiplex control signal as represented by the duty cycle of the first period cycles and the control switch position is conveyed in the other channel of the multiplex control signal as represented by the duty cycle of the second period cycles.
- a two-channel time division multiplex controller, said controller comprising;
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11. In a window wiper system for an automotive vehicle including a control switch, another wiper control device and a wiper mechanism including a motor, a two-channel time division multiplex controller, said controller comprising, in combination:
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an oscillator effective to generate an oscillating signal having alternating long and short periods and a ramp signal during each of the long periods; a first comparator effective to generate a first step signal when the ramp signal equals a control switch determined reference; a second comparator effective to generate a second step signal when the ramp signal equals a reference determined by the other wiper control device; a divider responsive to the oscillator to indicate alternating ones of the long and short periods; and a logic circuit responsive to the oscillator, the first and second comparators and the divider for generating a control signal comprising alternating ones of the first and second step signals in a first direction with each pair of adjacent first and second step signals being separated by a third step signal in a second direction opposite the first direction, the timing of the third step signals alternating between the beginning and end of corresponding short periods. - View Dependent Claims (12)
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13. In a window wiper system for an automotive vehicle including a control switch, a resistive rain sensor mounted on an external surface of a vehicle window and a wiper mechanism including a motor controlled at least in part in response to a rain sensor signal and in part in response to another wiper signal, apparatus for generating a wiper control signal comprising, in combination:
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means for determining periods of substantially equal time duration during which the rain sensor is alternately monitored and not monitored; means effective to provide a DC voltage across the rain sensor in a first direction during those periods in which the rain sensor is monitored and in an opposite direction during those periods in which the rain sensor is not monitored, whereby electrical polarization of water on the vehicle window is minimized; and means for generating the rain sensor signal in response to the resistance of the rain sensor during those periods in which the rain sensor is monitored and generating another wiper signal during those periods in which the rain sensor is not monitored.
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14. In a window wiper system for an automotive vehicle including a resistive rain sensor mounted on an external surface of a vehicle window and a wiper mechanism including a motor controlled at least in part in response to a rain sensor signal and in part in response to an additional wiper signal, apparatus for generating a wiper control signal comprising, in combination:
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means for generating an oscillating signal of alternating long and short periods; a dividing circuit responsive to the oscillating signal generating means to generate a divided signal which reverses polarity with each full cycle of the oscillating signal; means responsive to the dividing circuit to provide a DC voltage across the rain sensor which reverses polarity with the divided signal, whereby electrical polarization of water on the vehicle window is minimized; means for generating the rain sensor signal in response to the resistance of the rain sensor during long periods of the oscillating signal when the polarity of the DC voltage across the rain sensor is in a first direction; and means for generating the additional wiper signal during long periods of the oscillating signal when the polarity of the DC voltage across the rain sensor is in a second direction.
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Specification