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Device in a motor vehicle for indicating the outside temperature

  • US 4,770,543 A
  • Filed: 11/13/1986
  • Issued: 09/13/1988
  • Est. Priority Date: 11/13/1985
  • Status: Expired due to Term
First Claim
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1. Device in a motor vehicle for indicating an outside temperature, having an outside-temperature sensor and a speed sensor, an outside-temperature indicator inside the motor vehicle and an evaluation unit activating the outside-temperature indicator and having a memory, signals from the outside-temperature sensor and the speed sensor being inputs to the evaluation unit, which, during deceleration of the motor vehicle, at a lower limiting speed, as a function of the speed signal receives the temperature last detected by the outside-temperature sensor into the memory and activates the outside-temperature indicator to indicate this temperature, whereas, during the subsequent acceleration of the motor vehicle, at an upper limiting speed, as function of the selected speed signal the evaluation unit activate the outside-temperature indicator to blank out the temperature last indicated and to indicate a currently detected temperature, only after a speed dependent pre-determined delay time, comprising:

  • first threshold switch means, for receiving a selected speed signal from the speed sensor when the lower limiting speed is reached, and activating the memory;

    the memory being connected via an electronic switch to a comparator means which activates the outside-temperature indicator and to which the signal of the temperature currently detected by the outside-temperature sensor is likewise fed,wherein the comparator means includes means for activating the outside-temperature indicator to indicate the stored temperature only when the currently detected temperature exceeds the stored temperature by a pre-determined temperature amount, but activates the outside-temperature indicator to indicate the currently detected temperature, when the currently detected temperature is less than the amount of the stored temperature plus the pre-determined amount;

    second threshold switch means for receiving the signal from the speed sensor when the upper limiting speed is reached, and activating an integrator which is connected to a time base means and to a transducer, to which the signal from the speed sensor is likewise fed, with the integrator being connected to the electronic switch to open the switch after the expiration of a vehicle characteristic speed-dependent pre-determined delay time, so that, after the expiration of the pre-determined delay time, the comparator means activates the outside-temperature indicator to indicate the currently detected temperature.

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