The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 13, 1987
Filed:
Apr. 21, 1986
Gerd Wallenfang, Cologne, DE;
Kloeckner-Humboldt-Deutz AG, Cologne, DE;
Abstract
A temperature measuring device for recording large changes in temperature, especially for recording the temperatures in an internal combustion engine. An NTC resistor is connected with a constant source of voltage via a dropping resistor and the drop in voltage across the NTC resistor is a gauge for the temperature. Because of the characteristics of the NTC resistor, measurement of low temperatures is possible with a high ohmic dropping resistor but accurate measurement of high temperatures is not possible. The opposite is true when using a low ohmic dropping resistor. In one embodiment of the disclosed device, it is possible to switch at a predetermined frequency the resistance of the dropping resistor circuit between a high ohmic and a low ohmic value, whereby the correspondingly produced output signal indicates the recorded temperature over the whole temperature range with a satisfactory degree of accuracy. Alternatively, the recorded temperature output signal may be fed to a comparer computer together with a control frequency to produce an output voltage with a probe ratio which is synchronized with the average recorded temperature thereby obtaining a greater gradient at the high and low temperature portions of the voltage versus temperature curve and more accurate measurement of high and low temperatures.