Abstract: Methods and systems for detecting a temperature TO of a remote object are provided. The method includes storing in memory, a lookup table relating an output voltage of an infrared sensor to a temperature sensed by the infrared sensor V(TO, TA), determining a temperature sensor voltage output corresponding to a temperature TA proximate the infrared sensor, determining a first voltage as a function of the temperature TA proximate the infrared sensor and a reference temperature TREF, V(TA, TREF), determining a second voltage as a function of the temperature of the object TO and the reference temperature TREF, V(TO, TREF) by combining the determined temperature sensor voltage output and the first voltage, and determining a temperature of the object TO from the lookup table using the second voltage.

Abstract: A temperature sensor for a motor vehicle comprises a composite of PTC and NTC thermistors (1, 2, 3) whose overall temperature characteristic (c) is negative with a plateau (P) centered on the normal working temperature (88.degree. C.) to be sensed, so that tolerances in the sensing system and normal fluctuations of the working temperature will tend not to be registered by the vehicle temperature gauge. Thus only abnormal variations in temperature caused by a fault or overload condition will be indicated.