Gas sensor

摘要

In order to set the desired operating temperature of up to 1000 DEG C and maintain it independently of external influences, gas sensors based on semiconducting metal oxides are conventionally actively heated with the aid of a resistor element (8). However, during the heating, mechanical stresses may build up in the sensor which are so large that its substrate tears and it is thereby destroyed. The object of the invention is to provide a gas sensor in which no mechanical stresses which impair the sensor function build up during heating and operation. By using a resistor layer (8) consisting of titanate, local overheating effects of the sensor substrate (1) and thereby large temperature gradients are avoided. The temperature dependence of the electrical resistivity of titanate ensures that the heating power is reduced in hot sensor regions, but comparatively more heat energy is supplied to colder sensor regions. Motor vehicle exhaust gas sensors. <IMAGE>