Mitsubishi Jidosha Kogyo Kabushiki Kaisha

Masaru Mikita

Shigekazu Yamauchi

Masashi Tanaka

Masahi Tanaka

An oxygen sensor testing device having an oxygen sensor disposed in a rear stage of a synthetic gas passage to evaluate the oxygen sensor using a synthetic gas supplied to the synthetic gas passage, in which a sulfur dioxide gas passage supplied with sulfur dioxide gas communicates with a front stage of the synthetic gas passage to supply sulfur dioxide gas to the synthetic gas passage, thereby enabling exact evaluation of the oxygen sensor using the synthetic gas having composition close to actual exhaust gas containing sulfur dioxide.

Testing device for an oxygen sensor

An oxygen sensor having a detecting element for detecting the concentration of oxygen contained in a subject gas. The subject gas reaches the detecting element through a carrier carrying a substance which adsorbs or desorbs the oxygen in the subject gas in accordance with the partial pressure of the oxygen. Thus, the detecting element is prevented from being corrupted by O.sub.2 or CO. Even though the oxygen sensor is temporarily exposed to excessive O.sub.2 or CO, therefore, the responsiveness of oxygen concentration detection to be effected thereafter is improved. Cerium oxide or lanthanum oxide may be suitably used as the oxygen adsorbing or desorbing material. The carrier may be pellets surrounding the oxygen detecting element, or a protective layer or a buffer layer formed on the surface of the detecting element. Alternatively, the carrier may be formed independently of the oxygen sensor so as to be disposed in an exhaust passage on the upper-course side of the oxygen sensor. The oxygen sensor of the present invention is adapted for use in an air-fuel ratio control apparatus of an internal combustion engine.

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Kyoto, Japan

Masaru Mikita