Catalytic converter diagnostic sensor

Abstract

Generally, the instant invention includes a method of using a sensor having an outer electrode including a gold-containing layer to diagnose the efficiency and useful life of a catalytic converter. The sensor having a gold-containing layer is positioned in an exhaust gas, combustion engine downstream from both the engine and the catalytic converter used to clean the exhaust. The sensor produces an voltage output responsive to the combustibles concentration in the exhaust gas. The voltage output from the sensor is measured and compared to a predetermined threshold correlated to a desirable combustibles concentrations in the exhaust stream or to a threshold output indicative of an inefficiently operating catalytic converter. An electrical output is then provided which is responsive to the comparison. The electrical output may be an indicator light, gauge or other devices for instructing the operator of a vehicle that the catalytic converter requires maintenance. The gold-containing layer of the sensor may be a gold alloy containing at least 28 percent by weight gold. The gold-containing layer may be the sole outer electrode of the sensor, or the gold-containing layer may be formed on a conventional platinum electrode of the sensor.

Dependencies are inferred from the claim text.