Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Semiconducting metal oxide gas sensors

A number of new types of gas sensors based on semiconducting metal oxides have been developed using both thick and thin film technologies. These can be listed as follows.

This complex metal oxide sensor is capable of making cylinder selective lambda measurements in internal combustion engines. On the basis of such determinations a new type of vehicular engine control regime can be realized, allowing for decreased engine pollutant emissions and enhanced fuel economy on a global basis for internal combustion engines. These beneficial effects accrue due to the ability of this new sensor very quickly and continuously to determine the operational state of each cylinder in the engine, and via a fast feedback control loop, to decrease combustion fluctuations between the individual cylinders.

Sensors have been developed, based on 2 different oxidic materials, which are capable of detecting methane for both leak detection and lower explosive limit (LEL) applications.

A thin film sensor for higher hydrocarbons and solvents which has the capability to detect longer chain hydrocarbons, such as hexane, in the parts per million (ppm) range. One potential application for this device type is in leak detection in solvent storage areas.

Three different materials have been developed for the detection of carbon monoxide over a wide range of concentrations, with both threshold limit value (TLV) and flue gas sensing applications.

A sensor has been realized for the detection of vehicular nitric oxide emissions in the 1-5000 ppm range.

Two materials have been identified as showing acceptable performance characteristics for the detection of nitrogen oxides (NOx) in both TLV and flue gas applications.

A thick film sensor for ammonia has been designed to meet a number of end applications in DENOX processing, chemical industry cooling systems and cattle breeding.

Two materials have been developed in planar sensor architectures for the detection of oxygen in both combustion control and oxygen deficiency measurement applications.

A simple transition metal oxide sensor has been achieved for the detection of freon in the low ppm range. This has potential applications in refrigerant leak detection.

A complex metal oxide has been found to be suitable for the detection of alcohols in the TLV range.

A number of materials have been identified as potential hydrogen sensors. Two materials, one a simple metal oxide and the other a complex oxide, have exhibited particular selectivity for this gas, and planar sensors based on these materials have applications in both leak detection (eg, in monitoring of transformer oil) and LEL monitoring (eg, in mines).

A new sensor type has been developed based on a planar thermoelectric device. This sensor has been shown to be capable of detecting, at ambient temperature and in the presence of humidity, low concentrations of combustible gases including carbon monoxide and hydrogen.

Reported by

Siemens AG
81730 Muenchen
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