Lothar Raff

Heated zirconia oxygen sensor for stoichiometric and lean air-fuel ratios

This publication describes the design and operation of an electrically heated ZrO/sub 2/ sensor and demonstrates its advantages in comparison to the present unheated sensor in a lambda = 1 system. Control ability down to very low exhaust temperatures, minimized temperature dependence and reduced aging effects result in lower emissions with the heated sensor. The application advantages in a lambda = 1 system are discussed. The second part of the paper describes the properties of this heated sensor for measurement of lean exhaust gas. The lambda-range 1.0 to 1.5 can be covered without any additional temperature compensation with sufficient accuracy and stability over life time.