Abstract
By installing the oxygen sensor on the engine air intake side, an advanced EGR control becomes possible and fuel efficiency improvement can be expected. On the other hand, if the fuel vapor reaches the sensor element of zirconia-based solid electrolyte, the fuel vapor can ignite because the element is heated. The risk, however, is slight. Therefore, we evaluated the explosion-proofness of the protection tube by numerical simulation method we developed, and it was confirmed that the dimension between the inner and outer protection tubes has a great contribution.
