Caterpillar Inc.
NOx sensor protection system

Abstract:

A NOx sensor protection system includes a flow control device forming an internal chamber with exhaust and shield gas ports and a NOx sensor. The flow control device is configured to selectively allow a flow of exhaust from an exhaust pipe to the NOx sensor when an internal combustion engine is operated with a first fuel, and to selectively direct shield gas from the shield gas port at an angle of 135.degree. to 180.degree. to the NOx sensor to inhibit the flow of exhaust from the exhaust pipe to the NOx sensor when the engine is operated with a second fuel.