Abstract
There is a continuing need for high temperature NOx sensors for combustion environments due to government regulations and negative effects on ecosystems and health. Moreover, the Compression-Ignited-Direct- Injection (CIDI) engine is a leading candidate in the USA for new generation vehicles due to its high fuel efficiency. Controlling the emissions of oxides of nitrogen (NOx) is a key element for the successful implementation of the modern CIDI engine into future passenger vehicles. This can be made possible by both a sophisticated control of combustion and by an advanced exhaust emission control systems. Particularly important to both of these approaches is improved on board monitoring of the exhaust constituents NOx, PM, and oxygen (with emphasis on the first two).
Thus sensor development is needed for use with advanced emission control technologies and engine controls that will enable PNGV-candidate CIDI engines (operating on low-sulfur diesel fuel) to meet NOx and PM emissions targets (0.07 g/mi NOx and 0.01 g/mi PM) as well as other requirements (e.g., cost and efficiency). (Note that the NOx emission target eventually evolves to 0.03 g/mi in the 2007 time frame.) Therefore, a NOx sensor will enable the implementation of sophisticated control of combustion and the use of advanced exhaust emission control systems.
This paper presents a novel measurement system for determining total NOX concentration. Total NOX includes pure NO, pure NO2 and mixtures thereof. The measurement system comprises a gas conduit having an upstream end and a downstream end. The gas conduit carries a gas comprising NOX.