Adaptive NOX Soft Sensor for Aftertreatment of Diesel Engines

As environmental regulations become stricter, diesel engines must become cleaner. Hence, in addition to combustion control, aftertreatment of the exhaust is important to reduce emissions involving NO X and diesel particulate matter (DPM). NO X is eliminated by a chemical reaction with ammonia, which is generated by hydrolysis of injected urea. Although the NO X concentration must be accurately detected to ensure the appropriate quantity of urea is used, the response speed of the current NO X sensor is too slow to follow transient operations. In this paper, a new NO X adaptive soft sensor for aftertreatment of diesel engines is described, and its basic characteristics are confirmed via an engine bench test.