Cycle by cycle NOx model for diesel engine control

• Published in: Applied thermal engineering Vol. 110; pp. 1011 - 1020
• Main Authors: Guardiola, C., Martín, J., Pla, B., Bares, P.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 05-01-2017
• Subjects: Adiabatic flame temperature; NOx; Reciprocrating engines; Resonance; Trapped mass; HCCI; MRE; NO; OP; HRL; SCR; CI; CAD; BMEP; HRR; Trapped mass; Reciprocrating engines; SOI; Adiabatic flame temperature; MAE; EGR; TDC; LNT; MAF; NOx; ECU; Resonance; LTC; PEMS
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2016.08.170

•A method for inferring NOx emissions from in-cylinder pressure signal is presented.•Sensor errors (aging or malfunctions) are avoided by relying only on in-cylinder pressure data.•The method has one cycle resolution, allowing good transient NOx estimation.•The presented method improves precision of current algorithms in 25%.•The model can be used for replace or improve Smart NOx sensor information.
This paper presents a model for on-line NOx estimation. The method uses both, low frequency components and high frequency components of in-cylinder pressure signal: it harnesses in-cylinder pressure resonance to estimate the trapped mass, and based on this measurement, a NOx model is adapted to estimate NOx emissions cycle by cycle.
In addition of the in-cylinder pressure signal, the procedure only requires from lambda and air mass flow to estimate NOx, so it can give a direct estimation of NOx or improve transient response and aging of current NOx sensors. The method was validated on a CI engine with high pressure EGR loop under steady and transient conditions showing errors below 10% and cycle by cycle time response.