ECU-oriented models for NOx prediction. Part 1: a mean value engine model for NOx prediction

Abstract

The implantation of NO x sensors in diesel engines is necessary in order to track emissions at the engine exhaust for diagnosing and control of the after-treatment devices. However, the use of models is still necessary as the output from these sensors is delayed and filtered. The present paper deals with the problem of NO x estimation in two parts covering modelling and data fusion of a sensor signal and the model, respectively. This is the first part where a NO x model is developed based on a nominal set-point relative fitting of the NO x with a series of corrections for accounting with variations on λ −1 , temperatures and other signals. The NO x model combines look-up tables with physical-based equations and is designed for being implemented on commercial ECUs. The relatively low calibration effort and the reported results presented with a turbocharged diesel engine shows the feasibility of the model and the possibilities for on-board implementation. This paper is the first part of a two-parts paper dedicated to the on-board estimation of NO x .

Cycle by cycle NOx model for diesel engine control

“…Ranging from physics-based models, which rely on complex thermodynamics and combustion processes, to black box models, which have no representation of physics phenomena, NOx modelling has been a trade-off between physics fidelity, calibration effort and computational cost [13,14,15].…”

Optimal Control as a method for Diesel engine efficiency assessment including pressure and NO x constraints

“…Regarding the NO x constraint, an additional model to compute the NO x emissions associated to a given HRL should be used. There are several low computational cost models to predict NO x emissions in the literature, some of them rely on correlations that provide the NO x emitted depending on the operating conditions [12], [13], while others, more physically based, use the evolution of the thermodynamic variables during the cycle to compute the in-cycle evolution of the NO x . In the present study, one of the last kind proposed by [9] has been used because of its good accuracy and the easy combination with the combustion model previously presented.…”

Solución analítica de un filtro de Kalman estacionario para la observación de deriva en modelos de emisiones de NOx en motores diesel de automoción

“…Existe una amplia variedad de modelos en la bibliografía (Schilling, 2008), como aquellos basados en redes neuronales (Arsie et al, 2010), diseño de experimentos (Desantes et al, 2012) o modelos de caja negra (Winkler-Ebner et al, 2010;Karlsson et al, 2010). En el presente trabajo se ha seleccionado un modelo de valor medio que combina mapas ajustados por diseño de experimentos con ecuaciones básicas de conservación de la masa y energía y que se describe completamente en Guardiola et al (2014b).…”

“…Las variables del modelo de espacio de estados (1) se definen como sigue: u k ∈ R es NO x,m (k − τ) y corresponde a un modelo de NO x similar al presentado en (Guardiola et al, 2014b) cuya señal es convenientemente retrasada con el retraso puro τ ∈ Z + para tener en cuenta el retraso del sensor; y k ∈ R…”