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[EN] Accurate cylinder charge and composition estimation is crucial for proper combustion control, however, current sensors and models show different issues for transient estimation. The work presented in this paper combines a novel technique for trapped mass estimation, which relies on the in-cylinder pressure resonance, with on-board engine sensors by taking into account the intake manifold dynamics with a closed-loop observer. The resonance method provides a measurement of trapped mass with one cycle resolution. This measurement feeds a Kalman filter to improve the transient and steady response of the intake charge and composition estimation. The observer was validated in a four stroke heavy-duty engine, showing fast transient capabilities and an adequate steady-state accuracy., This work was partially supported by Ministerio de Economia y Competitividad through Project TRA2016-78717-R. C. Guardiola research has been partially financed by the Fulbright Commission and the Spanish Ministerio de Educacion, Cultura y Deporte through grant PRX14/00274.

Nowadays the increasing automotive market competition together with the worsening of the environmental pollution leaded to the development of complex engine systems. Innovative control strategies are needed to simplify and improve the Engine Management System (EMS), moving towards energy saving engines and complying with the restrictions on emissions standards. In this scenario the application of methodologies based on the in-cylinder pressure measurement finds widespread applications. Indeed, the in-cylinder pressure signal provides direct in-cylinder information with an high dynamical potentiality, that is fundamental for the control and diagnosis of the combustion process. Furthermore, the in-cylinder pressure measurement may also allow reducing the number of existing sensors on-board, thus lowering the equipment costs and the engine wiring complexity. This paper focuses on the detection of the Air-Fuel ratio and the in-cylinder trapped mass after the intake valve closing from the in-cylinder pressure signal. The Air-fuel ratio estimation might allow replacing the lambda sensor, the estimation method is based on a statistical approach. The in-cylinder trapped mass estimation gives the opportunity to by-pass the CO2 measurement for the evaluation of the EGR rate, in this case the Δp method is proposed. The developed techniques were validated vs. experimental data measured at the engine test bench on a Common-Rail turbocharged Diesel engine. The results show a good accuracy in predicting Air-Fuel ratio and in-cylinder trapped mass in a wide engine operating range. Because of both the low computational burden and the good results, these methodologies are suitable to be implemented on-board.

[EN] 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. (C) 2016 Elsevier Ltd. All rights reserved.

An analysis of in-cylinder gas density and oxygen mass concentration (YO 2 ) impact on the mixing and oxidation processes and the final soot emissions in conventional high temperature diffusive Diesel combustion conditions is presented in this paper. Parametrical tests were performed on a single cylinder heavy duty research engine. The density was modified adjusting the boost pressure following two approaches, maintaining the YO 2 either before or after the combustion process. The YO 2 was modified by diluting fresh air with exhaust gas maintaining a constant density. The possibility of controlling the soot emissions combining both parameters (YO 2 and density) is evaluated and, in a final part, the NO X emission results are also addressed. Results show that YO 2 has a strong effect on both mixing and oxidation processes while density affects principally the mixing process. Both parameters affect the final soot emissions. The density modification through adjustment of boost pressure modifies the trapped mass and has a strong impact on the evolution of YO 2 (thus on the evolution of the mixing process) during combustion. If the density is increased maintaining constant the YO 2 at the beginning of the combustion, the NO X -Soot trade-off is enhanced.