Motivated by the fact that the real driving NO x emissions (RDE) of conventional diesel vehicles can exceed the legislation norms by far, a concept for the control of RDE with a diesel parallel hybrid electric vehicle (HEV) is proposed. By extending the well-known equivalent consumption minimization strategy (ECMS), the power split degree of freedom is used to control the NO x emissions and the battery state of charge (SOC) simultaneously. Through an appropriate formulation of the problem, the feedback control is shown to be separable into two dependent PI controllers. By hardware-in-the-loop (HIL) experiments, as well as by simulations, the proposed method is shown to minimize the fuel consumption while tracking a given reference trajectory for both the NO x emissions and the battery SOC.
This paper presents an original methodology for the instantaneous in-cylinder pressure waveform reconstruction in a spark-ignited internal combustion engine. The methodology is based on the existence of a linear correlation, characterized by frequency response functions, between in-cylinder pressure and engine speed signals. This correlation is experimentally verified and evaluated by simultaneous measurements of the above-mentioned quantities. The evaluation of different frequency response functions, one for each steady-state condition investigated, allows recovering the pressure waveform even under other engine running conditions (i.e., transients). In this way, during on-board operation, the pressure waveform could be recovered using only the engine speed signal, already present in current production electronic control units. In this paper the signal processing methodology and some experimental results, obtained during transient tests, are presented. The methodology could be interesting for the development of advanced engine control strategies aimed at the management of the torque generated by the engine. As an example, traction control in drive-by-wire systems could be a possible challenging application. The in-cylinder pressure reconstruction performed using the frequency response functions, in fact, allows the evaluation of the indicated torque. An important characteristic of this methodology is, furthermore, the diagnostic capability for the combustion process, that is guaranteed by the linear correlation between in-cylinder pressure and instantaneous engine speed waveforms. Also in presence of a misfiring cylinder, when the instantaneous engine speed waveform is strongly affected by the absence of combustion, the reconstructed in-cylinder pressure shows a good agreement with the measured one. The experimental tests have been conducted in a test cell using a four-cylinder production engine. It has to be noted, anyway, that the same methodology can be applied to engines with a higher number of cylinders.
The objective of the present work is the development of a closed-loop individual cylinder spark advance control strategy that allows maximizing torque production while keeping the knocking phenomenon at levels considered safe for the engine components. The research activity has consisted of several phases: the first one was focused on the analysis of the relationship between knocking level and indicated mean effective pressure. The main result of this preliminary phase is a methodology for identifying target values of the chosen in-cylinder pressure based knocking index. A subsequent phase of the work has been devoted to a correlation analysis between pressure-based knocking indexes and knocking indexes obtained by processing other combustion-related signals (engine block vibration and ion current), showing that the ion current based system that has been developed allows reaching high correlation levels. Finally, in order to achieve the target knocking levels, the spark advance control strategy proposed here consists of two parallel contributions: a slower, adaptive and statistically-based contribution, and a fast but range-limited term. The process of designing the controller has been particularly fast and cost-effective, due to the development of a specific software environment that allows verifying the performance the controller would achieve when applied to the actual engine. Such structure may be described as a software rapid control prototyping environment, since an experimental database has been used to reproduce in a simulation environment the response of the controlled system (the engine) coupled to the spark advance control system. The proposed control strategy has been successfully implemented on a V12 6.0 liter high performance engine, allowing to maximize output torque while protecting engine components from knock-related damage.
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