A comparative study on mean value modelling of two-stroke marine diesel engine

In the present paper, two mean value modelling approaches of varying complexity, capable of simulating two-stroke marine Diesel engines, are presented. Both approaches were implemented in the computational environment of MATLAB Simulink®. Simulation runs of transient operation cases of a large two-stroke marine Diesel engine were performed. The derived results were validated against previously published data are used for comparing the two modelling approaches and discussing the advantages and drawbacks of each

Modelo matemático de tipo valor medio de un motor de combustión interna y estimación de estados usando técnicas Bayesianas

En el presente trabajo se obtiene el modelo matemático orientado al control de un motor de combustión interna de ignición por chispa. El modelo aplica ecuaciones de primeros principios con no-linealidades y parámetros desconocidos. Las ecuaciones aplicadas al modelo están explicadas mediante relaciones termodinámicas conocidas en la literatura como \Mean Value Engine Modelling" (MVEM). La MVEM describe un modelo matemático orientado al control para las máquinas de combustión interna de ignición por chispa. Este enfoque simplifica los procesos termodinámicos del motor en subsistemas independientes de entrada-salida, continuos en el tiempo. El modelo resultante está definido por tres submodelos: dinámica del aire en el múltiple de admisión, dinámica del proceso de combustión y dinámica rotacional en el eje de salida. El modelo es compactado como un sistema en variables de estado, el cual se discretiza para aplicar técnicas de estimación bayesianas con el fin de solucionar un problema de estimación del estado del modelo dinámico del motor de combustión. Para ello, se construye la función de densidad de probabilidad (PDF) de los estados sobre la base de la información disponible (mediciones); se asume una distribución gaussiana de las variables no lineales del estado. Se obtiene un modelo con un grado de exactitud aceptable y un algoritmo de filtrado que aproxima con alto grado de exactitud los estados del model

investigation of the energy requirements for the on board generation of oxy hydrogen on vehicles

Abstract The present study investigates the energy needs for the on-board generation of oxyhydrogen (HHO) used as fuel additive on vehicles. HHO production is performed through the use of an alkaline electrolyzer, directly taking energy from the equipped internal combustion engine. A longitudinal vehicle dynamic model is used to evaluate the driving power to be supplied by the engine for two reference speed profiles, NEDC and WLTC. The performed investigation determines the engine brake thermal efficiency gain required to ensure HHO production without increase in fuel consumption. The results can be used as guidelines for the development of on-board control strategies

Modeling and control of a Diesel HCCI engine

International audienceThis article focuses on the control of a Diesel engine airpath. We propose a detailed description of the airpath of a Diesel HCCI engine supported by experimental results. Moreover, we propose a simple, yet innovative, motion planning control strategy. At the light of this study, we can finally conclude, with supportive results, that motion planning is indeed an appropriate solution for controlling the airpath dynamics

Development and validation of a "crank-angle" model of an automotive turbocharged Engine for HiL Applications

Abstract Management and diagnostic functions are playing a key role in the improvement of engines performance and in the reduction of fuel consumption and pollutant emissions especially in automotive applications. As widely documented in the open literature, design, validation, and testing of control systems take actually advantage of theoretical models to a great extent, due to their capabilities to reduce development time and costs. However, the increasing complexity of present engines and related management systems give rise to challenging issues in the development and applications of mathematical models. The paper describes the improvements introduced in the original Library set up by the authors in Simulink® for "control-oriented" simulation of Internal Combustion Engines (ICE) and powertrains. The tool has been initially developed to build up Mean Value Models (MVMs) of automotive engines for "real-time" simulations, and in that version has been used in several HiL applications. Due to the enhancing requirements in engine control functions, the Library has been recently improved to allow for "crank-angle" simulation of the engine. To this extent models of intake and exhaust valves and of in-cylinder processes have been built up (where combustion process is described following a classic single-zone approach based on a proper Heat Release Rate, HRR). An original algorithm has been developed to run the model at a computational speed comparable with real time even with a resolution of 1 degree CA for in-cylinder calculation. Modeling tools have been applied to the simulation of a four-cylinder turbocharged Diesel engine with Exhaust Gas Recirculation. Through a specific calibration procedure, the model was fitted on a typical layout of an automotive Diesel engine and then validated comparing simulation results with experimental data measured by the OEM on a test bench. With a very low computational time, the model showed interesting capabilities in the simulation of the behavior of automotive engines with "crank-angle" resolution and therefore has been used in an original HiL application developed by the authors

Computational investigation of ship propulsion performance in rough seas

In this paper, the performance of a merchant vessel propulsion system during acceleration is evaluated under different sea state conditions. The various parts of the main propulsion system have been modelled by using a mean value approach for the engine model with differential equations to calculate the engine crankshaft and turbocharger shaft speeds. Ship propulsion system has been modelled by using differential equations to calculate vessel speed and speed of advance. The output of the engine model has been validated under steady conditions according to the main engine shop test performance data. The calm water resistance is calculated following the ship sea trials results, whilst Wageningen polynomials have been used to simulate the propeller performance for the given hull resistance and speed. In order to estimate the added resistance for different weather conditions, the recommended procedures by International Standards have been followed. Then, the propulsion system performance is evaluated, both in calm water and waves, to investigate the main engine response during acceleration. Based on the simulation results, the propulsion system performance is discussed in respect for the engine response and vessel hydrodynamic performance, predicting the maximum vessel speed for the available engine power and speed