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The continuous increase of pollutants and fine particulates is mainly caused by cars circulating worldwide. Therefore, it is necessary to replace internal combustion engines with the cleanest electric motors. The short term solution is represented by Hybrid Electric Vehicles (HEVs) due to its environmental and efficiency characteristics. In the present paper a dynamic feed-forward mathematical model for a hybrid vehicle performance analysis is proposed. Torque and power, pollutant emission, fuel consumption, battery pack state of charge, as well as speed and acceleration have been evaluated by means of simulation of United State and Japanese standard driving cycles. In order to carry out simulations on a real hybrid configuration, the model has been based on the powertrain installed on the Toyota Prius (Toyota Hybrid System - THS). A mathematical sub-model of each vehicle component has been implemented to simulate the real vehicle behavior in all possible running conditions.

One of the most important challenges in the design of a hybrid vehicle is the choice of the best control strategy for energy management. This work analyzes and discusses five different rules-based strategies. The authors' main targets were to understand how each strategy acts on the power split and how the operation points of both the Internal Combustion Engine and Electric Motor vary on efficiency maps. So, a critical review was produced of the strengths and weakness of different strategies found in scientific literature and out of it grew two new control plans.

The automotive industry needs a substantial revolution. It is necessary to replace conventional vehicles, equipped with highly polluting and very inefficient Internal Combustion Engines (if compared with the high efficiency of Electrical Motors), with clean, efficient electric vehicles (Zero Emission Vehicles). The electrical vehicles do not produce pollution and are characterized by high efficiency values (about 0.8) respect to ICE (about 0.27). In the transition from vehicles equipped with only ICE, to purely electrical vehicles, a fundamental step is represented by HEVs (Hybrid Electric Vehicles). This paper shows the development, the validation and the use of a numerical code for hybrid vehicle simulation. A quasi-static “backward” simulation code was developed and implemented for an ISA (Integrated Starter Alternator) configuration vehicle. The Willans line approach was implemented to create the HEV model.

In order to estimate the combustion process inside an Internal Combustion Engine it is fundamental to evaluate the molar fractions of the gases which constitute the burned mixture. A non linear set of equations must be solved to evaluate the mixture composition. The present paper deals with the study about the thermodynamics of combustion, using a new approach to solve the set of non linear equations by the Newton-Raphson method. In order to solve the non-linear set of equations describing the combustion process, a new first attempt solution for the Newton-Raphson numerical method has been evaluated and implemented. Starting from the combustion model presented in scientific literature by Benson, a new first attempt solution has been evaluated in order to have the numerical convergence of the model for a wide set of fuels and for a wide range of thermodynamic conditions. The combustion model is able to evaluate the molar fractions of the products of combustion.

In the current work, a heat release model, based on the First Law of the Thermodynamics, has been implemented using a genetic approach. Using this approach, the evaluation procedure of the calibration's constants becomes automatic and accurate. The more accurate is the evaluation of the calibration's constants, the more precise will be the calculation of the heat exchange between charge and cylinder walls, the evaluation of the gross heat release inside internal combustion engines, the evaluation of the rate of heat release, the mass fraction burned, as well as the combustion efficiency.

A new set of mathematical functions, that is able to describe gases' thermodynamic properties, has been developed. These functions have the form of a fifth order logarithmic polynomial (VoLP). They could be utilized for combustion processes, with “frozen composition” and “composition in equilibrium” evaluation. The VoLPs present several advantages: they are able to cover a wide range of temperatures with only a single mathematical function; they have an elevate accuracy and they present the possibility to extrapolate experimental data beyond the experimental temperature range. The VoLP coefficients have been evaluated through the least squares fit on the basis of experimental measurements (taken from scientific literature). The set of VoLPs gives the possibility to study the combustion phenomena and allows to describe specific heat at constant pressure, enthalpy, entropy and equilibrium constants for gases dissociation.

Several models for the evaluation of Gross Heat Release are often used in literature. One of these is the First Law - Single Zone Model (FL-SZM), derived from the First Law of Thermodynamics. This model presents a twice advantage: first it describes with accuracy the physic of the phenomenon (charge heat release during the combustion stroke and heat exchange between gas and cylinder wall); second it has a great simplicity in the mathematical formulation. The current paper deals with the implementation of a mathematical model, based on FL-SZM, to study the heat release due to the combustion phenomena in Internal Combustion Engines (ICEs). For purposes of chemical kinetic calculations, many of the major species have been included into the combustion products. In particular, seven gases (i.e. H2O, CO2, H2, O2, N2, CO and Ar) may also be assumed in chemical equilibrium.

In this paper, the authors have investigated a new neural network application for the determination of thermodynamic properties for various gases for internal combustion engines applications. The Neural Network has been trained using experimental data available in literature (specific heat at constant pressure, enthalpy, entropy and equilibrium constants for thirteen gases of practical interest inside ICE applications). In the present study a two-layer Elman network feedback from the first-layer output to the first layer input as well as “tansig” neurons in its hidden and out layers has been implemented. After the training, neural network has been tested through a comparison with the NASA equations and JANAF equations, showing the capability to cover with a single model wide range of temperature with an accuracy equal or greater than others mathematical function. Thermodynamic properties of gases have been calculated depending on temperature.

The present work deals with tests on a DI Diesel engine equipped with two different types of Common Rail injectors, the second one allowing a “smoother” fuel rate in the first stage of injection. The work aims at understanding how injection parameters and different injection rates may affect the combustion process in terms of in-cylinder pressure, noise and vibrations of the engine block. The tests performed for the same engine torque generally showed that engine speed, injection pressure and pilot injection duration are the most significant parameters that affect engine noise emissions. As regards the injection rate modulation, experiments showed that it is possible to reduce combustion noise at low engine speeds if the initial rate of injection is lower during the first stage of injection.

In this paper the effects of water injection in the intake pipe of a single-cylinder standard CFR engine are investigated from an experimental viewpoint. Research was carried out at AGIP Petroli and ISAB ERG Refineries of Priolo Gargallo (SR). Tests were performed according to ASTM Research and Motor Method. Water was supplied by a continuous and pulsed injection system. The engine was fed with low Octane Number (O.N.) base gasoline (cheap products, intermediate of refinery processes). The water to fuel mass flow rate ratio was varied in the range 0 to 2. Measurements of O.N. have shown that water injection virtually increases the water/fuel mixture O.N. and that it is possible to obtain a correct run feeding the engine with a low octane number fuel. The pollutant emissions measurements confirm the effectiveness of water injection in reducing the engine environmental impact.

The present work deals with the study of the dynamic behavior of a commercial injector subject to multiple injection strategy. The global spray characteristics have been investigate as well. These studies have been carried out using two numerical codes opportunely modified in order to better simulate the injection process. Comparisons between simulation results and experimental investigations have been made in order to test the reliability of the models. This paper aims at characterizing the macro and microscopic behavior of high pressure Diesel sprays generated by a common rail injector. If it is possible, purpose of this research is to validate and to extend the different correlations available in literature to the case of sprays generated by common rail injectors, especially at high injection pressures.

An AMESim model of the injection system has been developed introducing an automatic conversion of an experimental current signal into the force generated by the solenoid. The simulator realizes five multiple injections with different pauses. Using a dedicated current input, with faster rising and falling times, it was possible to realize smaller dwells between injections, optimizing the Bosch Common-Rail (C-R) system timing, without any mechanical modification. Using a commercial injector and an appropriate injection current trend, all the simulation results have been confirmed experimentally. Photographic sequences of a five holes mini-sac nozzle making five consecutive injections at 400, 800 and 1200 bar respectively were taken at ambient pressure and temperature. They showed that both spray penetration and cone angle at all operative conditions are very uniform and stable. Good agreement between experiments and simulations of needle lift has been obtained.

Water injection effects on combustion phenomena have been investigated for several years, from both a theoretical and experimental viewpoints due to the collaboration of AGIP PETROLI and ISAB ERG Refinery. In this paper the effects of water injection on diesel combustion are investigated and reported. Using single cylinder CFR engine Cetane (AGIP PRIOLO Engine 11361/1) cetane number (C.N.) and NOx emissions have been measured. Tests were performed according to ASTM Cetane Method (ASTM X2.7.4). Water was supplied by a continuous injection system. The engine was fed with a base diesel oil from DA1302 Refinery plant. The water to fuel mass ratio was varied in the range of 0 to 1.5. Apparent heat release and fuel mass burning rate analysis of the in-cylinder pressure data were carried out. The results of in-cylinder pressure data analysis have shown the effects of internal refrigeration on the compression work and on the combustion phenomena.

It is well-known that the reliability of calculations in ICEs depends on the accuracy of gases thermodynamic properties model. Several relationships modeling the composition of unburned and burned mixtures have been developed for computer use. In this paper, the authors have determined new relationships suitable also for ICEs applications, in order to calculate the enthalpy for various gases, and mixtures. These relationships can be used in the models describing the processes of intake, compression, combustion and expansion, to simulate a complete engine cycle and to foresee engine performance. These relationships have the functional form of a “V order Logarithmic Polynomial”, and they can be used in temperature range of practical interest.

Though analysed by a few researches, the practice of water injection in Spark Ignition Engines (SI-ICE) does not yield homogeneous results, owing to various typologies of engines used for experiments. In this paper the effects of water injection in the intake pipe are investigated from both a theoretical and experimental viewpoint. Pressure vs. time diagrams were recorded on a single-cylinder CFR engine at AGIP PETROLI, Priolo (CT). Tests were performed according to Research and Motor Method (ASTM). Water was supplied by a continuous injection system inclusive of comparatively high pressure pump. The engine was fed with low O.N. base gasoline (cheap products, intermediate of refinery processes). The water to fuel mass flow rate ratio was varied in the range 0 to 1.5. The NOx emissions measurements confirm the tremendous effectiveness of water injection in reducing the engine environmental impact.