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The work aims at analysing the energetic performances of monolith and pellet emission control systems using unidirectional and reverse-flow design (passive and active flow control respectively). To this purpose a one-dimensional transient model has been developed and the cooling process of different system configurations has been studied. The influence of the engine operating conditions on the system performances has been analysed and the fuel saving capability of the several arrangements has been investigated. The analysis showed that the system with active reverse flow and pellet packed bed design presents higher heat retention capability. Moreover, the numerical model put in evidence the large influence of the exhaust gas temperature on the energy efficiency of the emission control systems and the significant effect of unburned hydrocarbons concentration.

A zero-dimensional dynamic model was developed in the Matlab/Simulink® environment to predict the behaviour of a variable-displacement lubricating vane pump for internal combustion engine applications. Based on the geometric and kinematic characteristics of the pump, the model allows predictions of the pressure evolution in each chamber of the pump and in the delivery piping, by employing an integrative-derivative approach. Simulation results were compared with experimental data of pressure transducers, which were fitted along the periphery of the pump case and in the delivery channel. The analysis of the experimental data shows that the pressure dynamics, which is experienced by the transducers, is in some cases quite different from the pressure dynamics in the pump chambers and produces pressure peaks which are not actually present in the original signal. The pressure transducers output was then also modelled in order to properly compare simulation results and experimental data.

Variable-displacement lubricating pumps are an attractive solution for reducing fuel consumption and emissions in motorcycle engines. In this prospective, modeling and experimental analysis are very useful means for a deeper understanding of pump operation and for effectively implementing pump control. Zero-dimensional simulation results of a 7-vane pump were compared with the experimental data of dynamic piezo-resistive pressure transducers fitted into the casing of a pump prototype, which was operated under steady-state conditions at different rotational speeds and eccentricity values. The experimental data exhibit oscillations which were explained by taking into account the pressure transducers dynamics, as a result of the transducer location in the pump casing, of the air dissolved in the hydraulic fluid and of the geometry of the tubing/transducer system.

The aim of the present work is to analyse and compare the energetic performances and the emissions conversion capability of active and passive aftertreatment systems for lean burn engines. To this purpose, a computational one-dimensional transient model has been developed and validated. The code permits to assess the heat exchange between the solid and the exhaust gas, to evaluate the conversion of the main engine pollutants, and to estimate the energy effectiveness. The response of the systems to variations in engine operating conditions have been investigated considering standard emission test cycles. The analysis highlighted that the active flow control tends to increase the thermal inertia of the apparatus and then it appears more suitable to maintain higher temperature level and to guarantee higher pollutants conversion at low engine loads after long full load operation.

The present study aims at analyzing the flow field within a Lean NOx Trap (LNT). To this purpose a twofold approach based on the synergic use of numerical and non-intrusive experimental techniques was adopted. The measurements were carried out at a steady flow rig in terms of global performances and local velocity measurements. In particular, mass flow rates and pressure drops were used to define the global fluid dynamic efficiency of the system, while the Laser Doppler Anemometry (LDA) technique was employed to determine the flow field within the aftertreatment apparatus. At the same time, a finite volume CFD code was adopted for the numerical analysis. The comparison between experimental and numerical data displayed a good agreement in terms of global and local quantities. Specifically, the numerical code well-reproduced the main structure within the emission control system.

An experimental investigation was conducted on a production 4-cylinder, MPI small S.I. engine, 1.2 dm3 displacement, which was operated at 4000 rpm full load, then brought to idle for a short period and finally switched off. As the coolant flow stops while the metal temperature is quite high, a fraction of coolant vaporizes, pressure and temperature increase and part of the coolant is lost through the radiator pressure relief valve. This phenomenon is often known as after-boiling. Tests were carried out for different values of the idle operation time, while coolant conditions and metal temperature at 26 points of the engine head and liner were monitored for 2 mins before and 15 mins after engine switch-off. The volume of leaked coolant as well as the start and finish of the expulsion process were also recorded.

This work presents a methodology for the optimal thermal management of different powertrain devices, with particular regard to ICEs, power electronic units (IGBT) and PEM Fuel cells. The methodology makes use of Model Predictive Control by means of a zero-dimensional model for the heat transfer between the device and the coolant. The control is based on the careful monitoring of the coolant thermal state by means of a metrics for the occurrence of nucleate boiling. The introduction of an electrically driven pump for the control of the coolant flow rate is considered. The effectiveness of the proposed approach is presented with reference to an ICE operation. Experimental tests show the advantages of the methodology during warm-up, under fully warmed operation and for the avoidance of after-boiling.

The road transportation sector is undergoing significant changes, and new green scenarios for sustainable mobility are being proposed. In this context, a diversification of the vehicles’ propulsion, based on electric powertrains and/or alternative fuels and technological improvements of the electric vehicles charging stations, are necessary to reduce greenhouse gas emissions. The adoption of internal combustion engines operating with alternative fuels, like methanol, may represent a viable solution for overcoming the limitations of actual grid connected charging infrastructure, giving the possibility to realize off-grid charging stations. This work aims, therefore, at investigating this last aspect, by evaluating the performance of an internal combustion engine fueled with methanol for stationary applications, in order to fulfill the potential demand of an on off-grid charging station.