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This work aims at investigating the optimal configuration of an internal combustion engine fueled with bio-ethanol for improving its brake power and efficiency as well as for reducing the NOx emissions, in stationary applications. A turbocharged spark ignition engine characterized by a single-point injection was preliminarily considered; subsequently, a direct injection configuration was investigated. For both cases, a 1-D numerical model was developed to compare the injection configurations under stoichiometric conditions and different spark timings. The analysis shows that the direct injection guarantees: a limited improvement of brake power and efficiency when the same spark timing is adopted, while NOx emissions increases by 20%; an increase of 6% in brake power and 2 percentage points in brake thermal efficiency by adopting the knock limited spark advance, but an almost double NOx emissions increase.

To pursue the target of the “net-zero” emission by 2050 and to reduce the most harmful pollutant emissions from road traffic, more specifically of particulate matter (PM), the transportation sector is subject to significant changes. A transition from internal combustion engine passenger cars (ICEVs) to hybrid vehicles (HEVs) and battery-electric vehicles (BEVs) is taking place. This transition, however, must be carefully examined from different perspectives, as hybridization/electrification may not reduce the levels of PM and CO2 as much as expected. In this work, exhaust and non-exhaust PM emissions of a vehicle powered with an internal combustion engine, and of the same vehicle in plug-in hybrid and electric configurations is carried out, by using the emission factors approach.

In this work, a dynamic 0-D electro-thermal model of a lithium-polymer battery for automotive applications is presented. The model predicts the battery temperature during its charging/discharging phases under different environmental and operating conditions, by considering the requested power or current, the coolant flow rate and its temperature as model inputs. The model was first validated with experimental data carried out at the test bench where only the convective heat transfer between the battery and the ambient air was considered. The accuracy of the internal heat generation model was experimentally assessed for different current discharge rates. Then, a liquid cooling system was designed on purpose, assembled, and installed on the battery at the test bench for the improvement of the model predictions in liquid convection conditions.

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.

This work is developed in the framework of an industrial R&D project, titled ARIA (Active Responsive Intelligent Aerodynamics), having the main goal to improve the efficiency of a vehicle by introducing active aerodynamics supported by innovative actuation systems. The work focuses on the development of a new aesthetic Active Grille Shutter (AGS), which, differently from the currently marketed vehicles, does not include the presence of a grille in front of it. In addition, an innovative actuation system, based on the adoption of Shape Memory Alloys (SMA) is being investigated for the new AGS, with the main goal to exploit the advantages arising in terms of increased efficiency coupled with a marked weigh reduction. The proposed analysis aims, at first, at evaluating the effects of different AGS configurations on the drag coefficient, Cx, of the vehicle and on the related benefits.

The dynamic effects of a coolant flow rate variation on knock tendency are experimentally investigated on a small S.I. engine. The analysis concerns the transient response of the unburned gas temperature and the knock onset to a step variation in load and coolant flow rate. This phenomenological investigation aims at preventing knock through a proper thermal management as an efficient alternative to the currently adopted strategies. Moreover, the proposed approach may result particularly useful for hybrid-electric powertrain, where the engine is expected to operate in the highest efficiency region by adopting high compression ratios and full stoichiometric map. The analysis is carried out through an experimental campaign, where the control of cylinder wall temperature is achieved by means of an electrically driven water pump. The spark advance and the air/fuel ratio have been properly varied in order to operate with advanced spark timing and stoichiometric mixture at full load.

The possibility to mitigate the knock onset by means of a controlled coolant flow rate is investigated. The study is carried out on a small displacement, N.A. 4-valve per cylinder SI engine. The substitution of the standard belt-driven pump with an electrically driven one allows the variation of the coolant flow rate regardless of engine speed and permits, therefore, the adoption of a controlled coolant flow rate. The first set of experimental tests aims at evaluating the engine operating condition and the coolant flow rate, which are more favorable to the knock onset. Starting from this condition, subsequent experimental tests are carried out for transient engine operating conditions, by varying the coolant flow rates and evaluating, therefore, its effects on cylinder pressure fluctuations. In all the experiments, the spark advance and the equivalence ratio are controlled by the ECU according to the production engine map.

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 after-boiling phenomenon in internal combustion engines can occur when the engine is suddenly switched-off after a period of prolonged high-load operation. In this case, the coolant flow rate stops while the engine wall temperature is quite high; therefore, some evaporation occurs, pressure in the cooling circuit increases and part of the coolant is lost through the radiator relief valve. The control of the coolant flow rate by means of an electric pump instead of the standard belt driven one offers the possibility of overcoming this issue. In the present paper, a model-based control of the coolant flow rate is proposed in conjunction with the adoption of an electric pump in the engine cooling system. Experimental tests and simulations have been carried out starting from high speed-high load engine operation; the engine was then brought to idle and, shortly after, switched-off.

In this paper, we propose a novel control architecture for dealing with the requirements arising in a cooling system of an ICE. The idea is to take advantage of the joint action of an electric pump and of an ad-hoc regulation module, which is used to determine adequate flow rates despite engine speeds. Specifically, a robust Model Predictive Control approach is exploited to take care formally of input/output constraints and disturbance effects of the resulting lumped parameter model of the engine cooling system, which incorporates the nucleate boiling heat transfer regime. Numerical simulations and test rig experimental data are presented. The results achieved show that the proposed control scheme is capable of providing effective and safe cooling while mitigating disturbance effects and minimizing coolant flow rates when compared with the action pertaining to standard crankshaft driven pumps.

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.

An innovative control strategy, which is based on the Robust Model Predictive Control (MPC) methodology, was developed with the purpose of optimizing the engine thermal management; the proposed control strategy adjusts the coolant flow rate by means of an electric pump, in order to bring the cooling system to operate around the onset of nucleate boiling. In the present paper, the advantages of the proposed cooling approach are evaluated along the NEDC homologation cycle, which was both simulated and replicated by means of laboratory tests; the latter include coolant, lubricant and wall temperature measurements. Special attention was reserved to the warm-up period. The case considered herein is that of a Spark Ignition engine, about 1.2 dm3 displacement, and a comparison with standard crankshaft driven pump is included.