Gas Exchange and Injection Modeling of an Advanced Natural Gas Engine for Heavy Duty Applications

The scope of the work presented in this paper was to apply the latest open source CFD achievements to design a state of the art, direct-injection (DI), heavy-duty, natural gas-fueled engine. Within this context, an initial steady-state analysis of the in-cylinder flow was performed by simulating three different intake ducts geometries, each one with seven different valve lift values, chosen according to an estabilished methodology proposed by AVL. The discharge coefficient (Cd) and the Tumble Ratio (TR) were calculated in each case, and an optimal intake ports geometry configuration was assessed in terms of a compromise between the desired intensity of tumble in the chamber and the satisfaction of an adequate value of Cd. Subsequently, full-cycle, cold-flow simulations were performed for three different engine operating points, in order to evaluate the in-cylinder development of TR and turbulent kinetic energy (TKE) under transient conditions. The latest achievements in open source mesh generation and motions were applied, along with time-varying and case-fitted inizialization values for the fields of intake pressure and temperature. Finally, direct-injection of natural gas in the cylinder was incorporated in full-cycle simulations, to evaluate the effects of injection on charge motions and charge homogeneity at the estimated spark timing. Three specific engine operating points were simulated and different combinations of turbochargers and valve lift laws were tested. Results consistency was verified by means of validations with data from 1D simulations and literature

Combined Experimental and Numerical Investigation of the ECN Spray G under Different Engine-Like Conditions

A detailed understanding of Gasoline Direct Injection (GDI) techniques applied to spark-ignition (SI) engines is necessary as they allow for many technical advantages such as increased power output, higher fuel efficiency and better cold start performances. Within this context, the extensive validation of multi-dimensional models against experimental data is a fundamental task in order to achieve an accurate reproduction of the physical phenomena characterizing the injected fuel spray. In this work, simulations of different Engine Combustion Network (ECN) Spray G conditions were performed with the Lib-ICE code, which is based on the open source OpenFOAM technology, by using a RANS Eulerian-Lagrangian approach to model the ambient gas-fuel spray interaction. Foremost, the main scope of the activity was to identify the most accurate numerical set-up in terms of atomization ad secondary break-up models, thanks to a validation of the computed results against experimental data available for the ECN Spray G baseline condition. Specifically, attention was focused on spray penetration along with an analysis of spray morphology and effects of plume-to-plume interaction. Afterwards, the reference set-up was tested and validated under different operating conditions, characterized by detailed experimental measurements specifically provided for this work. In particular, Mie scattering and Schlieren techniques allowed the quasi-simultaneous acquisition of both vapor and liquid penetrations, while a customized image-processing procedure, developed in Matlab environment, was used for the outline of the spray contours of both fuel phases to measure the parameters characterizing the jet development. A robust reference numerical set-up was identified, capable to reproduce with good accuracy the injection process of a multi-hole GDI spray under the wide range of tested operating conditions

Sant’Ambrogio e la sua età

"Non sorprende che per l'Expo Milano 2015 venga ripubblicato il volume di Angelo Paredi 'Sant'Ambrogio e la sua età', apparso in terza edizione ampliata e aggiornata nel 1994, dopo la prima del 1940. A raccomandare il volume è, anzitutto, la figura a cui è dedicato, ossia il vescovo sant'Ambrogio, simbolo di Milano, del suo spirito, della sua storia e della sua cultura. Ma a motivare la riedizione concorre indubbiamente anche il valore dell'opera di Paredi, del quale rappresenta il capolavoro e che è divenuta un classico nella bibliografia santambrosiana [...]. Sant'Ambrogio è collocato da Paredi dentro un ampio e analitico contesto storico; tuttavia, assai più di quello che possa sembrare a una prima impressione, Ambrogio traspare anche irresistibilmente, da cenni sobri ma penetranti e compiacenti, nella sua interiorità, pur se non sono taciuti alcuni limiti. Non si possono leggere, per esempio, senza restare avvinti i capitoli su: Le vergini, La sua parola, La conquista più bella, Musica e poesia, e il capitolo finale, Il santo, che, riassumendo la figura di Ambrogio, la imprime indelebilmente nel lettore

Stakeholder interactions as sources for organisational learning: insights from the water sector

Purpose - This paper aims to understand stakeholders' sentiments with respect to company policies in the water utilities (WU) sector and to explore if and how these sentiments could be a source for organisational learning. Design/methodology/approach - This study investigates the use of social media in WUs’ and stakeholders’ reactions as a source of data for organisational learning. This paper relies on a mixed-methods approach based on sentiment analysis of Facebook (FB) pages and semi-structured interviews with sustainability managers from a sample of Italian WUs. Findings - Findings show that WUs increasingly use FB mainly to promote and disclose environmental issues and as a source of information for organisational learning. A longitudinal analysis of environmental disclosure via FB reveals a growing trend of both companies’ posts and stakeholder interactions and significant differences among organisations in their ways of using information and knowledge obtained from social media. Originality/value - Theoretically, this paper builds an original link between disclosure via social media and organisational learning processes. Empirically, to the best of the authors’ knowledge, this is one of the first studies to identify the quantity and quality of environmental disclosure via FB and the related stakeholders’ reactions

Cooperatives and economic balance

From the corporate point of view, the cooperative company is most likely one of the most complex types of companies in the current regulatory landscape. It is characterized by specific objectives that go hand in hand with those of for-profit companies, and yet don’t replace them. The pursuit of economic results and consistent patrimonial and financial balances are in fact fundamental objectives, however they are preparatory to the achievement of the main purpose of the cooperative: the mutuality or in the case of social cooperatives, the achievement of social goals (Giacomini, Chiaf & Mazzoleni, 2016)

Cooperatives and economic balance

From the corporate point of view, the cooperative company is most likely one of the most complex types of companies in the current regulatory landscape. It is characterized by specific objectives that go hand in hand with those of for-profit companies, and yet don’t replace them. The pursuit of economic results and consistent patrimonial and financial balances are in fact fundamental objectives, however they are preparatory to the achievement of the main purpose of the cooperative: the mutuality or in the case of social cooperatives, the achievement of social goals (Giacomini, Chiaf & Mazzoleni, 2016)

Environmental disclosure and stakeholder engagement via social media: state of the art and potential in public utilities

The concept of sustainable development has become dominant in the current socio-economic debate at the global level. In particular, environmental issues have become increasingly central in the action of all organisations: private, public and hybrid. Analysing a sample of Italian public utilities, we studied the level of disclosure regarding environmental topics via public Facebook pages. The aim of this study is to evaluate the impact of Web 2.0 on municipally owned public utilities’ voluntary disclosure of environmental issues and stakeholder interest in this field. The findings show that the use of Facebook by public utilities to disclose environmental issues is still at an early stage. However, it is constantly growing, especially in the larger companies and in those with mixed public/private ownership

Environmental disclosure and stakeholder engagement via social media: state of the art and potential in public utilities

The concept of sustainable development has become dominant in the current socio-economic debate at the global level. In particular, environmental issues have become increasingly central in the action of all organisations: private, public and hybrid. Analysing a sample of Italian public utilities, we studied the level of disclosure regarding environmental topics via public Facebook pages. The aim of this study is to evaluate the impact of Web 2.0 on municipally owned public utilities’ voluntary disclosure of environmental issues and stakeholder interest in this field. The findings show that the use of Facebook by public utilities to disclose environmental issues is still at an early stage. However, it is constantly growing, especially in the larger companies and in those with mixed public/private ownership