Articoli scientifici (Scientific paper) by Fabrizio Mazzetto
Fuel, 2021
The partial replacement of conventional fuels with “bio-based” fuels represents a viable energy s... more The partial replacement of conventional fuels with “bio-based” fuels represents a viable energy strategy for cleaner distributed-power generation (agricultural/co-generative units). Although internal combustion engines represent a well-established technology, they will continue to play a crucial role in this energy revolution thanks to their flexibility of use and reliability. Considering compression-ignition engines, the fuel change is simple and requires no modification. Yet some critical issues related to different fuel viscosity may arise. The aim of this study is, therefore, to investigate with a mixed experimental–numerical approach: (a) the kinematic viscosity of many fuel blends (diesel oil-biodiesel-bioethanol) at the standard temperatures of 40 °C and 100 °C, and (b) the effects of the fuel viscosity on engine performance. The data and the mathematical model obtained through the Response Surface Methodology allowed observing that: (a) the fuel-feed system should include a preheater to obtain the same fuel viscosity in blends as in pump diesel oil and avoid issues in the fuel feed; (b) the viscosity at 40 °C progressively increases by 38% (from 3.03 to 4.18 mm2 s−1) as the biodiesel percentage in the blend spans from 0 to 100%; (c) bioethanol fluidizes the blends, reducing the viscosity by about 2% per percentage point of bioethanol in the blend. Also, some trials on a farm tractor fuelled with some of these blends allowed to identify that ternary blends with a viscosity > 3.33 mm2 s−1, whatever the composition within the validity ranges of models (0 ≤ biodiesel ≤ 100, 0 ≤ bioethanol ≤ 3), give rise to the maximum torque increment.
Applied Sciences, 2020
Featured Application: This study describes the possible outputs of a novel test rig having an inc... more Featured Application: This study describes the possible outputs of a novel test rig having an inclinable and rotating turntable, illustrating in detail the physical laws governing the phenomena. This rig can be successfully used to test the stability of real-scale vehicles in many operative conditions. Abstract: The stability of agricultural machines, earth-moving machines, snow-compaction machines and, in general, of all vehicles that may operate on sloping terrains is a very important technical feature and should not be underestimated. In fact, it is correlated, above all, to the safety of the operators, but also to the preservation of the structural integrity of these vehicles, to the prosecution of the activities and to the preservation of the economic investment. Although these facts are well-known, the international legislation and technical standards do not yet have a sufficient level of detail to give an all-inclusive quantification of the stability of the vehicle under examination in all its working conditions, e.g., at different inclination angles of the support surface, at different climbing angles of the vehicle on the slope, with different tires and inflating pressures, and on different terrains. Actual standards limit the stability tests to the experimental measurement of the lateral rollover angle only. Furthermore, the realization of unconventional test equipment able to widen the usually-tested scenarios could not be simple, due to the necessary size that such equipment should have (to perform tests not in scale) and to the related difficulties of handling full-scale vehicles. This work illustrates the applications of a new rig for testing the stability of vehicles, able to address all the above-illustrated issues and of possible future adoption to certify the stability performance of machines and perform homologations. This installation, named "rotating platform" or "turntable", has the peculiarity of being able to move the machine positioned on it according to two rotational degrees of freedom: (1) overall inclination of the support plane, (2) rotation of the support plane around an axis perpendicular to the plane. The same installation is also designed to record the weight supported by each wheel of the machine placed on it (by means of four sensorized quadrants), both when the platform is motionless and while the above-described movements of tilt and rotation are being carried out, thus locating precisely the spatial position of the vehicle center of gravity. The presented physical-mathematical models highlight the great potential of this facility, anticipate the outcomes of the recordings that the experimenters will have at disposal when the test rig will be effectively active, and help the future understanding of trends of data, thus maximizing the available information content.
International Journal of Safety and Security Engineering, 2020
A problem that is common in agriculture but not very publicized, thanks to the absence of victims... more A problem that is common in agriculture but not very publicized, thanks to the absence of victims, is the rollover of Centre Pivot and Lateral Move irrigation systems. These accidents are due to particularly-strong winds acting on the spans, and they are potentially very destructive for the installations. Also, the restoration phase of the installations requires always an intervention of lifting of the machinery on the field, with a potential further damage to crops (setting) and land (compaction). Given the basic inevitability of the phenomenon, due to atmospheric events, these rollovers could be however limited e.g. by proposing a system design granting a higher stability. Therefore, we have firstly modelled the rollover dynamics of these systems, considering the geometry, the masses, the forces acting on them (wind, gravity), the position of the centre of gravity. Then, thanks to morphometry, we have investigated booms’ stability as a consequence of a proportional or not-proportional alteration of the system sizes, in particular: the upscaling of supports, done by some manufacturers, and the lengthening of spans, often required by customers. Morphometry is a method born in biology, typically used to describe and analyse statistically the shape variations within and among samples of organisms as a result of growth, experimental treatments or evolution. As the idea of evolutionary adaptation is intrinsic in the technical evolution of human-made systems (models, variants) operated by manufacturers, also artificial systems can be studied or improved via the morphometry, as operated here. The output of this study is a physical model of rollover and a sensitivity analysis of a reference configuration for an irrigation boom. Thanks to these analyses, we were able to demonstrate, for example, how a scaling-up of boom supports, respectful of geometric ratios, can increase the system stability despite the elevation of the pressure point of the wind on the frame.
Energy Procedia, Feb 2019
The fuelling of internal combustion engines with biofuels has certainly many environmental and en... more The fuelling of internal combustion engines with biofuels has certainly many environmental and energetic advantages. These advantages are particularly effective in the agricultural sector, where an integrated biofuel supply-chain would further benefit the overall carbon balance. Unfortunately, there are also some drawbacks, mainly concerning the engine performances (lowering of the torque curve), but also environmental (possible raising of the NOx emissions). However, by appropriately mixing two biofuels with known opposite effects on the combustion process, it is theoretically possible to compensate the aforementioned disadvantages. In this work, some experiments were carried out in this direction by fuelling a farm tractor with four different fuel mixes; the collected data were processed through the Response Surface Methodology to obtain multi-parameter regression equations useful to identify the optimal fuel mixtures composition. Thanks to this approach, it was found that biodiesel has a positive effect on the torque, while the addition of bioethanol has a much bigger detrimental effect; on the contrary, bioethanol should be added to a mixture with a minimum of 8-12 % of biodiesel to get advantages in terms of NOx concentration reduction.
Using agricultural machines on slopes is very risky for operators: drivers difficultly have a cor... more Using agricultural machines on slopes is very risky for operators: drivers difficultly have a correct perception of the stability-condition of their vehicles when travelling, especially because it is impossible to instantly check the ground elevation and harshness in correspondence of each wheel. Moreover, the tests that are usually performed to characterize these machines’ stability are scarcely helpful in real conditions: these tests check the lateral overturning (maximum angle) in two static configurations only. Evidently, these do not cover most of real situations, do not locate its centre-of-mass and do not consider the centrifugal force (causing load-transfers and dynamically-variable readjustments of the machine’s trim in turnings), thus making impossible the setup of eventual active/passive safety-systems to be installed on vehicles.
Therefore, with the aim of overcoming the limitations of actual tests, giving a higher level of information to the tractors’ manufacturers and users, we have conceived a completely-new test-apparatus to be installed within our laboratory: the Tiltable Platform. It integrates two subsystems, illustrated hereinafter.
(1) The tiltable/angleable plane is a wide flat structure (15×15 m), able to simulate different ground-gradients, allowing a vehicle to manoeuvre/travel on it along circular paths in a controlled and safe environment. It can also generate an angle at half of its width, transversal to the maximum-slope direction (simulating the exits from interrows).
(2) The tilting turntable: has a circular shape and is divided into quadrants, each capable of measuring the weight sustained due to a motionless vehicle positioned on them; it is installed on a tilting structure and can rotate around a vertical axis, thus allowing to vary the angular position of the vehicle’s longitudinal axis with reference to the maximum-slope direction.
Finally, this test-rig will be useful to develop new test-methodologies to certify the agricultural machines’ stability in real operating-conditions (e.g. operating with ballast/mounted-implements).
Papers by Fabrizio Mazzetto
Il Progettista industriale, 2018
Prima di parlare di efficienza delle macchine agricole è necessario fare un po’ di chiarezza sui ... more Prima di parlare di efficienza delle macchine agricole è necessario fare un po’ di chiarezza sui termini. Quando si parla di quantificazione dell’efficienza di un sistema si intende il calcolo del suo rendimento, inteso come il rapporto matematico tra l’energia utile in uscita al sistema considerato (in qualunque forma essa sia: elettrica, chimica, termica, …) e l’energia in entrata (ancora una volta, in qualunque forma essa sia), espresso con un numero puro (tra 0 e 1) oppure come percentuale. La quantificazione del rendimento non è un’operazione semplice, perché implica un controllo molto preciso dei flussi di energia che attraversano la frontiera del sistema considerato ma è sempre utile, poiché è associata alla bontà delle trasformazioni energetiche che avvengono all’interno del sistema. L’operazione di contabilizzazione del rendimento di un sistema ha un altro risvolto molto interessante, che riguarda la quantificazione della quota parte dell’energia in ingresso che viene dissipata all’interno del sistema sotto forma di calore, e che quindi è fonte di dilatazioni strutturali e possibili surriscaldamenti anche a carico dei sistemi adiacenti.
An eddy-current brake, capable of measuring the torque and the power of internal combustion engin... more An eddy-current brake, capable of measuring the torque and the power of internal combustion engines at desired rotational speeds, has been fully interfaced with an external NI cDAQ 9178 data logger. Thanks to this system, it is possible to collect and synchronize the data coming from the test stand and from several other sensors equipping the motors under test: a load cell used in a chrono-gravimetric fuel consumption system, many thermocouples, a lambda probe, an exhaust gas analyser. To have a better control of the position of the throttling valve during the trials (hence a higher repeatability), a control system, based on an Arduino board, directly acts on the valve through a servomotor. Then, a series of software tools allows the interfacing of the various devices and the automatic post-processing of the acquired data (filtering of signals, recognition of data corresponding to the single engine speeds, time-averaging). The described testing equipment and the implemented procedur...
L'ingegneria agraria …, 2005
... Fabrizio Mazzetto, Aldo Calcante. - In: L'ingegneria agraria per lo sviluppo sostenibile... more ... Fabrizio Mazzetto, Aldo Calcante. - In: L'ingegneria agraria per lo sviluppo sostenibile dell'area mediterranea / G. Blandini, R. Manetto. - Catania : GeoGrafica, 2005. - ISBN 8890186003. ((Intervento presentato al 8. Convegno Nazionale AIIA, Catania (27-30 giugno), 2005. ...
… different scales of …, 2009
Integrated evaluation of N and energy use, economic performance and weed control / M. Fumagalli, ... more Integrated evaluation of N and energy use, economic performance and weed control / M. Fumagalli, L. Bechini, F. Mazzetto, P. Sacco, F. Vidotto, G. Sali, C. Bulgheroni, M. Pastori, M. Acutis - In: Connecting different scales of nitrogen use in agriculture : proceedings of the ...
20th International Scientific Conference Engineering for Rural Development Proceedings, 2021
In un momento come quello attuale, dove è importante razionalizzare gli investimenti, un’attenta ... more In un momento come quello attuale, dove è importante razionalizzare gli investimenti, un’attenta analisi dei costi di esercizio del parco macchine rappresenta un valido supporto nell’ottimizzazione dei costi aziendali. In questo quadro i costi di manutenzione e riparazione (Cmr) incidono generalmente sul 10-15% dei costi totali e tendono ad aumentare con l’età della macchina diventando un importante parametro riguardo al periodo ottimale per la sostituzione della macchina stessa. I modelli di stima dei Cmr attualmente in vigore sono, nella quasi totalità, calibrati in funzione del comparto agricolo statunitense, estremamente differente rispetto a quello italiano. Di conseguenza, può essere interessante riesaminare i parametri di modello in base alle caratteristiche nazionali; a tale scopo, nel presente lavoro sono stati acquisiti i dati riguardanti i Cmr di vari modelli di trattori 4RM presenti in Pianura Padana. L’analisi condotta ha evidenziato la necessità di aggiornare il modell...
The Response Surface Methodology (RSM) is used here to analyse a large set of experimental data r... more The Response Surface Methodology (RSM) is used here to analyse a large set of experimental data regarding the mechanical and environmental performances of an internal combustion engine (ICE) used to power a farm tractor. The aim is twofold: (i) to demonstrate the effectiveness of RSM in quantitatively assessing the effects of biofuels on a complex system like an ICE; (ii) to supply the users with easy-to-use models to predict the effect of biofuel blends on performance and emissions of tractor engines and find an optimal blend according to given user-defined parameters. The methodology showed good prediction abilities: the calculated average errors for the first models were lower than 0.38 and 1.40% on 6 test cases, with a higher accuracy in the assessment of the ICE mechanical performance. As a result, two effective and user-friendly models for torque and NOx emissions were developed; they were subsequently used to single out some fuel blends having interesting effects in terms of ...
Fuel, 2021
Abstract • The partial replacement of conventional fuels with “bio-based” fuels represents a viab... more Abstract • The partial replacement of conventional fuels with “bio-based” fuels represents a viable energy strategy for cleaner distributed-power generation (agricultural/co-generative units). Although internal combustion engines represent a well-established technology, they will continue to play a crucial role in this energy revolution thanks to their flexibility of use and reliability. Considering compression-ignition engines, the fuel change is simple and requires no modification. Yet some critical issues related to different fuel viscosity may arise. The aim of this study is, therefore, to investigate with a mixed experimental–numerical approach: (a) the kinematic viscosity of many fuel blends (diesel oil-biodiesel-bioethanol) at the standard temperatures of 40 °C and 100 °C, and (b) the effects of the fuel viscosity on engine performance. The data and the mathematical model obtained through the Response Surface Methodology allowed observing that: (a) the fuel-feed system should include a preheater to obtain the same fuel viscosity in blends as in pump diesel oil and avoid issues in the fuel feed; (b) the viscosity at 40 °C progressively increases by 38% (from 3.03 to 4.18 mm2 s−1) as the biodiesel percentage in the blend spans from 0 to 100%; (c) bioethanol fluidizes the blends, reducing the viscosity by about 2% per percentage point of bioethanol in the blend. Also, some trials on a farm tractor fuelled with some of these blends allowed to identify that ternary blends with a viscosity > 3.33 mm2 s−1, whatever the composition within the validity ranges of models (0 ≤ biodiesel ≤ 100, 0 ≤ bioethanol ≤ 3), give rise to the maximum torque increment.
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Articoli scientifici (Scientific paper) by Fabrizio Mazzetto
Therefore, with the aim of overcoming the limitations of actual tests, giving a higher level of information to the tractors’ manufacturers and users, we have conceived a completely-new test-apparatus to be installed within our laboratory: the Tiltable Platform. It integrates two subsystems, illustrated hereinafter.
(1) The tiltable/angleable plane is a wide flat structure (15×15 m), able to simulate different ground-gradients, allowing a vehicle to manoeuvre/travel on it along circular paths in a controlled and safe environment. It can also generate an angle at half of its width, transversal to the maximum-slope direction (simulating the exits from interrows).
(2) The tilting turntable: has a circular shape and is divided into quadrants, each capable of measuring the weight sustained due to a motionless vehicle positioned on them; it is installed on a tilting structure and can rotate around a vertical axis, thus allowing to vary the angular position of the vehicle’s longitudinal axis with reference to the maximum-slope direction.
Finally, this test-rig will be useful to develop new test-methodologies to certify the agricultural machines’ stability in real operating-conditions (e.g. operating with ballast/mounted-implements).
Papers by Fabrizio Mazzetto
Therefore, with the aim of overcoming the limitations of actual tests, giving a higher level of information to the tractors’ manufacturers and users, we have conceived a completely-new test-apparatus to be installed within our laboratory: the Tiltable Platform. It integrates two subsystems, illustrated hereinafter.
(1) The tiltable/angleable plane is a wide flat structure (15×15 m), able to simulate different ground-gradients, allowing a vehicle to manoeuvre/travel on it along circular paths in a controlled and safe environment. It can also generate an angle at half of its width, transversal to the maximum-slope direction (simulating the exits from interrows).
(2) The tilting turntable: has a circular shape and is divided into quadrants, each capable of measuring the weight sustained due to a motionless vehicle positioned on them; it is installed on a tilting structure and can rotate around a vertical axis, thus allowing to vary the angular position of the vehicle’s longitudinal axis with reference to the maximum-slope direction.
Finally, this test-rig will be useful to develop new test-methodologies to certify the agricultural machines’ stability in real operating-conditions (e.g. operating with ballast/mounted-implements).