Regarding the engine, the aim is to provide students the basic knowledge for the structural design, sizing and verification of main engine components by using analytical, semi-empirical and numerical approaches. Regarding the transmission, the goal is to provide students the basic knowledge for the design and application of transmissions, describing the architectural solutions and the main components, stating the methodologies used to proceed to their size. Basic concepts for development of control strategies of automatic transmissions are also introduced.

The skills acquired by students will be the knowledge of issues and methods in design engine main components and transmission main components, as well as the methodologies essential to the development of control strategies of some transmission systems.

To better understand the topics covered by the teaching, the basic knowledge and operative competence on materials mechanical behaviour, structural and applied mechanics, stress and strain states, and machine design are recommended.

Engine part Crank mechanism: Centred and offset layout; Displacement, velocity and acceleration of the piston; Angular speed and acceleration of the connecting rod; Forces on the crank mechanism; Reduction of the connecting rod; Reciprocating inertial force; Centrifugal inertial force; Resultant force on the crank mechanism; Forces on the connecting rod; Engine torque; Forces and moments on the cylinder block; Multi-cylinder engine and most stressed crank; Engine degree of irregularity. Wrist pin: Shape and geometry; Materials; Design guidelines; Numerical analysis (FEA). Connecting rod: Architecture and geometry; Materials; Load analysis; Design guidelines. Crankshaft: Architecture and geometry; Design guidelines; Classical static analysis; Classical dynamic analysis; Numerical dynamic analysis (FEA-MBA). Main bearings: Architecture and geometry; Classical analysis; Numerical analysis (FEA-MBA). Piston: Architecture and geometry; Materials; Design guidelines; Numerical analysis (FEA); Piston Slap. Cylinder head: Architecture and geometry; Cooling circuit; Head gasket, Head cover; Residual stresses; Design guidelines; Numerical analysis (FEA). Cylinder block: Architecture e geometry; Deck; Liners; Fastening of cylinder head and main caps; Residual stresses; Design guidelines; Numerical analysis (FEA). Oil pan: Function and examples; Optimization methodology. Thermo-mechanical fatigue: Introduction; Isothermal fatigue tests; Thermo-mechanical fatigue tests (TMF tests); TMF damage: mechanical fatigue, creep, oxidation; TMF residual life; Constitutive models for TMF; Damage models for TMF; General guidelines for numerical analysis (FEA). Exhaust manifold: Design guidelines; Geometries and materials; Working conditions; Experimental tests on test bench; Life estimations with multi-axial damage models. Transmission part Transmission functions and architectures: Automotive transmission characteristics (functions, requirements and constraints, specific characteristics and technology); Transmission evolution and current trends (overview); Transmission architectures; Transmission components. Gear ratios definition: Resistance to motion; Top bottom and intermediate gear ratios definition; Gear ratios influence on vehicle acceleration and fuel consumption. Manual Transmissions: Main configurations (forward speeds, reverse speed); Efficiency (power loss contributions, maps and measurement); Passenger cars layout schemes and practical examples (single, double and triple stage); Industrial vehicles layout schemes and practical examples (single and multiple range). Mission and components development process: Mission of vehicle and transmission (endurance, load profile); Assumptions and steps for a preliminary design; Product development steps. Components design and testing. Gears: Gear types; Endurance (fatigue phenomena, failures, damage accumulation); Noise (gear whine, gear rattle). Other components: Shafts; Bearings; Lubrication; Housings and seals. Testing technologies. Synchronizers: Function; Mechanical description (simple and multiple synchronizers, gearshift process); Design criteria (geometric and functional). Shifting mechanisms: Functions; Internal shifting mechanisms (specific functions, interlocking devices); External shifting mechanisms (specific functions, bar and cable mechanisms); Shifting mechanism attributes. Start-up devices. Friction clutches (for MT): Functions; Components (disengagement mechanism, driven plate, thrust bearing); Design criteria. Start-up devices for non-MT: General characteristics; Double clutch units; Hydraulic clutches and torque converters (schemes, equations, characteristic curves, performance on a vehicle, lock-up clutch). Differentials, final drives and transfer boxes: Differentials and final drives (rear and front wheel driven cars, industrial vehicles); All wheel drive transfer boxes (modified rear and front wheel drives); Differential theory outline (friction free differential, differential with internal friction); Self-locking differentials (definition, types, ZF, Torsen and Ferguson systems); Differential effect on vehicle dynamics. Shafts and joints: Shafts (propeller shafts, half shafts); Joints (universal and constant speed joints). Automatic transmissions: General issues (automation level, gearshift mode, stepped and continuously variable transmissions); Car transmissions with fixed rotation axis (with synchronizers, multi disc clutches, dual clutch); Car epicycloidal transmissions (simple and compound epicycloidal gear trains, production examples); Car CVTs (steel belt, rolling bodies); Industrial vehicles automatic transmissions (semi and full automatic transmissions); Control strategies (input/output parameters, speed selection for minimum consumption or comfort, speed choice in real driving conditions, brakes and clutches actuation). Transmissions historical evolution: Manual transmissions; Friction clutches; Automatic transmissions. Current transmissions overview and trends: Market and production trends; Technologies trends and comparison; Application on car segments; Future trends.

The practice consists of an engine and related gearbox design. Teachers provide the students with design constraints and requirements. The attending students will be randomly divided in to several groups. Each group will tackle a different design problem, two of them will be have the responsibility of the project. In particular, each group will design a component of an engine and the connected gearbox. The design process used for the main components of engine and gearbox has to implement the contents of lectures. To assist the engine design process, a tailored drawing code embedded in Siemens NX is provided. At the end of practices, students will present the results of their work to other groups and to the teachers. The aim of this kind of training is to involve the students into the actual process of powertrain design, facing the most important and relevant problems. In addition, students are encouraged to collaborate, to work in team and to be able to synthetize the obtained results.

Lectures subjects, text of practices as well as other didactic material are available on Corse Website. Reference textbooks for improving the study: - Makartchouk A., Diesel Engine Engineering, ISBN: 0-8247-0702-8, Marcel Dekker Inc., New York, NY, USA, 2002 - Hoag K.L., Vehicular engine design, ISBN: 0-7680-1661-4, SAE International, Warrendale, PA, USA, 2006 - Stone R., Introduction to internal combustion engines, ISBN 0-7680-0495-0, SAE International, Warrendale, PA, USA, 1999 - Taylor C.F., The internal-combustion engine in theory and practice, The M.I.T Press, Cambridge, UK, 1997 - G. Genta, L. Morello, The Automotive Chassis – vol. I and II, Springer, New York, 2009 - G. Lechner, H. Naunheimer, Automotive Transmissions, Fundamentals, Selection, Design and Application, Springer, Berlin, 1999 - J. Fenton, Handbook of Automotive Powertrain and Chassis Design, Professional Engineering Publishing, London, 1998 - By various authors, Design Practices: Passenger Car Automatic Transmissions, SAE, Warrendale (PA), 1994

Modalità di esame: Prova orale obbligatoria; Progetto di gruppo;

Exam: Compulsory oral exam; Group project;

... The exam is exclusively oral and it is constituted by the oral presentation the students made at the practice end and the oral discussion of two questions on both parts of the course (two questions on engine, two questions on transmissions). Each element is separately evaluated (with a rating in trentesimal value) and the overall score is defined by one third of the practice presentation, one third of the engine arguments and the remaining one third of the transmission arguments. The oral exam intends understanding the actual level of comprehension of all the course topics; schemes and formulas must be demonstrated and discussed and the methodological steps of topics development must be highlighted and explained. The exam lasts about 30 minutes.

Gli studenti e le studentesse con disabilità o con Disturbi Specifici di Apprendimento (DSA), oltre alla segnalazione tramite procedura informatizzata, sono invitati a comunicare anche direttamente al/la docente titolare dell'insegnamento, con un preavviso non inferiore ad una settimana dall'avvio della sessione d'esame, gli strumenti compensativi concordati con l'Unità Special Needs, al fine di permettere al/la docente la declinazione più idonea in riferimento alla specifica tipologia di esame.