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 sizing. Basic concepts for the development of control strategies of automatic transmissions are also introduced.

The expected skills after the attendance of the course will be the knowledge of issues and methods in design/verification of engine main components and transmission main components, as well as the methodologies essential to the development of control strategies of some transmission systems. The expected learning outcomes for the engine part are the capabilities to: • compute the most important forces and moments acting on engine components (action due to gasses, inertias, dynamic actions); • recognise and manage engine components architecture/function for defining the corresponding computational simplified models; • select the most appropriate material for engine components; • define the methodological steps for designing and/or verifying the engine components; • develop the computational formulas for designing and/or verifying the engine components; • explain and demonstrate the computational formulas for designing and/or verifying the engine components. The expected learning outcomes for the transmission part are the capabilities to: • understand and comment on a technical drawing of a transmission system; • recognise the type of transmission system, the components and justify specific design solutions; • compare different transmission layouts highlighting their pros and cons in terms of efficiency and vehicle dynamic performance; • apply computational methods for transmission component design; • motivate the choice of a specific component in a transmission system; • discuss the effect of component selection and its characteristics on the dynamic performance of the vehicle.

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

Engine part (27 h) • Crank mechanism (1 h): overview of centred and offset layout; Displacement, velocity and acceleration of the piston; Angular speed and acceleration of the connecting rod; • Forces on the crank mechanism (2 h): 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 (1 h): Shape and geometry; Materials; Design guidelines; Numerical analysis (FEA). • Connecting rod (3 h): Architecture and geometry; Materials; Load analysis; Design guidelines. • Crankshaft (7 h): Architecture and geometry; Design guidelines; Classical static analysis; Classical dynamic analysis; Numerical dynamic analysis (FEA-MBA). • Main bearings (2 h): Architecture and geometry; Classical analysis; Numerical analysis (FEA-MBA). • Piston (4 h): Architecture and geometry; Materials; Design guidelines; Numerical analysis (FEA); Piston Slap. • Cylinder head and block (3 h): Architecture and geometry; Cooling circuit; Head gasket, Head cover; Deck; Liners; Fastening of cylinder head and main caps Residual stresses; Design guidelines; Numerical analysis (FEA). • Oil pan (1 h): Function and examples; Optimization methodology. • Exhaust manifold (3 h): Design guidelines; Geometries and materials; Working conditions; Experimental tests on test bench; Life estimations with multi-axial damage models. Overview on thermo-mechanical fatigue, 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). • Transmission part (27 h) • Transmission functions and architectures (1,5 h): Automotive transmission characteristics (functions, requirements and constraints, specific characteristics and technology); Transmission evolution and current trends (overview); Transmission architectures; Transmission components. • Manual Transmissions (3 h): 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). • Components design and testing (3 h). 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 (3 h): Function; Mechanical description (simple and multiple synchronizers, gearshift process); Design criteria (geometric and functional). • Shifting mechanisms (1,5 h): Functions; Internal shifting mechanisms (specific functions, interlocking devices); External shifting mechanisms (specific functions, bar and cable mechanisms); Shifting mechanism attributes. • Start-up devices and torsional dampers for MT (3 h). Friction clutches: functions; components (disengagement mechanism, driven plate, torsional dampers integrated into the clutch driven disk, thrust bearing, wear compensation mechanism). Torsional dampers: single vs dual mass flywheel, torsional vibrations. Design criteria for friction clutches. • Start-up device for AT (3h): hydraulic clutch and torque converter. Torque converter: losses, speed triangles, angular momentum and torque on a bladed wheel, performance curves comparison (hydraulic clutch, TC, Trilok TC), matching torque curves (engine and TC), TC performance on a vehicle, lock-up clutch. • Differentials, final drives and transfer boxes (3 h): 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, geared vs clutch-pack differentials, ZF, Torsen, Trac Lok); Viscous coupling; Active differential (Haldex); Differential effect on vehicle dynamics. • Automatic transmissions (3 h): 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); • Dual Clutch Transmission (DCT) (3 h): Powershift concept; Double clutch units; DCT Mechanical layouts and components; Wet and Dry DCT; Examples of DCTs in production; Gearshift modeling and control; Power recirculation issue.

• Theory lessons (54 hours); • Practice classes on subjects presented at theory classes (26 hours). 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 and transmisson design process, tailored codes are 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. Possible additional deepening 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 • M. Guiggiani, The Science of Vehicle Dynamics, Springer, 2nd Edition • 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

Modalitΰ di esame: Prova orale obbligatoria; Elaborato progettuale in 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 the entire program of the course (one question on engine, one question on transmissions). Each element is separately evaluated (with a rating out of thirty) 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. In order to pass the exam, the grade of each part must be greater than eighteen. 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 disabilitΰ 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'Unitΰ Special Needs, al fine di permettere al/la docente la declinazione piω idonea in riferimento alla specifica tipologia di esame.