|Politecnico di Torino|
|Academic Year 2014/15|
Design of engine and control system
Master of science-level of the Bologna process in Automotive Engineering - Torino
The module aims at providing students, who have chosen the 'Engine' option, with basic knowledge regarding the design of the engine and of its control system, with particular reference to thermo-fluid dynamic and combustion aspects in relation to its structural design, by studying in particular:
-the engine architecture and thermal-structural features of its main components;
-systems for gas exchange processes, fuel metering and air flow control;
-fuel injection systems, spray processes and their control;
-basic thermo-fluid dynamics aspects governing the combustion process and chamber design.
Expected learning outcomes
A wide knowledge of the various aspects and methodologies that are involved in the design and control of an engine and its components, with reference to operational, thermo-fluid dynamic and structural aspects. Capability of evaluating and optimizing the variables that condition the charge exchange processes (including induction system variable-geometry tuning), the distribution (also with reference to variable valve timing and actuation). Familiarity with: fuel injection and injection systems; in-engine fluid dynamics and combustion, their interaction and influence on fuel consumption and pollutant emissions; innovative combustion strategies and systems. Capability of analyzing thermo-fluid dynamic and combustion processes by means of zerodimensional and multidimensional numerical models.
Prerequisites / Assumed knowledge
A good knowledge of engine architecture as well as operating and control features .
Engine architecture and thermo-structural design
-Engine architecture: in-depth analysis of some significant engine layouts. Criteria for selecting optimal working design parameters and configurations. Based on engine mission and design requirements, evaluation will be carried out of: engine working cycle, structural configuration (displacement, cylinder layout, stroke to bore ratio, crank-shaft features); dynamics and vibrational analysis; bearings selection.
-Distribution system analysis: valve command devices and their effect on the engine mechanical efficiency (criteria for minimizing friction); wearing down at the cam-follower contact; examples of CAE support techniques.
-Temperature fields and thermal load modeling and evaluation of in-engine components: heat transfer processes in engines; average heat flux calculation; operating condition effects; calculation models for instantaneous thermal flux.
-Criteria for static engine component design: main effects of production, assembly and working features of engine components on mechanical and thermal stresses; deformation analysis criteria; cooling air casing; review of FEM analysis and applications.
-Lubrication system analysis: lubricants; circuit layout and shaping; CAE support techniques.
Thermo-fluid dynamic design of charge exchange system and air flow control
-Valve flow coefficients and their measurement; kinematic and dynamic aspects of distribution and their influence on engine volumetric efficiency; valve lift and timing assessment.
-Gas dynamics of nonstationary flows: numerical analysis of wave propagation phenomena in intake and exhaust systems aimed at their optimization for improved engine performance.
-Onedimensional and multidimensional calculation methods (layout design and detail optimisation).
-Variable Valve Timing (VVT) and Variable Valve Actuation (VVA): valve lift and timing effects on volumetric efficiency, engine torque and on residual gas mass fraction; application of VVT and VVA to SI and CI engines in order to improve their fuel conversion efficiency at different loads.
-Supercharging and turbocharging: methods of power boosting; engine driven compressors and turbochargers with exhaust gas turbines; constant-pressure turbocharging and pulse turbocharging; matching compressor turbine wheel and engine for optimum efficiency; intercooler system. Numerical models and simulation of turbocharger and boosted engine performance. Control strategies. Evaluation of the discharge backpressure effects on engine performance. Systems with high boosting levels.
Fuel-feeding system design and control
-Review of liquid and gaseous fuels : conventional (reformulation), oxygenated and alternative fuels.
-Models for numerical analysis of fuel injection system performance and control. Transient flow simulation including possible instability and cavitation occurrence; effects on the spray formation.
-Spray interaction with air motion: mixture formation mechanisms and their effects on engine performance.
- Gasoline injection: manifold single-point and multipoint injection; in-cylinder direct gasoline injection (GDI). Strategies for direct fuel injection: homogeneous and stratified charge formation.
-Diesel injection: Common Rail systems, Unit Injector systems; fundamentals for their design.
-Systems for gaseous fuel injection.
Thermo-fluid dynamic aspects of combustion-system design and control
Combustion processes in SI engines
-Measurement and analysis of in-cylinder pressure; heat release analysis, zero-dimensional models, multizone models and their application to combustion diagnostics and to engine design. Evaluation of the main combustion parameters.
-Ignition process, flame development and propagation; turbulence role in the combustion process; interaction between fluid dynamics and combustion; combustion parameter control; multidimensional simulation codes and their application to the combustion system design; principal combustion models and their limitations.
-Fuel direct injection and charge stratification process: different combustion strategies (stoichiometric combustion, homogeneous lean combustion and stratified lean combustion) and related control techniques.
Combustion processes in CI engines
-Generation of mean motion and turbulence and control of these in relation to their effects on performance and polluting emissions, with particular reference to particulate matter; spray and mixture formation.
-Physical-chemical ignition delay; evolution of the combustion process; combustion noise and anomalies. Heat-release analysis. Effects of multiple injections and of their temporal distribution on heat release and on engine performance. Engine downsizing.
-Thermo-fluid dynamic designing by zerodimensional ('filling and emptying') onedimensional and multidimensional models.
Students have the opportunity to apply concepts learnt during lectures. Calculations on the computer will be carried out using zerodimensional, onedimensional and multidimensional codes for engine-like processes.
Students can also carry out laboratory work on pressure measurement in the combustion chamber of gasoline and natural gas engines and its heat-release analysis. There is also the opportunity for students to carry out tests at the injector test bench in order to analyze injection parameters in common rail systems.
Texts, readings, handouts and other learning resources
Didactic material such as notes diagrams and tables used during lectures and practical work are all collected in hard copy or CD-ROM which will be available to students. The following is a list of references for further study.
-G. Ferrari: 'Motori a combustione interna', Il Capitello, Torino, 2001.
-D.E. Winterborne, R.J. Pearson: 'Design Techniques for Engine Manifolds', SAE Int. Publisher, 1999.
-H. Bauer, K.H. Dietsche, J. Crepin, F. Dinkler: 'Diesel-Engine Management', Bosch-SAE Publishers, 1999.
-G. Bocchi: 'Motori a quattro tempi', Hoepli, Milano, 1997.
-W.H. Crouse, D.L. Anglin: 'Automotive Engines' MacMillan/McGraw-Hill, N.Y., 1995.
-A. Garro: 'Progettazione Strutturale del Motore', Levrotto & Bella, Torino, 1992
-J.B. Heywood: 'Internal combustion engines fundamentals', McGraw-Hill, N.Y., 1988.
-U. Adler, H. Bauer: 'Automotive Electric/Electronic Systems', Bosch-SAE Publishers, 1988.
-V.I. Krutov: 'Automatic Control of Internal Combustion Engines', Mir Publishers, Moscow, 1987.
-C.R. Ferguson: 'Internal Combustion Engines', John Wiley & Sons, NY, 1986.
-C.F. Taylor: 'The Internal Combustion Engine in Theory and Practice', The M.I.T. Press, Cambridge, MA, 1985.
-H. List, A. Pischinger: 'Die Verbrennungskraftmaschine', 6 vol., Springer-Verlag, N.Y., 1976.
-R. Bussien: ' Automobiltechnisches Handbuch', Technischer Verlag, Berlin, 1965.
Assessment and grading criteria
Examination is based on the evaluation of practical work and on two exams at the end of each emisemester with exemption value. The oral examination is optional and essentially for those who have not completed at least 80% of the practical work and have not obtained the exemptions at the end of each submodule.
Programma definitivo per l'A.A.2014/15