internal combustion engines

espandiInternal combustion engines

Codice identificativo insegnamento: 054364
Programma sintetico:tThe course aims to prepare students with an extensive know-how about principles of operation of internal combustion engines and to provide the skills required to develop and manage engineering projects involving selection, operation, design and optimization of i.c. engines. Particular attention is paid to fluid dynamics, combustion, energy and environmental aspects of engines used in both transportation and off-highway sectors.

Fundamentals of IC engine thermodynamic cycles.
Classification of IC engines. Performance indexes (thermal efficiency, fuel consumption, reliability, drivability), engine maps. Laboratory with hands on experience on engines.

Stationary and Nonroad engines
Classification and characteristics of stationary and nonroad engines. Thermal efficiency and development roadmap.

Gas Exchange Process
Inlet and exhaust processes in the four-stroke engine. Quasi-steady and dynamic effects on cylinder charging. Flow through the valves: flow rates and discharge coefficients. Valve flow areas, optimum lifts and timings. Two-stroke engines.

Fluid dynamic engine modelling
Hierarchy of computational models for engine simulation. Fundamental equations (1D) in conservative form. Numerical methods. Examples of application. Numerical laboratory of engine gas dynamics.

Turbocharging of IC Engines
Supercharging and turbochargers. Constant pressure and pulse turbocharging. Wastegate valves and variable geometry turbines. Dual stage turbocharging configurations. Requirements for powertrain and transient response of the turbocharger.

Unsteady Flows in the Pipes
Effects of unsteady flows and pressure waves in the pipes. Optimum design of the intake and exhaust pipe systems to exploit wave effects Numerical laboratory of engine gas dynamics

Fuels for engines
Properties of conventional (gasoline, diesel) and alternative fuels (bio-ethanol, biodiesel, gaseous fuels, synthetic fuels). Knock rating of fuels.

Injection Systems for SI and Diesel engines
Fuel injection systems for SI and Diesel engines. Spray atomization and penetration. Common rail systems.

In-Cylinder Turbulent Flow
Turbulent air motion: swirl, squish and tumble.

Ignition systems for SI engines
Fundamental of ignition systems for SI engines. Spark plugs characteristics. Turbulent jet ignition.

Combustion in SI Engines
Normal and abnormal combustion processes in spark ignition engines.

Combustion in CI Engines
Non-premixed combustion, flame structure, ignition delay. Innovative low temperature combustion modes.

Emission Formation
Pollutant formation mechanisms and emission control strategies. Aftertreatment systems: three-way catalyst, Diesel particulate filter, Selective Catalytic Reduction catalyst with urea injection. Vehicle Exhaust Emission Testing Procedures.

Innovative Powertrain Solutions
Innovative IC engines for eco-sustainable mobility: integration in mild and full hybrid vehicles, alternative combustion modes.