This course aims at preparing students with an extensive know-how about the principles of operation of internal combustion engines, providing the skills required to develop and manage engineering projects involving selection, operation, design and optimization of IC engines.

Particular attention is paid to fluid dynamics, combustion, fuels and environmental aspects of IC engines in both transportation and off-highway sectors.

After completing the course students will be able to:

• define and evaluate all relevant parameters of an IC engine which define its architecture and operation;
• master the fundamental concepts of the gas exchange process and charge motions in engines and apply them for design and optimization purposes;
• assess the advantages of turbocharged versus natural aspirated engines and propose the best configuration depending on the field of application;
• define the requirements and suggest the preferred layout for the fuel injection system in SI and CI engines;
• describe the combustion in spark ignition and compression ignition engines and assess the influences of the most important operating parameters on the engine performance;
• know deeply the mechanisms of pollutant emission formation and in-cylinder and after-treatment solutions to reduce the environmental impact;
• have a good background in control of gas dynamic noise and select and/or design the optimal silencers for a given engine;
• demonstrate an understanding of challenges related to future technological developments from the fluid-dynamic, chemical and thermal point of view.

The course is organized in several modules which cover the different topics, whose study offer the students a complete knowledge about the design and operation of internal combustion engines:

Fundamentals of IC Engines
Fundamentals of IC engine thermodynamic cycles. Classification of IC engines. Performance indexes, engine maps.

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
Scavenging process in the two-stroke engine. Global scavenging parameters. Flow through the ports.

Turbocharging of IC Engines
Supercharging and turbochargers. Constant pressure and pulse turbocharging. Wastegate valves and variable geometry turbines. Dual stage turbocharging configurations.

Unsteady Flows in the Pipes
Effects of unsteady flows and pressure waves in the pipes on cylinder charging. Optimum design of the intake and exhaust pipe systems to exploit wave effect.

Fuels for IC 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.

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.

Innovative Powertrain Solutions
Innovative IC engines for eco-sustainable mobility: hybrid vehicles, alternative combustion modes.

Noise and Acoustics 
Noise source analysis and their control. Silencers, reactive and absorptive types.

Notions of thermodynamics, chemistry and fluid machines from the first level degree are required.

Evaluations at all exam dates will consist of:

• a first part with 10 multiple-choice questions on fundamental theoretical topics
• a second part with open theoretical and numerical questions
• a mandatory oral to complete the exam only for the highest marks (≥ 29)

Students have the possibility to take a mid-term exam, that allows the exemption of the first part of the course at the first official exam date only. Hence in this occasion, students who passed (mark ≥ 18/30) the mid-term exam will be able to choose between taking an exam on the second part of the course (both parts need to be sufficient, the mark will be an arithmetic average) or on the entire course, if they intend to refuse the evaluation they received in the mid-term. From the second official exam date, the mid-term results are not considered valid anymore, so that only the exam on the entire course is available.

The student during the examination must demonstrate:

• to have the ability to organize the knowledge of the different topics of the course and the interrelations existing between them;
• to have the capacity for critical reasoning on the theoretical concepts that led to the definition of the different technological solutions which have been studied;
• to be able to quantitatively determine the main geometrical and operational parameters which are asked in the proposed numerical exercises;
• to describe each topic with good technical language and adequate synthesis and linearity.