57951 - Hydraulic Machines and Internal Combustion Engines

Learning outcomes

Focus of the course is to give to students basic notions regarding:

1. internal combustion engines and their control;

2. centrifugal and volumetric pumps: basics, installation and control.

Basic requested knowledges are: General Physics L, Technical physics L, Machines  L,  Mechanical and thermical measures L.

Course contents

Internal combustion engines:

Introduction to internal combustion engines: main definitions. Theoretical and actual engine cycles: Otto, Diesel, Sabathè and their governing equations. Actual indicating diagram and t-S diagram: indicating efficiency and Sabathè efficiency. Engine power thermal expression. Thermal tonality. Exhaust gas mean temperature computation. Indicatine and effective mean pressare. Power and torque curves and expressions. Meaning of the ratio stroke/bore. Splitting of the swept volume for the same power or the same swept volume. Engine framework and balancing of the first and second order inertial forces. Combustion process in gasoline and Diesel engines. Basics of: combustion velocity, flame front, equivalence ratio, autoignition delay, stechiometric ratio, detonation. Timing system: basics and architecture. Strokes diagram. Carburetor: basics. Gasoline and Diesel engines governing. Direct and in direct injection: framework. Common Rail injection systems: critical issues, potentiality and lay-out. Raw emissions: formation and limitino techniques. Cooling systems by air, water and for oil. Dimensioning criteria for car radiator. Turbocharging by mean volumetric and centrifugal compressor: equations. Two strokes engine. Engine control strategies.

Idraulic operating machines:

 

Idraulic operatine machines: basic equations. Mono-dimesnional theory and Eulero equations: validity fields.

Centrifugal pumps: lay-out and basics. Velocity triangles drawing.  Pump head expression as a function of the volumetric flow rate: theoretical and actual expression. Volute basic design. Characteristic index and hill diagrams. Pumps framework depending on the volumetric flow rate. Centrifugal pump installation: critical issues. Cavitation onset and formation: NPSH definition and its meaning. Limit NPSH and system NPSH. NPSH determination in the system: system lay-out. Axial pumps. Pluri-cellullar pumps for high heads.

Volumetric pumps: lay-out and basics.

Aerospatial propulsion: basics.

Readings/Bibliography

[1] G.Minelli, Motori endotermici alternativi, Ed. Pitagora

[2] G. Ferrari, Motori a combustione interna, Ed. Il Capitello

[3] G.Minelli, Macchine idrauliche, Ed. Pitagora

[3] G.Minelli, Turbine a gas, Ed. Pitagora

[4] G. Cantore, Macchine, Ed. Leonardo

Teaching methods

Course is structured into two main fields:
a. frontal lessons
b. seminars

Assessment methods

Oral test on the whole program.

Office hours

See the website of Piero Pelloni