34957 - Internal Combustion Engines (2nd cycle)

Learning outcomes

The student learns the specific issues relating to the operation and modeling of internal combustion engines, both spark and compression ignition.

Course contents

MODULE ON FUEL SUPPLY SYSTEMS FOR ENGINES (PROF. VITTORIO RAVAGLIOLI)

Evaluation of the performance indexes for an Internal Combustion Engine (Cylinder volume of the crank-slider mechanism, Indicated Torque, Heat Release, MFB, …).

Model of the heat rejected through the cylinder walls.

Combustion in spark-ignition engines. Effect of the ignition advance on combustion and performance (umbrella curve) and abnormal combustions (knock and pre-ignition).

Combustion in compression-ignition engines.

Zero-dimensional combustion modelling: the Wiebe model.

Engine emissions and after-treatment systems.

Injection systems for spark-ignition engines. PFI and GDI systems, “fluid film” phenomenon and Aquino model.

Calculation/Modelling of the engine intake charge:

- Alpha-N systems

- Speed-density systems

Calculation of the flow rate through the throttle body.

Volumetric and Dynamic Supercharging in internal combustion engines.

 

MODULE ON ENGINE SIMULATION MODELS (PROF. DAVIDE MORO)

The simulation of internal combustion engines: development of a zero-dimensional thermodynamic simulator with Matlab and the reference architecture of the engine in its main volumes.

The mass and energy balance for an open system in non-stationary conditions in the time and angular domain and the logical sequence of their use.

Implementation of the evaluation of the flow rate between the different volumes of the engine.

Implementation of the combustion phase in spark ignition and diesel engines.

Analysis of the results obtained from the simulation model of a 4-cylinder spark ignition engine:

- analysis of the main parameters and quantities in a fixed operating point;

- analysis of the main parameters and quantities under transient load conditions;

- determination of umbrella curves;

- simulation of the engine in all its operating range;

- comparison between spark ignition and diesel engines;

- influence of valve timing on engine performance.

Implementation of a real-time model of a reciprocating internal combustion engine: the dynamics of the intake manifold and the dynamics of the crankshaft-vehicle. Use of the Simulink toolbox for the development of the real-time model of the engine.

Considerations on the different ways of using simulation models: Software in the Loop systems, Hardware in the loop systems and Rapid Control Prototyping systems.

Implementation in the Simulink model of the spark ignition engine of the gasoline injection function based on the speed-density system and with the feed-back control of the lambda sensor to ensure the stoichiometry of the air/petrol ratio.

Readings/Bibliography

"Internal Combustion Engine Fundamentals", John B. Heywood, Mc Graw Hill

"Diesel-Engine Management", R. Bosch GmbH, Wiley

"Gasoline-Engine Management", R. Bosch GmbH, Wiley

"Vehicle Propulsion Systems: Introduction to Modeling and Optimization", L. Guzzella, A. Sciarretta, Springer

Teaching methods

The lessons are frontal in the classroom. The teacher, replacing the traditional blackboard, uses a tablet connected to the projector to develop the concepts and to show the supporting teaching material. At the end of the lesson the teacher makes available the material shown in a pdf file, downloadable from IOL platform.

Attendance is strongly recommended for better learning of concepts and notions, but does not affect the final evaluation process.

Assessment methods

The assessment methods consist of an oral part lasting about 45 minutes, during which the student must answer two questions, randomly extracted from a list of about eighty questions covering the entire program, list given at the last lesson of the course in the same dropbox folder that collects all the material presented during the lessons.

During the exam, with regard to internal combustion engines, their components and functions, is evaluated the student's ability to:

- use the thermodynamic instruments correctly;

- describe their operation;

- theoretically justify their architecture;

- represent their geometry with a free hand sketch;

- evaluate their performance;

The evaluation, expressed in thirtieths, will be higher the more the student is:

- autonomous in articulating responses to the two questions;

- exhaustive in explaining the arguments;

- precise in representing the functionality of the free-hand sketches.

The exam dates are comunicated in advance through the AlmaEsami web platform of the University of Bologna. It is possible to enroll to the exam from 7 to 2 days before the exam date. At the time of the exam the student must carry an identification document.

Teaching tools

In the course will be shown in detail the development of a zero-dimensional thermodynamic engine simulation code, from which a real time simulation code will be extracted and utilized for the description of the basic functions of injection control in an SI engine.

The projection from a laptop computer will be used for a description and analysis of results obtained by the models developed.

Office hours

See the website of Davide Moro

See the website of Vittorio Ravaglioli