85781 - Advanced Combustion Systems M

Course Unit Page

SDGs

This teaching activity contributes to the achievement of the Sustainable Development Goals of the UN 2030 Agenda.

Affordable and clean energy

Academic Year 2018/2019

Learning outcomes

The students will learn fundamental and practical concepts of the thermo-fluid dynamic design of premixed and non- premixed reciprocating engine combustion systems with a focus on the main fluid dynamics components behavior and design (Injectors, Intake/Exhaust Systems, Combustion Chamber, Exhaust Gas Aftertreatment). At the end of the course students will be able to apply the concepts learned to the conceptual and practical design of engine combustion systems, to run experimental campaign at bench and to address control strategy development.

Course contents

Spark Ignited Combustion System: laminar and turbulent flame speed, ignition and main combustion process. The knock and pre-ignition events. The combustion cycle-to-cycle variation. Effect of design parameters and operating conditions.

Compression Ignition non-premixed combustion: Spray dynamics and combustion chamber fluid dynamics characteristics, fuel auto-ignition, non-premixed combustion. Emission formation mechanisms.

Advanced Combustion systems based on auto-ignition of fully- or partially-premixed charge (HCCI,GDCI, RCCI): effect of fuel specifications and injection strategies. Rate of Heat release.

Criteria for the combustion chamber design including the definition of injector specifications and the optimizations of its interaction with in-cylinder flow characteristics (tumble-swirl).

In-cylinder charge motion: Swirl, Tumble, Squish motions. Swirl and Tumble dynamics and steady test bench characterization.

High-pressure direct-injection injection system (gasoline and Diesel engine). Injection system layout and operation. Multihole injector layout and operations. Injector characteristic curves. Injector nozzle flow fundamentals: cavitation and two-phase flow in injector holes.

Liquid jet atomization and spray breakup process: liquid jet break up process droplet break up.

Experimental characterization of fuel sprays: penetration, Sauter Mean Diameter, static flow rate.

Readings/Bibliography

Mandatory:

Lecturer note and presentation provided during the course in advance by uploading on the University dedicated web site Moodle.

Optional:

1. “Internal Combustion Engine Fundamentals”, J.B., Heywood, Mc Graw Hill.

2. SAE International Technical papers

Teaching methods

The course is given by teaching classes and students are encouraged to attend in order to improve the learning process and learning outcomes. Attending is not enforced and does not influence the final examination score.

The course includes: theoretical lectures made with the aid of multimedia systems. The didactic material is uploaded on the University website; training activities related to solve a practical combustion system design problem: students are grouped in teams of 4/6 people and asked to autonomously manage and develop a project to be presented and discussed during the exam.

Assessment methods

The exam includes oral test only.

The oral exam, for testing the understanding and application of the course content, consists of two questions and an oral speech of the project.

The examinations would check:

  1. Knowledge of thermofluid dynamic process

  2. Ability to cross correlate theory of physical processes and the final decision of the component and system specification in o order to accomplish a given combustion system target

  3. Ability to solve an actual design problem and deliver a technical report

The mimimum score is 18/30, the maximum is 30/30 with honours.

The minimum score is not achieved if large deficineces in learning outcomes are exhibited: i.e., missing main hypothesis, miss any knowledge of engine system, components and processes principles , etc.

Examinations schedule is available in advance on the University of Bologna web site AlmaEsami. Students willing to take the exam must join to the exam student list on the web site AlmaEsami.

Students are required to show their own ID before taking the exam

Teaching tools

The Course will be held by the use of:

- Slides and video projection

- CFD Simulation tool and automated optimization tool provided during the Course. The students will use them during project goal accomplishment.

Office hours

See the website of Gian Marco Bianchi