|Politecnico di Torino|
|Academic Year 2017/18|
Automotive internal combustion engines
Master of science-level of the Bologna process in Mechanical Engineering - Torino
Subject belonging to the "Ground-vehicles propulsion systems" branch.
It is addressed at providing the knowledge related to the functioning, operation and efficiency of internal combustion engines for ground vehicles propulsion, and the basic skills for their engineering and design from the Thermo-Fluid Dynamics viewpoint.
Expected learning outcomes
Deep knowledge of the features of functioning and efficiency of internal combustion engines for ground vehicles propulsion.
Knowledge of the architecture of engines and the related dynamic issues.
Knowledge of the main components for the air and fuel management.
Knowledge of issues related to combustion processes and related influence on the engine efficiency and emissions of pollutants.
Capability of defining the design specifications for propulsion systems keeping into account the technological, economic and environmental constraints.
Capability of defining the architectures of propulsion systems on the base of engineering specifications.
Capability to develop the engineering and design as well as develop the engines from the Thermo-Fluid Dynamics viewpoint.
Prerequisites / Assumed knowledge
Students are supposed to have a preliminary background in thermodynamics, as well as in the kinematics and dynamics of reciprocating engines.
INTRODUCTION: CLASSIFICATIONS OF INTERNAL COMBUSTION ENGINES AND MAIN OPERATING AND PERFORMANCE PARAMETERS
Reciprocating internal combustion engines classifications based on operating characteristics and on operating cycle duration (four-stroke or two-stroke).
Ideal efficiency, indicating efficiency, mechanical efficiency definitions.
IMEP, BMEP, FMEP definitions and trends vs air/fuel ratio and engine speed.
RECIPROCATING ENGINE BALANCING
Forces and torques acting on the engine.
Criteria for the selection of the angular shift of the cranks and for their longitudinal arrangement on the crankshaft.
Balancing of the residual forces and torques with the support of masses on additional shafts.
V-engines, radial engines and "boxer" engines.
Volumetric efficiency in four-stroke engines: characteristics, detailed study of the gas exchange process.
Supercharging and turbocharging.
Fuelling of SI engines:
- General requirements, problems with tip-in manoeuvres and cold starts.
- Electronic injection systems.
- Direct injection.
- Fuelling systems for engines using gaseous fuels.
Fuelling of CI engines:
- Requirements in terms of atomization and penetration of the fuel jet.
- Mechanical injection systems and "common rail" injection systems.
Overview: reaction velocity and ignition temperature. Rapid compression machines and air/fuel mixtures induction times. Fuels for SI and CI engines.
COMBUSTION IN SI ENGINES
Parameters which determine the flame front speed.
Abnormal combustion: pre-ignition, auto-ignition, misfiring, knock.
Standard and non-conventional methods for the measurements of the knocking intensity. Octane number of fuels.
COMBUSTION IN CI ENGINES
Ignition delay, fuel injection rate and fuel burning rate. Effects of multiple injections. Combustion noise.
Cetane number of fuels.
Non-conventional combustions (HCCI, PCCI, etc).
Environmental and health effects, current regulations, type approval driving cycles.
Pollutant emissions formation mechanisms.
Technologies for pollutants control: "in cylinder" technologies (EGR) and after-treatment technologies (three-way catalysts, particulate traps, LNT and SCR catalysts).
HYBRID ELECTRIC VEHICLES
Control strategies and operating modes.
Training / Laboratories
Design of the flywheel for a 4-stroke reciprocating engine for automotive application (for both a single cylinder engine and a multi-cylinder engine).
Indicating analysis for a 4-stroke s.i. engine.
Combustion analysis and calculation of the heat release rate.
Fuel consumption and emissions calculations of a passenger car over the NEDC driving cycle.
Disassembly of a 4-stroke reciprocating engine.
Experimental measurements on a SI engine.
Experimental measurements on a CI engine.
Texts, readings, handouts and other learning resources
Attending both theoretical and practical lectures is warmly recommended, since there is not a single text for all the topics of the subject.
For more details on specific topics, the following books can provide a comprehensive reference:
- G. Ferrari: "Motori a combustione interna", Ed. Il Capitello, Torino, 2008 (4 ed.).
- J. B. Heywood: "International combustion engine fundamentals", McGraw-Hill, 1988.
- "Automotive Handbook", R. Bosch Ed., 7° Ed., 2007 – ISBN 978-0-76801953-7.
Assessment and grading criteria
The final exam is only in written form and it is made of 4 questions (open answers) and 1 numerical problem, for a total duration of 2 hours.
The use of books, notes or any other kind of support material is not allowed.
A sample of a typical exam test will be distributed through the Web before the end of the semester, so to allow students to perform a self-evaluation test before the final exam.
Reports assigned during the semester must be delivered to the lecturer before the written exam, mandatorily: although the reports will not be evaluated for the final score, students are requested to deliver their reports to be admitted to the final written exam.
Programma definitivo per l'A.A.2017/18