• 052391 - MODELING OF AUTOMOTIVE PROPULSION SYSTEMS [2]

This course aims to provide an extensive know-how about typical modeling techniques applied to IC engines (both spark ignition and compression ignition) and hybrid/electric powertrains, in order to predict the efficiency of on-board energy conversion process and the related pollutant emissions, as function of different architectures (IC engine, hybrid series/parallel, plug-in, full electric vehicle).

The course provides experience with IC engine and hybrid/electric vehicle modeling tools. Simulation codes are applied to build up integrated models of the various components. A numerical laboratory is included to allow a direct application of a few simulation tool

Power electronics and electrical machines applied to series/parallel hybrid vehicles are analyzed, as for their structure, performance, dynamical modelling and simulation. The thermal behaviour will be studied too.

After completing the course students will be able to:

• understand the modeling approaches and numerical techniques adopted to simulate the most important processes in IC engines, power electronics, electrical machines and hybrid vehicles;
• evaluate all relevant parameters of automotive propulsion systems, taking into account the vehicle architecture, operation and interaction among different components;
• assess the advantages/disadvantages of each solution in terms of performances, pollutant and CO2 emissions, flexibility, range;
• have knowledge about the potential and field of application of simulation tools for IC engine performance and emissions;
• have a good familiarity with the use of 0D/1D thermo-fluid dynamic tools and simplified vehicle simulation tools for a preliminary analysis of automotive propulsion systems;
• understand the application and control of electrical motors and generators in vehicles.

1D simulation of intake and exhaust systems by fluid dynamic models: prediction of unsteady flows; fundamental equations and numerical methods; boundary conditions

Single zone and multi-zone thermodynamic combustion models: SI and CI engines; balance equations, solution methods; chemical equilibrium and simplified kinetic sub-models.

Prediction of typical pollutant emissions from SI and CI engines: CO, HC, NOx, soot, by means of suitable kinetic sub-models and simplified semi-empirical models.

Conversion of pollutants in after-treatment systems: modeling of chemical reactions and conversion efficiency of three-way catalyst, SCR, oxidation catalyst, DPF.

Conventional/hybrid vehicle simulations under real driving conditions: calculation of performances (engine efficiency, fuel consumption and CO2 emission) and emissions, considering different vehicle architectures.

Power Electronics and converters: Description of the characteristics of diodes and controllable switches (Mosfets, IGBTs, …). Thermal behaviour. Diode bridge rectifiers. Switch mode dc-dc converters: buck, boost, buck-boost converters. PWM modulation. Switch mode dc-ac converters: single phase and three-phase structure. Sinusoidal PWM modulation: voltage and current harmonics.

Electrical Machines for traction: Permanent Magnet Brushless AC Synchronous machine: structure, operation principle when current-controlled at variable frequency, mechanical characteristic. Induction machine: operation principle, mechanical characteristic with variable frequency, flux weakening. Synchronous Permanent Magnet Outer Rotor (In-Wheel) Motor.

Design of the electrical main components of a series hybrid vehicle starting from the driving characteristics.

Modelling of the regenerative braking system.

Notions of IC engines from the MSc level; notions of thermodynamics, chemistry and fluid machines from the BSc level.

Principle of Electrical Engineering. Electric Power Systems (or Sistemi e Macchine Elettriche).

Evaluations at all official exam dates will consist of a written exam (2 hours) with open theoretical and numerical questions.

A facultative oral discussion is available to complete the exam for the highest marks (≥28) and not foreseen in all other cases.

The student can choose to take just one part of the examination (thermal engines or electric components), in half of the available time (1 hour). The partial mark is considered valid up to the exam dates in January-February. The choice to take just one part of the exam can be communicated to the teachers also after reading the task.

If the student takes the whole exam, he cannot reject the mark of one part. The rejection implies the repetition of the whole exam.

Assume that the mark in one part of the exam is low, and the student wants to repeat that part. When he takes the exam again and hands in his written task, the previous mark of that part is cancelled: the student cannot choose between the previous and the actual mark.

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.

available on beep

available on the Electronic Library of Polimi

available on beep