The knowledge acquired by the students upon completion of this course involves: • to interpret a simple fluid power scheme according to the ISO standard 1219, • to identify the main fluid power components, their specific function and operation, • to know the fundamental equations for the evaluation of the flow rate, pressure, speed, torque and power, • to identify and quantify the sources of power dissipation in a fluid power system and evaluate the efficiency, • to learn the working principle of the main automotive fluid power systems and components, • to learn the basics of some commercial tools for the simulation of fluid power circuits. With the skills acquired during the course, students should be able to: • design a simple layout of a fluid power system, • select and size the correct component (pump, actuator, valve) to achieve a specified function, • analyse qualitatively and quantitatively the different working modes of a fluid power circuit, • understand the working principle of the following fluid power systems: hydraulic steering units for passenger cars and off-road vehicles, electrohydraulic braking systems, closed circuit hydrostatic transmissions and lubricating circuits for internal combustion engines.

Awareness of basic concepts covered in Physics and Fluid Mechanics.

Main topics are the following: • Fundamentals of Fluid Power (8 hours). ISO standard 1219, fluid properties, functional blocks. • Positive displacement pumps and motors (8 hours): different designs, real steady-state characteristics flow-pressure and flow-speed, instantaneous flow rate and torque, volumetric and mechanical-hydraulic efficiencies, flow and torque losses models. • Fluid Power valves (6 hours): on-off directional control; flow and pressure control (pressure relief, pressure reducing, sequence, two-port and three-port flow control), single and double stage; ideal and real performance characteristics; analysis of real components. • Accumulators (1 hour): types and their dimensioning criteria. • Flow generation units (5 hours): constant and variable flow rate, for open and closed circuits; constant pressure; ideal and real performance characteristics. • Power steering units and hydrostatic steering units (8 hours): working principles, analysis of sections of the rotary valves, fixed and variable displacement pumps, priority valves. • Electro-hydraulic braking system (7 hours): brake booster, vacuum pump, tandem master cylinder, ABS modules (from 2S to 8). The ESP integration for lateral stability. • Hydraulic valve train (1 hour): hydraulic lash adjusters, variable valve actuation. • ICE lubrication systems (6 hours): layout (wet and dry sump solutions), oil path and pressure distribution inside the crankshaft; journal bearings: pressure distribution (Sommerfeld and Ockvirk bearings), load capacity, through flow; cooling jets; fluid conditioning group; lubricating pumps, fixed and variable displacement, with discrete pressure controls; evaluation of the pressure and flow rate through the circuit as function of oil temperature and engine speed. Basic properties of the lubricants. • Hydrostatic transmissions (4 hours): transmission ratio and torque ratio, characteristics of primary variable-secondary fixed, primary fixed-secondary variable, primary variable-secondary variable versions, total efficiency, corner power and torque conversion range. Multi-function valves. Multi-motor transmissions. • Lumped parameter simulation of fluid power components (6 hours).

The course is made up of theoretical lectures (the onsite attendance is highly recommended), applied lectures and laboratory sessions. In the applied lectures, some numerical exercises are solved with the assistance of the teacher and the components/circuits used for the laboratory experiences are explained. During the semester, five numerical exercises will be progressively proposed on the didactic web portal of the Politecnico. This homework must be downloaded and solved individually, according to explicit rules, by all students. The purpose of the homework is twofold: a self-assessment of acquired knowledge and competence; a training route toward the final written test. Students will have to upload on the didactic web portal a scanned copy of their handwritten set of homework (see exam rules). Two sessions of laboratory work (1.5 hours each) are carried out at the Fluid Power Research Laboratory (Main Campus): • Pumps/motors and didactic test rig: different types of positive displacement pumps and motors (external and internal gear, axial and radial piston and vane machines) are disassembled and analysed. Moreover, the working principle of a simple hydraulic circuit is tested on a didactic rig. • Steering servo systems, electro-hydraulic braking system and lubricating circuit: the main components are disassembled and analysed. Moreover, the working principle of a hydrostatic steering unit is demonstrated on a dedicated test rig. Four sessions of simulation work (1.5 hours each) are carried out. Briefly introducing simulation environments (Simcenter Amesim and GT-Suite), problems in modelling and simulation of simple components and systems are presented. Students have the opportunity to perform simulations to gain direct experience of the approach and perception of the involved potentials. A written report about the simulation experiences (short model description, requested plots and brief comment of the results) must be prepared and uploaded along with the homework. Finally, students are invited (optional activity) to reproduce on their own some simple hydraulic circuits using the free Student Edition of Amesim; some examples of simulation are shown during the lectures.

In order to avoid students to print on their own the didactic material, the entire set of slides used during the semester in high quality B/W printed form will be available at the beginning of the didactic term: • Nervegna, Rundo: Automotive Fluid Power Systems, EPICS Edizioni, Torino. ISBN 978-88-94802-06-1 (also available on the eCommerce site – www.centroappunti.it) New improved and corrected reprints are available yearly at the end of February. Moreover, blocks of slides (with possible minor updates) will be progressively made available only to enrolled students on the Didactic Web Portal in electronic and colour version at the end of the lectures. However, students are strongly invited to integrate the material with their own notes. A glossary with the main Fluid Power terms will be also uploaded on the web portal. For additional insight into specific topics, reference is made to the following books: • Nervegna, Rundo: Passi nell’Oleodinamica, EPICS Edizioni, Torino, 2020 (in Italian). ISBN 978-88-94802-15-3 (also available on the eCommerce site – www.centroappunti.it). The students enrolled in the course can buy the book with a 65% discount on the cover price. • Gilardino: Esercizi di Oleodinamica, CLUT, Torino, 2010 (in Italian). • Padovani: Practical exercises about hydraulic components and systems, CLUT, Torino, 2020 (in English). Additional information about the Fluid Power field, the didactic (bibliography, links, testimonials of former students, list of theses, animations and much more) and the research activities can be found on the official web site of the Fluid Power Laboratory (http://www.fprl.polito.it).

Exam: Written test; Optional oral exam; Individual essay;

GENERAL RULES The aim of the exam is to assess the acquired knowledge and the skills listed in the section “Expected Learning Outcomes”. The final exam is made up of a written test and an optional oral test. The written exam is composed by two parts (1 hour each). The first part involves numerical questions on a proposed problem (max 15 points). The progressive stages of all calculations must be shown: any formula used, how the numbers are substituted into the formula and the final result in the requested unit. The answer is considered fully correct only if the formula used and the result are both correct. The second part includes 6 theoretical multiple-choice questions (max 9 points) and 1 open-ended question (6 points) on all concepts and principles exposed during the lectures and laboratory sessions. In multiple-choice questions (with three answers, only one correct), student must be able to demonstrate the knowledge of the basic concepts; 1,5 marks are assigned if the answer is correct, 0 marks for no answer, a penalty of 0,5 marks for incorrect answer. In the open-ended question, candidates must be able to explain the working principle of a component or of a system, to discuss about advantages and drawbacks of different solutions, to derive analytic governing equations, to obtain the theoretical and real steady-state characteristics and to draw the basic hydraulic circuits using the correct standard symbols. The test is a “NO BOOK EXAM”: the use of personal notes, books and manuals in any form (hard copies and electronic versions) is strictly forbidden. Candidates can have on the desk only identity document, blank sheets, writing instruments and a scientific calculator. Some examples of written tests with solutions will be available on the didactic web portal before the end of the course. The results of the written test will be published on the didactic web portal as soon as possible. For those who reach in the written test a mark in the range: • greater or equal to 18/30, the oral examination is optional, • from 14/30 to 17/30, an additional chance is given by means of an oral examination for passing the exam, • below 14/30, the exam is failed. Students who have potentially passed the exam (mark in the written test > 17/30) can retake the exam if not satisfied with the mark (the exam will be recorded as failed). In case of oral exam, the final mark will be the average between oral (max 30 points) and written (max 30 points) part. If the combined mark is < 18/30 the exam is failed and it will be necessary to retake the written test, otherwise the exam is passed (it is not possible to reject the mark). The oral exam (typically 2 or 3 questions) will focus on lectures and laboratory topics in a similar manner as the theoretical open-ended question in the written test. The duration of the oral exam is strictly related to the preparation of the student. The mark will consider the completeness/correctness of the answers, as well as the ability of discussing critically the topics. The students must also upload the homework/report (described in the section Course Structure) within the day scheduled for the written exam. No additional point will be awarded for the homework. On the contrary, a penalty up to 2 points can be applied on the final mark in case of incomplete homework. The mark “30 cum laude” can be obtained in case of an outstanding exam (written only or written+oral) demonstrating a very deep knowledge of the subject. RULES SPECIFIC FOR ONSITE EXAM In case of withdrawal from the written test, the exam paper must be returned. No extra time will be allowed for late arrivals. The day scheduled for the oral exams will be also devoted for showing the corrected written tests and for clarifications about the corrections. The will to accept the mark, to take the oral exam or to reject the mark can be expressed in the same day. In case of absence and no communication by email: • if the mark is higher than 17/30, such a mark becomes final and the exam is passed. • if the mark is 17/30 or lower the exam is failed. Appropriate actions will be taken against students who: • use any unauthorised source of information, • communicate or share written materials with other candidates, • attempt to read other candidates’ work. In case of misconduct, at discretion of the Exam Board: • the answer to some questions can be nullified (0 points will be assigned) • the student could be expelled from the exam room (the exam will be recorded as failed) and deferred to “Commissione disciplinare” for punishment.

In addition to the message sent by the online system, students with disabilities or Specific Learning Disorders (SLD) are invited to directly inform the professor in charge of the course about the special arrangements for the exam that have been agreed with the Special Needs Unit. The professor has to be informed at least one week before the beginning of the examination session in order to provide students with the most suitable arrangements for each specific type of exam.