Utjecaj debljine diskova kočnica trkaćeg vozila na njihovo zagrijavanje tijekom vožnje

master's thesis

• Title (english): Impact of race car's brake discs' thickness on their heating during driving
• Author: Zvonimir Ercegovac
• Mentor: Zoran Lulić (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2022-01-21, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; General Mechanical Engineering (Construction)

Abstract

Sustavi kočenja u vozilima služe za brzo i kontrolirano usporavanje i zaustavljanje vozila. Kinetička energija vozila umanjuje se pretvorbom u druge oblike energije, većinom u toplinsku energiju. Pritom kočni diskovi preuzimaju oko 90 % topline [1] i moraju je disipirati kako ne bi došlo do njihovog pregrijavanja. Budući da se mase kočnih diskova ubrajaju u neovješene mase vozila i mase koje se rotiraju zajedno s kotačima, njihovo smanjenje predstavlja potencijal za poboljšanje dinamike vozila, udobnosti vožnje te potrošnju goriva i emisije štetnih plinova, no i rizik za pregrijavanje i kompromitiranje funkcije kočenja.

Rad je izrađen s ciljem određivanja najmanje debljine prednjih i stražnjih kočnih diskova koje uz ostale konstrukcijske zahtjeve zadovoljavaju i toplinske zahtjeve u sklopu razvoja trkaćeg vozila. U početku rada iznesen je kratki pregled povijesnog razvoja sustava kočenja u automobilima te su opisane teorijske osnove na kojima počiva metoda korištena pri ispitivanju na trkaćoj stazi i analizi uvjeta rada kočnih diskova postojećeg vozila. Prikazan je plan eksperimenata koji su provedeni kako bi se definirali ulazni podatci potrebni za provedbu analize. Opisan je tranzijentni toplinski simulacijski model korišten u sklopu analize, korištene postavke i rubni uvjeti modela.

Potom su detaljno proučeni termodinamički uvjeti rada kočnih diskova i dokumentirani su načini kako su prikupljeni ulazni podatci za simulacijski model. U završnoj fazi rada, kalibrirani simulacijski model primijenjen je za još jednu usporedbu s vrijednostima izmjerenima na testiranju vozila i na simulaciju vožnje po odabranoj stazi. Iterativnim postupkom simulirano je korištenje različitih debljina kočnih diskova i odabrana je debljina prednjih i stražnjih kočnih diskova novog trkaćeg vozila.

Abstract (english)

Brake systems in vehicles are used to slow down and stop vehicles quickly and in a controlled manner. Kinetic energy of the vehicle is reduced by converting into other forms of energy, primarily into heat. The brake discs thereby take in about 90 % of the heat [1] and must dissipate it, so as not to overheat. Considering that the masses of brake discs account into unsprung masses and masses which rotate together with the wheels, their reduction presents a potential for improving vehicle dynamics, ride comfort along with fuel economy and harmful gas emissions, but also a risk of overheating and compromising the function of braking.

This thesis is produced with a goal of determining the minimal thicknesses of front and rear brake discs which, along with other design requirements, fulfil thermal requirements too in the process of development of a race car. In the beginning of the work, a short view back to the past of the development of brake systems in cars is presented and the theoretical foundations on which the method used for testing on a racetrack and analysis of the operating conditions of the existing vehicle are explained. A plan of experiments conducted to define the input data required for the analysis is shown. A transient thermal simulation model is described, used as a part of the analysis, the settings used and boundary conditions as well.

Afterwards, thermodynamic operating conditions are examined in detail and the ways to gather input data for the simulation model are documented. In the final phase of the thesis, the calibrated simulation model is applied for another comparison to the data measured during vehicle testing and to simulate driving on a chosen track. The usage of different thicknesses of new race car’s brake discs is simulated through iterating.

• Keywords: sustav kočenja; kočnice; kočni diskovi; kočni disk; tranzijentna simulacija; toplinska simulacija; mjerenje temperature; infracrveni senzor; temperaturni senzor
• Keywords (english): brake system; brakes; brake discs; brake disc; transient simulation; thermal simulation; temperature measurement; infrared sensor; temperature sensor
• Language: croatian
• URN:NBN: urn:nbn:hr:235:056685
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2024-01-12
• Created on: 2022-01-13 20:10:26