Numerička analiza utjecaja geometrijskih i radnih parametara na pojavu detonacije u Ottovom motoru

undergraduate thesis

• Title (english): Numerical analysis of influence of design and operating parameters on occurrence of knock in a spark ignited engine
• Author: Borna Savović
• Mentor: Darko Kozarac (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2018-02-28, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Detonacija je neželjeni način izgaranja koji se najčešće javlja na motorima s Ottovim procesom izgaranja. Intenzitet detonacija može biti blaže prirode i očitovati se vibracijama u motoru i pojačanim zagrijavanjem komponenata, a može biti i intenzivnije prirode što u vrlo kratkom periodu može dovesti do havarije motora. Na pojavu detonacije u radu Ottovih motora utječu razni geometrijski i radni parametri. Najvažniji su trenutak pretpaljenja, kompresijski omjer i faktor pretička zraka. U svrhu numeričke analize utjecaja promjene geometrijskih i radnih parametara na pojavu detonacije u Ottovom motoru korišten je programski paket AVL Boost. Sva ispitivanja su provedena za pet različitih opterećenja (20, 40, 60, 80 i 100%) na modelu motora koji je prethodno napravljen. Analizira se utjecaj promjene kompresijskog omjera, početka izgaranja, temperature rashladnog medija, nabijanja, opterećenja te brzine vrtnje motora na povećavanje, odnosno smanjenje sklonosti pojave detonacije u radu Ottovog motora.

Abstract (english)

A knock is an unwanted type of combustion which usually occurs in engines with Otto cycle process. The intensity of knock can be smaller and cause vibrations and overheating or, in case of its higher intensity, it can be potentially devastating and cause failure of the engine in a very short time. The occurrence of the knock is influenced by various geometrical and working parameters. The most important of them are: time of ignition, compression ratio and air to fuel ratio. For the purpose of the numerical analysis of the influence of changing geometrical and working parameters on the occurrence of the knock in Otto engines, the computer program AVL Boost has been used. All tests have been made for five different loads of engine (20, 40, 60, 80 i 100%) on model of engine which had previously been made. The influence of changing of compression ratio, start of ignition, temperature of cooling liquid, supercharging, load of engine, rotation speed on the increase or decrease in the chance of the knock is analysed.

• Keywords: detonacija; geometrijski i radni parametri; numerička analiza
• Keywords (english): knock; geometrical and working parameters; numerical analysis
• Language: croatian
• URN:NBN: urn:nbn:hr:235:630045
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-05-22 22:04:45