Konstrukcija pasivne i aktivne pretkomore za Ottov motor motocikla

undergraduate thesis

• Title (english): Design of passive and active pre-chamber of SI engine for motorcycle
• Author: Branimir Rakić
• Mentor: Momir Sjerić (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2023-09-27, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; General Mechanical Engineering (Construction)

Abstract

Primjena pretkomora u Ottovim motorima posljednjih godina dobiva sve više na značaju zbog
toga što zahtjevi za smanjenjem štetnih emisija iz motora postaju sve stroži. Uporabom ovakvog
prostora izgaranja omogućava se izgaranje siromašne smjese čiji su glavni nedostatci teško
paljenje i detonantno izgaranje. U svrhu smanjenja tih nedostataka, u glavu motora ugrađuju se
pretkomore koje omogućavaju brže paljenje smjese u glavnom prostoru izgaranja, čime se
smanjuju vršne temperature, toplinski gubici i emisije dušikovih oksida NOx.
Kod klasičnih Ottovih motora, korištenje uobičajene svjećice ne rezultira izgaranjem siromašne
smjese već je potrebna ugradnja pretkomore koja sadrži brizgaljku (ubrizgava minimalnu
količinu goriva) i svjećicu (zapaljuje bogatu smjesu). Ostatak goriva ubrizgava se direktno u
cilindar ili u usis gdje se miješa sa zrakom te potom ulazi u cilindar. Ugradnjom pretkomore
smanjuju se gubici izmjene radne tvari, a povećava učinkovitost motora zbog mogućnosti
regulacije snage kontrolom faktora pretička zraka.
U ovom radu prikazane su razne izvedbe pretkomora, razrađen je princip aktivne i pasivne
pretkomore kojeg prate 3D CAD modeli i pripadajuća tehnička dokumentacija. Osim modela
pretkomora napravljen je i 3D CAD model šasije motocikla Yamaha XT 600E sa Ottovim
motorom na kojeg je nadograđena svaka pretkomora zasebno.

Abstract (english)

The use of prechambers in Otto engines has gained more and more importance in recent years
due to the fact that the requirements for reducing emissions from engines are becoming more
and more strict. The use of such a combustion space enables the combustion of a lean mixture,
the main disadvantages of which are difficult ignition and detonating combustion. In order to
reduce these defects, prechambers are installed in the engine head that enable faster ignition of
the mixture in the main combustion chamber, thereby reducing peak temperatures, heat losses
and emissions of nitrogen oxides NOx.
In conventional Otto engines, the use of a normal spark plug does not result in the combustion
of a lean mixture, but requires the installation of a prechamber containing an injector (injects a
minimum amount of fuel) and a spark plug (ignites a rich mixture). The rest of the fuel is
injected directly into the cylinder or into the intake port where it mixes with air and then enters
the cylinder. The installation of the prechamber reduces the losses of the exchange of the
working substance, and increases the efficiency of the engine due to the possibility of power
regulation by controlling the air to fuel ratio.
In this paper, various versions of the prechamber are presented, the principle of active and
passive prechamber is elaborated, followed by 3D CAD models and related technical
documentation. In addition to the model of the prechamber, a 3D CAD model of the chassis of
the Yamaha XT 600E motorcycle with an Otto engine was also created, on which each
prechamber was upgraded separately.

• Keywords: Ottov motor; pretkomora; aktivna i pasivna pretkomora
• Keywords (english): Otto engine; prechamber; active and passive prechamber
• Language: croatian
• URN:NBN: urn:nbn:hr:235:695501
• 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: 2023-09-25 19:50:29