Analiza primjenjivosti 0D modela izgaranja Ottovog motora na radne točke koje koriste povrat ispušnih plinova

master's thesis

• Title (english): The analysis of applicability of 0D SI combustion models in operating conditions that use exhaust gas recirculation
• Author: Stipe Mustać
• Mentor: Darko Kozarac (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2018-03-28, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U ovom radu analizirana je mogućnost postojećih simulacijskih modela izgaranja da dobro predviđaju stanje u cilindru. Motor korišten u analizi je HATZ 1D81 s uključenim povratom dijela ispušnih plinova (Exhaust Gas Recirculation, EGR), koji se nalazi u Laboratoriju za motore i vozila na Faklutetu strojarstva i brodogradnje u Zagrebu. Prethodno analizi, rad motora se ispitao na eksperimentalnom postavu u Laboratoriju te su izmjereni podaci u različitim uvjetima rada. Simulacije rada motora... More izvedene su u simulacijskom alatu AVL BOOST v2013.2 za 11 radnih točaka s različitim udjelima EGR-a, različitim temperaturama i tlakovima na usisu, različitim trenutkom preskakivanja iskre na svjećici (Spark Timing, ST), itd. U posljednje vrijeme razvoj vozila pogonjenih motorom s unutarnjim izgaranjem je pod sve većim pritiskom izazvanim strogim ECE-pravilnicima u vidu ograničenja količine štetnih emisija te sve konkurentnijim elektičnim vozilima različitih izvedbi. Konstrukcija i sustavi motora s unutarnjim izgaranjem moraju napredovati, a kako najveću ulogu u radu motora ima stanje u cilindru, isto je tema ovog rada. Za analizu stanja u cilindru prilikom izgaranja korišteni su postojeći prediktivni kvazi-dimenzijski 1-D/0-D modeli izgaranja, tj. fraktalni model izgaranja (Fractal Combustion Model, FCM) i model praćenja plamena (Flame Tracking Model, FTM). Za simulaciju stanja u cilindru u modelu FCM korišten je pod-model turbulencije K - k, gdje je K kinetička energija glavnog strujanja, a k turbulentna kinetička energija. Za simulaciju stanja u cilindru u modelu FTM korišten je pod-model turbulencije k - ε, gdje je ε disipacija turbulentne kinetičke energije. Rješenja simulacija s primjenjenim navedenim modelima su ovisna o vrijednostima ulaznih parametara modela. Za točnu upotrebu modela izgaranja, tj. za dobivanje mjerodavnih rješenja simulacija za različite radne točke, svi modeli se moraju prvo parametrizirati. Cilj parametrizacije je određivanje jedinstvenog seta parametara ili seta parametara koji zahtijeva minimalne naknadne promjene, a da se stanje u cilindru predviđa što bolje za svih 11 radnih točaka. Konačna rješenja nakon zasebene parametrizacije modela izgaranja su uspoređena s eksperimentalnim vrijednostima i odabran je model kod kojeg su vrijednosti stanja u cilindru dobivene simulacijom bliže eksperimentalnim vrijednostima te je validirana njegova ukupna točnost. Za kraj, na modelu izgaranja kod kojeg su vrijednosti stanja u cilindru dobivene simulacijom bliže eksperimentalnim vrijednostima, uključen je pod-model izračuna detonantnog izgaranja. Rezultati simulacije detonantnog izgaranja su također uspoređeni s eksperimentalnim vrijednostima i validirana je točnost primjenjenog modela detonacije. Less

Abstract (english)

In this thesis, the possibility of combustion simulation models is analysed in order to properly anticipate conditions in the cylinder. The engine used in the analysis is HATZ 1D81 with exhaust gas recirculation (EGR), which is located in Laboratory for engines and vehicles in the Faculty of Mechanical Engineering and Naval Architecture in Zagreb. Prior to the analysis, the engine operation was indicated on a test bead in the Laboratory and the experimental data were measured in... More different operating conditions. Engine work simulations were performed using a simulation tool called AVL BOOST v2013.3 for 11 operating points with different EGR percentages, different intake temperatures and pressures, different spark timings (ST), etc. Lately, the development of internal combustion engines (ICE) has been under an ever-growing pressure caused by the strict ECE-regulations when it comes to the limitations of harmful emissions, as well as the increasing number of competitive electric vehicles different kind. The constant development of ICE is of extreme importance and since the conditions in the cylinder are the main part of a working engine, they were chosen to be a subject of this thesis. For the analysis of the cylinder conditions during combustion, an existing predictive quasi-dimensional 1-D/0-D combustion models are used, those being the Fractal combustion model (FCM) and the Flame tracking model (FCM). A K - k turbulence sub-model is used for the simulation of cylinder conditions in FCM, in which K stands for the kinetic energy of mean flow, while k stands for the turbulent kinetic energy. A k - ε turbulence sub-model is used for the simulation of cylinder conditions in FTM, in which ε stands for dissipation of turbulent kinetic energy. The solutions of simulations, with applied models mentioned above, are dependent on input parameters setting. All models have to be parameterised for the correct usage of the combustion model, i.e. for getting the relevant solutions for different operating points. The goal of parameterisation is determining a unique set of parameters or a set of parameters which needs minimum subsequent changes while, at the same time, having the best predictions as possible for the cylinder conditions for all 11 operating points. After a separate parameterisation of the combustion models, the final solutions are compared with experimental data. Consequently, the model which gives the solutions of simulation that are closer to the experimental data is chosen, and its overall accuracy is validated. Finally, a sub – model of knock is applied on the combustion model, the latter being the one which gives the solutions of simulation that are closer to the experimental data. These results are also compared with experimental data and overall accuracy of applied knock model is validated. Less

• Keywords: motor s unutarnjim izgaranjem; kvazi-dimenzijski 1-D/0-D modeli izgaranja; AVL BOOST; turbulencija; detonacija
• Keywords (english): internal combustion engine; quasi-dimensional 1-D/0-D combustion models; AVL BOOST; turbulence; knock
• Language: croatian
• URN:NBN: urn:nbn:hr:235:770189
• 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
• Created on: 2019-05-22 22:16:32