Vpliv zmesi dizelskega goriva in metanola na zgorevanje v motorju na kompresijski vžig

zaključna naloga Razvojno raziskovalnega programa I. stopnje Strojništvo

Vid Zuljan (Author), Tine Seljak (Mentor)

Abstract

V nalogi obravnavamo vpliv zmesi dizelskega goriva in metanola na zgorevanje v motorju na kompresijski vžig. Namen dodatka metanola k dizelskemu gorivu je predvsem v zmanjšanju okolju škodljivih izpustov, pri čemer je potrebno ohraniti globalne parametre delovanja motorja; to so moč, efektivni izkoristek ter poraba goriva. Za metanol je značilna visoka vsebnost kisika, nizka gostota ter visoka izparilna toplota, za njegovo pridobivanje pa obstaja vrsta postopkov, ki omogočajo izkoriščanje obnovljivih virov energije. V nalogi je na podlagi simulacij v programu AVL Fire ovrednoten vpliv 10%, 20% in 30% masnega deleža metanola pri vbrizganem gorivu. Poleg tega je ovrednoten tudi vpliv kota vbrizga (690%, 707% in 715%) in vpliv deleža recirkuliranih izpušnih plinov (0%, 30% in 70%). Rezultati nakazujejo, da se z večanjem deleža metanola poveča čas zakasnitve vžiga, kar povzroči višjo stopnjo sproščanja toplote ter krajše trajanje zgorevanja. Zaradi zgorevanja pozno po zgornji mrtvi legi se zmanjšajo izpusti NOx, povečajo pa se izpusti saj. Zgodnejši kot vbrizga poveča tlak, temperaturo in stopnjo sproščanja toplote v valju, poznejši kot vbrizga pa povzroča diametralne efekte. Izpusti NOx so višji pri zgodnejšem vbrizgu. Podobno kot metanol, tehnika EGR povečuje zakasnitvene čase in zmanjšuje tlak in temperaturo v valju. Hitrost sproščanja toplote se namreč poveča zaradi daljšega zakasnitvenega časa. Podrobna analiza koncentracij posameznih radikalov dodatno razkriva, da se predvsem radikal OH v največji meri tvori v območju najintenzivnejšega zgorevanja.

Keywords

diplomske naloge;motor na kompresijski vžig;metanol;zgorevanje;tehnika EGR;kot vbrizga;emisije;

Data

Language:	Slovenian
Year of publishing:	2020
Typology:	2.11 - Undergraduate Thesis
Organization:	UL FS - Faculty of Mechanical Engineering
Publisher:	[V. Zuljan]
UDC:	621.436:665.753:661.721(043.2)
COBISS:	30778371
Views:	871
Downloads:	116
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Effect of diesel-methanol blends on combustion in compression ignition engine
Secondary abstract:	In the thesis the effect of diesel-methanol blends on combustion and emission characteristics is studied. The main objective of methanol addition is to lower exhaust emissions, while keeping other engine parameters within acceptable ranges (eg. power, effective efficiency and fuel consumption). Methanol features high oxygen concentration, low sulfur concentration, low density and high latent heat of vaporization, while it can be produced from renewable sources with various technologies. Based on simulations carried out in AVL Fire the effect of 10%, 20% and 30% methanol-diesel blends was evaluated. Furthermore the influence of injection timing (690%, 707% and 715%) and the effect of EGR (0%, 30% and 70%) were also studied. The results show that with an increase in methanol fraction the ignition delay became longer, which caused higher heat release rate in premixed phase of combustion and consequently shorter burn duration. Due to late combustion after top dead center, temperature and pressure in the cylinder decreased with increasing methanol fraction. Consequently NOx emissions were lower while soot emissions were higher than those for neat diesel. Advanced injection timing (690%) caused an increase in pressure and temperature while ignition delays were also longer for all fuels. Meanwhile retarded injection exhibited diametrical results. Emissions of NOx increased with advanced and decreased with retarded injection. The use of EGR provoked an increase in ignition delay time, while also lowering pressure and temperature in the cylinder. Consequently NOx emissions decreased. Detailed analysis of radical formation revealed that OH radical mostly formed in the area where combustion rate reached it's peak.
Secondary keywords:	thesis;compression ignition engine;methanol;combustion;injection timing;emissions;
Type (COBISS):	Final paper
Study programme:	0
Embargo end date (OpenAIRE):	1970-01-01
Thesis comment:	Univ. v Ljubljani, Fak. za strojništvo
Pages:	XIV, 48 f.
ID:	12033099