Experimental investigation of influence of dual-fuel engine operating parameters on combustion, efficiency and exhaust gas emissions

doctoral thesis

• Title (croatian): Eksperimentalno istraživanje utjecaja radnih parametara dvogorivnog motora na način izgaranja, učinkovitost i emisiju štetnih tvari
• Author: Mario Sremec
• Mentor: Darko Kozarac (mentor)
• Committee member: Zoran Lulić (predsjednik povjerenstva)
• Committee member: Momir Sjerić (član povjerenstva)
• Committee member: Vladimir Medica (član povjerenstva)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2018-12-05, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; General Mechanical Engineering (Construction)
• Universal decimal classification (UDC): 621.3 - Electrical engineering

Abstract

The strict regulations related to exhaust gas emissions from internal combustion engines in the transport sector, created by governments around the world, forces manufacturers to improve existing combustion techniques, develop new ones and apply alternative, environmentally more acceptable fuels. In this context, natural gas is recognized as an alternative fuel which can be used both in spark ignition and compression ignition engines with a number of benefits. In recent years, special attention has been given to the research of diesel-natural gas dual-fuel combustion, which has potential to reduce greenhouse gas emissions, as well as harmful exhaust gas emissions. Given that this combustion technique is not fully investigated, but can be easily used in existing diesel engines, there is a need for further improvement, which is the main objective of this work. The purpose of the research is to experimentally examine possibilities of using compressed natural gas in conventional dual-fuel internal combustion engine, with goals that include achieving maximum efficiency and maintaining exhaust gas emissions on permitted levels. Special attention was given to the improvement of characteristics at low and high loads, where dual-fuel shows some disadvantages compared to the normal diesel operation. By using the fully flexible fuel injection system and exhaust gas recirculation, there were achieved different combustion techniques including: diffusion flame combustion, premixed flame propagation and premixed chemically controlled combustion of homogeneous or stratified mixture. It is shown that adequate injection strategies in combination with other operating parameters can significantly improve exhaust gas emissions from dual-fuel engine. Finally, recommendations for selecting operating parameters at low and high loads are given.

Abstract (croatian)

Osnovni cilj ove disertacije je istraživanje mogućnosti korištenja prirodnog plina (PP) u dvogorivnom (eng. Dual-fuel) motoru s unutarnjim izgaranjem. Dvogorivni motori su modificirani Dieselovi motori kod kojih se prirodni plin koristi kao glavno gorivo, a njegovo izgaranje se inicira ubrizgavanjem male količine dizelskog goriva. Korištenje PP-a uz dizelsko gorivo pogodno je zbog čišćeg izgaranja, široke dostupnosti te potencijala za smanjenje emisije štetnih tvari u ispušnim plinovima. Glavni cilj istraživanja bio je ispitati ostvarive performanse motora i emisije koje nastaju pri dvogorivnom izgaranju. Prema pregledu literature, takvi motori imaju određenih problema pri niskim i visokim opterećenjima pa je posebna pozornost posvećena istraživanju upravljanja radom u tim radnim područjima. Na postojeći motor eksperimentalnog postava dograđen je potpuno fleksibilan sustav dobave dizelskog goriva koji omogućuje, uz korištenje povrata ispušnih plinova, postizanje različitih tehnika izgaranja koje uključuju: izgaranje difuzijskim plamenom, kombinirano izgaranje difuzijskim i predmješanim turbulentnim plamenom te predmješano kemijski uvjetovano izgaranje homogene ili slojevite smjese. Ostvarenim rezultatima pokazano je da se korištenjem adekvatne strategije ubrizgavanja u kombinaciji s ostalim radnim parametrima može značajno poboljšati izgaranje u dvogorivnom motoru, čime se postižu niže emisije štetnih tvari uz istu ili poboljšanu učinkovitost. Na kraju istraživanja, prikazane su smjernice za izbor radnih parametara na niskom i visokom opterećenju.

• Keywords: dual-fuel; compression ignition; compressed natural gas; methane alternative fuel; diesel fuel; HCCI combustion mode; combustion parameters
• Keywords (croatian): dvogorivni motor; dvogorivno izgaranje; kompresijsko paljenje; stlačeni prirodni plin; metan; alternativno gorivo; dizelsko gorivo; HCCI proces izgaranja; parametri izgaranja
• Language: english
• URN:NBN: urn:nbn:hr:235:175414
• Study programme: Title: Mechanical Engineering and Naval Architecture; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje tehničkih znanosti (doktor/doktorica znanosti, područje tehničkih znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-04-08 17:42:30