BIODIESEL AND WASTE COOKING OIL AS THE ALTERNATIVE FUELS: THE INJECTION PROCESS ASPECT

Sažetak U ovom radu će se raspraviti utjecaj uporabe alternativnih goriva na proces ubrizgavanja, karakteristika strujanja u mlaznicama i proces tvorbe mlaza. Rezultati analize dobiveni su na osnovi analiza uz uporabu paketa računske dinamike fluida FIRE, jednodimenzionalnog modela za izračun karakteristika ubrizgavanja i empirijskih izraza za izračun dimenzija kapljica ubrizganog goriva te dometa mlaza. Kalkulacije su izrađene za konvecionalan sustav ubrizgavanja s linijskom pumpom, visokotlačnim cijevima i mlaznicom sa četiri rupe. Dobiveni rezultati mogu se koristiti za ispravno podešavanje sustava za ubrizgavanje na primjeru uporabe alternativnog goriva umjesto klasičnog dizelskog goriva.Abstract The presented paper discusses the influence of using alternative fuels on the fuel injection process, in-nozzle flow characteristics and spray formation process. The analysis is performed using the computational fluid dynamics package Fire, a one-dimensional mathematical model for the injection process characteristics calculations and empirical models for calculating the injected droplet mean diameter and spray penetration length. The calculations were performed for the conventional fuel injection system with the in-line pump, high pressure tube and four-hole nozzle with the sac chamber. The results of presented analysis can be used to set properly the fuel injection system for operation with alternative fuels

BIODIESEL AND WASTE COOKING OIL AS THE ALTERNATIVE FUELS: THE INJECTION PROCESS ASPECT

Sažetak U ovom radu će se raspraviti utjecaj uporabe alternativnih goriva na proces ubrizgavanja, karakteristika strujanja u mlaznicama i proces tvorbe mlaza. Rezultati analize dobiveni su na osnovi analiza uz uporabu paketa računske dinamike fluida FIRE, jednodimenzionalnog modela za izračun karakteristika ubrizgavanja i empirijskih izraza za izračun dimenzija kapljica ubrizganog goriva te dometa mlaza. Kalkulacije su izrađene za konvecionalan sustav ubrizgavanja s linijskom pumpom, visokotlačnim cijevima i mlaznicom sa četiri rupe. Dobiveni rezultati mogu se koristiti za ispravno podešavanje sustava za ubrizgavanje na primjeru uporabe alternativnog goriva umjesto klasičnog dizelskog goriva.Abstract The presented paper discusses the influence of using alternative fuels on the fuel injection process, in-nozzle flow characteristics and spray formation process. The analysis is performed using the computational fluid dynamics package Fire, a one-dimensional mathematical model for the injection process characteristics calculations and empirical models for calculating the injected droplet mean diameter and spray penetration length. The calculations were performed for the conventional fuel injection system with the in-line pump, high pressure tube and four-hole nozzle with the sac chamber. The results of presented analysis can be used to set properly the fuel injection system for operation with alternative fuels

DIESEL AND BIODIESEL MACRO-SPRAY CHARACTERISTICS

Sažetak Karakteristike ubrizgavanja i formiranja mlaza u prostoru izgaranja jedan su od najvažnijih čimbenika modernih dizelovih motora i imaju značajan utjecaj na efektivne parametre i emisije ispuha. U posljednjih nekoliko desetljeća, biodizelu se kao motornom gorivu sve više posvećuje posebna pažnja. Unatoč tome što ima slične fizičke osobine kao dizelsko gorivo, svejedno veća gustoća, viskoznost i površinski napon mogu ponekad prouzročiti anomalije u procesu ubrizgavanja, kao što su npr. dodir mlaza sa stijenkama komore izgaranja, loše miješanje sa zrakom (prevelike kapljice) i drugo. U radu su prikazani rezultati istraživanja fizičkih svojstava dizelskog i biodizelskog goriva glede karakteristika ubrizgavanja i mlaza goriva. Utjecaj fizičkih osobina goriva proučavan je uz pomoć fizičko-matematičkog modela, simuliranjem procesa ubrizgavanja u konvencionalnom sustavu. Model je bio razvijen na IEPOI - Inštitut za energetiko, procesno in okoljsko inženirstvo Fakulteta za strojništvo, Univerza v Mariboru, koda Bkin, provjeren eksperimentalno na uređaju i na motoru. U posebnom smo uređaju izmjerili makro karakteristike mlaza (domet, kut, oblik), dok je vremensko prodiranje mlaza u mirujući zrak praćeno visokobrzinskom kamerom (2500 snimaka/s). Uz pomoć 3D programa (AVL "Fire"), dopunjena za ova istraživanja na IEPOI, mogli smo pratiti procese u motoru i odrediti ostale parametre mlaza (promjer kapljice i njihovu distribuciju u aksijalnom prosjeku) u ovisnosti o vremenu i odrediti njihove integralne prosječne vrijednosti i usporediti ih s vrijednostima dobivenih eksperimentom. U radu su prikazani rezultati utjecaja fizičkih osobina goriva i radnih uvjeta na karakteristike ubrizgavanja i mlaza goriva.Abstract Characteristics of fuel injection and spray formation in the engine combustion chamber are most important factor of up-to-date diesel engines, influencing their effective performance parameters and exhaust emissions. During last few decades alternative automotive fuels, such as biodiesel have received salient attention. Even though it has similar physical properties as diesel fuel, higher density, viscosity and surface tension of biodiesel may have a dominant influence on the spray formation and sometimes cause spray anomalies - such as contact between fuel and combustion chamber, poor mixing with air (bigger fuel droplets) etc. Results of the investigation about the impact of the diesel and biodiesel fuel physical properties on the injection and spray characteristics are presented in the paper. Physical properties of both have been examined and used in the mathematical model of the conventional injection system. The model was derived in IEPO - Institute for Power, Process and Environmental Engineering Faculty of mechanical engineering, University Maribor, simulation code Bkin, and was verified by experiment carried out on the fuel injection system test bench and on the engine. In a special test chamber the macro-characteristics of the spray injected into motionless air at the atmospheric pressure and room temperature (spray penetration distance, angle, and spray shape) have been measured and spray images were recorded by the high-speed camera (2500 frames/s). Using 3D simulation program (AVL "Fire") and including for the purpose of these investigations a few new estimates, the injection process for both fuels have been simulated and compared with the results obtained by experiments. These results are presented and discussed in the paper

Influence of fuel properties on engine characteristics and tribology parameters

U radu se razmatra korištenje mineralnog dizelskog goriva, čistog biodizelskog goriva, te njegovih mješavina i utjecaj svojstava goriva na značajke motora s ciljem smanjenja štetnih emisija. Za eksperimente je korišten autobusni dizelov motor, te čisto biodizelsko gorivo proizvedeno iz repičina ulja i nekoliko njegovih mješavina s mineralnim dizelskim gorivom. Gustoća, viskoznost, površinska napetost i brzina zvuka ispitivanih goriva određivane su eksperimentalno i vrijednosti su uspoređivane s istima od mineralnog dizelskog goriva. Dobivene rezultate smo upotrijebili za analizu najvažnijih značajki motora i triboloških parametara.This paper deals with the mineral diesel, neat biodiesel and their blends and it discusses the influence of fuel properties on the engine characteristics with the aim to reduce harmful emissions. The considered engine is a bus diesel engine. The considered fuels are neat biodiesel from rapeseed oil and some of its blends with mineral diesel. The density, viscosity, surface tension, and sound velocity of tested fuels are determined experimentally and compared to those of mineral diesel. The obtained results are used to analyze the most important engine characteristics and tribology parameters

ENERGY LOSSES IN FUEL INJECTOR

Sažetak Sve stroži zahtjevi glede smanjenih emisija zagađujućih tvari od motornih vozila u cestovnom prometu dovode do zahtjeva za stalnim unapređenjem tehničkih rješenja na motoru, te zahtjeva za korištenjem alternativnih goriva. Primjena alternativnih goriva kod dizelovih motora može biti raznovrsna što dovodi do zaključka o nužnosti kvalitetnog poznavanja značajki goriva i njihovog utjecaja na karakteristike ubrizgavanja. Analizom primjene različitih alternativnih goriva uočeno je da se osnovni pokazatelji procesa ubrizgavanja kao što su: tlak ubrizgavanja, trajanje procesa ubrizgavanja, količina ubrizganog goriva, itd. mijenjaju, što značajno utječe na proces izgaranja u dizelovom motoru. Zbog toga je nužno da se za optimalni proces izgaranja u dizelovom motoru podesi sustav za ubrizgavanje goriva. Posebno interesantno mjesto u sustavu za ubrizgavanje goriva je brizgaljka, gdje se vrši pretvorba potencijalne u kinetičku energiju, uz prisutnost značajnih energetskih gubitaka. Stoga je posebna pažnja posvećena obradi eksperimentalnih rezultata karakteristika ubrizgavanja i nabrojenih osnovnih pokazatelja procesa ubrizgavanja. Nakon provedene analize pristupilo se definiranju energetskih gubitaka u brizgaljci što će biti prezentirano u radu.Abstract New demands regarding reducing emissions of pollutants from motor vehicles in road transport lead to requests for continual improvement of technical solutions of the IC engine on one hand, as well as using of alternative fuels on the other. Application of alternative fuels in IC diesel engines could be different and it makes a conclusion based on necessity of well knowing fuel characteristics and its influences on injection characteristics. Based on analysis of different used alternative fuels, it has been noticed that basic parameters of fuel injection process, like injection pressure, injection duration, fuel injected amount, etc. were changed, influencing combustion process in the IC diesel engine. According to these facts, in order to make an optimal combustion process in the IC diesel engine, it is necessary to set up fuel injection system. A special part of fuel injection system is the injector, where transformation from potential to kinematic energy of fuel is conducted, with significant energy losses. Therefore special attention was dedicated to processing experimental results, first of all to shape the injection rate, as well as other mentioned injection characteristics. After analysis, a definition of energy losses in the injector was done and presented in the paper

INFLUENCE OF BIOFUELS ON DIESEL ENGINE PERFORMANCE

Smanjenje emisije toksičnih tvari iz ispušnih plinova dizelovih motora s unutarnjim izgaranjem načelno gledajući moguće je ostvariti na tri mjesta: ispred motora, u samom motoru i iza motora s unutarnjim izgaranjem, sui. Uobičajeno je to izvesti uvođenjem katalizatora na ispušnom sustavu, upravljanjem procesima izmjene radnih tvari, pripremom gorive smjese i samog procesa izgaranja, kao i korištenjem goriva koja po svom kemijskom sastavu imaju potencijal za redukciju. Posljednja u ovom nizu navedena opcija izgleda najjednostavnija, ali ne predstavlja nešto što se samo po sebi podrazumijeva. Zbog različitih svojstava goriva neophodno je izvršiti optimiziranje pojedinih sustava na motoru s unutarnjim izgaranjem jer u protivnom mogu izostati u jednoj krajnosti željeni efekti smanjenja emisije toksičnih tvari, a u drugoj krajnosti može doći do neprihvatljivih radnih performanci samog motora. U okviru rada razmatrana je uporaba biogoriva u obliku repičinog metil estera – biodizela s aspekta performanci i potrebe za optimiranjem pojedinih sustava na motoru sui, kao preduvjeta za efektivno korištenje biogoriva kao jedinog goriva, te mogućnost optimiranja sustava na motoru kako bi se ostvarile relativno najbolje moguće performance za slučaj korištenja i fosilnog dizelskog goriva kao i biogoriva.In principle, emission reduction of toxic substances in exhaust gas of IC diesel engines can be achieved at three places: before, in and after the IC engine. The common approach is the introduction of catalytic exhaust systems, valve timing, fuel mixture preparation and combustion modeling, as well as using fuels the chemical composition of which provides the potential for reduction. The latter option seems to be the simplest, but it is not necessarily the first option that would be taken into consideration. Due to the different properties of fuels, it is necessary to optimize individual systems of the internal combustion engine; otherwise, it may happen that the reduction of emissions of toxic substances is absent as a desired effect, or, in the opposite extreme, unacceptable performance of the engine may result. This paper provides an elaboration on the use of bio fuels in the form of rapeseed methyl esters - bio diesel, in terms of performance and the need for optimization of individual systems on internal combustion engines. That is a precondition for the effective use of bio fuels as the only fuel, and there is also a possibility of optimizing the engine system in order to achieve the best possible relative performance in case both fossil fuel and bio fuel are used

INFLUENCE OF VARIOUS MESH TYPES ON CAVITATION PHENOMENA IN THE INJECTION NOZZLE

Isparivost dizelskog goriva u otvoru mlaznice u velikoj mjeri utječe na značajke ubrizgavanja i formiranja mlaza. U radu se analizira utjecaj različitih tipova mreže na procese kavitacije. Budućid da je CPU (Centralna Procesorska Jedinica) vremena često dugačka, u analizi su korišteni parcijalni modeli. Numeričku analizu izvodili smo za dvije vrste tekućina, dizel (D2) i biodizel (B100), koristeći računski program FIRE za dinamiku fluida (CFD). Rezultati su uspoređivani za razne tipove mreže za obje vrste goriva i pokazuju da veće razlike u tlaku uzrokuju veću kavitaciju u otvoru sapnice brizgaljke te ističu važnost strukture i gustoće mreže.The evaporation of diesel fuel in the injection nozzle influences the injection characteristics and spray formation process significantly. In the presented paper the influence of various type of mesh on the cavitation phenomena is analysed. Since CPU (central processing unit) times are often high, partial models are used for the analysis. The numerical analysis is made for two types of fluid, diesel (D2) and biodiesel (B100), using computation fluid dynamic (CFD) program FIRE. The results are compared for various meshes and both types of fuel. The results show that higher pressure differences yield more cavitation in the injector nozzle holes and point out the importance of the structure of the mesh and its density

IMPROVEMENT OF ECOLOGICAL PERFORMANCE OF DIESEL ENGINES BY USING MIXTURES OF CONVENTIONAL FOSSIL FUELS AND BIODIESEL

Uporaba goriva iz obnovljivih izvora energije nije više stvar opredjeljenja pojedinaca da na lokalnoj razini osobnim primjerom doprinesu smanjenju emisije zagađujućih tvari iz ispuha cestovnih vozila, već sveobuhvatna strategija i temelj unapređenja i razvoja globalnog energetskog sektora i ciljani doprinos smanjenju zagađenja okoliša. Kako bi se podcrtao značaj takvih opredjeljenja, u okviru međunarodnih sporazuma jasno se navode ciljevi koji se žele postići u budućnosti. Međutim, pri postavljanju ciljeva u pogledu povećanja obujma korištenja biodizela, treba voditi računa o dostupnosti takvog goriva i o mogućnosti njegove primjene u postojećem voznom parku. Budući da su izvori sirovine i tehnologije za dobivanje biodizela još uvijek na takvoj razini da ne mogu pokriti potrebe cjelokupnog tržišta, a i vozni park je prvenstveno prilagođen za korištenje konvencionalnog fosilnog goriva, prijelazno rješenje je upravo korištenje mješavine ova dva goriva. U okviru ovog rada razmatrana je uporaba mješavine konvencionalnog fosilnog dizel goriva i biodizela u dizelovim motorima s unutarnjim izgaranjem (SUI) namijenjenih za putna vozila. Analizirani su trendovi promjene energetskih (snaga, moment, specifična potrošnja goriva) i ekoloških (emisija zagađujućih tvari) performansi dizelovih motora u ovisnosti o postotnom udjelu biodizela u mješavini goriva.The use of fuels from renewable energy sources is no longer a matter of individual commitment to reduce emissions contributing to air pollution from exhausts of road vehicles, but a matter of comprehensive strategy to improve the foundation and development of the global energy sector, and to provide a targeted contribution to the reduction of environmental pollution. Underlying the importance of this determination, the framework of international agreements clearly states certain objectives to be achieved in the future. However, when setting targets for increasing the scope of use of biodiesel, it is important to take into account the availability of such fuel, as well as the possibilities of its application in the existing vehicle fleet. Given the fact that sources of raw feedstock and the technology for obtaining biodiesel are still at the level that cannot cover the needs of the entire market, coupled with the fact that the existing vehicle fleet is primarily suited for the use of conventional fossil fuels, using a mixture of these two fuels can be an interim solution. This paper considers the use of fuel blends of conventional fossil diesel fuel and bio diesel in diesel-powered internal combustion engines designed for on-road applications. It analyzes the trends of energy performance (power; torque; specific fuel consumption) and environmental properties of diesel engines (emissions of polluting substances), depending on the percentage of bio diesel in fuel blends

INFLUENCE OF ALTERNATIVE FUELS ON COMBUSTION INDICATORS WITH DIESEL ENGINES

Sažetak Svakodnevno smanjivanje prirodnih rezervi goriva fosilnog porijekla, kao i neprestani porast troškova njihove eksploatacije uvjetuje sve intenzivnija istraživanja o mogućim alternativnim izvorima energije koji bi s jedne strane smanjili ovisnost o uvozu skupe sirove nafte i njezinih proizvoda, a ujedno doprinijeli smanjenju emisije toksičnih tvari koje se oslobađaju njezinim izgaranjem. Kao rezultat takvog razmišljanja većina razvijenih industrijskih zemalja u Europi nastoji ispuniti prijedlog Europskog parlamenta i Vijeća za promicanje uporabe biogoriva, u kojem se predlaže postupna zamjena benzina i dizelskog goriva u iznosu od 5,75 % od njihovih ukupno prodanih količina s biogorivima, mjereno po njihovom energetskom sadržaju, do 2010. godine. U okviru ovog rada razmatrana je uporaba biogoriva u dizelovim motorima s unutarnjim izgaranjem namijenjenih za pogon motornih vozila i strojeva. Akcent je stavljen na proces izgaranja tzv. biodizel goriva, kao potpune zamjene klasičnom dizelskom gorivu, te njegovih mješavina s njim, gdje vrlo važnu ulogu ima početak, karakter oslobađanja topline i vrijeme trajanja procesa izgaranja. Prikazani su rezultati proračuna relevantnih parametara procesa izgaranja tako dobivenih goriva, kao i njihova usporedba s odgovarajućim parametrima izgaranja dizelskog goriva fosilnog porijekla. Rezultati provedenih proračuna su verificirani namjenskim ispitivanjima na konkretnom dizelovom motoru.Abstract Constant lowering of natural reserves of fossil fuels as well as continuous increasing of its exploitation costs influences more intensive researching in finding alternative energy recourses that are able to decrease an import dependent of expensive raw oil and its products from one side and give contribution to decreasing toxic emission as a product of combustion process. As result of this consideration majority of developed European countries endeavor to fulfill proposals of the European parliament and the Council for promotion bio fuels to substitute petroleum and diesel fuels with bio fuels in proportion of 5.75% of their total sold amount, measured by its energy content, by the year 2010. In the paper usage of bio fuels in IC diesel engines for mobile applications is considered. Accent is given on combustion processes of so called biodiesel fuel, as a full alternative for classical diesel fuel, as well as their blends, where important role has beginning, character of heat release and duration of combustion process. Calculation results of relevant combustion parameters for the used fuels and comparison with appropriate parameters of combustion processes with fossil origin based diesel fuel are presented. Verification of the calculation results where carried out through tests made on one diesel engine