This thesis deals with braking effect of the truck’s engine. The theoretical part introduces the reader to the basic construction of trucks, describes most using engine and defines the factors having a significant effect on engine braking. In the practical part the reader is familiar with the technique used in making the measurement and description of the vehicle chosen for the implementation of measurement. The result of the practical part is the values obtained by measurement including their interpretation contained in the conclusion.

This diploma thesis is focused on examining the development of a diesel tractor engine with a newer injection system, concretely common-rail system. Mainly it is about the application of the high pressure fuel pump, fuel rail and injectors. With regard to the used components are appropriate adjustments made on the engine, and then checked using the available calculations. Brief mention is given to the theoretical summary of the contemporary state of applied injection system and its development trend. Selecting adjustments is primarily based on observed operating load. However, it is also striving to their simplest implementation. An integral part of this work is drawing documentation of newly designed components.

To meet the constantly restricting emission regulations and develop better strategiesfor engine control systems, thorough knowledge of engine behavior is crucial.One of the characteristics to evaluate engine performance and its capabilityfor power generation is in-cylinder pressure. Indeed, most of the diagnosis andcontrol signals can be obtained by recording the cylinder pressure trace and predictingthe thermodynamic variables [3].This study investigates the correlation between the in-cylinder pressure andtotal trapped gas mass [10] with the main focus on estimating the in-cylinder gasmass as a part of a lab measuring procedure using the in-cylinder pressure sensors,or as a real-time method for implementation in an engine control unit thatare not equipped with the cylinder pressure sensors. The motivation is that precisedetermination of air mass is essential for the fuel control system to convey themost-efficient combustion with lower emissions delivered to the after-treatmentsystem [10].For this purpose, a six-cylinder Diesel engine is used for recording the enginespeed, engine torque, measuring the cylinder pressure profile resolved bythe crank angle, intake and exhaust valve phasing as well as intake and exhaustmanifold pressures and temperatures. Next, the most common ways of estimatingthe in-cylinder trapped gas mass are studied and the most reliable ones areinvestigated in-depth and a model with the acceptable accuracy in different operatingconditions is proposed, explained and implemented. The model in has athermodynamics basis and the relative errors is lower than 3% in all the investigatedtests. Afterwards, the most important findings are highlighted, the sourcesof errors are addressed and a sensitivity analysis is performed to evaluate themodel robustness. Subsequently, method adjustment for other operating conditionsis briefly explained, the potential future work is pointed and a complete setof results is presented in Appendix B.

Current trends in diesel transport anticipate that in the upcoming future a range of renewable fuels will be necessary to comply with emission and sustainability legislations. Exhaust after-treatment devices such as diesel particulate filters –DPFs– will have to operate satisfactorily with this pool of biofuels. In particular, DPF regeneration is crucial to cut the fuel penalty and guarantee an acceptable lifetime for this device. In the present work, an automotive diesel engine was run with fossil fuel and three renewable fuels: a conventional biodiesel, a fuel manufactured through Fischer-Tropsch –FT– process and a HVO biofuel. The DPF was loaded and regenerated through an active process with fuel post-injections. Additionally, soot samples were investigated with thermo-gravimetry (TGA) and calorimetry (DSC) to confirm whether these techniques obtain relevant information for explaining DPF behavior. Both methods proved that biodiesel leads to a more economical regeneration being the biodiesel soot, more reactive than the other samples, the main reason. DPF regenerations with paraffinic fuels (FT-derived and HVO) did not reveal strong differences compared to diesel, though TGA and DSC results suggested that soot from paraffinic biofuels is more reactive than that from diesel. The exhaust gas temperature and composition are behind this apparent discrepancy.

De ökande luftföroreningarna i Europa är ett allvarligt miljöproblem, och vägtransporterna är en av de största orsakerna till detta. För att ta itu med detta problem och uppfylla nya utsläppskrav måste efterbehandlingssystemen för avgaser förbättras. Det är viktigt att förstå sammansättningen, egenskaperna och mängden partiklar (PM) som produceras av dieselmotorer för att kunna minska partikelutsläppen med dieselpartikelfiltret (DPF). Denna studie ger en djupgående analys av partikelutsläpp från tunga dieselmotorer, med fokus på att förstå källorna till partikelutsläpp, deras inverkan på partikelns struktur och reaktivitet. Olika filter för att samla in partiklarna användes och analyserades. Dessutom utvecklades och diskuterades en extraktionsmetod för att avlägsna partiklarna från filtren. Förhållandet mellan aska och sot samt kinetiska oxidationsparametrar har undersökts för flera prover från sex- och åttacylindriga motorer under olika driftscykler. Morfologiska egenskaper hos aska och sot undersöktes med SEM. Askfraktionen uppskattades ligga mellan 3 och 23 procent av den totala PM-sammansättningen. Askans elementära sammansättning undersöktes med hjälp av EDS och ICP. Viktförlustkurvor erhölls med TGA och de kinetiska parametrarna för sotoxidation beräknades med den icke-isotermiska metoden. Aktiveringsenergierna, som befanns ligga i intervallet 145-162 kJ/mol, visade att alla de testade sotproverna hade en liknande reaktivitet. Ytterligare studier behövs för att förbättra insamlings- och analysmetoderna för att uppnå tillförlitliga resultat. / The rise in air pollution in Europe is a pressing environmental health concern, and road transport is a major contributor. To address this issue and meet new emission standards, exhaust aftertreatment systems must be improved. Understanding the composition, properties, and amount of particulate matter (PM) produced by diesel engines is critical for reducing PM emissions with the diesel particulate filter (DPF). This research provides an in-depth analysis of PM emissions produced by heavy-duty diesel engines, with focus on understanding the sources of PM emissions, their impact on the structure and on the reactivity of the PM. Various filters to collect the particulate were employed and critically analysed. Furthermore, an extraction procedure to remove the PM from the filters was developed and discussed. Ash to soot ratio and kinetic oxidation parameters have been investigated for several samples deriving from 6-cylinder and 8-cylinder engines during different operational cycles. Morphological features of ash and soot were investigated with SEM. The ash fraction was estimated to lie between 3 and 23 percent in the total PM composition. Ash elemental composition was carried out through EDS and ICP. Weight loss curves were obtained with TGA and the soot oxidation kinetic parameters were calculated with the non-isothermal multiple-ramp rates method. The activation energies, which were found to be in the range of 145-162 kJ/mol, demonstrated that all of the soot samples tested had a similar reactivity. Further studies are needed to improve the collection and analysis methods in order to achieve reliable results.

Recent imaging studies have provided a new conceptual model of the internal structure of direct injection diesel fuel jets as well as empirical correlations predicting jet development and structure. This information was used to create a diesel cycle simulation model using C language including compression, fuel injection and combustion, and expansion processes. Empirical relationships were used to create a new mixing-limited zero-dimensional model of the diesel combustion process. During fuel injection five zones were created to model the reacting fuel jet: 1) liquid phase fuel 2) vapor phase fuel 3) rich premixed products 4) diffusion flame sheath 5) surrounding bulk gas. Temperature and composition in each zone is calculated. Composition in combusting zones was calculated using an equilibrium model that includes 21 species. Sub models for ignition delay, premixed burn duration, heat release rate, and heat transfer were also included. Apparent heat release rate results of the model were compared with data from a constant volume combustion vessel and two single-cylinder direct injection diesel engines. The modeled heat release results included all basic features of diesel combustion. Expected trends were seen in the ignition delay and premixed burn model studies, but the model is not predictive. The rise in heat release rate due to the diffusion burn is over-predicted in all cases. The shape of the heat release rate for the constant volume chamber is well characterized by the model, as is the peak heat release rate. The shape produced for the diffusion burn in the engine cases is not correct. The injector in the combustion vessel has a single nozzle and greater distance to the wall reducing or eliminating wall effects and jet interaction effects. Interactions between jets and the use of a spray penetration correlation developed for non-reacting jets contribute to inaccuracies in the model.

京都大学 / 新制・課程博士 / 博士(エネルギー科学) / 甲第24253号 / エネ博第451号 / 新制||エネ||84(附属図書館) / 京都大学大学院エネルギー科学研究科エネルギー変換科学専攻 / (主査)教授 川那辺 洋, 教授 林 潤, 教授 澄川 貴志 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DFAM

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Aleksandro Stulginskio Universitete, Transporto ir Jėgos Mašinų Inžinerijos Institute, atliktais tyrimais nustatyta, kad vieno cilindro tiesioginio įpurškimo dyzelinis variklis (,,Oruva“ F1L511) maitinamas pagerintu, 0,08; 0,12; 0,20vol% cetaninį skaičių (CS) didinančiu priedu, rapsų aliejumi (RA), gali efektyviai veikti ir išskirti mažesnę, kai kurių emisijos komponentų dalį. Dyzelinio variklio išvystytas didžiausias efektyvusis slėgis siekė 0,57MPa, varikliui veikiant 2000 min-1 sūkių dažniu. Variklio minimaliosios lyginamosios efektyviosios degalų sąnaudos sumažėjo nuo 272g/kWh iki 268g/kWh tai yra 1,5% panaudojus 0,12vol% cetaninį skaičių didinantį priedą rapsų aliejuje. Deginių dūmingumas sumažėjo 45% vidutinės (pe=0,4MPa) ir 40% didžiausios (pe=0,57MPa) apkrovos srityje atitinkamai panaudojus 0,12vol% ir 0,20vol% cetaninį skaičių didinantį priedą rapsų aliejuje. Bandymų metu didžiausias ƞe=0,364 variklio efektyvusis naudingumo koeficientas buvo pasiektas variklį maitinant 0,12vol% cetaninį skaičių didinančiu priedu apdorotu rapsų aliejumi ir jam išvysčius 5,3 kW efektyviąją galią. Tačiau mažesnės ir didesnės variklio išvystomos efektyviosios galios srityse aukštesnis variklio efektyvusis naudingumas buvo bazinio rapsų aliejaus naudojimo atveju. / Studies conducted at Aleksandas Stulginskis University (ASU) of Transport and Power Machinery Engineering Institute showed that a single-cylinder, air-cooled, direct-injection diesel engine (" Oruva " F1L511 ) can be with rapeseed oil treated with 0.08vol%, 0.12vol% and 0.20vol% the cetane number (CN) improving agent. Diesel engine developed the maximum effective pressure of 0.57MPa when running at 2000 rpm speed. Using of 0.12vol% of the cetane number improving agent (2-ethylheksyl-nitrate) to rapeseed oil the brake specific fuel consumption reduced in the range 272 g/kWh to 268 g/kWh, i.e. 1.5% when running at moderate (pe=0.38MPa) load and 2000 rpm speed. As a result of 0.12vol% the smoke opacity decreased by 45% at moderate (pe=0.4MPa) and 40% at maximum (pe=0.57MPa) load. During the tests, the highest ƞe=0.364 effective efficiency engine was when running on rapeseed oil treated with 0.12vol% cetane improving agent developed at the power output of 5.3 kW.