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2. Black-out diesel engine operation modelling for the CHPP start-upDušan Strušnik, Marko Agrež, Jurij Avsec, 2022, published scientific conference contribution Abstract: Modelling power plants using real process data is crucial in determining the cost-effectiveness and flexibility of systems. The quality of the elaborated model is determined with the validation of the model, which can also give results for the operating regimes of the plant, which are not often used in practice. In this way, also the operation and responsiveness of power plants outside the range of planned operation are determined. The model simulates the operation of a diesel engine (DE) required to start a combined heat & power plant (CHPP) from a black-out or loss of the electrical power network supply. The model is made on the basis of data provided by the manufacturer and the measured DE data. The results of the model enable detailed insight into the characteristics of the DE behaviour at different operating regimes. The economic and ecological rationale ranges of operation of the DE can be determined from the characteristics of operation. The results of the model show that the DE operates with a 41.72% average efficiency, consumes from 0.114 kg/s of diesel fuel for its operation and up to 3.68 kg/s of air, the air ratio ranges from 2.2 to 2.5. DE develops shaft power up to 2170 kW.
Keywords: air-fuel equivalence ratio, black-out, diesel engine, thermal efficiency, shaft power
Published in DKUM: 27.10.2023; Views: 530; Downloads: 8
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3. Methodology improvements to simulate performance and emissions of engine transient cycles from stationary operating modes: A case study applied to biofuelsFernando Cruz-Peragón, Eloisa Torres Jiménez, Luka Lešnik, Octavio Armas, 2022, original scientific article Abstract: In the present study engine/vehicle responses from a standardized transient test cycle are estimated using 13 stationary operating regimes following a previously developed methodology. The main advantage of the methodology tested is that allows obtaining an estimation of transient parameters in a stationary test bench, which requirements are much less demanding than those of the transient test bench. The objectives are: in one hand, to demonstrate that the methodology correctly estimates engine responses regardless of the fuel tested, as it is proposed in a previous paper and, on the other hand, to improve the methodology and the accuracy of the estimated parameters. The fuels tested are renewable fuels from different raw materials (biodiesel from rapeseed, sunflower, and soybean), and diesel fuel as the reference. Biodiesels were tested neat and blended (30% v/v) with diesel fuel. The engine is a common-rail light-duty one, and the standardized testing procedure used to illustrate the implementation of the methodology is the New European Driving Cycle (NEDC). Two design of experiments (DoE) of 13 runs each were analyzed. One of the DoE tested was proposed for characterizing the NEDC, referred as to CTDoE design, while the other one is a five-level fractional factorial design (FFDoE) that adequately matches the optimality criteria of orthogonality, D-optimal criterion, rotatability, and space-filling. The original methodology was improved by the implementation of a new fitting function that simulates the cold start effect over the engine parameters and by an new definition of the boundary in the [n,M] domain. These improvements showed significantly higher accuracy of the estimated engine parameters obtained, both instantaneous and accumulated, respect to the original methodology. The results obtained based on the application of the FFDoE design support the feasibility of the methodology tested. Engine performance and regulated emissions responses, such as intake air and fuel mass flow rate, thermomechanical exergy rate, exhaust gas residual heat rate, total hydrocarbons (THC), nitrogen oxides (NOx), carbon monoxide (CO) and particulate matter (PM) emissions from a transient test were instantaneously and cumulatively predicted with high accuracy using the engine responses from 13 steady-state operating modes.
Keywords: simulation, light duty diesel engine, transient cycle, biodiesel, design of experiments, cold start correction function
Published in DKUM: 21.09.2023; Views: 350; Downloads: 30
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4. Experimental investigation review of biodiesel usage in bus diesel engineBreda Kegl, Marko Kegl, 2017, original scientific article Abstract: This paper assembles and analyses extensive experimental research work conducted for several years in relation to biodiesel usage in a MAN bus Diesel engine with M injection system. At first the most important properties of the actually used neat rapeseed biodiesel fuel and its blends with mineral diesel are discussed and compared to that of mineral diesel. Then the injection, fuel spray, and engine characteristics for various considered fuel blends are compared at various ambient conditions, with special emphasis on the influence of low temperature on fueling. Furthermore, for each tested fuel the optimal injection pump timing is determined. The obtained optimal injection pump timings for individual fuels are then used to determine and discuss the most important injection and combustion characteristics, engine performance, as well as the emission, economy, and tribology characteristics of the engine at all modes of emission test cycles test. The results show that for each tested fuel it is possible to find the optimized injection pump timing, which enables acceptable engine characteristics at all modes of the emission test cycles test.
Keywords: bus diesel engine, fuel injection, fuel spray, combustion, emission, engine performance, tribology characteristics, optimized injection pump timing
Published in DKUM: 07.07.2017; Views: 1657; Downloads: 417
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5. Sensor for injection rate measurementsMilan Marčič, 2006, original scientific article Abstract: A vast majority of the medium and high speed Diesel engines are equipped with multi-hole injection nozzles nowadays. Inaccuracies in workmanship and changing hydraulic conditions in the nozzles result in differences in injection rates between individual injection nozzle holes. The new deformational measuring method described in the paper allows injection rate measurement in each injection nozzle hole. The differences in injection rates lead to uneven thermal loads of Diesel engine combustion chambers. All today known measuring method, such as Bosch and Zeuch give accurate results of the injection rate in diesel single-hole nozzles. With multihole nozzles they tellus nothing about possible differences in injection rates between individual holes of the nozzle. At deformational measuring method, the criterion of the injected fuel is expressed by the deformation of membrane occurring due to the collision of the pressure wave against the membrane. The pressure wave is generated by the injection of the fuel into the measuring space. For each hole of the nozzle the measuring device must have a measuring space of its own into which fuel is injected as well as its measuring membraneand its own fuel outlet. During measurements procedure the measuring space must be filled with fuel to maintain an overpressure of 5 kPa. Fuel escaping from the measuring device is conducted into the graduated cylinders for measuring the volumetric flow through each hole of the nozzle.The membrane deformation is assessed by strain gauges. They are glued to the membrane and forming the full Wheatstonećs bridge. We devoted special attention to the membrane shape and temperature compensation of the strain gauges.
Keywords: thermodynamics, sensors, Diesel engines, nozzles, injection, measurements
Published in DKUM: 22.06.2017; Views: 1812; Downloads: 349
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7. Koriščenje odpadne toplote iz motorjev z notranjim izgorevanjemAljaž Knavs, 2017, master's thesis Abstract: V magistrskem delu je opisano pridobivanje električne energije iz odpadne toplote motorja z notranjim zgorevanjem. Magistrsko delo vsebuje preračune izgub dizelskega motorja preko izgorelih plinov. Preračuni se nanašajo na tovorno vozilo, kjer je poraba goriva večja od osebnih vozil. Sistem se izplača le v primerih, kadar imamo toplotni stroj z veliko porabo in s konstantnim delovanjem. Na voljo imamo več sistemov koriščenja odpadne toplote, iz Peltierjevega modula, Stirlingovega motorja itd., vendar je v magistrskem delu za preračune uporabljen izključno turbinski model. Za samo proizvodnjo električne energije je najbolj primeren turbinski sistem prav zaradi boljših karakteristik delovanja, vendar potrebuje relativno konstanten doprinos toplotne energije.
Keywords: Diesel motor, motor z notranjim zgorevanjem, odpadna toplotna energija, avtomobilska industrija
Published in DKUM: 11.05.2017; Views: 2807; Downloads: 133
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9. Numerical and experimental study of water/oil emulsified fuel combustion in a diesel engineNiko Samec, Breda Kegl, Robert W. Dibble, 2002, original scientific article Abstract: Numerical and experimental studies were made on some of the chemical and physical properties of wateržoil emulsified fuel (W/OEF) combustion characteristics. Numerical investigations of W/OEF combustion's chemical kinetic aspects have been performed by simulation of water/n-heptane mixture combustion, assuming a model of a homogenous reactor's concentric shells. The injection and fuel spray characteristics are analyzed numerically also in order to study indirectly the physical effects of water present in diesel fuel during the combustion process. The experimental results of W/OEF combustion in the DI diesel engine are also presented and discussed. The results of engine testing in a broad field of engine loads and speeds have shown a significant pollutant emission reduction with no worsening of specific fuel consumption.
Keywords: internal combustion engines, Diesel engines, combustion, emissions, numerical modelling
Published in DKUM: 01.06.2012; Views: 2356; Downloads: 116
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10. Effects of biodiesel on emissions of a bus diesel engineBreda Kegl, 2008, original scientific article Abstract: This paper discusses the influence of biodiesel on the injection, spray, and engine characteristics with the aim to reduce harmful emissions. The considered engine is a bus diesel engine with injection M system. The injection, fuel spray, and engine characteristics, obtained with biodiesel, are compared to those obtained with mineral diesel (D2) under various operating regimes. The considered fuel is neat biodiesel from rapeseed oil. Its density, viscosity, surface tension, and sound velocity are determined experimentally and compared to those of D2. The obtained results are used to analyze the most important injection, fuel spray, and engine characteristics. The injection characteristics are determined numerically under the operating regimes, corresponding to the 13 mode ESC test. The fuel spray is obtained experimentally under peak torque condition. Engine characteristics are determined experimentally under 13 mode ESC test conditions. The results indicate that, by using biodiesel, harmful emissions (NOx, CO, smoke and HC) can be reduced to some extent by adjusting the injection pump timing properly.
Keywords: biodiesel, bus diesel engine, emissions
Published in DKUM: 01.06.2012; Views: 1452; Downloads: 88
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