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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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6. 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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7. Performance and exhaust emissions of an indirect-injection (IDI) diesel enginewhen using waste cooking oil as fuelAleš Hribernik, Breda Kegl, 2009, original scientific article Abstract: A study was carried out on the influence of waste cooking oil (WCO) and its blends with D2 fuel on the performance, exhaust emissions, combustion and fuel injection processes of an indirect injected diesel engine. Tests were carried out using different fuels, under the same conditions. Exhaust emissions and engine performance were measured and compared. Combustion chamber pressure was also acquired, and the rate of heat-release curves were computed by means of a zero-dimensional one-zone combustion model. Some macro-parameters of the combustion process were obtained from the heat-release-rate curves. The injection system was separated from the engine and tested on a special test bench. The injected fuel quantity was measured, and the injection pressure and injector needle lift time history were acquired. The injection-rate curves were then computed, and some macro-parameters of the injection process were obtained and analyzed.
Keywords: diesel engine, waste cooking oil, exhaust emissions
Published in DKUM: 31.05.2012; Views: 1812; Downloads: 171
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8. Influence of biodiesel on injection, fuel spray, and engine characteristicsBreda Kegl, Stanislav Pehan, 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 under peak torque and ratedconditions. 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 mineral diesel. The experimentally obtained results are used to analyze the most important injection, fuel spray, and engine characteristics. Furthermore, the influence of biodiesel usage on lubrication is presented briefly. The results indicate that, by using biodiesel, harmful emissions (NOx, CO, HC, smoke, and PM) can be reduced to some extent by adjusting the injection pump timing properly while keeping other engine characteristics within acceptable limits. Furthermore, the results indicate better lubrication conditions when biodiesel is used.
Keywords: biodiesel, diesel engine, injection characteristics, fuel spray, emission, lubrication
Published in DKUM: 31.05.2012; Views: 1954; Downloads: 396
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9. Investigation into the effect of different fuels on ignition delay of M-type diesel combustion processDževad Bibić, Ivan Filipovič, Aleš Hribernik, Boran Pikula, 2008, original scientific article Abstract: An ignition delay is a very complex process which depends on a great number of parameters. In practice, definition of the ignition delay is based on the use of correlation expressions. However, the correlation expressions have very often limited application field. This paper presents a new correlation which has been developed during the research project on the direct injection M-type diesel engine using both the diesel and biodiesel fuel, as well as different values of a static injection timing. A dynamic start of injection, as well as the ignition delay, is defined in two ways. The first approach is based on measurement of a needle lift, while the second is based on measurement of a fuel pressure before the injector. The latter approach requires calculation of pressure signals delay through the fuel injection system and the variation of a static advance injection angle changing. The start of a combustion and the end of the ignition delay is defined on the basis of measurements of an in-cylinder pressure and its point of separation from a skip-fire pressure trace. The developed correlation gives better prediction of the ignition delay definition for the M-type direct injection diesel engine in the case of diesel and biodiesel fuel use when compared with the classic expression by the other authors available in the literature.
Keywords: ignition delay, diesel engine, M-type, biodiesel
Published in DKUM: 31.05.2012; Views: 1702; Downloads: 372
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10. Optimization of a fuel injection system for diesel and biodiesel usageBreda Kegl, Marko Kegl, Stanislav Pehan, 2008, original scientific article Abstract: This paper presents an optimization procedure of a fuel injection system of a bus diesel engine. Attention is focused on the differences resulting from using two different types of fuel: diesel and biodiesel. The proposed design procedure relies on the assumption that the atomization of fuel spray influences the diesel engine performance, fuel consumption, and harmful emission significantly. As a measure of spray atomization, the Sauter mean diameter is employed and introduced into the objective function. The design problem is formulated in the form of a multiobjective optimization problem, taking into account the ESC 13 mode test for diesel engines of commercial vehicles. The design variables of the injection system are related to the shape of the cam profile, to the nozzle geometry, and to the control parameters influencing the injection quantity and timing. The geometrical properties of the cam profile and the injection parameters are kept within acceptable limits by the imposed constraints. The results of optimization using diesel and biodiesel are compared to each other to show the influence offuel type on final design and performance of the system.
Keywords: fuel injection system, diesel engine, biodiesel fuel, engine performance, numerical simulations
Published in DKUM: 31.05.2012; Views: 2544; Downloads: 92
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