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61.
Influence of biodiesel fuel on the combustion and emission formation in a direct injection (DI) Diesel engine
Aleš Hribernik, Breda Kegl, 2007, original scientific article

Abstract: This paper studies the influence of biodiesel fuel on the combustion and emission formation of two different direct-injected diesel engines, both employing different combustion processes. The research was focused on determining the influence of the specific combustion process on measurement results to ascertain if a generalization of the results is possible or whetherthey have to be interpreted as specific for specific engines. Standard D2 diesel fuel and commercial 100% biodiesel fuel were used. Tests were executed using both fuels under the same conditions, and exhaust emissions andengine performance were measured and compared. In-cylinder pressure was also acquired, and the rate of heat release curves were computed by means of azero-dimensional, one-zone combustion model. Some macroparameters of the combustion process were obtained from the heat-release-rate curves. The results obtained for both engines showed that findings regarding the influenceof biodiesel fuel on the combustion process and emission formation could not be generalized and had to be interpreted as specific for the particular engine.
Keywords: internal combustion engines, diesel engines, biodiesel fuel, combustion, emissions
Published: 31.05.2012; Views: 976; Downloads: 38
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Investigation into the effect of different fuels on ignition delay of M-type diesel combustion process
Dževad 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: 31.05.2012; Views: 979; Downloads: 168
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Performance and exhaust emissions of an indirect-injection (IDI) diesel enginewhen using waste cooking oil as fuel
Aleš 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: 31.05.2012; Views: 909; Downloads: 41
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Eksperimentalno in numerično raziskovanje nestacionarnega tokovnega polja okoli osamljenega krila
Matej Fike, Gorazd Bombek, Aleš Hribernik, 2011, published scientific conference contribution

Abstract: V članku je predstavljena raziskava vpliva turbulentnega modela na izračunano tokovno polje osamljenega krila v majhnem vetrovniku. Medsebojno so bili primerjani numerični in eksperimentalni rezultati preko točke odcepitve, tlačnega poteka po krilu in tokovnega polja vključno z oscilacijami hitrosti pri obtekanju. Eksperimentalni podatki so bili zajeti s pomočjo tlačnih senzorjev in PIV (Particle Image Velocimetry) merilnega sistema. Raziskava je bila opravljena za različne napadne kote.
Keywords: ventilatorji, vetrovnik, PIV merilni sistem, tokovna hitrostna polja
Published: 01.06.2012; Views: 1091; Downloads: 30
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70.
Velocity measurements in a shotblasting machine
Aleš Hribernik, Gorazd Bombek, Ivan Markočič, 2003, original scientific article

Abstract: Abrasive shotblasting particles and a high concentration of dust within the closed testing chamber make particle velocity measurement in a shotblasting machine very difficult. The application of non-obstructive optical methods is usually impossible. Robust shields protecting the sensors from abrasion have to be used for contacting velocity measurements and make direct application of capacitive or electrodynamic sensors usually applied in the correlation-based velocity measurements methods not possible. An alternative electronic measurement system has been developed. It has a simple construction and uses low cost elements which can be replaced very quickly and, therefore, no robust shields are necessary. This enables very good mobility and positioning of the sensor along both axis in a cross-section plane of a particle stream. The system has been tested along with a robust mechanical measuring device. The development, operation and application of mechanical and electronic particle velocity measurement system are described in this paper. Experimental results are presented, discussed and both methods are compared.
Keywords: shotblasting machines, velocity measurements, particle velocity, mechanical measuring devices, electronic measuring systems
Published: 01.06.2012; Views: 932; Downloads: 37
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