Effect of bio fuels (FAME) on the coking level in diesel engine injectors / Jerzy Cisek, Andrzej Mruk // Technológ [Dokument elektroniczny]. – Dysk optyczny CD. – 2011, R. 3, Nr 3, 10 s. : il. (w ... więcej

Effect of bio fuels (FAME) on the coking level in diesel engine injectors / Jerzy Cisek, Andrzej Mruk // Technológ [Dokument elektroniczny]. – Dysk optyczny CD. – 2011, R. 3, Nr 3, 10 s. : il. (w tym kolor.). – Oznaczenie ref./art.: Cisek Jerzy_Mruk Andrzej.pdf. – Bibliogr. 7 poz., Abstr. – Streszcz. pol. ref. w drukowanej części czasop., s. 42. – Tyt. numeru: KOKA 2011 : XLII. International Scientific Conference [of the Czech and Slovak Universities Departments and Institutions Dealing with the Research of Combustion Engines, Žilina, Slovakia, 8-9.09.2011]. – ISSN 1337-8996

European Union legal articles applying to the fuels used in the combustion engines must be supplement with the bio fuels. In the case of the fuels for Diesel engines, it will be rape oil methyl esters ... więcej

European Union legal articles applying to the fuels used in the combustion engines must be supplement with the bio fuels. In the case of the fuels for Diesel engines, it will be rape oil methyl esters (RME, FAME). In 2012, this additive will be 7% and in the next years, further increase of RME percentage in the fuel is expected. The addition of the bio fuels to the diesel fuel influences the combustion process and, consequently, energy parameters, exhaust gas toxicity and a Diesel engine maintenance. The research results presented in this paper are a preliminary estimation of the influence of the oil and RME (FAME) mixture on the work of the fuel injectors in a Diesel engine. The level of coking in the nozzles was determined by tests using 6 fuels in turn: standard diesel fuel (ON), mixtures containing 30, 40, 50 and 70 % of the B100 fuel with the diesel fuel (mass concentration) and the B100 fuel. The level of nozzles coking was investigated by a special test, performed on the experimental high-speed Diesel engine SB3.1 with direct injection of the fuel into the combustion chamber. The level of coking in a nozzle fuelled by diesel fuel and tested fuels was determined on a special measuring stand. In the basic tests, the level of coking in the nozzles was evaluated after performing a 13-hours test of the engine operation. The coking effect is due to the sedimentation of the thermal cracking and/or chemical products on and in the nozzles. In addition, the inside of the combustion chamber is polluted. For this reason, the examination of the injector after the coking test (engineless test stands) was done considering measures and analyses of the following parameters: - estimation of the coking degree in the nozzle outlets - estimation of the coking on the nozzle outside surface - estimation of the flow-off quality in the nozzle needle - estimation of the nozzle leaking - estimation of the injector opening static pressure - estimation of the sound during spraying the fuel on a sampler - estimation of the quality and position of fuel streams from the nozzle. Primarily, to verify the scale of pollution intensity in the nozzle outlets, measurements of the coking level in the nozzles were performed using the method based on the ISO 4010 standards. The measurement of coking consists in determining the flow capacity of the nozzle outlets. The rate of air flow, at 0.6 bar of negative pressure, was measured using a laboratory rotameter. It is the measure of the coking level in the nozzle. A reduction of the nozzle outlets flow capacity by 25 % (or more) disqualifies the fuel supplying the engine and/or the engine working conditions (exploitation, control and construction parameters). It should be emphasized that the permissible flow capacity of the nozzle is a condition sine qua non though insufficient to admit the system: fuel – engine to cooperate. All parameters specified by ISO standards must be met. The view of the nozzle terminals after the coking test is substantiated with photos. Performed tests of nozzles coking, enlarged with the estimation of the nozzle flow capacity, coking on the nozzle outside part, estimation of the flow-off in the nozzle needle, estimation of the nozzle leaking, estimation of the sound during spraying the fuel on a sampler and the estimation of the quality and position of fuel streams from the nozzle, permit to formulate principal final conclusions: Fuels type B100 and B70 must be disqualified considering their effect on the correctness of the work of an injector with a nozzle. For the fuel B50, relatively large number of carbon deposits was found on the outer part of the nozzle, but the fuel type B50 can be taken into account for exploitation reasons. Fuels type B30 and B40 in the test of the nozzle coking are, in principle, acceptable; the result of the test was positive.