DBPapers
DOI: 10.5593/sgem2017/52/S20.006

PERIODICAL CHANGES IN FUEL SPRAY MICROSTRUCTURE DURING INJECTION FOR TWO FUEL SUPPLY METHODS TO STANDARD FUEL INJECTORS IN DIESEL ENGINE

P. Krause
Wednesday 13 September 2017 by Libadmin2017

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7408-09-6 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 52, 41-48 pp, DOI: 10.5593/sgem2017/52/S20.006

ABSTRACT

The research goal was to make a dimensional comparison of an average droplet of a fuel spray for two fuel supply methods to a standard fuel injector in diesel engines. The Sauter mean diameter (SMD) and other derived parameters were determined in a selected spray cross-section using Spraytec STP5000 instrument. Apart from determining a mean droplet diameter, the software allows for computing numerous derived parameters. In the first case, W1F-01 fuel injector (opening pressure - 23 MPa) was supplied by a fuel pump, PRW 2M-00, with a manual drive (max. pressure 35 MPa). In the second case, the fuel was provided from the common rail of Bosch EPS 200 instrument (max. pressure – 180 MPa). In both cases, the recurring variations of the jet parameters, such as Sauter mean diameter SMD, volume concentration Cv, span or light transmission, have been noticed. They are the result of changed fuel capacity caused by opening and closing the nozzle by the injector needle. The frequency of the changes was higher for the in-line injection pump system. Periodical increases in volume concentration Cv were accompanied by a rise of the SMD. When compared to the SMD value for the entire injection cycle, these changes were significantly higher for the scenario where the fuel pump system was used. Failure to take into consideration bigger dimension of droplets than average out of the total spraying cycle during the simulation of evaporation and combustion processes may lead, in the real conditions, to incomplete combustion in the combustion chamber. Knowledge on inhomogeneity of the random spraying process allows to develop a method to determine Sauter mean diameter in a sprayed fuel, considering the changes of values beyond average values for a fuel dose atomizing period.

Keywords: Diesel engines, fuel pressure fluctuations, droplet size