Over the last few years, problems caused by internal injector deposits have appeared sporadically in Spain. These deposits can lead to engine vibrations, unstable idling or poor starting.
This paper presents and discusses the results of a study on the internal deposits of common rail injectors from light and heavy-duty vehicles from the field in Spain since 2005. Using analytical techniques like SEM-EDS, FTIR and GC-MS, the internal deposits were analyzed and found to be composed mainly of carboxylic salts from C12 succinic acids and C16 and C18 fatty acids. Several fuel additives were analyzed using the procedure developed in this work and evidence was obtained to the effect that the chemical composition of corrosion inhibitor additive, which have been used in Spanish pipelines during the last few years, relates to the formation of the internal deposits found in the common rail injectors studied, when sodium ions are present in the fuel.
A common rail diesel engine test was developed to reproduce the internal diesel injector deposits found in the field and to verify the analytical results obtained in this work.