Analysis of internal diesel injector deposit formation by separation science and mass spectrometry.

Abstract

Modern high pressure fuel injection equipment (FIE) has been developed to comply with stricter emission regulations and control of fossil fuel consumption in the petrochemical industry. This incorporates smaller diameter injection holes to promote atomisation and operation at higher pressures and temperatures. These new systems are more susceptible to internal diesel injector deposits (IDID) formation which can deteriorate engine performance causing a range of operational problems such as injector failure and filter blocking, leading to increased fuel usage and emission issues.
The objectives of the project are to investigate the causes of IDID and develop analytical methods for possible deposit precursor species. A number of approaches where undertaken to investigate deposit formation.
The solvency of fuel was investigated to determine if the fuels ability to dissolve particulates has an effect on deposit formation. A 10 peak data reduction model was developed to allow for quick and easy qualitative analysis of data and determination of aliphatic and aromatic components present in fuel. It was seen that injector and filter deposit samples showed greater amounts of high mass aliphatic content.
A UHPSFC-MS screening method was also developed to identify steryl glucosides, the presence of SGs in biodiesel has been implicated in deposit formation as they show limited solubility. Tandem MS experiments were also explored to identify fragmentation patterns and aid in structure elucidation.
Surface analysis was investigated to analyse the metal injector surfaces to characterise components that may be present in deposits. DART-MS and SEM-EDX were both explored for this. From the SEM-EDX data, three distinct regions were seen and a vast difference in topology was observed in the non-deposited region, a transitional region and deposited region. These different approaches worked well to give an overall understanding of the deposit formation issue and the complexity of the problem.

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Identifiers

ORCID for G. John Langley: orcid.org/0000-0002-8323-7235

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