Structure analysis of the surface of plunger and barrel assembly in the injection pump pumping section

Precision surfaces in a diesel engine’s fuel system are used in the two components. First one is the pumping section in the injection pump. The second ones are injectors. In this paper authors present results of the topography measurements of the surface of plunger and barrel assembly in the injection pump pumping section. The measurements were performed using the atomic force microscopy (AFM) NT-206. The measured surface topographies were shown in the form of two and three-dimensional views of selected areas of the investigated surfaces. There are also presented the profiles of the selected area cross-sections as well as roughness height distribution and cumulative height distribution of roughness. Additionally, the basic parameters describing the surface roughness, such as: a roughness average Ra, a root mean square value Rq of roughness, a skewness Ssk (Rsk) and kurtosis Sku (Rku), are also specified. The samples (plungers and barrels), which have been measured, come from the injection pump pumping section as a new ones and after estimated period of operation time. The lateral precision surfaces have been measured. The atomic force microscope NT-206 allows to perform scanning of the measured surface with maximum are dimensions of 32 μm x 32 μm and maximal roughness height of ± 1 m. Scanned surfaces was divided into 256x256 measuring points and the measurements were performed in the static (contact) mode. After surface scanning on the atomic force microscope, the data was calculated in the SurfaceXplorer® 1.311 or Gwyddion 2.35 software. In this paper, only selected surfaces from the several dozen performed scans are shown. The obtained results allow to determinate the degree and type of wear of tested surfaces at the micro-level.