Diagnosing the technical condition of modern diesel injectors using thermal infrared cameras

Abstract

Fuel injectors are the most damage-sensitive component of the diesel fuel injection system in self-ignition engines. Therefore, an important issue is their diagnosis for the proper assessment of their wear condition. The paper presents a method involving the use of an image from a thermal imaging camera to assess the technical condition of injectors used in common rail injection systems. Four injectors, whose technical condition was known, were tested. Three of them were characterized by a common fault they had damaged control valve seats, while one of the injectors was fully functional. In order to precisely assess their technical condition, the injectors were tested on a test bench. While the injectors were working, the temperature of the body in the place of the control valve was measured at a constant time interval. The conducted research has shown that there is a relationship between the rate of temperature rise of the damaged injectors’ body and their maximum temperatures, and the injection dose expenditure and the overflow expenditure.