In recent years there have been significant changes in the composition and quality of fuels. In addition to those already present, new biofuels and alternative components are entering the market. At the same time, especially with efficient diesel engines, there is a trend towards long ranges and the associated long dwell times of the fuel in the tank. In addition, high return temperatures of modern common rail injection systems promote fuel ageing in the tank. It is known that aged fuels have an increased tendency to form deposits in the injectors. Modern, highly agile injection components with extremely small gap dimensions or flow cross-sections are becoming increasingly sensitive to internal deposits.
In the DGMK project, the research units have investigated 784 deposit formation mechanisms and simulated the formation of deposits on a non-motor test bench. The observed deposit formation was specifically induced by in-situ degradation of the fuel on the test bench. By means of adapted and partly further developed evaluation routines, functional tests of injectors were carried out in order to assess the impairment of the injection process.