Model-based injector deposit detection

Solenoid coil injectors are widely spread in the agricultural and heavy-duty vehicle sector. These types are installed due to their higher development status, longer service life and robustness. Nevertheless, injector problems are one of the more frequent causes of malfunctions and failures in diesel combustion engines. Due to ever smaller diameters and more precise coordination of the individual components, injector deposits can have a major influence on the function of injectors. Deposits change the injected fuel mass, the emissions and the reliability of the engine. Reliability is the by far the most important customer requirement of commercial machinery. Especially internal deposits can lead to a complete failure of the engine. For example, the injector can stick in closed or even in open position and may cause engine damage. This paper presents a method for detecting internal and external deposits in the injector. The basis for the detection method is a high sampling rate of the rail pressure sensor.The results allow a qualitative statement about the injector condition. Internal and external deposits can be distinguished. If the deposits are too big, a service recommendation for injector replacement is issued.