Alteration of fuel properties at extreme conditions – Formation of deposits in common-rail injectors

Engine and FIE manufacturers are facing an increased number of complaints on abnormal engine functioning related to internal diesel injector deposits (IDID). Possible consequences are increased emissions, rough engine running and misfiring due to impairments in the timing of the injector or modified injection quantities as well as serious engine damage by permanently incorrect injection or sticking needles/valves. It is expected that the introduction of more complex injection strategies and highly accurate but sensitive injection components into future engine generations will exacerbate the risk of dysfunctioning. Yet, there is still uncertainty about the detailed chemical structure of the deposits and the mechanisms involved in its formation. In the literature certain additives, biofuel components or metal traces are held responsible for being the root cause of deposit formation.