Diesel engines are widely used due to their high reliability, high thermal efficiency, fuel availability, and low consumption. They are used to generate power, e.g., in passenger cars, ships, power plants, marine offshore platforms, and mining and construction machines. The engine is at heart of these applications, so keeping it in good working condition is vital. Recent technical and computational advances and environmental legislation have stimulated the development of more efficient and robust techniques for the diagnostics of diesel engines. The emphasis is on the diagnostics of faults under development and the causes of engine failure or reduced efficiency. Diesel engine fuel injection plays an important role in the development of the combustion in the engine cylinder. Arguably, the most influential component of the diesel engine is the fuel injection equipment; even minor faults can cause a major loss of efficiency of the combustion and an increase in engine emissions and noise. With increased sophistication (e.g., higher injection pressures) being required to meet continuously improving noise, exhaust smoke, and gaseous emission regulations, fuel injection equipment is becoming even more susceptible to failure. The injection systems have been shown to be the largest contributing factor in diesel engine failures. Extracting the health information of components in the fuel injection system is a very demanding task. Besides the very time-consuming nature of experimental investigations, direct measurements are also limited to selected observation points. Diesel engine faults normally do not occur in a short timeframe. The modeling of typical engine faults, particularly combustion related faults, in a controlled manner is thus vital for the development of diesel engine diagnostics and fault detection. Simulation models based on physical grounds can enlarge the number of studied variables and also obtain a better understanding of localized phenomena that affect the overall behavior of the system. This paper presents a survey of the analysis, modeling, and diagnostics of diesel fuel injection systems. Typical diesel fuel injection systems and their common faults are presented. The most relevant state of the art research articles on analysis and modeling of fluid injection systems as well as diagnostics techniques and measured signals describing the behavior of the system are reviewed and the results and findings are discussed. The increasing demand and effect of legislation related to diagnostics, especially on-board diagnostics (OBD), are discussed with reference to the future progress of this field.
Diagnosing the technical condition of modern diesel injectors using thermal infrared cameras
