Centralised Diagnostics of Electronic and Electric Equipment in Vehicles, Engine Lighting Equipment Testing

This paper proposes a diagnostic method that deals with obtaining diagnostic information on parts of engine systems. The focus of the research is on momentary state of engine lighting equipment "all ok" and "candle fault". The final diagnostic system should recognize "cable fault" and "transformer fault" in addition. Today\´s diagnostic systems used in vehicles are based on separate diagnostic subsystems for each electronic or electric device. The basic idea of the project is to develop a centralized diagnostic method to cover all functional systems. The proposed method would expedite the overall testing time and bring other significant advantages such as savings on test equipment. The fundamental idea is that both electronic and electric devices in a vehicle have a relationship to communication control busses. Also each device can be described as an electrical consumer with its typical power consumption characteristics. Hence, the proposed diagnostic method is based on investigating transient profile on power lines of a tested device whilst changing its state from off to on. The short time Fourier transform (STFT) processing is then applied to analyze the gained signal. The analysis results evaluate the condition of the engine lighting equipment.