Matlab/Simulink based crankshaft and camshaft signal simulation model for SI engine

Nowadays, quite a number of four-cylinder SI engines are driven by an Electronic Control Unit (ECU), in this sequence control system, the event of fuel-injection, spark-ignition, process of synchronization, etc. are activated depending on the crankshaft and camshaft position signals. Thus, for a Hardware-In-Loop (HIL) development platform, a crucial point being to simulate and calibrate the crankshaft speed signal and camshaft phase signal at different engine speeds. This paper presents a model of crankshaft and camshaft signals using Matlab/Simulink/Stateflow for a 4-cylinder, 4-stroke, natural-gas/gasoline dual-fuel engine. Regular sinusoidal and arcsine waves are employed separately according to different teeth number to fit the crankshaft signal curve during a crankshaft cycle, the camshaft signal is fitted as a square signal in this work. The signal and its synchronization characteristics are obtained through calibration experiments. This model is then verified by the comparison test bench experiment under different engine speeds. The experimental result shows the high precision and fast response of the developed model.