Identification of the contribution of a coherent vibration source in a gasoline direct-injection engine using a two-input single-output model

Identification of the contributions of vibration sources in a gasoline direct-injection (GDI) engine is important in order to reduce the vibration of the gasoline direct-injection engine components. A multiple-input single-output system is identified by using the coherence method. In this paper, the contributions of vibration sources in a gasoline direct-injection engine are identified by simulating a two-input single-output model. The partial and ordinary coherence functions between the two inputs and the single output are applied to identify the contributions of the two inputs to the output. In order to evaluate the proposed method, a preliminary test was performed using a laboratory test rig. The results show that the model can be used to identify the contribution of each input to the output. Furthermore, this model is applied for identification of the vibration source in a gasoline direct-injection engine.