In order to remove the trend term

polynomial least square method is adopted during the course of signal preprocessing

and then the different combination of structuring element of mathematical morphology is utilized

which can effectively remove the zero drift of data acquisition and filter the noise of ignition impulse.The experiment data is processed by using generalized

different structuring element sequential clustered morphological filter.The results show that the method can eliminate the trend term and de-noise the cylinder pressure signal in engine successfully.