Recursive Engine In-Cylinder Pressure Estimation Merely Using Structural Vibration Signal

The cylinder pressure signal is a very useful indicator for advanced high-performance internal-combustion engines equipped in modern automobiles. In this paper, our previous framework for cylinder pressure estimation is revisited, and based on which a novel strategy for cylinder pressure estimation merely using vibration signal is proposed. The main idea behind the previous framework is to use the information of both engine structural vibration signal and crank angular speed signal to recursively estimate the cylinder pressure based on the Kalman filter. Different with the previous work, here, the engine speed is estimated using the vibration signal instead of being measured by a crank angular speed sensor, which leads to the so-called solely vibration-based cylinder pressure estimation method. The estimated crank angular speed is compared with the calculated one. Two combustion metrics, pressure peak P
_max
and peak location P
_loc
, are used for evaluating the proposed method. The cylinder pressure estimation results are compared with both experimental data collected from a four-cylinder diesel engine and previous estimation results, and illustrate the effectiveness of the proposed method.