Abstract
•The calculation method of torsional angle is simplified by the same teeth of gears and identical type of sensors.•A novel zero point correction method is proposed to remove the installation position deviation.•Interference signal is removed by filter and the fluctuation of zero crossing point is decreased by about 69.8%.•The torsional angle increases with the increase of engine torque and speed.•The torsional angle is not noticeable under different oil temperature.
An improved method is proposed to obtain the torsional angle at both ends of the crankshaft simply and reliably. The installation position deviation is removed with a novel correction method. A digital filter is used to decrease the fluctuation of zero crossing point by 69.8%. The relative variation of torsional angle is increased from 0.818 ℃A and 0.347 ℃A to 1.075 ℃A and 0.474 ℃A respectively for the first and fifth cylinder when the torque is increased, which is attributed to the increasing combustion pressure. With the increasing engine speed, the relative variation of torsional angle increases due to the increasing inertia force. The relative variation of torsional angle is not noticeable under different oil temperature due to the comprehensive influence of combustion and friction torque. The amplitudes of most orders have similar changing trend with the relative variation of torsional angle.