Experimental study of 3D trajectory of journal center of crankshaft bearings in multi-cylinder internalcombustion engine

A four-cylinder four-stroke internalcombustion engine is taken as the object, the 3D trajectory (including the plane motion of the journal in the cross-section of bearing and the movement of the journal at axial direction) of the journal center of crankshaft main bearing in the internalcombustion engine is measured under a number of operating conditions. The position of the journal in bearing is obtained by the data measured using eddy current sensors and after-processed. The results show that, there is the movement of the journal of crankshaft bearing along the axial direction in internalcombustion engine, the real trajectory of journal center of crankshaft bearing is a three-dimensional spatial curve, the trajectory of the journal center of crankshaft bearing in one working cycle is not a closed curve, there is the relatively large movement of the journal of crankshaft bearing along the axial direction, and its value is greater than the radial clearance of bearing. The more the speed and load of engine, the