COMPARISON OF JOURNAL ORBITS UNDER HYDRODYNAMIC LUBRICATION REGIME FOR TRADITIONAL AND NEWTON-EULER LOADS IN COMBUSTION ENGINES

Abstract

WHEN A FORCE IS APPLIED ON A HYDRODYNAMIC JOURNAL BEARING OF COMBUSTION ENGINES UNDER OPERATING CONDITIONS, THE JOURNAL AXIS MOVES WITH RELATION TO THE BEARING CENTER. THIS DISPLACEMENT CAN BE DETERMINED BY THE ECCENTRICITY FACTOR E AND THE ATTITUDE ANGLE ALPHA. INITIALLY, IT IS NECESSARY TO CALCULATE THE DYNAMIC FORCES THAT ACT ON THE BEARING DURING ACTUAL OPERATION. BASED ON THE FORCE AND THE BEARING CHARACTERISTICS, IT IS THEN POSSIBLE TO DESIGN AND IMPLEMENT A MATHEMATICAL ALGORITHM THAT CALCULATES THE JOURNAL ORBIT AS A FUNCTION OF THE CRANK ANGLE. THE ALGORITHM IS BASED ON THE SOLUTION OF AN ALGEBRAIC SYSTEM OF FORCE EQUILIBRIUM UNDER TRANSIENT STATE. THE HYDRODYNAMIC FORCE AT EACH TIME STEP IS OBTAINED BY THE SOLUTION OF THE REYNOLDS EQUATION VIA THE FINITE ELEMENT METHOD. THIS PAPER ANALYZES THE JOURNAL ORBIT OF COMBUSTION ENGINE BEARINGS USING THE NEWTON-EULER AND THE TRADITIONAL PSEUDO-DYNAMICS APPROACHES FOR THE LOAD CALCULATION.