Feasibility of applying controllable lubrication to the main bearings of reciprocating engines

By using a multibody dynamic model of a single cylinder combustion engine, coupled to the equations that describe the dynamics of the fluid film generated by hydrodynamic pressure in the main journal bearing, this work deals with the feasibility of reducing wear and vibrations in the system components by means of applying hybrid controllable lubrication conditions to the crankshaft journal bearing. The hydrodynamic pressure is described by the Reynolds equation, which is modified to accommodate the active lubrication conditions and numerically solved by means of the finite-difference method. The reaction journal bearing forces are obtained when the pressure distribution is integrated over the pressure area. These fluid film forces are coupled to the set of nonlinear equations that describes the dynamics of the reciprocating engine. The results are obtained for five different cases of controllable hybrid lubrication conditions of the main journal bearing. The analysis of the results is focus on the behaviour of the maximum fluid film pressure, minimum fluid film thickness and the cyclic averaged power consumption.