Numerical study of piston group and crosshead guide system dynamics for a two‐stroke marine engine

Abstract

Abstract Two stroke slow speed diesel engines are mainly used in deep sea going vessels such as container ships, bulk carriers, and tankers. In this article, a numerical model is developed and solved to relate impact occurrence and magnitude on engine structure to rigid body tribodynamics of the crosshead guide system for a two‐stroke marine engine. To achieve this, the reciprocating piston group is coupled to the crosshead guide shoes through the crosshead guide pin. The resulting second order nonlinear differential equations are solved for displacements, velocities, and friction characteristics of the system. The rigid body motions are important in identifying occurrences and the intensities of transient impacts between contacting surfaces. These impacts influence noise and vibration characteristics of the engine. A study of the coupled system at different engine running speeds as well as varying crosshead guide system clearances is performed. It is observed that secondary displacements, velocities, and friction characteristics increase with increase in speed and clearance on the crosshead guide system. Consequently, the impact on the engine structure increase with increase in these tribodynamic characteristics of the system. This impact is transferred to the engine surface as vibration and noise responses.

Keywords

• crosshead guide system
• impact energy and occurrence
• piston group
• rigid body dynamics
• tribodynamic analysis