What Causes Cavitation Erosion in Diesel Engine Cylinder Liners?

Cavitation erosion is a common failure in diesel engines with wet cylinder liners. It appears as honeycomb-like pits and holes on the outer surface (cooling water side) of the cylinder liner. In severe cases, it can penetrate the cylinder wall, leading to water leakage, cylinder scuffing, and even engine failure. Its formation is not caused by a single factor, but by the combined effects of mechanical vibration, fluid cavitation corrosion, and electrochemical corrosion. Below is an analysis of the core causes:

1. Root Cause: Cylinder Liner Vibration Induced by Reciprocating Piston Motion

This is the prerequisite for cavitation erosion, and almost all cavitation problems are directly related to abnormal liner vibration.

Periodic Impact from Piston Side Thrust

During engine operation, the reciprocating piston exerts periodic side thrust on the cylinder liner wall. Especially during the power stroke, the side thrust pushes the liner to deflect to one side, while the compression and exhaust strokes apply reverse forces, causing the liner to vibrate at high frequency in a reciprocating manner.

Excessive Installation Clearance of the Cylinder Liner

Excessive clearance between the wet cylinder liner and the cylinder block bore, or insufficient clamping force on the liner flange, will cause the liner to become loose during operation, greatly amplifying the vibration amplitude. This intensifies the relative motion between the outer wall and the cooling water, creating conditions for cavitation erosion.

Wear and Imbalance of the Crank-Connecting Rod Mechanism

Wear of the connecting rod bushing, piston pin, or crankshaft main bearing increases the fit clearance, which exacerbates the impact of piston movement. This leads to a simultaneous rise in the frequency and amplitude of liner vibration, directly accelerating the cavitation process.