John M. Glidewell

Break-In Liner Wear and Piston Ring Assembly Friction in a Spark-Ignited Engine

Cylinder liner wear and surface roughness were measured at the topping reversal point of a single-cylinder, air-cooled, spark-ignition (gasoline) engine during break-in. In addition, the instantaneous factional torque of the engine was determined and correlated with the wear rate and surface roughness during this period. The engine friction, liner surface roughness and wear had their highest values at the beginning of the break-in period. The wear rate dropped sharply during the first hour, after which it maintained a steady lower rate. The surface roughness and friction took longer than the wear rate to stabilize. Friction was found to change in three modes. The first mode took one hour and was characterized by a sharp drop in wear rate and a small drop in friction. The second mode was a transition to the third mode, and took about 2.5 hours. The third mode lasted about 20 hours and was characterized by a drop in both surface roughness and friction. The wear rate did not change much during this mode. Aft...

In Situ Wear Measuring Technique in Engine Cylinders

An in situ wear probe was developed to measure the rate of cylinder liner wear and its roughness at the top ring reversal point where severe wear can occur. The wear probe can be removed from the cylinder block and replaced without the need for engine disassembly. The wear probe is scanned at a laser stylus surface measuring station where its topography and wear are analyzed. The engine used is a single-cylinder, air-cooled gasoline engine. A sample of the surface properties and analysis is given. Experimental data are given for the wear rate and different roughness parameters and their variation over the first few hours of the break-in period.

Cylinder Liner Surface Analysis During SI Engine Break-In

Surface texture of an engine cylinder liner at the top-ring reversal point was observed by using Scanning Electron Microscopy (SEM) and optical microscopy. Experiments were conducted on a single-cylinder spark ignition engine over the engine break-in period. The surface texture of the cylinder liner was observed before and after the break-in test. The changes of surface texture and the wear mechanisms during the engine break-in were analyzed. The primary wear mechanisms were found to be abrasion and plastic deformation. Presented at the 57th Annual Meeting Houston, Texas May 19–23, 2002