Search Results

It is well known that lubricating oil consumption (LOC) is much affected by the cylinder bore deformation occurring within internal combustion engines. There are few analytical reports, however, of this relationship within internal combustion engines in operation. This study was aimed at clarifying the relationship between cylinder bore deformation and LOC, using a conventional in-line four-cylinder gasoline engine. The rotary piston method developed by the author et al. was used to measure the cylinder bore deformation of the engine’s cylinder #3 and cylinder #4. In addition, the sulfur tracer method was applied to measure LOC of each cylinder. LOC was also measured by changing ring tension with a view to taking up for discussion how piston ring conforms to cylinder, and how such conformability affects LOC. Their measured results were such that the cylinder bore deformation was small in the low engine load area and large in the high engine load area.

This study has been conducted aiming at an experimental verification of the ring collapse phenomena that occurs in a taper faced second ring of a direct fuel injection type truck diesel engine. The oil film thickness of the second ring, the ring axial motion and the inter-ring pressure have been measured under various operating conditions of engine. As a result, it is verified that the back pressure of the second ring becomes lower than the second land pressure, and that the second ring oil film becomes extremely thick temporarily where the second ring contacts with the ring groove upper surface. It is also verified that blow-by passes through the second ring where the oil film of the second ring becomes thick. Hence it is highly probable that the collapse of the second ring has occurred at that time.