Technical Papers
Experimental Estimation for Behavior of Cylinder Oil on Cylinder Liner Surface*
by Kazuhiko Maekawa**, Yukio Akizuki**, Susumu Matsumoto** Osamu Motomura***, Kazunori Ichimaru****
In cross head type marine diesel engines, cylinder oil is supplied at regular intervals and constant quantity from oil-feed holes to lubricate the running surface of piston rings and cylinder liner. Accordingly, it is important to determine position of oil-feed holes, timing of oil-feed, running surface profile of piston rings and cylimder liner and so on to make cylinder oil spread wider and form thicker oil film. In this study, the authors examined how the factors influence the extension of cylinder oil using the tester which simulated cross head type marine diesel engines for the purpose of utilizing small quantities of cylinder oil effectively. We found that wave-cut surface of cylinder liner has better spread-ability of cylinder oil than honed surface and wave-cut surface with oil groove has the effect of circumferential spreadability especially.
1. Introduction
The lubrication condition of the piston ring and the cylinder liner (hereinafter, referred to as "ring and liner" of the cross head type marine diesel engines has been severer and severer as the output of the diesel engines becomes larger and larger in recent years. The cylinder oil of the specified quantity is fed at the preset timing from oil-feed holes provided in the liner in order to lubricate the running surface of the ring and the liner; however, seizure and abnormal abrasion of the running surface must be prevented with a small quantity of cylinder oil since the cylinder oil is expensive, and thus, it is important to spread the cylinder oil in an extensive range of the running surface of the liner, and to determine the position of oil-feed holes to form a thick oil film, oil-feed timing and the shape of the running surface of the ring and the liner.
Many studies have been made on the theoretical analyses1)-7) and the measurements8)-11) regarding the oil film to be formed betWeen the ring and the liner, but few studies have been made on the wave-cut and the position of the oil-feed holes of the running surface of the liner specific to the cross head type marine diesel engines12)-14).
In this study, the influence of various parameters on the extension of the cylinder oil using the tester which simulated the cross head type marine diesel engines for the purpose of utilizing small quantities cylinder oil effectively, and the result is reported below.
2. Test apparatus and test method
Fig.1 shows the schematic representation of the ring and liner tester used in the experiment, and Table 1 shows the particulars thereof. The ring and liner tester simulates the cross head type marine diesel engines to basically verify the lubrication condition of the ring and liner in a condition free from in-cylinder combustion, and driven by a 185kW motor. In order to observe the spreading condition of the cylinder oil fed from the oil-feed holes with the limer of bore x stroke = Ф 120mm x 300mm, the test was carried out with the cylinder cover removed as shown in Fig.2, and the spreading condition was image-picked up and video-recorded by the CCD camera. The test was started from the condition completely free from the cylinder oil on the liner running surface, the ring and the piston to evaluate how the cylinder oil is spread over the liner running surface.
Table 2 shows the list of the test conditions. Various test parameters are set as follows.
2.1 Shape of liner running surface
As illustrated in Fig. 3, in the cross head type marine diesel engines, the liner running surface shape 1] is defined as the wave cut of the reference shape which is machined for the purpose of the oil retaining effect of the liner running surface and the spread of the cylinder oil in the circumferential direction, the liner running surface shape 2] is defined as the wave cut in which the oil-feed holes are connected to wave-like oil groove as shown in Fig.4, and the liner running surface shape 3] is defined as the honed running surface.
* Translated form Journal of MESJ vol.35, No.4 (Manuscript Received July 5, 1999)
** Mitubishi Heavy Industries, Ltd. (Fukahori-machi, Nagasaki city)
*** Mitsubishi Heavy Industries, Ltd. (Hyogo-ku kobe city)
**** Kyushu University (Higashi-ku Fukuoka city)
