Wear Properties of Car Engine Shaft in Actual Engine Environment 2015-01-0686

When evaluating the wear properties of slide bearings for car engines, it is a common practice to conduct long-term physical test using a bearing tester for screening purposes according to the revolution speed of the shaft, supply oil temperature and bearing pressure experienced in the actual use of engines. The loading waveform applied depends on the capability of the tester that is loaded, and it is often difficult to apply a loading waveform equivalent to that of actual engines. To design an engine that is more compact or lighter, it is necessary to reduce the dimensions of slide bearings and the distance between bearings. This requires loading tests on a newly designed engine by applying a loading waveform equivalent to that of actual engines to slide bearings and their vicinity before conducting a firing test.

We therefore conducted an engine firing test by attaching thin-film sensors to the slide bearing part of the engine and measured the actual load distribution. We then reproduced a loading waveform in the bearing tester to allow testing under conditions equivalent to those of actual engines.

Using this newly developed tester, we conducted basic tests on the relationship between the width and wear and between the oil temperature and wear of the slide bearing. As a result, we have found that wear decreases as the width of the slide bearing increases and wear increases as the supply oil temperature increases. Nevertheless, wear does not change linearly in this phenomenon, suggesting that the effective area under pressure and the decrease of viscosity are also relevant.