From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Description of the engine's oil pressure control system and the function of a spring-controlled release valve.
| Identifier | ExFiles\Box 178\1\ img137 | |
| Date | 19th May 1926 | |
| - 3 - If no means were employed to control the pressure and the path for leakage round the bearings remained constant, the discharge would increase in proportion to the engine speed, but the pressure being proportional to the square of the discharge would reach exceedingly high values. By providing a spring controlled valve which releases oil above a certain pressure - usually about 25 lbs/sq. " - it is possible to maintain a fairly constant pressure over the whole speed range of the engine. This explains the chief reason for providing a pump which supplies more oil than the needs of the bearings in order that the release valve may be in operation at all times and so provide a constant pressure. If, however, the bearings have excessive clearance, either through fitting or wear, it is possible at low speeds that the discharge through them for a certain low pressure, will be equal to the pump supply at that pressure, with consequently no oil passing through the relief valve and resulting in a drop in the normal pressure. contd. | ||