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 an engine's automatic pressure control system, detailing the function of a reservoir, valves, and an aneroid apparatus.
| Identifier | Morton\M8\ img021 | |
| Date | 1st June 1917 | |
| To J.{Mr Johnson W.M.} from R.{Sir Henry Royce} 2. pipe. Nominally this small reservoir is closed to the atmosphere, so that the first turn or two of the engine (by hand or otherwise) would cause the pressure in it to fall considerably if it were not fitted with one or more automatic air valves, which open when the difference of pressure between the inside of this reservoir and the atmosphere is 4.5 lbs. In addition to this valve, the pressure in the reservoir is controlled by an aneroid apparatus, which makes an electrical contact when the atmospheric pressure within the reservoir falls below 10.5 lbs. to the square inch. The electrical circuit so formed by the aid of an electro magnet, actuates a small valve admitting oil to a cylinder, which in its turn actuates a valve, slowly opening the small reservoir to the atmosphere until the atmospheric pressure within the reservoir is maintained at the desired amount. This mechanism is operated by the lubricating oil pressure from the engine, and is controlled by a dashpot to make its operation at the desired rate. Nominally this relief valve is closed, and will only open if the engine is running and there is a satisfactory oil pressure, and the air pressure in the reservoir is below 10.5 lbs. to the square inch. It will be noticed that the automatic valves mentioned above are practically only used for starting the engine and running while the oil pressure gets up in the engine. As soon as this happens the aneroid barometer apparatus takes charge of the pressure admitted to the induction system of the engine. (Contd.) | ||