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).
Dual ignition system with automatic advance via an oil relay.
| Identifier | ExFiles\Box 65\1\ scan0099 | |
| Date | 17th March 1925 | |
| R.R. 493A (50H) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. -3- Expl. No. REF:Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/LC17.3.25. expected to maintain this synchronisation over their full range indefinitely. This would mean that the car would be subject to detonation soon after it left the Works. In the R-R system, the two ignitions are linked together so that their movement for automatic advance is always identical. A very light governor gives the required advance characteristics and its movements are transmitted to the linkage via the oil relay. This exactly reproduces the movement of the governor but augments some 20 times the force available for moving the linkage. The layout provides positive synchronisation of both ignitions at all speeds, and also automatic advance to suit the engine requirements, the latter being unaffected by any stiffness which can normally occur in the controls due to the enormous amplification in the governor effort produced by the oil relay. Other more obvious advantages that are obtained from 2-point ignition in large cylinders are :- (a) Ability to fire weak mixtures consistently. (b) Improved slow running. ------------------ Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||