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).
Oil relay governor ignition, explaining the phenomenon of engine detonation.
| Identifier | ExFiles\Box 65\1\ scan0097 | |
| Date | 17th March 1925 | |
| R.R. 493A (50H) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. Expl. No. REF: Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/LG17.3.25. R-R OIL RELAY GOVERNOR IGNITION. EXPLANATION OF INCEPTION AND ADVANTAGES. The phenomena of detonation is one that has recently received considerable attention from designers. The generally accepted theory at present is that detonation is due to the spontaneous combustion of unburnt charge. This is occasioned by the wave of compression which is propagated in the cylinder and drives some of the unburnt mixture before it and compresses it against the cylinder walls. The heat engendered by this compression is sufficient to raise the unburnt charge to its spontaneous ignition temperature where it detonates instead of burning normally. The presence of local hot-spots in the cylinder head, or bad position of the exhaust valve, will naturally cause an engine to have a pronounced tendency to detonate, as any unburnt charge compressed against such a point will be additionally heated by contact. Raising the compression ratio of an engine also increases its tendency to detonate. The evils occasioned by detonation are self-evident. Pre-ignition almost invariably ensues and if this is allowed to continue, loss of power with over-heating troubles and detrimental effects on the exhaust valves. For an engine of a given cylinder head design and compression ratio, it has been established that the tendency to detonate is largely proportional to the distance from the contd :- | ||