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).
Analysis of engine detonation related to ignition timing, number of plugs, and cylinder bore size.
| Identifier | ExFiles\Box 42\4\ Scan047 | |
| Date | 22th September 1926 guessed | |
| Hs{Lord Ernest Hives - Chair}/ACL1/T. -3- Contd. petrol and a compression ratio of 4.8 to 1. no audible detonations were evident with both ignitions in operation and synchronised. If, however, only one ignition were used detonations immediately became evident and 6° to 7° more ignition advance was required to obtain the maximum torque. With asymmetrically arranged ignitions the results vary considerably on different engines, depending upon the position of the plugs in the cylinder head and the degree of turbulence. In one example we found that one plug required 4° more advance than the other to obtain the best results. When running with these ignitions synchronised the one plug exerted no influence at all and did not tend to suppress detonations in the least. (6) Influence of Cylinder Size on Detonations:- We find a large bore cylinder much more prone to detonation than a smaller bore using the same compression ratio. The detonations are also more intense with large cylinders and tend to lead to pre-ignition troubles much more readily than with smaller cylinders. The above information being of quite a general nature you are quite at liberty to make use of it, but of course we understand no reference will be made to the source. Yours faithfully, for ROLLS-ROYCE LIMITED. | ||