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).
General conclusions on engine self-ignition tests, comparing the Phantom and Silver Ghost models.
| Identifier | ExFiles\Box 66\2\ scan0198 | |
| Date | 18th June 1926 guessed | |
| contd :- -5- GENERAL CONCLUSIONS. The conclusions we draw from the results of our tests are that when self ignition takes place it is due to the compressed charge picking up heat from the hot exhaust valve. Low rate of revolution in conjunction with the hot valve is favourable for self ignition and seems due to :- (1) Little or no turbulence - and - (2) Longer time period for the charge to pick up heat. The phenomenon is influenced by the nature of the fuel or, probably to state it more correctly, by the self-ignition temperature of the fuel. Benzol is better than petrol in this respect. Water temperature seems to exert little influence. High air intake temperature is favourable for self ignition or rather the higher the air temperature the lower may be the temperature of the valve to give ignition. It would seem that any condition which tended to raise the temperature of the charge would aggravate the trouble. Comparing the Phantom with the Silver Ghost - which we know is not such an offender in this respect - we have no definite proof that any of the above mentioned factors account for the difference between these two engines. From observation of both on the test bed at full throttle there seems little difference between the valve temperatures but we know the Phantom engine requires more ignition advance and from that assume its turbulence is less. contd :- | ||