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).
Effects of increased compression ratios on engine performance and exhaust cooling.
| Identifier | WestWitteringFiles\B\July1918\ Scan0 | |
| Date | 5th July 1918 | |
| E H/L C To EH. from R.{Sir Henry Royce} Copy to CJ. [Stamp: ORIGINAL.] D 5th July, 1918. R1/G5718 [Stamp: RECEIVED] X.2295 X.2555 [struck through] X.2574 RE COMPRESSION RATIOS. Thank you for your memo re compression ratios. We always had the impression that an increased compression ratio lowered the terminal pressure, and would naturally suggest a cooler exhaust. We were not aware previously that it made any difference to the temperature of the exhaust valve, and your observations on this point are extremely interesting. We also had the impression that an increased com-pression enabled a weaker mixture to burn rapidly. It will also be found we think, that with an increased compression ratio, a greater proportion of the heat of the fuel passes to the water jacket and also a greater amount is turned into useful work, both of which would have a tendency to cool the exhaust quite materially. In conclusion, I think these investigations to be of the utmost importance, and thank you for the successful way in which you are conducting them. R.{Sir Henry Royce} [Stamp: RECEIVED JUN 8 1918] [Faint text at bottom: F H S32V (200 L) (2'D '08 S9+I1) BW S12EIT3] | ||