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).
Letter discussing experiments on induction pipe heating to improve engine performance and prevent pre-ignition.
| Identifier | ExFiles\Box 50\3\ Scan030 | |
| Date | 5th March 1921 | |
| R.P. 250A (50 T) S H. {Arthur M. Hanbury - Head Complaints} 986. 19-2-21 G. {Mr Griffiths - Chief Accountant / Mr Gnapp} 2008 X4305 OY4/G5.3.21 March 5 1921. Mr. Claude Johnson Managing Director Rolls-Royce Ltd., London, England. Attention Messrs Royce and Hives. Dear Sir, RE PETROL. X.985 X.3764 X.4305 Replying to Mr. Royce's letter of January 24th., we certainly can endorse from our short experiments here, the conclusions arrived at by Mr. Royce. (1) The cars all run very much better in wintertime if the radiator is blanketted so that the water nearly boils. This is true even with the non-heated induction pipe. The Gall-ator people who have fitted about thirty Rolls-Royce cars with their device, reckon to hold the air under the bonnet at 170°F. {Mr Friese} (77°C) This device is strongly recommended by the owners who have fitted it. (2) The heating of the induction pipe at the T by exhaust gas is a thing we have worked on, using a direct 5/8" passage from one box and two small (5/16") escape pipes, and also using an interchange between the two exhaust boxes, first with 1" pipes and then with 5/8" pipes. We found the interchange scheme gave a much greater heat than the direct passage, and met with the trouble of pre-ignition through hot gas entering the cylinders. With one such scheme we got wet petrol in cylinders 1 and 6 and bad pre-ignition in 2 and 5 at the same time. A detailed report of these experiments have been sent to Mr. Hives. A 1" heated pipe through the inlet manifold, though it is not so well calculated to deal with wet petrol coming down the walls, appears to be far freer from the danger of pre-ignition. We have never had pre-ignition with this device. Contd. | ||