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).
The testing of various induction pipes and hot spots to improve engine fuel distribution.
| Identifier | ExFiles\Box 75\2\ scan0227 | |
| Date | 26th May 1921 | |
| Contd:- -5- Hsl/LC26.5.21. --------------- So far we have not been able to discover - why the variation of these pipes. We have proved a great number of things do not make the difference but so far we have not been able to touch the spot. The pipe which we term excellent does give wonderful results without any heat whatever. We can fit that pipe on to the engine, run at 500 R.P.M. full throttle with a mixture of the worst petrol we have been able to obtain with 20% paraffin added to it, and a cold engine. The engine fires regularly and maintained even torque. The loading up effect under these extreme conditions is hardly noticeable. This is due to the fact that the distribution is so good that in picking up, the excess of petrol is sent equally into each cylinder. As a matter of fact, applying heat to this induction pipe we get very little improvement. Attached is a table which shows the comparison of pipes. The hot spot pipe made to Lec.1350 has not given very good results. The distribution with the pipe cold, i.e., with no exhaust connected to the hot spot, is worse than the average standard pipe. With the pipes connected from the exhaust to the hot spot, we get very little improvement. We found when testing this pipe that if we applied heat higher up on the cross pipe, we got considerably better results. We therefore got another pipe made up in which the hot spot instead of being on the bottom branch pipe is carried round so that it did heat a small portion of the cross pipe. With this pipe we found that the distribution when cold was poor, much worse than the standard pipe. We proved, however, that with the hot spot in that position, gave a bigger improvement than with the contd:- | ||