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 effects of a 'hot-spot' heating system on engine performance, economy, and detonation.
| Identifier | WestWitteringFiles\O\2April1926-June1926\ Scan257 | |
| Date | 26th June 1926 guessed | |
| contd :- -6- inside the others shewing poor economy and low power, being further proof that it is not such an efficient heating system as a 'hot-spot'. The chief information derived from this test is that although high air temperature with the standard hot spot reduces the maximum power, the economy remains just as good, or slightly better compared with a normal air temperature of about 32°C. No appreciable increase in the heat flow to the cooling water could be detected when operating with a high air tempera- ture and standard hot spot temperature, neither did the tendency to detonate seem more prevalent. Normally with this compression ratio - 4.1 to 1 - when running at a steady speed of 750 r.p.m., the speed of these tests, we do not experience audible detonation therefore any increase in the tendency would not be appreciated under these conditions. We shall however when again using a high compression ratio, which gives detonation under these conditions, take the opportunity to settle this point. SUMMARY. We find that heating the ingoing air is not such an efficient method as heating the induction bend for correcting distribution errors. The heat supplied to the air for these tests was by means of an electrical heater and it is doubtful if sufficient heat could be picked up from the exhaust system of the engine at low speeds. It seems that the rate of warming up from cold would be slow unless some form of electrical heater were employed. contd :- | ||