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 experimental stage of a vaporiser scheme, comparing its performance with and without an exhaust heated throttle.
| Identifier | ExFiles\Box 78\1\ scan0313 | |
| Date | 1st November 1921 guessed | |
| -2- letters Hs{Lord Ernest Hives - Chair}5/LG20.9.21 and Hs{Lord Ernest Hives - Chair}4/LG23.9.21 that difficulty was met with in obtaining proper distribution with the device when made experimentally in accordance with this scheme and that at latest advices steps were being taken towards correcting this experimentally. (b) That from the above remarks it appears that the device is still in the experimental stage at Derby and is not ready for adoption on production. (c) That the use of the vaporiser scheme attached to our existing induction pipe without the exhaust heated throttle, we believe that the following good results are attainable. (1) "Loading-up" is eliminated. (2) Fouling of plugs is eliminated. (3) Formation of carbon is greatly reduced. (4) Crankcase dilution is reduced. (5) Piston knocking when starting from cold is practically eliminated with consequent reduction of wear, reduced risk of seizure, etc. (6) Decreased fuel consumption. These are the results which the exhaust heated throttle is intended to produce. Hence we think that the results aimed at can be obtained by the vaporiser scheme alone without the use of the exhaust heated throttle. (d) The exhaust heated throttle does not, however, do all the things which the vaporiser scheme will do because it does not prevent crankcase dilution when starting from cold. (e) The exhaust heated throttle is therefore an additional expense, which from present indications we believe it is not necessary to incur, from the results of our experimental and testing work to date. We have now made and tried out about 12 induction pipes with the vaporiser scheme but without the heated throttle, on 12 different cars with satisfactory results, and have therefore had sufficient experience with the device to believe that we can achieve an improvement in running in every case. The expense of the exhaust heated throttle is we believe greater than the vaporiser scheme because it involves actuating mechanism, large diameter pipe work and a new throttle casting, scrapping our existing castings, 160 of which have been final-machined. (f) From Mr. Hives' experimental results in England, we understand that the exhaust heated throttle causes an contd:- | ||