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).
Impressions and objections to a paper on automatic spark advancement.
| Identifier | WestWitteringFiles\K\August1923\ Scan20 | |
| Date | 21th August 1923 | |
| TO OX. FROM R.{Sir Henry Royce} c. to CJ. BJ. c. to HS.{Lord Ernest Hives - Chair} RP. c. to PN.{Mr Northey} BY.{R.W. Bailey - Chief Engineer} c. to H.{Arthur M. Hanbury - Head Complaints} ORIGINAL X.30149 .928 x 699 AUTOMATIC SPARK ADVANCEMENT. I was very interested in Prof: Upton's paper on automatic spark advancement. Previous to reading this paper we have long had the following impressions:- (1) As an automatic advance depending on speed can-not do everything we have always given a large range for the hand advance. (2) That the rate of burning depended upon the com-pression and also upon the richness of the mixture, being most rapid with perfect mixture and slower with either weak or strong mixture within the range of burning. Our practice has been that when the mixture is weakened we advance the hand control. We do not think it is practically possible to make this feature automatic. Personally I never thought or previously heard of the suggestion of using the induction pipe depression as a means of controlling the ignition, and certainly this seems worth testing, though I doubt whether it would justify the complication involved. There is one serious objection to making the induction pipe depression advance the ignition, and that is that the engine will not run nicely slowly, because my experiments have shewn that for slow running the ignition should neither be advanced or retarded and should occur on the top dead centre when the compression pressure is at it's highest, otherwise there are risks of the spark fail-ing to ignite the still more attenuated mixture. Thank you very much for sending the Professor's paper, and the matter will have attention by HS.{Lord Ernest Hives - Chair} to see whether we can get any good from the idea. R.{Sir Henry Royce} | ||