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).
Potential causes and solutions for exhaust backfiring in a Phantom engine.
| Identifier | WestWitteringFiles\O\January1926-March1926\ Scan175 | |
| Date | 30th March 1926 | |
| TO [crossed out: HS.{Lord Ernest Hives - Chair} E.{Mr Elliott - Chief Engineer}] ) FROM R.{Sir Henry Royce} BY.{R.W. Bailey - Chief Engineer} [crossed out: RG.{Mr Rowledge}]) (Le CanadelHenry Royce's French residence.) Copy to CJ. B.J. ORIGINAL R1/M30.3.26. Delivered to WW. during the Easter holiday. PHANTOM - FIRING IN THE EXHAUST. X9230 [crossed out: X9080] I gave some of my views to Mr. Robotham when he was here: they are:- (1) Overhead valve engines do not fire such small charges as the Silver Ghost type, therefore more passes into the exhaust pipes. This could be tested, and also the new head (turbulence) and two plugs should be much better in this respect. (We have also a head to test with internal pipes at present in stock.) (2) The butterfly valve may pass more gas than the old piston valve: this could be tested off the engine, also the butterfly might have a calibrated screw to adjust the leakage for experiment because it may be worse and worse with greater leakage, then further leakage make it better because the engine may then fire all the gas that passes. (3) It has occurred to me that at slow speeds the small charges are fired, but when the speed increases with the same throttle opening the firing in the cylinders becomes very irregular, and very slow filling the exhaust pipe and firing it. (4) Our carburetter may give a more explosive mixture at these light charges than say Zenith or Claudel: this could be tested. (5) If the Sales would agree to putting down the hand control to zero while running at such high speeds as to risk explosions in the exhaust pipe, then we might arrange a definite pure air leak when the foot is entirely removed from the foot accelerator. My idea is that this can be done by the combined action of the hand and foot control, but not by one only. My impression is that this feature is not of much importance unless the cutout is open. If this were so, our fresh air leak could be controlled by the foot accelerator and the cutout control. Anyway, it is a very difficult problem to cater for, and not spoil something else, such as low speed top gear running. The same applies to many other features and problems. R.{Sir Henry Royce} | ||