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).
With a diagram proposing an automatic ignition advance mechanism, discussing its implementation and relation to preventing engine detonation.
| Identifier | Morton\M20.1\ img004 | |
| Date | 1st April 1924 guessed | |
| (3) To keep all dirt out of the central valve there will be a fine gauze filter at the entrance. The piston unit, valve, and cyl. should easily come away for cleaning. Somewhere in the circuit of controls there will be a floating lever thus:- [Diagram Annotations] Top left: from hand control .5 Middle left: .3 of the advance & .2 adjustment + & - Bottom left: .7 of the total distance obtained from this. Top right: Pin carried by crank. Middle right: To mag. & battery control. Bottom right: Travel say 1" for full advance from starting retard. Piston can be arranged to advance the control as soon as oil pressure created, say .3 of the total advance. Figures given here are parts of the total required advance, not inches. Therefore .4 would be automatic and total 1.2 - i.e. .2 more than theoretically required. The ordinary governor advance would be deleted and this fitted in the same place. A magneto of the sleeve type would be needed, having ample advance. Can you make a scheme of these items? Find places for them as soon as other work will allow. Naturally we shall have troubles such as the battery ignition wires must permit of a large angle of advance of the distributor, unless we fit a sliding sleeve advance for the battery ignition as we have done before. In some ways this would be best. This has now advanced far enough to seem possible. It is badly wanted for EAC.2. if possible, but would also require the second plug in a better position. This subject deserves attention as it bears so directly upon the detonations. In addition it is assumed that the con. rods may require lengthening, and every fraction of weight removing from the reciprocating end of the con. rod and piston. I assume that we have the lightest type of pistons which do not knock. How much lighter would Ricardo's be? Has he succeeded in preventing knocks? Home on the 10th April. R.{Sir Henry Royce} | ||