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).
Proposal for a manual detonation control lever to supplement the fully automatic ignition system.
| Identifier | ExFiles\Box 163\7\ img270 | |
| Date | 29th January 1935 | |
| [Handwritten text at top] x6013 Rm{William Robotham - Chief Engineer} I believe Buick do this HS{Lord Ernest Hives - Chair} [Printed and typed text] Copy to Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} E/TSN.1/MN.29.1.35. FULLY AUTOMATIC IGNITION CONTROL. With the above scheme there is nothing to cover the following variables, which can materially alter the tendency to detonation on cars: 1. Degree of carboning up of cylinder heads. 2. Type of fuel used. 3. Atmospheric temperature, which varies with climate, time of the year, and even time of day. I suggest that a hand lever should be provided on the engine by which an owner can shift the whole automatic timing to and fro to compensate for some of the above variables, with the option of having the control on the dashboard if he wishes. This might be welcomed by owners of the more enthusiastic type. [The following paragraph is crossed out with a diagonal line] If the cars are going to be sent out with the ignition timed just off the detonating point for maximum performance, then after a few thousand miles the automatic control will keep it just detonating the whole time, and the owner will think he has to have his car decarbonised long before this is really necessary. By intelligent use of the ignition control it is possible to double the periods between decoking a car. There is no fall off in performance for a long time after detonation has set in. Also, for owners who may wish to use better fuels like Discol or some benzol there is no gain in performance unless the ignition timing be advanced, when there is a distinct gain. The control could be called a detonation control and not an ignition control, to prevent them perpetually adjusting it while driving. In America they call it an octane lever. E/TSN. | ||