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 improvements for engine performance related to intake pipes, fuel pumps, carburetters, and starting.
| Identifier | ExFiles\Box 122\4\ scan0006 | |
| Date | 27th December 1926 | |
| OyS-E-122726 -2- December 27, 1926. I have been wondering whether - (1) A smaller intake pipe (2) A fuel pump connected with the throttle for instantaneous strength-ening of the mixture, as used by Cadillac or Stromberg carburetters, (3) A liquid damper for the air-valve as used on the Rayfield carburetter and others by means of a loose piston working in the fuel - might not overcome this feature, without causing excessive consumption, or roughness. Probably we might have done more to help ourselves in this respect by trying the effect of altering the shape of the air slots in the air valve, or the stiffness or length of the air-valve spring. But we have few facilities for such accurate testing as seems necessary, and we have been "scared" of these items, knowing the difficulty of getting them right in the first place. B. Slow running. Probably the regularity of slow running of some American cars is due to a carburetter which is over-rich at low speeds, plus an adjustable screw-stop for the throttle in the idling position, a lower-geared engine, and a relatively smaller intake pipe. Since writing my note to Hs.{Lord Ernest Hives - Chair} of November 11th, we find that by omitting the governor on the works car we get much improved dependability in slow running. C. Throttle set open. We have tried to arrange the throttle to remain open in an idling position at all times, by attempting to start the engine with the conventional choker. We find the choker useless however for such cranking speeds as are possible in zero weather. The pilot jet will start the car instantly on zero mornings. To make the choker work at all reasonably it was necessary to - (a) Block the balancing hole between float chamber and air intake, (b) Block the holes at the base of the suction chamber and substitute two slots in the small bore of the suction chamber leading to the top of the V slots for the air intake. | ||