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).
Carburation and petrol consumption, including a graph of engine performance.
| Identifier | ExFiles\Box 147\5\ scan0081 | |
| Date | 21th November 1925 | |
| H.R. 493A (50 M) (D.D. 91. 12-6-25) J.H.D. EXPERIMENTAL REPORT. -9- Expl. No. REF Hs{Lord Ernest Hives - Chair}/Rn{Mr Robinson}/LG21.11.25 when these are fitted, instead of making a gradual stop with the throttle closed. Again, the average speed of the car almost always is increased when driving with front wheel brakes. This in itself gives an adequate reason for increased petrol cons: CARBURATION. It is not generally realised that if a carb. is set for minimum petrol consumption to give max. power, the car will still not be running under its most economical conditions. A small amount of power must be sacrificed if economy is of primary importance. A much more potent factor, however, is that the mixture can be very much over-rich without any falling off in power and performance. This is quite clearly shewn in Graph 1V. the GRAPH 1V. TYPICAL CURVES FOR AN EFFICIENT 4-STROKE PETROL ENGINE. contd :- Graph Y-axis: B.H.P. AND PERCENTAGE THERMAL EFFICY AT 1000 R.P.M. Graph X-axis: PETROL PER LB. OF DRY AIR. Graph annotations: EFFICIENCY, B.H.P., CHEMICALLY PERFECT MIXTURE, MAXIMUM POWER. | ||