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).
Engine friction, rolling resistance, and factors affecting fuel consumption.
Identifier | ExFiles\Box 178\1\ img058 | |
Date | 21th November 1925 | |
- 11 - EXPERIMENTAL REPORT. EXPL. NO. REF. Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}1/LG21.11.25. at very small throttle openings some 20° extra advance can be given with beneficial results, the car could never be run under these conditions successfully at full load however. ENGINE FRICTION AND ROLLING RESISTANCE. As will have been gathered from previous remarks, engine friction is of considerable importance in low speed petrol cons. The two main items in engine friction are the pistons and type of lubricant used. Both these are fixed by consideration of wear, piston slap and bearing durability so that, except for freak re- sults, little can be done. The engine temp. has of course an effect on the oil viscosity, for this reason steam cooling may be expected to have beneficial results on cons: Tyres again will make an appreciable effect, if the car is driven purely from an economy point of view. Cord tyres may improve the cons. 10% over canvas tyres. Hard cord tyres will be about 12% better than the same tyres badly under-inflated. To imagine however, that the cons. of an owner who averages 40 m.p.h. can be improved appreciably by attention to tyres or lubricant, is quite futile. FREAK PETROL CONSUMPTIONS. We hope the foregoing remarks have indicated how freak petrol cons. are obtained. With max. economy carb. setting, advanced ignition, high rad. temp., hard tyres, thin oil in engine, axle, gearbox high geared axle, and a constant road speed of 20 m.p.h. we anticipate that the Phantom would do 25 m.p.g. even with its present compression ratio. Hs{Lord Ernest Hives - Chair}/W. A.{Mr Adams} Robotham. | ||