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).
Conclusions from injection system tests and the characteristics of an ideal system.
| Identifier | ExFiles\Box 179b\3\ img092 | |
| Date | 1st February 1933 | |
| -2- Towards the end of the report a brief sketch is given of the fundamental principles underlying the working of an injection system. This is included as it assists in the interpretation of the phenomena revealed in the tests and shows the nature of the difficulties encountered in producing a satisfactory injection system to work over a wide speed range such as is required in two-stroke engines. The main conclusions arrived at are :- (1) That with 6 suction chamber holes, injection commences too early and proceeds too long. (2) That one suction hole is sufficient for practical purposes and its use gives a satisfactory delivery-characteristic and a much reduced lag and injection period. (3) That the position of this one hole is not of great importance. (4) That the addition of an air vessel on the supply pipe has no beneficial effect. (5) That the unloading delivery valve may be dispensed with. The performance without the Valve is somewhat better than with it. and (6) That at/below 400 R.P.M. the discharge tends to become discontinuous. (7) That at maximum injection at 1000 R.P.M. there is a tendency for secondary injections to occur. (8) That the pump is now practically ready for testing in the engine. INTRODUCTION. An ideal injection system would possess the following characteristics :- With a given control rod setting at all speeds (1) The injection quantity is constant. (2) The angular interval between the sealing of the suction ports and the appearance of the jet at the nozzle (termed the "pump lag") is constant. | ||