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).
Preliminary rig test results for a combined pump and injector for a four-stroke C.I. engine.
| Identifier | ExFiles\Box 179b\3\ img012 | |
| Date | 6th January 1933 | |
| To R.{Sir Henry Royce} from He/Ud. C. ag. Nor. C. RS.{Sir Henry Royce's Secretary} Ry. C. F.{Mr Friese} Fl. He/Ud.7/KT.6.1.33. X4433 R.R. COMBINED PUMP & INJECTOR. PRELIMINARY RIG TESTS. The object of these tests was to test the delivery characteristics and the mechanical construction of the pump prior to fitting to the four stroke C.I. engine. A sectional drawing of the pump and injector is shewn in Fig.1. The suction port is controlled by the lever end of the plunger passing the bottom of the annulus cut in the pump sleeve. Relief is controlled by the square relief passages in the plunger passing the helical ports in the sleeve. Rotation of the plunger about its longitudinal axis causes the relief passage to be uncovered earlier or later in the pump stroke and thus controls the quantity injected. Beneath the pump chamber is an unloading delivery valve from which a short passage leads to the injector. No external means of adjusting either the static injection pressure or the fuel valve needle lift are provided. The following features of the pump are noteworthy - (1) Small volume of oil in pump chamber and fuel line. The advantage of this is that it reduces the effects arising from the elasticity of the fuel oil such as reduction of delivery quantity with speed, increase in injection period etc. A disadvantage is that it increases the rate of rise and the magnitude of the fuel line pressure with pump speed. (2) Separate suction and spill chambers. The purpose of this was to eliminate the pressure surges in the suction pipe set up by the spill when discharging into the suction chamber. These surges tend to interfere with the proper filling of the pump chamber. (3) Large spill port area. In the R.R. pump this is 0.129 sq.ins. (2 square holes 0.1" side) and in the Bosch 0.0785 sq.ins (1 hole 0.118" dia.) | ||