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).
Specifications and performance analysis of a fuel pump, including plunger details and injection pressure.
| Identifier | ExFiles\Box 179b\3\ img013 | |
| Date | 6th January 1933 guessed | |
| -2- The rate of opening of the spill port also is greater in the R.R. pump. This should result in a more rapid pressure drop at the instant of the spill port opening, and hence less tendency to dribble at the nozzle. (4) The fluid pressure exerts no side thrust on the pump plunger. Leading Particulars of Pump. Plunger Diam. 10 mm. Plunger Stroke. 10 mm. Plunger stroke from closing of suction port, 7 mm. Static cut off (Pump angle at which plunger just closes suction port) 133º A.B.D.C. on pump. Volume of oil under compression at static cut off 0.1422 c.ins or 2.324 ccs. Capacity of unloading valve 0.002445 c.ins. = 0.0401 ccs. Volume of oil in nozzle and fuel line acted upon by unloading valve = 1.2189 ccs. Plunger displacement - pump cam angle curve is a straight line between 133º a 163º. Lift per º of pump cam movement within these limits = 0.202 mm. Plunger displacement/º = 0.01584 ccs. Spill port opening period 17.8º (pump). Spill port area (fully open) 0.129 sq. cms. Suction port area 0.74 sq.cms. Nozzle :- 8 holes .010" diam. .025" long. included angle 140º. Differential ratio of injector 0.75 Injection pressure 3000 lbs/sq.in. Lift of needle valve 0.014" Most of the preliminary work was done at the maximum injection setting of the control rod, since at this position the relief port should just not open (i.e. - there is line overlap of relief passage in the pump plunger and the relief port in the barrel) and hence theoretically there should be no spill. As a guide to the excellence of the performance of the pump the theoretical discharge at maximum injection was calculated for an injection pressure of 3000 lbs/sq.in. at 1000 r.p.m. (pump), allowing for the effect of the elasticity of the fuel and the capacity of the unloading valve. The calculation is as follows :- | ||