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).
The development of a 4-stroke C.I. engine, detailing tests on injector cooling and performance figures.
| Identifier | ExFiles\Box 179b\3\ img192 | |
| Date | 4th August 1933 | |
| He/Hd.{Mr Hayward/Mr Huddy}1/AMR.4.8.33 contd. -2- possible to permanently obtain this power. With this end in view a number of tests were conducted and it is now believed that the cause of the sudden falling off in power and reason for the B.M.E.P. of 97.6 lbs/sq.in. being temporarily obtained is understood. Development of the R.R. 4-stroke C.I. Engine. In a previous report dated Sept. 16th 1932 the experiments where-by the new C.I. engine cylinder (referred to as C.I.2 and which differed initially from the original cylinder referred to as C.I.1 in a number of particulars detailed in the above report) was modified step by step until it differed from C.I.1 only in the following respects :- (1) Shape and size of the inlet valve passages. (2) The cooling of the injector. The arrangement of injector in the cylinder head as-at this stage of development is shown in Fig.1. Owing to a machining error, the cylinder was bored out to receive the R.R. combined pump and injector which has a larger diameter nozzle and body then the standard Bosch injector, hence a bush was screwed into the cylinder to fit the Bosch nozzle and a sleeve inserted to fit the body of the valve. Reference to Fig.9 will show that the injector housing is not of uniform thickness, it being enlarged on a section at right angles to that shown in Fig.1 to form two stud bosses. Overheating of the injector was noted in the latter tests described in the above report accompanied by a sudden drop in power after a short period of running. In the last test described the sleeve had been removed and water circulated in the space thus formed around the injector body. With this external cooling the power was somewhat more steady and in a test the following figures were obtained, 86.5 lbs/sq.in. B.M.E.P., specific consumption 0.553 lbs/BHP/Hr. Now the standard performance figures of the original C.I. engine (C.I.1) prior to its replacement at 2000 R.P.M. were :- Max. power 118 BHP. Sp.{Mr Spinney}Cons. 0.590 lbs/BHP/Hr. Normal 102 " 0.455 " Max. economy 80 " 0.425 " Motoring losses (Fig.20) 30 lbs/sq.in. MAP. at 2000 R.P.M. The test conditions were :- Compression ratio 14.2 : 1 Maximum cylinder pressure 1000 lbs/sq.in. Standard Bosch fuel injection pump FZ/1B, 10 mm. plunger. Bosch injector, 8 holes, .010" dia. .025" long x 140°. Injector needle set to lift at 3000 lbs/sq.in. Normal power figure corresponds to an injection quantity of 0.235 ccs/cycle. | ||