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).
Comparing performance data for 2-stroke Compression Ignition and Petrol Injection engines.
| Identifier | ExFiles\Box 133\3\ scan0208 | |
| Date | 31th May 1940 | |
| 1128 To - Rm.{William Robotham - Chief Engineer} from Wd.{Mr Wood/Mr Whitehead} Wd.{Mr Wood/Mr Whitehead}8/RS.{Sir Henry Royce's Secretary}31.5.40. 2-STROKE C.I. AND P.I. ENGINES. -------------------------------- With reference to your request in Rm.{William Robotham - Chief Engineer}3/ML.25.5.40, the only useful work done in this country to our knowledge is by Ricardo, Messrs. Armstrong-Whitworth Securities Co. and ourselves. With regard to R.R. results, we succeeded after only 20 hours running experience on our 2-stroke C.I. engine in reaching 140 b.m.e.p. at 2500 r.p.m. As you know this work was stopped in order to carry on with Petrol Injection but we see no reason why the C.I. 2-stroke should not be developed to give take-off m.e.p's of the order of 160 up to 2700 r.p.m. with consumptions of the order of .38 up to .4 lbs/BHP/hr. up to m.e.p's of 150 and Ricardo has actually got very close to these results. With regard to Petrol Injection, we have run up to 175 b.m.e.p. at 2500 r.p.m. and, as you know, have completed 50 hours endurance running at 150 b.m.e.p. 2500 r.p.m. giving an output of 60 HP/litre, and the strip of the engine after this endurance run was perfect in every respect. It should be explained to Olley that the pistons are considerably cooler than 4-stroke pistons at 75% of the output. Ricardo has operated up to 250 b.m.e.p. at 2750 r.p.m. and an output of 180 BHP. at 3000 r.p.m. on a cylinder size of 4.84" bore by 5.5" stroke. Fuel consumptions on these Petrol Injection units run from .41 for weak mixture running to .52 lbs/BHP/hr. for rich mixture running. Compression ratio 7.2:1. All b.m.e.p's quoted are 2-stroke and gross. As Armstrong-Whitworths' are carrying on commercial negotiations with General Motors Corporation it may be preferable only to state that they are getting b.m.e.p's 25% higher than Ricardo at somewhat lower piston speeds. Is it necessary to ask Olley to treat this information as very strictly confidential ? I have been very interested in Oy's reports from America on petrol injection generally and particularly P.T.O. | ||