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).
Visit to Ricardo's to discuss compression ignition (diesel) engines, focusing on the characteristics of direct injection systems.
| Identifier | ExFiles\Box 133\3\ scan0054 | |
| Date | 3rd March 1939 | |
| Me: from Rm{William Robotham - Chief Engineer}/Ed.{J. L. Edwards} By: c.c. Da.{Bernard Day - Chassis Design} c.c. Da{Bernard Day - Chassis Design}/Jnr.{Charles L. Jenner} Rm{William Robotham - Chief Engineer}/Ed{J. L. Edwards}1/R.3.3.39. Compression Ignition Engines. A visit to Ricardo's was paid on Tuesday last by Da{Bernard Day - Chassis Design}/Jnr.{Charles L. Jenner} and the writer in connection with Diesel engines. We met Mr. Thornycroft and Mr. Pitchford. A considerable amount of information was obtained, and the general impression was that for a small unit the ante-chamber engine was the best proposition, and to their way of thinking the Comet III offered the best solution. The various fundamental differences were discussed, and the principal points appeared to be as follows:- (1) Combustion Chamber. Direct Injection (a) Good fuel economy, usually in the region of .370 - .380 lbs/BHP/hr. (b) Very sensitive to fuel quality, in that a poor fuel extended the delay period giving high maximum pressure and dirty exhaust. Diagrams illustrating this were shown to us, the curves having been taken on a Gardner type single cylinder unit. (c) It was difficult to make a satisfactory job for a small engine, due to the fact that if adequate cooling were provided for a central injector, insufficient room was left for ports and valves, and poor volumetric efficiency resulted. (d) Power at low speed was fairly good, but it was inclined to fall off as the speed increased. (e) Maximum pressures were high, and Diesel knock was worse than with an ante-chamber design. (f) Starting could be accomplished without heater plugs. | ||