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).
Summary of three different diesel engine cylinder head designs and their respective pros and cons.
| Identifier | ExFiles\Box 133\3\ scan0051 | |
| Date | 2nd March 1939 | |
| 1/28 c. Rm.{William Robotham - Chief Engineer} DIESEL ENGINE PROJECTS. As the result of our discussions with six engineers, we have a very fair idea of the troubles we might expect with the various types of cylinder heads, and can clearly see why each type has come about. Briefly we can summaries without talking about details. (1). For a variable speed engine a much wider range of high output is given by an engine in which a separate combustion chamber is used, and the necessary turbulence of the air charge is created during the compression stroke. The maximum cylinder pressures are low in comparison, and since we have in mind converting an engine with the minimum of alteration, then we might not be called upon to strengthen the scantlings. We know that this head responds to supercharging. (2). The merit of the Direct Injection head is fuel economy, the operator calls the tune and the manufacturer, of course, is after business. The lowspeed torque is good, the speed range is short, however, indicating that the characteristic is of a constant speed nature. In the size we contemplate no one has yet sold an engine in this country. To get the best out of D.I. undoubtedly two inlet valves would be an advantage to promote swirl and good volumetric efficiency. Our problem here is to operate three valves and find room for an injector in the confined space and maybe fit a decompressor with the minimum of tear up and expense, it looks complex. (3). The air cell engine of the LANOVA TYPE is receiving no support in Britain in spite of it being the latest development for 4 stroke engines in America, there are three large Companies selling units, namely, MACK, BUDA, and CHRYSLER-DODGE. The results are similar to the anti-chamber engine. The design of the head is such that it demands a long stroke, which does not appeal when we consider our crankshaft limitations. Attached are curves of the three types of engine, all made to a common basis. | ||