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).
Compression ignition engines observed at the Commercial Motor Transport Exhibition.
| Identifier | WestWitteringFiles\W\September1931-November1931\ Scan090 | |
| Date | 18th November 1931 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/CHP. c. to Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to Rg.{Mr Rowledge} M.{Mr Moon / Mr Moore} c. to By.{R.W. Bailey - Chief Engineer} COMMERCIAL MOTOR TRANSPORT EXHIBITION. There were approximately fourteen different makes of C.I. engines exhibited at the Commercial Motor Transport Exhibition. With one or two exception, the performance of these engines was only very moderate, only one developing over 90 lbs/sq.in. B.M.E.P. at 2000 R.P.M. The majority of the engines employed some type of pre-combustion chamber of either the pepper-box type or the "Acro" principle; only four engines functioned with direct injection (Junker's, Renault, Thornycroft, and Crossley). It is said that engines using a pre-combustion chamber have very clean exhausts, although when the comparatively heavy fuel consumption is considered one would expect the opposite. It is thought that probably the combustion efficiency is actually high, but the considerable heat loss caused by the passage of the hot gas through the "pepper box" causes the high specific fuel consumption. The engines most worthy of notice are the following :- A.E.C. RICARDO. This engine, which has been developed in conjunction with Mr. Ricardo, gives by far the best performance of all the units in the show. It is of the pre-combustion chamber type, except that the usual small holes of communication to the cylinder are replaced by one large passage. This ante-chamber takes the form of a spherical compartment 1.875" in diameter; in which are situated the injector and a heater plug. As a compression ratio of 16/1 is utilized the latter should only be required when starting under conditions of very severe cold. The passage connecting the ante-chamber to the working cylinder is about .500" dia. The piston has a plain flat top which clears the cylinder head by approximately .062" when the former is at top centre. A Bosch injection pump supplies fuel to the Bosch pintle-type injectors: the valves of the latter being set to lift at 1000 lbs/sq.in. This engine has six cylinders 4.530" bore x 5.600" stroke, and will run up to a speed of 3000 R.P.M. The power curve peaks at 2500 R.P.M. with a value of 140 BHP. (83 lbs/sq.in. BMEP) at a specific consumption of .542 lbs/BHP/Hr. The following are representative figures :- 1200 R.P.M. 112.5 lbs/sq.in. BMEP. .425 lbs/BHP/Hr. 1600 " 101.0 " .446 " 2000 " 95.5 " .467 " 2400 " 85.0 " .521 " I was unable to find what maximum cyl. pressure is Handwritten notes: Y631 RM{William Robotham - Chief Engineer}435 | ||