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).
Graph comparing the effect of choke size variation on BMEP for a Ramp Head versus a Standard Head in Bentley single cylinder tests.
| Identifier | ExFiles\Box 133\2\ scan0071 | |
| Date | 1st November 1937 | |
| SHEET 7 BENTLEY SINGLE CYLINDER TESTS. EFFECT OF VARIATION IN CHOKE SIZE ON BMEP NATURALLY ASPIRATED OPEN EXHAUST FUEL - N° 1 SHELL COMPRESSION RATIO: RAMP. 6·59; STD. 6·40 VALVE TIMING (.020 CLEARANCE): I.O. 4°E; I.C. 51°L; E.O. 51°E; E.C. 7°L. (STANDARD BENTLEY) Graph 1: RAMP HEAD LABELS: NO CHOKE, 32% CHOKE, 30% CHOKE, 28% CHOKE, 4500 RPM, 4000 RPM, 3500 RPM. TEXT BOX 1: VARIATION IN BMEP WITH RPM (CONSTANT CHOKE SIZE) TEXT BOX 2: VARIATION IN BMEP WITH CHOKE SIZE (CONSTANT RPM) VERTICAL TEXT: INLET VALVE PORT DIA. (1.500") Graph 2: STANDARD HEAD LABELS: NO CHOKE, 32% CHOKE, 30% CHOKE, 28% CHOKE, 4500 RPM, 4000 RPM, 3500 RPM. TEXT BOX 1: VARIATION IN BMEP WITH RPM (CONSTANT CHOKE SIZE) TEXT BOX 2: VARIATION IN BMEP WITH CHOKE SIZE (CONSTANT RPM) VERTICAL TEXT: INLET VALVE PORT DIA. (1.350") AXES LABELS & VALUES: Y-AXIS: PERCENTAGE GAIN OR LOSS IN BMEP RELATIVE TO A 32% DIA. CHOKE VALUES: 6%, 4%, 2%, 0, -2%, -4%, -6%, -8%, -10%, -12%, -14% X-AXIS (Bottom): R.P.M. VALUES: 2400, 2800, 3200, 3600, 4000, 4400 X-AXIS (Bottom Right): DIAMETER OF CHOKE VALUES: 28%, 30%, 32%, 34%, 36%, 38% STAMP (Bottom Right): WOB 11/37 | ||