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).
Table and analysis of power increase from supercharging an engine with a 5.55 to 1 compression ratio.
| Identifier | ExFiles\Box 140\1\ scan0216 | |
| Date | 28th March 1938 guessed | |
| -12- TABLE III. Power Increase Resulting From Supercharging Engine With 5.55 to 1 Compression Ratio by a Separately-Driven Blower To An Intake Manifold Pressure Of 10 Inches Of Mercury Above Atmospheric Over The Speed Range. Percent of Work of Unsupercharged Engine Or Theoretical Cycle at Speed Considered Engine Speed, R.P.M. Total Boost, In. of Mercury * Actual Engine Theoretical Cycle "Normal" Scavenging "Complete" Scavenging 500 10.17 144 140 164 1000 10.5 147 142 166 1500 10.9 151 145 168 2000 11.4 154 148 172 2500 12.0 157 151 176 3000 12.6 157 155 179 3500 13.2 158 159 183 4000 13.5 155 161 185 * Above intake manifold pressure of engine when operated at full throttle unsupercharged at same speed. It will be noted that the power increases for the actual engine were greater than for the theoretical cycle with "normal" scavenging up to 3500 revolutions per minute. At this speed and above the actual engine gains were less than the theoretical values. This is believed to have resulted from the fact that the actual engine was approaching the speed of maximum power for the boost used. Volumetric Efficiency, Brake Mean Effective Pressures, Torque and Compression Pressures The correlation between volumetric efficiency, brake mean effective pressures, torque, and compression is interesting. These values are shown on figures 18, 19, 20, and 21 respectively. It will be noted that the peak of each curve appeared at approximately the same engine speed. Whether there is any significance in the fact that the peak of the compression pressures and brake | ||