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).
Paper discussing the influence of supercharging and compression ratio on various engine performance metrics.
| Identifier | ExFiles\Box 140\1\ scan0207 | |
| Date | 28th March 1938 guessed | |
| -3- It is the purpose of this paper to discuss the influence of supercharging and compression ratio on power output, economy, fuel octane number requirement, exhaust gas temperature, exhaust valve temperature, and heat absorbed by the cooling water, as indicated by the results obtained in the tests. Description of Equipment. The engine used in these tests was the 8 cylinder, valve-in-head, 233 cubic inch, stock engine shown in Figure 1. This view shows the carburetter box, neon spark advance indicator, cooling water standpipe, cooling water weighing tank and scales, and the quartz window through which the temperature of the exhaust valve in cylinder No.1. was measured by means of an optical pyrometer. Figure 2. shows the instrument panel of the dynamometer and part of the special test equipment used during the tests. The supercharging equipment is shown in Figure 3. The vane type compressor is hidden by the motor control panel, but the driving motors and the first receiver are shown in this view. Figure 4 is a schematic diagram of the air supply system. Air was delivered by the compressor to the first receiver at a pressure higher than the manifold pressure of the supercharged engine. The air was piped from the first receiver to a second receiver near the engine, thence to the carburetter box and the engine. The second receiver was divided into two compartments by a partition into which the round-edge air measuring orifices were screwed. By the proper adjustment of valves numbered 1,2,3 and 4 in Figure 4, any intake manifold pressure desired could be maintained up to the maximum pressure in the first air receiver, except for the pressure loss through the delivery lines. The carburetter and carburetter box with the cover removed are shown in Figure 5. This carburetter was the standard one supplied with the engine. All fuel metering passages except the main jets were plugged to facilitate the control of air-fuel ratio. The air pressure line to the carburetter flow bowl, which was part of the air-fuel ratio control system, is clearly shown in this figure. A schematic diagram of the fuel supply system used for the tests is shown in Figure 6. The fuel was fed from the dynamometer supply line to a motor-driven fuel pump. This pump lifted the fuel to a special pressure float bowl in which the fuel was maintained at a slightly higher pressure than in the carburetter. The fuel then flowed by gravity from this pressure float bowl either to the weighing tank or directly to the electrically-operated engine fuel pump, and thence to the carburetter. | ||