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).
The relationship between pressure and volume of combustion products, referencing Janeway's theory and adiabatic expansion.
| Identifier | ExFiles\Box 133\1\ scan0257 | |
| Date | 21th July 1927 | |
| -4- RELATION BETWEEN PRESSURE AND VOLUME OF COMBUSTION PRODUCTS. Janeway derived a relation between pressure and volume which is slightly in error due to the assumption of isothermal expansion of the products of combustion. It has been proved that actually this expansion is adiabatic. In the appendix, a relation similar to that of Janeway has been derived. Fig.4 shows the relationship between mass and volume burned, and since pressure developed is proportional to mass burned, a relationship between volume of combustion products and pressure at any instant is easily calculated. VOLUME-DISTRIBUTION. Now it is clear that the flame travel and the volume burned are not lineally related, as is illustrated in Fig.5., and this is shown graphically in Fig.6. (5) (6) Combustion chambers, on the other hand, are usually so shaped that instead of lying below the ideal, they go above it, as in Fig.7. This curve, however, does not take into account changes in volume due to piston movement, and for purposes of comparison this is not necessary. To calculate the pressure-time curve for the burning, however, piston movement must be allowed for. | ||