THE PRESSURE-VOLUME-QUANTITY INDICATOR-CARD 230005

In the case of the internal-combustion engine, where virtually every separate portion of explosive mixture behaves differently, the usual thermodynamic interpretations of the pressure-volume indicator-card, as applied to steam engineering, have little value. In internal combustion, the pressure-volume diagram is of value only as an expression for the product of the force exerted upon the piston-top times the distance through which the piston moves.

The paper (Indiana Section) begins with the fundamental phenomena and develops from them a diagram such that each fuel-mixture particle can be properly exposed for analysis during the process of combustion. This is termed the pressure-volume-quantity card, and it is described in detail and illustrated. An extended consideration of its surfaces follows, inclusive of mathematical analysis. Work and losses are discussed, including the mathematical derivation of the so-called pseudo-hysteresis loss, the gross and the net work done; a comparison is made with the pressure-volume card; the indicated thermal efficiency relation is treated; a representation of detonation is presented; and the important points of the paper are summarized.