Abstract
Keywords: Compression Ratio, Pressure Ratio, Volumetric Ratio, Effective ratio
Today, in spite of its drawbacks, the internal combustion engine is still the most convenient choice. There are still some technologies that are regarded as possible ways for internal combustion engine development, such as variable compression ratio, variable valve timing and higher expansion (Atkinson Miller cycle).
In order to fully understand these techniques, first of all, the notion of “compression ratio” should be clearly defined. Regarding its definition, in the existing literature, a certain degree of nonuniformity exists. This paper outlines the need for standardization in order to avoid any confusion that might be created by a misleading use of this term.
Therefore, the following terms are clearly defined in this paper: compression ratio, volumetric compression ratio, effective (volumetric) compression ratio and real compression ratio. Some experimental results are equally presented in order to sustain these definitions.