The definition differs in the relevant literature. Often only the reversible part is defined as technical work (see below) and the work, which also contains the dissipated energy , is referred to as "inner work".
Relationship between volume change work and technical work in the pV diagram
While the volume change work is a one-time work performed on the closed system , the technical work is transferred continuously or periodically . In addition to the volume change work, there is also the shift work at the entry and exit of the system:
The pushing work is transferred from the pressure accumulator 1 with the pressure to the piston of the compressor. Then the chamber volume is the same at bottom dead center (in the sketch on the right) .
Volume change work: by moving the piston from bottom dead center to the left, the pressure of the gas is increased and its volume is reduced when the valves are closed (point 1 to point 2 of the above diagram). The valves can be thought of as flaps that close automatically due to excess pressure on the plate side and vice versa. When moving to the left, the lower flap closes; the upper one only opens when the pressure has been reached through compression ( volume work in a closed system) .
After performing the volume change work, the compressor has to perform the pushing out work in order to push the gas into the cylinder 2 at a constant pressure . When moving to top dead center (to the left in the sketch), the piston ideally pushes the gas out completely, i.e. H. the chamber volume is then zero.
The sum of the work done is the technical work that must be done by the crankshaft . The process is repeated with the next turn of the crank.