1. Hydraulic
system, in particular for military vehicles, with at least two functional units, one of which represents a supply unit (2) and the other a
consumer unit (4), which, spatially separated from one another, are exposed to partly the same, but in particular to different ambient temperatures which, when a
temperature limit value is exceeded, lead to the
evaporation of a water-based,
flame-resistant liquid according to its
vapor pressure curve, by means of which the hydraulic
system can be operated, wherein a pretensioning device (42;52) is present which, in order to prevent the
evaporation of the liquid when the
temperature limit value is exceeded, increases the operating pressure in the hydraulic
system in accordance with the
vapor pressure curve of the liquid, characterized in that the supply unit (2) has a pressure-resistant storage container (18) which, as a prestressing device, has an air
inlet valve (52) with an opening pressure greater than 1 bar absolute, which allows the air to flow freely into the container (18) when the liquid is withdrawn in the direction of the
consumer unit (4) and, when the liquid is returned to the container (18), only allows the air to flow out into the environment at a predeterminable pressure, the pressure value of which is selected in accordance with the
vapor pressure curve, related to the
temperature limit value. ; 2. Hydraulic system according to claim 1, characterized in that in a return line (38) coming from the
consumer unit (4) the pretensioning device is connected, which comprises a pretensioned, preferably hermetically sealed
check valve