S 600 Sedan (140.057) V12-6.0L (120.982) (1996)
Expansion Valve: Description and Operation
The expansion valve sprays the liquid refrigerant into the evaporator.
When the A/C compressor is switched on the pressure in the evaporator decreases causing the diaphragm (1) to flex downward in an arch. The tappet (3)
follows the motion of the diaphragm and presses the valve ball (4) away from its seat against the force of the spring (5). The refrigerant is sprayed into
the evaporator through the open valve.
Since the motion of the diaphragm (1) is dependent on the intake pressure as well as the temperature at the evaporator output, only the quantity of
refrigerant which can be evaporated optimally is injected.