Expansion Valve: Description and Operation

GF83.40-P-2190TX Expansion Valve Component Description

Component Identification:

Location
The expansion valve is located in the left rear of the engine compartment.

Task
The expansion valve injects liquid refrigerant into the evaporator. The injection quantity is dependent on the pressure and temperature of the flowing refrigerant.

Function
When the refrigerant compressor (A9) is switched on, the pressure in the evaporator drops, whereby a diaphragm in the expansion valve bends. The diaphragm movement is transferred to a tappet. The tappet pushes a valve ball out of its seating. This in turn causes the valve to open. The opened valve enables the refrigerant to be sprayed into the evaporator.

As the diaphragm movement is dependent on both the intake pressure and the temperature at the evaporator outlet, only the specific quantity of refrigerant, as required for optimum vaporization, is injected .