Purpose
The expansion valve atomizes liquid refrigerant to facilitate cooling of the evaporator.
Function
The expansion valve reduces the pressure of liquid refrigerant rapidly to facilitate vaporization of the atomized refrigerant at the evaporator, and adjusts the refrigerant amount sent into the evaporator.
Construction
The expansion valve consists of the following parts:
Diaphragm
Temperature sensor
Shaft
Expansion valve body
Ball valve
Spring

Operation
Adjustment of the refrigerant amount supplied to the evaporator is performed by the ball valve opening angle in the expansion valve.
The opening angle adjustment is performed according to the balance of the following forces:

Refrigerant pressure (Pd) in diaphragm
Refrigerant gas pressure (PI) of evaporator under diaphragm
Spring force (Fs) pushing up ball valve
If the refrigerant gas temperature from the evaporator increases, the expansion valve increases the amount of refrigerant according to the following operations:

The temperature of the temperature sensor tightly sealed against the diaphragm increases.
The refrigerant in the diaphragm warms and the Pd increases.
If this Pd increases more than PI + Fs, the diaphragm is pressed down.
The shaft installed to the temperature sensor end presses down the ball valve.
The amount of refrigerant is increased.
If the refrigerant gas temperature from the evaporator decreases, the expansion valve decreases the amount of refrigerant flow according to the following operation:

The temperature of the temperature sensor tightly sealed against the diaphragm decreases.
The refrigerant temperature in the diaphragm decreases and the Pd decreases.
The Pd decreases less than PI + Fs.
The ball valve installed to the temperature sensor end is pressed up.
The amount of refrigerant is decreased.
Fail-safe
Function not equipped.
Evaporator Inspection
Expansion Valve Removal/InstallationOperational Range
The system operates only when the driver is in the vehicle or within operational
range while the key is being carried.
NOTE
When the battery power is low, or in places where there are high-intensity
radio waves or noise, the operational range may become narrower or the system may
not operate ...
Air Intake Control [Full Auto Air Conditioner]
Purpose
The air intake control switches the air intake port (FRESH/REC) according
to the vehicle environment.
Function
The air intake control drives the air intake actuator and switches the air
intake door position according to the operations of the REC, FRESH and defroster ...
Hazardous Driving
WARNING
Be extremely careful if it is necessary to downshift on slippery surfaces: Downshifting
into lower gear while driving on slippery surfaces is dangerous. The sudden change
in tire speed could cause the tires to skid.
This could lead to loss of vehicle control and an accident.
When driv ...