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.
Magnet Clutch [Manual Air Conditioner]
Purpose
The magnetic clutch transmits the rotation force from the engine to the shaft
in the A/C compressor.
Function
The magnetic clutch engages or disengages the magnetic clutch and the A/C
turns on or off by switching the power transmission from the engine.
Con ...
Tire Pressure Monitoring System Set Switch Inspection
1. Remove the TPMS set switch..
2. Verify that the resistance between the TPMS set switch terminals B and C is
as indicated in the table.
If not as indicated in the table, replace the TPMS set switch.
TPMS set switch specification
Terminal
...
Fuel Filler Cap Inspection
Leakage Inspection
1. Perform the following tester (evaporative emission system tester (134-01049A))
self-test:
NOTE:
If the tester does not work correctly during self-test, refer to the tester
operators manual for more detailed procedures.
a. Verify that the gas cylinder valve ...