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.
Vacuum Pump Inspection
1. Pinch open the clamp using pliers and disconnect the vacuum hose from the
vacuum pump..
2. Install the vacuum gauge as shown in the figure, then check the vacuum.
3. Warn up the engine.
If the pressure is less than the specification, inspect for the following.
Malf ...
Shift Pressure Control (Direct Electric Shift Control) [Fw6 A EL, Fw6 Ax EL]
Outline
The TCM drives shift solenoids No.1, 2, 3, 4, the pressure control solenoid,
and the on/off solenoid based on inputs signals from each switch and sensor,
and performs direct electronic control of the clutch engagement pressure. As
a result, precise hydraulic pressure control ...
Engine Tune Up
Engine Tune-up Preparation
NOTE:
If the accelerator pedal is depressed continuously for a specified time,
the engine speed may decrease to the idle speed. This is due to the fuel cut
control operation, which prevents overheating, and it does not indicate a malfunction.
The engine s ...