Air Conditioning System (for Manual Air Conditioning System)

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Manual Air Conditioning System): SYSTEM DIAGRAM














HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Manual Air Conditioning System): SYSTEM DESCRIPTION

1. GENERAL

The air conditioning system has the following controls:





2. MODE POSITION AND DAMPER OPERATION

(a) Mode Position and Damper Operation

Functions of Main Dampers:

(a) *1: w/ PTC Heater

*2: for Cold Area

3. AIR OUTLETS AND AIRFLOW VOLUME

(a) Air Outlets and Airflow Volume









(a) The size of the circle o indicates the proportion of airflow volume.

4. A/C COMPRESSOR

(a) General

(1) The A/C compressor is a continuously variable capacity type in which its capacity varies with the cooling load of the air conditioning system.

(2) The compressor consists of the shaft, lug plate, piston, shoe, crank chamber, cylinder, and solenoid control valve.

(3) The solenoid control valve adjusts the suction pressure is provided to enable to be controlled as desired.

(4) A plastic DL (Damper Limiter) type A/C pulley is used.

(5) A rotary valve uses suction to pull refrigerant gas into the cylinder.





(b) Operation

(1) The crank chamber is connected to the suction passage. A solenoid control valve is provided between the suction passage (low pressure) and the discharge passage (high pressure).

(2) The solenoid control valve duty cycle is controlled in accordance with the signals from the air conditioning amplifier.





(3) When the solenoid control valve closes (solenoid coil is energized), a difference in pressure is created and the crank chamber pressure decreases. Then, the pressure that is applied to the right side of the piston becomes greater than the pressure that is applied to the left side. This compresses the spring and tilts the lug plate. As a result, there is a large piston stroke and the discharge capacity increases.





(4) When the solenoid control valve opens (solenoid coil is not energized), the pressure is equalized. The pressure applied to the left side of the piston becomes equal to the right side. This is performed when the spring elongates and eliminates the tilt of the lug plate. As a result, there is a small piston stroke and the discharge capacity decreases.





5. PTC HEATER (w/ PTC Heater)

(a) General

(1) The PTC heater is located above the heater core in the air conditioner unit.

(2) The PTC heater consists of a PTC element, aluminum fin, and brass plate. When current is applied to the PTC element, it generates heat to warm the air that passes through the unit.





(b) PTC Heater Operating Conditions

(1) The PTC heater is turned on and off by the air conditioning amplifier in accordance with the coolant temperature, ambient temperature, engine speed, air mix setting, and electrical load (generator power ratio).

For example, the number of the operating PTC heaters varies by the coolant temperature as in the graph below.





6. AMBIENT TEMPERATURE SENSOR

The ambient temperature sensor detects the outside temperature based on changes in the resistance of its built-in thermistor and sends a signal to the A/C amplifier.

7. EVAPORATOR TEMPERATURE SENSOR

The evaporator temperature sensor detects the temperature of the cool air immediately past the evaporator in the form of resistance changes, and outputs it to the A/C amplifier.

8. A/C PRESSURE SENSOR

The A/C pressure sensor detects the refrigerant pressure and outputs it to the A/C amplifier in the form of voltage changes.