System Description
HEATING / AIR CONDITIONING: 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
*2: Models with Cold Area Specification
3. AIR OUTLETS AND AIRFLOW VOLUME
(a) Air Outlets and Airflow Volume
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 is provided to enable the suction pressure to be controlled as desired.
(4) The plastic DL (Damper Limiter) type A/C pulley is used.
(5) The 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 applied to the right side of the piston becomes greater than that applied to the left side. This compresses the spring and tilts the lug plate. As a result, there is a large piston stroke and 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 Assembly)
(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 water 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 water 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.
9. A/C FLOW SENSOR (for 2ZR-FE)
The A/C flow sensor, which is mounted on the A/C compressor, is used to detect the amount of refrigerant flow. The A/C flow sensor converts the amount of refrigerant flow that is detected to a voltage value to send it to the A/C amplifier. The voltage value sent from the A/C flow sensor changes depending on the amount of refrigerant flow. As the amount of refrigerant flow becomes larger, the voltage becomes lower. As the amount of refrigerant flow becomes smaller, the voltage becomes higher. The A/C amplifier supplies 5 V to the A/C flow sensor and monitors change in the voltage value sent from the A/C flow sensor. The A/C amplifier then sends a signal to the ECM via CAN communication to allow the ECM to control the engine speed while the air conditioning is on.