Air Conditioning System (for Manual Air Conditioning System)
HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Manual Air Conditioning System): SYSTEM DIAGRAM
Communication Table
* *1: w/ PTC Heater
SYSTEM DESCRIPTION
1. GENERAL
(a) The air conditioning system has the following controls.
2. NEURAL NETWORK CONTROL
In the previous manual air conditioning systems, the air conditioning amplifier determined the required outlet air temperature and blower air volume in accordance with the calculation formula that has been obtained based on information received from the sensors.
However, because the senses of a person are rather complex, a given temperature is sensed differently, depending on the environment in which the person is situated. For example, a given amount of solar radiation can feel comfortably warm in a cold climate, or extremely uncomfortable in a hot climate. Therefore, as a technique for effecting a higher level of control, a neural network has been adopted in the automatic air conditioning system. With this technique, the data that has been collected under varying environmental conditions is stored in the air conditioning amplifier. The air conditioning amplifier can then effect control to provide enhanced air conditioning comfort.
The neural network control consists of neurons in the input layer, intermediate layer and output layer. The input layer neurons process the input data of the outside temperature, the amount of sunlight and the room temperature based on the outputs of the switches and sensors, and output them to the intermediate layer neurons. Based on this data, the intermediate layer neurons adjust the strength of the links among the neurons. The sum of these is then calculated by the output layer neurons in the form of the required outlet temperature, solar correction, target airflow volume and outlet mode control volume. Accordingly, the air conditioning amplifier controls the servo motors and blower motor in accordance with the control volumes that have been calculated by the neural network control.
3. MODE POSITION AND DAMPER OPERATION
(a) Mode Position and Damper Operation
Functions of Main Dampers
4. AIR OUTLETS AND AIRFLOW VOLUME
(a) Air Outlets and Airflow Volume (Front Side)
The size of each circle o indicates the ratio of airflow volume.
(b) Air Outlets and Airflow Volume (Rear Side)
The size of each circle o indicates the ratio of airflow volume.
5. A/C COMPRESSOR
(a) General:
(1) The A/C compressor is a continuously variable capacity type in which its capacity can be varied in accordance with the cooling load of the air conditioning system.
(2) The compressor consists of the A/C pulley, shaft, lug plate, swash plate, piston, shoe, crank chamber, cylinder, solenoid valve and flow sensor.
(3) The A/C pulley with built-in magnetic clutch has an A/C lock sensor that detects whether the A/C compressor is locked.
(4) A solenoid valve that is provided to enable the suction pressure to be controlled as desired.
(5) The internal valve is provided to improve the A/C compressor durability under the high speed and large thermal load conditions. The internal valve is integrated into the solenoid valve.
(b) Solenoid Valve Operation:
(1) The crank chamber is connected to the suction passage. A solenoid valve is provided between the suction passage (low pressure) and the discharge passage (high pressure).
(2) The solenoid valve operates under duty cycle control in accordance with the signals from the air conditioning amplifier.
(3) When the solenoid valve closes (solenoid coil is energized), a difference in pressure is created and the pressure in the crank chamber 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 of the piston. This compresses the spring and tilts the swash plate. As a result, the piston stroke increases and the discharge capacity also increases.
(4) When the solenoid valve opens (solenoid coil is not energized), the difference in pressure disappears. Then, the pressure that is applied to the left side of the piston becomes the same as the pressure that is applied to the right side of the piston. Thus, the spring elongates and eliminates the tilt of the swash plate. As a result, there is no piston stroke, and the discharge capacity is reduced.
6. A/C LOCK SENSOR
The A/C lock sensor sends A/C pulley speed signals to the air conditioning amplifier. The air conditioning amplifier determines whether the A/C compressor is locked or not by using those signals and engine speed signals.
7. EVAPORATOR TEMPERATURE SENSOR
The evaporator temperature sensor detects the temperature of the cool air immediately through the evaporator in the form of resistance changes, and outputs it to the air conditioning amplifier.
8. BLOWER MOTOR
The blower motor has a built-in blower controller, and is controlled using duty control performed by the air conditioning amplifier.
9. BUS CONNECTOR (AIR CONDITIONING HARNESS)
(a) A BUS connector is used in the wire harness connection that connects the servo motor from the air conditioning amplifier.
(b) Each BUS connector has a built-in communication/driver IC which communicates with each servo motor connector, actuates the servo motor, and has a position detection function. This enables bus communication for the servo motor wire harness, for a more lightweight construction and a reduced number of wires.
10. SERVO MOTOR
The pulse pattern type servo motor consists of a printed circuit board and a servo motor. The printed circuit board has three contact points, and can transmit two ON-OFF signals to the air conditioning amplifier based on the difference of the pulse phases. The BUS connector can detect the damper position and movement direction with this signal.
11. QUICK HEATER ASSEMBLY (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 fins and brass plates. 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 on/off operation of the PTC heater is controlled by the air conditioning amplifier assembly in accordance with the engine coolant temperature, ambient temperature, engine speed, air mix setting and electrical load (generator power ratio).
For example, the number of operating PTC heaters varies according to engine coolant temperature as shown in the graph below.
12. 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 air conditioning amplifier.
13. AIR CONDITIONER PRESSURE SENSOR
The air conditioner pressure sensor detects the refrigerant pressure and outputs it to the air conditioning amplifier in the form of voltage changes.