AIR CONDITIONING SYSTEM DETAILS

Neural Network Control

1. Previously, in automatic air conditioning systems without neural network control, the air conditioning amplifier assembly 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 performing 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 assembly. The air conditioning amplifier assembly can then perform control in a way that provides enhanced air conditioning comfort.

2. 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 assembly controls the servo motors and blower motor in accordance with the control volumes that have been calculated by the neural network control.

   

Air Conditioning Control Panel

1. A push-button type air conditioning control panel is integrated with a radio receiver assembly*1 or multi-media module receiver assembly*2.

   *1: Models with 8-speaker sound system

   *2: Models with HDD navigation system or 8-speaker surround sound system

   

   Text in Illustration

   *A	Models with 8-speaker Sound System	*B	Models with HDD Navigation System or 8-speaker Surround Sound system
   *1	Radio Receiver Assembly	*2	Multi-media Module Receiver Assembly

Air Conditioning Radiator Assembly

1. The air conditioning radiator assembly consists of the evaporator, heater radiator unit sub-assembly, servo motors, evaporator temperature sensor (No. 1 cooler thermistor) and blower with fan motor sub-assembly.

2. A semi-center location air conditioning radiator assembly, in which the evaporator and heater radiator unit sub-assembly are placed in the vehicle's longitudinal direction. As a result, the air conditioning radiator assembly has been made compact and lightweight.

   

   Text in Illustration

   *1	Evaporator	*2	Heater Radiator Unit Sub-assembly
   *a	Side View	*b	Top View
   	Front	-	-

Heater Radiator Unit Sub-assembly

1. The compact, lightweight and highly efficient Straight Flow Aluminum (SFA)-II type heater radiator unit sub-assembly is used for the air conditioning system.

   

   Text in Illustration

   *1

   Tank

   -

   -

Air Conditioning Harness Assembly

1. An air conditioning harness assembly is used in the wire harness connection that connects the servo motor from the air conditioning amplifier assembly.

   

   Text in Illustration (LHD Models:)

   *A	Models without 3-zone Control	*B	Models with 3-zone Control
   *1	Bus Connector	*2	Air Conditioning Harness Assembly
   *a	To Air Conditioning Amplifier Assembly	*b	To Evaporator Temperature Sensor (No. 1 Cooler Thermistor)

   

   Text in Illustration (RHD Models:)

   *A	Models without 3-zone Control	*B	Models with 3-zone Control
   *1	Bus Connector	*2	Air Conditioning Harness Assembly
   *a	To Air Conditioning Amplifier Assembly	*b	To Evaporator Temperature Sensor (No. 1 Cooler Thermistor)

2. The air conditioning harness assembly has a built-in driver IC with a position detection function that communicates with each servo motor connector and actuates the servo motor. This enables bus communication for the servo motor wire harness with a more lightweight construction and a reduced number of wires.

   

   Text in Illustration

   *A	Models with Bus Connector	*B	Models without Bus Connector
   *1	Air Conditioning Amplifier Assembly	*2	Bus Connector
   *3	Communication Driver IC	*4	Servo Motor
   *5	Communication IC	*6	CPU
   *7	Driver IC	-	-

Solar Sensor (Automatic Light Control Sensor)

1. The solar sensor (automatic light control sensor) consists of a photo diode, 2 amplifier circuits and a frequency conversion circuit.

2. The solar sensor (automatic light control sensor) detects (in the form of changes in the current that flows through the built-in photo diode) the changes in the amount of sunlight from its left and right sides (2 directions) and outputs these sunlight strength signals to the air conditioning amplifier assembly for the automatic air conditioning control.

   

No. 1 Ion Generator Sub-assembly

1. The No. 1 ion generator sub-assembly is controlled by the air conditioning assembly and operates in accordance with the blower with fan motor sub-assembly.

2. The No. 1 ion generator sub-assembly emits "nanoe" ions that are electrically charged and encapsulated with water. The ions are discharged into the cabin through the driver side vent to provide skin-friendly clean air.*

   *: According to temperature and humidity conditions, fan speed and air outlet mode selected, the No. 1 ion generator sub-assembly may not operate at full capacity.

   

   Text in Illustration

   *1	No. 1 Ion Generator Sub-assembly	-	-
   *a	Common Negative Ion	*b	"nanoe"
   *c	H2O	*d	Electron

   CAUTION:

   Do not attempt to disassemble or repair the No. 1 ion generator sub-assembly because it contains high voltage parts.

   Note

   Do not insert anything into the driver side vent, attach anything to it, or use sprays around the driver side vent. These things may cause the No. 1 ion generator sub-assembly not to work properly.

   Tech Tips

   
   

   • When the No. 1 ion generator sub-assembly operates, a small amount of ozone is emitted and may be faintly smelled in some situations. However, this is approximately the same as the amount that already exists in nature, such as in forests, and as such has no effect on the human body.

   • A slight noise may be heard during operation.

   • This does not indicate a malfunction.

   • "nanoe" is a trademark of Panasonic Corporation.

Mode Position and Door Operation

1. Air Conditioning Unit

   

   Control Damper	Operation Position		Door Position	Operation
   Air Inlet Control Damper	FRESH		A	Allows fresh air to enter.
   	RECIRCULATION		B	Causes internal air to recirculate.
   Air Mix Control Damper	MAX COLD to MAX HOT Temperature Setting		C - D - E (C' - D' - E') T - U - V	Varies the mixture ratio of the warm air and the cool air in order to regulate the temperature continuously between hot and cold.
   Mode Control Damper		FACE	I, K, M, O, S, W	Air blows out of the front and rear center registers, and side registers.
   		BI-LEVEL	I, K, N, O, R, X	Air blows out of the front and rear center registers, side register and front and rear footwell registers ducts.
   		FOOT	H, J, L, P, Q, X	Air blows out of the front and rear footwell register duct, and side registers. In addition, air blows out slightly from the center defroster and side defrosters.
   		FOOT/DEF	G, J, L, P, Q, X	Defrosts the windshield through the center defroster, side defrosters, side registers, and rear center register, while air is also blown out from the front and rear footwell register ducts.
   		DEF	F, J, L, P, S, Y	Defrosts the windshield through the center defroster, side defroster, and side registers.

Compressor Operation

1. Variable Capacity Operation

   
   

   • A solenoid valve is connected to the suction passage, the discharge passage and the crank chamber passage.

   • The solenoid valve operates under duty cycle control in accordance with the signals from the air conditioning amplifier assembly.

     

   
   

   • 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 lug plate. As a result, the piston stroke and discharge capacity increases.

     

   
   

   • 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 lug plate. As a result, the piston stroke becomes small, decreasing the discharge capacity.

   

2. Air Conditioning Lock Sensor Operation (Models with 2GR-FE Engine)

   
   

   • The air conditioning lock sensor outputs a pulley rotation signal to the air conditioning amplifier assembly.

   • The air conditioning amplifier assembly compares this signal with the engine speed signal sent from the ECM to judge if the compressor is locked. If the compressor is locked, the magnetic clutch is turned off.

3. Air Conditioning Mass Flow Sensor Operation

   
   

   • Using a spool that changes its position according to the amount of refrigerant flow, the air conditioning mass flow sensor detects the amount of refrigerant flow.

   • The air conditioning mass flow sensor outputs a voltage by converting the change of magnetic flux that occurs due to the magnet that is installed on the spool.

   • The spool changes its position according to the pressure difference between the pressure before and after the refrigerant flow throttle.

   • If the amount of refrigerant flow is small, the pressure difference between pressure difference inlet chamber A and B is low, allowing the force of spring B to push up the spool.

   • If the amount of refrigerant flow is large, the pressure difference between pressure difference inlet chamber A and B is high. The pressure difference overwhelms the force of spring B, and the spool moves down.

   • Based on the amount of refrigerant flow detected by the air conditioning mass flow sensor, the air conditioning amplifier assembly and ECM cooperatively control the cooler compressor assembly and the engine.

   

4. Oil Separator Operation

   
   

   • A mixture of refrigerant and cooler compressor oil flows into the oil separator chamber from the discharge chamber (*a).

   • The force of the refrigerant and oil mixture flow turns the oil separator cylinder, allowing the oil and refrigerant to be centrifugally separated (*b).

   • The separated refrigerant flows to the cooler condenser assembly through the discharge port (*c).

   • The separated oil circulates and lubricates the inside of the compressor by flowing through the oil reservoir chamber, inlet chamber, cylinder and discharge chamber. In addition, the amount of oil that is discharged by the compressor is suppressed (*d).

   • The oil separator is installed in the refrigerant passage to separate cooler compressor oil from the refrigerant that is discharged. This helps to prevent the cooler compressor oil from flowing into the air conditioning system and reducing cooling effectiveness (*e).

   

5. Variable Suction Side Throttle Operation

   
   

   • Refrigerant inlet pressure is applied to the top of the variable suction side throttle and crank chamber pressure to the bottom of the variable suction side throttle.

   • The pressure difference moves the variable suction side throttle up and down, expanding and contracting the refrigerant inlet passage.

   • When the refrigerant flow is at a maximum, the refrigerant inlet pressure is greater than the crank chamber pressure. This causes the variable suction side throttle to move down, fully opening the refrigerant inlet passage and lowering the refrigerant inlet resistance.

   • When the amount of refrigerant flow is controlled, the crank chamber pressure is greater than the refrigerant inlet pressure, raising the variable inlet throttle to contract the flow passage.

   • These controls suppress noise by reducing pulsation from the refrigerant inlet.

     

6. CS Valve Operation

   
   

   • The Crank chamber to Suction passage (CS) valve, built into the solenoid valve, operates in accordance with the suction pressure. The CS valve consists of passage A and passage B.

   • If the vehicle is left parked for a long period, refrigerant may accumulate in the crank chamber due to the heat capacity difference.

   • The solenoid valve is controlled by the air conditioning amplifier assembly. While the cooler compressor assembly is operating, the solenoid valve pushes down the CS valve rod and open passage A (*a).

   • Under the above condition, only if the refrigerant accumulates in the crank chamber, the crank chamber pressure will become high. As a result, the bellows will contract because of the pressure difference with its internal pressure (vacuum), and opens passage B (*b).

   • This causes the accumulated refrigerant to be drawn in via passage A and B, clearing the accumulated refrigerant earlier and ensuring a more immediate cooling effect.