AIR CONDITIONING SYSTEM SYSTEM DESCRIPTION


  1. GENERAL


    1. The air conditioning system has the following controls.

      Control Outline
      Neural Network Control This control is capable of performing complex control by artificially simulating the information processing method of the nervous system of living organisms in order to establish a complex input/output relationship similar to that of a human brain.
      Outlet Air Temperature Control Based on the temperature set by the temperature control dial, neural network control calculates outlet air temperature based on input signals from various sensors.
      Dual Control*1 The temperature settings for the driver and front passenger are controlled independently in order to provide separate vehicle interior temperatures for the right and left sides of the vehicle. Thus, air conditioning that accommodates the occupants' preferences has been realized.
      3 Zone Control*2 The temperature setting for the driver, front passenger and rear passenger is controlled independently in order to provide a 3 Zone vehicle interior temperature for the driver, front passenger and rear seat. Thus, air conditioning control that accommodates occupants preferences has been realized.
      Blower Control Controls the blower motor with fan sub-assembly in accordance with the airflow volume that has been calculated by neural network control based on the input signals from various sensors.
      Air Outlet Control Automatically switches the air outlets in accordance with the outlet mode that has been calculated by neural network control.
      In accordance with the engine coolant temperature, ambient air temperature, amount of sunlight, required blower, outlet temperature and vehicle speed conditions, this control automatically switches the blower outlet to foot and defroster mode to prevent the windows from becoming fogged up when the ambient air temperature is low.
      Air Inlet Control Automatically controls the air inlet control damper to help achieve the calculated outlet air temperature that is required.
      Drives the air inlet control servo motor according to the operation of the air inlet control switch and moves the dampers to the fresh or recirculation position.
      Compressor Control Through the calculation of the target evaporator temperature based on various sensor signals, the air conditioning amplifier optimally controls discharge capacity by regulating the opening extent of the compressor solenoid valve.
      The air conditioning amplifier compares the pulley speed signals (transmitted by the lock sensor located on the compressor) with the engine speed signal (which are transmitted by the ECM (crankshaft position sensor)). When the air conditioning amplifier determines that the pulley is locked, it turns off the magnetic clutch.*3
      Defroster Control Defroster control logic is used to improve defroster performance.
      PTC Heater Control*4

      When the engine is running and the blower motor with fan sub-assembly is on, the air conditioning amplifier assembly turns on the quick heater assembly if the following conditions are met:


      • The engine coolant temperature is below a specified temperature.

      • The outside temperature is below a specified temperature.

      • The tentative air mix damper opening angle is above the specified value (MAX HOT).
      Rear Defogger Control

      When the ignition switch is ON and the rear defogger switch is pushed, the system is activated to keep the defogger heater on for approx. 15 minutes. However, the operating time of the rear defogger can be extended up to approx. 45 minutes when both of the following requirements are met:


      • Ambient Temperature: -3°C (27°F) or below

      • Vehicle Speed: 45 km/h (28 mph) or more
      Diagnosis A Diagnostic Trouble Code (DTC) is stored in memory when the air conditioning amplifier detects a problem with the air conditioning system.

      • *1: for Dual Type

      • *2: for 3 Zone Type

      • *3: for 2GR-FE

      • *4: w/ PTC Heater

  2. NEURAL NETWORK CONTROL


    • In the previous automatic air conditioning systems, 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 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 assembly. The air conditioning amplifier assembly 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 assembly controls the servo motors and blower motor in accordance with the control volumes that have been calculated by the neural network control.

    B000IE4E01

  3. MODE POSITION AND DAMPER OPERATION


    1. Mode Position and Damper Operation

      B000MMCE01
      Functions of Main Dampers
      Control Damper Operation Position Damper 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.
      Air Outlet Control Damper

      DEF

      B000M3P       		F, J, L, P, S, Y Defrosts the windshield through the center defroster, side defrosters and side registers.

      FOOT / DEF

      B000IA9       		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.

      FOOT

      B000LHU       		H, J, L, P, Q, X Air blows out of the front and rear footwell register ducts, and side registers. In addition, air blows out slightly from the center defroster and side defrosters.

      BI-LEVEL

      B000MTV       		I, K, N, O, R, X Air blows out of the front and rear center registers, side registers and front and rear footwell registers ducts.

      FACE

      B000LCZ       		I, K, M, O, S, W Air blows out of the front and rear center registers, and side registers.

  4. AIR OUTLETS AND AIRFLOW VOLUME


    1. Air Outlets and Airflow Volume

      B000H4TE01
      MODE Selection Register Footwell Defroster
      Automatic Manual CTR SIDE RR FR RR CTR SIDE
      A B C D E F G
      FACE-U*1 B000LCZ B000IQI B000IQI B000H2J B000H2J B000H2J B000K3N B000K3N B000K3N B000K3N
      B/L-U*2 B000MTV B000IQI B000IQI B000HI7 B000HI7 B000HI7 B000N5R B000N5R B000K3N B000K3N
      FOOT-F*3 B000LHU B000IQI B000K3N B000K3N B000N5R B000N5R B000HI7 B000N5R B000JQZ B000JQZ
      FOOT-R*4 B000IQI B000IQI B000K3N B000N5R B000N5R B000HI7 B000HI7 B000JQZ B000JQZ
      FOOT-D*5 B000IQI B000K3N B000K3N B000N5R B000N5R B000N5R B000N5R B000N5R B000N5R
      F/D B000IA9 B000IQI B000IQI B000K3N B000N5R B000N5R B000HI7 B000HI7 B000HI7 B000HI7
      DEF B000M3P B000IQI B000IQI B000K3N B000N5R B000K3N B000K3N B000K3N B000MHX B000MHX

      • *1: Air blows out of registers only

      • *2: Regular bi-level mode

      • *3: Regular foot mode

      • *4: Foot mode with large airflow volume from the rear footwell air outlets.

      • *5: Foot mode with large airflow volume from defrosters

      • The size of each circle ○ indicates the ratio of airflow volume.

  5. COMPRESSOR


    1. General:


      1. The 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 a pulley, shaft, lug plate, swash plate, piston, shoe, crank chamber, cylinder, solenoid valve with built-in Crank chamber to Suction passage (CS) valve, A/C flow sensor, oil separator and variable suction side throttle.

      3. The A/C pulley with built-in magnetic clutch has an A/C lock sensor that detects whether the compressor is locked.*

      4. A solenoid valve is provided to enable the suction pressure to be controlled as desired.

      5. The Crank chamber to Suction passage (CS) valve, built into the solenoid valve, operates in accordance with the suction pressure.

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


        • *: for 2GR-FE

    2. 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 air conditioning amplifier assembly.

      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.

    3. CS Valve Operation:


      1. 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.

      2. The solenoid control valve is controlled by the air conditioning amplifier assembly. While the compressor is operating, the solenoid control valve pushes down the CS valve rod and open passage A.

      3. 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.

      4. 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.

  6. A/C FLOW SENSOR

    The A/C flow sensor, which is mounted on the 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 air conditioning amplifier assembly. 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 air conditioning amplifier assembly supplies 5 V to the A/C flow sensor and monitors changes in the voltage value sent from the A/C flow sensor. The air conditioning amplifier assembly 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.

  7. A/C LOCK SENSOR (for 2GR-FE)

    The A/C lock sensor sends A/C pulley speed signals to the air conditioning amplifier assembly. The air conditioning amplifier assembly determines whether the A/C compressor is locked or not by using those signals and engine speed signals.

  8. ION GENERATOR (w/ Ion Generator Sub-assembly)


    1. The ion generator is controlled by the air conditioning assembly and operates in accordance with the blower motor with fan sub-assembly.

    2. The 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.*

      CAUTION:


      • Do not attempt to disassemble or repair the 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 ion generator sub-assembly not to work properly.

      Tech Tips


      • *: According to temperature and humidity conditions, fan speed and air outlet mode selected, the ion generator sub-assembly may not operate at full capacity.

      • When the 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.

    B000LHSE01
    Text in Illustration
    *1 Ion Generator Sub-assembly - -
    *a Common Negative Ion *b "nanoe" Ion
    *c

    H2O

    		 *d Electron

    Tech Tips

    "nanoe" is a trademark of Panasonic Electric Works Co., Ltd.

  9. EVAPORATOR TEMPERATURE SENSOR (NO. 1 COOLER THERMISTOR)

    The evaporator temperature sensor (No. 1 cooler thermistor) 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 assembly.

  10. BLOWER MOTOR WITH FAN SUB-ASSEMBLY

    The blower motor with fan sub-assembly has a built-in blower controller, and is controlled using duty control performed by the air conditioning amplifier assembly.

  11. BUS CONNECTOR (AIR CONDITIONING HARNESS ASSEMBLY)


    1. BUS connectors are used in the wire harness that connects the servo motors to the air conditioning amplifier assembly.

      B000IN6E04

    2. Each BUS connector has a built-in communication/driver IC which communicates with the air conditioning amplifier assembly, 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.

      B000MPRE03

  12. 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 assembly based on the difference of the pulse phases. The BUS connector can detect the damper position and movement direction with these signals.

    B000LCQE04

  13. QUICK HEATER ASSEMBLY (w/ PTC Heater)


    1. General


      1. The quick heater assembly is located above the heater core in the air conditioning radiator assembly.

      2. The quick heater assembly 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.

    2. Quick Heater Assembly Operating Conditions


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

  14. ROOM TEMPERATURE SENSOR (COOLER THERMISTOR)

    The room temperature sensor (cooler thermistor) detects the cabin temperature based on changes in the resistance of its built-in thermistor and sends a signal to the air conditioning amplifier assembly.

  15. AMBIENT TEMPERATURE SENSOR (THERMISTOR ASSEMBLY)

    The ambient temperature sensor (thermistor assembly) detects the outside temperature based on changes in the resistance of its built-in thermistor and sends a signal to the air conditioning amplifier assembly.

  16. SOLAR SENSOR (AUTOMATIC LIGHT CONTROL SENSOR)


    1. The solar sensor (automatic light control sensor) consists of a photo diode, two amplifier circuits for the solar sensor (automatic light control sensor), and frequency converter circuit for the light control sensor.

    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 the LH and RH sides (2 directions) and outputs these sunlight strength signals to the air conditioning amplifier assembly.

      B000KTWE10

  17. AIR CONDITIONING PRESSURE SENSOR

    The air conditioning pressure sensor detects the refrigerant pressure and outputs it to the air conditioning amplifier assembly in the form of voltage changes.