AIR CONDITIONING SYSTEM


  1. SYSTEM CONTROL


    1. Control List


      1. The air conditioning system uses the following types of control.

        Control Outline
        Neural Network Control This control is capable of effecting 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 that is similar to a human brain.
        Outlet Air Temperature Control In compliance with the temperature set at the temperature control switch, the neural network control calculates the outlet temperature based on the input signals from various sensors. In addition, corrections in accordance with the signals from the evaporator temperature sensor and engine coolant temperature sensor are added to control the outlet air temperature.
        The temperature setting for the driver and front passenger is controlled independently in order to provide a separate vehicle interior temperature for the right and left side of the vehicle. Thus, air conditioning control that accommodates occupant preferences has been realized.
        Blower Control Controls the blower with fan motor sub-assembly in accordance with the airflow volume that has been calculated by the neural network control based on the input signals from various sensors.
        Pollen Removal Mode Control Activated by the pollen removal mode switch operation. Switches the air vent to the FACE mode. Sends air which has passed through the clean air filter to the area around the upper part of the bodies of the driver and front passenger. This air is filtered by the clean air filter in order to remove pollen.
        Air Inlet Control Automatically controls the air inlet control damper in accordance with the outlet temperature that has been calculated by the neural network control.
        Drives the servo motor (for air inlet) according to the operation of the air inlet control switch and moves the dampers to the FRESH or RECIRC position.
        Electric Inverter Compressor Control Compressor Speed Control The air conditioning amplifier assembly calculates the target speed of the compressor based on the target evaporator temperature (which is calculated by the temperature control switch, humidity sensor, room temperature sensor, ambient temperature sensor, and automatic light control sensor) and the actual evaporator temperature that is detected by the evaporator temperature sensor in order to control the compressor speed.
        The air conditioning amplifier assembly calculates the target evaporator temperature, which includes corrections based on the temperature control switch, humidity sensor, room temperature sensor, ambient temperature sensor, automatic light control sensor, and evaporator temperature sensor. Accordingly, the air conditioning amplifier assembly controls the compressor speed to an extent that would not inhibit the proper cooling performance or defogging performance.
        Turns the air conditioning ON automatically when the AUTO button is pressed when the blower is ON and the air conditioning is OFF.
        Decreases the compressor speed in order to ensure quietness when the vehicle is stopped or the engine is off.
        PTC Heater Control*1

        When the hybrid system is operating (READY), and the blower with fan motor sub-assembly is turned on, the air conditioning amplifier assembly turns on the quick heater assembly if the conditions listed below are met.

        - Engine coolant temperature is below specified temperature.

        - Outside temperature is below specified temperature.

        - Tentative air mix damper opening angle is above the specified value (MAX HOT).
        Electric Engine Water Pump Control The air conditioning amplifier assembly calculates the flow rate value required for the electric engine water pump assembly in accordance with the engine coolant temperature and air mix damper opening degree and sends it to the ECM.
        Eco Drive Mode Control When the ECO MODE switch is turned on, the air conditioning amplifier assembly limits the air conditioning system performance.
        Rear Window Defogger and Mirror Heater Control When the power switch is turned to ON (IG), and the rear window defogger switch is pushed, this system is activated to keep the defogger heater on for approximately 15 minutes.
        Front Wiper Deicer Control*2 Switches the front wiper deicer on for approximately 15 minutes when the front wiper deicer switch is pressed.

        *1: Models with PTC heater

        *2: Models with front wiper deicer

    2. Neural Network Control


      1. Previously, in automatic air conditioning systems without neural network control, the air conditioning amplifier determined the required outlet air temperature and blower air volume in accordance with the calculation formula that was 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. The air conditioning amplifier 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 ambient 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 neural network control.

        B0022S3E23

    3. Pollen Removal Mode Control


      1. When the pollen removal switch is pressed, the pollen removal mode control is activated. Then, the air vent is switched to the FACE mode and recirculated pollen free air flows in the area around the upper part of the bodies of the driver and front passenger.

      2. When the pollen removal switch signal is received by the air conditioning amplifier assembly, the air conditioning amplifier assembly controls the compressor with motor assembly, air inlet servo motor, air vent servo motor and blower motor as shown in the timing chart below.

      3. This control usually operates for approximately 3 minutes. However, when the outside temperature is low, it will operate for approximately 1 minute.

      4. After this control stops operating, the air conditioning amplifier assembly controls the air conditioning system using AUTO mode.

        B0022BYE25

    4. PTC Heater Control


      1. The on/off function of the quick heater assembly is controlled by the air conditioning amplifier assembly in accordance with the engine coolant temperature, engine speed, air mix setting, and electrical load (generator assembly power ratio).

      2. For example, the number of the operating quick heater assemblies varies depending on the engine coolant temperature, temperature as in the graph below:

        B0022TIE05
        *a Number of PTC Heater
        *b Engine Coolant Temperature

    5. Eco Drive Mode Control


      1. During eco drive mode control, the air conditioning amplifier assembly restricts the air conditioning system performance under specified conditions, thus improving fuel economy.

      2. Eco drive mode control is activated when the drive mode select is turned to ECO, and then restricts the air conditioning system performance as described below.

        Control Outline
        Inside/outside Air Switch Control Automatically switches the air inlet port to recirculation mode when the outside air temperature is equal to or higher than a predetermined temperature and reduces the power consumption.
        Blower Level Control Sets the blower level in AUTO mode lower than normal, and suppresses the power consumption.
        PTC Heater Control* Suppresses the power consumption.
        Heating Restriction Control Changes the air outlet temperature by entering ECO mode during heating and increases the amount of engine-off time when the drive mode is in ECO, thus improving fuel economy.
        Compressor Speed Restriction Control Restricts the maximum compressor speed during cooling and reduces the power consumption.

        *: Models with PTC heater

  2. CONSTRUCTION


    1. Air Conditioning Control Assembly


      1. A push-button type air conditioning control assembly is used.

      2. Temperature control switches for the driver and front passenger are provided on the air conditioning control assembly to enhance their ease of use.

      3. Along with the adoption of a pollen removal mode, a pollen removal switch is provided.

      4. On models with the navigation system, the air conditioning status is displayed on the multi-display (center instrument cluster finish panel assembly) and the air conditioning control assembly.

      5. On models with the navigation system, a Global Positioning System (GPS) clock is provided.

      6. On models with the navigation system, in addition to the air conditioning control assembly, the remote Touch has been adopted, ensuring remote control operation of items on the center instrument cluster finish panel assembly (multi-display), allowing for excellent operability and display visibility.

        B00229JE03
        Text in Illustration
        *A Models with Navigation System *B Models without Navigation System
        *1 Multi-Display *2 Air Conditioning Control Assembly
        *3 Remote Touch - -

    2. Air Conditioning Unit


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

      2. The No. 1 cooler evaporator sub-assembly and heater radiator unit sub-assembly are mounted transversely to achieve a compact and lightweight form.

      3. A bus connector is used in the wire harness connection that connects the servo motor to the air conditioning amplifier assembly.

        B0022RNE03
        Text in Illustration
        *1 Heater Radiator Unit Sub-assembly *2 No. 1 Cooler Evaporator Sub-assembly
        *a Front *b Side View
        *c Top View - -

      4. The partial recirculation system is used. This system has an air inlet control door (sub) in the cabin side of the air inlet duct. Thus, it is able to cycle a small volume of recirculated air even in the FRESH mode, thus ensuring heating and air conditioning performance. When the blower switch is on, the suction force of the blower fan opens this air inlet control door (sub).

        B0022CQE03
        Text in Illustration
        *1 Air Inlet Control Door *2 Fresh Air
        *3 Recirculated Air *4 Air Inlet Duct
        *5 Air Inlet Control Door (Sub) *6 To Blower

    3. No. 1 Cooler Evaporator Sub-assembly


      1. A Revolutionary super-slim Structure (RS) type evaporator is used. Placing the tanks at the top and the bottom of the evaporator and adopting a micropore tube construction has provided the following benefits:


        • Improved heat exchange efficiency

        • More uniform temperature distribution

        • A thinner evaporator

          B0022IWE03
          Text in Illustration
          *1 Tank *2 Cooling Fin
          *3 Micropore Tube - -

    4. Evaporator Temperature Sensor (No. 1 Cooler Thermistor)


      1. The evaporator temperature sensor (No. 1 cooler thermistor) detects the temperature of the cooled air immediately past the evaporator in the form of resistance changes, and outputs this data to the air conditioning amplifier assembly.

    5. 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.

        B0022OT

    6. Quick Heater Assembly


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

        B0022G4E01
        Text in Illustration
        *1 PTC Heater *2 Aluminum Fin
        *3 Brass Plate *4 PTC Element

    7. Blower with Fan Motor Sub-assembly


      1. The blower with fan motor sub-assembly has a built-in blower controller which is controlled by the air conditioning amplifier assembly.

      2. A brushless motor is adopted for the blower with fan motor sub-assembly. This achieves low noise and better use of space, and enhances characteristics of the blower motor, which enables blower level to be increased.

    8. Bus Connector


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

        B0022PSE04
        Text in Illustration
        *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 bus connector 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.

        B0022PRE26
        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 - -

    9. Servo Motor


      1. In contrast to the previous type that detects the position by way of a potentiometer voltage, the pulse pattern type servomotor detects the relative position by way of the 2-bit on/off signals.

      2. The forward and reverse revolutions of this motor are detected by way of 2 phases, A and B, which output 4 types of patterns. The air conditioning amplifier assembly counts the number of pulse patterns in order to determine the stopped position.

        B0022GNE33

    10. Clean Air Filter


      1. A pollen removal type filter is used. This filter is made of polyester and excels in the removal of dust and pollen. Because the filter is made of polyester it can be disposed of easily as a non-hazardous combustible material, a feature provided out of consideration for the environment.

        B0022GME04
        Text in Illustration
        *1 Clean Air Filter *2 Large Foreign Object Filter Layer
        *3 Electret Layer *4 Air Flow

    11. Cooler Condenser Assembly


      1. A Multi-Flow (MF) type condenser is used. The cooler condenser assembly consists of 2 cooling portions: a condensing portion and a super-cooling portion. These portions are integrated with a gas-liquid separator (modulator). This cooler condenser assembly uses a sub-cool cycle that offers excellent heat-exchange performance.

      2. In the sub-cool cycle, after the refrigerant passes through the condensing portion of the condenser, both the liquid refrigerant and the gaseous refrigerant that could not be liquefied are cooled again in the super-cooling portion. Thus, the refrigerant is sent to the evaporator in an almost completely liquefied state.

        B00229EE04
        Text in Illustration
        *1 Gaseous Refrigerant *2 Condensing Portion
        *3 Modulator *4 Desiccant
        *5 Filter *6 Super-cooling Portion
        *7 Liquid Refrigerant - -

        Tech Tips

        The point at which the air bubbles disappear in the refrigerant of the sub-cool cycle is lower than the proper amount of refrigerant with which the system must be filled. Therefore, if the system is recharged with refrigerant based on the point at which the air bubbles disappear, the amount of refrigerant would be insufficient. As a result, the cooling performance of the system would be affected. Overcharging the system with refrigerant will also lead to reduced performance. For the proper method of verifying the amount of refrigerant and for instructions on how to recharge the system with refrigerant. For details, refer to the Repair Manual.

        B0022DAE33
        *1 Proper Charge Amount
        *2 High Pressure
        *3 Point at which Bubbles Disappear
        *4 Amount of Refrigerant

    12. Compressor with Motor Assembly


      1. Along with the installation of the hybrid system, an ES27 type electric inverter compressor that is driven by a motor is used. The basic construction and operation of this compressor is the same as an ordinary scroll compressor, except that it is driven by an electric motor.

      2. The A/C inverter is integrated with the compressor.

      3. The electric motor is actuated by 3-phase alternating current created from the direct current (201.6 V) supplied to the A/C inverter. As a result, the air conditioning system is actuated without depending on the operation of the engine, thus realizing a comfortable air conditioning system and low fuel consumption.

      4. Due to the use of an electric inverter compressor, the compressor speed can be controlled at the required speed calculated by the air conditioning amplifier assembly. Thus, the cooling and dehumidification performance and power consumption have been optimized.

      5. Low-moisture permeation hoses are used for the suction and discharge hoses at the compressor in order to minimize the entry of moisture into the refrigeration cycle.

      6. The compressor is supplied with high-voltage direct current, and it uses high-voltage alternating current internally. If an open or short circuit occurs in the compressor, the power management control ECU will cut off the A/C inverter circuit.

        B0022RAE04
        Text in Illustration
        *1 A/C Inverter *2 Discharge Hose Port
        *3 Suction Hose Port - -

      7. The electric inverter compressor consists of a spirally wound fixed scroll and rotating scroll that form a pair, a brushless motor, an oil separator, a motor shaft and A/C inverter.

      8. The fixed scroll is integrated with the housing. Because the rotation of the shaft causes the rotating scroll to revolve while maintaining the same posture, the volume of the space that is partitioned by both scrolls varies to perform the suction, compression, and the discharge of the refrigerant gas.

      9. Locating the suction port directly above the scrolls enables direct suction, thus realizing improved suction efficiency.

      10. Containing a built-in oil separator, this compressor is able to separate the compressor oil that is intermixed with the refrigerant and circulates in the refrigeration cycle, thus realizing a reduction in the oil circulation rate.

      11. This inverter converts the HV battery nominal voltage of DC 201.6 V into AC and supplies power to operate the compressor.

        B0022SFE05
        Text in Illustration
        *1 A/C Inverter *2 Discharge Port
        *3 Motor Shaft *4 Rotating Scroll
        *5 Fixed Scroll *6 Oil Separator
        *7 Brushless Motor *8 Electric Inverter Compressor
        *9 A/C Inverter *10 HV Battery
        *11 Current Sensor *12 Power Supply Circuit
        *13 Gate Drive Circuit *14 Temperature Sensor
        *15 Voltage Sensor *16 Power Management Control ECU
        *17 Input/Output Interface *18 CPU
        *19 System Protection Control Circuit - -
        *a From Battery - -

        Note

        In order ensure proper insulation of the internal high-voltage portion of the compressor and the compressor housing, this model has adopted compressor oil (ND11) with a high level of insulation performance. Therefore, never use compressor oil other than the ND11 type compressor oil or its equivalent.

    13. Humidity Sensor


      1. A humidity sensor, in which the glass temperature sensor, glass surroundings temperature sensor and glass humidity sensor are integrated, is used.

      2. The glass temperature sensor detects the surface temperature of the windshield using the built-in thermistor attached to the back of the sensor board, and outputs the signal to the air conditioning amplifier assembly.

      3. The glass surroundings temperature sensor detects the air temperature near the windshield using the built-in thermistor, and outputs the signal to the air conditioning amplifier assembly.

      4. The glass humidity sensor converts a change in the electrostatic capacity between the electrodes by allowing the humidity-sensing film to adsorb and desorb moisture in the cabin, and outputs the signal to the air conditioning amplifier assembly.

    14. Room Temperature Sensor


      1. The room temperature sensor detects the room temperature based on changes in the resistance of its built-in thermistor. This signal is used by the air conditioning amplifier assembly.

    15. Ambient Temperature Sensor


      1. The ambient temperature sensor detects the ambient temperature based on changes in the resistance of its built-in thermistor. This signal is used by the air conditioning amplifier assembly.

    16. Automatic Light Control Sensor


      1. The automatic light control sensor consists of a photo diode, 2 amplifier circuits and a frequency converter circuit.

      2. The 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.

        B0022MJE33

    17. Air Conditioner Pressure Sensor


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

  3. OPERATION


    1. Mode Position and Door Operation

      B0022L7E03
      Text in Illustration
      *1 Center Defroster *2 Side Defroster
      *3 Fresh Air *4 Recirculated Air
      *5 Blower with Fan Motor Sub-assembly *6 Heater Radiator Unit Sub-assembly
      *7 No. 1 Cooler Evaporator Sub-assembly *8 Side Register
      *9 Front Footwell Register Duct *10 Rear Footwell Register Duct
      *11 Front Center Register - -
      *a To Driver Side *b To Passenger Side
      Control Door Operation Position Door Position Operation
      Air Inlet Control Door FRESH A Brings in fresh air.
      RECIRCULATION B Recirculates internal air.
      Air Mix Control Door

      MAX COLD to MAX HOT

      Temperature Setting

      C - D

      (C1 - D1)

      		 Varies the mixture ratio of warm air and cool air in order to regulate the temperature continuously between hot and cold.
      Mode Control Door B0022BF FACE F, I Air blows out of the front center register and side register ducts.
      B0022U8 BI-LEVEL F, H Air blows out of the front center register, side register and front and rear footwell register ducts.
      B0022DK FOOT E, G Air blows out of the front and rear footwell register and side register ducts. In addition, air blows out slightly from the center defroster and side defroster.
      B0022DN FOOT AND DEFROSTER E, H Defrosts the windshield through the center defroster, side defroster and side register ducts, while air is also blown out from the front and rear footwell register ducts.
      B0022SO DEFROSTER E, I Defrosts the windshield through the center defroster, side defroster and side register ducts.

    2. Air Outlets and Airflow Volume

      B0022E8E03
      Text in Illustration
      *a Models with Audio Amplifier - -
      Indication Mode Face Footwell Defroster
      Center Side Front Rear Center Side
      A B C D E F
      B0022BF FACE B0022R0 B0022R0 - - - -
      B0022U8 BI-LEVEL B0022HN B0022HN B0022NB B0022NB - -
      B0022DK FOOT - B00229H B0022NB B0022NB B00229H B00229H
      B0022DN FOOT AND DEFROSTER - B0022HN B0022HN B0022HN B0022HN B0022HN
      B0022SO DEFROSTER - B00229H - - B0022R0 B0022R0

      The size of the circle ○ indicates the proportion of airflow volume.

    3. Cooler Compressor Operation


      1. Suction Operation

        As the capacity of the compression chamber, which is created between the rotating scroll and the fixed scroll increases in accordance with the revolution of the rotating scroll, refrigerant gas is drawn in from the intake port.

      2. Compression Operation

        From the state at which the suction process has been completed, as the revolution of the rotating scroll advances further, the capacity of the compression chamber decreases gradually. Consequently, the refrigerant gas that has been drawn in becomes compressed gradually and is sent to the center of the fixed scroll. The compression of the refrigerant gas is completed when the rotating scroll completes approximately 2 revolutions.

      3. Discharge Operation

        When the compression of the refrigerant gas is completed and the refrigerant pressure becomes high, the refrigerant gas discharges through the discharge port located in the center of the fixed scroll by pushing the discharge valve.

        B00229WE13
        Text in Illustration
        *1 Intake Port *2 Fixed Scroll
        *3 Rotating Scroll *4 Discharge Port
        *a Suction *b Compression
        *c Discharge - -

  4. DIAGNOSIS


    1. The air conditioning amplifier assembly has a diagnosis function. It stores a record of any air conditioning system failures in its memory in the form of Diagnostic Trouble Codes (DTCs).

    2. There are 2 methods for reading DTCs. One is to use the intelligent tester, and the other is to read the DTCs using the air conditioning control assembly*1 or center instrument cluster finish panel assembly (multi display)*2. For details, refer to the Repair Manual.

      *1: Models without navigation system

      *2: Models with navigation system