AIR CONDITIONING SYSTEM


  1. FUNCTION OF MAIN COMPONENTS


    1. The air conditioning system consists of the following parts:

      Component Function
      Air Conditioning Control Assembly Allows operation and adjustment of the air conditioning system via switches.
      Air Conditioning Amplifier Assembly Transmits and receives data between the switches and sensors.
      Compressor with Motor Assembly Performs suction, compression and discharge of refrigerant gas.
      Blower Motor with Fan Sub-assembly High magnetic force magnets and ball bearings are used to achieve a compact and lightweight assembly.
      Cooler Condenser Assembly A condenser is used to improve heat exchange efficiency.
      Heater Radiator Unit Sub-assembly A Straight Flow Aluminum (SFA)-II heater radiator is used for compactness and high performance.
      No. 1 Cooler Evaporator Sub-assembly A micropore tube construction evaporator is used.
      Evaporator Temperature Sensor (No. 1 Cooler Thermistor) Detects the temperature of the cool air past the No. 1 cooler evaporator sub-assembly and transmits the data to the air conditioning amplifier assembly.
      Ambient Temperature Sensor (Thermistor Assembly) Detects ambient temperature and outputs it to the air conditioning amplifier assembly.
      Cooler (Room Temperature Sensor) Thermistor Detects room temperature and outputs it to the air conditioning amplifier assembly.
      Automatic Light Control Sensor Detects the changes in the amount of solar energy and outputs them to the air conditioning amplifier assembly via the main body ECU (multiplex network body ECU).
      Air Conditioner Pressure Sensor Detects the refrigerant pressure and sends data to the air conditioning amplifier assembly.
      PTC Heater (Quick Heater Assembly)* Consists of Positive Temperature Coefficient (PTC) elements, aluminum fins, and brass plates.
      ECM Receives the signals from the engine coolant temperature sensor and transmits them to the air conditioning amplifier assembly.
      Hybrid Vehicle Control ECU Controls the compressor with motor assembly by signals from air conditioning amplifier assembly.
      Combination Meter Assembly Transmits the vehicle speed signal to the air conditioning amplifier assembly.
      Main Body ECU (Multiplex Network Body ECU) Receives the signals from the automatic light control sensor and transmits them to the air conditioning amplifier assembly.

      *: Cold area specification models

  2. SYSTEM CONTROL


    1. Control List

      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 setting 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 (No. 1 cooler thermistor) and the engine coolant temperature sensor are added to control the outlet air temperature.
      Left and Right Independent Control 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 sides of the vehicle. Thus, air conditioning control that accommodates occupant 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 the neural network control based on the input signals from various sensors.
      Air Outlet Control Automatically switches the outlets in accordance with the outlet mode ratio that has been calculated by the neural network control based on the input signals from various sensors.
      Air Inlet Control Automatically controls the air inlet control damper in accordance with the airflow volume that has been calculated by the neural network control.
      Refrigerant Volume Detection Control Judges a shortage of refrigerant volume based on signals from each sensor and informs the user by turning off the indicator light of the A/C switch.
      Compressor Control The air conditioning amplifier assembly calculates the target speed of the compressor based on the target evaporator temperature (which is calculated by the room temperature sensor, ambient temperature sensor and solar sensor) and the actual evaporator temperature that is detected by the evaporator temperature sensor in order to control the compressor speed.
      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*

      When the power switch is turned on (IG), and the blower motor is turned on, the air conditioning amplifier assembly turns on the PTC heater (quick heater assembly) if the following conditions are met.


      • Engine coolant temperature is below specified temperature.

      • Ambient temperature is below specified temperature.

      • Tentative air mix damper opening angle is above the specified value (MAX HOT).

      ECO Drive Mode Control
      • When ECO drive mode is selected, the air conditioning amplifier assembly enters ECO air conditioning mode.

      • Pressing the FAST ECO switch cancels the ECO air conditioning mode.

      ECO Air Conditioning Mode Control When the FAST ECO switch is pushed with a mode other than ECO drive mode selected, the drive mode switches to ECO air conditioning mode.
      Blower Customization Control During automatic air conditioning operation, the air volume can be adjusted in 3 levels using the FAST ECO switch: MEDIUM → ECO (small air volume) → FAST (large air volume).
      Electric Power Control When the vehicle voltage is below the specified level, the air conditioning amplifier assembly saves the power source of some systems in accordance with the voltage signal from the hybrid vehicle control ECU.
      Parking Fresh Control By automatically switching to fresh air mode when the vehicle is parked. Ventilation of the parked vehicle is facilitated and outside air is introduced into the air conditioner unit assembly.
      Diagnosis A Diagnostic Trouble Code (DTC) is stored in memory when the air conditioning amplifier assembly detects a problem in the air conditioning system.

      *: Cold area specification models

    2. Neural Network Control


      1. In the previous automatic air conditioning system, the air conditioning amplifier assembly determined the required outlet air temperature and blower air volume in accordance with a calculation formula that had 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, but extremely uncomfortable in a hot climate. Therefore, as a technique for performing a high level of control, a neural network is used 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, which effects control to provide enhanced air conditioning comfort.

      2. The neural network control consists of neurons in an input layer, an intermediate layer, and an 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 signals 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 this data 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 with fan sub-assembly in accordance with the control volumes that have been calculated by neural network control.

        A001M37E01
    3. Refrigerant Volume Detection Control


      1. The air conditioning amplifier assembly judges the volume of refrigerant from the ambient temperature, refrigerant pressure and the temperature of the cool air just past the No. 1 cooler evaporator sub-assembly. When the air conditioning amplifier assembly judges that there is a refrigerant shortage, it turns off the indicator light of the A/C switch. At that time, the compressor with motor assembly stops operating.

    4. ECO Air Conditioning Mode Control


      1. In ECO air conditioning mode control, there are two types, the normal air conditioning mode, and ECO air conditioning mode, which gives fuel efficiency an even higher priority. Under specific conditions, the air conditioning amplifier assembly operates at a reduced level of air conditioning performance in order to improve fuel efficiency. ECO air conditioning mode can be selected by operating the FAST ECO switch.

        Control Outline
        Inside/Outside Air Switch Control If the outside air temperature exceeds a certain limit, the mode switches to inside air recirculation.
        Blower Level Control In AUTO mode, the blower level is lowered to the specified value and control is performed. Also, when in warm-up control, the blower level decreases.
        Heater and Compressor Control The operation of the heater or the compressor with motor assembly is decreased, to a reserved operation level.

        • By pressing the FAST ECO switch, the air conditioning system can be turned on, but when the setting display of drive mode in multi-information display has been operated to set ECO drive mode, the air conditioning will also automatically enter ECO air conditioning mode control.

        • Pressing and holding the FAST ECO switch sets ECO air conditioning mode, and air conditioning control will be performed with fuel efficiency as an even higher priority (air conditioning will have more reserved operation).

        • If DEF mode is selected, air conditioning related ECO air conditioning mode control will be canceled in order to reduce fogging of the windows as quickly as possible. However, if DEF mode is canceled, ECO air conditioning mode control will be restored.

        • Pressing the FAST ECO switch again will cancel the ECO air conditioning mode control. Also, ECO air conditioning mode control may be canceled if another air conditioning system switch is operated, or if the power switch is turned off.

    5. Parking Fresh Control


      1. While parking, fresh air introduction mode is automatically selected to enhance ventilation and reduce any odor remaining in the air conditioning unit, thus odor during hybrid system start-up is minimized.

        A001LNXE04
  3. DIAGNOSIS


    1. The air conditioning amplifier assembly has a self-diagnosis function. It stores any operation malfunctions in the air conditioning system in memory in the form of Diagnostic Trouble Codes (DTCs). For details, refer to the Repair Manual.