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.
      Blower Control Controls the blower motor in accordance with the airflow volume that has been calculated by neural network control based on 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/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.
      Electric Inverter Compressor Control The air conditioning amplifier assembly calculates the target compressor speed based on the target evaporator temperature (calculated from the temperature control switch, cooler (room temp. sensor) thermistor, thermistor assembly, and cooler (solar sensor) thermistor) and the actual evaporator temperature detected by the No. 1 cooler thermistor in order to control the compressor speed.
      The air conditioning amplifier assembly calculates the target evaporator temperature, which includes corrections based on the cooler (room temp. sensor) thermistor, thermistor assembly, cooler (solar sensor) thermistor, and No. 1 cooler thermistor. Accordingly, the air conditioning amplifier assembly controls the compressor speed to an extent that does not inhibit proper cooling performance or defogging performance.
      Turns the A/C on automatically when the AUTO button is pressed when the blower is on and the A/C is off.
      Decreases the compressor speed in order to ensure quietness when the vehicle is stopped or the engine is off.
      Defroster Control Defroster control logic is used to improve defroster performance.
      PTC Heater Control*2

      When the hybrid system is operating (READY), and the blower motor with fan sub-assembly is turned on, the air conditioning amplifier assembly turns on the PTC heater assembly (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).
      Rear Defogger Control

      Refer to Rear Defogger System.

      Click here

      Blower Customize During automatic air conditioning operation, the air volume can be adjusted in 3 levels using the FAST SOFT switch: MEDIUM → SOFT (small air volume) → FAST (large air volume).
      ECO Mode Control When the combination switch assembly (ECO switch) is turned on, the air conditioning amplifier assembly limits the air conditioning system performance.
      Diagnosis A Diagnostic Trouble Code (DTC) is stored in memory when the air conditioning amplifier assembly detects a problem with the air conditioning system.

      • *1: for Dual Type

      • *2: w/ PTC Heater

  2. NEURAL NETWORK CONTROL


    • In 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.

    A00YPA4E01

  3. MODE POSITION AND DAMPER OPERATION


    1. Mode Position and Damper Operation

      A00YN9HC03
      *a Air also blows out of the side registers *b Air also blows out of the side registers and defrosters
      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 Varies the mixture ratio of warm air and cool air in order to regulate the temperature continuously between hot and cold.
      Air Outlet Control Damper

      DEF

      A00YMTZ       		E, I Air blows out of the center defroster, side defrosters and side registers.

      FOOT / DEF

      A00YMX6       		E, H Air blows out of the front footwell register ducts, side registers and center defroster.

      FOOT

      A00YPVC       		E, G Air blows out of the side registers, front footwell register ducts. In addition, air blows out slightly from the center defroster and side defrosters.

      BI-LEVEL

      A00YPX9       		F, H Air blows out of the front footwell register ducts, front center registers and side registers.

      FACE

      A00YPB6       		F, I Air blows out of the front center registers and side registers.

  4. AIR OUTLETS AND AIRFLOW VOLUME


    1. Air Outlets and Airflow Volume

      A00YO89E01
      Indication Mode FACE FOOT DEF
      CTR SIDE C D
      A B
      A00YPB6 FACE A00YMZQ A00YMZQ A00YNHB A00YNHB
      A00YPX9 B/L A00YPE4 A00YPE4 A00YPE4 A00YNHB
      A00YPVC FOOT A00YNHB A00YNTP A00YPE4 A00YNTP
      A00YMX6 F/D A00YNHB A00YNTP A00YPE4 A00YNTP
      A00YMTZ DEF A00YNHB A00YNTP A00YNHB A00YPE4

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

  5. COMPRESSOR WITH MOTOR ASSEMBLY


    1. General

      Tech Tips

      In order to ensure the proper insulation of the internal high-voltage portion of the compressor and the compressor housing, this vehicle has adopted a compressor oil (ND-OIL 11) with a high level of insulation performance. Therefore, never use a compressor oil other than ND-OIL 11 type compressor oil or its equivalent.


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

      2. The Air Conditioning (A/C) inverter is integrated with the compressor.

      3. The electric motor is actuated by 3-phase alternating current (244.8 V) supplied by the A/C inverter. As a result, the air conditioning control system on this vehicle 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 uses high-voltage alternating current. If a short or open circuit occurs in the compressor, the power management control ECU will cut off the A/C inverter circuit in order to stop the power supply to the compressor motor.

    2. Compressor Speed Control


      1. The air conditioning amplifier assembly calculates the target compressor speed based on the target evaporator temperature (calculated from the temperature control switch, cooler (room temp. sensor) thermistor, thermistor assembly, and cooler (solar sensor) thermistor) and the actual evaporator temperature detected by the No. 1 cooler thermistor. Then, the air conditioning amplifier assembly transmits the target speed to the power management control ECU. The power management control ECU controls the A/C inverter based on the target speed data in order to control the compressor to a speed that suits the operating condition of the air conditioning system.

      2. The air conditioning amplifier assembly calculates the target evaporator temperature, which includes corrections based on the cooler (room temp. sensor) thermistor, thermistor assembly, cooler (solar sensor) thermistor, and No. 1 cooler thermistor. Accordingly, the air conditioning amplifier assembly controls the compressor speed to an extent that does not inhibit proper cooling performance or defogging performance. As a result, comfort and low fuel consumption can be realized.

  6. NO. 1 COOLER THERMISTOR

    The No. 1 cooler thermistor detects the temperature of the cool air immediately after the evaporator in the form of resistance changes, and outputs it to the air conditioning amplifier assembly.

  7. BLOWER MOTOR WITH FAN SUB-ASSEMBLY

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

  8. 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.

      A00YNVZC06
      *a For example *b

      Bus Connector

      (to Air Inlet Control Servo Motor Sub-assembly)
      *c

      Bus Connector

      (to Air Outlet Control Servo Motor Sub-assembly)

      		 *d

      Bus Connector

      (to Air Mix Control Servo Motor Sub-assembly)
      *e to Air Conditioning Amplifier Assembly *f to No. 1 Cooler Thermistor

    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.

      A00YPMNE13

  9. SERVO MOTOR

    A 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.

    A00YPQVE11

  10. PTC HEATER ASSEMBLY (QUICK HEATER ASSEMBLY)


    1. General


      1. The PTC heater assembly (quick heater assembly) is located above the heater core in the air conditioning unit.

      2. The PTC heater assembly (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.

        A00YN71C02
        *1 PTC Heater Assembly (Quick Heater Assembly) *a Brass Plate
        *b PTC Element *c Aluminum Fin

    2. PTC Heater Assembly (Quick Heater Assembly) Operating Conditions


      1. The PTC heater assembly (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).

  11. ECO MODE CONTROL

    Under the control of ECO mode, the air conditioning amplifier assembly restricts the air conditioning system performance under specified conditions, thus improving fuel economy.

  12. COOLER (ROOM TEMP. SENSOR) THERMISTOR

    The cooler (room temp. sensor) 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.

  13. THERMISTOR ASSEMBLY

    The 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.

  14. COOLER (SOLAR SENSOR) THERMISTOR

    The cooler (solar sensor) thermistor detects (in the form of changes in the current that flows through the built-in photo diode) the changes in the amount of sunlight and outputs these sunlight strength signals to the combination meter assembly.

  15. AIR CONDITIONER PRESSURE SENSOR

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