Heating and Air Conditioning: Description and Operation

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: SYSTEM DIAGRAM

Communication Table

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: SYSTEM DESCRIPTION

1. GENERAL

The air conditioning system has the following controls.

(a) NEURAL NETWORK CONTROL

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

(b) MICRO DUST AND POLLEN FILTER MODE CONTROL

(1) When the micro dust and pollen filter switch is pressed, the micro dust and pollen filter 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 micro dust and pollen filter switch signal is received by the air conditioning amplifier assembly, the air conditioning amplifier assembly controls the A/C compressor, 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.

Text in Illustration

(1) Mode Position and Damper Operation

Functions of Main Dampers

(d) AIR OUTLETS AND AIRFLOW VOLUME

(1) Air Outlets and Airflow Volume

(1) The size of each circle o indicates the ratio of airflow volume.

(e) MEMORY CALL CONTROL

(1) The air conditioning amplifier assembly stores the air conditioning settings for each memory number when the power switch is turned off.

(2) The main body ECU (multiplex network body ECU) converts the key ID code into a memory number, stores it and sends the converted signal to the air conditioning amplifier assembly.

(3) The air conditioning amplifier assembly stores the memory number and air conditioning settings.

(4) When the doors are unlocked, the certification ECU (smart key ECU assembly) recognizes the key ID code and sends the key ID code to the main body ECU (multiplex network body ECU).

(5) Upon receiving the key ID code signal, the main body ECU (multiplex network body ECU) converts the signal into a memory number signal and sends it to the air conditioning amplifier assembly.

(6) Then the air conditioning amplifier assembly recalls the stored air conditioning settings based on the memory number signal when the power switch is turned on (IG).

(7) The following air conditioning system settings can be memorized:

HINT
Memory call control can be cancelled or re-enabled using the Techstream. When a new key is added, the key ID code registration is necessary.

(f) COMPRESSOR WITH MOTOR ASSEMBLY

(1) General

HINT
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 (ND11) with a high level of insulation performance. Therefore, never use a compressor oil other than the ND11 type compressor oil or its equivalent.

1 Along with the installation of the hybrid unit 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 the 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. 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 wiring harness, 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 calculates the target compressor speed based on the target evaporator temperature (calculated from the temperature control switch, room temperature sensor, ambient temperature sensor, and solar sensor) and the actual evaporator temperature detected by the evaporator temperature sensor. Then, the air conditioning amplifier 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 calculates the target evaporator temperature, which includes corrections based on the room temperature sensor, outside temperature sensor, solar sensor, and evaporator temperature sensor. Accordingly, the air conditioning amplifier controls the compressor speed to an extent that does not inhibit the proper cooling performance or defogging performance. As a result, comfort and low fuel consumption can be realized.

(g) HEATER WATER PUMP

(1) This vehicle uses an heater water pump for air conditioning. This provides a stable heater performance even if the engine is stopped because of a function of the hybrid control system.

(2) This vehicle uses a new type of electrical water pump in which the water flow resistance has been reduced.

(h) EVAPORATOR TEMPERATURE SENSOR

The evaporator temperature sensor 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.

(i) PLASMACLUSTER (ION GENERATOR) CONTROL (w/ Plasmacluster Ion Generator)

(1) General:

1 A Plasmacluster (ion generator) is provided inside the air duct of the side register on the driver seat side to improve the air quality and comfort in the cabin.

2 This generator is controlled by the air conditioning amplifier and operates when the Plasmacluster generator switch is pressed.

NOTICE:
* The Plasmacluster (ion generator) uses a high voltage, which is hazardous. Therefore, if the Plasmacluster (ion generator) requires repairs, be sure to have them done at an authorized dealer.
* Do not apply any type of spray (such as a cleaning solvent or hair spray) or stick any foreign matter into the Plasmacluster ion outlet, as this could cause improper operation or a malfunction.
* After use, dust may accumulate around the side register on the driver seat side. If this occurs, press the OFF switch on the A/C control assembly to stop the blower motor before cleaning the area.
* It is normal for the Plasmacluster (ion generator) to emit a slight sound during operation. This sound is created when electrons collide with the electrode while Plasmacluster ions are being generated.
HINT
PlasmaclusterTM, plasmacluster, and plasmacluster ions are a trademark of the SHARP Corporation.

(2) Operation:

1 The Plasmacluster (ion generator) produces positive and negative ions from the water molecules (H2O) and oxygen molecules (O2) in the air, and emits them into the air. These ions reduce airborne germs.

(j) ECO MODE CONTROL

(1) Under the control of eco mode, the air conditioning amplifier restricts the air conditioning system performance under specified conditions, thus improving fuel economy

(2) Eco mode control is activated when the ECO MODE switch provided inside the integration control and panel sub-assembly is pressed, and then restricts the air conditioning system performance as described below.

(k) BLOWER MOTOR

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

(2) The rear blower motor is controlled by the air conditioning amplifier via a blower motor controller using duty control.

(l) BUS CONNECTOR (AIR CONDITIONING HARNESS)

(1) A BUS connector is used in the wire harness connection that connects the servo motor from the air conditioning amplifier.

(2) Each BUS connector has a built-in communication/driver IC which communicates with each servo motor connector, 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.

(m) SERVO MOTOR

The pulse pattern type servo motor consists of a printed circuit board and a servo motor. The printed circuit board has 3 contact points, and can transmit 2 ON-OFF signals to the air conditioning amplifier based on the difference of the pulse phases. The BUS connector can detect the damper position and movement direction with these signals.

(n) ROOM TEMPERATURE SENSOR (BUILT-IN HUMIDITY SENSOR)

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

(2) A humidity sensor function has been added to the room temperature sensor. By enabling the detection of humidity in the vehicle interior, this function optimizes the amount of dehumidification effort during the operation of the A/C system. As a result, the power consumption of the compressor has been reduced and a comfortable level of humidity has been realized in the vehicle interior.

(3) The humidity-sensing resistance film that is built into the humidity sensor absorbs and releases the humidity in the cabin. During the absorption and releasing processes, the humidity-sensing resistance film expands (during the absorption of humidity) and contracts (during drying). The clearance between the carbon particles in the humidity-sensing resistance film expands and contracts during absorption and drying, thus changing the resistance between the electrodes. The air conditioning amplifier determines the humidity in the cabin through the changes in the output voltage of the humidity sensor that are caused by the resistance between the electrodes.

(o) AMBIENT TEMPERATURE SENSOR

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

(p) SOLAR SENSOR

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

(2) The solar 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.

(q) A/C PRESSURE SENSOR

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

(r) COOLER BLOWER ASSEMBLY

(1) A compact cooler blower assembly and air ducts are located in the center console. This allows cool air to flow to the rear seats, achieving comfortable cooling performance for the rear seat passengers.

(2) The cooler blower assembly has a built-in blower motor control which is controlled by the air conditioning amplifier assembly.

(3) The cooler blower assembly has an integrated 3 A fuse in its wire harness to prevent over current.

(s) Cooler Blower Switch

(1) The blower level can be adjusted by turning the knob on the bottom of the rear center register.

(2) A cooler blower switch is provided on the airflow adjusting knob mechanism. The switch turns the cooler blower assembly blower motor on and off in conjunction with the airflow adjusting knob position.