Heating and Air Conditioning: Description and Operation

AIR CONDITIONING: AIR CONDITIONING SYSTEM: SYSTEM DESCRIPTION

SYSTEM DESCRIPTION

1. GENERAL
(a) The air conditioning system has the following features:
- An ES34 type electric inverter compressor (compressor with motor assembly) is used on the vehicle. This compressor is driven by the alternating current that is supplied by the A/C inverter, which is integrated with the compressor. As a result, the air conditioning system is actuated.
- A compact, lightweight, and highly efficient electrical water pump is used in order to ensure the proper heater performance while the engine is stopped.
- The optional multi-zone automatic climate control system (controlled by the neural network) is available on this vehicle. When the 4-ZONE switch is ON, the temperature, airflow mode and airflow volume of each of the 4 seats (driver, front passenger, rear left, rear right) is automatically adjusted.
- As a standard, the front seat independent temperature climate control system (controlled by the neural network) is in this vehicle. A non-sliding type film damper is used to provide independent airflow volume for the right and left side of the vehicle.
- The registers on the center pillars help improve airflow to the rear seats.
- As a standard, the HV battery cooling unit is available on this vehicle.
- For vehicles with the rear cooler, there are roof and roof side air ducts, and independent temperature and airflow mode adjustments are automatically performed.
- The rear cooler unit has a rear seat independent temperature climate control system, an odor filter for the air purification function, and a cool box.
- For the long body VIP specification with ottoman, an infrared ray sensor unit is installed. The infrared ray sensor unit detects the body temperature of the rear seat passenger, compares the body temperature to a specified setting, and attempts to decrease the temperature difference.
- The Positive Temperature Coefficient (PTC) heater system contains a PTC heater that heats the air that has passed through the heater core to ensure proper heater performance.
- A compact, lightweight, and highly efficient straight flow (full-path flow) aluminum heater core is used.
- The room temperature sensor has a humidity sensor function in order to optimize the amount of dehumidification during the operation of the air conditioning system.
- The micro dust and pollen filter control is used to remove pollen in the area around the upper areas of the driver and front passenger seats.
- The air conditioning amplifier is equipped with a self diagnosis function. If there is a malfunction in the system, it stores the DTCs (Diagnostic Trouble Codes) in its memory.

2. MODE POSITION AND DAMPER OPERATION

















HINT: *: While the HV battery assembly is being cooled (HV battery cooler unit in operation), the compressor may turn ON even if the A/C switch is OFF or air may blow out though the blower switch is OFF. This does not indicate a malfunction.









3. AIR OUTLETS AND AIRFLOW VOLUME









HINT:
- The size of the circle indicates the proportion of airflow volume.
- FACE U: Air flows from registers only
- FACE L: Air flows from registers and footwells
- B/L U: Standard B/L mode
- B/L L: B/L mode in which large amount of air flows from footwells
- FOOT (DEF=0): FOOT mode where no air flows from defroster
- FOOT D: FOOT mode in which large amount of air flows from defroster
- FOOT R: FOOT mode in which large amount of air flows from rear footwells
- FOOT F: Standard FOOT mode
- F/D: Standard FOOT / DEF mode
- DEF: Standard DEF mode









HINT: The size of the circle indicates the proportion of airflow volume.

4. COMPRESSOR

General

- Along with the installation of the hybrid unit on the vehicle, an ES34 electric inverter compressor that is driven by a built-in DC 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.
- The A/C inverter is integrated with the compressor.
- The electric motor is actuated by the 3-phase alternating current power (288 V) supplied by the A/C inverter. As a result, the air conditioner control system on the vehicle is actuated.
- 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.
- 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.
- The compressor uses high-voltage alternating current. If a short or open circuit occurs in the compressor wiring harness, the hybrid vehicle control ECU will cut off the A/C inverter circuit in order to stop the power supply to the compressor.

Service Tip:
In order to ensure proper insulation of the internal high-voltage portion of the compressor and the compressor housing, use ND-OIL 11 compressor oil (which has a high level of insulation performance) in the vehicle. Never use a compressor oil other than ND-OIL 11.

Construction

- The electric inverter compressor consists of a spirally wound fixed scroll and variable scroll that form a pair, a brushless motor, oil separator, motor shaft and A/C inverter.
- The fixed scroll is integrated with the housing. Because the rotation of the shaft causes the variable scroll to revolve while maintaining the same position, the volume of the space that is partitioned by both scrolls varies to perform the suction, compression, and the discharge of the refrigerant gas.
- The suction port is located directly above the scrolls, enabling direct suction.
- 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.
- This inverter converts the HV battery's nominal voltage of DC 288 V into AC 288 V and supplies power to operate the compressor.





Electric Inverter Compressor Control

- The air conditioning amplifier calculates the target compressor speed based on the target evaporator temperature (calculated from the room temperature sensor, humidity sensor, ambient temperature sensor, and solar sensor (automatic light control sensor)) and the actual evaporator temperature detected by the evaporator temperature sensor. Then, the air conditioning amplifier transmits the target speed to the hybrid vehicle control ECU and controls the A/C inverter based on the target speed data in order to adjust the compressor to a speed that suits the operating condition of the air conditioning system.
- The air conditioning amplifier calculates the target evaporator temperature, which includes corrections based on the vehicle interior humidity (which is obtained from the humidity sensor) and the windshield glass inner surface humidity (which is calculated from the humidity sensor, solar sensor (automatic light control sensor), room temperature sensor, mode damper position, and wiper operation condition). Accordingly, the air conditioning amplifier controls the compressor speed to an extent that does not inhibit the proper cooling performance or defogging performance.





AIR CONDITIONING: AIR CONDITIONING SYSTEM: SYSTEM DIAGRAM

SYSTEM DIAGRAM





Communication table













HINT:
- *1: w/ Navigation System (for HDD)
- *2: w/ Navigation System (for DVD)
- *3: w/o Navigation System