AIR CONDITIONING SYSTEM

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 temperature sensor) thermistor, outside temperature sensor (thermistor assembly), and solar sensor (automatic light control sensor)) and the actual evaporator temperature detected by the evaporator temperature sensor (cooler thermistor No. 1). Then, the air conditioning amplifier assembly transmits the target speed to the power management control ECU. The power management control ECU controls the air conditioning inverter based on the target speed data in order to control the compressor with motor assembly 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 temperature control switch, cooler (room temperature sensor) thermistor, outside temperature sensor (thermistor assembly), solar sensor (automatic light control sensor), and evaporator temperature sensor (cooler thermistor No. 1). Accordingly, the air conditioning amplifier assembly 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.

3. The compressor with motor assembly 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 with motor assembly, the power management control ECU will cut off the air conditioning inverter circuit.

   

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 compressor with motor assembly, blower damper servo sub-assembly (recirculation/refresh), air conditioning radiator damper servo sub-assembly No. 2 (mode) 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.

   

PTC Heater Control (Models with PTC Heater System)

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 PTC heater varies depending on the engine coolant temperature, temperature as in the graph below:

   

   *a	Number of PTC Heater
   *b	Engine Coolant Temperature

Air Conditioning Radiator Assembly

1. A semi-center location air conditioning radiator assembly is used, in which the cooler evaporator sub-assembly No. 1 and heater radiator unit sub-assembly are mounted horizontally.

   

   Text in Illustration

   *1

   Heater Radiator Unit Sub-assembly

   *2

   Cooler Evaporator Sub-assembly No. 1

2. A 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).

   

   Text in Illustration

   *1	Air Inlet Control Door	*2	Air Inlet Control Door (Sub)
   *a	Fresh Air	*b	Recirculated Air
   *c	To Blower Fan	-	-

Cooler Evaporator Sub-assembly No. 1 (Models for Europe)

1. The Revolutionary super-slim Structure (RS) type cooler evaporator sub-assembly No. 1 is used. Placing the tank at the top and the bottom of the evaporator and using a micropore tube construction provides the following benefits:

   
   

   • Improved heat exchange efficiency

   • More uniform temperature distribution

   

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   *1	Top Tank	*2	Bottom Tank
   *3	Upwind Side	*4	Downwind Side

Cooler Evaporator Sub-assembly No. 1 (Models for Australia and Destination Package for Hong Kong and New Zealand)

1. The Ejector Cycle System (ECS) type cooler evaporator sub-assembly No. 1 is used.

2. By placing the tanks at the top and the bottom of the evaporator unit and adopting a micropore tube construction, the following effects have been realized:

   
   

   • The heat exchanging efficiency has been improved.

   • The temperature distribution has been made more uniform.

   • The evaporator has been made thinner.

3. The ejector is provided in the top tank of the cooler evaporator sub-assembly No. 1.

   

   Text in Illustration

   *1	Top Tank (Built-in Ejector)	*2	Bottom Tank
   *3	Upwind Side	*4	Downwind Side

Bus Connector

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

   

   Text in Illustration

   *A	LHD Models	*B	RHD Models
   *1	Bus Connector	*2	Air Conditioning Harness Assembly
   *a	To Air Conditioning Amplifier Assembly	*b	To Evaporator Temperature Sensor (Cooler Thermistor No. 1)

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.

   

   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	-	-

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.

   

Clean Air Filter (Air Refiner Element)

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.

   

   Text in Illustration

   *1	Clean Air Filter (Air Refiner Element)	*2	Large Foreign Object Filter Layer
   *3	Electret Layer	*4	Air Flow

Condenser with Receiver Assembly

1. A Multi-Flow (MF) type condenser is used. The condenser with receiver 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 condenser with receiver 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.

   

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   *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.

   

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

Compressor with Motor Assembly

1. Along with the installation of the hybrid system, an ES27 type compressor with motor assembly 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 air conditioning inverter is integrated with the compressor with motor assembly.

3. The electric motor is actuated by 3-phase alternating current created from the direct current (201.6 V) supplied to the air conditioning 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 a compressor with motor assembly, 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 with motor assembly 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 with motor assembly, the power management control ECU will cut off the air conditioning inverter circuit.

   

   Text in Illustration

   *1	Air Conditioning Inverter	*2	Discharge Hose Port
   *3	Suction Hose Port	-	-

7. The compressor with motor assembly consists of a spirally wound fixed scroll and rotating scroll that form a pair, a brushless motor, an oil separator, a motor shaft and air conditioning 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.

    

    Text in Illustration

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

    Note

    In order to ensure proper insulation of the internal high-voltage portion of the compressor with motor assembly 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.

Mode Position and Door Operation

Control Damper	Operation Position		Damper Position	Operation
Air Inlet Control Damper	FRESH		A	Brings in fresh air.
	RECIRCULATION		B	Recirculates internal air.
Air Mix Control Damper	MAX COLD-MAX HOT		C, D	Varies the mixture ratio of warm air and cool air in order to regulate the temperature continuously from HOT to COLD.
Mode Control Damper		FACE	E, J	Air blows out of the center registers and side registers.
		BI-LEVEL	F, J	Air blows out of the center registers, side registers, and front and rear footwell register ducts.
		FOOT	F, I	Air blows out of the front and rear footwell registers ducts and side registers. In addition, air blows out slightly from the front defroster and side defrosters.
		FOOT/DEF	F, H	Defrosts the windshield through the center defroster, side defrosters and side registers, while air is also blown out from the front and rear footwell register ducts.
		DEF	E, G	Defrosts the windshield through the center defroster, side defrosters and side registers.

Air Outlets and Airflow Volume

Indication	Mode	Face		Footwell		Defroster
		Center	Side	Front	Rear	Center	Side
		A	B	C	C	D	E
	FACE			-	-	-	-
	BI-LEVEL					-	-
	FOOT	-
	FOOT AND DEFROSTER	-
	DEFROSTER	-		-	-

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

Ejector Cycle System Operation (Models for Australia and Destination Package for Hong Kong and New Zealand)

1. In the conventional refrigerant cycle, liquid refrigerant gas is sent into the cooler evaporator sub-assembly No. 1 using the cooler expansion valve, generating cold air. However, a rapid decrease in the refrigerant pressure forms swirls, causing energy loss. In this ejector cycle, the energy loss caused by the cooler expansion valve is utilized by the operation of the ejector that injects and expands a high-pressure refrigerant, thus improving energy consumption efficiency.

   

   

2. The ejector includes nozzle, mixing and diffuser portions.

3. The high temperature and pressure liquid refrigerant from the condenser with receiver assembly is introduced into the mixing section through the nozzle at high speeds because the nozzle is inwardly tapered. This decreases the refrigerant pressure in the vicinity of the nozzle, drawing low temperature and pressure gaseous refrigerant into the nozzle from the cooler evaporator sub-assembly No. 1. Thus, both refrigerants mix in the mixing section and pass into the diffuser section.

4. As the diffuser section is outwardly flared, the refrigerant flow rate in the diffuser decreases and the refrigerant pressure rises.

5. Through these operations, the refrigerant pressure in the cooler evaporator sub-assembly No. 1 on the downwind side can be constantly kept lower than that on the upwind side, creating the lower temperature conditions. Therefore, air cooled by the cooler evaporator sub-assembly on the upwind side can be further cooled by the downwind side, thus improving the efficiency of the cooler evaporator sub-assembly No. 1.