AIR CONDITIONING SYSTEM

Electric Inverter Compressor 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 thermistor (room temperature sensor), ambient temperature sensor (thermistor assembly), automatic light control sensor*1 and cooler thermistor (solar sensor)*2) and the actual evaporator temperature detected by the evaporator temperature sensor (No. 1 cooler thermistor). Then, the air conditioning amplifier assembly transmits the target speed to the hybrid vehicle control ECU. The hybrid vehicle control ECU controls the air conditioning inverter based on the target speed data in order to control the electric inverter compressor (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 thermistor (room temperature sensor), ambient temperature sensor (thermistor assembly), automatic light control sensor*1, cooler thermistor (solar sensor)*2 and evaporator temperature sensor (No. 1 cooler thermistor). 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 electric inverter compressor (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 electric inverter compressor (compressor with motor assembly), the hybrid vehicle control ECU will cut off the air conditioning inverter circuit.

   
   

   • *1: Models with automatic light control system

   • *2: Models without automatic light control system

   

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 past the No. 1 cooler evaporator sub-assembly. When the air conditioning amplifier assembly judges refrigerant shortage, it turns off the indicator light of the A/C switch. At that time, the electric inverter compressor (compressor with motor assembly) stops operating.

   

PTC Heater Control

1. The on/off function of the PTC heater (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.

2. For example, the number of the operating PTC heater (quick heater assembly) varies with engine coolant temperature as in the graph below.

   

   *a	Number of PTC Heater Operation
   *b	Engine Coolant Temperature

Air Conditioning Unit Assembly

1. The air conditioning unit consists of the heater radiator unit sub-assembly, No. 1 cooler evaporator sub-assembly, evaporator temperature sensor (No. 1 cooler thermistor), PTC heater (quick heater assembly) and damper servo sub-assemblies.

2. A semi-center location air conditioning unit, in which the heater radiator unit sub-assembly and No. 1 cooler evaporator sub-assembly are placed in the vehicle's longitudinal direction, is used.

   

   Text in Illustration

   *1	No. 1 Cooler Evaporator Sub-assembly	*2	Heater Radiator Unit Sub-assembly
   *a	Side View	*b	Top View
   	Front	-	-

3. A partial recirculation system is used. This system has an air inlet control door (sub) in the air inlet duct. Thus, it is able to cycle a small volume of recirculated air even in the FRESH mode, thus enhancing heating 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 (Sub)	*2	Air Inlet Control Door
   *3	Air Inlet Duct	-	-
   *a	RECIRC	*b	FRESH
   *c	To Blower Fan	-	-
   	Air Flow		Front

No. 1 Cooler Evaporator Sub-assembly

1. A Revolutionary super-Slim structure (RS) evaporator is used. By placing the tanks at the top and the bottom of the No. 1 cooler evaporator sub-assembly and by using a micropore tube construction, the following effects have been achieved:

   
   

   • Heat exchanging efficiency is ensured.

   • Temperature distribution is made uniform.

   • The No. 1 cooler evaporator sub-assembly is made thinner.

   

   Text in Illustration

   *1	Tank	*2	Micropore Tube
   *3	Cooling Fin	-	-

Servo Motor

1. In contrast to the previous type that detects the position by way of a potentiometer voltage, the pulse pattern type servo motor 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.

   

Cooler Condenser Assembly

1. A Global Inner-fin Condenser (GIC) is provided. This condenser has tubes with high-density inner fins, and outer fins which allow the use of thinner cores, contributing to the efficiency of cooling performance.

2. The cooler condenser 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 cooler condenser assembly uses a sub-cool cycle that offers excellent heat-exchange performance.

3. In the sub-cool cycle, after the refrigerant passes through the condensing portion of the cooler condenser assembly, 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 No. 1 cooler evaporator sub-assembly in an almost completely liquefied state.

   

   Text in Illustration

   *1	Modulator	*2	Desiccant
   *3	Filter	-	-
   	Condensing Portion		Super-cooling Portion
   	Gaseous Refrigerant		Liquid Refrigerant

Electric Inverter Compressor (Compressor with Motor Assembly)

1. An ES14 type electric inverter compressor (compressor with motor assembly) 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 electric inverter compressor (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.

3. The air conditioning inverter is integrated with the electric inverter compressor (compressor with motor assembly). This inverter operates the compressor on the HV battery. 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. 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. Locating the suction port directly above the scrolls enables direct suction, thus realizing improved suction efficiency. 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.

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.

   

   Text in Illustration

   *1	Rotating Scroll	*2	Fixed Scroll
   *3	Oil Separator	*4	Discharge Port
   *5	Brushless Motor	*6	Motor Shaft
   *7	Air Conditioning Inverter	*8	Discharge Hose Port
   *9	Suction Hose Port	-	-

   CAUTION:

   In order ensure the proper insulation of the internal high-voltage portion of the electric inverter compressor (compressor with motor assembly) and the compressor housing, this model 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.

Sub-cool Accelerator Type Tube (Models using HFO-1234yf refrigerant)

1. A sub-cool accelerator type tube is used to enhance air conditioning cooling performance. It functions as a heat exchanger by making use of the temperature difference between the gaseous refrigerant and liquid refrigerant.

2. The sub-cool accelerator type tube has a double-pipe construction. Helical grooves are embossed into the outer wall of the inner tube. Low-temperature and low-pressure gaseous refrigerant passes through the inner tube. High-temperature and high-pressure liquid refrigerant circulates between the inner tube and outer tube in the gap created by the grooves. Because of the temperature difference, heat exchange occurs.

3. The high-temperature and high-pressure liquid refrigerant circulate along the helical grooves causing the refrigerant to remain in contact with the outer wall of the inner tube for a longer period of time. This achieves an ample exchange of heat.

4. By lowering the temperature of the refrigerant that has passed through the cooler condenser assembly, more liquid refrigerant is supplied to the evaporator and the evaporator is also kept cooler. This enables an enhanced air conditioning cooling effect.

   

Clean Air Filter

1. A pollen removal type clean air filter is used to remove dust, pollen and other micron particles from air entering from outside the vehicle to provide a comfortable cabin of clean air. The clean air filter is installed in the upper section of the blower motor with fan sub-assembly.

   

   *1	Blower Motor with Fan Sub-assembly	*2	Clean Air Filter
   *3	Air Filter Case	*4	Pollen
   *5	Micron Particle	-	-
   *a	Image of Clean Air Filter	*b	Large Foreign Object Filter Layer
   *c	Electret Layer	-	-

PTC Heater (Quick Heater Assembly)

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

2. The PTC heater (quick heater assembly) consists of a Positive Temperature Coefficient (PTC) element, an aluminum fin and a brass plate. When current is applied to the PTC element, it generates heat to warm the air that passes through the unit.

   

   Text in Illustration

   *1	PTC Element	*2	Aluminum Fin
   *3	Brass Plate	-	-

Mode Position and Door Operation

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

• *: Cold area specification models

Air Outlets and Airflow Volume

Indication	Mode	A	B	C	D
		Center	Side	Foot	Defroster
	FACE			-	-
	BI-LEVEL				-
	FOOT	-
	FOOT/DEF	-
	DEF	-		-

Compressor Operation

1. The electric inverter compressor (compressor with motor assembly) performs suction, compression and discharge of refrigerant gas as described in the table below.

   Stroke	Operation
   Suction	As the capacity of the compression chamber, which is created between the rotating scroll and the fixed scroll, increases in accordance with the revolution of the rotating scroll, refrigerant gas is drawn in from the intake port.
   Compression	From the state at which the suction process has been completed, as the revolution of the rotating scroll advances further, the capacity of the compression chamber decreases gradually. Consequently, the refrigerant gas that has been drawn in becomes compressed gradually and is sent to the center of the fixed scroll. The compression of the refrigerant gas is completed when the rotating scroll completes approximately 2 revolutions.
   Discharge	When the compression of the refrigerant gas is completed and the refrigerant pressure becomes high, the refrigerant gas discharges through the discharge port located in the center of the fixed scroll by pushing the discharge valve.

   

   Text in Illustration

   *1	Discharge Port	*2	Rotating Scroll
   *3	Intake Port	*4	Fixed Scroll
   *a	Suction	*b	Compression
   *c	Discharge	-	-