Nissan Ariya: System Description

• Component Parts. Refrigeration System
• System

Component Parts. Refrigeration System

Component Parts Location

COMPONENT PARTS LOCATION

Built-in A/C unit assembly

Built-in A/C unit assembly

Lower left side in the motor room

COMPONENT PARTS DESCRIPTION

No.	Location	DESCRIPTION
	Condenser	Cools the high-temperature high-pressure refrigerant discharged from the compressor to charge it to liquid refrigerant when cooling is operating. Causes fine mist liquid refrigerant to evaporate and changing it into gas refrigerant, by using the air blown from the cooling fan when heating is operating.
	Accumulator	For preventing refrigerant in flow to the compressor, separates gas refrigerant and liquid refrigerant and collects the liquid refrigerant temporarily.
	Refrigerant pressure sensor	Refer to Refrigerant Pressure Sensor.
	Inner condenser	Cools the high-temperature high-pressure refrigerant discharged from the compressor to charge in to liquid refrigerant. The air blown from the blower motor is heated by the condensation heat.
	Evaporator	The misty liquid refrigerant causes evaporation and turns into gas by the air blown from blower motor. Cool the air by vaporization heat at this time.
	Electric compressor	Performs the intake, compression, and discharge of refrigerant, and circulates the refrigerant in the cooler cycle.

Electric Compressor

• An electric scroll compressor is used.

  

• A 3-phase output inverter with IGBT^Note is used.

  NOTE:

  IGBT (Insulated Gate Bipolar Transistor) is a transistor which is suitable for high voltages and large currents and which can control large electrical power using a small gate voltage.

• The inverter and motor portion.

  Refer to Electric Compressor.

• The structure integrates the inverter, compressor, and motor, allowing compressor to operate at any speed.

• A scroll-type compressor is used. The motor drive force is used to rotate the moveable scroll and perform refrigerant intake, compression, and discharge.

  

Condenser

A parallel-flow condenser.

Accumulator

A accumulator compatible with HFO-1234yf refrigerant is used.

Evaporator Pressure Regulator

By controlling the evaporation pressure (temperature), freezing of the evaporator is prevented.

Battery Coolant Chiller

A heat exchanger for cooling high-voltage battery was adopted.

Refrigerant and Compressor Oil

• The refrigerant is HFO-1234yf, which contains no chlorine (Cl), a substance which damages the ozone layer.

• The compressor oil is ND-OIL11, an ester oil with high insulation performance, designed especially for electric compressors.

CAUTION:

• The special electric compressor oil has different properties from the conventional HFO-1234yf, compressor oil (PAG oil) and CFC-12 compressor oil (mineral oil). Be sure not to mix these oil types with the compressor oil, as doing so may cause electric leakage.

NOTE:

• HFC: HydroFluoroCarbon

• CFC: ChloroFluoroCarbon

A/C Unit

This system utilizes an A/C unit that combines blower unit, heater unit, and cooling unit.

Evaporator

A thin laminate pipeless evaporator is used.

Inner Condenser

A paralel-flow inner condenser.

Intake & Distribution Box

This system utilizes an intake and distribution box that combines intake box and distribution box.

High Voltage Warning Label

The label is stuck on the controller part of PTC heater.

: Application direction of the label

System

System Diagram

COOLER MODE

	Electric compressor		Pressure relief valve		Inner condenser
	Electric expansion valve (heater)		Condenser		Check valve
	Electric expansion valve (cooler)		Evaporator		Refrigerant pressure sensor
	Evaporator pressure regulator		Accumulator		High pressure refrigerant channel switching valve
	Low pressure refrigerant channel switching valve		Expansion valve (battery chiller)		Battery coolant chiller
	Blower motor		High-pressure gas		Gas-liquid two phase in high pressure
	High-pressure liquid		Gas-liquid two phase in low pressure		Low-pressure gas
	Refrigerant flow		Wind flow

HEATER MODE

	Electric compressor		Pressure relief valve		Inner condenser
	Electric expansion valve (heater)		Condenser		Check valve
	Electric expansion valve (cooler)		Evaporator		Refrigerant pressure sensor
	Evaporator pressure regulator		Accumulator		High pressure refrigerant channel switching valve
	Low pressure refrigerant channel switching valve		Expansion valve (battery chiller)		Battery coolant chiller
	Blower motor		High-pressure gas		Gas-liquid two phase in high pressure
	High-pressure liquid		Gas-liquid two phase in low pressure		Low-pressure gas
	Refrigerant flow		Wind flow

SERIES OPERATION MODE OF DEHUMIDIFYING AND HEATING

	Electric compressor		Pressure relief valve		Inner condenser
	Electric expansion valve (heater)		Condenser		Check valve
	Electric expansion valve (cooler)		Evaporator		Refrigerant pressure sensor
	Evaporator pressure regulator		Accumulator		High pressure refrigerant channel switching valve
	Low pressure refrigerant channel switching valve		Expansion valve (battery chiller)		Battery coolant chiller
	Blower motor		High-pressure gas		Gas-liquid two phase in high pressure
	High-pressure liquid		Gas-liquid two phase in low pressure		Low-pressure gas
	Refrigerant flow		Wind flow

PARALLEL OPERATION MODE OF DEHUMIDIFYING AND HEATING

	Electric compressor		Pressure relief valve		Inner condenser
	Electric expansion valve (heater)		Condenser		Check valve
	Electric expansion valve (cooler)		Evaporator		Refrigerant pressure sensor
	Evaporator pressure regulator		Accumulator		High pressure refrigerant channel switching valve
	Low pressure refrigerant channel switching valve		Expansion valve (battery chiller)		Battery coolant chiller
	Blower motor		High-pressure gas		Gas-liquid two phase in high pressure
	High-pressure liquid		Gas-liquid two phase in low pressure		Low-pressure gas
	Refrigerant flow		Wind flow

COOLING + HIGH VOLTAGE BATTERY COOLING MODE

	Electric compressor		Pressure relief valve		Inner condenser
	Electric expansion valve (heater)		Condenser		Check valve
	Electric expansion valve (cooler)		Evaporator		Refrigerant pressure sensor
	Evaporator pressure regulator		Accumulator		High pressure refrigerant channel switching valve
	Low pressure refrigerant channel switching valve		Expansion valve (battery chiller)		Battery coolant chiller
	Blower motor		High-pressure gas		Gas-liquid two phase in high pressure
	High-pressure liquid		Gas-liquid two phase in low pressure		Low-pressure gas
	Refrigerant flow		Wind flow

DEICE MODE

	Electric compressor		Pressure relief valve		Inner condenser
	Electric expansion valve (heater)		Condenser		Check valve
	Electric expansion valve (cooler)		Evaporator		Refrigerant pressure sensor
	Evaporator pressure regulator		Accumulator		High pressure refrigerant channel switching valve
	Low pressure refrigerant channel switching valve		Expansion valve (battery chiller)		Battery coolant chiller
	Blower motor		High-pressure gas		High-pressure liquid
	Gas-liquid two phase in low pressure		Low-pressure gas		Refrigerant flow

System Description

REFRIGERANT CYCLE

Refrigerant Flow

• The cooler mode path of refrigerant flow is through the electric compressor, inner condenser, electric expansion valve (heater), condenser, electric expansion valve (cooler), evaporator, evaporator pressure regulator, accumulator, and then it returns to the electric compressor.

• The heater mode path of refrigerant flow is through the electric compressor, inner condenser, electric expansion valve (heater), condenser, low pressure refrigerant channel switching valve, accumulator, and then it returns to the electric compressor.

• The series operation mode of dehumidifying and heating path of refrigerant flow is through the electric compressor, inner condenser, electric expansion valve (heater), condenser, electric expansion valve (cooler), evaporator, evaporator pressure regulator, accumulator, and then it returns to the electric compressor.

• The flow of refrigerant during parallel operation mode of dehumidifying and heating flows through two paths at the same time. One goes through electric compressor, inner condenser, electric expansion valve (heater), condenser, low pressure refrigerant channel switching valve, accumulator, and then it returns to electric compressor. Other goes through electric compressor, inner condenser, high pressure refrigerant channel switching valve, electric expansion valve (cooler), evaporator, evaporator pressure regulator, accumulator, and then it returns electric compressor.

• The flow of refrigerant during cooling + high voltage battery cooling mode flows through two paths at the same time. One goes through electric compressor, inner condenser, electric expansion valve (heater), condenser, expansion valve (battery chiller), battery coolant chiller, accumulator, and then it returns to electric compressor. Other goes through electric compressor, inner condenser, electric expansion valve (heater), condenser, electric expansion valve (cooler), evaporator, evaporator pressure regulator, accumulator, and then it returns to electric compressor.

• The deice mode path of refrigerant flow is through the electric compressor, inner condenser, electric expansion valve (heater), condenser, low pressure refrigerant channel switching valve, accumulator, and then it returns to the electric compressor.

Evaporator Cryoprotective Protection Control

Refer to Electric Compressor Control.

REFRIGERANT SYSTEM PROTECTION

Refrigerant Pressure Sensor

• The refrigerant system is protected from significant high pressure and low pressure by the refrigerant pressure sensor that is installed at the condenser outlet.

• The refrigerant pressure sensor outputs a signal to the VCM.

• If the A/C auto amp., judges that there is a malfunction (the conditions shown below) in the cooler cycle based on the refrigerant pressure sensor detection value sent from VCM via CAN communications, it stops operation of the electric compressor.

Pressure Relief Valve

• The refrigerant system is protected from significant high pressure by the pressure relief valve that is installed in the electric compressor.

• If the pressure in the cooler cycle is excessively increased [3,430 kPa (34.3 bar, 35 kg/cm², 497.4 psi) or more], the pressure relief valve opens, releasing refrigerant into the atmosphere.

Preparation. PreparationBasic Inspection