AIR CONDITIONING SYSTEM

GENERAL

The air conditioning system has the following controls.

Control	Outline
Neural Network Control	This control is capable of performing complex control by artificially simulating the information processing method of the nervous system of living organisms in order to establish a complex input/output relationship similar to that of a human brain.
Outlet Air Temperature Control	Based on the temperature set by the temperature control dial, neural network control calculates outlet air temperature based on input signals from various sensors.
Dual Control*1	The temperature settings for the driver and front passenger are controlled independently in order to provide separate vehicle interior temperatures for the right and left sides of the vehicle. Thus, air conditioning that accommodates the occupants' preferences has been realized.
Blower Control	Controls the blower motor in accordance with the airflow volume that has been calculated by neural network control based on input signals from various sensors.
Air Outlet Control	Automatically switches the air outlets in accordance with the outlet mode that has been calculated by neural network control.
Air Outlet Control	In accordance with the engine coolant temperature, ambient air temperature, amount of sunlight, required blower, outlet temperature and vehicle speed conditions, this control automatically switches the blower outlet to foot/defroster mode to prevent the windows from becoming fogged up when the ambient air temperature is low.
Air Inlet Control	Automatically controls the air inlet control damper to help achieve the calculated outlet air temperature that is required.
Air Inlet Control	Drives the air inlet control servo motor according to the operation of the air inlet control switch and moves the dampers to the fresh or recirculation position.
Electric Inverter Compressor Control	Based on the target evaporator temperature (which is calculated through signals from the cooler (room temp. sensor) thermistor, thermistor assembly and automatic light control sensor) and the actual evaporator temperature that is detected by the No. 1 cooler thermistor the air conditioning amplifier assembly calculates the target compressor speed and controls the compressor speed.
	The air conditioning amplifier assembly calculates the target evaporator temperature (based on signals from the cooler (room temp. sensor) thermistor, thermistor assembly, automatic light control sensor and No. 1 cooler thermistor) and controls the compressor speed to an extent that will not inhibit proper cooling performance and defogging performance.
	Turns the A/C on automatically when the AUTO button is pressed when the blower is on and the A/C is off.
	Decreases the compressor speed in order to ensure quietness when the vehicle is stopped or the engine is off.
Defroster Control	Defroster control logic is used to improve defroster performance.
PTC Heater Control*2	When the hybrid system is operating (READY), and the blower motor with fan sub-assembly is turned on, the air conditioning amplifier assembly turns on the quick heater assembly if the conditions listed below are met. Engine coolant temperature is below specified temperature. Outside temperature is below specified temperature. Tentative air mix damper opening angle is above the specified value (MAX HOT).
S-FLOW Control	When the S-FLOW switch is turned on, the air outlets operate in a front seat control mode.
Rear Defogger Control	Refer to Rear Defogger System. Click here
ECO Mode Control	When the pattern select switch assembly (DRIVE MODE switch) or air conditioning control assembly (ECO HEAT/COOL switch) is turned on, the air conditioning amplifier assembly limits the air conditioning system performance.
Blower Customize*1	During automatic air conditioning operation, the air volume can be adjusted in 3 levels using the air conditioning control assembly (AUTO FAST/ECO switch): NORMAL → ECO (small air volume) → FAST (large air volume).
Diagnosis	A Diagnostic Trouble Code (DTC) is stored in memory when the air conditioning amplifier assembly detects a problem with the air conditioning system.

*1: for Dual Type
*2: w/ PTC Heater

NEURAL NETWORK CONTROL

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

MODE POSITION AND DAMPER OPERATION

Mode Position and Damper Operation

Figure 1. for Dual Type

*1	Driver Side Air Mix Control Damper	*2	Front Passenger Side Air Mix Control Damper
*3	Driver Side Side Defroster	*4	Front Defroster
*5	Front Passenger Side Side Defroster	*6	Air Inlet Control Damper (Lower Side)
*7	Air Inlet Control Damper (Upper Side)	*8	Clean Air Filter
*9	Blower with Fan Motor Sub-assembly	*10	No. 1 Cooler Evaporator Sub-assembly
*11	Air Mix Control Damper	*12	Heater Radiator Unit Sub-assembly
*13	PTC Heater (Quick Heater Assembly)	*14	Mode Switching Damper
*15	Driver Side Footwell Register	*16	Front Passenger Side Footwell Register
*17	Driver Side Side Register	*18	Center Register
*19	Front Passenger Side Side Register	*20	Driver Side Rear Footwell Register
*21	Front Passenger Side Rear Footwell Register	-	-
*a	Illustration Image View from [A]	*b	[A] View
*c	Recirculated Air	*d	Fresh Air

Functions of Main Dampers
Control Damper	Operation Position	Damper Position	Operation
Air Inlet Control Damper	FRESH	A1, B1	Allows fresh air to enter.
Air Inlet Control Damper	RECIRCULATION	A2, B2	Causes internal air to recirculate.
Air Mix Control Damper	Temperature Setting: 16°C (61°F) to 30°C (86°F)	C1 - C2	Varies the front passenger side mixture ratio of the fresh air and the recirculation air in order to regulate the temperature continuously from HI to LO.
Air Mix Control Damper	Temperature Setting: 16°C (61°F) to 30°C (86°F)	D2 - D1	Varies the driver side mixture ratio of the fresh air and the recirculation air in order to regulate the temperature continuously from HI to LO.
Air Outlet Control Damper	DEF	F, H, K	Defrosts the windshield through the center defroster, side defrosters and side registers.
	FOOT/DEF	F, H, J to K	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.
	FOOT	E, (E to F)*, H, J	Air blows out of the front and rear footwell register ducts and side registers. In addition, air blows out slightly from the center defroster and side defrosters.
	B/L	E, G to I, J to K	Air blows out of the center registers, side registers and front and rear footwell register ducts.
	FACE	E, G, K	Air blows out of the center registers and side registers.

Figure 2. for Single Type

*1	Air Mix Control Damper	*2	Driver Side Side Defroster
*3	Front Defroster	*4	Front Passenger Side Side Defroster
*5	Air Inlet Control Damper (Lower Side)	*6	Air Inlet Control Damper (Upper Side)
*7	Clean Air Filter	*8	Blower with Fan Motor Sub-assembly
*9	No. 1 Cooler Evaporator Sub-assembly	*10	Air Mix Control Damper
*11	Heater Radiator Unit Sub-assembly	*12	Mode Switching Damper
*13	Driver Side Footwell Register	*14	Front Passenger Side Footwell Register
*15	Driver Side Side Register	*16	Center Register
*17	Front Passenger Side Side Register	*18	Driver Side Rear Footwell Register
*19	Front Passenger Side Rear Footwell Register	-	-
*a	Recirculated Air	*b	Fresh Air

Functions of Main Dampers
Control Damper	Operation Position	Damper Position	Operation
Air Inlet Control Damper	FRESH	A1, B1	Allows fresh air to enter.
Air Inlet Control Damper	RECIRCULATION	A2, B2	Causes internal air to recirculate.
Air Mix Control Damper	Temperature Setting: 16°C (61°F) to 30°C (86°F)	C - D	Varies the mixture ratio of the fresh air and the recirculation air in order to regulate the temperature continuously from HI to LO.
Air Outlet Control Damper	DEF	F, H, K	Defrosts the windshield through the center defroster, side defrosters and side registers.
	FOOT/DEF	F, H, J to K	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.
	FOOT	E, (E to F)*, H, J	Air blows out of the front and rear footwell register ducts and side registers. In addition, air blows out slightly from the center defroster and side defrosters.
	B/L	E, G to I, J to K	Air blows out of the center registers, side registers and front and rear footwell register ducts.
	FACE	E, G, K	Air blows out of the center registers and side registers.

AIR OUTLETS AND AIRFLOW VOLUME

The size of each circle ○ indicates the ratio of airflow volume.

Air Outlets and Airflow Volume (for All Seat Control Modes).

Mode	FACE		FOOT		DEF
	Center	Side	Front	Rear	Center	Side
	A	B	C	D	E	F
FACE
B/L
FOOT
FOOT/DEF
DEF

Air Outlet and Airflow Volume (for Front Seat Control Modes).

*: Airflow is stopped when the front passenger seat is not occupied.

Mode	FACE		FOOT		DEF
	Center	Side	Front	Rear	Center	Side
	A	B	C	D	E	F
FACE
B/L
FOOT
FOOT/DEF
DEF

PARKING FRESH CONTROL (w/ Rear Seat Belt Warning)

When 60 seconds have elapsed since the power switch has been turned off, the air conditioning amplifier assembly uses control logic which automatically changes the air inlet to FRESH mode to purge undesired odors from the air conditioning unit.

This logic will therefore reduce undesired odors upon starting the air conditioning system.

COMPRESSOR WITH MOTOR ASSEMBLY

General

Tech Tips

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 (ND-OIL 11) with a high level of insulation performance. Therefore, never use a compressor oil other than ND-OIL 11 type compressor oil or equivalent.
1. Along with the use of the hybrid system 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 an ordinary scroll compressor, except that it is driven by an electric motor.
2. The Air Conditioning (A/C) inverter is integrated into the compressor with motor assembly.
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 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 uses high-voltage alternating current. If a short or open circuit occurs in the compressor, the hybrid vehicle control ECU will cut off the A/C inverter circuit in order to stop the power supply to the compressor motor.
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 temp. sensor) thermistor, thermistor assembly, and automatic light control sensor) and the actual evaporator temperature detected by the 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 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 assembly calculates the target evaporator temperature (based on signals from the cooler (room temp. sensor) thermistor, thermistor assembly, automatic light control sensor and No. 1 cooler thermistor) and controls the compressor speed to an extent that will not inhibit proper cooling performance and defogging performance. As a result, comfort and low fuel consumption can be realized.

NO. 1 COOLER THERMISTOR

The No. 1 cooler thermistor detects the temperature of the cool air immediately after the evaporator in the form of resistance changes, and outputs it to the air conditioning amplifier assembly.

BLOWER MOTOR WITH FAN SUB-ASSEMBLY

The blower motor has a built-in blower controller, and is controlled using duty control performed by the air conditioning amplifier assembly.

BUS CONNECTOR (AIR CONDITIONING HARNESS ASSEMBLY)

Bus connectors are used in the wire harness that connects the servo motors to the air conditioning amplifier assembly.

*A	for LHD	*B	for RHD
*a	Example	*b	Bus Connector (to No. 1 Air Conditioning Radiator Damper Servo Sub-assembly)
*c	Bus Connector (to No. 2 Air Conditioning Radiator Damper Servo Sub-assembly)	*d	Bus Connector (to No. 3 Air Conditioning Radiator Damper Servo Sub-assembly)
*e	Bus Connector (to No. 1 Blower Damper Servo Sub-assembly)	*f	to Air Conditioning Amplifier Assembly
*g	to No. 1 Cooler Thermistor	-	-

Each bus connector has a built-in communication/driver IC which communicates with the air conditioning amplifier assembly, 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.

SERVO MOTOR

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

QUICK HEATER ASSEMBLY (w/ PTC Heater)

General

The quick heater assembly is located above the heater core in the air conditioning radiator assembly.

The quick heater assembly consists of a PTC element, aluminum fins, and brass plates. When current is applied to the PTC element, it generates heat to warm the air that passes through the unit.

*1	Quick Heater Assembly	*2	Brass Plate
*3	PTC Element	*4	Aluminum Fin

Quick Heater Assembly Operating Conditions
1. The quick heater assembly is turned on and off by the air conditioning amplifier assembly in accordance with the engine coolant temperature, ambient temperature, temperature setting, and electrical load (generator power ratio).

AIR CONDITIONING THERMISTOR ASSEMBLY

The air conditioning thermistor assembly detects the amount of raindrops on the windshield glass, the temperature of the windshield glass, and the temperature and humidity around the windshield glass and sends signals to the air conditioning amplifier assembly.

COOLER (ROOM TEMP. SENSOR) THERMISTOR

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

THERMISTOR ASSEMBLY

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

AUTOMATIC LIGHT CONTROL SENSOR

The automatic light control 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 and outputs these sunlight strength signals to the air conditioning amplifier assembly.

AIR CONDITIONER PRESSURE SENSOR

The air conditioner pressure sensor detects the refrigerant pressure and outputs it to the air conditioning amplifier assembly in the form of voltage changes.

AIR CONDITIONING SYSTEM SYSTEM DESCRIPTION