System Description

The air conditioning system has the following controls:

1. Mode Position and Damper Operation
   Fig 1: Identifying Front Defroster Operation Diagram

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002
   FUNCTIONS OF MAIN DAMPERS
   
   

   Control Damper	Operation Position	Damper Position	Operation
   Air Inlet Control Damper	FRESH	A	Brings in fresh air.
   	RECIRC	B	Recirculates internal air.
   Air Mix Control Damper	MAX COLD to MAX HOT Temperature Setting 16°C (61°F) to 30°C (86°F)	C - D - E	Varies the mixture ratio of the fresh air and the recirculation air in order to regulate the temperature continuously from HOT to COLD.
   Mode Control Damper	DEF Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	H, K	Defrosts the windshield through the front defroster and side register.
   	FOOT/DEF Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	H, J	Defrosts the windshield through the front defroster and side register, while air is also blown out from the front footwell register duct and rear foot well register duct*2.
   	FOOT Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	H, I	Air blows out of the footwell register duct, rear footwell register duct*2, and side register. In addition, air blows out slightly from the front defroster.
   	BI-LEVEL Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	F, I	Air blows out of the center register, side register, front footwell register duct and rear footwell register duct*2.
   	FACE Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	F, K	Air blows out of the center register and side register.

   *1: w/ PTC Heater Assembly

   *2: for Cold Area

1. Air Outlets and Airflow Volume
   Fig 2: Identifying Air Outlets And Airflow Diagram

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   INDICATION (MODE)	CTR	SIDE	FOOTWELL	DEFROSTER
   	A	B	C	D
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002 FACE	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002 BI-LEVEL	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002 FOOT	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002 FOOT/DEF	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002 DEF	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

1. General
   1. The compressor assembly with pulley is a continuously variable capacity type in which its capacity varies with the cooling load of the air conditioning system.
   2. The compressor consists of the shaft, lug plate, piston, shoe, crank chamber, cylinder, and solenoid control valve.
   3. The solenoid control valve adjusts the suction pressure is provided to enable to be controlled as desired.
   4. A plastic DL (Damper Limiter) type A/C pulley is used.
   5. A rotary valve uses suction to pull refrigerant gas into the cylinder.
      Fig 3: Identifying A/C Compressor Components

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Operation
   1. The crank chamber is connected to the suction passage. A solenoid control valve is provided between the suction passage (low pressure) and the discharge passage (high pressure).
   2. The solenoid control valve duty cycle is controlled in accordance with the signals from the air conditioning amplifier.
      Fig 4: Identifying A/C Compressor Operation Diagram

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   3. When the solenoid control valve closes (solenoid coil is energized), a difference in pressure is created and the crank chamber pressure decreases. Then, the pressure that is applied to the right side of the piston becomes greater than the pressure that is applied to the left side. This compresses the spring and tilts the lug plate. As a result, there is a large piston stroke and the discharge capacity increases.
      Fig 5: Identifying A/C Compressor Operation Diagram

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   4. When the solenoid control valve opens (solenoid coil is not energized), the pressure is equalized. The pressure applied to the left side of the piston becomes equal to the right side. This is performed when the spring elongates and eliminates the tilt of the lug plate. As a result, there is a small piston stroke and the discharge capacity decreases.
      Fig 6: Identifying A/C Compressor Operation Diagram

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. General
   1. The PTC heater is located above the heater core in the air conditioner unit.
   2. The PTC heater consists of a PTC element, aluminum fin, and brass plate. When current is applied to the PTC element, it generates heat to warm the air that passes through the unit.
      Fig 7: Identifying PTC Heater, PTC Element, Aluminum Fin And Brass Plate

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. PTC Heater Operating Conditions
   1. The PTC heater is turned on and off by the air conditioning amplifier in accordance with the coolant temperature, ambient temperature, engine speed, air mix setting, and electrical load (generator power ratio).

      For example, the number of the operating PTC heaters varies by the coolant temperature as in the graph below.

      Fig 8: Identifying PTC Heater Operating Conditions Graph

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

The ambient temperature sensor detects the outside temperature based on changes in the resistance of its built-in thermistor and sends a signal to the A/C amplifier.

The evaporator temperature sensor detects the temperature of the cool air immediately past the evaporator in the form of resistance changes, and outputs it to the A/C amplifier.

The A/C pressure sensor detects the refrigerant pressure and outputs it to the A/C amplifier in the form of voltage changes.

The A/C flow sensor, which is mounted on the compressor assembly with pulley, is used to detect the amount of refrigerant flow. The A/C flow sensor converts the amount of refrigerant flow that is detected to a voltage value to send it to the A/C amplifier. The voltage value sent from the A/C flow sensor changes depending on the amount of refrigerant flow. As the amount of refrigerant flow becomes larger, the voltage becomes lower. As the amount of refrigerant flow becomes smaller, the voltage becomes higher. The A/C amplifier supplies 5 V to the A/C flow sensor and monitors change in the voltage value sent from the A/C flow sensor. The A/C amplifier then sends a signal to the ECM via CAN communication to allow the ECM to control the engine speed while the air conditioning is on.