System Description

The air conditioning system has the following controls:

1. Mode Position and Damper Operation
   Fig 1: Mode Position And Damper Operation Diagram

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Functions of Main Dampers: 

   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	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	H, K	Defrosts the windshield through the front defroster and side register.
   	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 and rear footwell register ducts.
   	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	H, I	Air blows out of the footwell register duct, rear footwell duct, and side register. In addition, air blows out slightly from the front defroster.
   	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	F, I	Air blows out of the center register, side register, and front and rear footwell register ducts.
   	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	F, K	Air blows out of the center register, and side register.

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   Fig 3: Air Outlet and Airflow Volume Chart

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

1. General
   1. An A/C compressor is a continuously variable capacity type in which its capacity varies in accordance with the cooling load of the air conditioner.
   2. This compressor consists of the shaft, lug plate, piston, shoe, crank chamber, cylinder, and solenoid control valve.
   3. The solenoid control valve that adjusts the suction pressure so that the suction pressure can be controlled as desired is provided.
   4. The plastic DL (Damper Limiter) type A/C pulley is used.
      Fig 4: 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 operates under duty cycle control in accordance with the signals from the air conditioning amplifier.
      Fig 5: 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 pressure in the crank chamber 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 of the piston. This compresses the spring and tilts the lug plate. As a result, the piston stroke increases and the discharge capacity increases.
      Fig 6: A/C Compressor Operation Diagram When Solenoid Control Valve Closes

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   4. When the solenoid control valve opens (solenoid coil is not energized), the difference in pressure disappears. Then, the pressure that is applied to the left side of the piston becomes the same as the pressure that is applied to the right side of the piston. Thus, the spring elongates and eliminates the tilt of the lag plate. As a result, there is small piston stroke and the discharge capacity decreases.
      Fig 7: A/C Compressor Operation Diagram When Solenoid Control Valve Opens

      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.