AIRFLOW TEMPERATURE CONTROL OPERATION[MZ-CD 1.6 (Y6)]

• The climate control unit calculates the air mix actuator opening angle characteristic for the given ambient temperature based on the set temperature, sunlight intensity, and airflow mode. The air mix actuator opening angle characteristic decreases as the sunlight intensity increases.

• The opening angle characteristic of the air mix actuator and the current ambient temperature are compared and the basic opening angle for the air mix actuator is determined according to the A/C compressor control status. The opening angle must maintain the target temperature (calculated control value T1) in the cabin against changes in external factors such as sunlight intensity and ambient temperature.

• If there is a difference between the target temperature (calculated control value T1) and current cabin temperature, the basic opening angle of the air mix actuator is corrected so that the cabin temperature rapidly reaches the target temperature.

• Calculated control value T1 is the target temperature in the cabin as set by the climate control unit based on differences among the set temperature, temperatures input from the sensors, and sunlight intensity. Calculated control value T1 is calculated according to the changes in the set temperature and temperatures input from the sensors.

1	Low sunlight intensity
2	High sunlight intensity
3	Air mix actuator opening angle characteristic (A/C off mode)
4	Air mix actuator opening angle characteristic (A/C on mode)
5	Fully open (MAX HOT)
6	Fully closed (MAX COLD)
7	Air mix actuator opening angle
8	Low
9	High
10	Ambient temperature

1. The climate control unit determines the PTC heater ON/OFF, and sends the signal to the PJB.

2. The PJB calculates the PTC operation ratio, operates the PTC heater, and sends the operation ratio to the climate control unit.

3. The climate control unit corrects the air mix actuator opening angle in accordance with the PTC operation ratio.

1	PTC heater on/off signal
2	PTC operation ratio received
3	Airflow temperature control
4	Air mix actuator
5	Climate control unit
6	Ambient temperature sensor, ECT sensor
7	PTC heater control (PTC operation ratio calculation)
8	PTC heater
9	PTC operation ratio control specification
10	Calculates PTC operation ratio from ambient air
11	Calculates PTC operation ratio from engine coolant temperature
12	Selects lower of A, B
13	PTC operation ratio from ambient air
14	PTC operation ratio from engine coolant temperature
15	PTC operation ratio
16	Ambient temperature
17	Engine coolant temperature

• When the air intake mode is switched from FRESH to REC when the A/C is off, a correction is added to the air mix actuator opening angle to prevent a rise in airflow temperature. In addition, this correction delays the air mix actuator operation to prevent a sudden drop in airflow temperature.

1	Air intake door
2	Fresh
3	Recirculate
4	HOT
5	COLD
6	Air mix actuator opening angle correction amount
7	Time

• When the A/C compressor control is switched from A/C ON mode to OFF mode, the opening angle of the air mix actuator is switched from the A/C ON mode opening angle to the A/C OFF mode opening angle to prevent a rise in airflow temperature. In addition, this correction delays the air mix actuator operation to prevent a sudden drop in airflow temperature. However, the operation is not delayed when the evaporator temperature is 15 °C {59 °F} or more.

1	A/C compressor control
2	A/C on mode
3	A/C off mode
4	HOT
5	COLD
6	Air mix actuator opening angle correction amount
7	Time

• When the engine is cold, the air mix door is fully open, and the blower fan is operating, the PTC operates for supplementary heating at the heater core. However, this control is not performed when the ambient temperature is 20 °C {68 °F} or more, or the engine coolant temperature is 70 °C {158 °F} or more.

• When the PTC heater switches from OFF mode to ON, the climate control unit corrects the air mix actuator to the COLD side according to the PTC operation ratio sent from the PJB to prevent an excessive rise in airflow temperature. In addition, this correction delays the air mix actuator operation to prevent sudden rises/drops in airflow temperature during ON/OFF switching of the PTC heater.

• When the temperature is set to 29.0, the air mix actuator opening angle is fixed at fully open and when set to 15.0, it is fixed at fully closed.

• The PTC heater operates when the temperature is set at 29.0 with the fan switch on. However, the PTC heater dose not operate when the ambient temperature is 20 °C {68 °F} or more, or the engine coolant temperature is 70 °C {158 °F} or more.

• After the engine is started in winter, the air mix actuator opening angle is corrected so that it is adjusted to the HOT side to prevent discomfort caused by cold air blown from the vent. However, the engine coolant temperature correction is not performed when the ambient temperature is 10 °C {50 °F} or more.

1	PTC heater on
2	PTC heater off
3	Air mix actuator opening angle