System Description

BLOWER MOTOR CONTROL SYSTEM


System Description


SYSTEM OPERATION
- For air flow, the manual selection (1-7 speed) with the fan control dial has priority.
- If the AUTO switch is pressed or if the DEF switch is pressed while in the OFF condition, it changes to the automatic control by unified meter and A/C amp.
- When increasing the air flow, it changes the duty ratio of blower fan motor control signal to prevent the air flow from suddenly increasing.
- There are the following types of air flow control: starting air flow control, starting air flow control at low coolant temperature, starting air flow control at high interior air temperature, air flow control at actuator operation, and air flow control at voice recognition in addition to manual control, normal automatic air flow control.

AIR FLOW CONTROL

Automatic Air Flow Control
- When the target temperature is set by the temperature control dial of preset switch, the unified meter and A/C amp. performs the calculation and decides the target air flow according to the signal from each sensor.
- The unified meter and A/C amp. changes the duty ratio of blower motor control signal and controls the air flow continuously so that the air flow becomes the target air flow.





- The minimum air flow will change according to the sunload when the air discharge outlet is VENT or B/L.

Starting Air Flow Control
- When starting the automatic control of air flow, the system gradually increases the duty ratio of the blower motor control signal to prevent too much air from blowing.
- The time period from when the air flow changes from LOW to HI is approximately 8 seconds.
- It becomes the starting air flow control at low coolant temperature according to the calculation result of auto amp and engine coolant temperature [approximately 56�C (133�F) or less] during the automatic air flow control.
- Do not perform the starting air flow control when the air discharge outlet is set to DEF.

Low Coolant Temperature Starting Control
- It stops the blower motor for approximately 150 seconds at the maximum according to the target air mix door position based on the calculation result of unified meter and A/C amp. and engine coolant temperature
[approximately 56�C (133�F) or less] when starting the automatic air flow control. Then, it increases the duty ratios gently so as not to blow cold air underfoot.
- Change the increase rate of the duty ratio to the normal automatic air flow control when the engine coolant temperature is approximately 56�C (133�F) or more in the starting air flow control at low coolant temperature.

High In-vehicle Temperature Starting Control
Turn the blower motor to OFF while the evaporator is cooled by the refrigerant (approximately 3 seconds) to prevent the hot air from blowing out when the evaporator temperature is high [approximately 35�C (95�F) or more of intake sensor detection temperature] at starting the blower motor.

Fan Speed Control at Door Motor Operation
When the mode door motor operated at the air flow automatic control, it decreases the air flow of the blower motor once and controls it so that the mode door motor moves smoothly.

Fan Speed Control at Voice Recognition (With Navigation)
When the voice command switch is operated at the air flow automatic control, it decreases the air flow of the blower motor once and controls it so as not to disturb the voice recognition function. In addition, this control continues while the voice recognition function is operating.

Fan Speed Control at roof open
- Unified meter & A/C amp. receives roof status signal from retractable hard top control unit via CAN communication and detects the roof status.
- When roof is in the open status, air flow volume correction and outlet change are automatically performed according to ambient temperature and vehicle speed.
- When ambient temperature is lower than the specified value, temperature felt (especially in the upper half of passenger body) lowers due to wind resulting from driving speed. Therefore, unified meter & A/C amp. corrects air flow volume to increase and change outlet to B/L according to increase in vehicle speed, so that heating intensifies.
- When ambient temperature is higher than the specified value, temperature felt (especially in the upper half of passenger body) increases due to direct sunlight because there is no wind resulting from driving speed when vehicle is stopped. Therefore, unified meter & A/C amp. corrects air flow volume increase, so that cooling intensifies.
Air flow volume correction is decreased when vehicle speed is increased and there is wind resulting from driving speed.