With 7 Inch Display
AUTOMATIC AIR CONDITIONER SYSTEM
System Description
OUTLINE
- Automatic air conditioner system is controlled by each function of A/C auto amp., ECM and IPDM E/R.
Control by A/C auto amp.
- Air outlet control
- Temperature control
- Air inlet control
- Air flow control
- Compressor control
- Door motor control (LCU communication control)
Control by ECM
- Cooling fan control. (Refer to System Description.)
- Air conditioning cut control. (Refer to System Description.)
Control by IPDM E/R
- Relay control. (Refer to System Description.)
- Cooling fan control. (Refer to System Description.)
- Controller (preset switch) transmits the commands for air conditioner system operation to AV control unit via communication line, then AV control unit transmits the commands to A/C auto amp. via CAN communication.
A/C auto amp. transmits each indication information to AV control unit via CAN communication. AV control unit displays each indication information that is received.
OPERATION AND DISPLAY
A/C Display
- Air conditioner system state is indicated on the display.
- When "Status" on multifunction switch is pressed while air conditioner system is in the ON position, the display changes to state indication display of air conditioner system. When air conditioner is operated while navigation system or audio system is displayed, air conditioner system state is indicated in the lower portion of display for several seconds.
- When MODE switch is pressed while air conditioner system is in the OFF position, state indication display is indicated for several seconds.
Controller (Preset Switch)
Switch Operation
AIR OUTLET CONTROL
- While air outlet is in automatic control, A/C auto amp. selects the mode door position depending on a target air mix door angle and outlet air temperature calculated from sunload.
- If ambient temperature is excessively low, D/F is selected to prevent windshield fogging when air outlet is set to FOOT.
TEMPERATURE CONTROL
- When ignition switch is in the ON position, A/C auto amp. always automatically controls temperature regardless of air conditioner operational state.
- A/C auto amp. calculates the target air mix door opening angle depending on set temperature, in-vehicle temperature, ambient temperature, and sunload.
- Air mix door is controlled depending on the comparison of current air mix door opening angle and target air mix door opening angle.
- Regardless of in-vehicle temperature, ambient temperature, and sunload, air mix door is fixed at the fully cold position when set temperature is 18.0 °C (60 °F), and at the fully hot position when set temperature is 32.0 °C (90 °F).
AIR INLET FUNCTION
While air inlet is in automatic control, A/C auto amp. selects air inlet
(fresh air intake, 20% fresh air intake, or recirculation) depending on set temperature, in-vehicle temperature, and ambient temperature.
AIR FLOW CONTROL
Description
- A/C auto amp. changes duty ratio of blower motor drive signal and controls air flow continuously. When air flow is increased, duty ratio of blower motor drive signal gradually increases to prevent a sudden increase in air flow.
- In addition to manual control and automatic control, air flow control is compose of starting fan speed control, low coolant temperature starting control, high in-vehicle temperature starting control, fan speed control at door motor operation, and fan speed control at voice recognition.
Automatic Air Flow Control
- A/C auto amp. decides target air flow depending on target air mix door opening angle.
- A/C auto amp. changes duty ratio of blower motor drive signal and controls air flow continuously so that air flow matches to target air flow.
- When air outlet is VENT or B/L, the minimum air flow is changed depending on sunload.
Starting Fan Speed Control
When blower motor is activated, A/C auto amp. gradually increases duty ratio of blower fan drive signal to prevent a sudden increase in discharge air flow. (It takes approximately 8 seconds for air flow to reach HI from LOW)
Low Coolant Temperature Starting Control
If the engine coolant temperature is 56 °C (133 °F) or less, to prevent a cold discharged air flow, A/C auto amp. suspends blower motor activation for the maximum 150 seconds depending on target air mix door opening angle. After this, blower fan drive signal is increased gradually, and blower motor is activated.
High In-vehicle Temperature Starting Control
When evaporator temperature is high [intake air temperature sensor value is 35 °C (95 °F) or more], to prevent a hot discharged air flow, A/C auto amp. suspends blower motor activation for approximately 3 seconds so that evaporator is cooled by refrigerant.
Fan speed Control at Door Motor Operation
When mode door motor is activated while air flow is more than the specified value, A/C auto amp. reduces temporarily fan speed so that mode door moves smoothly.
Fan speed Control at Voice Recognition
When the voice control (voice command) switch is operated during air flow automatic control, A/C auto amp. decreases the air flow of the blower motor once and controls the air flow so as not to disturb the voice recognition function. This control continues while voice recognition function is operating.
COMPRESSOR CONTROL
Description
- When the compressor activation condition is satisfied while blower motor is activated, A/C auto amp. transmits A/C ON signal and blower fan ON signal to ECM via CAN communication.
- ECM judges that the compressor can be activated depending on each sensors state (refrigerant pressure sensor signal, throttle opening angle sensor signal, and others). And transmits air conditioner relay control signal to IPDM E/R via CAN communication.
- IPDM E/R turns air conditioner relay ON and activates the compressor depending on request from ECM.
Compressor Protection Control at Pressure Malfunction
When high-pressure side value that is detected by refrigerant pressure sensor is as per the following state, ECM requests IPDM E/R to turn air conditioner relay OFF and stops the compressor.
- 3.12 MPa (31.8 kg/cm2.G) or more (When the engine speed is less than 1,500 rpm)
- 2.74 MPa (27.9 kg/cm2.G) or more (When the engine speed is 1,500 rpm or more)
- 0.14 MPa (1.4 kg/cm2.G) or less
Compressor Oil Circulation Control
When the engine starts while the engine coolant temperature is 56 °C (133 °F) or less, ECM activates the compressor for approximately 6 seconds and circulates the compressor lubricant once.
Low Temperature Protection Control
When intake air temperature sensor detects that air temperature after passing through evaporator is -5 °C (23 °F) or less, A/C auto amp. requests ECM to turn the compressor OFF, and stops the compressor.
When the air temperature returns to 1 °C (34 °F) or more, the compressor is activated.
Operating Rate Control
When set temperature is other than fully cold or air outlet is "VENT", "B/L" or "FOOT" A/C auto amp. controls the compressor activation depending on ambient temperature.
Air Conditioner Cut Control
When the engine is running in excessively high load condition, ECM requests IPDM E/R to turn air conditioner relay OFF, and stops the compressor. Refer to System Description for details.
DOOR MOTOR CONTROL
- LCU (Local Control Unit) is built in to each door motor. And detects door position by PBR (Potentio Balance Resistor).
- A/C auto amp. communicates with each LCU via communication line. And receives each door position signal from each LCU.
- Each LCU controls each door to the appropriate position depending on the control signal from A/C auto amp. when the door movement is complete, transmits the signal of door movement completion to A/C auto amp.
FAIL-SAFE CONTROL
When a communication malfunction occurs between A/C auto amp. and AV control unit or preset switch for 30 seconds or more, A/C auto amp. automatically controls air outlet and fan speed, fixes air inlet to fresh air intake, maintains set temperature data before the communication malfunction, and activates the compressor.
Even if the condition before the communication error occurs is A/C OFF, A/C auto amp. turns the compressor
ON with following conditions.
SWITCHES AND THEIR CONTROL FUNCTIONS
AIR DISTRIBUTION
