[55] HEATER, AIR CONDITIONER AND VENTILATION - - HEATER AND AIR CONDITIONER SYSTEM | PRINT PAGE / INDEX / PRIOR / NEXT

HEATER AND AIR CONDITIONER SYSTEM
BLOWER ASSEMBLY AND HEATER UNIT The following blower and heater unit has been adopted to increase air volume, reduce noise, improve air conditioner performance, as well as improve the passenger compartment environment. Installation of two-layer blow full air mix heater Incorporation of heater and cooling units Increase in the fresh air intake duct area size of the blower assembly and optimisation of its shape Large-size heater core to improve the heating performance Adopting the thinner evaporator and enlarging its surface area improves the air-conditioning function.
| BLOWER MOTOR CONTROL <VEHICLES WITH THE AUTOMATIC AIR CONDITIONER>
| The linear control with PWM (pulse-width modulation) is adopted to the blower motor speed control. Adopting it prevents the excess rotation of the blower motor and decreases the fuel consumption and noise. The blower pulse controller changes the motor switching time using the pulse signal from A/C-ECU and the motor applied voltage equivalently to control the motor speed linearly.
| TWO-LAYER BLOW FULL AIR MIX HEATER
| In the heater unit, there are two layers of air; one which passes through the heater core, and another which does not pass through the core. One air mixing door is used for temperature control. The two-layer blow full mix heater with low ventilation resistance has increased air volume and has reduced noise.
| MAGNETIC CLUTCH WITH THERMAL FUSE A thermal fuse is installed in the A/C compressor field core. If the compressor fails and locks, the thermal fuse will be blown due to friction heat produced by the drive belt and locked compressor. This deenergises the magnetic clutch and allows the compressor to run freely. Fuse temperature: 184°C
| CONDENSER
| The heat exchange efficiency has been improved with the adoption of a sub-cooling type condenser added with a sub-cooled section. The reduction of line connections by incorporating the condenser and receiver reduces the possibility of refrigerant gas leakage and increases serviceability.
HEATER AND AIR CONDITIONER CONTROL Adoption of the following heater and air conditioner control has improved operation performance and visual observation. Use of rotary control Incorporation of rear window defogger switch with timer Use of a large knob has improved operation performance Improved appearance by incorporating the centre panel Adopting the push button for air circulation change switch improves maneuveability. Enlarging the figures improves the visibility. Green is adopted for the indicator lamp of the air conditioner. A/C-ECU integrated in the control panel controls the system as follows.
| REAR WINDOW DEFOGGER TIMER When the defogger switch is turned to ON with the ignition switch ON, the manual air conditioner automatically turns off after approximately 11 minutes, and the automatic air conditioner turns off after 20 minutes to prevent the battery discharge.
| COMPRESSOR ENERGY CONSERVATION CONTROL
| If the air selection switch is in the outside air mode, information of the lighting switch position and the air thermo sensor sensing temperate is sent to A/C-ECU. Then, sending the signal form the engine-ECU to A/C-ECU executes the energy conservation control of the compressor when evaporator inlet air temperature is from approximately 10°C to approximately 30°C: evaporator outlet temperature is controlled higher than the freezing temperature. If lighting switch is turned ON (tail and headlamp), the temperature is controlled higher than OFF state, presuming of no sun shine. NOTE: Using the lighting switch position checks the insulation.
| COMPRESSOR CUT CONTROL If A/C-ECU detects that the refrigerant amount is less than the specified level or the refrigerant pressure is lower or higher than thresholds, the air temperature (using the air thermo sensor <for the manual air conditioner>, or outside air temperature sensor <for the automatic air conditioner> to measure the refrigerant gas expansion) and the refrigerant pressure (A/C pressure sensor) blink the A/C switch indicator lamp, and forcedly turns off the compressor to prevent the A/C system damage.
| COOLING FUN LOAD CONTROL Depending on the A/C cooling load, the cooling fan speed is controlled continuously with PWM and the exterior noise in the intermediary stage is decreased. Also, the load of the alternator is decreased to improve the fuel economy.
| AIR CIRCULATION AUTO CHANGE CONTROL <VEHICLES WITH THE MANUAL AIR CONDITIONER> If the outside air temperature is high with the A/C switch and the blower switch ON, A/C-ECU changes automatically from the outside air circulation state to the inside air circulation state to cool the room quickly. (With the inside air circulation state, the auto change control will not be made.) After that, only when the air conditioner switch or the blower switch is turned OFF, the change control is made. If the outside/inside air selection switch is operated after the auto change, the switch operation takes the priority.
| OUTSIDE/INSIDE AIR CIRCULATION AUTO CHANGE CONTROL <VEHICLES WITH THE AUTOMATIC AIR CONDITIONER> If the inside air temperature is cooled quickly with the A/C switch and the blower switch ON, A/C-ECU set the inside air circulation mode automatically. Other than during cooling quickly, A/C-ECU gives priority to set the fresh air mode. If the outside/inside air selection switch is operated after the auto change, the switch operation takes the priority.
| DIAGNOSIS CODE <VEHICLES WITH THE AUTOMATIC AIR CONDITIONER>
Code No. | Diagnostic item
--- | ---
11 | Interior temperature sensor system (open circuit)
12 | Interior temperature sensor system (short circuit)
13 | Outside air temperature sensor system (open circuit)
14 | Outside air temperature sensor system (short circuit)
15 | Heater water temperature sensor system (open circuit)
16 | Heater water temperature sensor system (short circuit)
21 | Air thermo sensor system (open circuit)
22 | Air thermo sensor system (short circuit)
31 | Potentiometer system for the air mixing door
32 | Potentiometer system for mode selection damper
41 | Motor drive system for air mixing door
42 | Motor drive system for mode selection damper
| SERVICE DATA TABLE <VEHICLES WITH THE AUTOMATIC AIR CONDITIONER>
Item No. | Check items | Check contents
--- | --- | ---
11 | Interior temperature sensor | Ignition switch: ON | Room temperature is the same as MUT-II displayed temperature.
13 | Outside air temperature sensor | Ignition switch: ON | Outside temperature is the same as MUT-II displayed temperature.
15 | Heater water temperature sensor | Ignition switch: ON | Heater core wall surface temperature is the same as MUT-II displayed temperature.
21 | Air thermo sensor | Ignition switch: ON | Evaporator outlet temperate is the same as MUT-II displayed temperature
25 | Photo sensor | Ignition switch: ON Change the volume of insolation. | The volume of insolation takes inverse proportion with the MUT-II displayed voltage.
31 | Potentiometer for air mixing door | Ignition switch: ON Door position: MAX HOT | Opening angle: approximately 100%
Ignition switch: ON Door position: MAX COOL | Opening angle: approximately 0%
32 | Potentiometer for mode selection damper | Ignition switch: ON Damper position: FACE | Opening angle: approximately 0%
Ignition switch: ON Damper position: FOOT | Opening angle: approximately 60%
Ignition switch: ON Damper position: FOOT/DEF | Opening angle: approximately 80%
Ignition switch: ON Damper position: DEF | Opening angle: approximately 100%
42 | A/C pressure sensor | Ignition switch: ON | Refrigerant pressure is the same as MUT-II displayed pressure.
| ACTUATOR TEST TABLE <VEHICLES WITH AUTOMATIC AIR CONDITIONER>
Item No. | Drive object | Drive content
--- | --- | ---
01 | Blower motor | Stop
02 | Low speed
03 | Middle speed
04 | High speed
05 | Motor for air mixing door | Open angle: Approximately 0% (MAX COOL)
06 | Opening angle: approximately 50%
07 | Open angle: Approximately 100% (MAX HOT)
08 | Motor for mode selection switching damper | FACE
09 | FOOT
10 | DEF
11 | Compressor output | OFF
12 | ON
13 | Motor for air outside/inside air selection switching damper | Outside air
14 | Inside air
38 | Idle-up | OFF
39 | ON

[55] HEATER, AIR CONDITIONER AND VENTILATION - - HEATER AND AIR CONDITIONER SYSTEM | PRINT PAGE / INDEX / PRIOR / NEXT

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