System Description
WARNING: This page is about a different car, the 2011 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.
- GENERAL
- The air conditioning system has the following control.
Control Outline Neural Network Control This control is capable of effecting complex control by artificially simulating the information processing method of nervous system of living organisms in order to establish a complex input / output relationship that is similar to a human brain. Outlet Air Temperature Control In compliance with the temperature set at the temperature control switch, the neural network control calculates the outlet temperature based on the input signals from various sensors. The temperature setting for the driver and front passenger is controlled independently in order to provide a separate vehicle interior temperature for the right and left side. Thus, air conditioning that accommodates the occupants' preferences has been realized. Blower control Controls the blower motor in accordance with ten airflow volume that has been calculated by the neural network control based on the input signals from various sensors. Air Outlet Control Automatically switches the outlets in accordance with the airflow volume that has been calculated by the neural network control based on the input signals from various sensors. In accordance with the engine coolant temperature, outside air temperature, amount of sunlight, required blower outlet temperature, and vehicle speed conditions, this control automatically switches the blower outlet to the FOOT / DEF mode to prevent window from becoming fogged when the outside air temperature is low. Air Inlet Control automatically controls the air inlet control damper in accordance with the calculation of the required outlet air temperature. Drives the servomotor (for air inlet) according to the operation of the air inlet control switch and fixes the dampers in the FRESH or RECIRC position. Compressor Control This control turns OFF the magnetic clutch of the A/C compressor when the blower motor is turned OFF at the time the engine coolant temperature is below a predetermined value, an abnormal refrigerant pressure has been input, or the discharge temperature of the evaporator is below a predetermined value. Air conditioning amplifier turns the compressor off if the engine coolant temperature becomes abnormally hot (115°C (239°F) or above) when driving under a high load. Rear Window Defogger Control Switches the rear defogger and outside rear mirror heaters*1 on for 15 minutes when the rear defogger switch is switched on.
Switches them off if the switch is pressed while they are operating.Outer Temperature Indicator Control Based on the signals from the ambient temperature sensor, this control calculates the outside temperature, which is then corrected in the air conditioning amplifier, and shows in the A/C control assembly. Self-Diagnosis The DTC (Diagnostic Trouble Code) is stored in the memory when the air conditioning amplifier detects an abnormality in the air conditioning system. *1: Models with XLS and Limited Grades
- The air conditioning system has the following control.
- MODE POSITION AND DAMPER OPERATION
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002
FUNCTION OF MAIN DAMPERControl Damper Operation Position Damper Position Operation Air Inlet Control Damper FRESH A Brings in fresh air. RECIRCULATION B Recirculates internal air. Air Mix Control Damper MAX COLD to MAX HOT Temp. Setting C - D - E (C' - D' - E') T - U - V 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
DEFF, K, L, P, S Defrosts the windshield through the center defroster, side defroster, side registers and rear center register.
FOOT/DEFG, K, L, P, Q, X Defrosts the windshield through the center defroster, side defrosters, side registers, and rear center register, while air is also blown out from the front and rear foot well register ducts.
FOOTH, K, L, P, Q, X Air blows out of the foot well register duct, and side registers. In addition ,air blows out slightly form the center defroster and side defroster.
BI-LEVELI, K, N, P, R, X Air blows out of the front and rear center registers, side registers and front and rear foot well register ducts.
FACEI, J, M, O, S, W Air blows out of the front and rear center registers, and side registers. - AIR OUTLET AND AIRFLOW VOLUME
INDICATION (MODE) SELECTION
AUTO / MANUALFACE FOOT DEF CTR SIDE RR FR RR CTR SIDE A B C D E F G
(FACE - U)◦ / ◦
(B/L - U)◦ / ◦
(B/L - L)◦ / -
(FOOT - F)◦ / -
(FOOT - R)◦ / ◦
(FOOT - D)◦ / -
(F/D)◦ / ◦
(DEF)◦ / ◦ - NEURAL NETWORK CONTROL
- In the previous automatic air conditioning system, the ECU determined the required outlet air temperature and blower air volume in accordance with the calculation formula that has been obtained based on information received from the sensors.
However, because the sensors of a person are rather complex, a given temperature is sensed differently, depending on the environment in which the person is situated. For example, a given amount of solar radiation can feel comfortably warm in a cold climate, or extremely uncomfortable in a hot climate. Therefore, as a technique for effecting a higher level of control, a neural network has been adopted in the automatic air conditioning system. With this technique, the data that has been collected under varying environmental conditions is stored in the ECU, which effects control to provide enhanced air conditioning comfort.
- The neural network control consists of neurons in the input layer, intermediate layer and output layer. The input layer neurons process the input data of the outside temperature, the amount of sunlight, and the cabin temperature based on the outputs of the switches and sensors, and output them to the intermediate layer neurons. Based on this data, the intermediate layer neurons adjust the strength of the mediate layer neurons. based on this data, the intermediate layer neurons adjust the strength of the links among the neurons. The sum of these is then calculated by the output layer neurons in the form of the required outlet temperature, solar correction, target airflow volume, and outlet mode control volume. Accordingly, the air conditioning amplifier controls the servomotors and blower motor in accordance with the control volumes that have been calculated by the neural network control.
- In the previous automatic air conditioning system, the ECU determined the required outlet air temperature and blower air volume in accordance with the calculation formula that has been obtained based on information received from the sensors.
- SELF-DIAGNOSIS
- Air conditioning amplifier has a self-diagnosis function. It stores any operation failures in the air conditioning system memory in the form of DTC (Diagnostic Trouble Code).
- There are two methods for reading DTCs. One is to use Techstream, and the other is to read the DTC on the A/C control panel switch.
- DTCs are shown on the A/C control panel, and on Techstream.
- Air conditioning amplifier has a self-diagnosis function. It stores any operation failures in the air conditioning system memory in the form of DTC (Diagnostic Trouble Code).
- A/C CONTROL ASSEMBLY
- Push-button type A/C control assembly is used. The temperature control switches for the driver and front passenger are provided on the A/C control assembly to enhance their ease of use.
- AIR CONDITIONING UNIT
- A semi-center location air conditioner unit, in the evaporator and heater core are placed in the vehicle's longitudinal direction, is used. As a result, the air conditioning unit is made compact and lightweight.
- EVAPORATOR
- A revolutionary super-slim structure evaporator is used. Placing the tanks at the top and the bottom of the evaporator and adopting a micropore tube construction have realized the following effects:
- The heat exchanging efficiency is improved.
- The temperature distribution is made more uniform.
- The evaporator is made more thinner. 58 mm (2.3 in.) → 38 mm (1.5 in.)
- A revolutionary super-slim structure evaporator is used. Placing the tanks at the top and the bottom of the evaporator and adopting a micropore tube construction have realized the following effects:
- HEATER CORE
- A compact, lightweight, and highly efficient straight flow (full-path flow) aluminum heater core is used.
- BLOWER MOTOR
- The blower motor has an built-in blower controller, and is controlled with the duty control from the air conditioning amplifier.
- BUS CONNECTOR
- A bus connector is used in the wire harness connection that connects the servomotor from the air conditioning amplifier.
The bus connector has an built-in communication / drive IC which communicates with each servomotor connector, actuates the servomotor, and has a position detection function. This enables bus communication for the for the servo motor wire harness, for a more lightweight construction and a reduced number of wires.
- A bus connector is used in the wire harness connection that connects the servomotor from the air conditioning amplifier.
- SERVO MOTOR
- The pulse pattern type servomotor consists of a printed circuit board and servomotor. The printed circuit board has three contact points, and can transmit 2 ON-OFF signals to the air conditioning amplifier based on the difference of the pulse phase. The smart connector detects the damper position and movement direction with this signal.
- CLEAN AIR FILTER
- A clean air filter (micro dust and pollen filter) is used. This filter excels in the removal of dust and pollen. The filter made be disposed of easily as a combustible material, a feature that is provided in consideration of the environment.
- CONDENSER
- The condenser consists of two cooling portions: a condensing portion and a super-cooling portion, and also a gas-liquid separator. This condenser uses a sub-cool cycle that offers excellent heat-exchange performance.
- In the sub-cycle, after the refrigerant passes through the condensing portion of the condenser, both the liquid refrigerant and the gaseous refrigerant that could not be liquefied are cooled again in the super-cooling portion. Thus, the refrigerant is sent to the evaporator in an almost completely liquefied state.
- The condenser consists of two cooling portions: a condensing portion and a super-cooling portion, and also a gas-liquid separator. This condenser uses a sub-cool cycle that offers excellent heat-exchange performance.
- A/C COMPRESSOR
- A/C compressor is continuously variable capacity type in which its capacity varies in accordance with the cooling load of the air conditioning.
- This compressor consists of a shaft, lug plate, piston, shoe, crank, chamber, cylinder, and solenoid control valve.
- A solenoid control valve that adjusts the suction pressure so that the suction pressure can be controlled as desired is provided.
- The crank chamber is connected to the suction passage. A solenoid control valve is provided between the suction passage (LO pressure) and the discharge passage (HI pressure).
- The solenoid control valve operates under duty cycle control in accordance with the signals from air conditioning amplifier.
- 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.
- When the solenoid control valve opens (solenoid coil is not energized), the difference in pressure disappears. Then, the pressure is applied to the right side of the piston. Thus, the spring elongates and eliminates the tilt of the lug plate. As a result, there is no piston stroke and the discharge capacity turns to decrease.
- A/C compressor is continuously variable capacity type in which its capacity varies in accordance with the cooling load of the air conditioning.