In the LS400 automatic air conditioner 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 senses 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 LS430's automatic air conditioner system. With this technique, the data that has been fetched under varying environmental conditions is stored in the ECU, which effects control to provide enhanced air conditioner comfort.

*: Neural Network = Is capable of effecting complex control by artificially simulating the information processing method of the nervous system of living organisms in order to establish a complex input/output relationship that is similar to a human brain. 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 room 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 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 conditioner ECU controls the servo motors and blower motors in accordance with the control volumes that have been calculated by the neural network control

Normal Operation
* When the air inlet mode is selected in the automatic mode, the air conditioner ECU automatically switches the air inlet to the recirculation mode or to the fresh air mode by making a comprehensive analysis for preventing the intrusion of the harmful elements (CO, HC, NOx) that are present in the exhaust gases that are contained in the air outside of the vehicle, thus ensuring the maximum cooling performance in the summer and preventing the fogging of the windows in the winter. Also, when the automatic mode is selected, the air conditioner ECU automatically turns ON the compressor. However, to allow for the smog ventilation sensor to warm up, the automatic switching of the air inlet modes through the detection of the elements is not carried out for 30 seconds immediately after the engine is started.

Automatic Internal Air Cool Down Operation
* When the air inlet mode is in the automatic mode and the vehicle’s internal air temperature is high, such as in summer, the air conditioner ECU switches the air inlet mode to the recirculation mode in order to reduce the internal air temperature.

Automatic External Air Fogging Prevention Operation
* When the air inlet mode is in the automatic mode and the blower or the compressor is turned OFF through the manual operation of the switch or through automatic control, the air conditioner ECU switches the air inlet mode to the fresh air mode.

* When the outside air temperature is low, the air conditioner ECU automatically switches the air inlet mode to the fresh air mode in order to ensure the defogging performance of the window.

NOTE:
* The smog ventilation sensor cannot detect elements such as the smoke from a bonfire or factory exhaust, foul or animal odors, and dirt or dust particles. Therefore, the air inlet modes are not switched in accordance with those elements.

* Depending on the direction of the wind, the smog ventilation sensor might not be able to detect the exhaust gas elements, and could emit an odor.