JPH0314133B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improvement in an automatic air conditioning control system for a vehicle that performs an air pollution detection method that matches the olfactory characteristics of humans. 2. Description of the Related Art Conventionally, it is known that vehicles are equipped with automatic air conditioning control devices. An automatic air conditioning control system for a vehicle has gas sensors installed inside and outside the vehicle cabin.The internal and external gas sensors sense the degree of contamination inside and outside the vehicle cabin, and a computer processes this data as data to control the operation of the damper and blower motor. It operates to appropriately select the state of outside air introduction, ventilation, or inside air circulation. Specifically, if the level of pollution from cigarette smoke or carbon dioxide gas (CO ₂ ) associated with unpleasant crowds increases in the cabin, it will be necessary to introduce clean outside air, and if the level of pollution inside the cabin decreases, it will be necessary to introduce clean outside air. All you have to do is circulate your inner air. However, when attempting to actually operate the vehicle air conditioning control device automatically based on the degree of contamination in the vehicle interior, the following problems arise. In other words, if the air inside the vehicle is dirty and the air outside the vehicle is clean, ventilation will be activated, but whether or not the air inside the vehicle is dirty is related to the sense of smell of the occupants, and is not just a function of ventilation. It is extremely difficult to accurately detect and judge whether or not something is contaminated using a gas sensor that detects physical reality. In other words, it is not possible to make the decision to introduce clean outside air because the air inside the vehicle is dirty using the same intuition as a human being. The air conditioning control devices proposed in the past have been unable to perform satisfactory air conditioning control because the methods for detecting dirt in the vehicle interior have been insufficient as described above. In view of the above-mentioned problems, the present inventor has created the present invention to effectively solve the problems. An object of the present invention is to make a method for detecting the level of cigarette smoke concentration and CO ₂ concentration in a vehicle interior similar to the human olfactory characteristics in a vehicle automatic air conditioning control system, and thereby to detect contamination in the vehicle interior. The purpose of this technology is to make judgments similar to how humans feel, allowing for effective air conditioning control. The feature of the present invention is that, in an automatic air conditioning control device for a vehicle, the average value of the pollution sensor output within a predetermined time and the pollution detection threshold level set to be a certain amount larger than the pollution sensor output. and, if the output of the comparison means becomes smaller than the certain amount, the contamination detection threshold level is arbitrarily set to a level that is undetectable to the human sense of smell. While changing the rate of change, the pollution sensor output value is
The present invention is configured such that when the contamination detection threshold level is exceeded, it is determined that there is a contamination state. Embodiments of the present invention will be described below based on the accompanying drawings. The principle of the air pollution detection method according to the present invention will be outlined. An object of the present invention is to provide an automatic air conditioning control system for a vehicle that has standards for determining contamination that are similar to human feelings. In order to realize such an air conditioning control device, we will focus on the following pollution conditions and human olfactory characteristics. (1) The concentration of exhaust gas inside and outside the vehicle, the amount of cigarette smoke, etc. change relatively rapidly. (2) The human sense of smell cannot detect air pollution that changes slowly.
Also, your sense of smell gradually adapts, so you no longer find it unpleasant. Therefore, by utilizing the above property, a slow change in sensor output that cannot be detected by the human sense of smell is not judged to be contaminated, but only a rapid change in sensor output that can be detected by the human sense of smell is considered to be contaminated. It uses the principle of judgment to detect contamination. Next, specific examples will be shown. FIG. 1 shows a block diagram of an air conditioning control device. 1 is a computer forming a control circuit. On the input side of the computer 1, an outside air gas sensor 2 mainly for detecting exhaust gas and an inside air gas sensor 3 mainly for detecting cigarette smoke are provided. is input into the computer 1. On the output side of the computer 1, as objects to be controlled, there is a blower 6 installed in a duct 5 that forms an air flow path provided in the automobile, and an outside air blower 6 formed in a bifurcated shape on the upstream side of the duct 5. There is a switching damper 9 provided at the confluence of the intake duct 7 and the inside air intake duct 8, and the motor 6a of the blower 6
A drive control signal is output from the computer 1 to the actuator 10 of the damper 9 and the damper 9 via a damper drive circuit 11 and a blower drive circuit 12, respectively. In addition, as a gas sensor that detects cigarette smoke, electrodes are connected to a metal oxide semiconductor element whose main component is SnO ₂ whose resistance value changes due to adsorption and desorption of smoke, and the output voltage is measured. Possible examples include semiconductor gas sensors that detect smoke concentration and photoelectric gas sensors that utilize the fact that the amount of light received by a light-receiving element that receives light emitted from a light-emitting element changes depending on the smoke concentration. According to the above configuration, the computer 1 performs necessary signal processing based on the contamination information from the gas sensors 2 and 3, and the damper 9,
The blower 6 is operated appropriately to automatically control air conditioning according to the state of pollution inside and outside the vehicle interior. In the above signal processing, it is determined whether the air inside or outside the vehicle is contaminated based on the sensing outputs of the gas sensors 2 and 3, and an air pollution detection method according to the present invention as described below is executed. . Next, the output characteristics of the gas sensors 2 and 3 and the air pollution detection method will be explained. The gas sensor 3 that detects the concentration of cigarette smoke will be described below as an example. FIG. 2 shows an example of changes in the output of the gas sensor 3 over time, and FIG. 3 is a diagram showing in detail the process of detecting cigarette smoke concentration by the gas sensor 3. Figure 4 shows computer 1
FIG. 2 is a flowchart relating to air conditioning control executed within the vehicle. In FIG. 2, the output of the gas sensor 3 outputs an analog signal such as a voltage depending on the degree of cigarette smoke concentration in the vehicle interior, and in this case, as the degree of cigarette smoke concentration gradually increases, the sensor output a increases as the degree of cigarette smoke concentration increases. gradually increases in proportion to On the other hand, a cigarette smoke concentration detection threshold level b, which is larger by a certain amount than the sensor output, is set for the sensor output a. This threshold level b is created in the computer 1, and the sensor output a changes at a speed within a certain range between the upper limit value a ₁ and the lower limit value a ₂ which are predetermined due to the characteristics. It is generated so as to follow the sensor output a as long as it changes. When the sensor output a is below the lower limit value a ₂ or above the upper limit a ₁ , the threshold level b is set to a constant value such that it becomes the lower limit value a ₂ or the upper limit value a ₁ . Set. As mentioned above, the lower limit value _a2 was set because below the lower limit value, the concentration of cigarette smoke in the passenger compartment is so low that humans cannot detect it, so the air in the passenger compartment is always clean regardless of changes in the sensor output. On the other hand, the upper limit value _a1 was set because above the upper limit value, the concentration of cigarette smoke in the passenger compartment is so high that humans cannot adapt to it, so it is determined that This is because it is determined that the cabin air is always dirty regardless of the situation. In the above, when the change in the sensor output a between the lower limit value a ₂ and the upper limit value a ₁ is slow, the change in the threshold level b is also a value larger than the sensor output a by a certain value. In this case, since the sensor output does not exceed the threshold level, it is determined that the cabin air is clean. On the other hand, if the sensor output a suddenly changes and the change in the threshold level b cannot follow this change, the sensor output exceeds the threshold level and it is determined that the cabin air is contaminated. In FIG. 3, the variation range c of the detection target determined by the upper limit value _a1 and the lower limit value _a2 is divided into, for example, 115 steps. When the sensor output a changes slowly in the change range c, the threshold level b is a value larger than the sensor output and follows the sensor output a while ensuring a certain detection margin d of, for example, 25 steps. and change. Therefore, inside the computer 1, arithmetic processing is performed to change the threshold level b while checking changes in the sensor output a of the gas sensor 3. Although the gas sensor 3 that detects the concentration of cigarette smoke in the air inside the vehicle has been described above, the same applies to the air pollution detection method related to the gas sensor 2 that detects the degree of pollution in the air outside the vehicle. However, since the gas sensor 2 is primarily a sensor for exhaust gas, and the gas sensor 3 is primarily a sensor for cigarette smoke, there are some differences in sensor output characteristics. In this way, it is determined whether the air is clean or dirty inside or outside the vehicle interior, and based on the determination whether the air is clean or dirty inside or outside the vehicle interior, outside air introduction, ventilation, or inside air circulation for air conditioning is selected. In FIG. 4, in the air conditioning control device according to the present invention, in process 13, the contamination state of the inside air and outside air in the vehicle is determined by the above-described detection method, and in process 14, the contents of the current output memory storing the control mode are determined. a main routine that outputs and executes a required control state corresponding to the contents of the current output memory; a subroutine 15 that changes the threshold level; The control program includes a subroutine 16 for setting delay times. The main routine above is executed repeatedly, for example every 0.2 seconds, and
17, a subroutine 15 is activated every 15 seconds to check the threshold level. Also, subroutine 16 for setting the delay time.
is configured to be executed only when the determination of the contamination state is different between the previous state and the new state as a result of the process 13 related to the determination of the inside and outside air contamination state (determination 18). In the above main routine, first the initial settings
At step 19, after the sensor output is stabilized, an initial threshold level is set and a threshold level change timer is set. The threshold level change timer is set to 15 seconds, for example, so that the threshold level is checked and changed every 15 seconds in subroutine 15 in response to changes in the sensor output signal as described above. Next, in process 20, the outputs of the sensors 2 and 3 are read, and in process 21, data related to the sensor outputs are integrated. Thereafter, if 15 seconds have not elapsed, the degree of contamination of inside air and outside air is determined separately based on the above-described air pollution detection method (process 13). Combinations of contamination states of inside air and outside air and control modes are made to correspond as shown in the following table.

[Table] The control mode determined as described above is stored in the next output memory. If the control mode of the contents of the current output memory is equal to the control mode of the contents of the next output memory, the contents of the current output memory are outputted in process 14, and the damper 9 and blower 6
control will be carried out. The contents of the current output memory and the contents of the next output memory become equal when the previous contamination state and the new contamination state are continuously equal for a predetermined period of time or more. Subroutine 15 for changing the threshold level is executed after data integration (process 21) has been performed for 15 seconds (decision 17). First, the average value of the sensor output signal for 15 seconds is calculated using the following equation. Average value = Added value of sensor output / Number of additions Then, the difference between the above average value and its threshold level is taken, and if the difference is larger than the detection margin d, the threshold level is lowered by, for example, one step (processing 22 ), when it is equal to the detection margin d, the current state is maintained (process 23), and when it is smaller than the detection margin d, the threshold level b is changed, for example, by raising it by one step (process 24). The amount by which the threshold level is changed is not limited to the one step described above, but can be set arbitrarily. However, this rate of change is determined to be constant and slow enough to be undetectable to the human sense of smell. Thereafter, the threshold level change timer is reset in process 25, and thus 15
The threshold level is checked every second, and by executing the subroutine 15, the threshold level b becomes the sensor output signal a.
It changes as if it follows the change in . However, since the rate of change in the threshold level b is slow enough to be undetectable to the human sense of smell and is set to be constant, the change in the sensor output signal a is If the area is loose like area A in the figure, it is possible to follow it while maintaining the detection margin d, but if it changes rapidly like area B or D, it cannot be followed immediately. As a result, the sensor output in areas B and D exceeds the threshold level b, and it is determined that the area is contaminated. Specifically, suppose sensor output signal a is 15 seconds/
If the change is more gradual than a step,
Threshold level b is 25 for sensor output signal a.
An appropriate detection margin for the step can be maintained. For example, as shown in areas B and C, if the sensor output signal a increases by 50 steps at a time and maintains that state, it will be determined that it is "contaminated" for about 6 minutes; Appropriate detection margin is achieved after 1 minute. After the sensor output signal a exceeds the threshold level b, the required air conditioning control is performed until the threshold level b becomes larger than the sensor output signal a again. Next, subroutine 1 to set the delay time
Regarding 6, shyness determined by process 13,
If the determination of the pollution state of the outside air is different from the previous determination, it is necessary to take a control mode that corresponds to the new pollution state.
A certain delay time is set before executing a new control mode. Specific examples (some of them) are shown in the table below.

[Table] Therefore, according to the above table, if the judgment of the contamination state of inside air and outside air is different, the control mode is determined for the new judgment, but the method of change from the previous state to the new state is A delay time N is set in the delay timer T correspondingly. Such a program is executed in subroutine 16. After the delay time N is set in the delay timer T, the main routine is repeated, during which the delay timer T is set to 0.
The contents of the next output memory are transferred to the contents of the current output memory on the condition that ). However, if a new contamination state is determined again during execution of the above main routine, subroutine 16 is executed via judgment 18, a control mode corresponding to the new contamination state is determined, and a change in the contamination state is determined. The corresponding delay time N will be set in the timer memory again. The reason for setting the delay time as above is in process 13.
This is to provide time for confirming that the determination made by the above is reliable. As is clear from the above embodiments, the present invention employs the principles 1 and 2 above in detecting the pollution state of the air inside and outside the vehicle interior and automatically controlling the air conditioner in response to the pollution state. It was configured to be able to detect contamination using the same feeling as humans. As is clear from the above description, according to the present invention,
The contamination detection threshold level is less affected by sudden changes in sensor output values, making it possible to determine air contamination close to the human olfactory feeling, improving ride comfort and livability. Ta.

[Brief explanation of the drawing]

Figure 1 is a block diagram of the air conditioning control system;
The figure is a graph showing changes in the output of the gas sensor, Figure 3 is a graph showing in detail an example of the process of detecting contamination by the gas sensor, and Figure 4 is a graph showing the process of detecting contamination.
It is a flowchart diagram concerning air conditioning control. In the drawing, 1 is a computer, 2 is an outside air gas sensor, 3 is an inside air gas sensor, 6 is a blower, 9 is a damper, 15 is a subroutine for changing the threshold level,
16 is a delay time setting subroutine, a is a sensor output signal, and b is a contamination detection threshold level.

Claims (1)

[Claims] 1. In the automatic air conditioning control system inside the vehicle, the average value of the pollution sensor output within a predetermined period of time is compared with a pollution detection threshold level set to be a certain amount larger than the pollution sensor output at predetermined time intervals. and when the output of the comparing means becomes smaller than the predetermined amount, the contamination detection threshold level is changed at an arbitrarily determined rate of change that is not perceptible to the human sense of smell. In addition, a method for detecting contamination in an automatic air conditioning control device for a vehicle, characterized in that a contamination state is determined when the output value of the contamination sensor exceeds the contamination detection threshold level.