JPS6225247A - Clouding removing device for window for vehicle - Google Patents

Abstract

PURPOSE:To perform the clouding removing work properly at all times by changing a criterion value before and after water absorption moisture of a humidity sensor is frozen. CONSTITUTION:The 1st and 2nd data having the relations of the electrical resistance values of the humidity sensor 1 in case an ambient temperature is higher and lower than the forecast freezing temperature with a temperature coefficient respectively are stored in a storage means 2. When the ambient temperature is higher (or lower) than the forecast freezing temperature, a temperature discriminating means 2a produces the 1st or the 2nd temperature discriminating signal in cooperation with a temperature detecting means 4. An arithmetic means 2c and 2d operates the 1st or the 2nd discriminating reference value from the 1st or 2nd stored data according to the temperature discriminating signal and produces a reference value signal. A clouding discriminating means 2e produces an output signal based on a comparison between a humidity detecting signal and the 1st or the 2nd reference value signal which is given to a dehumidifying means 3.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a defogging device for vehicle windows.

[Prior art]

Conventionally, in this type of fog removal device, Japanese Patent Application Laid-Open No. 58-1
As disclosed in Publication No. 60856, a humidity sensor detects the humidity in the vehicle interior just before fogging is predicted to occur on the vehicle windows, and based on this detection result, the fogging on the windows is effectively and timely removed. There is something I tried to do.

[Problem that the invention seeks to solve]

However, in such a configuration, when the ambient temperature is normal temperature, the above-mentioned humidity sensor changes the electric resistance value according to the degree of water absorption based on the action of absorbing moisture corresponding to the humidity. Since a type that detects humidity is used, when the moisture absorbed by the humidity sensor freezes due to a drop in ambient temperature, the detection characteristics of the humidity sensor change in a complicated manner compared to before freezing. Therefore,
In such a situation, the timing of the defogging device's operation and the time of fogging on the window do not necessarily match, causing the defogging device to operate when it is not needed or not to operate when it is needed. was there.

On the other hand, when the present inventors conducted an experiment on changes in the detection characteristics of the above-mentioned humidity sensor due to temperature, it was observed that the electrical resistance value of the humidity sensor was significantly different before and after freezing the absorbed moisture. By the way, each relative humidity is 70% RH, 80
A graph showing the relationship between the electrical resistance value of the humidity sensor and the ambient temperature at %RH and 90%RH is shown in FIG. This allows freezing temperatures (e.g. 0°C)
In the following it will be understood that the electrical resistance value of the humidity sensor changes linearly with a larger temperature coefficient than above the freezing temperature.

Therefore, in order to deal with the above-mentioned problems, the present invention provides a defrosting device for vehicle windows, based on the above-mentioned experimental results, which detects the humidity sensor even if the moisture absorbed by the humidity sensor is frozen. Based on the results, the objective is to ensure that the fog removal action is always performed normally.

[Means for solving problems]

In solving this problem, the structural features of the present invention are as follows:
As shown in FIG. 1, there is provided a humidity detection means 1 that detects the humidity in the cabin of a vehicle and generates a humidity detection signal, and a humidity detection means 1 that determines whether or not it is necessary to defog the windows of the vehicle according to the humidity detection signal. In a fog removing device, the dehumidifying device includes a determining means 2 that generates an output signal when the humidity is required, and a dehumidifying means 3 that performs the dehumidifying action necessary to defog the window in response to the output signal. A humidity sensor that causes a temperature coefficient of an electrical resistance value that changes depending on the degree of water absorption when water is absorbed to be different on both sides of a predicted freezing temperature of the absorbed water, and generates the electrical resistance value as the humidity detection signal. constitutes a humidity detection means l, and includes a temperature detection means 4 which detects the ambient temperature of the humidity sensor 1 and generates a temperature detection signal, and when the value of the temperature detection signal is higher than the predicted freezing temperature, a first
Temperature discrimination means 2.a generates a temperature discrimination signal and generates a second temperature discrimination signal when the temperature is low, and has a temperature change tendency similar to the temperature change tendency of the electrical resistance value on the side higher than the predicted freezing temperature of the ambient temperature. first data representing the relationship between the first discrimination reference value determined as above and the ambient temperature; Storage means 2 for storing second data representing the relationship between the second discrimination reference value and the ambient temperature
b, and a first calculation means 2c which calculates the first discrimination reference value according to the temperature detection signal based on the first stored data in response to the first temperature discrimination signal, and generates the first discrimination reference value as a first reference value signal. and a second calculation means 2d which calculates the second discrimination reference value according to the temperature detection signal based on the second stored data in response to the second temperature discrimination signal and generates the second discrimination reference value as a second reference value signal; The humidity detection signal is transmitted to the first (or second)
The determining means 2 is comprised of a fogging determining means 2e which generates the output signal when it is determined that defogging of the window is necessary by comparison with the reference value signal of ).

[Function and effect]

Therefore, in the present invention configured in this way, each temperature coefficient of the electrical resistance value of the humidity sensor 1 is uniquely determined to be a different value when the ambient temperature is higher than the predicted freezing temperature and when it is lower than the predicted freezing temperature. The first and second data, each having a temperature change tendency similar to the temperature change tendency due to the relationship with the temperature coefficient of the electric resistance value, are determined and stored in the storage means 2b, and the ambient temperature is is higher or lower than the predicted freezing temperature, the temperature determining means 2a cooperates with the temperature detecting means 4 to detect the first
A first (or second) temperature discrimination signal is generated, and a first (or second) operator 12c (or 2d) responds to the first (or second) temperature discrimination signal. 2nd)
A first (or second) discrimination reference value is calculated according to the temperature detection signal from the stored data of the first (or second).
The color discrimination means 2e selectively generates an output signal based on a comparison between the humidity detection signal and the first (or second) reference value signal and applies it to the dehumidification means 3. Therefore, no matter what the ambient temperature is, the humidity detection signal from the humidity sensor 1 must match the temperature change trend on one side (or the other side) of the predicted freezing temperature as a judgment criterion. The necessity of the output signal is determined based on the determined first (or second) discrimination reference value, and as a result, of course, if the absorbed water is not frozen, the absorbed water is frozen. Even if the dehumidifying means 3 is not driven, the driving timing and non-driving timing of the dehumidifying means 3 can always be reliably matched to the fogging period and the non-fogging period of the window.

〔Example〕

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings.
The figure shows an example of a defogging device for a vehicle window according to the present invention, which includes a humidity sensor 10, a temperature sensor 20, and a device connected to the humidity sensor 10 and temperature sensor 20, respectively. each A-D converter 30.40;
It is composed of a microcomputer 50 connected to both of these A-D converters 30 and 40, and a dehumidification mechanism 60 connected to this microcomputer 50.

The humidity sensor 10 is disposed at a suitable position on the rear window in the vehicle interior, and the humidity sensor 10 includes:
A type having the characteristics shown in FIG. 2 has been adopted. In such a case, the humidity sensor 10 is a room temperature type humidity sensor whose main components are WO3 and glass, and the moisture absorption degree (i.e., relative humidity) corresponding to the humidity on the humidity sensing surface of this humidity sensor is set as a parameter. As shown in Figure 2, the electrical resistance value of the same humidity sensor changes depending on the ambient temperature at 0°C.
It changes linearly with different slopes. However,
The humidity sensor 10 generates an electrical resistance value corresponding to the humidity as a humidity detection signal.

The temperature sensor 20 is connected to the humidity sensor 10 in the cabin of the vehicle.
The temperature sensor 20 detects the ambient temperature of the humidity sensor 10 and generates a temperature detection signal. The A-D converter 30 digitally converts the humidity detection signal from the humidity sensor 10 into a digital humidity signal;
-D converter 40 digitally converts the temperature detection signal from temperature sensor 20 into a digital temperature signal. The microcomputer 50 executes a computer program prestored in its dedicated memory in cooperation with each A-D converter 30, 40 according to the flowchart shown in FIG. Performs calculation processing necessary for control. The dehumidifying mechanism 60 performs a dehumidifying action under the control of the microcomputer 50 to remove fog from the rear window.

In this embodiment configured as described above, the ambient temperature is 0.
If the present invention is operated at a temperature higher than °C, the microcomputer 50 starts executing the computer program in step 70 according to the flowchart of FIG. By A
- A digital temperature signal generated from the D converter 40 is input. However, at this stage, since the ambient temperature of the humidity sensor 10 is higher than 0°C as described above, the value of the digital temperature signal in step 71 (hereinafter referred to as the digital temperature value t)
) is higher than the predicted freezing temperature LO, and the microcomputer 50 determines [NOJ] in step 72. However, in this embodiment, the predicted freezing temperature to is 0° C. and is stored in advance in the continuous memory of the microcomputer 50.

When the computer program proceeds to step 73, the microcomputer 50 calculates the first discrimination value r according to the digital temperature value t in step 71 based on the following linear equation (11).

r=at+b...+11 However, as shown in FIG. 5, the symbol a represents the negative slope of the linear equation (1), and the symbol s represents the positive intercept of the linear equation (11). r corresponds to the upper limit of the electrical resistance value of the humidity sensor 10 that requires dehumidification of the vehicle interior (i.e., defogging of the rear window) at t>Q°C.
This corresponds to the temperature coefficient of the electrical resistance value of the humidity sensor 10 at >0°C. Note that the linear equation (11) has been previously stored in the memory dedicated to successive output of the microcomputer 50.

After completing the calculation in step 73 as described above,
The microcomputer 50 receives the digital humidity signal generated by the cooperation with the humidity sensor 10 from the A/D converter 30 in step 74 and advances the computer program to step 75.

At this stage, if the value of the digital humidity signal in step 74 (hereinafter referred to as digital humidity value H) is larger than the first determination value in step 73, the microcomputer 50 determines in step 75 that it is rNOJ. This means that generation of an output signal necessary for driving the defogging mechanism 60 is prohibited based on the judgment that the rear window is not fogged. On the other hand, if the determination in step 75 is rYESJ, the microcomputer 50 generates an output signal in step 79, and in response, the dehumidification mechanism 60 dehumidifies the interior of the vehicle to fog the rear window. remove.

As understood from the above explanation, step 72
If the determination in step 7 is "NO", step 7
3, the first judgment value “is the digital temperature value t(>Q°C
), and since the determination in step 75 is based on the first judgment value r, the electrical resistance values of the humidity sensor 10 both exhibit the same tendency to change in response to changes in ambient temperature. Based on the first judgment value r, the necessity of dehumidification (that is, removing fog from the rear window) is always determined correctly and in a timely manner, and as a result, the dehumidification mechanism 60
The operating timing and the fogging generation timing of the rear window can always coincide.

In such a state, when the ambient temperature drops below 0°C and the determination in step 72 becomes rYESJ, the microcomputer 50 in the next step 76 calculates the digital temperature in step 71 based on the following linear equation (2). A second discrimination value R is calculated according to the value t.

R=A t +B...(1) However, the code A
As shown in FIG. 5, represents the negative slope of the linear equation (2), and symbol B represents the positive intercept of the linear equation (2). Further, the second judgment value R is the dehumidification of the vehicle interior (i.e.,
This corresponds to the upper limit of the electrical resistance value of the humidity sensor 10 that requires defogging of the rear window. Moreover, the slope A is the temperature coefficient of the electrical resistance value of the humidity sensor 10 at t≦0°C (t>
(larger than the case of Q'C). It should be noted that the linear equation (2) is already stored in the memory for continuous use of the microcomputer 50 in advance.

After completing the calculation in step 76 as described above,
The microcomputer 50 receives the digital humidity signal generated by the cooperation with the humidity sensor 10 from the A/D converter 30 in step 77 and advances the computer program to step 78.

At this stage, if the digital humidity value H in step 77 is greater than the second judgment value R in step 76, the microcomputer 50 determines "N" in step 77.
O”. This means that generation of an output signal is prohibited based on the determination that the rear window is not fogged. On the other hand, the determination in step 78 is rYESJ.
If so, the microcomputer 50 generates an output signal in step 79, and in response to this, the dehumidifying mechanism 60 dehumidifies the interior of the vehicle and removes the moisture from the rear window.

As understood from the above explanation, step 72
If the determination in step 76 is rYESJ, the second determination value R in step 76 is the digital temperature value t (5
0° C.), and step 78
Since the determination in is made based on the second judgment value R, dehumidification is performed based on the electrical resistance value of the humidity sensor 10 and the second judgment value R, both of which show similar change trends in response to changes in the ambient temperature below 0°C. (In other words, whether or not to remove fog from the rear window) is always correctly and timely determined. The timing of cloudy occurrence can always coincide with that of cloudy weather.

In the above embodiment, the humidity sensor 10 is a humidity sensor whose temperature coefficient of electrical resistance changes with 0°C as a boundary.
Although we have described an example in which 0
A humidity sensor whose temperature coefficient of electrical resistance value changes before and after a temperature other than °C may be employed as the humidity sensor 10.

[Brief explanation of drawings]

FIG. 1 is a diagram corresponding to the structure of the claimed invention, FIG. 2 is a graph showing the relationship between the electrical resistance value of the humidity sensor and the ambient temperature using relative humidity as a parameter, and FIG. 3 is a graph showing the invention according to the present invention. FIG. 4 is a block diagram showing one embodiment, FIG. 4 is a flowchart showing the operation of the microcomputer in FIG. 3, and FIG. 5 shows the relationship between the first and second judgment values r and the digital temperature value t of R. This is a graph showing. Explanation of symbols 10...humidity sensor, 20...temperature sensor, 30.
40...A-D converter, 50...Microcomputer, 60...Dehumidification mechanism.

Claims (1)

[Claims] Humidity detection means detects the humidity inside the vehicle interior and generates a humidity detection signal, and determines whether or not defogging of the windows of the vehicle is necessary based on the humidity detection signal, and generates an output signal when defogging is necessary. In a fog removing device comprising a determining means and a dehumidifying means for performing a dehumidifying action necessary for defogging a window in response to the output signal, when moisture corresponding to the humidity is absorbed, a change is made in accordance with the degree of water absorption. The humidity detecting means is configured by a humidity sensor that makes the temperature coefficient of the electrical resistance value different on both sides of the predicted freezing temperature of the absorbed water and generates the electrical resistance value as the humidity detection signal, Temperature detection means is provided to detect the ambient temperature of the sensor and generate a temperature detection signal, and when the value of the temperature detection signal is higher than the predicted freezing temperature, a first temperature discrimination signal is generated, and when it is lower, a second temperature discrimination signal is generated. a first temperature determining means that is determined to have a temperature change tendency similar to the temperature change tendency of the electrical resistance value on the side higher than the predicted freezing temperature of the ambient temperature;
First data representing the relationship between the discrimination reference value and ambient temperature, and second discrimination determined to have a temperature change tendency similar to the temperature change tendency of the electrical resistance value on the side of the ambient temperature lower than the predicted freezing temperature. storage means for storing second data representing a relationship between a reference value and an ambient temperature; and a first determination reference value based on the first stored data in response to the first temperature determination signal and in response to the temperature detection signal. a first calculation means for calculating and generating a first reference value signal; and a first calculation means for calculating the second discrimination reference value in response to the second temperature discrimination signal based on the second stored data and in response to the temperature detection signal. a second calculation means that generates a second reference value signal; and a second calculation means that generates a second reference value signal;
Alternatively, the vehicle is characterized in that the determining means comprises fogging determining means that generates the output signal when it is determined that defogging the window is necessary by comparing it with the second) reference value signal. Defog device for windows.