JP4366781B2 - Air conditioner for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle air conditioner that performs air conditioning control based on a detection value of a humidity sensor.
[0002]
[Prior art]
As a prior art, there is a vehicle air conditioner disclosed in JP-A-7-285320. This vehicle air conditioner has a determination means for determining a failure of the humidity sensor. The determination means, for example, compares the detected value of the humidity sensor when the refrigerant compressor of the refrigeration cycle is switched from the off state to the on state with the detected value of the humidity sensor when a predetermined time has elapsed, and there is no change. In this case, it is determined that the humidity sensor has failed.
If the determination means determines that the humidity sensor has failed, air conditioning control is performed to prevent fogging of the window glass regardless of the detection value of the humidity sensor.
[0003]
[Problems to be solved by the invention]
However, the types of failure of the humidity sensor include failure of characteristic variation due to dust adhering to the humidity sensor itself or mixing of electrical noise, in addition to disconnection or short circuit that can be clearly identified as failure. In this case, in the air conditioning control according to the prior art, the function of the humidity sensor is normal, but the determination unit determines that the humidity sensor has failed, and as a result, the use of the humidity sensor is stopped. After that, even when the failure factor of the characteristic variation is removed and the humidity sensor returns to normal, there is a problem that the air conditioning control using the humidity sensor cannot be executed.
[0004]
In addition, since it is determined whether or not the humidity sensor has failed by a single failure determination process, as described above, although the function of the humidity sensor is normal due to adhesion of dust or the like, There is a high possibility that it will be erroneously determined as “humidity sensor failure”.
Further, even if the refrigerant compressor is operated while the vehicle window glass is open, the humidity in the passenger compartment hardly changes. Therefore, the failure determination of the humidity sensor is performed in this state (the window glass is open). Although the humidity sensor is normal, it is determined that the humidity sensor has failed.
The present invention has been made based on the above circumstances, and an object of the present invention is to provide a vehicle air conditioner capable of more accurately performing a failure determination of a humidity sensor.
[0013]
[Means for Solving the Problems]
(Means of Claim 1 )
The vehicle air conditioner of the present invention includes sensor abnormality determination means for determining whether or not there is an abnormality in the humidity sensor based on on / off switching of the refrigerant compressor, and window glass determination means for determining the open / closed state of the window glass. .
The sensor abnormality determination means determines whether or not there is an abnormality in the humidity sensor based on the on / off switching of the refrigerant compressor only when the window glass of the vehicle is closed.
According to said structure, since abnormality determination of a humidity sensor is not performed in the state in which the window glass is open, the erroneous determination of a sensor abnormality determination means can be prevented.
In addition, the window glass determination means, when the vehicle interior temperature after a certain time has elapsed since the start of air conditioning in the vehicle interior is Tr1, and the set temperature in the vehicle interior is Tset,
Tset−judgment value ≦ Tr1 ≦ Tset + judgment value …… (1)
When the relationship (1) is established, it is determined that the window glass is closed.
Thereby, when the relationship (1) is established, it is possible to determine whether the humidity sensor is abnormal.
[0014]
(Means of Claim 2 )
The vehicle air conditioner of the present invention includes sensor abnormality determination means for determining whether or not there is an abnormality in the humidity sensor based on on / off switching of the refrigerant compressor, and window glass determination means for determining the open / closed state of the window glass. .
The sensor abnormality determination means determines whether or not there is an abnormality in the humidity sensor based on the on / off switching of the refrigerant compressor only when the window glass of the vehicle is closed.
According to said structure, since abnormality determination of a humidity sensor is not performed in the state in which the window glass is open, the erroneous determination of a sensor abnormality determination means can be prevented.
In addition, the window glass determination means, when the current vehicle interior temperature is Tr, and the current outside air temperature is Tam,
Tam−judgment value ≦ Tr ≦ Tam + judgment value (2)
When the relationship (2) is established continuously for a certain period of time, it is determined that the window glass is open. Thereby, when the relationship (2) is established, the abnormality determination of the humidity sensor is not performed, and when the relationship (2) is not established, the abnormality determination of the humidity sensor can be performed.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, the vehicle air conditioner of this invention is demonstrated based on drawing.
(First embodiment)
FIG. 1 is an overall configuration diagram of a vehicle air conditioner 1.
The vehicle air conditioner 1 according to the present embodiment includes a duct 2 that guides conditioned air into the passenger compartment, a blower 3 that introduces air into the passenger compartment 2 and blows air into the passenger compartment, and cooling means for cooling the blown air. From the refrigeration cycle 4 to be performed, the heater core 5 for heating the blown air, the air mix door 6 for adjusting the mixing ratio of the cold air and the hot air, the air conditioner control device (hereinafter referred to as ECU 7) for controlling the operation of the system, and the like Composed.
[0016]
The duct 2 is composed of a plurality of branch ducts (not shown) on the air downstream side of the heater core 5, and downstream end openings of these branch ducts are connected to a plurality of outlets (not shown) that open into the vehicle interior. The upstream end opening of the branch duct is selectively opened and closed by an unillustrated outlet switching door.
The blower 3 includes a centrifugal fan 3a and a blower motor 3b accommodated in the blower case 8. The blower case 8 is formed with an inside air introduction port 9 and an outside air introduction port 10, and both the introduction ports 9 and 10 are selectively opened and closed by an inside / outside air switching door 11.
[0017]
The refrigeration cycle 4 is a very well-known one mounted on a car air conditioner. The refrigerant compressor 17 includes a refrigerant compressor (compressor 12), a refrigerant condenser 13, a receiver 14, an expansion valve 15, and a refrigerant evaporator 16. The refrigerant evaporator 16 is arranged in the duct 2.
The heater core 5 is disposed in the duct 2 on the air downstream side of the refrigerant evaporator 16 and heats the blown air passing through the heater core 5 using engine cooling water (warm water) flowing through the heater core 5 as a heat source.
[0018]
ECU7 is an electronic control unit computing equation of the control program and various related to the air conditioning control is built an input micro computer (not shown), sensor abnormality determining means, the sensor return determining means, sensor function determining means, compression The operation state of the system is electronically controlled based on sensor signals transmitted from various sensors (described later) and operation signals output from the A / C operation panel 18.
[0019]
The various sensors include an inside air temperature sensor 19 that detects the temperature inside the vehicle, an outside air temperature sensor 20 that detects the outside temperature of the vehicle, a solar radiation sensor 21 that detects the amount of solar radiation, and a post-evaporation that detects the temperature of the air cooled by the refrigerant evaporator 16. There are a temperature sensor 22, a water temperature sensor (not shown) for detecting the temperature of the engine cooling water, a humidity sensor 23 for detecting the relative humidity in the vehicle compartment, and the like.
[0020]
The A / C operation panel 18 is arranged on an instrument panel in the passenger compartment, and as shown in FIG. 2, an A / C switch 24 for switching ON / OFF of the refrigeration cycle 4 and an inside / outside air switching switch for selecting a suction port mode. 25, an air volume setting lever 26 for setting an air flow level, a temperature setting lever 27 for setting an indoor temperature, an air outlet mode changeover switch group 28 for selecting an air outlet mode (FACE mode, B / L mode, FOOT mode, F / D mode, DEF mode), an ECO switch 29 for setting economy operation, and the like are provided.
[0021]
Next, an abnormality determination method for the humidity sensor 23 by the ECU 7 will be described.
a) A first abnormality determination method will be described with reference to FIG.
When the detected value of the humidity sensor 23 when the compressor 12 is switched from OFF to ON is RHb, and the detected value of the humidity sensor 23 when a predetermined time (for example, 5 minutes) has elapsed since the compressor 12 is switched ON is RHnew, When the relationship (1) is established, an abnormality is determined (error).
(RHb−RHnew) <5% …………………… ▲ 1 ▼
This relationship (1) indicates that the detected value of the humidity sensor 23 does not decrease despite the compressor 12 being operated.
[0022]
b) A second abnormality determination method will be described with reference to FIG.
Humidity when a predetermined time (for example, 5 minutes) has passed since the detected value of the humidity sensor 23 when the compressor 12 is switched from ON to OFF after being turned on for more than a predetermined time (for example, 5 minutes). When the detection value of the sensor 23 is RHnew1, an abnormality determination (error) is made when the following relationship (2) is established.
(RHnew1-RHb1) <5% …………………… (2)
This relationship (2) indicates that the detected value of the humidity sensor 23 does not increase even though the compressor 12 is stopped.
[0023]
Next, a normal determination method of the humidity sensor 23 by the ECU 7 will be described.
c) A first normality determination method will be described with reference to FIG.
When the detected value of the humidity sensor 23 when the compressor 12 is switched from OFF to ON is RHb2, and when the detected value of the humidity sensor 23 is RHnew2 when a predetermined time (for example, 5 minutes) has passed since switching to the ON, When the relation (3) is established, the judgment is normal.
(RHb2-RHnew2) ≧ 5% …………………… (3)
This relation (3) indicates that the detected value of the humidity sensor 23 is properly lowered after a predetermined time has elapsed after the compressor 12 is operated.
[0024]
d) A second normality determination method will be described with reference to FIG.
Humidity when a predetermined time (for example, 5 minutes) has passed since the detected value of the humidity sensor 23 when the compressor 12 is switched from ON to OFF after being turned on for more than a predetermined time (for example, 5 minutes) is switched to RHb3, OFF. When the detection value of the sensor 23 is RHnew3, it is determined as normal (normal) when the following relationship (4) is satisfied.
(RHnew3-RHb3) ≧ 5% …………………… (4)
This relation (4) indicates that the detected value of the humidity sensor 23 is appropriately increased after the compressor 12 is stopped and a predetermined time has elapsed.
[0025]
Next, the abnormality determination method for the humidity sensor 23 described above will be described in accordance with a processing procedure (flow chart) of the ECU 7.
e) A first abnormality determination method (a flowchart is shown in FIG. 7).
In step 10, it is determined whether or not the compressor 12 has been switched from OFF to ON. When this determination result is NO, the timer is reset at step 30 via step 20. Thereafter, when it is determined in step 10 that the compressor 12 has been switched from OFF to ON, the detected value RHb of the humidity sensor 23 is read in step 40 and the timer is started in step 50.
[0026]
Subsequently, while it is determined in step 20 that the compressor 12 is ON, a timer is counted in step 60, and it is determined in step 70 whether or not the timer has expired. When the determination result is YES (terminal count) reads the detection value RHnew of the humidity sensor 23 in STEP80, perform error determination in Step90 (sensor function determination means).
In this error determination, a value obtained by subtracting the sensor value RHnew read in step 80 from the sensor value RHb read in step 40 is compared with a determination value (for example, 5%).
When the result of the error determination is YES, it is determined as “error” in step 100, the error count is incremented by +1, the normal count is cleared, and the process returns.
[0027]
f) Second abnormality determination method (shown in the flowchart in FIG. 8).
In step 11, it is determined whether or not the compressor 12 is in an ON state. When the determination result is NO, the timer 1 and the timer 2 are reset in step 41 via step 21 and step 31 (both determination results NO). The timer 1 is a timer that counts the time when the compressor 12 is ON, and the timer 2 is a timer that counts the time when the compressor 12 is OFF.
When returning to step 11 and determining that the compressor 12 is in the ON state (determination result YES), the timer 1 is counted in step 51 and the timer 2 is reset.
[0028]
Thereafter, when the determination result of step 11 is NO, it is determined in step 21 that the compressor 12 has been switched from ON to OFF, and the process proceeds to step 61.
In step 61, it is determined that the timer 1 has finished counting. If the determination result is YES, the detected value RHb1 of the humidity sensor 23 is read in step 71.
Subsequently, the process proceeds to step 31 via step 11 and step 21 (both determination result NO). Since the determination result of step 31 is YES (timer 1 has been counted), the process proceeds to step 81 and the timer 2 is counted.
[0029]
Subsequently, it is determined in step 91 that the timer 2 has finished counting. If the determination result is YES, the detected value RHnew1 of the humidity sensor 23 is read in step 101.
Subsequently, in step 111, an error determination of the humidity sensor 23 is performed. In this error determination, a value obtained by subtracting the sensor value RHb1 read in step 71 from the sensor value RHnew1 read in step 101 is compared with a determination value (for example, 5%).
When the result of the error determination is YES, it is determined as “error” in step 121, the error count is set to +1, the normal count is cleared, and the process returns.
[0030]
Next, the normality determination method of the humidity sensor 23 described above will be described according to the processing procedure (flow chart) of the ECU 7.
g) A first normality determination method (a flowchart is shown in FIG. 9).
In step 12, it is determined whether or not the compressor 12 has been switched from OFF to ON. When the determination result is NO, the timer is reset at step 32 via step 22. Thereafter, when it is determined in step 12 that the compressor 12 has been switched from OFF to ON, the detected value RHb2 of the humidity sensor 23 is read in step 42, and the timer is started in step 52.
[0031]
Subsequently, while the compressor 12 is determined to be in the ON state in step 22, the timer is counted in step 62, and it is determined whether or not the timer has expired in step 72. When the determination result is YES (end of counting), the detection value RHnew2 of the humidity sensor 23 is read in step 82, and normal determination is performed in step 92.
In this normal determination, a value obtained by subtracting the sensor value RHnew2 read in step 82 from the sensor value RHb2 read in step 42 is compared with a determination value (for example, 5%).
When the result of the error determination is YES, it is determined as “normal” in step 102, the normal count is incremented by +1, the error count is cleared, and the process returns.
[0032]
h) Second normality determination method (shown in the flowchart in FIG. 10).
In step 13, it is determined whether or not the compressor 12 is in an ON state. When the determination result is NO, the timer 1 and the timer 2 are reset in step 43 via step 23 and step 33 (both determination result NO). The timer 1 is a timer that counts the time when the compressor 12 is ON, and the timer 2 is a timer that counts the time when the compressor 12 is OFF.
Returning to step 13 and determining that the compressor 12 is in the ON state (determination result YES), the timer 1 is counted in step 53 and the timer 2 is reset.
[0033]
Thereafter, when the determination result in step 13 is NO, it is determined in step 23 that the compressor 12 has been switched from ON to OFF, and the process proceeds to step 63.
In step 63, it is determined whether the timer 1 has finished counting. If the determination result is YES, the detected value RHb3 of the humidity sensor 23 is read in step 73.
Subsequently, the process proceeds to step 33 via step 13 and step 23 (both determination result NO), and since the determination result of step 33 is YES (timer 1 has been counted), the process proceeds to step 83 and timer 2 is counted.
[0034]
Subsequently, it is determined in step 93 that the timer 2 has finished counting. If the determination result is YES, the detected value RHnew3 of the humidity sensor 23 is read in step 103.
Subsequently, normal determination of the humidity sensor 23 is performed in step 113. In this normal determination, a value obtained by subtracting the sensor value RHb3 read in step 73 from the sensor value RHnew3 read in step 103 is compared with a determination value (for example, 5%).
When the result of normal determination is YES, it is determined as “normal” in step 123, the normal count is set to +1, the error count is cleared, and the process returns.
[0035]
Next, an example of the air-conditioning control executed according to the determination result of the abnormality determination and normality determination of the humidity sensor 23 described above will be described based on the flowchart shown in FIG.
First, in step 1, the above-described abnormality determination and normality determination processing is executed.
Subsequently, the number of errors is determined by step 2 (sensor abnormality determination means of the present invention) . Here, when the number of errors is equal to or more than a predetermined number (for example, 5 times), the abnormality of the humidity sensor 23 is determined in step 3 and an error flag is set (ERRRFLG = 1).
[0036]
Further, when the judgment result of step2 is NO (less than the number of errors = 4 times) determines the normal number in step4 (sensor return judgment means). Here, when the number of normal times is equal to or greater than a predetermined number (for example, 5 times), the normality of the humidity sensor 23 is determined in step 5 and the error flag is reset (ERRRFLG = 0).
Subsequently, in step 6, the state of the error flag is determined. Here, when the error flag is set (determination result YES), air conditioning control that does not use the humidity sensor 23 is executed in step 7.
[0037]
On the other hand, when the determination result of step 6 is NO, that is, when the error flag is not set, air conditioning control using the humidity sensor 23 is executed in step 8.
In the air conditioning control using the humidity sensor 23, the target post-evaporation temperature TEO is determined based on the target blowing temperature TAO and the detected value of the humidity sensor 23, and the operation of the compressor 12 is controlled so that this TEO is obtained. It is to be. The air conditioning control without using the humidity sensor 23 is to determine the target post-evaporation temperature TEO from the target blowing temperature TAO and to control the operation of the compressor 12 so as to obtain this TEO.
[0038]
(Effect of this embodiment)
In this embodiment, as shown in the flowchart of FIG. 11, the state of the error flag is determined based on the number of errors and the number of normal times. Therefore, even if the error flag is set and the air conditioning control without using the humidity sensor 23 is executed, if the error flag is reset thereafter, the air conditioning control using the humidity sensor 23 is switched. This is because, for example, even when dust adheres to the humidity sensor 23 or the characteristics fluctuate due to electric noise or the like, and as a result, the abnormality of the humidity sensor 23 is confirmed, the factor of characteristic fluctuation is removed thereafter. If the humidity sensor 23 returns to normal, the error flag is reset, and air conditioning control using the humidity sensor 23 can be executed again.
[0039]
Further, in the control of this embodiment, the error flag is set when the number of errors exceeds a predetermined number (5 in this embodiment), so that the abnormality of the humidity sensor 23 can be determined more accurately. Similarly, when performing normal determination, the error flag is reset when the number of normal times exceeds a predetermined number (5 in this embodiment), so that the humidity sensor 23 can be determined normally more accurately. . Thereby, although the humidity sensor 23 is normal, an erroneous determination that is determined to be abnormal can be prevented.
[0040]
(Second embodiment)
In the abnormality determination and normality determination of the humidity sensor 23 described in the first embodiment, it is difficult to detect the accurate humidity in the passenger compartment when the window glass of the vehicle is open. Therefore, in this embodiment, abnormality determination and normality determination of the humidity sensor 23 are performed only when the window glass is closed. Therefore, when it is determined that the humidity sensor 23 is normal (error flag = 0), the air conditioning control using the humidity sensor 23 is executed with the window glass closed.
[0041]
The open / closed state of the window glass can be determined by the following methods (1) to (5).
(1) Judgment is made using a window glass sensor capable of detecting the open / closed state of the window glass.
(2) Judgment is made by inputting the signal of the open / close switch of the power window. Specifically, as shown in FIG. 12, the signal line 34 is taken out from the electrical wiring 33 that connects the open and closed contacts of the open / close switch 30 and the drive circuit 32 of the motor 31, and is connected to the ECU 7. The switch signal is input to the ECU 7. The ECU 7 has the function of the window glass determination means of the present invention, measures the time when the open contact is pressed and the time when the closed contact is pressed based on the switch signal, and determines the time when the open contact is pressed. If it is longer, it is determined that the window glass is open.
[0042]
(3) Determine by inputting the voltage between the motor terminals of the power window. Specifically, as shown in FIG. 13, the signal line 35 is taken out from both terminals A and B of the motor 31 and connected to the ECU 7. Here, the potentials of the terminal A and the terminal B are compared, and the rotation direction of the motor 31 can be detected depending on which potential is higher, and whether the window glass is closed or open depending on the rotation direction of the motor 31. Can be determined.
[0043]
(4) If air conditioning is performed with the window glass closed, the room temperature approaches the set temperature after a certain period of time has elapsed since the start of air conditioning. Therefore, when the set temperature is Tset and the vehicle interior temperature after a certain time has elapsed since the start of air conditioning is Tr1, it can be determined that the window glass is closed when the following relationship holds.
Tset−judgment value ≦ Tr1 ≦ Tset + judgment value
{Circle around (5)} When the time during which the window glass is open has elapsed, the cabin temperature and the outside air temperature become substantially the same. Therefore, when the current vehicle interior temperature is Tr and the current outside air temperature is Tam, it can be determined that the window glass is open when the following relationship holds for a certain period of time.
Tam−judgment value ≦ Tr ≦ Tam + judgment value
(Modification)
In addition to the method described in the first embodiment, the abnormality determination method for the humidity sensor 23 can be performed by the following method. That is, when the effective detection range of the humidity sensor 23 is 10 to 90%, for example, a value outside the effective detection range (10% or less, or 90% or more) is detected for a certain period of time (for example, 5 minutes). An error can be determined as a failure due to disconnection or short circuit of the humidity sensor 23.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a vehicle air conditioner.
FIG. 2 is a front view of an A / C operation panel.
FIG. 3 is an explanatory diagram of a first abnormality determination method for a humidity sensor.
FIG. 4 is an explanatory diagram of a second abnormality determination method for a humidity sensor.
FIG. 5 is an explanatory diagram of a first normality determination method of a humidity sensor.
FIG. 6 is an explanatory diagram of a second normality determination method of the humidity sensor.
FIG. 7 is a flowchart showing a processing procedure of a first abnormality determination method.
FIG. 8 is a flowchart showing a processing procedure of a second abnormality determination method.
FIG. 9 is a flowchart showing a processing procedure of a first normality determination method.
FIG. 10 is a flowchart showing a processing procedure of a second normality determining method.
FIG. 11 is a flowchart showing a processing procedure of air conditioning control.
FIG. 12 is a system diagram related to window glass open / close determination.
FIG. 13 is a system diagram related to open / close determination of a window glass.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vehicle air conditioner 4 Refrigerating cycle 7 ECU (Sensor abnormality determination means, sensor return determination means, sensor function determination means, compressor control means, window glass determination means)
12 Compressor (refrigerant compressor)
23 Humidity sensor 30 Open / close switch 31 Motor

Claims (2)

A refrigeration cycle having a refrigerant compressor;
A humidity sensor that detects the humidity in the passenger compartment;
Sensor abnormality determining means for determining whether or not the humidity sensor has an abnormality based on on / off switching of the refrigerant compressor, and the sensor abnormality determining means is provided only when the vehicle window glass is closed. In a vehicle air conditioner that performs abnormality determination of a humidity sensor,
The window glass judging means comprises a window glass judging means for judging the open / closed state of the window glass. The window glass judging means sets the vehicle interior temperature Tr1 after a certain period of time from the start of air conditioning in the vehicle interior and the set temperature in the vehicle interior When Tset
Tset−judgment value ≦ Tr1 ≦ Tset + judgment value …… (1)
When the relationship of (1) is established, it is determined that the window glass is closed. A refrigeration cycle having a refrigerant compressor;
A humidity sensor that detects the humidity in the passenger compartment;
Sensor abnormality determining means for determining whether or not the humidity sensor has an abnormality based on on / off switching of the refrigerant compressor, and the sensor abnormality determining means is provided only when the vehicle window glass is closed. In a vehicle air conditioner that performs abnormality determination of a humidity sensor,
The window glass determination means for determining the open / closed state of the window glass, the window glass determination means, when the current vehicle interior temperature is Tr, and the current outside air temperature is Tam,
Tam−judgment value ≦ Tr ≦ Tam + judgment value (2)
A vehicle air conditioner characterized by determining that the window glass is open when the relationship of (2) above is established continuously for a certain period of time.

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