JPS6076416A - Air conditioner for automobile - Google Patents

Abstract

PURPOSE:To improve digital conversion resolution in an air conditioner with a digital conversion means and a failure detecting means by providing a failure detecting means for generating the output signal with specified voltage higher than that for catching capability of a temperature signal digital conversion means. CONSTITUTION:A control section 2 is provided with a voltage dividing resistors 302, 303 and a comparator 304 for detecting sensor failures. In this constitution, respective signal voltage VS, VR, VT, VC of set temperature 31, room temperature 170, adjusting door 142 and exhaust temperature 160 are digitized by A/D converter 21 to be sent to the input of a microcomputer 22. If the signal voltage is then less than 0.5V due to short-circuit or the like at that time the failure signal is generated. When the signal voltage exceeds the upper limit 4.5V which can be converted digitally and higher than the divided voltage 4.95V of resistors 302, 303, the comparator 304 generates the failure signal output to a microcomputer 22. Thus, failures at the low voltage side as well as the high voltage side can be detected to improve the resolution of digital conversion amount.

Description

[Detailed description of the invention]

[Field of Application of the Invention] The present invention relates to an air conditioner for an automobile, and relates to a failure detection method suitable for detecting a failure of a sensor. [Background of the Invention] The conventional senna failure detection method involves converting the senna signal voltage, which corresponds to a temperature of several degrees, into a digital quantity.
It was determined that the sensor signal line was disconnected or short-circuited when a voltage was input that corresponded to a temperature that was normally unbearable. However, with this method, it is necessary to input voltage that exceeds the voltage range that corresponds to the temperature required for temperature control.・When converting to a digital amount using the same number of divisions, only the voltage range that corresponds to the temperature range required for temperature control is input. Compared to when converting, there are problems such as the temperature per division is larger, the resolution becomes rougher, the number of divisions needs to be increased to obtain the same resolution, and the conversion element becomes complicated. There were drawbacks. [Object of the Invention] An object of the present invention is to provide an air conditioner with high resolution of digital conversion by reducing the signal voltage change in one digital quantity division. [Summary of the Invention] The present invention: converts a first signal voltage range corresponding to a temperature necessary for temperature control into a digital quantity, and further exceeds a second predetermined voltage range exceeding the voltage range. A means for detecting a senna signal voltage corresponding to an impossible temperature is provided, and the output signal is input into a microcomputer to detect a failure. Here, the temperature corresponding to the voltage between the first voltage range and the second voltage range does not need to be distinguished from the temperature corresponding to the end of the first voltage range for control purposes, but may be different. It's temperature. [Embodiment of the Invention] An embodiment of the present invention will be explained with reference to the drawings. FIG. 1 is an overall configuration diagram showing an embodiment of an air conditioner for an automobile according to the present invention. The automotive air conditioner of this embodiment includes a heat exchange section 1 that sucks air from inside and outside the vehicle, heats or cools it, and blows it out into the vehicle interior to be air-conditioned, and each device of this heat exchange section 1 is connected electrically. It consists of a control unit 2 that controls the operation, an operation unit 3 that inputs the start/stop of this device and desired set temperature to the control unit 2, and sensors that input vehicle room temperature signals and equipment status signals of the heat exchange unit 10 to the control unit 2. ing. The control unit 1 is provided with an outside air suction port 101 for sucking air from outside the vehicle interior, an inside air suction port 102 for sucking air inside the vehicle interior, and a suction port door 111 for controlling the opening and closing of these suction ports. This suction port door 111 is equipped with a two-stage action negative pressure actuator 11.
2 and a return spring 113 to control the position to 3. That is, each negative pressure working chamber of the negative pressure actuator 112 is connected to a negative pressure source such as a negative pressure pump via the solenoid valves 114 and 115, and the suction port door 111 is connected to both the solenoid valves 114 and 115. When neither of the solenoid valves 114 and 115 is energized, the force of the return spring 113 closes the inside air intake port 102 and brings in outside air. When both the solenoid valves 114 and 115 are energized, the negative Due to the pressure, the outside air suction port 101 is closed, and the state of inside air suction is established. Furthermore, when the solenoid valve 114 is energized but the solenoid valve 115 is not energized, negative pressure acts only on one negative pressure working chamber of the negative pressure actuator 112, so the suction port door 111 stops at an intermediate position between the above states and sucks outside air. Mouth 101. Both the inside air suction ports 102 are opened and the inside and outside air is being sucked. The heat exchange unit case 100 is provided with a blower 121 that sucks air from the suction port and sends it to the heat exchange unit, which will be described later. The air volume by this blower 121 is controlled by the control unit 2.
motor 122 by driver 123 controlled by
It is controlled by controlling the applied voltage supplied to. An evaporator 131 is provided downstream of the blower 121, and this evaporator 131 constitutes a compression refrigeration cycle with a compressor 132, a condenser (not shown), an expansion valve 133, etc., and cools the air passing through it. It has become a means. The compressor 132 is driven by the automobile engine via a magnetic latch 132a, and the electromagnetic clutch 132ae is energized or de-energized by a compressor relay 132b whose driving or non-driving is controlled by a control signal from the control unit 20. This is done by Furthermore, a heater core 141 serving as a heating means is provided downstream of the evaporator 131, and the engine cooling water (warm water) of the automobile is circulated through this heater core 141 to heat the air passing through this heater core 141. A temperature control door 142 is provided to control the amount of heating by increasing or decreasing the amount of air passing through the heater core 141. The temperature control door 142 is rotated by a return spring 144 and a negative pressure actuator 143 connected to the negative pressure source through solenoid valves 145 and 146. Solenoid valve 145.146
When both are not energized. The negative pressure operating chamber of the negative pressure actuator 143 is connected to a solenoid valve 145.
146 to the atmosphere, no negative pressure acts, and the return spring 144 causes the temperature control door 142 to rotate in the direction in which θ decreases in FIG. 1. In other words, the amount of air passing through the heater core 141 is increased. I will let you do it. When the solenoid valve 145 is energized and the solenoid valve 146 is not energized, the negative pressure operating chamber of the negative pressure actuator 141 is connected to the solenoid valve 1.
It is connected to a negative pressure source through 46 and 145, and negative pressure acts thereon. As a result, the temperature control door 142
4 and rotates in the direction in which θ increases. That is, it operates to reduce the amount of air passing through the heater core 141. A potentiometer 147 that operates in conjunction with the temperature control door 142 inputs a position signal corresponding to the position of the temperature control door 144 to the control unit 2 in the form of a voltage (1) and (7) rises as θ increases. Also, although specific processing will be described later, the difference lΔV between the target position and the detected position? If + is large for a predetermined time, it is determined that there is a failure. Although the details will be described later, the temperature control door 142 is feedback-controlled with the above configuration, and the amount of air passing through the heater core 141 is from 0 (maximum θ) to 100% ( θ
is controlled to O). Moreover, the air that does not pass through the heater core 141 passes through the bypass 103 provided in parallel to the heater air 141, passes through the heater core 141, mixes with the heated air, and is blown into the vehicle interior. The air that has passed through the evaporator 131 and the heater core 141 or the bypass 103 enters the vehicle interior through the upper outlet 104 and the lower outlet 10.
5 or into the vehicle interior from the differential air outlet 106 to the windshield. A mode door 151 is provided for switching the air outlet into the vehicle interior, and this mode door 151
Similarly to the inlet door 111, it is controlled to three positions by a two-stage action negative pressure actuator 152. The two negative pressure working chambers of the negative pressure actuator 152 are respectively connected to the negative pressure source via solenoid valves 154 and 155, and the solenoid valve 1
When both 54 and 155 are not energized, the return spring 153 closes the upper outlet 104 and the air is blown out from the lower outlet 105. Also, solenoid valve 1
When both 54 and 155 are energized, a negative pressure source is connected to both negative pressure working chambers of the negative pressure actuator 152, the mode door 151 closes the lower outlet 105, and the air is blown out from the upper outlet 104. . When the solenoid valve 154 is energized and the solenoid valve 155 is not energized, only one negative pressure working chamber of the negative pressure actuator 152 is connected to the negative pressure source, so the mode door 151 is in the intermediate position, upper position, in the above state. Air outlet 104. Both lower air outlets 105 are in an open state, and the air is blown out from both secondary outlets. This is a so-called pi-level state. The differential air outlet 106 is opened and closed by a differential door 156 (usually configured so that a small amount of air is discharged even when the differential door is closed). The differential door 156 is operated by a negative pressure actuator 157 connected to the negative pressure source via a solenoid valve 159 and a return spring 158. When the electromagnetic valve 159 is energized, negative pressure acts on the negative pressure actuator 157 and the differential door 156 opens against the return spring 158, and when the electromagnetic valve 159 is not energized, the differential door 156 is closed by the return spring 158. Immediately downstream of the evaporator 131, a discharge temperature sensor 160 is provided using a thermistor or the like to detect the temperature of the air immediately after passing through the evaporator 131, that is, the discharge temperature Ta.
is input to the control unit 2 in the form of voltage VcO. A vehicle room temperature sensor 170 is installed at an appropriate position in the vehicle interior to detect the vehicle interior temperature T.
i is input to the control unit 2 in the form of voltage VB. By the way, the Ta, Ta temperature sensor signal with the characteristics shown in FIG. 11 is 0.5 (V) to 45 (V))
('c) to 80CC) is converted into a digital quantity by the A/D conversion circuit 21 and input. For the low voltage side due to short circuits, etc., the voltage required for fault detection can be input at 80℃, but for the high voltage side due to disconnections, etc., it is insufficient at -17℃, and the voltage corresponding to -50cc) (4.95V). ) is provided as a reference for detecting sensor failure. The control unit 2 includes the sensors, an A/D converter 21 that converts analog signals from the operating unit 3 into digital signals, a comparator 304 for detecting sensor failure, and signals from the A/D converter 21 and the operating unit 3. The heat exchange section 1 is comprised of a microcomputer 22 that processes digital signals, and an interface circuit 23 that controls each device in the heat exchanger 1 based on the output signals of the microcomputer 22. This interface circuit 23 connects the solenoid valves 114, 115, 145, 146, 154° 155.1 of the heat exchanger 1.
59. Transistors 231 to 238 as switch elements that control the compressor relay 132b. It is comprised of a D/A converter 239 for supplying an analog voltage to the driver 123 that supplies power to the motor 122. The operation unit 3 includes an air conditioner switch for starting and stopping the device, and a temperature setting device 31 for setting the desired temperature in the vehicle interior. Dehumidification switch 32 for manually dehumidifying the interior of the vehicle. A differential switch 33 for blowing air from the differential outlet 106 to the windshield and a malfunction indicator lamp 3
05 etc. The desired temperature of the vehicle interior set by the temperature setting device (target set temperature 11m,
l F is also input to the control unit 2 in the form of voltage levels. The operation of the automatic air conditioner according to this embodiment having the above configuration will be explained. FIGS. 2 and 3 are flowcharts of the operation of the control section 2. FIG. The numbers in parentheses in the figure are step numbers indicating the order of the flow. As shown in the figure, the operation of one device is step (201).
) to (203) initialization, step (204)
- (217) is repeated infinite times, and during the processing of this main routine, the cycle is several hundredths of one (1/100 in the embodiment) compared to one cycle of the main routine (about 1 second in the embodiment). seconds) and steps (220) to (227
). First, when this device is activated by the air conditioner switch, I10 data of the control unit 20 and microcomputer 22 is set to a predetermined initial value (201), and the RAM of the microcomputer 22 is cleared (202). Next, the voltage V of the potentiometer 147 corresponding to the position of the temperature control door 142 (θ dew 0)! is converted into a digital quantity [vte] by the A/D converter 21 and read as the initial value of the door reference position. Note that this door reference position signal is monitored and updated by the interrupt routine (224). Next, move on to the main routine. Voltage V111 corresponding to the target set temperature TII set by the operation unit 3 Voltage VR% corresponding to the cabin temperature TR Voltage Vcb corresponding to the discharge air temperature Tc The conversion circuit shown in FIG. 6 and the process shown in FIG. Then, each digital value [:V
g], (Va], [Vc:] and input to the microcomputer 22 (204) Input the voltage ■8 corresponding to Ts [zo4-o)), 'I'R
, 'r'a sensor 160° and 170 respectively [
204-2)) - Converted into a digital quantity by the A/D converter 21 and inputted ([:204-3]). It is difficult to determine whether the signal voltage is low due to a short circuit, etc. [:204-4])
- If it is low, it is assumed that there is a short circuit.・The corresponding failure flag is set in the memory of the microcontroller 22 (1
:204-5:l). Furthermore, when the target is the inside temperature (C204-6)), it is replaced with a voltage equivalent to room temperature so that it can be used as a manual air conditioner by raising or lowering the set temperature ((204-71). When the target is the temperature immediately after the evaporator, , to prevent the evaporator from freezing, replace it with a voltage corresponding to a low temperature ([:204-83).When the signal voltage exceeds the upper limit that can be converted into a digital quantity ((2
04-9) ), 4.95CV created by the divided voltage of resistors 302 and 303] It is necessary to judge whether it exceeds the reference voltage for failure detection [204-10)) - If it exceeds, it is regarded as a failure such as a disconnection. , set the corresponding failure flag in the memory of microcomputer z2 [204-11)) - move the process to step [204-6] ([204-12)
), reading of the voltage VTE corresponding to the position of the temperature control door 142 is performed by a timer interrupt, and will be described later. [:Lt),
[:Vo) is converted into a digital value 1:Tm ], (Tc) corresponding to the cabin temperature and exhaust air temperature using a conversion map stored in the ROM of the microcomputer 22.
205). (Va') is converted into a digital value ['rs] of the target set temperature using a first-order conversion formula (206). The deviation [ΔT)-CTs:l-[Tn] between the target temperature setting [TII] and the cabin temperature [T8] is found (2
07). The deviation [ΔT] is used to detect failures in the cooler and heater functions. The heater function, cooler function, and temperature control door are all working properly. When it is functioning, it is provided in the memory of the microcomputer 22, which counts by a time interrupt, which will be described later. Each failure detection counter is cleared by the failure diagnosis process (218) of the main program. When the abnormal state continues and the counter is no longer cleared, the counter reaches a predetermined value, the corresponding function is deemed to be faulty, and a corresponding fault flag is set in the memory in the microcomputer 22. The failure diagnosis process (218) shown in FIG. 9 will be explained below. It is difficult to judge whether the absolute value of the difference between the temperature control door target voltage and the actually detected voltage is less than a predetermined value (Δθ) [218-
t)) - During normal operation, the counter for temperature door failure detection is cleared ([218-2]). It is difficult to judge whether the difference between the target set temperature and the inside air temperature is less than the predetermined value (ΔT) [2
18-3]), during normal operation, clears the heater failure detection counter ([:218-4:]). Control signal (X)
Determine whether it is a cooler region (X<O) or a heater region (X>O)
), clear the cooler failure detection counter (
218-8))・On the other hand・When in the Ku2 area, furthermore,
It is determined whether the difference between the target set temperature and the internal air temperature is equal to or greater than a predetermined value (ΔT/), and when it is normal. Clear the counter for cooler failure detection ([218-
7)). In the failure display process ([218-9)): If any failure detection flag is set in the memory of the microcomputer 22, the failure indication lamp on the operation panel is turned on to notify the driver. The counting of the failure detection counter is performed in the failure detection counter process (228) shown in FIG. 10 during the time interrupt process that is executed at regular intervals. Count up the temperature control door failure detection counter ("228-1]). When the temperature control door failure detection counter reaches a number corresponding to the elapse of a predetermined time (for example, 10 seconds) (1:228-z)) - Set the temperature control door failure detection flag in the memory of the microcontroller 22 [228-3]). Count up the heater failure detection counter [:228-4]), and set the heater failure detection counter for a predetermined time (228-3)). For example, when the number corresponds to the elapse of 20 minutes (1:228-5:l)-set the heater failure detection flag in the memory of the microcontroller 22 ((228
-61). Count up the cooler failure detection counter [228-7)). The cooler failure detection counter is set for a predetermined period of time (for example, 20 minutes)
When the number corresponds to the elapsed time ([228-8)), the cooler failure detection flag is set in the memory of the microcomputer 22 CC22B-91). Next, [:X]-k(:ΔT]+!-I[Δ'l')d
tτ A long PI operation is performed. First, the integral term in the above equation is calculated by adding the temperature deviation [ΔT] every predetermined time specified by the timer process (226) of the interrupt routine (208), and further, this integral term is k(Δ
By adding T), the control signal [X] can be determined (2
09). In the improvement equation, τ is a constant determined by the control system. Also, when the dehumidification operation is performed by the dehumidification switch 32, the temporary correction value [
ΔX] is added to obtain a corrected value. This dehumidification operation will be described later. The control signal [X] determined in this way must be of an amount commensurate with the amount of heat required by the cabin heat load in the process of controlling the cabin temperature Tm to the target setting temperature T-, and in this example, k>0τ 〉0
Therefore, when [X]〉0 is selected, the heating power is increased, and the larger the [X] value is, the greater the heating power is.When [X] is 0, the cooling power is increased, and the larger the [-X] value is, the greater the cooling power is. means you need it. The operation of this air conditioner based on the value of this control signal [X] will be explained with reference to FIG. 4. Figure 4 shows the horizontal axis control signal [X]
2 shows the operating state of the heat exchanger 1 with respect to FIG. First, the temperature control door target voltage (V!
o:l is calculated (210). This target voltage CVra] is a linear expression regarding [X], and (X) is

[0] satisfies the following two points: (Vyo] = [Vtt:] - a predetermined positive value of [X] [X3], (Vt.) = [vte snow].Here, (V 1) is a state in which the temperature control door 142 closes the passage to the heater core 141 (θ
J)-[V-z:I is the voltage of the potentiometer 147 when the passage to the heater core 141 is completely opened (θ-0). Next, in the 1st interrupt processing routine, the voltage of the potentiometer 147 is read as the position signal of the temperature control door 142, and
/D converter 21 outputs the sidigital value [V? ] (222). Next, the position control of the temperature control door 142 is performed by comparing the target voltage [:VTO] and [Vv') (223
). First, [ΔVy) - [Vyo) [V? : l to a predetermined value [ΔV? p)>[ΔVy] for O>
[ΔVrp:l? "1'-CΔVT)<[ΔV?
The control signal [T!] which becomes °O'' at [P] and [-ΔV?
p:]<[ΔVT)<[ΔVTP)"1'Create a control signal [T2] that becomes "0' in a range other than the above. When the control signals CT3]' and (Tz) are 1°, the switching elements 233 and 234 are turned on and the solenoid valves 145 and 146 are energized, and when they are 0, they are not energized. Energization, [ΔV?:l>
At (ΔV?P), the temperature control door 142 is rotated in the direction in which θ increases, and at [ΔV■], the temperature control door 142
is rotated in the direction in which θ decreases. [−ΔVyp]≦[
ΔVT)≦[Δ■? ν], the temperature control door 142 is in a stationary state, and at this time the temperature control door position θ is determined by the control signal [X
) is located at a position corresponding to the target voltage (V2O) corresponding to . Returning to step (214) of the main routine, exhalation Tc
The target temperature [Too) of is then requested by [X] for the negative value [X3] of the predetermined CX).
≦[X2], C'I'ao) is the lowest possible value CTat) at which the evaporator surface is just before freezing (in this example, 25'c
), and in the range [X]≧[X2], [X″1-(X
s:) is the above-mentioned (Tot), and (X:l - [0] is the predetermined value [Tcs:l (in this example, 25°C)), which is the value requested by the linear equation connecting the two points. The vicinity of [Xl-[:0] is a region where the cabin heat load does not require heating power or cooling power.#)1 Outside air temperature T. is close to the target set temperature T11. In this region, there is almost no need to operate the cooling means (Te3:l
It is set to medium [T■]. In the next step (215), the target discharge temperature [Tco
] and discharge temperature [Tc:l are compared, and the temperature difference [ΔT
c ) = (Tco:] (Tc ) is calculated, and this [
A compressor operation signal [C] is generated based on the value of ΔTc). That is, [ΔTc)>[0), [C] is “0°, [Δ
'rc)<Co), [C] becomes 11°. When the compressor control signal [C] is '1'', the switching element 235 is turned on at step (217) and the compressor relay 132b is energized.
a is excited, the compressor 132 operates, and the evaporator 131
The air passing through is cooled and the discharge temperature Tc decreases. Exhalation temperature T
If a decreases, [Δ'rc)≧

[0] Tona Power [
C]-@o'% Then the last step of the routine (
217), the compressor 132 becomes inactive. By repeating the operation and non-operation of the compressor 132 in this way, the discharge temperature Ta is maintained close to the target temperature CToo) determined by the control signal [X]. However, as mentioned above, C
In the range of X:+>O, the cabin heat load requires heating power, and the target set temperature Tg > the cabin outside air temperature To, the other Ta6
>Ts in Tag Since the suction door 111 sucks in air outside the vehicle interior, the temperature of the air sent to the evaporator 131 is close to the outside air temperature To. Therefore, even if the cooling means operates [ΔT
c)>O, the deshico/presser 132 does not operate. The blower air volume A is approximately proportional to the voltage Vy supplied to the motor 122. The voltage supplied to this motor is controlled as follows. First, A target voltage (Vy) is determined corresponding to the control signal [''X]. For a predetermined negative value CXtl of [X] - positive value [X4], [X]≦[Xl
] and [X]> [X4] Te maximum value 1: Vyt] (ti12V in this embodiment). The negative value [X2) minus the positive value [X8] (CVy) is set to the minimum value [VF2:] (4 V in this embodiment). [Xt ) ([X]51:X2] In the range [X1]
becomes [VP1], [XS] becomes [:Vyg:l]2
The linear equation connecting the points is [:VF lf:determined, [:Xs]
<[:X]<CX4]C) In the range (Xa], CVy)
, (X4'), [Vy] is determined from a linear equation connecting two points that become [:VF1] (216). The target value [VP] obtained above is converted into an analog voltage VFI+ by the D/A converter 329 of the interface circuit 32 in step (217), and is applied to the motor 122 by the driver 123 controlled by this voltage Vyg. The voltage ■v is controlled and driven. Depending on the value of the control signal [X], when it is less than [X1], VF becomes maximum, that is, the blower air volume A becomes the maximum AM value X. [Xt: Between l and [X2], the blower air volume is maximum k
decreases almost linearly from whx to minimum AMIN, [X
Between [2] and [X3], the blower air volume is kept at the minimum A old N, and between [XS) and [X4], the blower air volume increases linearly from the minimum AMIN to the maximum AMAX, and [X
4] With the above steps, the blower air volume is continuously controlled so as to reach the maximum AM I. The above-described operation of the external suction rod door 111. mode door 15
1 is also controlled by the value of the control signal [X]. [x]≦[
Control signal [:11], (X]≦[:XI:1 becomes “1” [X]>[
Create a control signal [X2] that becomes °0° with [Xfi] (21
1). In addition, [X6] is a negative value and [Xs ) < (Xs ]
<[:Xs':]. When the control signals (Is) and (Is) are 01'', the switching element 231.
232 turns on, energizes the solenoid valves 114 and 115, and becomes "0".
When ゛, the solenoid valve is not energized. When control signal [X]≦[XI], as described above, l:
11 ], [:Ii ”] Both appear as “1#” Solenoid valve 1
14 and 115 are both energized, and the actuator 112 brings the suction door 111 into a state of sucking inside air. [X]〉

When [0], both (L) and [:I*]”
0" diameter suction door 111 has a return spring 113
It is pulled by the air and enters a state where outside air is sucked in. In [X,]≦CX]<Co), [Work 1] is “1”. [03<CXe]<03<CXe]<CXt]<l:Xs] CXa], CXt] are predetermined.
Control signals [O1] and [X] that become °0'' at l:X7]
A control signal [02] is created (212) that becomes °1" at <[X6] and "0" at [X]>[X6]. The mode door is 151 is driven as follows at step (217'J). When (X)<CXs), both COt] and (Ox) are "1 degree", and switch elements 236 and 237 are both turned on, and the solenoid valve is turned on. 154 and 155 are both energized, and the mode door 151 is brought into an upward blowing state by the actuator 152. When [:X]>[:X7], (IC)t:1.[
:02':]Both are 0°, solenoid valves 236 and 23
7 is not energized, and the mode door 151 is brought into a downward blowing state by the return spring 153. [Xe] If [X]≦[X7], [Ot] is “
1", [0!: Since I becomes "0", the solenoid valve 154 is energized and the solenoid valve 155 is not energized, so the mode door 151 is in the intermediate position and enters the upper and lower blowout state. According to an embodiment of the present invention For example, failures can be detected early, the compressor etc. can be protected, and the air conditioner can be used like a manual air conditioner until repairs are made. [Effects of the Invention] According to the present invention, sensor signals can be This has the effect that the voltage range for converting into digital quantities can be within the range necessary for control, and the resolution of digital quantity conversion can be improved.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of the embodiment, Fig. 2 is a main routine flowchart of the control section of the embodiment, Fig. 3 is a flowchart of the training routine, and Fig. 4 is an explanation of the operation of the heat exchange section of the embodiment. Figure 5 is a diagram of its heat dissipation characteristics, and Figure 6 is a diagram of its heat radiation characteristics.
7 is a detailed flowchart of the senna voltage A/D conversion section of FIG. 2, and FIG. 8 is a circuit diagram of the temperature sensor voltage detection section of the figure.
FIG. 9 is a detailed flowchart of the failure detection counter process shown in FIG. 3, and FIG. 10 is an explanatory diagram of the failure detection counter process. 1... Heat exchange section, 21... Control section, 3... Operation section,
22... Microcomputer, 31... Temperature setting switch, 32... Dehumidification switch, 33... Differential switch, 111... Suction port door, 121... Prower 1131... Evaporator, 133...Compressor,
141... Heater core% 142... Temperature control door. Agent Patent Attorney Akio Takahashi 94- '82 Group 3rd 4th grade 5th grade 6th grade 8th grade voltage [°C]

Claims (1)

[Claims] 1. Cooling means, heating means, temperature detection means, means for converting the signal voltage of the detection means into a digital quantity, and failure detection means for the detection means, and the amount of heat received by the air passing through the cooling and heating means. In an air conditioner for an automobile that automatically controls the inside of a vehicle to a target set temperature by controlling the temperature using a microcomputer, a first method that can be detected by the means for converting a signal voltage of a temperature detecting means into a digital quantity; The failure detection means is configured such that when a voltage further exceeding a second range exceeding the voltage range is inputted, means is provided to output a specific signal, and the microcontroller takes in the signal and detects a failure. Automotive air conditioner.