JPH04110220A - Automotive air conditioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to failure diagnosis of a variable condensing capacity device provided in a condenser in an air conditioner for an automobile.

[Conventional technology]

As described in Japanese Unexamined Patent Publication No. 2-31912, the conventional device changes the cooling capacity by switching the control valve coil supply current, which is the output to the variable capacity device of the compressor, by operating a switch on the operation panel. It has a failure diagnosis function for the variable capacity device, such as making a judgment based on temperature changes in the bath air.

Furthermore, as described in Japanese Patent Application Laid-Open No. 2-24220, a bypass line with a pressure regulating valve that opens when the refrigerant pressure in the condenser falls below a predetermined value is provided in the condenser line to maintain the condensing pressure at a constant value. I try to keep it above that.

[Problem to be solved by the invention]

However, in the technique described in Japanese Patent Application Laid-Open No. 2-24220, the pressure regulating valve is mechanical, and no consideration is given to failure diagnosis.

Further, in the technology described in Japanese Patent Application Laid-Open No. 2-31912, the cooling cycle control device is only the capacity variable device,
No consideration was given to the case where a plurality of condensing capacity variable devices are added.

An object of the present invention is to provide an air conditioner for an automobile that has a plurality of control devices including the variable condensing capacity device and is capable of diagnosing a failure of a cooling cycle.

[Means to solve the problem]

In order to achieve the above object, the first invention of the present invention
A cooling cycle having a condenser equipped with a variable condensing capacity device and a compressor equipped with a variable discharge capacity device, an instruction means for a diagnostic function that outputs a control signal to the variable discharge capacity device in a predetermined pattern, and the instruction and a diagnostic control means for controlling the variable discharge volume device when a diagnostic function is selected by the means, wherein the diagnostic control means controls the condensation according to the output of the instruction means. The device is characterized in that it is a means for controlling a capacity variable device and outputting an instruction for a smaller capacity side to the discharge capacity variable device when instructing the condensing capacity variable device to reduce the condensing capacity. .

Further, a second aspect of the present invention provides an air conditioner for an automobile equipped with a cooling cycle having a compressor equipped with a variable condensing capacity device, in which the thermal load of the automobile is detected. a diagnostic function instruction means for outputting a control signal to the variable condensing capacity device in a predetermined pattern; and a diagnostic function for controlling the variable condensing capacity device when a diagnostic function is selected by the indicating device. and a control means for diagnosis, the diagnostic control means having means for prohibiting output of a capacity reduction control signal to the variable condensing capacity device when the heat load detection means detects a heat load of a predetermined value or more. It is characterized by:

Further, a third aspect of the present invention provides a cooling cycle having a condenser equipped with a variable condensing capacity device and a compressor equipped with a variable discharge capacity device, and the variable discharge capacity device. An air conditioner for an automobile, comprising: a diagnostic function instruction means for outputting a control signal to a vehicle in a predetermined pattern; and a diagnostic control means for controlling the discharge volume variable device when the diagnosis function is selected by the instruction means. A heat load detecting means for detecting a heat load of the automobile is provided, and the diagnostic control means controls the condensing capacity variable device according to the output of the indicating means, and the heat load detecting means controls the condensing capacity variable device to a predetermined value. The present invention is characterized by having means for outputting a capacity reduction control signal to the condensing capacity variable device when the following heat load is detected.

Furthermore, a fourth aspect of the present invention is that in the second or third aspect, the heat load detection means detects the temperature of the outside air.

[Effect]

According to the first invention, whether or not the variable condensing capacity device of the condenser is functioning correctly can be determined based on the fact that when the condensing capacity is reduced, the indicated value of the pressure gauge provided on the discharge side piping of the compressor increases. It can be determined by At this time, the variable discharge capacity device is set to the small capacity side, so the condensing pressure becomes high.
Even in environments with high heat loads, failure diagnosis of the variable condensing capacity device can be performed without activating the high voltage protection switch.

Further, in the second invention, when the heat load detection means detects a predetermined value or more, a means for prohibiting the output of the capacity reduction control signal to the condensing capacity variable device is provided, so that the condensing capacity can be reduced in an environment where the heat load of the condenser is large. By reducing the capacity of the container, it is possible to prevent the condensing pressure from becoming too high and damaging the cooling cycle parts.

Further, in the third invention, since the means for outputting a capacity reduction control signal to the condensing capacity variable device when the thermal load detecting unit detects a predetermined value or less is provided, the discharge pressure required for operating the discharge capacity variable unit is provided. However, a high value can be obtained even under a low heat load, making it possible to diagnose the failure of the variable discharge capacity device.

Furthermore, in the fourth invention, since the heat load detection means is an outside air temperature detection means, the outside air temperature detection means provided for air conditioning can be used.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 is a block diagram of an air conditioner for an automobile, which is an embodiment of the present invention. The air conditioner is.

An intake blower unit 1 sucks in air, a cooling unit 2 cools the air, a heater unit 3 heats the air appropriately, and then blows it out into a passenger compartment 4.

The intake blower unit 1 includes an intake door 7 that switches between an inside air intake port 5 and an outside air intake port 6, and
It consists of a blower 8 that sends air. Depending on the position of the intake door 7, the intake of air can be "outside air", "inside air", or "inside air" as shown in the figure.
There are three states: "inside/outside air".

The cooling unit 2 includes an evaporator 9 that is an evaporator.
, an expansion valve 1o, and an air temperature sensor 11 provided downstream of the evaporator 9. The evaporator 9, together with an expansion valve 10, a compressor 12 as a compressor, a condenser 13 as a condenser, and a receiver 14,
This constitutes a known cooling cycle.

The compressor 12 is connected via a magnetic clutch 15,
It operates using an automobile engine 16 connected by a belt as a power source, and a control valve 17. It also incorporates a coil 18 which is a discharge capacity variable means. The coil 18 can set the minimum value of the suction refrigerant pressure of the compressor 12 by applying current, and the control valve 17 performs pressure control so that the suction refrigerant pressure does not fall below the set value.

The condenser 13 is an electric version of the condensing capacity variable device of a condenser known from Japanese Patent Laid-Open No. 2-24220. A bypass pipe line 19 is provided midway from the inlet of the capacitor 13, and an electromagnetic valve 20, which is a condensing capacity variable means, is provided in the middle of the pipe line 19, which opens when a voltage is applied. When the electromagnetic valve 20 opens, the capacitor 13
The refrigerant hardly flows between the inlet of the condenser 12 and the connection part of the conduit 19, the substantial area of the condenser 12 is reduced, and the condensing capacity is reduced.

The heater unit 3 includes a heater 21 that is a heater that uses the cooling water of the engine 16 (temperature: approximately 80°C), an air mix door 22 that controls the proportion of air passing through the heater 21, and a Two mode doors 23a for switching air outlets.

Built-in 23b. Depending on the position of the mode doors 23a and 23b, the air outlet into the vehicle interior is the air outlet 24 and the differential outlet 25 shown in the figure.
There is a "def" blowing out only from the vent, a "vent" blowing out only from the vent 26, and a switch to "B/L" blowing from the vent 26 and the footwell opening 24.

This air conditioner operates in response to instructions from the electronic control circuit 27. The electronic control circuit 27 includes a microcomputer 28 that performs calculations and judgments for controlling. The microcomputer 28 of this embodiment includes a central control unit, a read-only memory (hereinafter referred to as ROM) that stores processing procedures (programs, constants), a random access memory that stores data, and an on/off input/output terminal (hereinafter referred to as ROM).
Ilo), analog-to-digital conversion input terminal (hereinafter referred to as A/D), arbitrary width pulse output terminal (hereinafter referred to as P
It has built-in components such as WM.

The microcomputer 28 is connected to a crystal oscillator 29 having a frequency of I MHz, which constitutes an oscillator that determines the basic cycle. Further, the power source is a battery (not shown).

Next, the input/output of electrical signals to and from the microcomputer 28 will be explained for each device.

Output signals from the air temperature sensor 11 downstream of the evaporator, the air temperature sensor 30 for the vehicle compartment 4, and the outside air temperature sensor 31 are taken into the A/D of the microcomputer 28 via the multiplexer circuit 32.

The intake door 7, the air mix door 22, and the mode doors 23a, 23b each have a motor 33a.
, 33, b, and 33c, and the drive signal is outputted via the motor drive IC 34.

The blower 8 is driven by a motor 35, and the voltage applied to the motor 35 is controlled by a power transistor 37 via a constant voltage circuit 36.

The electromagnetic valve 20 is turned on and off by a relay 39 driven via a transistor 38, and when turned on, refrigerant flows in from the bypass pipe, reducing the condensing capacity.

The magnetic clutch 15 is turned on and off by a relay 40 driven via a transistor 38. There is a high/low pressure switch provided in the receiver 14 between the relay 40 and the magnetic clutch 15, and the refrigerant pressure is 1.1 kgf/c.
When it becomes less than dG or more than 27 kg f /ff1G, the magnetic clutch 14 is turned off.

A current is applied to the coil 18 via a constant current circuit 41 in accordance with a set value of the evaporation pressure of the refrigerant.

The operation panel 42 displays the status and settings of the air conditioner, and the switch words on the operation panel 42 are as follows:
Enter Ilo of the microcomputer 28, and the display section is as follows.
It is controlled via the display drive circuit 43.

Next, the functions of the switches and display section on the operation panel 42 will be explained.

The "AUTO" switch 44 instructs automatic control operation of the air conditioner. The "differential" switch 45 instructs to fix the air blowing into the passenger compartment to the "differential". ” R
The "EC" switch 46 instructs to fix the air intake to "inside air." The "E CON" switch 47 turns off the magnetic clutch 15 and instructs to stop the cooling cycle. The "FF" switch 48 instructs to stop the air conditioner.The "Δ" switch 49 instructs to increase the set value of the cabin air temperature, and the "" switch 50 instructs to decrease the set value of the cabin air temperature. Instruct each.

The "S ET" display 51 shows the set value of the air temperature inside the vehicle, and the "A M B" display 52 shows the air temperature outside the vehicle.
Display each.

The program stored in the ROM of the microcomputer 28 will be explained with reference to the flows shown in FIGS. 2 to 4. Note that the numbers in Figure 1 indicate step numbers.

The microcomputer 28 executes step 100 in FIG. 2 by turning on the ignition switch of the automobile.
Execute processing from. In step 100, "normal control" is executed to control the air conditioner in a normal state.

The control of the electromagnetic valve 20 in "normal control" is off when the outside temperature≧Tal. However, Tal is the first predetermined value and is the predetermined value of the second invention. Further, when the outside air temperature is <Tal, the relationship between the command current of the coil 18 and the downstream air temperature of the evaporator and the target value is determined. In other words, when the current flowing through the coil 18 is the minimum capacity instruction and the evaporator downstream air temperature is higher than the target value, the electromagnetic valve 20 is activated to increase the condensing pressure so that the evaporator downstream air temperature becomes high. Turn on to reduce condensing capacity. On the other hand, when the current applied to the coil 18 indicates the maximum capacity and the evaporator downstream air temperature is higher than the target value, the electromagnetic valve 20 is activated to lower the condensing pressure so that the evaporator downstream air temperature decreases. Turn off to increase condensation capacity.

In step 101, the "AUTO" switch 44
Determine if is pressed. If NO, the process returns to step 100. If YES, in step 102,
1OFF" switch 48 is pressed for 5 seconds or more. If NO, the process returns to step 100.

If YES, the process proceeds to step 103 and enters failure diagnosis control. In other words, failure diagnosis control is based on E
Similar to the method described on pages -45 to E-48, "A
"UTO" switch 44 and "OFF" switch 48
Select by pressing simultaneously for 5 seconds or more.

In step 103, the diagnosis item is set to "'input",
In step 104, 1'fault diagnosis control'', which will be described later, is executed.In step 1.05, it is determined whether only the FF switch 48 has been pressed and a return to normal control has been instructed. If YES, return to step 100 and NO
If so, the process returns to step 103.

Referring to FIG. 3, the "failure diagnosis control" in step 104 will be explained. In step 110, the "AUT○" switch 44
It is determined whether the item is being pressed and an item switching is being instructed. If YES, the diagnostic items are switched in step 111. In step 112, the air temperature sensor 11
, 30. Input the output signals of 31.

In step 113, it is determined whether the diagnosis item is "Pinput". If YES, in step 114, a failure diagnosis of the input system is performed.

In step 115, it is determined whether the diagnostic item is "output". If YES, a failure diagnosis of the output system, which will be described later, is performed in step 116.

In step 117, it is determined whether the item is "adjustment". If YES, the target value is adjusted in step 118.

In step 119, it is determined that the item is "fault display", and the details of the fault are displayed, and the fault diagnosis control is ended.

Referring to FIG. 4, the "output diagnosis" in step 116 will be explained. In step 120, it is determined whether the "Δ" switch 49 is pressed. If YES, in step 121 the coat of the output pattern is changed, which will be described later.

In step 122, it is determined whether the 'TT switch 50 is pressed. If YES, the output pattern code, which will be described later, is switched in step 123.

In step 124, depending on the output pattern code,
With the combination shown in FIG. 5, a signal is output to the output system and the "high force diagnosis" is completed. In addition, the above-mentioned cover turn code is displayed as a number on the "AMB" display 52 on the operation panel 42, and "30" indicating "output diagnosis" is displayed on the "SET" display 51.

Next, FIG. 5 will be explained. The electromagnetic valve 18, which is a condensing capacity variable device, is turned on when the outside air temperature detected by the air temperature sensor 28 is less than Ta2;
Change the last digit of the code to 11111 and notify the operator. Here, Ta2 is a second predetermined value lower than Tal, and is a predetermined value of the third invention.

Coil 18 failure diagnosis is code 1460 I! ("6
1”), code “70” ('“71”), code “80”
” (81″) [Values in parentheses are when outside temperature < Ta2.

] to switch the current flowing through the coil 18. As in the third invention, when the electromagnetic valve 20 is turned on at a low heat load, the condensing capacity is reduced and the refrigerant pressure discharged from the compressor 12 is increased, so that the control range of the evaporation pressure is widened.

Therefore, the temperature of the air blown into the vehicle interior changes greatly, and the operation of the coil 18 can be detected by changes in the thermal sensation, making it easy for a fault inspection operator to diagnose the failure of the coil 17.

A failure diagnosis of the electromagnetic valve 2o is performed by installing a pressure gauge 53 on the discharge side of the compressor 12 and having a failure inspection operator visually check the indicated value. That is, the discharge pressure of the compressor 12 changes as shown in FIG. 6 by turning the electromagnetic valve 20 on and off. Code "80"("81"),
-1-t "91"("90") [The values in parentheses are when outside temperature < Ta2. ], the solenoid valve 2o is turned on and off, and when the indicated value of the pressure gauge 53 changes, it is determined that the solenoid valve 20 is normal. At this time, as in the first invention, the current flowing through the coil 18, which is the discharge capacity variable device, is set to 1.2 A, that is, the discharge capacity of the compressor 12 is directed to the small capacity side. Therefore, the condensation pressure is unlikely to increase, and failure diagnosis of the electromagnetic valve 20 can be performed without activating the high pressure protection switch provided on the receiver 14.

Furthermore, the code "91"("90") (() is
When outside temperature < Ta2. In this case, as in the second invention, the solenoid valve 18 is prohibited from being turned on when the outside temperature≧Ta2, so it is possible to prevent the condensing pressure from becoming too high and damaging the cooling cycle components.

In this embodiment, an outside air temperature sensor is used as the heat load detection means, but a compressor discharge refrigerant pressure sensor may also be used. In addition, in a system equipped with the discharge refrigerant pressure sensor,
Instead of the pressure gauge 53, a detected value from a discharge refrigerant pressure sensor may be used.

According to this embodiment, it is possible to prevent damage to cooling cycle components due to erroneous operation by a failure inspection worker, and furthermore, it is possible to carry out failure inspection over a wide range of outside temperatures.

〔Effect of the invention〕

As described above, according to the present invention, in the first aspect, since the compressor is operated at a small capacity side, the failure of the electromagnetic valve that is the condensing capacity variable device is prevented even in environments where the condensing pressure is low and the outside air temperature is high. It has the effect of making a diagnosis.

In the second aspect of the invention, failure diagnosis of the electromagnetic valve is prohibited when the heat load is high, so that damage to cooling cycle components due to high-pressure refrigerant can be prevented.

In the third invention, when the heat load is low, the current flowing through the coil that is the variable discharge capacity device is set to the small capacity side, so the discharge refrigerant pressure of the compressor becomes high, and the variable condensing capacity device It is effective in diagnosing the failure of electromagnetic valves.

The fourth aspect of the invention has the advantage that the outside air temperature sensor used for air conditioning can be used as a means for determining heat load.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an automobile air conditioner according to an embodiment of the present invention, FIGS. 2 to 4 are flow diagrams of a program stored in the microcomputer of FIG. 1, and FIG. FIG. 6 is a diagram showing the output pattern of the "8 force diagnosis", and FIG. 6 is a diagram showing changes in the discharge pressure of the compressor when the electromagnetic valve is turned on or off. 12...Compressor (compressor), 13...Condenser (condenser), 18...Coil (discharge capacity variable device), 20...Solenoid valve (condensing capacity variable device),
28 Microcomputer (diagnostic control device), 31
... Air temperature sensor (thermal load detection means, outside air temperature detection means), 44. ``AUTO'' switch (indication means), 48... ``OFF'' switch (indication means)
. Agent Tatsu Unuma No. 2 Figure 3 Figure 6 Figure Tano 7 Noj (0C)

Claims (4)

[Claims] 1. A cooling cycle having a condenser equipped with a variable condensing capacity device and a compressor equipped with a variable discharge capacity device, an instruction means for a diagnostic function that outputs a control signal to the variable discharge capacity device in a predetermined pattern, and the instruction means and a diagnostic control means for controlling the variable discharge capacity device when a diagnostic function is selected, wherein the diagnostic control means adjusts the condensing capacity according to the output of the indicating means. An air conditioner for an automobile characterized by controlling a variable device and outputting an instruction to the variable discharge capacity device for a smaller capacity when instructing the variable condensing capacity device to reduce the condensing capacity. Device. 2. An air conditioner for an automobile equipped with a cooling cycle having a condenser equipped with a variable condensing capacity device for the heat load of an automobile, comprising a heat load detection means for detecting the thermal load of the automobile, and the variable condensing capacity device. a diagnosis function instruction means for outputting a control signal to a control signal in a predetermined pattern, and a diagnosis control means for controlling the condensing capacity variable device when the diagnosis function is selected by the instruction means, the diagnosis control means An air conditioner for an automobile, comprising means for prohibiting output of a capacity reduction control signal to the variable condensing capacity device when the thermal load detection unit detects a heat load of a predetermined value or more. 3. A cooling cycle with a condenser equipped with a variable condensing capacity device and a compressor equipped with a variable discharge capacity device, and a diagnostic function that outputs a control signal to the variable discharge capacity device in a predetermined pattern for the heat load of an automobile. and a diagnostic control means for controlling the variable discharge capacity device when a diagnostic function is selected by the indicating means, the heat load detecting the heat load of the automobile. A detection means is provided,
The diagnostic control means controls the condensing capacity variable device according to the output of the instruction means, and when the heat load detecting means detects a heat load below a predetermined value, the diagnostic control means controls the condensing capacity variable device. An air conditioner for an automobile, comprising means for outputting a capacity reduction control signal. 4. The air conditioner for an automobile according to claim 2 or 3, wherein the heat load detection means detects the temperature of outside air.