JP2008241071A - Failure diagnosis device for compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a failure diagnosis device for a compressor capable of properly driving and controlling a linear solenoid even when a current detecting circuit for detecting feedback electric current fails. <P>SOLUTION: This failure diagnosis device for the compressor comprises the linear solenoid 12 for opening and closing a valve 11 (actuator) to allow a refrigerant to flow in and out to the compressor 10, and a controller 24. The controller 24 resets a solenoid resistance value according to feedback electric current when it is determined that an AD value input converting portion 24a and an electric current converting portion 24b (electric current detecting means) are normal, and drives and controls the linear solenoid 12 according to the resistance value. On the other hand, the controller 24 sets a solenoid fixed resistance value when it is determined that the AD value input converting portion 24a and the electric current converting portion 24b are failed, and drives and controls the linear solenoid 12 according to the fixed resistance value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a failure diagnosis device for a compressor, and more particularly to a failure diagnosis device for a compressor having a control device capable of driving and controlling a linear solenoid used in the compressor.

As a control device that drives and controls a linear solenoid, for example, as described in Patent Document 1, a device that drives and controls a linear solenoid used for hydraulic control of an automatic transmission mounted on a vehicle is known. In this control device, a command current value is set in order to generate a predetermined clutch pressure. Further, the current actually flowing through the linear solenoid is monitored and feedback controlled. In this control device, the resistance value stored in the storage device is sequentially corrected so that a current that matches the resistance value of the linear solenoid that changes as the oil temperature changes flows to the linear solenoid. The output voltage value is calculated based on the resistance value and the feedback current value, and is output to the linear solenoid. According to this control device, it is possible to make the current flowing through the linear solenoid substantially coincide with the command current value.
Japanese Patent Laid-Open No. 9-280411

  However, the control device described in Patent Document 1 is not configured to diagnose a failure in a current detection circuit that feeds back while monitoring the current flowing through the linear solenoid. For this reason, if the current detection circuit fails even though the linear solenoid can be driven, it is impossible to output an appropriate output voltage value to the linear solenoid, so the driving of the linear solenoid must be stopped. There was a problem. This problem is not limited to the one that drives and controls the linear solenoid used for hydraulic control of the automatic transmission, and the same problem occurs in the one that drives and controls the linear solenoid used in the compressor.

  An object of the present invention is to provide a compressor failure diagnosis device capable of appropriately driving and controlling a linear solenoid even when a current detection circuit for detecting a feedback current fails.

Means for Solving the Problems and Effects of the Invention

  In order to solve the above problems, a compressor failure diagnosis apparatus according to the present invention detects a current value flowing through a linear solenoid that opens and closes an actuator for opening and closing an actuator for flowing refrigerant into and out of the compressor. And a current detection means for feedback, a failure determination means for determining a failure of the current detection means, and the current detection means detected by the failure determination means when the current detection means is determined to be normal. Solenoid resistance value resetting means for resetting the resistance value of the linear solenoid in accordance with the current value; and when the failure determination means determines that the current detection means has failed, the resistance value of the linear solenoid is A solenoid fixed resistance value setting means for setting the fixed resistance value of a predetermined size capable of opening and closing the actuator; Characterized by comprising a driving control means for driving and controlling the linear solenoid in response to the re-set solenoid resistance value or the set solenoid fixed resistance value.

  In this compressor failure diagnosis apparatus, failure of the current detection means is determined by the failure determination means. When the failure determination means determines that the current detection means is normal, the solenoid resistance value is reset by the solenoid resistance value resetting means. The linear solenoid is driven and controlled by the drive control means in accordance with the reset solenoid resistance value. For this reason, when the current detection means is normal, the driving state of the linear solenoid can be ensured. On the other hand, when it is determined by the failure determination means that the current detection means has failed, the solenoid fixed resistance value is set by the solenoid fixed resistance value setting means, and the drive control means is set according to the set solenoid fixed resistance value. Thus, the linear solenoid is driven and controlled. For this reason, even when the current detection means is out of order, the driving of the linear solenoid is not stopped and the driving state of the linear solenoid can be maintained.

  In implementing the present invention, the failure determination means may be set to determine a failure of the current detection means when the current value detected by the current detection means is not within a predetermined range. is there.

  The failure of the current detection means may be, for example, disconnection or short circuit of the current detection means, or wiring failure, and the current value detected at the time of failure is a value that does not fall within a predetermined range. According to this, it is possible to easily determine the failure of the current detection means by using the feedback current value.

  In the implementation of the present invention, the compressor failure diagnosis device further includes an abnormality determination unit that determines an abnormality of the compressor, and the drive control unit causes the current detection unit to fail due to the failure determination unit. And when the abnormality determining means determines that the compressor is normal, the linear solenoid is driven and controlled according to the set solenoid fixed resistance value, and the failure determining means It may be set so that the drive control of the linear solenoid is prohibited when it is determined that the current detection unit is out of order and the abnormality determination unit determines that the compressor is abnormal. is there.

  According to this, when it is determined by the failure determination means that the current detection means has failed and the abnormality determination means determines that the compressor is abnormal, the drive control means prohibits the drive control of the linear solenoid. For this reason, when the compressor is abnormal, the drive control of the linear solenoid is prohibited, so that the compressor can be prevented from malfunctioning.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a functional block diagram schematically showing an embodiment of a vehicle air conditioning system to which a compressor failure diagnosis apparatus according to the present invention is applied. The vehicle air conditioning system includes a compressor 10, an air conditioning ECU 20, and the like. It has.

  The compressor 10 (compressor) is connected to an evaporator (not shown) and pressurizes the vaporized refrigerant so that the refrigerant is easily liquefied before it is compressed and returned to the liquid. The compressor 10 is of a variable displacement type, for example, and can reduce the discharge capacity of the compressor 10 at the time of low voltage control than that at the time of normal control. The compressor 10 is not limited to a variable displacement type, and may be, for example, a fixed displacement type. The compressor 10 includes a valve 11 and a linear solenoid 12.

  The valve 11 (actuator) has a function of flowing the refrigerant into and out of the compressor 10. The linear solenoid 12 is a well-known one that can linearly open and close the valve 11 in accordance with a control current, and includes a coil, a plunger, and the like that are not shown.

  The air conditioning ECU 20 includes a solenoid drive circuit 21, a solenoid current monitor circuit 22, a compressor pressure monitor circuit 23, and a controller 24. The solenoid drive circuit 21 is composed of an IC, and is connected to the linear solenoid 12 and the controller 24. The solenoid drive circuit 21 supplies a current of a magnitude necessary for driving the linear solenoid 12 in accordance with a control command from the controller 24. To supply.

  The solenoid current monitor circuit 22 is composed of an IC, is connected to the linear solenoid 12 and the controller 24, and outputs a voltage having a magnitude corresponding to the actual current value flowing through the linear solenoid 12 to the controller 24. . The compressor pressure monitor circuit 23 is composed of an IC, and is connected to the compressor 10 and the controller 24. The compressor pressure monitor circuit 23 detects the pressure of the refrigerant in the compressor 10 and outputs it to the controller 24.

  The controller 24 includes a microcomputer including a CPU, a ROM, a RAM, and the like as main components, and repeatedly executes the failure diagnosis program in FIG. 2 stored in the ROM when the air conditioning operation panel 31 is turned on. The controller 24 includes an AD value input conversion unit 24a connected to the solenoid current monitor circuit 22, a current conversion unit 24b connected to the AD value input conversion unit 24a, and a solenoid resistance value calculation connected to the current conversion unit 24b. Unit 24c, output current value calculation unit 24d connected to solenoid resistance value calculation unit 24c, PWM output unit 24e, air conditioning calculation unit 24f and AD value input conversion unit 24g connected to output current value calculation unit 24d, respectively. Functionally equipped.

  The AD value input converter 24a converts the analog input from the solenoid current monitor circuit 22 into a digital output. The current converter 24b converts the voltage value converted into a digital output by the AD value input converter 24a into a current value. That is, the current flowing through the linear solenoid 12 is monitored by the solenoid current monitor circuit 22 and fed back, and the feedback current value is output from the solenoid current monitor circuit 22 to the current converter 24b via the AD value input converter 24a. It has become so. A circuit that connects the solenoid current monitor circuit 22, the AD value input conversion unit 24a, and the current conversion unit 24 to each other (hereinafter referred to as a feedback current detection circuit) serves as a current detection unit.

  The solenoid resistance value calculation unit 24c calculates a solenoid resistance value based on the feedback current value converted by the current conversion unit 24b and the voltage value calculated by the air conditioning calculation unit 24f.

  The output current value calculation unit 24d calculates the output current value based on the solenoid resistance value calculated and reset by the solenoid resistance value calculation unit 24c and the voltage value calculated by the air conditioning calculation unit 24f. The PWM output unit 24e outputs a PWM signal to the solenoid drive circuit 21 so that the linear solenoid 12 is driven (pulse width modulation) at a predetermined frequency based on the output current value calculated by the output current value calculation unit 24d. To do. The output current value calculation unit 24d, the PWM output unit 24e, and the solenoid drive circuit 21 serve as drive control means.

  The air conditioning calculation unit 24 f is connected to the air conditioning operation panel 31 and calculates a voltage value corresponding to the operation content of the air conditioning operation panel 31. The AD value input conversion unit 24g converts the analog input from the compressor pressure monitor circuit 23 into a digital output. The pressure converted into the digital output is input to the output current value calculation unit 24d.

  Next, the operation of the present embodiment configured as described above will be described. The controller 24 repeatedly executes the failure diagnosis program of FIG. 2 every predetermined short time by turning on the air conditioning operation panel 31.

  Execution of this failure diagnosis program is started in step S10. First, the case where the feedback current detection circuit is normal will be described. In this case, the actual current value flowing through the linear solenoid 12 driven by the process of step S11 and the feedback current value detected by the feedback current detection circuit by the process of step S12 are substantially the same. In step S13, “Yes”, that is, it is determined that the feedback current value is normal, and the processing after step S14 is executed.

  In step S14, the solenoid resistance value is calculated based on the feedback current value and the voltage value calculated by the air conditioning calculation unit 24f, and reset as a new solenoid resistance value. In step S15, an output current value is calculated based on the reset solenoid resistance value and the voltage value calculated by the air conditioning calculation unit 24f, and a PWM signal corresponding to the calculated output current value is output to the solenoid drive circuit 21. Output to. After the process of step S15, the execution of the fault diagnosis program is terminated.

  Next, a case where the feedback current detection circuit has failed will be described. This failure is caused by a disconnection or short circuit of the feedback current value detection circuit, or a wiring defect. The feedback current value at this time is extremely large compared to the actual current value flowing through the linear solenoid 12. Or an extremely small value. For this reason, the range of the current flowing through the linear solenoid 12 when the compressor 10 is in a normal operation state is used as a reference range, and the feedback current detection circuit is operated when the feedback current value greatly exceeds or greatly falls below the reference range. It can be presumed that there is a failure. Therefore, when the feedback current detection circuit is out of order, the feedback current value does not fall within the reference range. Therefore, “No” is determined in Step S13, and the processes after Step S16 are executed.

  In step S16, the solenoid fixed resistance value is set as a new solenoid resistance value. This solenoid fixed resistance value is stored in a RAM or the like, and is set to the resistance value of the linear solenoid 12 when the compressor 10 is in a normal operation state. Next, in step S <b> 17, it is determined whether or not an abnormality has occurred in the compressor 10 based on the refrigerant pressure in the compressor 10 detected by the compressor pressure monitor circuit 23. When an abnormality occurs in the compressor 10, the refrigerant pressure in the compressor 10 becomes larger or smaller than the refrigerant pressure in the normal operation state. Therefore, the refrigerant pressure range when the compressor 10 is in a normal operating state is used as a reference range, and when the refrigerant pressure exceeds or falls below this reference range, an abnormality has occurred in the compressor 10. Can be estimated. Therefore, when the compressor 10 is normal, the refrigerant pressure falls within the reference range. Therefore, “Yes” is determined in step S17, and in step S15, the solenoid fixed resistance value and the air conditioning calculation unit 24f are used. An output current value is calculated based on the calculated voltage value, and a PWM signal corresponding to the calculated output current value is output to the solenoid drive circuit 21. After step S15, the execution of the fault diagnosis program is terminated in step S19.

  On the other hand, when an abnormality has occurred in the compressor 10, the refrigerant pressure does not fall within the reference range. Therefore, “No” is determined in step S17, and the PWM signal is sent to the solenoid drive circuit 21 in step S18. In step S19, the execution of the fault diagnosis program is terminated.

  As is apparent from the above description, in the present embodiment, the failure of the feedback current detection circuit is determined by the process of step S13. When it is determined that the feedback current detection circuit is normal, the resistance value calculated by the solenoid resistance value calculation unit 24c is reset as the solenoid resistance value by the process of step S14. In step S15, the linear solenoid 12 is driven and controlled according to the reset solenoid resistance value. For this reason, when the feedback current detection circuit is normal, the driving state of the linear solenoid 12 can be ensured. On the other hand, if it is determined in step S13 that the feedback current detection circuit has failed, the solenoid fixed resistance value is set in step S16. If the compressor 10 is normal, the solenoid in step S15 is processed. The linear solenoid 12 is driven and controlled according to the fixed resistance value. For this reason, even when the feedback current detection circuit is out of order, the driving of the linear solenoid 12 is not stopped and the driving state of the linear solenoid 12 is maintained.

  In the present embodiment, a failure of the feedback current detection circuit is determined using the feedback current value in the process of step S13. Thereby, the failure of the feedback current detection circuit can be easily determined.

  In the present embodiment, it is determined that the feedback current detection circuit has failed by the process of step S13, and the compressor 10 is normal by the process of step S17 based on the refrigerant pressure detected by the compressor pressure monitor circuit 23. Is determined, the linear solenoid 12 is driven and controlled in accordance with the solenoid fixed resistance value in the process of step S15. On the other hand, when it is determined in step S13 that the feedback current detection circuit has failed and in step S17 it is determined that the compressor 10 is abnormal, the drive control of the linear solenoid 12 is performed in step S18. Is prohibited.

  Thereby, when the compressor 10 is abnormal, the drive control of the linear solenoid 12 is prohibited, so that a failure of the compressor 10 can be prevented in advance.

  In the above-described embodiment, the compressor failure diagnosis apparatus according to the present invention is applied to a vehicle air conditioning system. However, the present invention is not limited to this and can be widely applied to compressors using linear solenoids.

The functional block diagram which represented roughly one Embodiment of the air conditioning system for vehicles to which the failure diagnosis apparatus of the compressor of this invention was applied. The flowchart which shows the failure diagnosis control program performed by the controller of FIG.

Explanation of symbols

10 Compressor
11 Valve (actuator)
12 Linear solenoid 20 Air conditioning ECU
21 Solenoid drive circuit (drive control means)
22 Solenoid current monitor circuit (current detection means)
23 Compressor pressure monitor circuit (abnormality judgment means)
24 controller (failure determination means, solenoid resistance value resetting means, solenoid fixed resistance value setting means, drive control means, abnormality determination means)
24a AD value input converter (current detection means)
24b Current converter (current detection means)
24c Solenoid resistance value calculation unit (solenoid resistance value resetting means)
24d Output current value calculation unit (drive control means)
24e PWM output unit (drive control means)
24f Air conditioning calculation unit 24g AD value input conversion unit (abnormality determination means)
31 Air conditioning operation panel

Claims (3)

A linear solenoid that opens and closes an actuator for flowing refrigerant into and out of the compressor;
Current detection means for detecting and feeding back a current value flowing through the linear solenoid;
Failure determination means for determining failure of the current detection means;
Solenoid resistance value resetting means for resetting the resistance value of the linear solenoid according to the current value detected by the current detection means when the failure detection means determines that the current detection means is normal;
Solenoid fixed resistance value that sets the resistance value of the linear solenoid to a fixed resistance value of a predetermined magnitude that can open and close the actuator when the failure determination means determines that the current detection means has failed. Setting means;
A compressor failure diagnosis device comprising: drive control means for driving and controlling the linear solenoid according to the reset solenoid resistance value or the set solenoid fixed resistance value.   2. The compressor failure according to claim 1, wherein the failure determination unit is configured to determine a failure of the current detection unit when a current value detected by the current detection unit is not within a predetermined range. Diagnostic device. The compressor failure diagnosis device further includes an abnormality determination means for determining an abnormality of the compressor,
The drive control means is configured such that when the failure determination means determines that the current detection means has failed and the abnormality determination means determines that the compressor is normal, the set solenoid fixed resistance When the linear solenoid is driven and controlled according to the value, the failure determination means determines that the current detection means has failed, and the abnormality determination means determines that the compressor is abnormal. 3. The compressor failure diagnosis device according to claim 1, wherein the failure diagnosis device is set so as to prohibit the drive control of the linear solenoid.

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