JPH1120464A - Controller for car air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller that can perform positive and appropriate signal processing after detecting abnormality. SOLUTION: A signal from a rotation sensor 25 fitted to a compressor is inputted to a controller 1 for a car air conditioner. This signal is judged by a judging circuit 22 in the controller 1. At the normal time, a state holding means 30 is not driven, and a power source and an electromagnetic clutch 29 are connected to each other. In the case of the occurrence of abnormality to rotation such as lock of a compressor, the state holding means 30 is driven by a signal from the judging circuit 22 so as to cut off power supply to the electromagnetic clutch 29. Since the state holding means 30 is a self-holding type relay or the like, once driven, a current is not applied again to the electromagnetic clutch 29 unless specified release work is performed. The electromagnetic clutch 29 is not therefore connected after the occurrence of failure of the compressor so as to prevent the rupture or the like of a belt for transmitting engine rotation through a pulley.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a car air conditioner, which is suitable for controlling a compressor for a car air conditioner, and particularly for controlling an electromagnetic clutch for transmitting engine rotation to the compressor.

[0002]

2. Description of the Related Art In general, a car air conditioner uses a rotation of an engine to rotate a compressor to compress a refrigerant, and is turned on and off by an electromagnetic clutch provided on a rotary shaft on the compressor side. It is. In other words, the pulley provided on the rotating shaft of the engine and the pulley provided on the rotating shaft on the compressor side are connected by a belt, and the electromagnetic clutch provided between the pulley provided on the compressor side and the compressor body is controlled by a control signal. Turning on and off controls the operation of the car air conditioner itself. Further, this belt is also applied to pulleys of auxiliary equipment such as an alternator and a hydraulic booster, and thus the auxiliary equipment is driven by the same belt.

In such a car air conditioner, for example, if the compressor becomes unable to rotate for some reason, the belt continues to be connected to the engine via the belt unless the electromagnetic clutch is manually switched off. As a result, there is a possibility that the accessories that are linked to the engine may become inoperable due to slipping due to friction or heat generation, and may become in a dangerous state for driving or running. Accordingly, in recent years, a control method has been proposed in which the rotation of the compressor is detected, and the rotation of the compressor is detected, and the slippage of the belt is detected to automatically cut off the power supply to the electromagnetic clutch to avoid danger.

[0004] As an example, the present applicant has filed Japanese Patent Application No.
No. 82947 proposes a control device for a car air conditioner. This control device detects the input signal from the sensor, a start timer that outputs a signal for a fixed time when the power is turned on, and outputs a signal that gradually decreases in response to the signal from the detection circuit or the start timer. A main timer, a determination circuit that outputs a signal when the intensity of a signal output from the main timer exceeds a threshold, and an amplification circuit that supplies power to a control target device by a signal from the determination circuit, and includes a compressor. In the case of abnormal rotation, the power supply to the electromagnetic clutch and the like is surely stopped, and by installing the compressor in or near the compressor of the car air conditioner, the wiring of a long signal line as in the related art is unnecessary.

This control device determines the rotational speed of the compressor based on a signal repeatedly input from, for example, a rotation sensor or the like attached to the compressor. If an error such as a loose belt or compressor lock occurs, the signal from the sensor will not be input or the signal interval will be longer than a predetermined time. Cut off the current,
The purpose is to remove the burden on the belt and prevent the rupture of the belt before it occurs, thereby eliminating the effect on the accessories.

[0006]

In the conventional control device, there is no record as to whether the cause of the stoppage of the compressor in the previous operation was a normal operation or a shutdown due to abnormality detection. I could not do it. Further, once the main power supply of the control device is turned off after the power supply to the electromagnetic clutch is cut off, the control device can be restarted regardless of the previous stop cause. Therefore, for example, when the driver feels a malfunction of the car air conditioner and turns on the power again without noticing the abnormality of the compressor, the electromagnetic clutch is energized again. When there is an abnormality such as rotation failure of the compressor, the control device cuts off the power supply to the electromagnetic clutch.However, until the abnormality is determined, the electromagnetic clutch is connected for a short time, so that the belt is burdensome. Take it. In particular, when the driver repeatedly turns the power on again, there is a problem that the belt may be torn. Furthermore, if the power is turned on when the engine is running at high speed, such as when driving at high speeds, the running state will become unstable due to a sudden increase or decrease in the load on the engine, which may pose a danger in driving. There is.

[0007]

SUMMARY OF THE INVENTION Therefore, in a control device for a car air conditioner according to the present invention, a detection circuit for detecting an input signal from a sensor, and a signal that gradually attenuates at least in response to a signal from the detection circuit are output. A main timer to
A judgment circuit for judging the intensity of the signal output from the main timer and outputting a signal, and a start timer set to input a predetermined signal to the judgment circuit at least until the sensor output is stabilized when the air conditioner is started. Has a power supply to the state holding means in response to a signal from the determination circuit, receives a signal output from the determination circuit, and once the state is switched due to the occurrence of an abnormality, unless a predetermined recovery operation is performed. The provision of the state holding means for preventing power supply to the control target device is provided to appropriately prevent the power supply to the electromagnetic clutch after the occurrence of the abnormality.

Another feature is that the state holding means is constituted by a self-holding type relay such as a latching relay, so that a power source for holding the state is not required.

Still another feature is that the state holding means accumulates the number of times that the determination circuit has issued a determination signal indicating that an abnormality has occurred, and does not supply power to the controlled device when the number of times reaches a predetermined number. In particular, it is possible to restart in an accidental restraint state due to a malfunction of the determination circuit due to noise or a recoverable cause, and it is possible to reliably deal with a complete restraint state.

Another feature is that the control device is installed in the compressor of the car air conditioner or in the vicinity thereof, so that the signal line from the sensor can be shortened, so that the wiring can be facilitated and the mixing of noise can be reduced.

[0011]

Next, an embodiment of the present invention will be described with reference to the drawings. The control device 1 of the present embodiment shown in FIG. 1 is attached to a compressor 2 in an engine room of an automobile or a vicinity thereof. The compressor 2 is provided with a rotation sensor 3 as a sensor connected to a control device, and a temperature switch 4. The rotation sensor 3 is connected to the control device 1 by a signal line 5. By attaching the control device 1 to the compressor 2 or its vicinity,
Since the signal line 5 can be shortened as compared with the case where the control device is installed in the vehicle cabin, it is possible to reduce the entry of noise from the signal line. The control device 1 has a temperature switch 4
The power supply line 6 is connected to the power supply line 6 via a connector 7 and a switch SW. Therefore, when the compressor is overheated, the power supply to the electromagnetic clutch is reliably shut off by the temperature switch 4. In addition, the power supply line 6 is connected to the electromagnetic clutch 9 as a device to be controlled by the connection wire 8 via the control device 1.
It is connected to the.

One of the electromagnetic clutches 9 is connected to the rotating shaft of the compressor 2 and the other is connected to the pulley 10, so that the electromagnetic clutch 9 is not connected and the pulley 10 can rotate freely while no power is supplied. Therefore, while the engine is rotating, the pulley 10 interlocked with the engine is constantly rotating by a belt (not shown). However, the rotation is transmitted to the compressor until the air conditioner is turned on and the electromagnetic clutch 9 is supplied with power. Not done.

When the air conditioner is turned on, the control device 1
Power is started to the electromagnetic clutch 9 via the
0 and the rotor of the compressor 2 are directly connected. Thus, the rotor starts rotating, and a signal from the rotation sensor 3 that has detected the rotation is sent to the control device 1 via the signal line 5. This signal is interlocked with the movement of the rotor of the compressor. For example, if the minimum rotation speed of the compressor during idling of the engine is 600 rpm or more, it is repeatedly output at intervals of at least 100 ms or less.

At the moment when the air conditioner is switched on, the control device 1 does not output the rotation sensor 3 because the electromagnetic clutch 9 is not connected and the compressor 2 does not rotate. Therefore, in the case of a circuit configuration in which the signal output from the determination circuit is amplified and the power is supplied to the electromagnetic clutch by repeatedly supplying the sensor output, the electromagnetic clutch cannot be permanently connected as it is. Further, if the determination circuit starts signal determination at the same time as the air conditioner starts up, it may be determined that the rotation is abnormal before the intensity and the interval of the sensor output satisfy predetermined conditions.

For this reason, in the embodiment, a predetermined time, such as 0.5 minute, is set at the time of startup by a start timer described later.
A signal for a second is input to the determination circuit of the control device 1 so that the electromagnetic clutch 9 is forcibly connected regardless of the presence or absence of a normal signal. After this time elapses, the control device 1 determines the signal from the rotation sensor 3 to supply power to the electromagnetic clutch 9 and perform a shut-off operation when an abnormality occurs. That is, if the signal interval is a predetermined interval as described above, for example, 100 ms or less, the rotation of the compressor is determined to be normal and the power supply to the electromagnetic clutch is continued, and if there is no other signal or the signal interval exceeds 100 ms, Cuts off the power supply to the electromagnetic clutch.

Further, the control device 1 of the present invention inputs information such as the number of revolutions of the engine, so that when the air conditioner is turned on, the engine is turned off, and then the engine is started again, the control device 1 operates before starting the engine. Start the judgment operation and determine whether the compressor is unrotatable and shut off, or if the one that was rotating normally shuts off the power supply at the same time the car engine was turned off. Appropriate measures can be taken so that when the engine is stopped, the abnormality of the compressor is not determined.

For example, when the compressor is unable to rotate for some reason, the output signal from the rotation sensor becomes longer than the above-mentioned time interval or is not output at all even though the engine is running. If the signal from the rotation sensor is not output within a predetermined time interval in this way, the control device determines that the compressor has failed and the belt has slipped, and cuts off the power supply to the electromagnetic clutch, and turns off the pulley. Detach it from the compressor so that it can rotate freely. In this way, the belt is prevented from being torn due to slippage.

Conventionally, even if the power supply to the electromagnetic clutch is cut off, once the power supply of the control device is turned off, the power supply to the electromagnetic clutch can be performed again. In other words, since the power supply of the control device is linked to the car air conditioner, when the engine is stopped or once the power supply is turned off by operating the car air conditioner, the control device does not retain the information of the previous stop cause. Judge that it is normal and turn on the power again. Therefore, at the time of re-energization, the compressor is forcibly connected for a predetermined time as described above even if the compressor cannot rotate, so that the load on the belt has not been sufficiently reduced.

Therefore, in the present invention, by providing the state holding means in the control circuit, when the power supply to the electromagnetic clutch is interrupted by the abnormality determination, the abnormality determination state is maintained even if the power is once turned off. When the power is supplied again, the power supply to the electromagnetic clutch is not restarted. As the state holding means, it is preferable to use a means for mechanically storing an abnormality determination state by a self-holding relay such as a latching relay, or a means for electrically storing the state by an electronic circuit.

In FIG. 1, a latching relay 11 which is a self-holding type relay is provided in the control device 1 as a state holding means, and a connection wire 8 to an electromagnetic clutch 9 is connected via the latching relay 11. I have. The latching relay 11 has a drive coil and a switching contact. Usually, the connection wire 8 is electrically connected by the switching contact to supply power to the electromagnetic clutch 9. The latching relay 11 returns to the manual state once the switching contact has once operated to maintain the state in a certain direction, or returns unless a special means such as inputting a current to the driving coil for switching the holding state in the reverse direction is taken. It does not. If a rotational abnormality occurs in the compressor 2 for some reason and the control device 1 determines that there is an abnormality based on a signal from the sensor 3, the drive coil of the latching relay 11 is energized to open the switching contact, thereby connecting the connection wire 8. The power supply to the electromagnetic clutch 9 is cut off. For this reason, the pulley 10 is separated from the rotor of the compressor, and can freely rotate, and the load on the belt is eliminated. Further, even if the power supply to the air conditioner body, that is, the power supply to the control device 1 is cut off, the abnormality determination state of the latching relay 11 is maintained as it is, so that even if the air conditioner is switched on again, the electromagnetic clutch remains in the conventional state. There is no connection. Further, since the latching relay 11 does not require a power supply for maintaining the state, it is possible to reliably maintain the abnormality determination state.

The signal processing of the control device 1 will be described with reference to the block diagram shown in FIG. 2 and the waveform diagram of FIG. In the control device of the present invention, when a power switch (not shown) of the car air conditioner is turned on (T1 in FIG. 4), the start timer 21 outputs a predetermined time, for example, 0.5 seconds in conjunction therewith. 27 output is started. The main timer 27 outputs a signal of a predetermined value when receiving a signal from the start timer 21 or an output signal from the sensor 25 rectified and amplified by the detection circuit 26, and gradually reduces the output when the input of the signal is interrupted. The output is input to the determination circuit 22.
While the output from the start timer 21 is present, the main timer 27
Output signal exceeds the threshold value S of the determination circuit 22,
The determination circuit 22 makes the same determination as when a signal from the sensor 25 is input. In the embodiment, the judgment circuit 2
Reference numeral 2 denotes that the signal (the output of the determination circuit in FIG. 4) to the state holding means 30 is not output while the signal from the sensor is being input, and thus the activation timer 21
Is not output from the determination circuit during the operation of.

The state holding means 30 has a switching unit for switching the connection state and a driving unit for operating the switching unit. The switching unit normally connects the electromagnetic clutch 29 to a power supply. The output from the amplifying circuit 23 that has received the output of the determination circuit is input to the driving coil of the driving unit of the state holding means 30, that is, a latching relay. Start timer 2
As described above, during the operation of No. 1, there is no output from the determination circuit 22, and no output from the amplifier circuit 23 to the state holding means 30. Therefore, while the start timer 21 is operating, regardless of the presence or absence of a signal from the sensor 25, the state holding unit 3
0 never switches. Thus, when the air conditioner starts up, the connection state between the electromagnetic clutch 29 and the power supply is maintained, and the sensor 2 that detects the rotation of the compressor is provided.
Until the output of No. 5 satisfies the predetermined condition, the electromagnetic clutch 29 can be reliably driven. Here, the output from the activation timer 21 is transmitted to the determination circuit 2 via the main timer 27.
2, but may be input directly to the determination circuit 22, for example.

An engine drive signal is input to the determination circuit 22, and a signal of a predetermined value is output according to a signal from the main timer 27 only when the engine is running. For example, if the operation state of the engine is not taken into consideration, it is natural that the compressor does not rotate when the engine is turned on and off with the air conditioner switch on, or when the engine is not running when a so-called engine stall occurs. Despite this, it may be determined that a rotation abnormality has occurred. Therefore, in the embodiment, a judgment signal corresponding to the operating state of the engine is output by inputting a drive signal of the engine to the judgment circuit, so that only when the power of the air conditioner is turned on before starting the engine, etc. In this case, the erroneous determination as described above is not performed. In addition, by starting the start timer 21 when the engine is started, it is possible to surely shift to clutch control of the compressor when the engine is started.

The amplification circuit 23 outputs a bias voltage to the detection circuit 26 through the temperature compensation circuit 28 and the sensor 25. Thus, at the same time as the electromagnetic clutch is connected, for example, 0.
By applying a bias voltage of about 5V, it is possible to shift to the threshold value of the detection circuit even when the rotation speed is low and the signal from the sensor is small, such as during idling, and the signal from the sensor is reliably amplified and shaped. Then, the main timer 27 is driven.

When there is no abnormality in the compressor or the like, when the output from the start timer 21 stops (T2 in FIG. 4), the signal output from the sensor 25 satisfies predetermined conditions for both signal strength and signal interval. The output is the judgment circuit 2.
The judgment circuit keeps the value equal to or larger than the threshold value of 2 and receives it, and performs the normal processing. In the embodiment, the output from the determination circuit 22 is not performed, the state holding unit 30 maintains the connected state, and the electromagnetic clutch 29 connected to the power supply via the switching unit of the state holding unit 30 continues to be driven.

A temperature compensating circuit 28 is provided between the sensor and the amplifying circuit. By changing the bias voltage in accordance with a change in the sensitivity of the detecting circuit due to a change in ambient temperature, the detection sensitivity to the sensor signal is substantially reduced. Therefore, an appropriate operating point can be maintained over a wide temperature range.

When an abnormality occurs in the compressor and the interval (t in FIG. 4) of the output signal from the sensor 25 exceeds a predetermined time (T3 in FIG. 4), for example, 100 ms, the output of the main timer, which gradually decreases, is determined by the judgment circuit 22. Is smaller than the threshold value S. Therefore, an output is made from the determination circuit 22 that has determined that an abnormality has occurred. The output of the determination circuit is input as a drive signal to the drive unit of the state holding unit 30 via the amplifier circuit 23, and the output unit of the state holding unit 30 is switched to a different state, that is, a state of interrupting the power supply to the electromagnetic clutch 29. The supply of electric power to the electromagnetic clutch 29 is stopped.

Conventionally, if the power supply is once turned off and then turned on again, a signal is output from a start-up timer, and the determination circuit determines that it is normal, thereby supplying power to the electromagnetic clutch again. On the other hand, in the control device of this embodiment, a latching relay, that is, a self-holding type state holding means 30 is provided between the power supply and the electromagnetic clutch. Therefore, once the drive unit of the state holding unit 30 is driven by the signal amplified from the determination circuit 22 via the amplification circuit 23, the electromagnetic wave is not affected by the start timer or the sensor regardless of the signal from the sensor until a predetermined recovery operation is performed. No power is supplied to the clutch.

In this embodiment, an example is described in which the output of the state holding means 30 directly cuts off the power supply to the electromagnetic clutch 29 when the compressor is abnormal, but the output of the state holding means is, for example, a judgment circuit. Alternatively, the signal sent from the amplifier 22 to the amplifier circuit 23 may be cut off or switched so as to maintain the same signal as that at the time of occurrence of an abnormality, so that the current supply path provided thereabove may be cut off.

As shown in FIG. 3, the signals sent from the start timer 21 and the main timer 27 to the judgment circuit 32 are cut off by the state holding means 40 or the input state to the judgment circuit 32 is maintained in the same manner as when an abnormality occurs. May be switched to. In this embodiment, the same parts as those in FIG. 2 are denoted by the same reference numerals, and the description of each part will be omitted. In this embodiment, the output from the main timer 27 is normally sent to the determination circuit 32 through the state holding means 40. When there is no abnormality in the rotation of the compressor, the output from the determination circuit 32 drives the electromagnetic clutch 29 via the amplification circuit 33 including the signal amplification circuit and the power amplification circuit. Another output from the determination circuit 32 is connected via an amplifier circuit (not shown) so as to be input to the drive unit of the state holding means 40. However, the output from the determination circuit when no abnormality determination is made is performed. In this state, the state holding means 40 is not driven, and the signal from the main timer 27 is sent to the determination circuit as it is via the state holding means.

When it is determined that there is an abnormality in the rotation of the compressor, the signal output for driving the electromagnetic clutch from the determination circuit 32 is shut off, and at the same time, a drive signal is sent to the drive section of the state holding means 40. The signal from the main timer 27 is interrupted or switched to the determination circuit so that the same input state as that at the time of occurrence of an abnormality is maintained. Therefore, even if a signal is output from the start timer 21 when the engine is started after the state holding means 40 is switched, the signal is not transmitted to the determination circuit 32 and the electromagnetic clutch 29 is not driven.

In either of the above-described embodiments, after the determination circuit determines that the rotation of the compressor is abnormal and switches the state holding means, the power is supplied to the electromagnetic clutch unless the state holding means is restored. It will not be done. Here, the output unit of the state holding means has another circuit in addition to the circuit for stopping the power supply to the electromagnetic clutch, so that, for example, a warning lamp or the like indicating that the compressor has stopped due to an abnormality in the compressor can be turned on.

The state holding means does not mechanically store the abnormality determination state like the above-mentioned latching relay.
For example, when an electronic circuit such as a flip-flop circuit or the like that is electrically stored is used, a circuit that is always connected to a battery is required as a power source. And the like, it becomes very easy to set conditions and the like for determining an abnormality as compared with a mechanical storage method.
In other words, until a predetermined number of times, for example, three or five abnormalities are determined, the power is turned on and the device starts up normally.
Beyond that, the circuit can be interrupted. This function may of course be provided in the determination circuit. In this case, a mechanical state holding means such as a latching relay can be used.

In this case, when the compressor suddenly enters the completely locked state, the abnormality determination signal continues to be output, but is counted only once as it is. Therefore, for example, an AND using an abnormality determination signal and a clock pulse
By providing a circuit and counting its output, the state holding means can be driven reliably regardless of whether the abnormality determination signal is of a short-term repetition or of a long-term.

The number of times can be processed in association with the operation time. For example, when the compressor has been operated a predetermined number of times during one operation time, the possibility of the compressor failure is high, and when the predetermined number of operations is reached during a large number of operations for several months, the probability of failure is low. The determination circuit performs an abnormality determination based on this point, so that more appropriate processing can be performed for an accidental abnormality or malfunction.

By doing so, it is possible to restart a malfunction of the judgment circuit due to noise or an accidental restraint state due to a recoverable cause, and to reliably cope with a complete restraint state. It becomes possible.

The output of the judgment circuit and the output of the amplification circuit associated therewith are assumed to use a latching relay in the waveform diagram of FIG. As described above, depending on the circuit configuration of the state holding means and the entire control device, it is needless to say that the level may be high at the normal time and low at the time of abnormality determination.

[0038]

According to the control device for a car air conditioner of the present invention, by providing the state holding means for storing the stop due to the abnormality determination, the recovery processing is performed on the state holding means after the rotation is determined to be abnormal. No power is supplied to the electromagnetic clutch unless performed. Therefore, the belt is prevented from tearing,
It is possible to prevent a situation such as a stop of the engine due to a stop of the auxiliary equipment.

When a means for mechanically storing an abnormality determination state such as a self-holding type latching relay is used as the state holding means, a power source for maintaining the state is not specially required and the circuit is simplified. If an abnormality occurs, the power supply to the electromagnetic clutch can be reliably shut off even after the power is turned off.

In the case where an electronic circuit is used to electrically store data, the circuit is normally started when the power is turned on until the abnormality is determined a predetermined number of times, and the circuit is cut off when the power is exceeded. You can do so. For this reason, a malfunction can be caused in the determination circuit due to noise or the like, and a temporary restraint state due to a recoverable cause can be restarted, and a complete restraint state can be reliably dealt with.

Further, by installing the control device in the compressor of the car air conditioner or in the vicinity thereof, the signal line from the sensor can be shortened, so that the wiring can be facilitated and the mixing of noise from the signal line can be reduced. .

[Brief description of the drawings]

FIG. 1 is an example of a wiring diagram of a control device for a car air conditioner of the present invention.

FIG. 2 is a block diagram showing one embodiment of a control device for a car air conditioner of the present invention.

FIG. 3 is a block diagram showing another embodiment of the control device for a car air conditioner of the present invention.

FIG. 4 is an example of a waveform diagram of the control device for a car air conditioner of the present invention.

[Explanation of symbols]

 1: Control device 2: Compressor 3, 25: Sensor 4: Temperature switch 5: Signal line 6: Power supply line 7: Connector 8: Connection wire 9, 29: Electromagnetic clutch 10: Pulley 11, 30, 40: State holding means 21 : Start timer 22, 32: Judgment circuit 23, 33: Amplifier circuit 27: Main timer

Claims (4)

[Claims] 1. A detection circuit for detecting an input signal from a sensor, a main timer for outputting a signal that attenuates gradually at least in response to a signal from the detection circuit, and determining a strength of a signal output from the main timer. And a start-up timer set to input a predetermined signal to the determination circuit at least until the sensor output becomes stable when the air conditioner is started, and according to a signal from the determination circuit. After the power is supplied to the state holding means, the signal output from the determination circuit is received, and once the state is switched due to the occurrence of an abnormality, the power is not supplied to the controlled device unless a predetermined recovery operation is performed. A control device for a car air conditioner, characterized by comprising a state holding means. 2. The control device for a car air conditioner according to claim 1, wherein the state holding means is constituted by a self-holding relay. 3. The state holding means accumulates the number of times the determination circuit has issued a determination signal indicating that an abnormality has occurred, and does not supply power to the control target device when the number reaches a predetermined number. The control device for a car air conditioner according to claim 1. 4. The control device for a car air conditioner according to claim 1, wherein the control device is installed at or near a compressor of the car air conditioner.