JP2022177635A - Method for controlling vehicular air conditioner and vehicular air conditioner - Google Patents

Abstract

To provide a method for controlling a vehicular air conditioner and a vehicular air conditioner which can determine a failure in a compressor due to the sticking of a clutch, and which can prevent stop of a driving machine by eliminating the sticking of the clutch.SOLUTION: In a vehicular air conditioner 1 comprising a compressor 3 to which power of an engine 2 is transmitted via an electromagnetic clutch 5, an electronic control unit 21 detects a revolution speed of the engine 2 and detects a compression pressure of the compressor 3 corresponding to the revolution speed, and determines whether sticking occurs in the electromagnetic clutch 5 on the basis of a change in the detected revolution speed and a change in the detected compression pressure. When determining that the sticking occurs in the electromagnetic clutch 5, even after an instruction to stop the compressor 3 is provided, the electronic control unit 21 controls the revolution speed of the engine 2 so that torque generated by the engine 2 becomes greater than reference torque set so as to correspond to a state where the electromagnetic clutch 5 of the compressor 3 is disconnected.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle air conditioner control method and a vehicle air conditioner.

2. Description of the Related Art Air conditioners used in vehicles such as automobiles are equipped with a compressor to which power from a driving machine such as an engine or a motor is transmitted via a clutch. In such a vehicle air conditioner, the driving state of the compressor is adjusted by controlling the on/off state of the clutch and the rotational speed of the driving machine. Techniques for diagnosing compressor failures due to stuck clutches are also known.

For example, in a compressor failure diagnosis method disclosed in Patent Document 1, the engine speed is detected, and when a first decrease in the engine speed is detected while the compressor is operating, the operation of the compressor is stopped. , the compressor is reactivated after a first predetermined period of time has elapsed since the compressor was deactivated. Then, when a second decrease in engine speed is detected within a second predetermined period of time from the reactivation of the compressor, it is determined that the compressor has failed.

JP 2014-46728 A

However, with regard to the prior art related to the control of the vehicle air conditioner as described above, although it is possible to judge the failure of the compressor due to the sticking of the clutch, there is a problem that recovery from the failure is not expected. There is If the control of the air conditioning system is continued while the clutch is stuck and the compressor failure is determined, there is a risk that the driving equipment such as the engine and motor will be overloaded and stop (engine stall, etc.). There was room.

SUMMARY OF THE INVENTION The present invention has been made in view of such a situation, and its object is to make it possible to determine whether the compressor has failed due to the stuck clutch, and to stop the driving machine by eliminating the stuck clutch. It is an object of the present invention to provide a vehicle air conditioner control method and a vehicle air conditioner that can prevent this.

In order to achieve the above object, one aspect of the present invention provides a control method for a vehicle air conditioner having a compressor to which power of a driving machine is transmitted via a clutch portion. This control method detects the rotational speed of the driving machine, detects the compression pressure of the compressor corresponding to the rotational speed, and changes the detected rotational speed of the driving machine and the compression pressure of the compressor. Based on the above, it is determined whether or not the clutch portion is stuck, and if it is determined that the clutch portion is stuck, even after an instruction to stop the compressor is given, the drive is stopped. The rotation speed of the driving machine is controlled so that the torque generated by the machine becomes larger than the reference torque set corresponding to the disengaged state of the clutch portion of the compressor.

According to the method for controlling a vehicle air conditioner according to the present invention, it is possible to easily determine whether or not the clutch portion is stuck, and to increase the torque generated by the starter before the drive machine stops due to an overload condition. be able to. As a result, it is possible to eliminate the sticking of the clutch portion, avoid the continuation of the abnormal state of the compressor, and prevent the stoppage of the driving machine.

1 is a conceptual diagram showing a schematic configuration of a vehicle air conditioner according to an embodiment of the present invention; FIG. It is a perspective view which shows an example of the compressor in the said embodiment. FIG. 3 is a sectional view taken along the line AA of FIG. 2 (disconnected state of the electromagnetic clutch); FIG. 3 is a cross-sectional view taken along the line AA of FIG. 2 (connected state of the electromagnetic clutch); It is a flow chart for explaining the control operation in the above-mentioned embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a conceptual diagram showing a schematic configuration of a vehicle air conditioner according to one embodiment of the present invention.
In FIG. 1, a vehicle air conditioner 1 includes a compressor 3 in a power unit mounting room E in which a power unit such as an engine and a motor in a vehicle such as an automobile is mounted. An example of a vehicle equipped with an engine 2 as a power unit will be described below. The compressor 3 is operated by power transmitted from the engine 2 to compress and discharge the refrigerant enclosed therein.

Power is transmitted from the engine 2 to the compressor 3 via a belt 4 and an electromagnetic clutch 5 . The belt 4 is stretched over a pulley 2 a provided on the engine 2 and a pulley 3 a provided on the compressor 3 . The electromagnetic clutch 5 is provided on the compressor 3 side, is electrically connected to the pulley 3 a when the compressor 3 is driven, and transmits power from the engine 2 to the compressor 3 . The state (connection or disconnection) of the electromagnetic clutch 5 is controlled according to a control signal output from an electronic control unit (ECU) 21 . In this embodiment, the engine 2 corresponds to the "driving machine" of the present invention, the electromagnetic clutch 5 corresponds to the "clutch section" of the present invention, and the electronic control unit 21 corresponds to the "determination section" and the "control section" of the present invention. Equivalent to

Refrigerant compressed by the compressor 3 is sent to the condenser 7 through the discharge hose 6 . The condenser 7 cools and liquefies the refrigerant (gas) compressed by the compressor 3 . Outside air is drawn into the condenser 7 by a fan 8, and cooling of the refrigerant is performed using the outside air. Refrigerant (liquid) cooled by condenser 7 is sent to car air conditioner (HVAC) 10 through liquid pipe 9 .

The car air conditioner 10 is arranged on the passenger compartment R side and has an expansion valve 11 and an evaporator 12 . The expansion valve 11 injects the refrigerant liquefied by the condenser 7 through a small nozzle hole, and sends the easily vaporizable mist-like refrigerant into the evaporator 12 . In the evaporator 12, the atomized refrigerant takes heat from the surroundings and evaporates. As a result, the evaporator 12 is cooled, and cool air is generated by blowing air from a blower fan or the like (not shown) around the evaporator 12 . The refrigerant vaporized by the evaporator 12 is returned to the compressor 3 via the expansion valve 11 and the suction hose 13 and compressed again.

FIG. 2 is a perspective view showing an example of the compressor 3. As shown in FIG. 3 and 4 are sectional views taken along the line AA of FIG. 2. FIG. 3 shows the state of the compressor 3 when the electromagnetic clutch 5 is disconnected, and FIG. 4 shows the state of the compressor 3 when the electromagnetic clutch 5 is connected. As shown in FIGS. 2 to 4, one axial end of the compressor 3 is provided with a pulley 3a on which a belt 4 is hung. The pulley 3 a is rotatably supported by bearings 3 b and receives power from the engine 2 transmitted via the belt 4 . A shaft 3d is connected to the pulley 3a via an electromagnetic clutch 5 and a hub 3c.

The electromagnetic clutch 5 has an armature 5a arranged axially outside the pulley 3a of the compressor 3, as shown in FIGS. The armature 5a is fitted to the hub 3c by means of an elastic member 3e such as a leaf spring or rubber, and is configured to be movable toward the pulley 3a. One axial end of the shaft 3d is fastened to the hub 3c with a bolt 3f. Although not shown, a swash plate and a piston are connected to the other end of the shaft 3d, and the rotation of the shaft 3d causes the piston to move in the axial direction, thereby compressing the refrigerant in the cylinder.

An electromagnetic coil 5b is arranged on the opposite side of the armature 5a across the pulley 3a. Electric power from a vehicle power source such as a battery (not shown) is supplied to the electromagnetic coil 5b through a relay 5c and a thermal fuse 5d. The relay 5c has a coil portion and a contact portion. According to the control signal from the electronic control unit 21, the voltage applied to the terminal T1 connected to the coil portion is controlled to open and close the contact portion. The output voltage of the vehicle power supply is applied to the terminal T2 connected to the contact portion, and when the contact portion is closed and the relay 5c is turned on, the voltage is applied to the electromagnetic coil 5b via the thermal fuse 5d. , the electromagnetic coil 5b is energized.

When the electromagnetic coil 5b is energized, the magnetic force generated by the electromagnetic coil 5b draws the armature 5a toward the electromagnetic coil 5b, and the armature 5a contacts and is attracted to the axially outer end face of the pulley 3a. A thick line in FIG. 4 indicates an attraction surface F between the armature 5a and the pulley 3a when the electromagnetic coil 5b is energized. The armature 5a attracted to the pulley 3a is rotated by power transmitted from the pulley 2a of the engine 2 to the belt 4 and the pulley 3a of the compressor 3 in this order. The rotation of the armature 5a also rotates the shaft 3d connected to the armature 5a via the elastic member 3e and the hub 3c, thereby compressing the refrigerant.

When the relay 5c is turned off or the thermal fuse 5d is actuated to de-energize the electromagnetic coil 5b, the attraction of the armature 5a to the pulley 3a is released. When the electromagnetic coil 5b is not energized, an air gap G is formed between the armature 5a and the pulley 3a as shown in FIG. This air gap G is, for example, about 0.5 mm.

However, when the electromagnetic clutch 5 is stuck, the armature 5a is attracted to the pulley 3a according to the control signal from the electronic control unit 21 even if no voltage is applied to the terminal T1 of the relay 5c. keep doing In this case, no air gap G is formed between the armature 5a and the pulley 3a. The fixation of the electromagnetic clutch 5 in the present embodiment means a state in which the metal surfaces of the armature 5a and the pulley 3a are adhered due to surface roughness (fixation of the armature 5a and the pulley 3a), and a state in which the metal surfaces of the armature 5a and the pulley 3a are adhered to each other, and a state in which the metal surfaces of the armature 5a and the pulley 3a are adhered to each other. and a state in which the contact portion is closed even though no voltage is applied to the relay 5c (sticking of the contact portion of the relay 5c). In the vehicle air conditioner 1 according to the present embodiment, the electronic control unit 21 executes control for eliminating such sticking of the electromagnetic clutch 5 .

The electronic control unit 21 performs control to activate (turn on) or stop (turn off) the compressor 3 via the electromagnetic clutch 5, and to perform control to adjust the rotation speed of the engine 2 according to the driving state of the compressor 3. is possible. Specifically, the electronic control unit 21 includes a processor such as a CPU, a non-volatile memory such as a flash ROM, a volatile memory such as a RAM, an input/output interface with external devices, and a bus that connects them so as to be able to communicate with each other. It is equipped with a well-known microcomputer. The electronic control unit 21 is activated when an ignition switch (not shown) of the vehicle is turned on and connected to the power supply of the vehicle. Signals output from a pressure sensor (PS) 22, a rotation speed sensor (RS) 23, and the like are input to the electronic control unit 21, respectively.

A pressure sensor 22 measures the pressure of the refrigerant compressed by the compressor 3 . In this embodiment, the pressure sensor 22 is arranged, for example, on the liquid pipe 9 on the discharge side of the compressor 3 . The pressure sensor 22 measures the pressure of the refrigerant passing through the condenser 7 and flowing through the liquid pipe 9 toward the expansion valve 11 and outputs a signal indicating the measurement result to the electronic control unit 21 . Note that the arrangement of the pressure sensors 22 is not limited to the above example.

The rotation speed sensor 23 measures the crank angle of the pulley 2a on the engine 2 side using, for example, an angle detection device or the like, and measures the rotation speed of the engine 2 from the measured value. The rotation speed sensor 23 outputs a signal indicating the measured rotation speed of the engine 2 to the electronic control unit 21 . In addition, in this embodiment, the pressure sensor 22 and the rotational speed sensor 23 correspond to the "detector" of the present invention.

Next, the control operation of the vehicle air conditioner 1 according to this embodiment will be described in detail with reference to the flowchart shown in FIG.
In the vehicle air conditioner 1 configured as described above, the ignition switch of the vehicle is turned on in step S10 of FIG. The driving function of the vehicle is turned on.

Then, in step S20, when the air conditioner switch (not shown) of the air conditioner operation panel arranged around the instrument panel in the passenger compartment R is turned on, the air conditioner switch instructs the electronic control unit 21 to operate the compressor 3. Given. When the automatic air conditioner function is enabled, an instruction to operate (or stop) the compressor 3 is automatically given to the electronic control unit 21 according to the relationship between the air conditioner set temperature and the vehicle interior temperature. be done.

The electronic control unit 21 that has received the instruction to operate the compressor 3 connects the electromagnetic clutch 5 and controls to operate the compressor 3, and increases the rotation speed of the engine 2 in accordance with the increase in load associated with the operation of the compressor 3. Perform control to raise. As a result, the cooling function of the car air conditioner 10 is started and the air conditioner control is turned on.

In subsequent step S30, the electronic control unit 21 detects the rotation speed of the engine 2 indicated by the output signal from the rotation speed sensor 23, and detects the compression pressure of the compressor 3 indicated by the output signal from the pressure sensor 22. . The detection of the rotational speed of the engine 2 and the compression pressure of the compressor 3 by the electronic control unit 21 is repeatedly executed at a predetermined period p while the air conditioner control is on. As a result, the electronic control unit 21 acquires and stores data relating to temporal changes in the compression pressure of the compressor 3 corresponding to the rotational speed of the engine 2 .

In the next step S40, the electronic control unit 21 determines whether or not an instruction to stop the compressor 3 has been given. The instruction to stop the compressor 3 is given when the above-described operation of switching off the air conditioner switch is performed, or when the vehicle interior temperature falls below the air conditioner set temperature when the automatic air conditioner function is enabled. Given when interrupted. When the instruction to stop the compressor 3 is given to the electronic control unit 21 (YES), the process proceeds to the next step S50.

In step S<b>50 , the electronic control unit 21 performs control to disconnect the electromagnetic clutch 5 and stop the compressor 3 . Specifically, a control signal is output from the electronic control unit 21 to the electromagnetic clutch 5 to turn off the voltage applied to the terminal T1 connected to the coil portion of the relay 5c. In the electromagnetic clutch 5 which receives this control signal, the contact portion of the relay 5c is opened, the electromagnetic coil 5b is de-energized, and the attraction of the armature 5a to the pulley 3a is released. At this time, if the electromagnetic clutch 5 is stuck, that is, if the armature 5a and the pulley 3a are stuck, or the contact portion of the relay 5c is stuck, voltage is applied to the terminal T1 of the coil portion of the relay 5c. Despite this, the armature 5a continues to be attracted to the pulley 3a, resulting in an abnormal state in which the electromagnetic clutch 5 is not disconnected.

Therefore, in the subsequent step S60, the electronic control unit 21 detects changes in the rotation speed of the engine 2 using the output signal from the rotation speed sensor 23, and changes in the compressor 3 detected using the output signal from the pressure sensor 22. Based on changes in the compression pressure, it is determined whether or not the electromagnetic clutch 5 is stuck.

The determination of the presence or absence of sticking in the electromagnetic clutch 5 is made when the compression pressure of the compressor 3 rises as the number of revolutions of the engine 2 increases after an instruction to stop the compressor 3 is given (after YES in step S40). Alternatively, when the compression pressure of the compressor 3 decreases as the rotation speed of the engine 2 decreases, it is determined that the electromagnetic clutch 5 is stuck; otherwise, the electromagnetic clutch 5 is stuck. determine that it is not. In other words, if the electromagnetic clutch 5 is in a normal state after the compressor 3 is instructed to stop, the power from the engine 2 will not be transmitted to the compressor 3. , the compression pressure of the compressor 3 changes or becomes constant. On the other hand, if the electromagnetic clutch 5 is stuck, the power from the engine 2 continues to be transmitted to the compressor 3 even after the compressor 3 is instructed to stop. The compression pressure also changes. The electronic control unit 21 determines whether or not the electromagnetic clutch 5 is stuck by focusing on the temporal change relationship between the rotational speed of the engine 2 and the compression pressure of the compressor 3 as described above. .

Specifically, the electronic control unit 21 according to the present embodiment determines whether or not the electromagnetic clutch 5 is stuck using, for example, the following relational expression. That is, here, the rotation speed of the engine 2 detected at time t1 after the instruction to stop the compressor 3 is given is Ne(t1), and the compression pressure of the compressor 3 detected at time t1 is Pd( t1). Ne(t2) is the rotational speed of the engine 2 detected at time t2 after a predetermined time Δt has elapsed from time t1, and Pd(t2) is the compression pressure of the compressor 3 detected at time t2. do. Note that the predetermined time Δt is set (Δt∝p) so as to correspond to the detection period p of the rotation speed and the compression pressure. Then, when the relationship of the following expression (1) expressed using these parameters Ne(t1), Pd(t1), Ne(t2) and Pd(t2) is satisfied, the electronic control unit 21 performs electromagnetic It is determined that the clutch 5 is stuck.
(Pd(t2)-Pd(t1))/(Ne(t2)-Ne(t1))>0 (1)

That is, the electronic control unit 21 determines that the value of the left side of the above equation (1), that is, the ratio of the amount of change in the compression pressure of the compressor 3 to the amount of change in the rotation speed of the engine 2 in the predetermined time Δt becomes greater than zero. If it is, it is determined that the electromagnetic clutch 5 is stuck. Specifically, when the rotation speed of the engine 2 increases in the predetermined time Δt, the amount of change (Ne(t2)-Ne(t1)) becomes a positive value. At this time, if the electromagnetic clutch 5 is stuck, the compression pressure of the compressor 3 increases in conjunction with the increase in the rotation speed of the engine 2, and the amount of change (Pd(t2)-Pd(t1)) is also A positive value. Therefore, when the electromagnetic clutch 5 is stuck, the value of the left side of the above equation (1) is greater than zero. On the other hand, if the electromagnetic clutch 5 is in a normal state, the compression pressure of the compressor 3 does not increase even if the engine 2 speed increases, so the amount of change in compression pressure is 0 or a negative value. Therefore, when the electromagnetic clutch 5 is not stuck, the value of the left side of the above equation (1) is 0 or less.

Further, when the rotation speed of the engine 2 decreases in the predetermined time Δt, the amount of change (Ne(t2)-Ne(t1)) becomes a negative value. At this time, if the electromagnetic clutch 5 is stuck, the compression pressure of the compressor 3 also decreases in conjunction with the decrease in the rotation speed of the engine 2, and the amount of change (Pd(t2)-Pd(t1)) is also Negative value. Therefore, when the electromagnetic clutch 5 is stuck, the value of the left side of the above equation (1) is greater than zero. On the other hand, if the electromagnetic clutch 5 is in a normal state, the compression pressure of the compressor 3 does not decrease even if the rotation speed of the engine 2 decreases. Therefore, when the electromagnetic clutch 5 is not stuck, the value of the left side of the above equation (1) is 0 or less.

When the electronic control unit 21 determines that the electromagnetic clutch 5 is stuck as described above (YES in step S60), the process proceeds to the next step S70. On the other hand, when it is determined that the electromagnetic clutch 5 is not stuck (NO in step S60), the process proceeds to step S100.

In step S70, the electronic control unit 21 adjusts the rotational speed of the engine 2 so that the torque generated by the engine 2 is greater than the reference torque set corresponding to the state in which the electromagnetic clutch 5 of the compressor 3 is disengaged. is controlled. Normally, when the electromagnetic clutch 5 is disconnected in accordance with a stop instruction for the compressor 3, the load applied to the engine 2 is reduced as the compressor 3 stops. , control is performed to reduce the rotation speed of the engine 2 . However, in a situation where the electromagnetic clutch 5 is stuck, if the rotation speed is reduced by controlling the engine 2 corresponding to the state in which the electromagnetic clutch 5 of the compressor 3 is disconnected as described above, the engine 2 will be overloaded. state and the engine may stall.

Therefore, in the electronic control unit 21 according to the present embodiment, even after an instruction to stop the compressor 3 is given, in order to avoid the occurrence of the engine stall and to eliminate the sticking of the electromagnetic clutch 5, the A control signal is generated that controls the rotational speed of the engine 2 so that torque greater than the reference torque is generated. Note that the rotation speed of the engine 2 can be set by referring to a torque curve or the like representing the performance of the engine 2 . In this embodiment, even after the instruction to stop the compressor 3 is given, the rotation speed of the engine 2 is controlled so that the same torque as when the compressor 3 is operating before is generated.

The rotation speed of the engine 2 is adjusted according to the control signal from the electronic control unit 21, and when the engine 2 generates a torque larger than the reference torque, the torque is transmitted to the pulley 3a of the compressor 3 via the belt 4. , a force that causes slippage acts on the attracting surface F between the armature 5a and the pulley 3a. In particular, in the present embodiment, the rotational speed of the engine 2 is controlled so that the same torque as when the compressor 3 is operating is generated in the engine 2, so slipping on the attracting surface F is more likely to occur. Such continuous sliding on the attracting surface F makes it possible to separate the armature 5a and the pulley 3a from sticking (adhesion), if any. Further, when the contact portion of the relay 5c is stuck, heat is generated due to slippage on the attracting surface F, and the heat activates the thermal fuse 5d to cut off the current to the electromagnetic coil 5b. becomes possible.

In the next step S80, the electronic control unit 21 determines whether or not the stuck electromagnetic clutch 5 is released at predetermined time intervals. The electronic control unit 21 determines whether or not the electromagnetic clutch 5 is stuck, based on the fact that the temporal changes in the rotational speed of the engine 2 and the compression pressure of the compressor 3 no longer satisfy the above-described relationship (1). That is, when the value of the left side of the equation (1) (ratio of change in the compression pressure of the compressor 3 to change in the rotation speed of the engine 2 in the predetermined time Δt) is 0 or less, the electromagnetic clutch 5 is stuck. is resolved. In other words, when the compression pressure of the compressor 3 changes or becomes constant without interlocking with the change (increase or decrease) of the engine speed, it is determined that the electromagnetic clutch 5 is released.

If it is determined in step S80 that the electromagnetic clutch 5 is not fixed (NO), the process proceeds to step S90. In step S90, the electronic control unit 21 controls the rotational speed of the engine 2 so as to further increase the torque generated by the engine 2, and the process returns to step S80. The control of the rotational speed of the engine 2 in step S90 is repeated until it is determined in step S80 that the stuck electromagnetic clutch 5 is eliminated. In other words, the rotational speed of the engine 2 is controlled by the electronic control unit 21 so that the torque generated by the engine 2 gradually increases until it is determined that the stuck electromagnetic clutch 5 is released.

Then, when it is determined that the stuck electromagnetic clutch 5 is eliminated (YES in step S80), in step S100, the electronic control unit 21 controls the engine 2 so that the torque generated in the engine 2 becomes the above-described reference torque. The rotational speed is controlled, and the process returns to step S20.

While the electromagnetic clutch 5 is being determined to be stuck, a warning is displayed on the instrument panel in the passenger compartment R and on a monitor or the like to notify the occupant of the vehicle that the air conditioner is abnormal. It's good. If the electromagnetic clutch 5 is determined to be stuck for a certain period of time, it is determined that the electromagnetic clutch 5 has failed, and a warning is displayed to inform the passenger that the air conditioner has failed, or to prompt an investigation at a store or the like. You may do so.

By executing the series of processes of steps S10 to S100 as described above by the electronic control unit 21, the vehicle air conditioner 1 of the present embodiment can determine whether or not the electromagnetic clutch 5 is stuck with a simple configuration. , the torque generated by the engine 2 can be increased before the engine 2 stops due to an overload condition (engine stall). Due to such an increase in the torque of the engine 2, slippage tends to occur between the armature 5a and the attracting surface F of the pulley 3a. If the armature 5a and the pulley 3a are adhered (adhered) due to the slippage on the attracting surface F, the adherence can be removed and the electromagnetic clutch 5 can be disconnected. Further, when the contact portion of the relay 5c is stuck, the thermal fuse 5d is actuated to cut off the energization of the electromagnetic coil 5b, thereby disconnecting the electromagnetic clutch 5. FIG. Therefore, according to the vehicle air conditioner 1 of the present embodiment, it is possible to avoid the abnormal state of the compressor 3 due to the sticking of the electromagnetic clutch 5 and prevent the engine from stalling.

Further, in the vehicle air conditioner 1 of the present embodiment, when the compression pressure of the compressor 3 increases as the rotation speed of the engine 2 increases after the instruction to stop the compressor 3 is given in the electronic control unit 21, or when the rotation speed of the engine 2 When the compression pressure of the compressor 3 decreases as the number decreases, it is determined that the electromagnetic clutch 5 is stuck. As a result, it is possible to accurately determine whether or not the electromagnetic clutch 5 is stuck. In particular, if the determination is made using the relationship of formula (1) described above, it becomes possible to determine the presence or absence of sticking more accurately, and it is possible to accurately control the rotation speed of the engine 2. be possible. Therefore, it is possible to effectively prevent the engine from stalling due to the stuck electromagnetic clutch 5 .

Furthermore, in the vehicle air conditioner 1 of the present embodiment, after determining that the electromagnetic clutch 5 has become stuck, it is determined at predetermined time intervals whether or not the electromagnetic clutch 5 has become stuck. The rotation speed of the engine 2 is controlled so that the torque generated by the engine 2 gradually increases until it is determined that the sticking is eliminated. As a result, the attachment (adhesion) between the armature 5a and the pulley 3a can be reliably removed, or the temperature fuse 5d can be reliably actuated to cut off the energization of the electromagnetic coil 5b, thereby disconnecting the electromagnetic clutch 5. be possible. Therefore, it is possible to more effectively prevent the engine from stalling due to the stuck electromagnetic clutch 5 .

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes are possible based on the technical idea of the present invention. For example, in the above-described embodiment, an example in which the engine 2 is used as the driving machine for the compressor 3 has been described, but it is of course possible to use a motor or the like as the driving machine.

In the above-described embodiment, the electromagnetic clutch 5 (clutch portion) is configured such that the electromagnetic coil 5b is energized via the relay 5c and the thermal fuse 5d, and the magnetic force generated by the electromagnetic coil 5b causes the armature 5a to operate as a compressor. Although an example in which the clutch is attracted to the pulley 3a of 3 is shown, the configuration of the clutch portion is not limited to the above example, and the present invention is effective for any clutch that can be used to transmit power from the driving machine to the compressor. .

Furthermore, in the above-described embodiment, an example in which the electronic control unit 21 controls the on/off of the compressor 3 and the rotation speed of the engine 2 has been described. It may be controlled by unit 21 . For example, when the automatic air conditioning function is enabled, the electronic control unit 21 automatically controls the blowout temperature, the number of fan stages, and the switching of internal air circulation, making it possible to achieve more comfortable air conditioning control. Become.

DESCRIPTION OF SYMBOLS 1... Vehicle air conditioner 2... Engine 2a... Pulley 3... Compressor 3a... Pulley 3b... Bearing 3c... Hub 3d... Shaft 4... Belt 5... Electromagnetic clutch 5a... Armature 5b... Electromagnetic coil 5c... Relay 5d... Thermal fuse 6... Discharge-side hose 7 Condenser 8 Fan 9 Liquid pipe 10 Car air conditioner (HVAC)
DESCRIPTION OF SYMBOLS 11... Expansion valve 12... Evaporator 13... Suction side hose 21... Electronic control unit (ECU)
22... pressure sensor (PS)
23... rotation speed sensor (RS)
E... Power unit mounting room F... Adsorption surface G... Gap R... Vehicle room

Claims (5)

In a control method for a vehicle air conditioner equipped with a compressor to which power of a driving machine is transmitted via a clutch portion,
Detecting the rotation speed of the driving machine and detecting the compression pressure of the compressor corresponding to the rotation speed,
determining whether or not the clutch portion is stuck based on the detected change in the rotational speed of the driving machine and the change in the compression pressure of the compressor;
When it is determined that the clutch portion is stuck, even after an instruction to stop the compressor is given, the torque generated by the driving machine corresponds to the state in which the clutch portion of the compressor is disengaged. A control method for a vehicle air conditioner, comprising: controlling the number of revolutions of the driving machine so that it becomes larger than a reference torque set by the driver. Determination of whether or not the clutch portion is stuck is made when the compression pressure of the compressor rises as the number of rotations of the driving machine increases after an instruction to stop the compressor is given, or when the 2. The control method for a vehicle air conditioner according to claim 1, wherein, when the compression pressure of said compressor decreases as the number of revolutions of said driving machine decreases, it is determined that said clutch portion is stuck. . Determination of whether or not sticking occurs in the clutch portion is performed by:
Let Ne(t1) be the rotation speed of the driving machine detected at time t1 after the instruction to stop the compressor is given,
Let Pd(t1) be the compression pressure of the compressor detected at time t1,
Let Ne(t2) be the rotational speed of the driving machine detected at time t2 after a predetermined time Δt has elapsed from time t1,
Assuming that the compression pressure of the compressor detected at time t2 is Pd(t2), the relationship of the following equation,
(Pd(t2)-Pd(t1))/(Ne(t2)-Ne(t1))>0
3. The control method for a vehicle air conditioner according to claim 2, wherein it is determined that the clutch portion is stuck when the condition is satisfied. determining, at predetermined time intervals after determining the occurrence of sticking of the clutch portion, whether or not the sticking of the clutch portion has been eliminated;
Until it is determined that the fixation of the clutch portion is eliminated, the rotation speed of the driving machine is controlled so that the torque generated by the driving machine gradually increases. 4. The method for controlling a vehicle air conditioner according to any one of 3. A vehicle air conditioner equipped with a compressor to which the power of a driving machine is transmitted via a clutch unit,
a detection unit that detects the rotation speed of the driving machine and detects the compression pressure of the compressor that corresponds to the rotation speed;
a determination unit that determines whether or not the clutch unit is stuck based on changes in the rotation speed of the driving machine and changes in the compression pressure of the compressor detected by the detection unit;
When the determining unit determines that the clutch portion is stuck, the torque generated by the driving machine is such that the clutch portion of the compressor is cut off even after an instruction to stop the compressor is given. a control unit that controls the rotation speed of the driving machine so that it becomes larger than a reference torque that is set corresponding to the state of
A vehicle air conditioner, comprising:

Images