Compressor control apparatus and method

A compressor control apparatus and method includes: a sensor configured to detect air conditioner operation state information necessary to control engagement and disengagement of a clutch of an air conditioner compressor; an electromagnetic coil in the clutch of the air conditioner compressor configured to perform clutch engagement upon receiving battery current; a microcomputer configured to determine whether the current air conditioner operation state satisfies a clutch engagement allowance condition or a clutch disengagement condition based on the air conditioner operation state information detected by the sensor and to output an operation signal based on the result of determination; and a switch configured to be turned on or off according to the operation signal output by the microcomputer and to control supply of the battery current to the electromagnetic coil such that clutch engagement or clutch disengagement is performed.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims, under 35 U.S.C. § 119(a), the benefit of priority to Korean Patent Application No. 10-2021-0036395 on Mar. 22, 2021, the entire contents of which are incorporated herein by reference.

BACKGROUND

(a) Technical Field

The present disclosure relates to a compressor control apparatus and a method, and more particularly to a compressor control apparatus and a method capable of simplifying the construction of a compressor control circuit, reducing the number of parts, and reducing costs.

(b) Background Art

In general, a vehicle is equipped with an air conditioning apparatus configured to heat or cool the interior of the vehicle. The air conditioning apparatus constantly maintains the temperature in the interior of the vehicle at the optimum temperature, irrespective of a change in temperature of external air and thus provides a comfortable interior environment.

An air conditioning apparatus for vehicles includes an air conditioner system configured to circulate a refrigerant. The air conditioner system mainly includes a compressor configured to compress a refrigerant, a condenser configured to condense the refrigerant compressed by the compressor so as to be liquefied, an expansion valve configured to expand the refrigerant liquefied as the result of being condensed by the condenser, and an evaporator configured to evaporate the refrigerant expanded by the expansion valve and to cool air blown to the interior of the vehicle using latent heat of evaporation of the refrigerant.

In the air conditioner system, the high-temperature and high-pressure gaseous refrigerant compressed by the compressor is condensed by the condenser into a liquid state and is circulated to the compressor via the expansion valve and the evaporator in a cooling mode in summer. In this process, the low-temperature and low-pressure liquid refrigerant expanded by the expansion valve is supplied to the evaporator and is air cooled through heat exchange with the refrigerant evaporated by the evaporator. The expanded and cooled air is discharged to the interior of the vehicle, and thus interior cooling is achieved.

Meanwhile, in the vehicle, control of the air conditioner compressor and supply of power to the air conditioner compressor are performed by a controller and a relay switch in a junction box. In addition, the component of the air conditioner system of the vehicle configured to selectively operate the compressor using power from a battery is a clutch of the compressor.

FIG.1is a view showing the construction of a conventional compressor control apparatus.FIG.1shows a control circuit configured to control the operation of a compressor30, wherein the control circuit includes a controller10, a relay switch20, and a clutch31of the compressor30.

The clutch31of the compressor30is provided with an electromagnetic coil32. The clutch31connects the compressor30and an engine (not shown) such that power transmission is possible using magnetomotive force induced by current. In other words, when the air conditioner is turned on, the clutch31of the compressor30is engaged by the controller10, whereby rotational force of an engine crankshaft (not shown) transmitted to a pulley (not shown) of the compressor30is transmitted to a compressor shaft (not shown). Therefore, the compressor30, which is configured to compress a refrigerant, is operated by engine rotation force.

The relay switch20is configured to selectively supply current of a battery9to the clutch31of the compressor30. The relay switch20is turned on according to an operation signal (relay driving signal) output by the controller10and controls the supply of power to the electromagnetic coil32of the clutch31such that the operation of the compressor30is controlled.

At this time, the controller10determines whether to operate the compressor in consideration of compressor operation conditions and external conditions and transmits an operation signal to the relay switch20. In other words, the coil side of the relay switch20is excited according to the operation signal, whereby the contact side of the relay switch20is closed and thus current of the battery9is applied to the electromagnetic coil32of the clutch31via the contact side.

When the current is applied to the electromagnetic coil32, as described above, the clutch is engaged by magnetic force of the electromagnetic coil32. Therefore, the engine rotation force transmitted to the pulley is transmitted to the compressor shaft and thus the compressor30is operated. In addition, when the operation signal (excitation current) is not applied to the coil side of the relay switch20and the contact side is opened. Thus, current of the battery9does not flow to the electromagnetic coil32of the clutch31and magnetic force of the electromagnetic coil is lost. Therefore, the clutch is disengaged and thus connection between the engine and the compressor is released.

In addition, diodes21and33configured to solve a surge voltage (back electromagnetic force) problem at the time of clutch disengagement are installed at the relay switch20and the clutch31, respectively. The controller10outputs only a signal for compressor operation (clutch engagement) and non-operation (clutch disengagement) and the relay switch20controls a power supply path (through opening and closing of the contact side of the relay switch) to control the compressor30.

At this time, a diode21and a ground wire22configured to reduce sparks occurring at the relay switch20and opening and closing-based surge voltage occurring at the front and rear ends of the contact side of the relay switch are necessary. In addition, it is necessary to provide a diode33and a circuit configured to remove back electromagnetic force due to current fluctuation when the relay switch is opened and closed at the clutch31of the compressor30, which complicates the construction of the circuit.

SUMMARY OF THE DISCLOSURE

The present disclosure has been made in an effort to solve the above-described problems associated with the prior art.

It is an object of the present disclosure to provide a compressor control apparatus and a method capable of simplifying the construction of a compressor control circuit, reducing the number of parts, and reducing costs.

The objects of the present disclosure are not limited to those described above. Other unmentioned objects of the present disclosure should be clearly understood by a person of ordinary skill in the art (hereinafter referred to as an “ordinary skilled person”) from the following description.

In order to accomplish the object, in an aspect, the present disclosure provides a compressor control apparatus including a sensor configured to detect air conditioner operation state information necessary to control engagement and disengagement of a clutch of an air conditioner compressor. The compressor control apparatus also includes an electromagnetic coil in the clutch of the air conditioner compressor configured to perform clutch engagement upon receiving battery current. The compressor control apparatus also includes a microcomputer configured to determine whether the current air conditioner operation state satisfies a clutch engagement allowance condition or a clutch disengagement condition based on the air conditioner operation state information detected by the sensor and to output an operation signal based on the result of determination. The compressor control apparatus also includes a switch configured to be turned on or off according to the operation signal output by the microcomputer and to control supply of the battery current to the electromagnetic coil such that clutch engagement or clutch disengagement is performed.

In another aspect, the present disclosure provides a compressor control method including detecting, by a sensor, air conditioner operation state information necessary to control engagement and disengagement of a clutch of an air conditioner compressor. The compressor control method also includes determining, by a microcomputer, whether the current air conditioner operation state satisfies a clutch engagement allowance condition or a clutch disengagement condition based on the air conditioner operation state information detected by the sensor and outputting an operation signal based on the result of determination. The compressor control method also includes turning on or off a switch configured to control supply of battery current to an electromagnetic coil in the clutch according to the operation signal output by the microcomputer such that clutch engagement or clutch disengagement is performed.

Other aspects and embodiments of the present disclosure are discussed below.

It should be understood that the appended drawings are not necessarily to scale and present a somewhat simplified representation of various features illustrating the basic principles of the present disclosure. The specific design features of the present inventive concept as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes, are determined in part by the particular intended application and use environment.

DETAILED DESCRIPTION

Specific structural or functional descriptions of the embodiments of the present inventive concept disclosed in this specification are given only to illustrate embodiments of the present disclosure. Embodiments of the present disclosure may be realized in various forms. In addition, the embodiments according to the concept of the present disclosure are not limited to such specific embodiments. It should be understood that the present disclosure includes all alterations, equivalents, and substitutes that fall within the idea and technical scope of the present disclosure.

It should be understood that, although the terms “first”, “second”, etc. may be used herein to describe various elements, corresponding elements should not be understood as being limited by these terms, which are used only to distinguish one element from another. For example, within the scope defined by the present disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

It should be understood that, when a component is referred to as being “connected to” or “coupled to” another component, it may be directly connected to or coupled to the other component, or intervening components may be present. In contrast, when a component is referred to as being “directly connected to” or “directly coupled to” another component, there are no intervening components present. Other terms that describe the relationship between components, such as “between” and “directly between” or “adjacent to” and “directly adjacent to”, are to be interpreted in the same manner.

Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like parts. The terms used in this specification are provided only to explain specific embodiments but are not intended to restrict the present disclosure. A singular representation may include a plural representation unless it represents a definitely different meaning from the context. It should be further understood that the terms “comprises”, “comprising” and the like, when used in this specification, specify the presence of stated components, steps, operations, and/or elements but do not preclude the presence or addition of one or more other components, steps, operations, and/or elements. When a component, device, element, or the like of the present disclosure is described as having a purpose or performing an operation, function, or the like, the component, device, or element should be considered herein as being “configured to” meet that purpose or to perform that operation or function.

The present disclosure relates to a compressor control apparatus and a method capable of simplifying the construction of a compressor control circuit, reducing the number of parts, and reducing costs. In the present disclosure, a circuit is simplified and optimized, compared to the conventional art by using a switch in a controller at the rear side of a load end (an electromagnetic coil of a compressor clutch) as a circuit opening and closing means for compressor control, instead of removing a relay switch in a junction box for compressor operation and a circuit related thereto.

Also, in the present disclosure, circuit opening and closing for clutch power supply control is directly performed in a controller, i.e., an engine control unit (ECU) and the controller determines whether clutch engagement is possible and directly controls clutch operation.

To this end, the resistance value and the power value of the compressor clutch (electromagnetic coil of the clutch) allowable by the controller must be selected and logic for determining and solving a problem in that the current value becomes an allowable value (current limit) or more and reoperating the compressor is necessary. In addition, it is necessary to add logic for estimating the temperature at which the resistance value of the clutch reaches a lower limit and determining whether clutch engagement is possible in order to secure circuit stability and to extend an actually possible engagement range.

Hereinafter, an embodiment of the present disclosure is described in detail with reference to the accompanying drawings.FIG.2is a view showing the construction of a control apparatus according to an embodiment of the present disclosure. In the present disclosure, the relay switch20for the compressor clutch in the junction box and the diode21for surge voltage prevention are removed from the conventional control circuit (seeFIG.1) and the diode33is also removed from the clutch31of the compressor30.

Instead, as shown inFIG.2, in the present disclosure includes a switch12provided in a controller (ECU)10so as to control the supply of power to a clutch31of a compressor30and to open and close a circuit. In other words, the supply of power to the clutch31of the compressor30is controlled using the switch12in the controller10. Here, a portion of the clutch31of the compressor30to which power is supplied, i.e. a load portion, is an electromagnetic coil32.

In the embodiment of the present disclosure, the switch12may be a switching element configured to be opened and closed according to an operation signal output by a microcomputer11of the controller10or may be a semiconductor switch, such as a metal oxide semiconductor field effect transistor (MOSFET).

A vehicle is equipped with an ignition (IG2) power end1, which is turned on (IG2on) at the time of key on. In the present disclosure, the electromagnetic coil32of the clutch31is directly connected to the ignition power end1of the vehicle. Consequently, the electromagnetic coil32is connected to battery power B+ via the ignition power end1of the vehicle. In the case in which the electromagnetic coil32is connected to the battery power B+ via the ignition power end1of the vehicle, as described above, it is possible to prevent battery discharge due to short circuit in a key off state.

In the case in which a battery9and the electromagnetic coil32of the clutch31, which is a load, are directly connected to each other via a circuit, as in the embodiment ofFIG.2, the battery may be discharged. In the present disclosure, therefore, the ignition power end1is disposed between the battery power B+ and the electromagnetic coil32of the clutch31such that current of the battery9is supplied only in the key on state.

In other words, the electromagnetic coil32of the clutch31is connected to the ignition power end1such that the electromagnetic coil of the clutch is connected to the battery power B+ via the ignition power end. A circuit of the ignition power end is closed only in the key on (i.e. IG2on) state, whereby the battery power B+, which is vehicle power, is supplied to the load in the vehicle. In other words, current of the battery9flows to the electromagnetic coil32of the clutch31via the ignition power end1only in the key on state.

Of course, when current of the battery9flows to the electromagnetic coil32, clutch engagement is performed, whereby engine rotation force transmitted to a pulley is transmitted to a compressor shaft. Therefore, the compressor30compresses a refrigerant. Since an air conditioner is operated only in the key on (i.e. IG2on) state, there is no problem in connecting the electromagnetic coil32of the clutch31, which is a load, to the ignition power end1.

In addition, the electromagnetic coil32of the clutch31is connected one terminal of the switch12in the controller10and the other terminal of the switch12in the controller10is connected to a ground end13. In other words, a circuit is formed so as to form an electrical conduction path of the battery9→the ignition power end1→the clutch31of the compressor30(electromagnetic coil)→the switch12in the controller (ECU)10→the ground end13.

Since the battery power B+ is connected to the electromagnetic coil32of the clutch31via the ignition power end1and the electromagnetic coil32of the clutch31is connected to the ground end13via the switch12in the controller10, as described above, the switch12in the controller10is turned off by the microcomputer11when the air conditioner is turned off. Thus, no current flows to the electromagnetic coil32of the clutch31.

In the present disclosure, when current of the battery9flows to the electromagnetic coil32of the clutch31, clutch engagement is performed. When current of the battery9does not flow to the electromagnetic coil32of the clutch31while the vehicle is driven, the clutch31is disengaged. In the following description, clutch engagement means a clutch coupling state in which power transmission is possible and clutch disengagement means a clutch decoupling state in which no power is transmitted between opposite ends of the clutch.

When the air conditioner is turned on, on the other hand, an operation signal output by the microcomputer11of the controller (ECU)10is transmitted to the switch12in the controller and thus the switch in the controller is closed. At this time, current of the battery9sequentially passes through the IG power end1, the electromagnetic coil32of the clutch31, and the switch12in the controller10, and then flows to the ground end13connected to the controller.

As the current is applied to the electromagnetic coil32of the clutch31, as described above, clutch engagement is performed, and engine rotation force transmitted to the pulley (not shown) is transmitted to the compressor shaft (not shown) in the clutch engagement state, whereby the refrigerant is compressed by the compressor30.

In the air conditioner off state, the switch12in the controller10is maintained off (open) by the microcomputer11of the controller (ECU)10.

In the air conditioner on state, the switch12in the controller10is turned on according to an operation signal output by the microcomputer11of the controller. In other words, when the switch12in the controller10is turned on, the clutch engagement is performed, the compressor30is turned on, and the air conditioner is turned on. When the switch12in the controller10is turned off, the clutch disengagement is performed, the compressor30is turned off, and the air conditioner is turned off.

When the switch12in the controller10is turned off again while current flows in the state in which the switch is on, an instantaneous voltage difference occurs between the front and rear ends of the switch, whereby surge voltage or sparks may occur. In order to remove this, a reduction element installed in the controller10so as to be connected to the switch via a circuit, such as a common diode, may be used.

Since surge voltage or sparks are removed using the switch side reduction element in the controller, as described above, it is possible to remove a reduction element installed at the conventional junction box and load side. In the case in which the capacity of the reduction element in the controller is insufficient, however, a diode configured to inhibit occurrence of surge voltage or sparks may be added to the load end (clutch side).

Meanwhile, as can be seen fromFIG.2, in the state in which the switch12in the controller10is on, current that flows along the electromagnetic coil32of the clutch31flows to the ground end13via the switch12in the controller10. At this time, a current limit value is set in the microcomputer11such that current having a predetermined value or more does not flow to the interior of the controller10and the switch12.

In other words, the microcomputer11of the controller10monitors operation current that flows to the interior of the controller10and the switch12after passing through the electromagnetic coil32of the clutch31through a sensor. When the operation current is equal to or greater than the current limit value, i.e. overcurrent, the microcomputer11keeps the switch12in the controller10off. The state in which the switch in the controller is off means the clutch disengagement state and the air conditioner off state.

Hereinafter, a compressor control method according to an embodiment of the present disclosure is described in detail.FIGS.3A and3Bare flowcharts showing compressor clutch operation condition determination logic in a control method according to an embodiment of the present disclosure.FIG.4is a view showing an example of set data in which the temperature of the clutch is set depending on the pressure of the refrigerant in the control method according to the embodiment of the present disclosure. The clutch operation condition determination logic ofFIGS.3A and3Bis performed by the microcomputer11of the controller10.

The value of current that flows in the electromagnetic coil32of the clutch31is changed depending on the value of resistance of the electromagnetic coil and the value of voltage of the battery9. In addition, the value of resistance of the electromagnetic coil32is changed depending on the temperature of the electromagnetic coil. In other words, the value of resistance of the electromagnetic coil32is small when the temperature of the electromagnetic coil is low.

In addition, the value of current that flows in the electromagnetic coil32of the clutch31is large when the temperature of the electromagnetic coil, which acts as resistance, is low or the value of voltage of the battery is large. In other words, when the temperature of the electromagnetic coil is low or the value of voltage of the battery is large, a large amount of current flows in the electromagnetic coil. Hereinafter, the current that passes through the electromagnetic coil of the clutch is referred to as “operation current.”

In general, the temperature of the electromagnetic coil is the temperature of the clutch and the clutch has no sensor configured to detect the temperature of the electromagnetic coil. In the present disclosure, therefore, the temperature of the electromagnetic coil, i.e. the temperature of the clutch, is converted from the pressure of the air conditioner refrigerant detected by a refrigerant pressure sensor2and a clutch engagement allowance condition may be determined based on the converted temperature of the clutch.

In other words, as shown inFIG.3A, in the case in which, in a compressor clutch disengagement state (S1), the converted temperature of the clutch (temperature of the electromagnetic coil) is compared with a first set temperature (e.g. −10° C.) (S2) and is higher than the first set temperature, the value of resistance of the electromagnetic coil32increases. Thus, the operation current becomes less than the current limit. At this time, the microcomputer11of the controller10may determine the current condition to be a clutch engagement allowance condition (S5).

In the case in which the converted temperature of the clutch31is equal to or lower than the first set temperature in step S2, on the other hand, the value of resistance of the electromagnetic coil32decreases, whereby the operation current may become equal to or greater than the current limit. Consequently, the microcomputer11of the controller10may determine the current condition to be a clutch disengagement condition (S3).

In addition, as shown inFIG.3A, in the case in which, in the state in which the current condition is determined to be a clutch disengagement condition, the converted temperature of the clutch31(temperature of the electromagnetic coil) is compared with a second set temperature (e.g. −5° C.) (S4) and is higher than the second set temperature, the microcomputer11of the controller10may determine the current condition to be a clutch engagement allowance condition (S5).

In the controller10, the first set temperature and the second set temperature may be set so as to have a relationship of second set temperature>first set temperature. The reason for this is that it is necessary to set a hysteresis period in determining whether the current condition is a clutch engagement allowance condition or a clutch disengagement condition based on the converted temperature of the clutch.

In the embodiment of the present disclosure, the microcomputer11of the controller10may use data in which the temperature of the clutch is set based on the pressure of the refrigerant, as shown inFIG.4, in order to calculate the temperature of the clutch31from the pressure of the air conditioner refrigerant detected by the refrigerant pressure sensor2. The set data shown inFIG.4are obtained using data acquired through prior research and evaluation tests. The example ofFIG.4shows a map that defines a relationship between the pressure of the refrigerant and the temperature of the clutch. However, a table or formula that defines a relationship between the pressure of the refrigerant and the temperature of the clutch may be used in addition to the map.

In the map ofFIG.4, the temperature of the clutch based on the pressure of the refrigerant may be represented by Equation 1 below. In the present disclosure, clutch temperature Tclutchmay be calculated from refrigerant pressure p using Equation 1 below, which is a linear equation.
f(p)=Tclutch=A×p+B[Equation 1]

In the case in which Equation 1 above is used, values of A and B are preset by the microcomputer of the controller.

In the present disclosure, as described above, the temperature of the clutch is converted from the pressure of the refrigerant using set data in which a relationship between the clutch temperature Tclutchand refrigerant pressure p is defined. Whether the current condition is a clutch engagement allowance condition or a clutch disengagement condition is determined based on the converted temperature of the clutch.

In the above description, the microcomputer11of the controller10compares the temperature of the clutch with the first set temperature in order to determine whether the current condition is a clutch engagement allowance condition or a clutch disengagement condition. Here, the temperature of the clutch is converted from the pressure of the refrigerant detected by the refrigerant pressure sensor2and the temperature of the clutch and the pressure of the refrigerant increase and decrease in proportion to each other, as shown inFIG.4. Consequently, the pressure of the refrigerant detected by the refrigerant pressure sensor2may also be compared with the set pressure for determination instead of comparison between the temperature of the clutch and the set temperature.

In other words, as shown inFIG.3B, in the case in which, in a clutch disengagement state, the pressure of the refrigerant detected by the refrigerant pressure sensor2is compared with a predetermined first set pressure (S2′) and the detected pressure of the refrigerant is higher than the first set pressure, the microcomputer11may be set to determine that a clutch engagement allowance condition is satisfied (S5). On the other hand, in the case in which, in a clutch disengagement state, the pressure of the refrigerant detected by the refrigerant pressure sensor2is equal to lower than the first set pressure, the microcomputer11may be set to determine that a clutch disengagement condition is satisfied (S3).

Also, in the state in which the current condition is determined to be a clutch disengagement condition, the pressure of the refrigerant detected by the refrigerant pressure sensor2is compared with a predetermined second set pressure (S4′) and the detected pressure of the refrigerant is higher than the second set pressure. In the above case, the microcomputer11may be set to determine that a clutch engagement allowance condition is satisfied (S5).

In the microcomputer11of the controller10, the first set pressure and the second set pressure may be set so as to have a relationship of second set pressure>first set pressure. Here, the first set pressure may be a pressure value having a relationship of Equation 1 andFIG.4with the first set temperature and the second set pressure may be a pressure value having a relationship of Equation 1 andFIG.4with the second set temperature.

In addition, the compressor control method according to the embodiment of the present disclosure includes a control method for reoperating the compressor30in an overcurrent off state of the compressor.FIG.5is a flowchart showing an air conditioner compressor reoperation logic in the control method according to the embodiment of the present disclosure. The air conditioner compressor reoperation logic shown inFIG.5may be performed by the microcomputer11of the controller10.

Basically, in an overcurrent condition in which the value of operation current that flows in the electromagnetic coil32of the clutch31is equal to or greater than the current limit value set by the controller, the microcomputer11of the controller10turns off the switch12in the controller to disengage the clutch and performs control such that the compressor and the air conditioner are turned off.

Also, in the case in which the converted temperature of the clutch31is equal to or lower than the first set temperature and the current condition is determined to be a clutch disengagement condition in the compressor clutch operation condition determination logic ofFIG.3A, the microcomputer11of the controller10turns off the switch12in the controller to disengage the clutch31and performs control such that the compressor and the air conditioner are turned off.

More specifically, in the embodiment of the present disclosure, upon determining that a predetermined reoperation condition is satisfied and at the same time the current condition is a clutch engagement allowance condition, the controller10reoperates the compressor. Here, the overcurrent off state of the compressor30may include a state in which the switch12is turned off by the controller10and thus the clutch31is disengaged and the compressor30is turned off in the overcurrent condition in which the value of operation current that flows in the electromagnetic coil32of the clutch31is equal to or greater than the current limit value set by the controller10.

In addition, the overcurrent off state of the compressor30may include a state in which the switch12is turned off by the controller10. Thus, the clutch31is disengaged and the compressor30is turned off in the case in which the converted temperature of the clutch31is equal to or lower than the first set temperature and the current condition is determined to be a clutch disengagement condition in the compressor clutch operation condition determination logic ofFIG.3A.

In addition, the set reoperation condition may include a condition in which the reoperation of the compressor is not the first operation of the compressor after starting of the vehicle. The set reoperation condition may also include a condition in which the air conditioner is on (air conditioner switch on), and a condition in which the temperature of an evaporator detected by an evaporator temperature sensor (thermistor)3is equal to or higher than a predetermined critical freezing temperature. In addition, the set reoperation condition may also include a condition in which the pressure of the air conditioner refrigerant detected by the refrigerant pressure sensor2is within a predetermined pressure range.

In the embodiment of the present disclosure, in the case in which the set reoperation condition is satisfied in the overcurrent off state of the compressor30, the controller10starts a control process for reoperation of the air conditioner compressor shown inFIG.5.

In other words, in the embodiment of the present disclosure, the microcomputer11of the controller10determines whether all of the conditions are satisfied in the overcurrent off state of the compressor30(S11). Such conditions include the condition in which the reoperation of the compressor is not the first operation of the compressor after starting of the vehicle, the condition in which the air conditioner is on (air conditioner switch on), the condition in which the temperature of the evaporator is equal to or higher than the predetermined critical freezing temperature, and the condition in which the pressure of the air conditioner refrigerant is within the predetermined pressure range. Upon determining that all of the conditions are satisfied, the microcomputer11of the controller10starts the control process ofFIG.5.

In the condition in which the temperature of the evaporator detected by the evaporator temperature sensor3is equal to or higher than the critical freezing temperature, as described above, the microcomputer11of the controller10reoperates the compressor30. In the condition in which the temperature of the evaporator is lower than the critical freezing temperature, as described above, the compressor30is not reoperated, since the evaporator may be frozen.

In addition, the microcomputer11of the controller10reoperates the compressor30in the condition in which the pressure of the refrigerant is within the pressure range and does not reoperate the compressor in the case in which the pressure of the refrigerant deviates from the pressure range.

In the case in which all of the conditions are satisfied, the microcomputer11of the controller10determines whether a failure diagnosis delay time set so as to correspond to the temperature of external air detected by an external air temperature sensor4elapses (S12). When the failure diagnosis delay time elapses, the microcomputer11of the controller10performs the clutch operation condition determination process ofFIG.3A or3B(S13).

Here, the failure diagnosis delay time may be set as shown in Table 1 below and the microcomputer11of the controller10determines the failure diagnosis delay time corresponding to the current temperature of external air using set data shown in Table 1 below.

In the example of Table 1 above, the failure diagnosis delay time in an intermediate section between 35° C. and −10° C., each of which is the temperature of external air, may be set to a value calculated by interpolation.

When the failure diagnosis delay time elapses, the microcomputer11of the controller10performs the clutch operation condition determination process ofFIG.3A or3B(S13). Upon determining in steps S2and S5ofFIG.3A or3Bthat the current condition is a clutch operation allowance condition, the microcomputer11of the controller10outputs an operation signal for turning on the switch12in the controller10. As a result, the switch12in the controller10is turned on, whereby clutch engagement is performed (S14) and the compressor is reoperated.

Subsequently, the microcomputer11of the controller10monitors operation current that flows in the electromagnetic coil32of the clutch31during operation of the compressor30and compares the monitored operation current with the current limit (S15). The microcomputer11maintains the on state of the switch12in the controller10, the engaged state of the clutch31, and the operation state of the compressor30in the state in which the value of the operation current is less than the current limit value

On the other hand, in the case in which the clutch operation condition determination process ofFIG.3A or3Bis performed in step S13ofFIG.5and the current condition is determined to be a clutch disengagement condition in step S2ofFIG.3Aor steps S2′ and S3ofFIG.3B, the microcomputer11of the controller10maintains the off state of the switch12in the controller10, the disengaged state of the clutch31, and the off state of the compressor30.

Also, in the case in which the value of the operation current is equal to or greater than the current limit value in step S15ofFIG.5during operation of the compressor30, the microcomputer11of the controller10turns off the switch12in the controller10and disengages the clutch31in order to turn off the compressor30again (S16).

The compressor control apparatus and method according to the present disclosure have been described above. In the compressor control apparatus and method according to the present disclosure, it is possible to remove a relay switch in a conventional junction box configured to selectively apply battery current to the compressor clutch and a diode configured to prevent surge voltage and to remove a circuit and wiring related thereto.

In addition, a diode configured to remove back electromagnetic force and surge voltage due to current fluctuation when the relay switch is opened and closed may be removed from the clutch of the compressor, which becomes a load end, and a circuit and wiring related thereto may be removed. In addition, it is possible to reduce cost and apparatus failure probability through reduction in number of parts and so simplification of circuit construction.

As is apparent from the foregoing, in the compressor control apparatus and method according to the present disclosure, it is possible to simplify the construction of a compressor control circuit, to reduce the number of parts and to reduce costs. Specifically, it is possible to remove a relay switch in a conventional junction box configured to selectively apply battery current to the clutch of the air conditioner compressor and a diode configured to prevent surge voltage and to remove a circuit and wiring related thereto. In addition, a diode configured to remove back electromagnetic force and surge voltage due to current fluctuation when the relay switch is opened and closed may be removed from the clutch of the compressor, which becomes a load end, and a circuit and wiring related thereto may be removed.

The effects of the present disclosure are not limited to those mentioned above. Other unmentioned effects should be clearly understood by an ordinary skilled person from the above description.

It should be apparent to a person of ordinary skill in the art that the present disclosure described above is not limited to the above embodiments and the accompanying drawings and that various substitutions, modifications, and variations can be made without departing from the technical idea of the present disclosure.