KR101501781B1 - Control method of air conditioner for vehicle - Google Patents

Abstract

The present invention relates to a control method of a vehicle air conditioning system for forcibly controlling an ECV duty to a constant value at the time of initial driving of a vehicle with a large engine rotation speed in vehicle cooling control using a vehicle air conditioning system. The present invention relates to a vehicle cooling control system using a vehicle air conditioning system, comprising: (A) comparing a coolant temperature of an engine with a set temperature; (B) variable-outputting the ECV duty when the cooling water temperature is higher than the set temperature; (C) Forcibly outputting the ECV duty constant to the set duty if the cooling water temperature is lower than the set temperature. According to the present invention, there is an advantage that a flow of engine revolution at the initial stage of driving the vehicle is reduced and a more stable driving environment can be provided.

Compressor, ECV duty, coolant temperature, engine speed

Description

[0001] The present invention relates to a control method of an air conditioner for a vehicle,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a control method for a vehicle air conditioner, and more particularly, to a vehicular air conditioner control method for controlling a vehicle air conditioner using a vehicle air conditioner, To a control method of the control unit.

1, a variable capacity compressor 11, which is driven by an engine 10 to compress a refrigerant and whose discharge amount is changed according to a cooling demand amount, A condenser 12 for condensing the refrigerant flowing through the condenser 12, and a condenser 12 for condensing the condensed refrigerant to a state where the refrigerant liquefied by the condenser 12 is thermally expanded to mix the gas and the liquid, An evaporator 14 for cooling the ambient air using the latent heat of evaporation when the refrigerant is vaporized and then returning the refrigerant to the compressor 11, And a control unit 20 for controlling the refrigerant discharge amount of the compressor 11 according to the air conditioning environment such as the indoor temperature and the outdoor temperature inputted from the user and the air conditioning condition inputted by the user.

When the air conditioner configured as described above is operated, the controller 20 controls the air conditioner environment such as the room temperature and the outdoor temperature transmitted from various sensors, the air conditioner conditions The refrigerant discharge amount of the compressor 11 is changed according to the amount of the refrigerant discharged from the compressor 11.

The refrigerant discharged from the compressor (11) condenses and liquefies through the condenser (12), and the gas and the liquid are mixed while passing through the electronic expansion valve (13). At this time, the degree of opening of the electronic expansion valve 13 changes according to the refrigerant discharge amount of the compressor 11.

Thereafter, the refrigerant flowing into the evaporator 14 is vaporized, and the surrounding air is cooled through heat exchange with the surrounding air. That is, since the latent heat of vaporization required to vaporize the refrigerant is taken from the surrounding air, the temperature of the ambient air of the evaporator 14 is lowered.

The vaporized refrigerant flows into the compressor (11) again, and the cooled air is supplied to the room through the heat exchange to cool the room. At this time, a temperature sensor 21 for sensing the temperature of the air is installed on the outlet side of the evaporator 14. When the temperature of the outlet side of the evaporator is lower than a predetermined temperature, the controller 20 controls the compressor 10 11) to shut off the operation of the compressor (11) by turning off the clutch (22). This is to prevent the water vapor contained in the air from being frozen in a state of being condensed in the evaporator 14 to inhibit heat exchange.

When the clutch 22 is turned off, the power transmission to the compressor 11 is interrupted and the rotation of the compressor 11 is stopped. Accordingly, when the temperature of the evaporator outlet is lowered below a specific temperature that stops the operation of the compressor 11, the clutch 22 is turned off, the operation of the compressor 11 is stopped, and the circulation of the refrigerant is stopped .

When the circulation of the refrigerant is stopped, heat exchange occurs between the evaporator 14 and the surrounding air, so that the evaporator outlet temperature gradually rises. When the evaporator outlet temperature rises above the limit temperature, the clutch 22 is connected, 11 are operated. Of course, when the compressor 11 is operated again, the temperature of the evaporator outlet is lowered, so that the above process can be repeated.

In the above-described air conditioner, the variable capacity swash plate type compressor 11 generally uses a pressure control valve for adjusting the inclination angle of the swash plate to control the amount of refrigerant discharge. In recent years, a swash plate type regulating valve (Hereinafter referred to as "ECV").

Therefore, in the case of the variable displacement swash plate compressor employing the ECV, the slope of the swash plate is changed by the duty of the ECV or the applied current value to the ECV, and the refrigerant discharge amount of the compressor is determined according to the slope of the swash plate.

As a result, the amount of refrigerant supplied to the evaporator changes depending on the duty of the ECV or the applied current value, which means that the duty or the applied current value of the ECV is a main factor for determining the evaporator temperature (hereinafter, 0 "). ≪ / RTI >

The above-mentioned ECV duty is a value representing the time during which the ECV is on during the whole time as a percentage. Therefore, when the duty is high, refrigerant discharge of the compressor increases, and when the duty is low, the refrigerant discharge decreases.

On the other hand, it is common to adjust the ECV duty to a variable control method, such as proportional-integral control, in order to keep the evaporator temperature at the target temperature and keep the internal temperature of the vehicle at a desired temperature. In such a case, when the required compressor torque changes rapidly according to the variation of the ECV duty, the engine speed may flow.

Particularly, when cooling the interior of the vehicle by using an air conditioner at the beginning of driving the vehicle, since the cooling water temperature of the engine is lowered to the outside temperature of the vehicle, the engine rotation speed is increased until the cooling water temperature rises and stabilizes , And the engine speed is normalized as the cooling water temperature of the engine becomes stable.

That is, in the ideal air conditioner control, as shown in FIG. 2, the engine speed RPM is lowered as the coolant temperature rises, and converges to the engine speed target engine speed when the coolant temperature is stable after the start of the vehicle.

At this time, since the compressor torque does not change suddenly, the engine rotation does not flow, and therefore, the ECV duty can also be constantly output.

However, as shown in FIG. 3, in the actual air conditioner control, as the ECV duty is variably controlled, the torque of the compressor changes to cause the engine speed to flow.

Particularly, since the fluctuation range of the engine speed is large during the decrease of the engine speed due to the rise of the cooling water temperature, the change of the engine speed varies with the change of the compressor torque, as compared with the case where the cooling water temperature is stable and the change of the engine speed is small.

Accordingly, the engine speed is changed so that the variation of the engine speed is transmitted to the driver through the steering wheel.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a method for controlling a vehicle air conditioning system capable of minimizing changes in the engine speed during driving of the air conditioning system.

It is another object of the present invention to provide a method for controlling a vehicle air conditioner capable of providing a more stable driving environment by minimizing an engine rotational speed flow phenomenon caused by driving an air conditioner.

According to an aspect of the present invention, there is provided a vehicle air conditioning control system using a vehicle air conditioner, the vehicle air conditioning system comprising: (A) comparing a coolant temperature of the engine with a set temperature; (B) variable-outputting the ECV duty when the cooling water temperature is higher than the set temperature; (C) Forcibly outputting the ECV duty constant to the set duty if the cooling water temperature is lower than the set temperature. Accordingly, engine revolutions flow due to variation of the ECV duty is prevented at the beginning of driving the vehicle, that is, when the cooling water temperature does not reach the set temperature.

At this time, the set temperature of step (A) may be set differently according to the outside temperature of the vehicle.

Meanwhile, the set duty in the step (C) may be set differently according to the vehicle outside temperature and the vehicle inside temperature.

As described above in detail, according to the method for controlling a vehicle air conditioner according to the present invention, the following effects can be expected.

That is, it is possible to provide a more stable driving environment to the driver by minimizing the change in the number of revolutions of the engine due to the operation of the air conditioner, and the reliability of the driver's vehicle performance is increased.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for controlling a vehicle air conditioner according to the present invention will be described in detail with reference to the accompanying drawings.

The reference numerals used in the components of the air conditioner to be described below are the same as those shown in Fig. 1 referred to in the background art.

FIG. 4 is a flowchart illustrating a method of controlling a vehicle air conditioner according to a specific embodiment of the present invention. FIG. 5 is a flowchart illustrating a method of controlling a vehicle air conditioner according to a specific embodiment of the present invention. The number of revolutions, the engine coolant temperature, and the ECV duty.

As shown in FIG. 4, in a method of controlling a vehicle air conditioner according to a specific embodiment of the present invention, when the vehicle is driven, whether the air conditioner is on or off is determined (S100). Here, it is assumed that the air conditioner is set to perform the cooling function of the indoor temperature of the vehicle.

If the air conditioner is turned on in step S100, the control unit 20 first receives the cooling water temperature information of the engine 10 from the cooling water temperature sensor, and determines whether the cooling water temperature is equal to or higher than the set temperature (S200).

At this time, the set temperature is preliminarily selected as an appropriate value by measuring the change of the cooling water temperature according to the driving of the engine, wherein the set temperature gradually increases with driving of the engine in a state where the cooling water temperature is reduced to a value close to the outside temperature at the beginning of driving the vehicle When the temperature of the cooling water is stabilized, the temperature of the cooling water is set so as to increase to a certain temperature or more and enter a stabilized state.

In particular, the set temperature may be set to a value that changes in accordance with the vehicle outside temperature. That is, the set temperature may be set to one value irrespective of the outside air temperature, or the outside temperature may be divided into several temperature ranges and set to a plurality of values corresponding to the respective temperature ranges. For example, if the outside temperature is below 0 ° C, the preset temperature is 77 ° C. If the outside temperature is above 0 ° C, the preset temperature can be preset to 79 ° C.

The reason why the set temperature is changed according to the outside air temperature in this way is that the temperature at which the cooling water is stabilized is somewhat influenced by the outside air temperature.

Alternatively, the set temperature may be set to a value obtained by subtracting a preset threshold value from the cooling water target temperature according to the outside air temperature. For example, if the summer coolant target temperature is 84 ° C, the winter coolant target temperature is 82 ° C, and the threshold value is set to 5 ° C, if the vehicle outside temperature corresponds to the summer temperature, Is 79 ° C minus the threshold for summer cooling water target temperature, and if the outside temperature of the vehicle corresponds to the winter temperature, the set temperature can be calculated at 77 ° C minus the threshold at the winter cooling water target temperature.

Also, the operation 200 (S200) may be performed by comparing the cooling water temperature with the set temperature, and may be performed by comparing the engine speed and the set speed. That is, when the number of revolutions of the engine decreases below the set number of revolutions, it can be determined that the cooling water temperature and the number of revolutions of the engine have entered the stabilization phase.

In this case, the set rotation speed may be set to a variable value according to the outside temperature or other factors as in the case of setting the preset temperature.

However, it is more preferable to compare the cooling water temperature and the set temperature because the engine speed is larger than the cooling water temperature, there are many other factors that change the engine speed, and it is possible to increase or decrease according to the vehicle speed control.

On the other hand, if it is determined in step 200 that the cooling water temperature is higher than the set temperature as a result of comparing the cooling water temperature with the set temperature, the controller 20 may control the compressor 20 according to a proportional integral control Adjust the ECV duty. That is, the controller 20 feedback-controls the refrigerant discharge capacity of the compressor 11 by referring to the values received from the various sensors connected to the controller 20, so that the ECV duty can be variably controlled.

In order to calculate the target ECV duty, first, the current evaporator temperature measured by the evaporator temperature sensor, the current ECV duty and the target evaporator temperature are set to be variable And calculates the target ECV duty.

Here, the target evaporator temperature is determined corresponding to the target indoor temperature set by the driver. It is also possible to consider additional variables of the outside and inside of the vehicle at this time.

Then, the calculated target ECV duty is outputted to control the compressor. Then, the process of calculating the target ECV duty is repeated by measuring the evaporator temperature again after the ECV control.

When the ECV duty is controlled by the proportional-plus-integral control method as described above, the target ECV duty is calculated by various variables, so that the output ECV duty continuously changes.

However, if it is determined in step 200 that the cooling water temperature is lower than the set temperature, the controller 20 fixes the ECV duty to a set value and outputs the fixed value (S400). That is, the ECV duty is not variablely controlled as in the ordinary case, but is constantly output as a selected one value.

That is, when the compressor torque changes as the ECV duty varies, the engine rotational speed flow corresponding to the variation of the ECV duty is detected before the cooling water temperature is stabilized, that is, before the engine rotational speed is stabilized. The ECV duty is not variably controlled but fixed at a set value.

As shown in FIG. 5, the ECV duty is fixedly set to a predetermined set duty before the cooling water temperature is stabilized after the air conditioning apparatus is turned on, that is, before the preset temperature is reached, and when the cooling water temperature is set The ECV duty is variably controlled in a general manner.

Thereby preventing the engine rotational speed from flowing due to the variation of the ECV duty at the beginning of driving the vehicle.

At this time, the set duty that is forcibly output from the controller 20 may be output as a predetermined value, a value calculated according to a predetermined formula, or a predetermined number of values.

That is, the ECV setting duty forcibly outputted until the cooling water temperature reaches the set temperature may be one value, but it may be output according to the environment inside and outside the vehicle.

In particular, the set duty can be calculated by the following equation.

Setting duty = Max ECV duty * Outside temperature factor * Outside temperature factor

Here, the ECV duty can be adjusted theoretically within the range of 0% to 100%, but it is general that the lower limit and the upper limit thereof are predetermined and adjusted only within the range. For example, the ECV duty can be adjusted within the range of 35% to 80%. Therefore, the maximum ECV duty of Equation (1) can be a value corresponding to the upper limit of the range in which the ECV duty is controlled.

However, the maximum ECV duty may not necessarily be set to a value corresponding to the upper limit value of the ECV duty control range, but may be set to another fixed value appropriately selected.

In Equation (1), the outside air temperature element and the inside air temperature element are variables within a range between 0 and 1 preset in accordance with the outside temperature and inside air temperature measured by the outside temperature sensor and the inside temperature sensor, respectively.

The outside air temperature element and the inside air temperature element are preset to higher values as the outside air temperature and the inside air temperature are higher, respectively. This is because, as the outside temperature and the inside temperature of the vehicle become higher, the required cooling amount becomes larger and the compressor driving rate must be increased.

Therefore, the outside air temperature element and the inside air temperature element can be set, for example, as shown in the following table.

Outside temperature Outside temperature element Temporary temperature Emission temperature factor Below 0 ° C 0.7 Below 0 ° C 0 0 ° C to 10 ° C 0.8 0 ° C to 10 ° C 0.1 10 ° C to 20 ° C 0.85 10 ° C to 20 ° C 0.5 20 ° C to 30 ° C 0.9 20 ° C to 30 ° C 0.75 30 ° C or higher 0.95 30 ° C or higher 0.95

As can be seen from Table 1 above, the outside temperature element and the inside temperature element can be set to rise as the outside temperature and the inside temperature rise, respectively. In addition, since it is necessary to adjust the ECV duty according to the ECV duty, the amount of cooling required inside the vehicle is more influenced by the inside temperature than the outside air temperature. Therefore, It is possible to set the temperature element to change more sensitively.

The specific values of the outside air temperature and the inside air temperature, the outside air temperature element and the inside air temperature element shown in Table 1 are only examples, and the characteristics of the vehicle, the relationship between the outside environment and the inside environment, It is possible to determine the optimal value by conducting several experiments in consideration of the temperature change and the required cooling amount.

Also, the ranges of the outside temperature and the inside temperature can be further subdivided, so that the outside temperature element and the inside temperature element can be selected from more values.

As described above, the set duty can be calculated by multiplying the fixed maximum ECV duty by a value that varies depending on the outside temperature and the inside temperature.

However, the set duty can not necessarily be calculated by Equation (1) above, but may be calculated by another predetermined formula so that the set duty can be selected to be a higher value as the outside temperature and the inside temperature become higher.

For example, in Equation (1), the set duty can be calculated by multiplying the maximum ECV duty only by the internal temperature element.

Also, the set duty may be stored in a tabular form so as to have different values depending on the temperature range, such as the inside air temperature element and the outside air temperature element.

When the set duty is calculated as described above, the controller 20 outputs a constant ECV duty until the coolant temperature reaches a set temperature, with the calculated value being a fixed value. That is, since the ECV duty is forcibly controlled until the cooling water temperature reaches the set temperature, the set duty is a value varying according to the outside air temperature and the inside air temperature, but only the outside air temperature and the inside air temperature at the time of calculating the set duty , Then the changing outside and outside temperatures are not considered until the cooling water temperature reaches the set temperature.

Steps 100 through 400 as described above may be repeatedly performed until the vehicle air conditioning apparatus is turned off. Or may not be performed repeatedly after the cooling water temperature is performed until the cooling water temperature becomes equal to or higher than the set temperature at the beginning of driving the vehicle.

It is to be understood that the invention is not limited to the disclosed embodiment, but is capable of many modifications and variations within the scope of the appended claims. It is self-evident.

For example, unlike the method of comparing the cooling water temperature with the set temperature in step 200 of FIG. 4 as described above, the engine speed can be compared with the target speed and the target speed can be set in advance.

This is because the relationship between the increase of the cooling water temperature and the convergence and the decrease of the engine speed and the convergence correspond to each other. Thus, the variables or elements related to each other in the present invention can be used as a variable or an element to replace each other.

In another embodiment, when calculating the set duty, variables other than the outside air temperature and the inside air temperature may be further considered. For example, the target temperature set by the driver in the air conditioner may be considered as another variable.

When the driver sets the cooling performance of the air conditioner to the maximum, the controller 20 selects a high value with the set duty, and when the driver sets the cooling performance of the air conditioner to the minimum, As shown in FIG.

Further, the difference between the target temperature set by the driver and the inside temperature of the vehicle in the air conditioner may be considered as another variable.

In such a case, the larger the difference between the two temperatures, the higher the set duty is calculated, and the lower the difference between the two temperatures, the lower the set duty can be calculated.

1 is a block diagram schematically showing a configuration of a general automotive air conditioner.

FIG. 2 is a graph showing changes in the engine rotation speed, the engine coolant temperature, and the ECV duty at the initial stage of driving the vehicle in an ideal air conditioning environment.

3 is a graph showing changes in the engine rotation speed, the engine cooling water temperature, and the ECV duty in the vehicle driving air-conditioning apparatus according to the prior art.

4 is a flow chart showing a step-by-step method of controlling a vehicle air conditioning system according to a specific embodiment of the present invention.

FIG. 5 is a graph showing changes in the engine rotation speed, the engine coolant temperature, and the ECV duty at the initial stage of driving the vehicle when the control method of the vehicle air conditioner according to the specific embodiment of the present invention is used.

DESCRIPTION OF REFERENCE NUMERALS

10: engine 11: compressor

12: condenser 13: electronic expansion valve

14: evaporator 20:

21: temperature sensor 22: clutch

Claims (3)

In controlling the compressor included in the air conditioner by controlling the ECV duty in the vehicle cooling control using the air conditioner for a vehicle, (A) comparing a coolant temperature of the engine with a set temperature; (B) calculating the ECV duty according to the current evaporator temperature and performing a feedback control if the cooling water temperature is equal to or higher than the set temperature; (C) Forcibly outputting the ECV duty constantly with a predetermined duty if the cooling water temperature is lower than the set temperature. The method according to claim 1, The set temperature in the step (A) And the air conditioner temperature is set differently according to the outside temperature of the vehicle. The method according to claim 1, The setting duty of the step (C) Wherein the air conditioner temperature is set differently according to the outside temperature of the vehicle and the inside temperature of the vehicle.

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