KR101152037B1 - Method for controlling electric compressor of air conditioner for vehicle - Google Patents

Abstract

The present invention relates to a method for controlling an electric compressor of a vehicle air conditioner. The present invention provides a cooling control of a vehicle air conditioner having an electric compressor (11) driven by a power source charged in a battery, the method comprising the steps of: (A) detecting the current vehicle speed and the engine speed, (B) sensing Calculating the limit rotation speed of the motor-compressor 11 corresponding to the vehicle speed and the engine speed, and (C) adjusting the rotation speed of the motor-compressor 11 below the calculated limit rotation speed; Is performed. According to the present invention as described above, the power consumption of the motor-driven compressor 11 in the idle state of the vehicle is reduced, thereby improving driving performance and fuel economy of the vehicle.

Hybrid vehicles, electric compressors, engine speed, air conditioning

Description

TECHNICAL FOR CONTROLLING ELECTRIC COMPRESSOR OF AIR CONDITIONER FOR VEHICLE}

The present invention relates to a method of controlling an electric compressor of a vehicle air conditioner, and more particularly, to a method of controlling an electric compressor of a vehicle air conditioner which reduces the driving ratio of the motor compressor of a vehicle air conditioner when a vehicle speed and an engine speed are low in a hybrid vehicle. It is about.

In a general vehicle air conditioner having a mechanical compressor operated by receiving a driving force from an engine, the compressor performance of the air conditioner varies according to the engine speed or the vehicle speed. That is, when the engine speed is high, the compressor performance of the air conditioner is high, but when the engine speed is low, the compressor performance of the air conditioner is also relatively low. However, this difference can be compensated by adjusting the opening degree of the temperature control door, and does not significantly affect the overall cooling performance of the air conditioner.

The engine rotation speed is low, so the driving force transmitted to the compressor of the air conditioner decreases, so that the refrigerant discharge capacity of the compressor decreases. However, the opening angle of the temperature control door is larger than that of the cold air discharged from the cold passage. This is because it is possible to adjust the mixing so that ultimately the cooling performance of the air conditioner is not affected.

On the other hand, in a hybrid vehicle, an engine and an electric motor are simultaneously used as driving sources of the vehicle. That is, when starting or when a large driving force is required, the engine is used as a driving source of the vehicle, and when a large driving force is not required such as when driving on a flat surface or when stopping, an electric motor is used as a driving source. Since such hybrid vehicles are operated with fossil fuels, reducing the operating time of engines that cause environmental pollution, related technologies continue to be developed.

In such a hybrid vehicle, an electric compressor is used. Electric compressor has no big difference in configuration or operation principle with general compressor, but discharges refrigerant by receiving rotational power of electric motor driven by using power charged in battery as driving power.

In this case, since the electric compressor is driven by using a power charged in the battery, the electric compressor may exhibit a constant performance regardless of the vehicle speed or the engine speed. Therefore, in the case of an air conditioner having an electric compressor, unlike the air conditioner having a mechanical compressor, the electric compressor is controlled at the same output as in the high-speed driving state even in a vehicle idle state with low vehicle speed and engine speed.

However, when the electric compressor is controlled in this way, more power may be consumed in the air conditioning apparatus than in the case of cooling the inside of the vehicle by using the mechanical compressor. In the case of a mechanical compressor, the power consumed for driving the compressor is less than the driving state in the vehicle idle state, whereas in the case of an electric compressor, the power consumed for driving the compressor is the same as the driving state in the vehicle idle state.

Therefore, when the electric compressor is used, the power consumption is greater than when the mechanical compressor is used. As a result, the vehicle load increases and the discharge speed of the battery power increases, which may adversely affect the power supply required for driving the vehicle. .

In addition, the amount of power consumed by the air conditioner has a problem in that the consumption of battery power is fast, and accordingly, the engine driving or battery charging is required to charge the battery, thereby preventing the fuel economy of the vehicle from being improved.

In addition, the engine needs to be driven more or powered from the outside to charge the battery. In this case, fossil fuels are ultimately used to promote environmental pollution.

Therefore, the present invention has been made to solve the above-mentioned conventional problems, an object of the present invention is to limit the number of revolutions of the electric compressor in the state of low vehicle speed and engine speed of the hybrid vehicle to reduce the power consumption in the air conditioning apparatus It is to provide a method of controlling an electric compressor of a vehicle air conditioner.

Another object of the present invention is to provide a method of controlling an electric compressor of an air conditioner for a vehicle, which helps to improve driving performance and vehicle fuel efficiency by reducing power consumed by the electric compressor of a hybrid vehicle.

Still another object of the present invention is to provide a method of controlling an electric compressor of an air conditioner for a vehicle, which may help environmental protection by reducing power consumed in the electric compressor of a hybrid vehicle.

According to a feature of the present invention for achieving the object as described above, the present invention provides a cooling control of the air conditioner for a vehicle having an electric compressor driven by the power source charged in the battery as (A) the current vehicle speed and Detecting an engine speed; (B) calculating a limit speed of the electric compressor corresponding to the detected vehicle speed and engine speed; (C) adjusting the rotational speed of the electric compressor below the calculated limit rotational speed.

In the electric compressor control method, as a result of determining based on the current vehicle speed and engine speed information detected in the step (A), the steps (B) and (C) only when the vehicle corresponds to an idle state. ) Steps may be performed sequentially.

Wherein the limit rotation speed is determined to be a larger value of a first limit rotation speed preset in correspondence with a current vehicle speed and a second limit rotation speed preset in correspondence with a current engine speed: wherein the first limit rotation speed is: The vehicle speed is correspondingly increased as the vehicle speed increases, but is set to converge to the maximum rotational speed of the electric compressor; The second limit rotation speed may be set to increase correspondingly as the engine speed increases, but converge to the maximum rotation speed of the electric compressor.

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

That is, the power consumption of the air conditioner can be reduced by limiting the rotation speed of the electric compressor in a state where the vehicle speed and the engine speed of the hybrid vehicle are low.

In addition, the electric compressor control method of the vehicle air conditioner according to the present invention has the advantage that it is possible to improve the driving performance and vehicle fuel economy by reducing the power consumed in the electric compressor of the hybrid vehicle.

In addition, according to the method of controlling the electric compressor of the vehicle air conditioner according to the present invention, there is an advantage in that it helps to protect the environment by reducing the power consumed in the electric compressor of the hybrid vehicle.

Hereinafter, with reference to the accompanying drawings a specific embodiment of the electric compressor control method of the vehicle air conditioner according to the present invention as described above will be described in detail.

1 is a block diagram schematically showing the configuration of an air conditioning apparatus and a motor-driven compressor driving source of a general hybrid vehicle, and FIG. 2 is a flowchart illustrating a step-by-step method of controlling an electric compressor of a vehicle air conditioner according to a specific embodiment of the present invention. 3A is a graph illustrating a relationship between a limiting speed of a motor-driven compressor and a vehicle speed in a method of controlling an electric compressor of a vehicle air conditioner according to a specific embodiment of the present invention, and FIG. 3B is a graph of the present invention. It is a graph showing the relationship between the limit rotational speed and the engine rotational speed for the electric compressor in the electric compressor control method of the vehicle air conditioner.

The air conditioner of a general hybrid vehicle is generally configured as shown in FIG. 1.

That is, the electric compressor 11 compresses the refrigerant and changes the rotation speed according to the cooling demand, the condenser 12 condensing the refrigerant discharged from the electric compressor 11, and liquefies through the condenser 12. By adiabatic expansion of the refrigerant to make the gas and liquid mixed, the ambient expansion by using the electromagnetic expansion valve 13 whose opening degree changes according to the refrigerant discharge amount of the electric compressor 11 and the latent heat of evaporation when the refrigerant is vaporized After cooling the air, the evaporator 14 for returning the refrigerant to the electric compressor 11 and the air-conditioning environment such as indoor and outdoor temperatures input from various sensors installed inside and outside the vehicle are inputted by the user. It is composed of a control unit 20 for controlling the rotational speed of the electric compressor (11) in accordance with the air conditioning conditions.

In this case, the controller 20 controls the rotational speed of the motor-compressor 11. First, the controller 20 is first measured by an evaporator temperature sensor in order to calculate a target rotational speed of the motor-compressor 11. The target rotation speed is calculated using the current evaporator temperature, the current rotation speed and the target evaporator temperature as variables.

Here, the target evaporator temperature is determined corresponding to the target indoor temperature set by the driver. In addition, other variables in the exterior and interior of the vehicle may be additionally considered.

Then, the electric compressor 11 is controlled at the calculated target rotational speed. Then, the process of calculating the target rotation speed by measuring the evaporator temperature is repeated.

In particular, in a specific embodiment of the present invention, the control unit 20 calculates the limit rotation speed under a predetermined condition, and when the target rotation speed is smaller than the limit rotation speed, the rotation speed of the electric compressor 11 is the target rotation speed. When the target rotational speed is greater than the limited rotational speed, the rotational speed of the electric compressor 11 may be adjusted to the limited rotational speed. This will be described in more detail later with reference to FIG. 2.

At this time, the power provided to the electric compressor 11, first, the rotational force by the engine 10 and the wheel drive motor (not shown) and the like is converted into electrical energy in the generator 31, the generator 31 The converted electrical energy is generated by storing chemical energy in the battery 32.

In addition, the inverter 33 receives the DC power from the battery 32 and converts the AC power into a frequency variable.

In addition, the energy stored in the battery 32 is transferred to the electric motor 34 via the inverter 33 is converted into physical energy, which is in turn transferred to the electric compressor 11 to drive the electric compressor 11. Let's do it.

That is, the driving force of the electric compressor 11 is supplied from the battery 32 through the inverter 33 and the electric motor 34.

When operating the air conditioning device configured as described above, the control unit 20 is an air conditioning condition, such as indoor temperature and outdoor temperature transmitted from various sensors, and the air conditioning conditions, such as selecting the vehicle indoor set temperature, heating or cooling set by the user As a result, the rotation speed of the compressor 11 is changed.

The refrigerant discharged from the electric compressor 11 is condensed and liquefied while passing through the condenser 12, and gas and liquid are mixed while passing through the expansion valve 13. In this case, the opening degree of the expansion valve 13 is changed according to the amount of refrigerant discharged from the electric compressor 11.

Thereafter, the refrigerant introduced into the evaporator 14 is vaporized to cool the surrounding air through heat exchange with the surrounding air. That is, since the latent heat of evaporation required to evaporate the refrigerant from the ambient air, the temperature of the ambient air of the evaporator 14 is lowered.

The vaporized refrigerant is introduced into the electric compressor 11 again, and the air cooled through heat exchange is supplied to the room to cool the room. At this time, the temperature sensor 21 for detecting the temperature of the air is installed on the outlet side of the evaporator 14, if the temperature of the evaporator outlet side is a predetermined temperature or less the control unit 20 from the battery 32 to the inverter By stopping the rotation of the electric motor 34 through the 33 to stop the operation of the electric compressor (11).

This is to prevent the water vapor contained in the air frozen in the condensed state in the evaporator 14 to inhibit the heat exchange.

As such, when the electric motor 34 is turned off, power transmission to the electric compressor 11 is interrupted, and the rotation of the electric compressor 11 is stopped. Accordingly, when the temperature of the evaporator outlet falls below a specific temperature for stopping the operation of the electric compressor 11, the electric motor 34 is turned off to stop the operation of the electric compressor 11 and the circulation of the refrigerant is stopped. Is stopped.

Since the heat exchange between the evaporator 14 and the ambient air does not occur when the circulation of the refrigerant is stopped, the evaporator outlet temperature gradually increases, and when the evaporator outlet temperature rises above the threshold temperature, the inverter 33 again returns the electric motor ( 34. The electric compressor 11 is operated by resuming power supply. Of course, since the temperature of the evaporator outlet is lowered when the compressor 11 is operated again, the above process may be repeated.

The method of controlling the electric compressor of the vehicle air conditioner having the above configuration starts with checking whether the air conditioner is on or off as shown in FIG. 2 (S100). In this case, the on / off of the air conditioner means the on / off of the vehicle cooling function of the air conditioner.

If the air conditioner is turned on in step 100 (S100), the control unit 20 receives the current vehicle speed and engine speed (RPM) information of the vehicle (S200). At this time, the control unit 20 is connected to the vehicle speed sensor and the engine speed sensor to receive the vehicle speed and engine speed information of the vehicle, respectively.

When the controller 20 receives the vehicle speed and the engine speed information in operation 200, the controller 20 determines whether the vehicle is in the idle state by using the vehicle speed and the engine speed information. (S300).

At this time, the vehicle is in the idle state, which means that the vehicle is low speed and the load on the engine is small. When the vehicle speed is less than or equal to the preset speed and the engine speed is less than or equal to the preset speed, the vehicle is in the idle state. You can judge. At this time, each of the set speed and the rotation speed is preselected to an appropriate number capable of determining the state of the vehicle.

If it is determined in step 300 (S300) that the vehicle is in the idle state, the setting of the air conditioning apparatus currently operated by the driver is confirmed (S400). In other words, it is determined whether or not the cooling performance of the air conditioning apparatus is operated to the maximum.

If it is determined in step 400 that the driver has set the cooling performance of the air conditioning apparatus to the maximum, the control unit 20 controls the motor compressor 11, the number of rotations of the motor compressor 11 To control within the range of rotation speed preset in the control unit 20 (S500).

That is, when the rotational speed range set in advance in the control unit 20 to control the electric compressor 11 is a range within the minimum rotational speed and the maximum rotational speed, the control unit 20 controls the electric compressor 11. Within the range, adjust the current vehicle internal temperature, evaporator temperature, target internal temperature, target evaporator temperature, etc. That is, the rotation speed of the electric compressor 11 is adjusted by a general feedback control method.

On the other hand, if it is determined that the driver does not set the air conditioner's cooling performance to the maximum in step 400, the controller 20 limits the rotation according to the vehicle speed information and the engine speed information received in step 200. The number is calculated (S600).

Here, the limited rotational speed is one value within the range of the electric compressor rotational speed set in the control unit 20, and is calculated to be larger than the minimum rotational speed and less than or equal to the maximum rotational speed.

In this case, the limit rotation speed is a value set to limit the maximum value of the rotation speed of the electric compressor 11 to a value less than the maximum rotation speed in the idle state of the vehicle in order to reduce the power consumed in the air conditioning apparatus. The value is selected according to the current vehicle speed and the engine speed in the vehicle idling state.

In order to calculate the limit rotation speed in the 600th step S600, a function indicating a relationship between the vehicle speed and the limit rotation speed as shown in FIGS. 3A and 3B and a relationship between the engine speed and the limit rotation speed are shown. The function may be stored in advance.

As shown in Fig. 3A, first, the relationship between the vehicle speed and the limit rotational speed of the electric compressor 11 has a value that the limit rotational speed is smaller as the vehicle speed is slower, and the limit rotational speed is higher as the vehicle speed is increased. When the vehicle speed increases to a value outside the idle state of the vehicle, the limit rotational speed becomes equal to the maximum rotational speed so that the rotational speed of the electric compressor 11 is no longer limited.

In the drawing, when the speed of the vehicle increases from zero, the initial limit rotational speed is shown to be set equal to the minimum rotational speed, but it is not necessarily so and may be set to increase gradually from a value greater than the minimum rotational speed.

In addition, as shown in FIG. 3B, the relationship between the engine speed and the limit speed of the motor-driven compressor 11 also has a smaller value as the vehicle speed is slower, and the limit speed is increased as the vehicle speed increases. Can be expressed as a function.

When the engine speed increases to a value outside the idle state of the vehicle, the limited rotation speed becomes equal to the maximum rotation speed so that the rotation speed of the electric compressor 11 is no longer limited.

In FIG. 3B, when the rotational speed of the vehicle engine increases from 0, the first motor-driven compressor 11 limiting rotational speed is shown to be set equal to the minimum rotational speed, but this is only an example and the initial value of the limiting rotational speed is the minimum. It may be set to increase gradually at a value greater than the number of revolutions.

Also, the waveform of the function shown in FIGS. 3A and 3B is not limited to increasing linearly as shown.

In addition, the relationship between the vehicle speed and the limit rotational speed, and the relationship between the engine speed and the limiting rotational speed may be preset as a continuous function as described above, but predetermine a plurality of vehicle speed ranges or engine speed ranges, The limit rotation speed corresponding to each range may be predetermined and stored in advance as a table in the controller 20.

In addition, the controller 20 may control the rotation speed of the electric compressor 11 by selecting a higher value as the limit rotation speed among the limit speeds set corresponding to the current vehicle speed and the engine speed of the vehicle.

That is, the control unit 20 calculates the limit rotation speed to one value, and adjusts the rotation speed of the electric compressor 11 between the minimum rotation speed and the limit rotation speed.

In this case, the limited rotation speed in operation 600 may be calculated by the following equation.

Speed limit = MAX (speed limit corresponding to the current vehicle speed, speed limit corresponding to the current engine speed)

As described above, the controller 20 receives the current vehicle speed and the engine speed in operation 200 as described above, and limits the rotations corresponding to the current vehicle speed and the engine speed from the pre-stored function or table, respectively. Read the number. Then, the two read values are compared to set a larger value as the limit speed of the electric compressor 11.

When the limit rotation speed is selected as described above, the controller 20 adjusts the rotation speed of the electric compressor 11 so that the rotation speed of the electric compressor 11 does not exceed the limit rotation speed (S700).

That is, the rotation speed of the electric compressor 11 is controlled to a value determined in consideration of the vehicle internal temperature, the evaporator temperature, the target temperature and the target evaporator temperature, etc., between the minimum rotation speed and the current limit rotation speed.

However, the method for calculating the limited rotational speed in step 600 is not limited to the method described above. That is, unlike the above description, only one of the function indicating the relationship between the vehicle speed and the limit rotational speed or the function indicating the relationship between the engine speed and the limiting rotational speed may be used as a function for determining the limiting rotational speed.

And such a series of processes are repeatedly performed until the air conditioner is turned off (S800).

In this case, when the control unit 20 determines that the state of the vehicle is an idle state in step 300, and controls not to increase the rotation speed of the motor-compressor 11 above the limit rotation speed, The opening angle of the temperature control door can be adjusted so that there is no effect.

At this time, the temperature control door is to adjust the opening degree of the cold air passage and the warm air passage of the air conditioning apparatus, in order to increase the cooling performance of the vehicle, the angle of the temperature control door in the direction of increasing the opening degree of the cold air passage and reducing the opening degree of the warm air passage. It must be adjusted.

The rights of the present invention are not limited to the embodiments described above, but are defined by the claims, and various changes and modifications can be made by those skilled in the art within the scope of the claims. It is self-evident.

For example, without determining whether the vehicle is in an idle state in step 300, the vehicle speed or the engine speed in the relationship between the vehicle speed and the limit speed, the engine speed and the limit speed is more than the set range, the limit The electric compressor 11 may be controlled by using a speed convergence to the maximum speed.

In addition, in step 400, it is not necessary to determine whether the air conditioner is set to the maximum cooling mode. For example, the difference between the current temperature inside the vehicle and the set temperature set by the driver is greater than or equal to a preset threshold. If the evaporator temperature and the target evaporator temperature are preset values, the evaporator temperature may be increased up to the maximum rotation speed without limiting the rotation speed of the electric compressor 11.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram schematically showing the configuration of an air conditioning apparatus and a motor-driven compressor driving source of a typical hybrid vehicle.

Figure 2 is a flow chart illustrating a step-by-step method of controlling the electric compressor of the air conditioner for vehicles according to a specific embodiment of the present invention.

Figure 3a is a graph showing the relationship between the speed limit and the vehicle speed for the electric compressor in the electric compressor control method of the vehicle air conditioner according to a specific embodiment of the present invention.

Figure 3b is a graph showing the relationship between the rotational speed and the engine speed for the electric compressor in the electric compressor control method of the vehicle air conditioner according to a specific embodiment of the present invention.

** Description of the symbols for the main parts of the drawings **

10: engine 11: electric compressor

12: condenser 13: expansion valve

14: evaporator 20: control unit

31: generator 32: battery

33: Inverter 34: Electric Motor

Claims (4)

In the cooling control of a vehicle air conditioner having an electric compressor driven by a power source charged in a battery, (A) detecting a current vehicle speed and engine speed; (B) calculating a limit speed of the electric compressor corresponding to the detected vehicle speed and engine speed; (C) adjusting the rotational speed of the electric compressor below the calculated limit rotational speed, Steps (B) and (C) are sequentially performed only when the vehicle is in an idle state as a result of the determination based on the current vehicle speed and engine speed information detected in step (A). Electric compressor control method of a vehicle air conditioner. delete The method of claim 1, The limit rotation speed is, The control method of the electric compressor characterized in that it is determined to be a larger value of the first limited speed preset in correspondence with the current vehicle speed and the second limited speed preset in accordance with the current engine speed. The method of claim 3, wherein The first limit rotational speed is, The vehicle speed is correspondingly increased as the vehicle speed increases, but is set to converge to the maximum rotational speed of the electric compressor; The second limit rotational speed is, The engine compressor control method characterized in that the increase in the number corresponding to the increase in the engine speed is set to converge to the maximum speed of the electric compressor.

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