JP2002248934A - Vehicular air conditioner and its operating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reasonable air-conditioning technique capable of properly adjusting the air intake negative pressure of a vehicular engine air intake system when the engine revolution is low in the vehicular air conditioner equipped with an air-conditioning circuit and a motor compressor for circulating refrigerant to the air-conditioning circuit. SOLUTION: The vehicular air conditioner 1 is provided with a pressure sensor 32 for detecting the air suction pressure Pa in the suction system 30 of the engine E. For example, during idling when the engine revolution is low and the suction pressure Pa detected by the pressure sensor 32 is higher than a setting pressure Pb (negative pressure is insufficient), the number of revolution of the motor compressor C is lowered than a normal mode, the output of the engine E is lowered, and then the throttle valve 4D is throttled up to a setting value, so that the air intake negative pressure of the air intake system 30 can be controlled to the value ensuring the assisting force of the foot brake F.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for a vehicle, and more particularly, to an air conditioning technology for an air conditioner for a vehicle having an air conditioning circuit and an electric compressor for circulating a refrigerant through the air conditioning circuit.

[0002]

2. Description of the Related Art Generally, an air conditioner for a vehicle or the like is equipped with a compressor for circulating a refrigerant through an air conditioning circuit. The compressor is configured to perform a compression operation of a refrigerant that compresses a sucked refrigerant to increase the pressure and discharge the refrigerant. by the way,
In this type of vehicle, the intake pressure of the vehicle engine, specifically, the intake pressure downstream of the throttle valve is used for the assist force of the foot brake. And
As the degree of negative pressure of the intake pressure increases (the intake pressure decreases), the assisting force of the foot brake increases. Therefore, it is necessary to set this intake pressure to a negative pressure that can secure the assisting force of the foot brake. However, when the compressor is operated during idling, for example,
The output of the vehicle engine increases, the engine speed decreases, and the degree of negative pressure of the intake pressure of the vehicle engine decreases (the intake pressure increases), making it difficult to secure the assisting force of the foot brake. Conventionally, when idling at a low engine speed, the compressor is stopped and the output of the vehicle engine is reduced, and then the intake air is throttled to avoid a reduction in the negative pressure of the intake pressure of the vehicle engine. Is controlled. As a result, the intake pressure of the vehicle engine can be set to a negative intake pressure that can ensure the assist force of the foot brake.

[0003]

However, in the above-described conventional air conditioner for a vehicle, there is a problem that the air conditioner cannot be operated during this time because the operation of the compressor is stopped at the time of idling. The present invention has been made in view of the above points, and an object of the present invention is to provide a vehicle air conditioner including an air conditioning circuit and an electric compressor that circulates a refrigerant through the air conditioning circuit. It is an object of the present invention to provide a rational air-conditioning technology capable of suitably adjusting the intake negative pressure of an intake system of a vehicle engine when the engine speed is low.

[0004]

In order to solve the above-mentioned problems, an air conditioner for a vehicle according to the present invention is configured as described in claims 1 to 3. The method of operating the vehicle air conditioner of the present invention is as described in claims 4 to 6. The invention according to claims 1 to 6 is a vehicle air conditioner in which a refrigerant is circulated to an air conditioning circuit by an electric compressor. By controlling the electric compressor and the like, the intake negative pressure of the intake system of the vehicle engine is preferably adjusted. It is a technology that adjusts to

[0005] In the vehicle air conditioner according to the first aspect, an electric compressor is provided in the air conditioning circuit. This electric compressor compresses refrigerant in an air conditioning circuit to increase the pressure and discharges the refrigerant. For example, a scroll compressor or the like is suitably used in a vehicle. The electric compressor is driven in at least two modes: a negative pressure securing mode and a steady mode. In the negative pressure securing mode, the electric compressor is set to a lower rotational speed than in the steady mode based on the intake negative pressure of the intake system of the vehicle engine.
Then, by performing the negative pressure securing mode, the intake negative pressure of the intake system is controlled to a predetermined desired value. In addition,
The term “intake negative pressure” as used herein indicates a negative pressure of the intake pressure, and means that as the intake negative pressure decreases, the degree of negative pressure increases (changes from the atmospheric pressure to the negative pressure side). This means that as the negative pressure increases, the degree of the negative pressure decreases (changes to approach the atmospheric pressure). Thus, for example, during idling of a vehicle engine having a low engine speed, the rotational speed of the electric compressor is reduced from a normal steady mode, the output of the vehicle engine is reduced, the intake air is throttled, and the intake air of the intake system is reduced. An increase in the negative pressure can be avoided. This intake pressure is suitably used for assisting force of the vehicle foot brake. Therefore, when the assist force of the foot brake corresponds to the intake negative pressure of the intake system, the intake negative pressure of the intake system is controlled to a value that can at least secure the assist force of the foot brake, so that the assist of the foot brake is reduced. Power can be secured. As described above, according to the vehicle air conditioner described in claim 1,
When the engine speed is low, the intake negative pressure of the intake system of the vehicle engine can be suitably adjusted, and, for example, the assisting force of the vehicle foot brake can be secured. Thus, it is possible to prevent the operation of the electric compressor from being stopped as in the related art, and to secure the intake negative pressure of the intake system.

Further, in the vehicle air conditioner according to the second aspect, control is performed to change the valve opening of the throttle valve of the vehicle engine in the negative pressure securing mode and the steady mode. That is, when switching from the steady mode to the negative pressure securing mode in order to secure the intake negative pressure of the intake system, the intake can be throttled by changing the throttle valve in the closing direction. Thereby, for example, at the time of idling when the engine speed is low, the speed of the electric compressor is decreased from the normal steady mode, the output of the vehicle engine is reduced, and then the throttle valve is changed in the closing direction. It is possible to avoid an increase in the intake negative pressure of the intake system.

Further, in the air conditioner for a vehicle according to the third aspect, the negative pressure of the intake air in the intake system includes an intake pressure of the intake system, a pressure of a negative pressure tank, a valve opening of a throttle valve of a vehicle engine, and a vehicle. It is determined by any one of the fuel injection amounts of the engine or a combination of these pieces of information. This information may be a case where data is directly detected, or a case where preset data is used. The intake negative pressure of the intake system is obtained, for example, by directly detecting the intake pressure. Also,
The negative pressure tank is provided for applying an assist force to the vehicle foot brake, and the intake negative pressure of the intake system is obtained by, for example, directly detecting the pressure of the negative pressure tank. In addition, the intake negative pressure of the intake system is obtained by detecting, for example, the valve opening of a throttle valve. Further, the intake negative pressure of the intake system is obtained by detecting the fuel injection amount. As described above, according to the vehicle air conditioner of the third aspect, the detection target for determining the intake negative pressure of the intake system can be appropriately changed as necessary.

In the method for operating a vehicle air conditioner according to a fourth aspect, the electric compressor is driven in at least two modes, ie, a negative pressure securing mode and a steady mode, so that, for example, idling at a low engine speed. At times, it is possible to suitably adjust the intake negative pressure of the intake system of the vehicle engine, and to secure, for example, the assisting force of the vehicle foot brake.
Thus, it is possible to prevent the operation of the electric compressor from being stopped as in the related art, and to secure the intake negative pressure of the intake system.

According to a fifth aspect of the present invention, in the method of operating a vehicle air conditioner, for example, during idling when the engine speed is low, the rotation speed of the electric compressor is reduced from the steady mode to reduce the output of the vehicle engine. In addition, by changing the throttle valve in the closing direction, it is possible to avoid an increase in the intake negative pressure of the intake system.

In the method for operating a vehicle air conditioner according to the present invention, the negative pressure of the intake air of the intake system, the pressure of the negative pressure tank, the valve opening of the throttle valve of the vehicle engine, Since the fuel injection amount of the vehicle engine is determined by combining the plurality of pieces of information or the plurality of pieces of information, the detection target for determining the intake negative pressure of the intake system can be appropriately changed as necessary.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration and the like of a vehicle air conditioner according to an embodiment of the present invention will be described below with reference to the drawings. Here, FIG. 1 is a configuration diagram showing a main configuration of the vehicle air conditioner of the present embodiment. The vehicle air conditioner 1 shown in FIG. 1 has an air conditioning circuit 2 as a refrigerant circulation path.
Further, an electric compressor C for compressing the refrigerant to high pressure to discharge the refrigerant, a condenser 10 as a condenser, an evaporator 12, an evaporator 12, a receiver 14, an expansion valve 20, and the like are provided. Further, an inverter I for controlling the electric motor M of the electric compressor C is provided. As the electric compressor C, for example, a scroll type is used.

An engine E (corresponding to the vehicle engine in the present invention) as a driving source of the vehicle is mechanically connected to the alternator O, and the alternator O is electrically connected to the battery B and the inverter I. Have been. That is, the electric power generated by the alternator O is supplied to the electric motor M via the inverter I and stored in the battery B. A pressure sensor 3 for detecting the intake pressure of air in the intake system 30 of the engine E, that is, the pressure downstream of the throttle valve 40.
2 are provided. The intake pressure of the intake system 30, that is, the downstream pressure of the throttle valve 40 is used as an assisting force of a foot brake (corresponding to a vehicle foot brake in the present invention), and the intake pressure decreases (negative pressure). The greater the degree, the greater the assisting force of the foot brake.

The inverter I is configured to control the electric motor M, the throttle valve 40 and the like based on various information such as detection data. In the present embodiment, as described later, the electric motor M and the throttle valve 4 are controlled based on the detection data detected by the pressure sensor 32.
A control signal is output to 0 or the like.

Next, a method of controlling the intake pressure in the intake system 30 of the engine E will be described with reference to FIGS. Here, FIG. 2 is a flowchart showing the intake negative pressure control process, FIG. 3 is a flowchart showing the electric compressor control process, and FIG. 4 is a flowchart showing the throttle valve control process.

In the present embodiment, during idling at a low engine speed, the intake pressure of the intake system 30 of the engine E is controlled to be a negative intake pressure effective for the assisting force of the foot brake F. Specifically, the intake negative pressure control process is performed according to the flowcharts shown in FIGS. This intake negative pressure control process control is performed using the inverter I. First, as shown in FIG.
When idling with a low engine speed, the pressure sensor 3
2, the intake pressure Pa of the intake system 30 is detected [Step S10]. Then, a comparison is made between the intake pressure Pa detected by the pressure sensor 32 and a predetermined set pressure Pb [Step S12]. When it is determined in this step S12 that the intake pressure Pa is larger than the set pressure Pb (the degree of negative pressure is insufficient) (YES).
Proceeds to step S20, and performs the electric compressor control process shown in FIG. On the other hand, if it is determined in step S12 that the intake pressure Pa is smaller than the set pressure Pb (the negative pressure degree is secured) (NO), it is not necessary to adjust the intake pressure Pa, and thus the intake negative pressure is not changed. The control processing ends.
The set pressure Pb is set based on an intake negative pressure effective for the assist force of the foot brake F.

In the electric compressor control process shown in FIG. 3, the number of revolutions of the electric compressor C is reduced by controlling the number of revolutions of the electric motor M by the inverter I. First, in step S22, the rotation speed Na of the electric motor M is reduced from the steady mode to the negative pressure securing mode (set value Nd).
The set value Nd is, for example, the intake pressure Pa of the intake system 30.
It is set appropriately according to the valve opening of the throttle valve 40 and the like. Next, the rotation speed Na of the electric motor M is detected (step S24), and the rotation speed Na is set to the set value Nd.
It is determined whether or not it has reached [Step S26]. The rotation speed Na of the electric motor M may be directly detected by a device that detects the rotation speed, or may be obtained indirectly from a control signal output to the electric motor M. . If it is determined in step S26 that the rotation speed Na has reached the set value Nd (YES), the electric compressor control process is terminated as it is, and step S3 in FIG.
The routine proceeds to 0, and the throttle valve control processing shown in FIG. 4 is performed. On the other hand, when it is determined in step S26 that the rotation speed Na has not reached the set value Nd (NO), the process returns to step S22, and the processes in steps S22 to S26 are sequentially continued. Thus, by controlling the rotation speed of the electric motor M, the rotation speed of the electric compressor C is reduced to a desired rotation speed. That is, in the negative pressure securing mode, the rotation speed of the electric compressor C is lower than in the steady mode. Also,
By this electric compressor control, the power generation amount of the alternator O and the output of the engine E are reduced.

In the throttle valve control process shown in FIG. 4, the valve opening Ba of the throttle valve 40 is controlled by the inverter I. First, in step S32, the throttle valve 40 is closed from the steady mode to the negative pressure securing mode (set value Bd). This set value Bd is
For example, it is appropriately set according to the intake pressure Pa of the intake system 30, the rotation speed of the electric motor M, and the like. Next, the valve opening degree Ba of the throttle valve 40 is detected [Step S
34], it is determined whether or not the valve opening Ba has reached the set value Bd [step S36]. The valve opening Ba of the throttle valve 40 may be directly detected by a device for detecting the valve opening,
It may be a case where the value is indirectly obtained from the control signal output to the throttle valve 40. When it is determined in step S36 that the valve opening Ba has reached the set value Bd (YE
S) terminates the throttle valve control processing as it is,
It returns to step S10 in FIG. On the other hand, step S36
If it is determined that the valve opening Ba has not reached the set value Bd (NO), the process returns to step S32 and the processes from steps S32 to S36 are sequentially continued. Thus, the throttle valve 40 is reduced to a desired valve opening. By the above procedure, the intake system 30
Is set to a desired intake negative pressure effective for the assisting force of the foot brake F.

As described above, according to the present embodiment, during idling at a low engine speed, the speed of the electric motor M is reduced to the set value Nd lower than the steady mode, and the output of the vehicle engine E is reduced. Further, by closing the throttle valve 40 to the set value Bd, the intake system 3
It is possible to prevent the intake pressure Pa of 0 from becoming larger than the set value Pb at which the assisting force of the foot brake can be secured. As a result, it is possible to avoid securing the intake negative pressure by stopping the operation of the electric compressor C as in the related art.

It should be noted that the present invention is not limited to only the above embodiment, and various applications and modifications are conceivable.
For example, each of the following embodiments to which the above embodiment is applied may be implemented. In the above-described embodiment, the case where the intake negative pressure of the intake system 30 of the engine E is determined by the detection data of the intake pressure of the intake system 30 has been described. May be determined based on at least one of the following information: the pressure of the negative pressure tank, the opening degree of the throttle valve 40 of the vehicle engine E, and the fuel injection amount of the vehicle engine E.

[0020]

As described above, according to the present invention,
In a vehicle air conditioner including an air conditioning circuit and an electric compressor that circulates refrigerant through the air conditioning circuit, when the engine speed is low, the intake negative pressure of the intake system of the vehicle engine can be suitably adjusted. A rational air conditioning technology can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a main configuration of a vehicle air conditioner of the present embodiment.

FIG. 2 is a flowchart illustrating intake negative pressure control processing.

FIG. 3 is a flowchart showing an electric compressor control process.

FIG. 4 is a flowchart showing a throttle valve control process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Vehicle air conditioner 2 ... Air conditioning circuit 30 ... Intake system 32 ... Pressure sensor 40 ... Throttle valve E ... Engine (vehicle engine) F ... Foot brake (vehicle foot brake) C ... Electric compressor I ... Inverter M ... Electricity motor

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuya Kimura 2-1-1, Toyota-cho, Kariya-shi, Aichi Pref. Inside Toyota Industries Corporation (72) Inventor Yoshikazu Fukuya 2-1-1, Toyota-cho, Kariya-shi, Aichi Pref. F-term in Toyota Industries Corporation (reference) 3H045 AA06 AA09 AA12 AA27 BA12 CA09 DA05 EA13 EA17

Claims (6)

[Claims] 1. An air conditioner for a vehicle, comprising: an air conditioning circuit; and an electric compressor that compresses a refrigerant to increase the pressure and discharges the refrigerant, wherein the electric compressor circulates the refrigerant through the air conditioning circuit to perform air conditioning. The electric compressor includes at least a negative pressure securing mode set to a predetermined rotational speed based on an intake negative pressure of an intake system of a vehicle engine, and a steady mode having a higher rotational speed than the negative pressure securing mode. An air conditioner for a vehicle, which is configured to be driven in two modes. 2. The vehicle air conditioner according to claim 1, wherein the negative pressure securing mode and the steady mode include a control for changing a valve opening of a throttle valve of the vehicle engine. An air conditioner for a vehicle. 3. The air conditioner for a vehicle according to claim 1, wherein the negative pressure of the intake air is an intake pressure of an intake system, a pressure of a negative pressure tank for applying an assist force to a vehicle foot brake, An air conditioner for a vehicle, wherein the air conditioner is configured to be determined by at least one of information of a valve opening of a throttle valve of a vehicle engine and a fuel injection amount of the vehicle engine. 4. A method for operating a vehicle air conditioner, comprising: an air conditioning circuit; and an electric compressor that compresses refrigerant to increase pressure and discharges the refrigerant, wherein the electric compressor circulates refrigerant through the air conditioning circuit to perform air conditioning. The electric compressor is provided with a negative pressure securing mode set to a predetermined rotational speed based on at least an intake negative pressure of an intake system of a vehicle engine, and a steady state of a higher rotational speed than the negative pressure securing mode. A method for operating a vehicle air conditioner, wherein the vehicle is driven in two modes. 5. The method for operating a vehicle air conditioner according to claim 4, wherein in the negative pressure securing mode and the steady mode, control is performed to change a valve opening of a throttle valve of the vehicle engine. A method of operating a vehicle air conditioner characterized by the above-mentioned. 6. The method for operating a vehicle air conditioner according to claim 4, wherein the negative pressure tank is configured to apply an assist force to an intake pressure of an intake system and a vehicle foot brake. A method for operating a vehicle air conditioner, wherein the method is determined based on at least one of information of a pressure, a valve opening of a throttle valve of the vehicle engine, and a fuel injection amount of the vehicle engine.