JP2005178560A

JP2005178560A - Freezing cycle device

Info

Publication number: JP2005178560A
Application number: JP2003422062A
Authority: JP
Inventors: Shigeki Oya; 茂貴大矢; Hirotaka Chishiki; 博隆知識; Toshio Tsuboko; 俊夫坪子
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2003-12-19
Filing date: 2003-12-19
Publication date: 2005-07-07

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an air-conditioning function from stopping due to the frost of an evaporator in a freezing cycle device with a compressor that is constituted to control the flow rate of an emission refrigerant by a control signal from the outside like a variable capacity type compressor and an electric compressor. <P>SOLUTION: When a thermal load W of an evaporator is in a frost generating thermal load area, and a first provisional target evaporator temperature TEO1 is smaller than a frost maximum target evaporator temperature TEOH (S1230, S1250), an air-conditioning ECU compares a second target evaporator temperature decided on the basis of a target emission target TAO with a third target evaporator temperature decided on the basis of the outside temperature specified from the thermal load. A higher value is designated as a temporary second provisional target generator temperature TEO2' (S1260), and the second provisional target evaporator temperature TEO2 is calculated on the basis of the temporary second provisional target generator temperature TEO2' and an outside air temperature Tam (S1270), so that the temperature TEO2 is designated as a final target evaporator temperature TEO (S1280). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、吐出流量を変更可能な圧縮機、具体的には吐出容量を変更可能な可変容量型圧縮機、回転数制御可能な電動圧縮機等を備える冷凍サイクル装置における吐出流量制御に関するもので、車両用空調装置に適用して好適なものである。 The present invention relates to a discharge flow rate control in a refrigeration cycle apparatus including a compressor capable of changing a discharge flow rate, specifically, a variable displacement compressor capable of changing a discharge capacity, an electric compressor capable of controlling a rotation speed, and the like. It is suitable for application to a vehicle air conditioner.

従来、蒸発器で液相冷媒全てが蒸発するのに必要な熱量が、蒸発器で実際に液相冷媒が空調空気から奪う（空調空気を冷却する）熱量よりも大きくなる、つまり蒸発器の冷房能力が冷媒負荷よりも勝る場合がある。この時、蒸発器の表面温度が氷点下となり凝縮水が凍結するフロストが発生してしまう。 Conventionally, the amount of heat required for all the liquid-phase refrigerant to evaporate in the evaporator is greater than the amount of heat that the liquid-phase refrigerant actually takes away from the conditioned air (cools the conditioned air) in the evaporator. The capacity may outperform the refrigerant load. At this time, the surface temperature of the evaporator becomes below freezing point, and frost that freezes the condensed water occurs.

フロストが発生すると、蒸発器を空気が通過しにくくなるため、蒸発器よりも空気流れ後流側の蒸発器温度センサの温度が低下しにくくなる。したがって、圧縮機は蒸発器温度センサの温度を低下させようとして、冷媒吐出流量を増大させる。この時、冷凍サイクルの低圧圧力（圧縮機吸入圧）Ｐｓが低下するため、圧縮機が吸入する冷媒の比容積が増大する。冷媒の比容積が増大すると、圧縮機が実質的に吸入する冷媒量が減少するため、冷媒とともに循環するオイル量も不足する。そのため、圧縮機を駆動し続けると最悪の場合には焼きつきを起こしてしまう。 When frost is generated, it is difficult for air to pass through the evaporator, so that the temperature of the evaporator temperature sensor on the downstream side of the air flow is less likely to decrease than the evaporator. Therefore, the compressor increases the refrigerant discharge flow rate in an attempt to decrease the temperature of the evaporator temperature sensor. At this time, since the low pressure (compressor suction pressure) Ps of the refrigeration cycle decreases, the specific volume of the refrigerant sucked by the compressor increases. As the specific volume of the refrigerant increases, the amount of refrigerant substantially sucked by the compressor decreases, so that the amount of oil circulating with the refrigerant also becomes insufficient. For this reason, if the compressor is continuously driven, burn-in occurs in the worst case.

この問題を解消するために、吐出流量を変更可能な可変容量圧縮機を備える車両用空調装置において、蒸発器の冷房能力が最大となる運転モードである車室内の急速冷房を行った後に蒸発器のフロスト判定を行うものが特許文献１にて知られている。 In order to solve this problem, in a vehicle air conditioner equipped with a variable capacity compressor capable of changing the discharge flow rate, after performing rapid cooling of the vehicle interior, which is an operation mode in which the cooling capacity of the evaporator is maximized, the evaporator Japanese Patent Application Laid-Open No. H10-228867 is known for performing the frost determination.

この従来例では、蒸発器通過後の空気の温度を検出する蒸発器温度センサの検出温度と可変容量圧縮機の最大吐出状態とを検出し、可変容量圧縮機が最大吐出状態にも関わらず蒸発器通過後の空気の温度が低下しない場合をフロスト状態と判定している。前述のように蒸発器がフロストすると蒸発器を空気が通過しにくくなり、蒸発器よりも空気流れ後流側の蒸発器温度センサ付近の空気温度が低下しなくなるからである。 In this conventional example, the temperature detected by the evaporator temperature sensor that detects the temperature of the air after passing through the evaporator and the maximum discharge state of the variable capacity compressor are detected, and the variable capacity compressor evaporates regardless of the maximum discharge state. When the temperature of the air after passing through the vessel does not decrease, it is determined as a frost state. This is because when the evaporator is frosted as described above, it becomes difficult for air to pass through the evaporator, and the air temperature in the vicinity of the evaporator temperature sensor on the downstream side of the air flow from the evaporator does not decrease.

そして、蒸発器がフロストしたと判定した場合には、可変容量圧縮機を所定時間停止し、蒸発器のフロストを解除した後に再駆動する。これにより、蒸発器がフロストしている時に可変容量圧縮機を運転し続けてしまい、圧縮機が焼きつくことを防止できる。
特開平５−４２８１９号公報 When it is determined that the evaporator has been frosted, the variable capacity compressor is stopped for a predetermined time, and after the evaporator has been released from frosting, it is restarted. As a result, it is possible to prevent the compressor from being burned by continuing to operate the variable capacity compressor when the evaporator is frosted.
Japanese Patent Laid-Open No. 5-42819

しかし、従来例の車両用空調装置では、フロストしたと判定した場合には可変容量圧縮機が停止してしまうため、停止中は車室内の空調を行うことができないという問題がある。 However, in the conventional vehicle air conditioner, the variable capacity compressor stops when it is determined that the vehicle has been frosted. Therefore, there is a problem that the vehicle interior cannot be air-conditioned while the vehicle is stopped.

本発明は、上記点に鑑み、可変容量圧縮機のごとく吐出流量を変更可能な圧縮機を備えた車両用空調装置において、蒸発器のフロストを防止することにより、空調機能の停止を防ぐことを目的とする。 In view of the above points, the present invention provides a vehicle air conditioner equipped with a compressor capable of changing the discharge flow rate, such as a variable capacity compressor, to prevent the air conditioner from being stopped by preventing the evaporator from being frosted. Objective.

上記目的を達成するため、請求項１に記載の発明では、空調対象空間へ流れる空気の通路を形成するケース（１１）と、ケース（１１）内に配置され、空調対象空間への空気流れを作る送風機（１７）と、吐出冷媒流量を外部からの制御信号（Ｉｎ）により制御可能な構成になっている可変容量圧縮機（１９）と、圧縮機（１９）の吸入側に接続され、空調対象空間へ流れる空気から吸熱して低圧冷媒を蒸発させる蒸発器（１８）と、可変容量圧縮機（１９）の吐出冷媒流量を制御する制御手段（４０）とを備え、
制御手段（４０）は蒸発器（１８）に流入する空気の熱負荷（Ｗ）を算出し、さらに、熱負荷（Ｗ）が予め与えられたフロストが発生する熱負荷領域（Ｆ）内か外かを判定し、
熱負荷（Ｗ）がフロスト発生熱負荷領域（Ｆ）外の場合には、空調対象空間内の熱負荷に基づいて可変容量圧縮機（１９）の吐出冷媒流量を制御し、
熱負荷（Ｗ）がフロスト発生熱負荷領域（Ｆ）内の場合には、可変容量圧縮機（１９）の吐出冷媒流量を空調対象空間内の熱負荷に基づいて算出される吐出冷媒流量よりも少ない流量に制御するようになっていることを特徴としている。 In order to achieve the above object, according to the first aspect of the present invention, a case (11) that forms a passage for air flowing into the air-conditioning target space, and a case (11) that are arranged in the case (11), An air conditioner connected to the suction side of the blower (17) to be made, the variable capacity compressor (19) configured to be able to control the discharged refrigerant flow rate by an external control signal (In), and the compressor (19) An evaporator (18) that absorbs heat from the air flowing into the target space and evaporates the low-pressure refrigerant; and a control means (40) that controls the discharge refrigerant flow rate of the variable capacity compressor (19),
The control means (40) calculates the heat load (W) of the air flowing into the evaporator (18), and further, the heat load (W) is inside or outside the heat load region (F) where the frost generated in advance is generated. Determine whether
When the heat load (W) is outside the frost generation heat load region (F), the discharge refrigerant flow rate of the variable capacity compressor (19) is controlled based on the heat load in the air conditioning target space,
When the heat load (W) is within the frost generation heat load region (F), the discharge refrigerant flow rate of the variable capacity compressor (19) is set to be larger than the discharge refrigerant flow rate calculated based on the heat load in the air-conditioning target space. It is characterized by being controlled to a low flow rate.

これによると、熱負荷（Ｗ）がフロスト発生熱負荷領域（Ｆ）内の場合には、制御手段（４０）が可変容量圧縮機（１９）の吐出冷媒流量を空調対象空間内の熱負荷に基づいて算出される吐出冷媒流量よりも少ない流量に制御するため、蒸発器（１８）で液相冷媒全てが蒸発するのに必要な熱量が小さくなる。つまりフロスト発生熱負荷領域（Ｆ）では蒸発器（１８）の冷房能力を小さくすることができるため、蒸発器（１８）のフロストを防止することができる。 According to this, when the heat load (W) is within the frost generation heat load region (F), the control means (40) changes the refrigerant flow rate discharged from the variable capacity compressor (19) to the heat load in the air conditioning target space. Since the flow rate is controlled to be smaller than the discharge refrigerant flow rate calculated on the basis of the flow rate, the amount of heat necessary for evaporating all the liquid phase refrigerant in the evaporator (18) is reduced. That is, since the cooling capacity of the evaporator (18) can be reduced in the frost generation heat load region (F), the frost of the evaporator (18) can be prevented.

また、請求項２に記載の発明では、冷凍サイクル装置において、空調対象空間へ流れる空気の通路を形成するケース（１１）と、ケース（１１）内に配置され、空調対象空間への空気流れを作る送風機（１７）と、ケース（１１）内に配置され、空調対象空間へ流れる空気から吸熱して低圧冷媒を蒸発させる蒸発器（１８）と、蒸発器（１８）の冷媒流れ下流側に接続され、外部からの制御信号（Ｉｎ）により吐出容量を変更して吐出冷媒流量を制御可能な構成になっている可変容量圧縮機（１９）と、蒸発器（１８）の温度を検出する蒸発器温度検出手段（４１ａ）と、空調対象空間外の空気温度を検出する外気温度検出手段（４１ｃ）と、蒸発器温度検出手段（４１ａ）および外気温度検出手段（４１ｃ）の検出信号が入力され、可変容量圧縮機（１９）へ制御信号（Ｉｎ）を出力する制御手段（４０）とを備え、
制御手段（４０）は、少なくとも外気温検出手段（４１ｃ）の検出温度（Ｔａｍ）により決定される第１目標蒸発器温度（ｆ１（Ｔａｍ））と、空調対象空間へ吹き出す空気の目標吹出温度（ＴＡＯ）により決定される第２目標蒸発器温度（ｆ２（ＴＡＯ））とに基づいて第１暫定目標蒸発器温度（ＴＥＯ１）を算出し、さらに、制御手段（４０）は蒸発器（１８）に流入する空気の熱負荷（Ｗ）と、熱負荷（Ｗ）により決定される第３目標蒸発器温度（ｆ３（Ｗ））とを算出し、
制御手段（４０）には予めフロストが発生する熱負荷領域（Ｆ）が与えられており、
熱負荷（Ｗ）がフロスト発生熱負荷領域（Ｆ）外の場合には、制御手段（４０）は蒸発器温度検出手段（４１ａ）の検出する蒸発器温度（Ｔｅ）が第１暫定目標蒸発器温度（ＴＥＯ１）となるように制御信号（Ｉｎ）を出力し、
熱負荷（Ｗ）がフロスト発生熱負荷領域（Ｆ）内の場合には、制御手段（４０）は少なくとも第２目標蒸発器温度（ｆ２（ＴＡＯ））と第３目標蒸発器温度（ｆ３（Ｗ））とを比較して、高い方の値を仮の第２暫定目標蒸発器温度（ＴＥＯ２’）とし、さらに、制御手段（４０）は少なくとも仮の第２暫定目標蒸発器温度（ＴＥＯ２’）と外気温度検出手段（４１ｃ）の検出温度（Ｔａｍ）とに基づいて第２暫定目標蒸発器温度（ＴＥＯ２）を算出し、蒸発器温度（Ｔｅ）が第２暫定目標蒸発器温度（ＴＥＯ２）となるように制御信号（Ｉｎ）を出力するようになっていることを特徴としている。 Moreover, in invention of Claim 2, it arrange | positions in the case (11) which forms the channel | path of the air which flows into the air-conditioning object space in the refrigeration cycle apparatus, and the case (11), The blower (17) to be made, the evaporator (18) which is disposed in the case (11) and absorbs heat from the air flowing into the air-conditioning target space and evaporates the low-pressure refrigerant, and is connected to the refrigerant flow downstream side of the evaporator (18). And a variable capacity compressor (19) configured to control the discharge refrigerant flow rate by changing the discharge capacity by an external control signal (In), and an evaporator for detecting the temperature of the evaporator (18) Detection signals of the temperature detection means (41a), the outside temperature detection means (41c) for detecting the air temperature outside the air conditioning target space, the evaporator temperature detection means (41a) and the outside air temperature detection means (41c) are input, Variable volume Control means for outputting a control signal to the compressor (19) (an In) and a (40),
The control means (40) includes at least a first target evaporator temperature (f1 (Tam)) determined by the detected temperature (Tam) of the outside air temperature detection means (41c), and a target blowout temperature ( The first provisional target evaporator temperature (TEO1) is calculated based on the second target evaporator temperature (f2 (TAO)) determined by TAO), and the control means (40) further supplies the evaporator (18). Calculating the thermal load (W) of the incoming air and the third target evaporator temperature (f3 (W)) determined by the thermal load (W);
The control means (40) is preliminarily provided with a heat load region (F) where frost is generated,
When the heat load (W) is outside the frost generation heat load region (F), the control means (40) has the evaporator temperature (Te) detected by the evaporator temperature detection means (41a) as the first provisional target evaporator. The control signal (In) is output so that the temperature (TEO1) is reached,
When the heat load (W) is within the frost generation heat load region (F), the control means (40) at least the second target evaporator temperature (f2 (TAO)) and the third target evaporator temperature (f3 (W) )), The higher value is set as a temporary second provisional target evaporator temperature (TEO2 ′), and the control means (40) is at least a provisional second provisional target evaporator temperature (TEO2 ′). And the detected temperature (Tam) of the outside air temperature detecting means (41c), the second provisional target evaporator temperature (TEO2) is calculated, and the evaporator temperature (Te) is calculated from the second provisional target evaporator temperature (TEO2). Thus, the control signal (In) is output.

これによると、熱負荷（Ｗ）がフロスト発生熱負荷領域（Ｆ）内の場合には、制御手段（４０）が目標吹出温度（ＴＡＯ）に基づいて決定される第２目標蒸発器温度（ｆ２（ＴＡＯ））と、熱負荷（Ｗ）に基づいて決定される第３目標蒸発器温度（ｆ３（Ｗ））とを比較して、高い方の値を仮の第２暫定目標蒸発器温度（ＴＥＯ２’）とする。 According to this, when the heat load (W) is in the frost generation heat load region (F), the second target evaporator temperature (f2) determined by the control means (40) based on the target outlet temperature (TAO). (TAO)) and the third target evaporator temperature (f3 (W)) determined based on the thermal load (W), and the higher value is set to the provisional second provisional target evaporator temperature ( TEO2 ′).

これにより、第２目標蒸発器温度（ｆ２（ＴＡＯ））のフロスト熱負荷領域（Ｆ）での蒸発器目標温度を、第３目標蒸発器温度（ｆ３（Ｗ））により、フロストが起きない蒸発器目標温度に高くして仮の第２暫定目標蒸発器温度（ＴＥＯ２’）とすることができる。 Thereby, the evaporator target temperature in the frost heat load region (F) of the second target evaporator temperature (f2 (TAO)) is evaporated by the third target evaporator temperature (f3 (W)). The temperature can be raised to the target temperature of the evaporator to obtain a temporary second provisional target evaporator temperature (TEO2 ′).

したがって、制御手段（４０）が蒸発器温度（Ｔｅ）を第２暫定目標蒸発器温度（ＴＥＯ２）とするように可変容量圧縮機（１９）の吐出冷媒流量を制御しても、蒸発器（１８）にはフロストが発生せず、フロストに起因する可変容量圧縮機（１９）の停止、つまり空調機能の停止を防止することができる。 Therefore, even if the control means (40) controls the discharge refrigerant flow rate of the variable capacity compressor (19) so that the evaporator temperature (Te) becomes the second temporary target evaporator temperature (TEO2), the evaporator (18 ) Does not generate frost, and it is possible to prevent the variable capacity compressor (19) from being stopped due to the frost, that is, the air conditioning function from being stopped.

また、請求項３に記載の発明では、請求項２に記載の冷凍サイクル装置において、制御手段（４０）には、フロスト発生熱負荷領域（Ｆ）における最大の蒸発器温度であるフロスト最大目標蒸発器温度（ＴＥＯＨ）が与えられており、
制御手段（４０）は、熱負荷（Ｗ）がフロスト発生熱負荷領域（Ｆ）内であって、第１暫定目標蒸発器温度（ＴＥＯ１）がフロスト最大目標蒸発器温度（ＴＥＯＨ）以上の場合には、蒸発器温度検出手段（４１ａ）の検出する蒸発器温度（Ｔｅ）が第１暫定目標蒸発器温度（ＴＥＯ１）となるように制御信号（Ｉｎ）を出力し、
一方、熱負荷（Ｗ）がフロスト発生熱負荷領域（Ｆ）内であって、第１暫定目標蒸発器温度（ＴＥＯ１）がフロスト最大目標蒸発器温度（ＴＥＯＨ）より小さい場合には、蒸発器温度検出手段（４１ａ）の検出する蒸発器温度（Ｔｅ）が第２暫定目標蒸発器温度（ＴＥＯ２）となるように制御信号（Ｉｎ）を出力するようになっていることを特徴としている。 According to a third aspect of the present invention, in the refrigeration cycle apparatus according to the second aspect, the control means (40) includes a frost maximum target evaporation which is a maximum evaporator temperature in the frost generation heat load region (F). Temperature of the vessel (TEOH) is given,
When the heat load (W) is within the frost generation heat load region (F) and the first provisional target evaporator temperature (TEO1) is equal to or higher than the frost maximum target evaporator temperature (TEOH), the control means (40) Outputs a control signal (In) so that the evaporator temperature (Te) detected by the evaporator temperature detecting means (41a) becomes the first provisional target evaporator temperature (TEO1),
On the other hand, when the heat load (W) is within the frost generation heat load region (F) and the first provisional target evaporator temperature (TEO1) is smaller than the frost maximum target evaporator temperature (TEOH), the evaporator temperature The control signal (In) is output so that the evaporator temperature (Te) detected by the detection means (41a) becomes the second temporary target evaporator temperature (TEO2).

これにより、熱負荷（Ｗ）がフロスト発生熱負荷領域（Ｆ）内であって、第１暫定目標蒸発器温度（ＴＥＯ１）がフロスト最大目標蒸発器温度（ＴＥＯＨ）未満の場合には、第３目標蒸発器温度（ｆ３（Ｗ））によりフロストが起きないように算出される第２暫定目標蒸発器温度（ＴＥＯ２）を蒸発器の目標温度とすることができる。 Thus, when the heat load (W) is within the frost generation heat load region (F) and the first provisional target evaporator temperature (TEO1) is lower than the frost maximum target evaporator temperature (TEOH), the third The second provisional target evaporator temperature (TEO2) calculated so that frost does not occur due to the target evaporator temperature (f3 (W)) can be used as the target temperature of the evaporator.

なお、第１暫定目標蒸発器温度（ＴＥＯ１）が前記フロスト発生熱負荷領域（Ｆ）における最大の蒸発器温度であるフロスト最大目標蒸発器温度（ＴＥＯＨ）以上の場合には、フロストは発生しないため、蒸発器温度（Ｔｅ）を第１暫定目標蒸発器温度（ＴＥＯ１）を目標として制御すればよい。 Note that frost is not generated when the first provisional target evaporator temperature (TEO1) is equal to or higher than the frost maximum target evaporator temperature (TEOH), which is the maximum evaporator temperature in the frost generation heat load region (F). The evaporator temperature (Te) may be controlled with the first provisional target evaporator temperature (TEO1) as a target.

また、請求項４に記載の発明のように、請求項２または３に記載の冷凍サイクル装置において、制御手段に検出信号が入力され、蒸発器（１８）に流入する空気の温度を検出する流入空気温度検出手段（４１ｃ、４１ｄ）および蒸発器（１８）に流入する空気の湿度を検出する流入空気湿度検出手段（４１ｂ）とを備え、前記制御手段（４０）において、少なくとも流入空気温度検出手段（４１ｃ、４１ｄ）の検出温度（Ｔａｍ、Ｔｒ）、流入空気湿度検出手段（４１ｂ）の検出湿度（ＲＨ）および送風機（１７）の送風量とに基づいて熱負荷（Ｗ）を算出すれば、具体的に蒸発器（１８）への正確な熱負荷（Ｗ）を求めることができる。 Moreover, in the refrigeration cycle apparatus according to claim 2 or 3, as in the invention according to claim 4, the detection signal is input to the control means, and the inflow for detecting the temperature of the air flowing into the evaporator (18). Air temperature detection means (41c, 41d) and inflow air humidity detection means (41b) for detecting the humidity of the air flowing into the evaporator (18), and at least the inflow air temperature detection means in the control means (40). If the thermal load (W) is calculated based on the detected temperatures (Tam, Tr) of (41c, 41d), the detected humidity (RH) of the inflow air humidity detecting means (41b), and the blower volume of the blower (17), Specifically, an accurate heat load (W) to the evaporator (18) can be obtained.

なお、上記各手段の括弧内の符号は、後述する実施形態に記載の具体的手段との対応関係を示すものである。 In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

（第１実施形態）
図１は、第１実施形態の全体構成の概要を示すもので、車両用空調装置は室内空調ユニット１０を備えている。空調ユニット１０は車室内最前部の計器盤（図示せず）の内側部に配設されており、車室内を空調するものである。 (First embodiment)
FIG. 1 shows an outline of the overall configuration of the first embodiment, and the vehicle air conditioner includes an indoor air conditioning unit 10. The air conditioning unit 10 is disposed inside an instrument panel (not shown) at the foremost part of the vehicle interior, and air-conditions the vehicle interior.

空調ユニット１０はケース１１を有し、このケース１１内には車室内へ向かって空気が送風される空気通路が形成されている。このケース１１の空気通路の最上流部には内気導入口１２および外気導入口１３を有する内外気切替箱１４が配置されている。この内外気切替箱１４内には、内外気切替手段としての内外気切替ドア１５が回転自在に配置されている。 The air conditioning unit 10 has a case 11, and an air passage through which air is blown toward the vehicle interior is formed in the case 11. An inside / outside air switching box 14 having an inside air introduction port 12 and an outside air introduction port 13 is disposed at the most upstream portion of the air passage of the case 11. In the inside / outside air switching box 14, an inside / outside air switching door 15 as an inside / outside air switching means is rotatably arranged.

この内外気切替ドア１５はサーボモータ１６によって駆動されるもので、内気導入口１２より内気（車室内空気）を導入する内気導入モードと外気導入口１３より外気（車室外空気）を導入する外気導入モードとを切り替えている。 The inside / outside air switching door 15 is driven by a servo motor 16, and is an inside air introduction mode for introducing inside air (vehicle compartment air) from the inside air introduction port 12 and an outside air for introducing outside air (vehicle compartment outside air) from the outside air introduction port 13. Switching to introduction mode.

内外気切替箱１４の下流側には車室内に向かう空気流を発生させる電動式の送風機１７が配置されている。この送風機１７は、遠心式の送風ファン１７ａがモータ１７ｂにより駆動されるようになっている。送風機１７の下流側にはケース１１内を流れる空気を冷却する蒸発器１８が配置されている。この蒸発器１８は、送風機１７の送風空気を冷却する冷房用熱交換器で、冷凍サイクル装置１００を構成する要素の一つである。 On the downstream side of the inside / outside air switching box 14, an electric blower 17 that generates an air flow toward the passenger compartment is disposed. The blower 17 is configured such that a centrifugal blower fan 17a is driven by a motor 17b. An evaporator 18 that cools the air flowing through the case 11 is disposed on the downstream side of the blower 17. The evaporator 18 is a cooling heat exchanger that cools the air blown from the blower 17 and is one of the elements constituting the refrigeration cycle apparatus 100.

なお、冷凍サイクル装置１００は、圧縮機１９の吐出側から、凝縮器２０、受液器２１および減圧手段をなす膨張弁２２を介して蒸発器１８に冷媒が循環するように形成された周知のものである。また、本実施形態では冷媒としてＨＦＣ−１３４ａを使用している。 Note that the refrigeration cycle apparatus 100 is a well-known configuration in which refrigerant is circulated from the discharge side of the compressor 19 to the evaporator 18 via the condenser 20, the liquid receiver 21 and the expansion valve 22 that serves as a decompression unit. Is. In this embodiment, HFC-134a is used as the refrigerant.

圧縮機１９は、電磁クラッチ１９ａ、プーリ、ベルト等を介して車両エンジン（図示せず）の回転動力が伝達されることにより回転駆動する。また、この圧縮機として、本例では外部からの制御信号により吐出容量を連続的に可変する外部可変容量型圧縮機１９を使用している。 The compressor 19 is rotationally driven by the rotational power of a vehicle engine (not shown) being transmitted through an electromagnetic clutch 19a, a pulley, a belt, and the like. In this example, an external variable capacity compressor 19 that continuously varies the discharge capacity by a control signal from the outside is used as the compressor.

この外部可変容量型圧縮機１９は公知のものであり、例えば、斜板型圧縮機において吐出圧と吸入圧を利用して斜板室の圧力を制御する電磁式圧力制御装置を持つ容量可変装置１９ｂを備えている。この容量可変装置１９ｂで斜板室の圧力を制御することにより、斜板の傾斜角度を可変してピストンのストローク、すなわち圧縮機吐出容量を略０％〜１００％の範囲で連続的に変化させることができる。 The external variable capacity compressor 19 is a known one. For example, a capacity variable device 19b having an electromagnetic pressure control device for controlling the pressure in the swash plate chamber using the discharge pressure and the suction pressure in the swash plate compressor. It has. By controlling the pressure of the swash plate chamber with this capacity changing device 19b, the inclination angle of the swash plate is varied to continuously change the stroke of the piston, that is, the compressor discharge capacity in the range of approximately 0% to 100%. Can do.

この容量可変装置１９ｂの電磁式圧力制御装置は、圧縮機１９の吐出圧と吸入圧を利用して制御圧力（斜板室圧力）を変化させるものであり、制御電流Ｉｎにより電磁力が調節される電磁機構、およびこの電磁機構の電磁力と吸入圧との釣り合いによって変位する弁体を有し、この弁体により圧縮機１９の吐出圧を斜板室内に導く通路の圧損を調節して、制御圧力を変化させるようになっている。 The electromagnetic pressure control device of the capacity variable device 19b changes the control pressure (swash plate chamber pressure) using the discharge pressure and suction pressure of the compressor 19, and the electromagnetic force is adjusted by the control current In. An electromagnetic mechanism and a valve body that is displaced by the balance between the electromagnetic force of the electromagnetic mechanism and the suction pressure, and the pressure loss of the passage that guides the discharge pressure of the compressor 19 into the swash plate chamber is adjusted by this valve body. The pressure is changed.

容量可変装置１９ｂの電磁式圧力制御装置への通電は後述の図３の空調電子制御装置（ＥＣＵ）４０により制御されており、容量可変装置１９ｂの制御電流Ｉｎを増大させると圧縮機吐出容量が増大するようになっている。一方、圧縮機吐出容量が増大すると冷凍サイクルの低圧圧力（吸入圧）Ｐｓは低下する。つまり、容量可変装置１９ｂの制御電流Ｉｎは冷凍サイクルの低圧圧力（吸入圧）Ｐｓを決めており、低圧圧力Ｐｓは制御電流Ｉｎの増加に反比例して低下する（図２参照）。 Energization of the variable capacity device 19b to the electromagnetic pressure control device is controlled by an air conditioning electronic control unit (ECU) 40 shown in FIG. 3 described later. When the control current In of the variable capacity device 19b is increased, the compressor discharge capacity is increased. It is going to increase. On the other hand, when the compressor discharge capacity increases, the low pressure (suction pressure) Ps of the refrigeration cycle decreases. That is, the control current In of the variable capacity device 19b determines the low pressure (intake pressure) Ps of the refrigeration cycle, and the low pressure Ps decreases in inverse proportion to the increase in the control current In (see FIG. 2).

従って、制御電流Ｉｎの増減により圧縮機１９の吐出容量、ひいては吐出冷媒流量が増減して実際の低圧圧力Ｐｓを上下させて、蒸発器１８の温度（蒸発器吹出温度Ｔｅ）が所定の最終目標温度ＴＥＯ（低圧圧力Ｐｓの目標圧力に対応した温度）となるように蒸発器１８の冷却能力を制御できる。ここで、制御電流Ｉｎは具体的にはデューティ制御により可変するが、制御電流Ｉｎの値をデューティ制御によらず直接連続的（アナログ的）に増減してもよい。 Accordingly, the discharge capacity of the compressor 19 and thus the discharge refrigerant flow rate are increased or decreased by increasing or decreasing the control current In to raise or lower the actual low pressure Ps, and the temperature of the evaporator 18 (evaporator outlet temperature Te) becomes a predetermined final target. The cooling capacity of the evaporator 18 can be controlled to be the temperature TEO (temperature corresponding to the target pressure of the low pressure Ps). Here, the control current In is specifically variable by duty control, but the value of the control current In may be directly increased / decreased independently of the duty control.

また、斜板式可変容量型圧縮機１９は制御圧Ｐｃの調整により吐出容量を１００％から略０％付近まで連続的に変化させることができる。そして、吐出容量を略０％付近に減少することにより、圧縮機１９が実質的に作動停止状態になる。したがって、圧縮機１９の回転軸をプーリ、ベルト等を介して車両エンジン側のプーリに常時連結するクラッチレスの構成とすることができる。 Further, the swash plate type variable displacement compressor 19 can continuously change the discharge capacity from 100% to approximately 0% by adjusting the control pressure Pc. Then, by reducing the discharge capacity to approximately 0%, the compressor 19 is substantially stopped. Therefore, a clutchless configuration in which the rotation shaft of the compressor 19 is always coupled to the vehicle engine side pulley via a pulley, a belt, or the like can be achieved.

ところで、図１の冷凍サイクル装置１００では、冷媒が圧縮機１９により高温高圧に圧縮され、この圧縮機１９から吐出された高温高圧の冷媒は凝縮器（放熱器）２０に導入される。この凝縮器２０にてガス冷媒は冷却用電動ファン２０ａにより送風される外気へ放熱して凝縮する。凝縮器２０を通過した冷媒は受液器２１で気相冷媒と液相冷媒とに分離され、この液相冷媒は受液器２１内に貯留される。 In the refrigeration cycle apparatus 100 of FIG. 1, the refrigerant is compressed to high temperature and high pressure by the compressor 19, and the high temperature and high pressure refrigerant discharged from the compressor 19 is introduced into the condenser (heat radiator) 20. In this condenser 20, the gas refrigerant dissipates heat to the outside air blown by the cooling electric fan 20a and condenses. The refrigerant that has passed through the condenser 20 is separated into a gas-phase refrigerant and a liquid-phase refrigerant by a liquid receiver 21, and the liquid-phase refrigerant is stored in the liquid receiver 21.

受液器２１からの高圧液冷媒は温度式膨張弁２２にて低圧の気液２相状態に減圧され、この減圧後の低圧冷媒は上記の蒸発器１８において空調空気から吸熱して蒸発するようになっている。蒸発器１８において蒸発した後のガス冷媒は再度、圧縮機１９に吸入され、圧縮される。 The high-pressure liquid refrigerant from the liquid receiver 21 is decompressed to a low-pressure gas-liquid two-phase state by the temperature type expansion valve 22, and the decompressed low-pressure refrigerant absorbs heat from the conditioned air and evaporates in the evaporator 18. It has become. The gas refrigerant evaporated in the evaporator 18 is again sucked into the compressor 19 and compressed.

なお、温度式膨張弁２２は周知のごとく蒸発器出口の冷媒過熱度が所定値に維持されるように弁開度を自動調節するものである。冷凍サイクル装置１００のうち、圧縮機１９、凝縮器２０、受液器２１等の機器は、車両エンジンルーム（図示せず）内に配置されている。 As is well known, the temperature type expansion valve 22 automatically adjusts the valve opening so that the degree of refrigerant superheat at the evaporator outlet is maintained at a predetermined value. Of the refrigeration cycle apparatus 100, devices such as the compressor 19, the condenser 20, and the liquid receiver 21 are disposed in a vehicle engine room (not shown).

一方、空調ユニット１０において、蒸発器１８の下流側にはケース１１内を流れる空気を加熱するヒータコア２３が配置されている。このヒータコア２３は車両エンジンの温水（エンジン冷却水）を熱源として、蒸発器１８通過後の空気（冷風）を加熱する暖房用熱交換器であり、その側方にはヒータコア２３をバイパスして空気が流れるバイパス通路２４が形成されている。 On the other hand, in the air conditioning unit 10, a heater core 23 for heating the air flowing in the case 11 is disposed on the downstream side of the evaporator 18. The heater core 23 is a heating heat exchanger that heats the air (cold air) that has passed through the evaporator 18 using warm water (engine cooling water) of the vehicle engine as a heat source, and bypasses the heater core 23 to the side of the air. Is formed.

蒸発器１８とヒータコア２３との間には、エアミックスドア２５が回転自在に配置されている。このエアミックスドア２５はサーボモータ２６により駆動されており、その回転位置（開度）が連続的に調節可能になっている。エアミックスドア２５の開度によりヒータコア２３を通る空気量（温風量）と、バイパス通路２４を通過してヒータコア２３をバイパスする空気量（冷風量）とを調節し、これにより、車室内に吹き出す空気の温度を調節するようになっている。 An air mix door 25 is rotatably disposed between the evaporator 18 and the heater core 23. The air mix door 25 is driven by a servo motor 26, and its rotational position (opening degree) can be continuously adjusted. The amount of air passing through the heater core 23 (warm air amount) and the amount of air passing through the bypass passage 24 and bypassing the heater core 23 (cold air amount) are adjusted by the opening degree of the air mix door 25, thereby blowing out into the vehicle interior. The temperature of the air is adjusted.

ケース１１の空気通路の最下流部には、車両の前面窓ガラスＷＳに向けて空調風を吹き出すためのデフロスタ吹出口２７、乗員の顔部に向けて空調風を吹き出すためのフェイス吹出口２８、および乗員の足元部に向けて空調風を吹き出すためのフット吹出口２９の計３種類の吹出口が設けられている。 A defroster outlet 27 for blowing conditioned air toward the front window glass WS of the vehicle, a face outlet 28 for blowing conditioned air toward the occupant's face, at the most downstream portion of the air passage of the case 11, A total of three types of air outlets 29 are provided, that is, a foot air outlet 29 for blowing air-conditioned air toward the feet of the passenger.

これら吹出口２７〜２９の上流部にはデフロスタドア３０、フェイスドア３１およびフットドア３２が回転自在に配置されている。これらのドア３０〜３２は、図示しないリンク機構を介して共通のサーボモータ３３によって開閉操作される。 A defroster door 30, a face door 31, and a foot door 32 are rotatably disposed upstream of the air outlets 27 to 29. These doors 30 to 32 are opened and closed by a common servo motor 33 through a link mechanism (not shown).

次に、図３により本実施形態の電気制御部の概要を説明すると、空調電子制御装置（ＥＣＵ）４０は本発明の制御手段を構成するものであり、ＣＰＵ、ＲＯＭおよびＲＡＭ等を含む周知のマイクロコンピュータとその周辺回路から構成される。この空調ＥＣＵ４０は、そのＲＯＭ内に空調制御のための制御プログラムを記憶しており、その制御プログラムに基づいて各種演算、処理を行う。空調ＥＣＵ４０の入力側にはセンサ群４１からのセンサ検出信号、空調パネル４２からの操作信号が入力される。 Next, the outline of the electric control unit of the present embodiment will be described with reference to FIG. It consists of a microcomputer and its peripheral circuits. The air conditioning ECU 40 stores a control program for air conditioning control in its ROM, and performs various calculations and processes based on the control program. A sensor detection signal from the sensor group 41 and an operation signal from the air conditioning panel 42 are input to the input side of the air conditioning ECU 40.

センサ群４１には、蒸発器１８の空気吹出部に配置されて蒸発器吹出空気温度Ｔｅを検出する蒸発器温度センサ４１ａが設けられており、この蒸発器温度センサ４１ａの他に、吸込み空気湿度ＲＨ、外気温Ｔａｍ、内気温Ｔｒ、日射量Ｔｓ、温水温度Ｔｗ等を検出する各種のセンサ４１ｂ〜４１ｆ等が備えられている。 The sensor group 41 is provided with an evaporator temperature sensor 41a that is disposed in the air outlet of the evaporator 18 and detects the evaporator outlet air temperature Te. In addition to the evaporator temperature sensor 41a, the intake air humidity Various sensors 41b to 41f for detecting RH, outside air temperature Tam, inside air temperature Tr, solar radiation amount Ts, hot water temperature Tw and the like are provided.

空調パネル４２は、車室内の運転席前方の計器盤（図示せず）付近に配置されるものであって、乗員により操作される以下の操作スイッチ４２ａ〜４２ｅを有する。温度設定スイッチ４２ａは車室内の設定温度の信号を出すものであり、内外気切替スイッチ４２ｂは内外気切替ドア１５による内気モードと外気モードをマニュアル設定する信号を出すものである。 The air conditioning panel 42 is disposed in the vicinity of an instrument panel (not shown) in front of the driver's seat in the passenger compartment, and includes the following operation switches 42a to 42e that are operated by a passenger. The temperature setting switch 42a outputs a signal of the set temperature in the passenger compartment, and the inside / outside air switching switch 42b outputs a signal for manually setting the inside air mode and the outside air mode by the inside / outside air switching door 15.

吹出モードスイッチ４２ｃは吹出モードとして周知のフェイスモード、バイレベルモード、フットモード、フットデフロスタモードおよびデフロスタモードをマニュアル設定するための信号を出すものである。風量切替スイッチ４２ｄは送風機１７のオンオフおよび送風機１７の風量切替をマニュアル設定するための信号を出すものである。 The blowout mode switch 42c outputs a signal for manually setting a face mode, a bi-level mode, a foot mode, a foot defroster mode, and a defroster mode known as blowout modes. The air volume changeover switch 42d outputs a signal for manually setting on / off of the blower 17 and airflow change of the blower 17.

エアコンスイッチ４２ｅは圧縮機１９の作動状態と停止状態を切り替えるものであり、エアコンスイッチ４２ｅをオフ状態にすると制御電流Ｉｎを強制的に０にして、圧縮機１９の吐出容量を略０容量にし、圧縮機１９が実質的に停止状態となる。エアコンスイッチ４２ｅをオン状態にすると、空調ＥＣＵ４０で演算された所定の制御電流Ｉｎが出力される状態となって、圧縮機１９が作動状態となる。 The air conditioner switch 42e switches between the operating state and the stopped state of the compressor 19. When the air conditioner switch 42e is turned off, the control current In is forcibly set to 0, and the discharge capacity of the compressor 19 is set to substantially 0 capacity. The compressor 19 is substantially stopped. When the air conditioner switch 42e is turned on, a predetermined control current In calculated by the air conditioning ECU 40 is output, and the compressor 19 is activated.

空調ＥＣＵ４０の出力側には、圧縮機１９の電磁クラッチ１９ａ、容量可変装置１９ｂ、各機器の電気駆動手段をなすサーボモータ１６、２６、３３、送風機１７のモータ１７ｂおよび電動ファン２０ａ等が接続され、これらの機器の作動が空調ＥＣＵ４０の出力信号により制御される。 Connected to the output side of the air conditioning ECU 40 are an electromagnetic clutch 19a of the compressor 19, a variable capacity device 19b, servo motors 16, 26, 33 that form electric drive means for each device, a motor 17b of the blower 17, an electric fan 20a, and the like. The operation of these devices is controlled by the output signal of the air conditioning ECU 40.

次に、上記構成において本実施形態の作動を説明する。最初に、車両用空調置としての作動の概要を説明すると、空調パネル４２の風量切替スイッチ４２ｄを投入して送風機１７を作動させることにより、空調ユニット１０内の通風路に空気が送風される。 Next, the operation of this embodiment in the above configuration will be described. First, the outline of the operation as the vehicle air conditioner will be described. By turning on the air volume switching switch 42d of the air conditioning panel 42 and operating the blower 17, air is blown into the ventilation path in the air conditioning unit 10.

そして、空調パネル４２の圧縮機作動スイッチであるエアコンスイッチ４２ｅを投入すると、空調ＥＣＵ４０により電磁クラッチ１９ａに通電されて電磁クラッチ１９ａが接続状態となり、圧縮機１９が車両エンジンにより回転駆動される。また、空調ＥＣＵ４０により圧縮機１９の容量可変装置１９ｂの制御電流Ｉｎが後述の図４の制御フローチャートにより決定され、圧縮機１９が所定の吐出容量の状態にて作動する。これにより、冷凍サイクル１００において蒸発器１８に冷媒が循環するので、送風空気を蒸発器１８により冷却、除湿して、車室内へ空調風を吹き出すことができる。 When the air conditioner switch 42e which is a compressor operation switch of the air conditioning panel 42 is turned on, the electromagnetic clutch 19a is energized by the air conditioning ECU 40, the electromagnetic clutch 19a is connected, and the compressor 19 is rotationally driven by the vehicle engine. Further, the control current In of the capacity variable device 19b of the compressor 19 is determined by the air conditioning ECU 40 according to the control flowchart of FIG. 4 described later, and the compressor 19 operates in a state of a predetermined discharge capacity. Thereby, since the refrigerant circulates in the evaporator 18 in the refrigeration cycle 100, the blown air can be cooled and dehumidified by the evaporator 18, and the conditioned air can be blown into the passenger compartment.

次に、図４により空調ＥＣＵ４０により実行される容量制御全体の概要を説明すると、まず、空調ＥＣＵ４０はステップＳ１００にてセンサ群４１の検出信号、操作パネル４２からの操作信号等を読み込む。次に、ステップＳ１１０にて車室内への吹出空気の目標吹出温度ＴＡＯを算出する。この目標吹出温度ＴＡＯは空調熱負荷変動にかかわらず、操作パネル４２の温度設定スイッチ４２ａにより乗員が設定した設定温度Ｔｓｅｔに車室内を維持するために必要な車室内への吹出空気温度であって、ＴＡＯは公知のごとく設定温度Ｔｓｅｔ、外気温Ｔａｍ、内気温Ｔｒ、日射量Ｔｓに基づいて算出する。 Next, the overall capacity control executed by the air conditioning ECU 40 will be described with reference to FIG. 4. First, in step S100, the air conditioning ECU 40 reads a detection signal from the sensor group 41, an operation signal from the operation panel 42, and the like. Next, the target blowing temperature TAO of the blowing air into the vehicle interior is calculated in step S110. This target air temperature TAO is the temperature of air blown into the vehicle interior required to maintain the vehicle interior at the set temperature Tset set by the occupant by the temperature setting switch 42a of the operation panel 42 regardless of the air conditioning thermal load fluctuation. TAO is calculated based on the set temperature Tset, the outside air temperature Tam, the inside air temperature Tr, and the solar radiation amount Ts as is well known.

次に、ステップＳ１２０にて蒸発器１８の最終目標蒸発器温度ＴＥＯを算出する。この最終目標蒸発器温度ＴＥＯは蒸発器吹出空気Ｔｅの目標温度であり、詳細は後述する。その後、ステップＳ１３０にて、圧縮機容量制御のための制御電流Ｉｎを算出する。 Next, the final target evaporator temperature TEO of the evaporator 18 is calculated in step S120. The final target evaporator temperature TEO is a target temperature of the evaporator blown air Te, and will be described in detail later. Thereafter, in step S130, a control current In for compressor capacity control is calculated.

この制御電流Ｉｎは前述の図２に示すように圧縮機１９の容量可変装置１９ｂにおける電磁式圧力制御装置の目標低圧圧力を決定するものであって、制御電流Ｉｎは、蒸発器温度センサ４１ａにより検出される実際の蒸発器吹出空気温度Ｔｅが上記最終目標蒸発器温度ＴＥＯとなるように決定される。なお、蒸発器温度センサ４１ａは、本実施形態のように蒸発器１８から吹出空気の温度を検出してもよいが、直接蒸発器１８の表面温度を検出するものでもよい。 This control current In determines the target low pressure of the electromagnetic pressure control device in the capacity variable device 19b of the compressor 19 as shown in FIG. 2, and the control current In is controlled by the evaporator temperature sensor 41a. The actual evaporator blown air temperature Te detected is determined to be the final target evaporator temperature TEO. The evaporator temperature sensor 41a may detect the temperature of the air blown from the evaporator 18 as in the present embodiment, but may directly detect the surface temperature of the evaporator 18.

次に、ステップＳ１４０にて上記の制御電流Ｉｎが容量可変装置１９ｂに出力され、圧縮機１９の容量制御が実行される。 Next, in step S140, the control current In is output to the variable capacity device 19b, and the capacity control of the compressor 19 is executed.

図５は図４の基本制御ルーチンにおける最終目標蒸発器温度ＴＥＯの算出ステップＳ１２０の具体例を示すものである。まず、Ｓ１２１０では、外気温Ｔａｍに基づいて決定される第１目標蒸発器温度ｆ１（Ｔａｍ）と、車室内への目標吹出し温度ＴＡＯに基づいて決定される第２目標蒸発器温度ｆ２（ＴＡＯ）のうち、低い方の温度を第１暫定目標蒸発器温度ＴＥＯ１として算出する。すなわち、ＴＥＯ１＝ＭＩＮ｛ｆ１（Ｔａｍ）、ｆ２（ＴＡＯ）｝である（図６参照）。 FIG. 5 shows a specific example of the calculation step S120 of the final target evaporator temperature TEO in the basic control routine of FIG. First, in S1210, the first target evaporator temperature f1 (Tam) determined based on the outside air temperature Tam and the second target evaporator temperature f2 (TAO) determined based on the target outlet temperature TAO into the passenger compartment. Of these, the lower temperature is calculated as the first provisional target evaporator temperature TEO1. That is, TEO1 = MIN {f1 (Tam), f2 (TAO)} (see FIG. 6).

ここで、第１目標蒸発器温度ｆ１（Ｔａｍ）は外気温Ｔａｍに応じて決定される。具体的には、外気温Ｔａｍが所定の第１中間温度Ｔ１（例えば、８℃付近）より上昇すると、第１目標蒸発器温度ｆ１（Ｔａｍ）を最低温度（例えば、３℃）から次第に上昇させ、外気温Ｔａｍが所定の第２中間温度Ｔ２（例えば、２３℃付近）まで上昇すると、第１目標蒸発器温度ｆ１（Ｔａｍ）が最高温度（例えば、９℃）となる。これにより、中間温度域における圧縮機動力の低減を図ることができる。 Here, the first target evaporator temperature f1 (Tam) is determined according to the outside air temperature Tam. Specifically, when the outside air temperature Tam rises above a predetermined first intermediate temperature T1 (eg, around 8 ° C.), the first target evaporator temperature f1 (Tam) is gradually raised from the lowest temperature (eg, 3 ° C.). When the outside air temperature Tam rises to a predetermined second intermediate temperature T2 (for example, around 23 ° C.), the first target evaporator temperature f1 (Tam) becomes the maximum temperature (for example, 9 ° C.). Thereby, reduction of the compressor power in an intermediate temperature range can be aimed at.

なお、外気温Ｔａｍが第１中間温度Ｔ１より低い低外気温時に第１目標蒸発器温度ｆ１（Ｔａｍ）を最低温度（例えば、３℃）にしている理由は、低外気温時における窓ガラスＷＳ防曇のための蒸発器除湿能力を確保するためである。 The reason why the first target evaporator temperature f1 (Tam) is set to the lowest temperature (eg, 3 ° C.) when the outside air temperature Tam is lower than the first intermediate temperature T1 is that the window glass WS when the outside air temperature is low. This is to ensure the evaporator dehumidifying ability for anti-fogging.

また、第２目標蒸発器温度ｆ２（ＴＡＯ）は目標吹出温度ＴＡＯの上昇に応じて上昇するように決定される。具体的には、目標吹出温度ＴＡＯが第１所定温度Ｔ３（例えば、７℃付近）より上昇すると、第２目標蒸発器温度ｆ２（ＴＡＯ）を最低温度（例えば、３℃）から次第に上昇させ、目標吹出温度ＴＡＯが第２所定温度Ｔ４（例えば、３６℃付近）まで上昇すると、第２目標蒸発器温度ｆ２（ＴＡＯ）が最高温度（例えば、９℃）となる。 In addition, the second target evaporator temperature f2 (TAO) is determined so as to increase as the target blowing temperature TAO increases. Specifically, when the target blowing temperature TAO rises from the first predetermined temperature T3 (eg, around 7 ° C.), the second target evaporator temperature f2 (TAO) is gradually raised from the lowest temperature (eg, 3 ° C.), When the target blowing temperature TAO rises to the second predetermined temperature T4 (for example, around 36 ° C.), the second target evaporator temperature f2 (TAO) becomes the maximum temperature (for example, 9 ° C.).

なお、所定温度Ｔ３’、Ｔ４’はそれぞれ第１、第２所定温度Ｔ３、Ｔ４より所定温度（本実施形態では５℃）低い温度であり、制御のハンチング防止のためのヒステリシス幅を設定するためのものである。空調ＥＣＵ４０の制御は第１暫定目標蒸発器温度ＴＥＯ１の決定後、Ｓ１２２０へ進む。 Note that the predetermined temperatures T3 ′ and T4 ′ are lower than the first and second predetermined temperatures T3 and T4 by a predetermined temperature (5 ° C. in the present embodiment), respectively, in order to set a hysteresis width for preventing control hunting. belongs to. The control of the air conditioning ECU 40 proceeds to S1220 after determining the first provisional target evaporator temperature TEO1.

図５のＳ１２２０では蒸発器１８への熱負荷Ｗが算出される。具体的には空調ＥＣＵ４０は、外気導入モードの場合には外気温センサ４１ｃの検出する外気温度Ｔａｍを蒸発器１８に流入する空気温度とし、一方、内気導入モード時には内気温センサ４１ｄの検出する内気温度Ｔｒを蒸発器１８に流入する空気温度とする。さらに、この空器温度と吸込み空気湿度センサ４１ｂの検出する湿度ＲＨおよび送風機１７のモータ１７ｂの回転数（＝風量）とを掛けた値を蒸発器１８への熱負荷Ｗとしている。空調ＥＣＵ４０の制御は熱負荷Ｗの算出後、Ｓ１２３０へ進む。 In S1220 of FIG. 5, the heat load W on the evaporator 18 is calculated. Specifically, in the outside air introduction mode, the air conditioning ECU 40 sets the outside air temperature Tam detected by the outside air temperature sensor 41c as the air temperature flowing into the evaporator 18, while in the inside air introduction mode, the inside air detected by the inside air temperature sensor 41d. The temperature Tr is set as the temperature of the air flowing into the evaporator 18. Further, a value obtained by multiplying the empty room temperature by the humidity RH detected by the intake air humidity sensor 41b and the rotational speed (= air volume) of the motor 17b of the blower 17 is set as a heat load W on the evaporator 18. The control of the air conditioning ECU 40 proceeds to S1230 after calculating the heat load W.

Ｓ１２３０では、熱負荷ＷがＷ（ｍｉｎ）より大きくＷ（ｍａｘ）よりも小さいかの判断が行われる。Ｗ（ｍｉｎ）からＷ（ｍａｘ）の間は後述するフロスト熱負荷領域Ｆである。熱負荷Ｗがフロスト熱負荷領域Ｆ以外であると判定された場合には、処理がＳ１２４０へと進む。Ｓ１２４０では、最終目標蒸発器温度ＴＥＯを第１暫定目標蒸発器温度ＴＥＯ１としてＳ１３０へ進むようになっている。一方、熱負荷Ｗがフロスト熱負荷領域Ｆであると判定された場合には、処理がＳ１２５０へと進む。 In S1230, it is determined whether the thermal load W is larger than W (min) and smaller than W (max). Between W (min) and W (max) is a frost heat load region F described later. If it is determined that the thermal load W is outside the frost thermal load region F, the process proceeds to S1240. In S1240, the final target evaporator temperature TEO is set as the first provisional target evaporator temperature TEO1, and the process proceeds to S130. On the other hand, if it is determined that the thermal load W is in the frost thermal load region F, the process proceeds to S1250.

Ｓ１２５０では、第１暫定目標蒸発器温度ＴＥＯ１がフロスト最大目標蒸発器温度ＴＥＯＨ（＝５℃）より小さいかどうかが判定される。第１暫定目標蒸発器温度ＴＥＯ１がフロスト最大目標蒸発器温度ＴＥＯＨより大きい場合は処理がＳ１２４０へ進み、最終目標蒸発器温度ＴＥＯを第１暫定目標蒸発器温度ＴＥＯ１とした後にＳ１３０へ進むようになっている。 In S1250, it is determined whether or not the first provisional target evaporator temperature TEO1 is lower than the frost maximum target evaporator temperature TEOH (= 5 ° C.). When the first temporary target evaporator temperature TEO1 is higher than the frost maximum target evaporator temperature TEOH, the process proceeds to S1240, and after the final target evaporator temperature TEO is set to the first temporary target evaporator temperature TEO1, the process proceeds to S130. ing.

詳細は後述するが第１暫定目標蒸発器温度ＴＥＯ１がフロスト最大目標蒸発器温度ＴＥＯＨ以上の時にはフロストが発生しないためである。一方、第１暫定目標蒸発器温度ＴＥＯ１がフロスト最大目標蒸発器温度ＴＥＯＨより小さいと判定された場合には、処理がＳ１２６０へと進む。 Although details will be described later, frost is not generated when the first provisional target evaporator temperature TEO1 is equal to or higher than the frost maximum target evaporator temperature TEOH. On the other hand, if it is determined that the first temporary target evaporator temperature TEO1 is lower than the frost maximum target evaporator temperature TEOH, the process proceeds to S1260.

ここで、図８により第１暫定目標蒸発器温度ＴＥＯ１のみで可変容量圧縮機１９を制御した場合の蒸発器への熱負荷Ｗと冷凍サイクルの低圧圧力Ｐｓとの関係を述べると、図中白菱形はＴＥＯ３℃、蒸発器１８への最大風量（５００ｍ³／ｈ（ｈ＝時間））での実測値である。同様に白四角はＴＥＯ２℃、白三角はＴＥＯ１℃とした時の実測値である。また、図中バツ印はフロストが発生したことを表し、黒三角はフロストが発生していないことを示している。また、各種点線はＴＥＯ＝３、４、５℃の時の実測値に基づいて最小二乗近似法などにより決定される近似直線を表している。 Here, the relationship between the heat load W to the evaporator and the low pressure Ps of the refrigeration cycle when the variable capacity compressor 19 is controlled only by the first provisional target evaporator temperature TEO1 will be described with reference to FIG. A rhombus is a measured value at TEO 3 ° C. and the maximum air flow rate to the evaporator 18 (500 m ³ / h (h = hour)). Similarly, white squares are measured values when TEO 2 ° C. and white triangles are TEO 1 ° C. In addition, the cross mark in the figure indicates that frost has occurred, and the black triangle indicates that frost has not occurred. Further, various dotted lines represent approximate straight lines determined by the least square approximation method or the like based on measured values when TEO = 3, 4, 5 ° C.

ＴＥＯ３℃の近似直線（点線）で説明すると、ＴＥＯ３℃点線は蒸発器１８への熱負荷Ｗが大きくなるに従い低圧圧力Ｐｓが下降していく。これは、熱負荷Ｗが大きくなると蒸発器温度Ｔｅが高くなり、目標蒸発器温度ＴＥＯ（この場合は３℃）との差が大きくなるため、空調ＥＣＵ４０が冷媒の流量を増やす（低圧圧力Ｐｓを下げる）ためである。 To explain with an approximate straight line (dotted line) of TEO 3 ° C., the low pressure Ps of the TEO 3 ° C. dotted line decreases as the heat load W on the evaporator 18 increases. This is because the evaporator temperature Te increases as the heat load W increases, and the difference from the target evaporator temperature TEO (3 ° C. in this case) increases, so the air conditioning ECU 40 increases the flow rate of the refrigerant (the low pressure Ps is decreased). To lower).

ここで、本発明者らは第１暫定目標蒸発器温度ＴＥＯ１のみで可変容量圧縮機１９を制御するとフロストが発生する熱負荷領域があることを確認した。そこで、本発明者らはフロストが発生しないことが確認された黒三角よりも低圧圧力が高い場合をフロストが発生しない領域ＳＡとして特定した。 Here, the present inventors have confirmed that there is a heat load region in which frost is generated when the variable capacity compressor 19 is controlled only by the first provisional target evaporator temperature TEO1. Therefore, the present inventors have identified the case where the low pressure is higher than the black triangle in which frost is confirmed not to occur as the region SA where frost does not occur.

そして、フロストが発生しない黒三角の低圧圧力ＰｓＬとＴＥＯの近似直線が交わった点の下限熱負荷Ｗ（ｍｉｎ）および上限熱負荷Ｗ（ｍａｘ）を求め、この間の熱負荷領域をフロスト熱負荷領域Ｆとした。図８に示すように上限熱負荷Ｗ（ｍａｘ）でのフロスト上限目標蒸発器温度ＴＥＯＨは５℃、下限熱負荷Ｗ（ｍｉｎ）でのフロスト下限蒸発器温度ＴＥＯＬは３℃である。なお、今回はＴＥＯＬを３℃としている。 Then, the lower limit heat load W (min) and the upper limit heat load W (max) at the point where the black triangular low pressure PsL where no frost occurs and the approximate straight line of TEO intersect are obtained, and the heat load area between these is determined as the frost heat load area. F. As shown in FIG. 8, the frost upper limit target evaporator temperature TEOH at the upper limit heat load W (max) is 5 ° C., and the frost lower limit evaporator temperature TEOL at the lower limit heat load W (min) is 3 ° C. In addition, TEOL is 3 degreeC this time.

これにより、図７のように第３目標蒸発器温度ｆ３（Ｗ）が求められる。つまり、熱負荷Ｗが所定の第１中間熱負荷Ｗ（ｍｉｎ）より上昇すると、第３目標蒸発器温度ｆ３（Ｗ）を下限ＴＥＯＬ（＝３℃）から次第に上昇させ、熱負荷Ｗが所定の第２熱負荷Ｗ（ｍａｘ）まで上昇すると、第３目標蒸発器温度ｆ３（Ｗ）が上限ＴＥＯＨ（＝５℃）で決定される。 Thus, the third target evaporator temperature f3 (W) is obtained as shown in FIG. That is, when the heat load W rises above the predetermined first intermediate heat load W (min), the third target evaporator temperature f3 (W) is gradually increased from the lower limit TEOL (= 3 ° C.), and the heat load W is increased to the predetermined value. When the temperature rises to the second heat load W (max), the third target evaporator temperature f3 (W) is determined by the upper limit TEOH (= 5 ° C.).

図５に戻り、第１暫定目標蒸発器温度ＴＥＯ１がフロスト最大目標蒸発器温度ＴＥＯＨより小さいと判定された場合のＳ１２６０を説明すると、Ｓ１２６０では仮の第２暫定目標蒸発器温度ＴＥＯ２’を算出する。具体的には、第２目標蒸発器温度ｆ２（ＴＡＯ）と、熱負荷Ｗに基づいて決定される第３目標蒸発器温度ｆ３（Ｗ）のうち、大きい方の温度を仮の第２暫定目標蒸発器温度ＴＥＯ２’として算出している。すなわち、ＴＥＯ２’＝ＭＡＸ｛ｆ２（ＴＡＯ）、ｆ３（Ｗ）｝である（図７参照）。仮の第２暫定目標蒸発器温度ＴＥＯ２’の算出後、処理はＳ１２７０へと進む。 Returning to FIG. 5, S1260 when it is determined that the first provisional target evaporator temperature TEO1 is lower than the frost maximum target evaporator temperature TEOH will be described. In S1260, a provisional second provisional target evaporator temperature TEO2 ′ is calculated. . Specifically, the larger one of the second target evaporator temperature f2 (TAO) and the third target evaporator temperature f3 (W) determined based on the heat load W is set as a temporary second provisional target. It is calculated as the evaporator temperature TEO2 ′. That is, TEO2 '= MAX {f2 (TAO), f3 (W)} (see FIG. 7). After calculating the provisional second provisional target evaporator temperature TEO2 ', the process proceeds to S1270.

Ｓ１２７０では、空調ＥＣＵ４０が第２暫定目標蒸発器温度ＴＥＯ２を算出する。具体的には、仮の第２暫定目標蒸発器温度ＴＥＯ２’と第１蒸発器温度ｆ１（Ｔａｍ）のうち、低い方の温度を第２暫定目標蒸発器温度ＴＥＯ２として算出する。すなわち、ＴＥＯ２＝ＭＩＮ｛ＴＥＯ２’、ｆ１（Ｔａｍ）｝である。そして、Ｓ１２７０で第２暫定目標蒸発器温度ＴＥＯ２を最終目標蒸発器温度ＴＥＯとした後にＳ１３０へ処理を進める。その後は、前述した制御と同じである。 In S1270, the air conditioning ECU 40 calculates the second provisional target evaporator temperature TEO2. Specifically, the lower one of the temporary second provisional target evaporator temperature TEO2 'and the first evaporator temperature f1 (Tam) is calculated as the second provisional target evaporator temperature TEO2. That is, TEO2 = MIN {TEO2 ', f1 (Tam)}. In step S1270, the second provisional target evaporator temperature TEO2 is set to the final target evaporator temperature TEO, and then the process proceeds to step S130. Thereafter, the control is the same as that described above.

次に、第１実施形態による作用効果を述べると、熱負荷Ｗがフロスト発生熱負荷領域Ｆ内の場合には、空調ＥＣＵ４０が目標吹出温度ＴＡＯに基づいて決定される第２目標蒸発器温度ｆ２（ＴＡＯ）と、熱負荷Ｗに基づいて決定される第３目標蒸発器温度ｆ３Ｗとを比較して、高い方の値を仮の第２暫定目標蒸発器温度ＴＥＯ２’とする。 Next, the operational effects according to the first embodiment will be described. When the thermal load W is within the frost generation thermal load region F, the second target evaporator temperature f2 determined by the air conditioning ECU 40 based on the target blowing temperature TAO. (TAO) is compared with the third target evaporator temperature f3W determined based on the thermal load W, and the higher value is set as a temporary second temporary target evaporator temperature TEO2 ′.

これにより、第２目標蒸発器温度ｆ２（ＴＡＯ）のフロスト熱負荷領域Ｆでの蒸発器目標温度を、第３目標蒸発器温度ｆ３（Ｗ）により、フロストが起きない蒸発器目標温度に高くして仮の第２暫定目標蒸発器温度ＴＥＯ２’とすることができる。 Thereby, the evaporator target temperature in the frost heat load region F of the second target evaporator temperature f2 (TAO) is increased to the evaporator target temperature at which frost does not occur by the third target evaporator temperature f3 (W). Thus, the provisional second provisional target evaporator temperature TEO2 ′ can be obtained.

したがって、制御手段４０が蒸発器温度Ｔｅを第２暫定目標蒸発器温度ＴＥＯ２とするように可変容量圧縮機１９の吐出冷媒流量を制御しても、蒸発器１８にはフロストが発生せず、フロストに起因する可変容量圧縮機１９の停止、つまり空調機能の停止を防止することができる。 Therefore, even if the control means 40 controls the discharge refrigerant flow rate of the variable capacity compressor 19 so that the evaporator temperature Te becomes the second temporary target evaporator temperature TEO2, no frost is generated in the evaporator 18, and the frost is not generated. It is possible to prevent the variable capacity compressor 19 from being stopped, that is, the air conditioning function from being stopped.

また、熱負荷Ｗがフロスト発生熱負荷領域Ｆ内であって、第１暫定目標蒸発器温度ＴＥＯ１がフロスト最大目標蒸発器温度ＴＥＯＨより小さい場合には、第３目標蒸発器温度ｆ３（Ｗ）によりフロストが起きないように算出される第２暫定目標蒸発器温度ＴＥＯ２を蒸発器の目標温度とすることができる。 When the heat load W is within the frost generation heat load region F and the first provisional target evaporator temperature TEO1 is smaller than the frost maximum target evaporator temperature TEOH, the third target evaporator temperature f3 (W) The second provisional target evaporator temperature TEO2 calculated so that frost does not occur can be used as the target temperature of the evaporator.

なお、第１暫定目標蒸発器温度ＴＥＯ１が前記フロスト発生熱負荷領域Ｆにおける最大の蒸発器温度であるフロスト最大目標蒸発器温度ＴＥＯＨ以上の場合には、フロストは発生しないため、蒸発器温度Ｔｅを第１暫定目標蒸発器温度ＴＥＯ１となるように制御すればよい。
（第２実施形態）
第１実施形態では、図７のように検出した熱負荷Ｗに応じた第３目標蒸発器温度ｆ３（Ｗ）を算出した。本実施形態では、まず図９のように最大風量（５００ｍ³／ｈ）時に上限熱負荷Ｗ（ｍａｘ）を発生する湿度１００％空気の温度１８℃（図９のＴｍａｘ）、下限熱負荷Ｗ（ｍｉｎ）を発生する湿度１００％空気の温度１５℃（図９のＴｍｉｎ）を求める。そして、この湿度１００％の空気の温度Ｔｗｅｔを外気温度Ｔａｍとして（Ｔａｍ←Ｔｗｅｔ）、第３目標蒸発器温度ｆ３（Ｔａｍ←Ｔｗｅｔ）を算出している（図１０）。なお、図９中黒丸は本発明者らの実測値である。 When the first provisional target evaporator temperature TEO1 is equal to or higher than the frost maximum target evaporator temperature TEOH that is the maximum evaporator temperature in the frost generation heat load region F, frost is not generated, and therefore the evaporator temperature Te is What is necessary is just to control so that it may become 1st temporary target evaporator temperature TEO1.
(Second Embodiment)
In the first embodiment, the third target evaporator temperature f3 (W) corresponding to the detected thermal load W as shown in FIG. 7 is calculated. In this embodiment, first, as shown in FIG. 9, the temperature of the 100% humidity air that generates the upper limit heat load W (max) at the maximum air volume (500 m ³ / h) is 18 ° C. (Tmax in FIG. 9), and the lower limit heat load W ( min), the temperature of air with 100% humidity and 15 ° C. (Tmin in FIG. 9) is obtained. The third target evaporator temperature f3 (Tam ← Twet) is calculated using the air temperature Twet with 100% humidity as the outside air temperature Tam (Tam ← Twet) (FIG. 10). In FIG. 9, the black circles are measured values obtained by the present inventors.

これによると、エンタルピが一番大きい湿度１００％の空気を外気温度Ｔａｍとして（Ｔａｍ←Ｔｗｅｔ）、第３目標蒸発器温度ｆ３（Ｔａｍ←Ｔｗｅｔ）を算出するため安全側の目標蒸発器温度とすることができる。
（第３実施形態）
第１、第２実施形態では、外部可変容量型圧縮機１９として、容量可変装置１９ｂの制御電流Ｉｎにより図２のように低圧圧力Ｐｓの目標圧力を設定して、低圧圧力Ｐｓがこの目標圧力に維持されるように吐出容量を増減させるもの（低圧圧力制御式）を用いているが、第２実施形態では、外部可変容量型圧縮機１９として、容量可変装置１９ｂの制御電流Ｉｎにより図１１のように圧縮機吐出流量の目標流量Ｇｒｏを設定して、圧縮機吐出流量が目標吐出流量Ｇｒｏに維持されるように吐出容量を増減させるもの（吐出流量制御式）を用いる。 According to this, 100% humidity air with the largest enthalpy is taken as the outside air temperature Tam (Tam ← Twet), and the third target evaporator temperature f3 (Tam ← Twet) is calculated as the safe target evaporator temperature. be able to.
(Third embodiment)
In the first and second embodiments, as the external variable capacity compressor 19, the target pressure of the low pressure Ps is set as shown in FIG. 2 by the control current In of the capacity variable device 19b, and the low pressure Ps is set to the target pressure. However, in the second embodiment, as the external variable capacity compressor 19, the control current In of the variable capacity device 19b is used as the external variable capacity compressor 19 in FIG. In this way, a target flow rate Gro of the compressor discharge flow rate is set, and the discharge capacity is increased or decreased so that the compressor discharge flow rate is maintained at the target discharge flow rate Gro (discharge flow rate control type).

より具体的に説明すると、第２実施形態による吐出流量制御式の外部可変容量型圧縮機１９においては、その吐出側に絞り部を設けており、この絞り部前後に発生する差圧は吐出流量と比例関係にある。従って、この絞り部前後の差圧が目標差圧となるように吐出容量を増減させれば、圧縮機吐出流量が目標吐出流量Ｇｒｏに維持される。 More specifically, in the external variable displacement compressor 19 of the discharge flow rate control type according to the second embodiment, a throttle part is provided on the discharge side, and the differential pressure generated before and after the throttle part is the discharge flow rate. Is proportional to Therefore, if the discharge capacity is increased or decreased so that the differential pressure before and after the throttle becomes the target differential pressure, the compressor discharge flow rate is maintained at the target discharge flow rate Gro.

そこで、容量可変装置１９ｂに、制御電流Ｉｎにより電磁力が決定される電磁機構を設け、この電磁機構により上記目標差圧に相当する電磁力を決定し、この目標差圧に相当する電磁力と絞り部前後の差圧による力との釣り合いにより弁開度を増減する弁機構を容量可変装置１９ｂに備える。 Therefore, the variable capacity device 19b is provided with an electromagnetic mechanism in which the electromagnetic force is determined by the control current In, and the electromagnetic force corresponding to the target differential pressure is determined by the electromagnetic mechanism, and the electromagnetic force corresponding to the target differential pressure and The variable capacity device 19b is provided with a valve mechanism for increasing or decreasing the valve opening degree by balancing with the force due to the differential pressure before and after the throttle portion.

この弁機構の弁開度の増減により斜板室の圧力を制御することにより、斜板の傾斜角度を可変して圧縮機吐出容量を略０％〜１００％の範囲で連続的に変化させることができる。このような吐出流量制御式の外部可変容量型圧縮機１９を用いても第１実施形態と同様の作用効果を発揮できる。なお、吐出流量制御式の外部可変容量型圧縮機１９は特開２００１−１０７８５４号公報等により公知である。 By controlling the pressure in the swash plate chamber by increasing or decreasing the valve opening of the valve mechanism, the inclination angle of the swash plate can be varied to continuously change the compressor discharge capacity in the range of approximately 0% to 100%. it can. Even if such a discharge flow rate control type external variable capacity compressor 19 is used, the same effects as those of the first embodiment can be exhibited. Note that a discharge flow rate control type external variable capacity compressor 19 is known from Japanese Patent Application Laid-Open No. 2001-107854.

（第４実施形態）
第１〜第３実施形態では、いずれも、圧縮機として吐出容量を変更可能な外部可変容量型圧縮機１９を用い、吐出容量の変更により吐出流量を変更する場合について説明したが、第４実施形態では図１２に示すように圧縮機として電動圧縮機１９を用いている。この電動圧縮機１９は、モータ１９ｃとこのモータ１９ｃにより駆動される圧縮機構部１９ｄとを一体化したものである。モータ１９ｃは具体的には３相交流モータであり、また、圧縮機構部１９ｄは周知のスクロール式圧縮機構である。 (Fourth embodiment)
In each of the first to third embodiments, the external variable capacity compressor 19 that can change the discharge capacity is used as the compressor, and the discharge flow rate is changed by changing the discharge capacity. In the embodiment, an electric compressor 19 is used as a compressor as shown in FIG. The electric compressor 19 is obtained by integrating a motor 19c and a compression mechanism 19d driven by the motor 19c. The motor 19c is specifically a three-phase AC motor, and the compression mechanism 19d is a well-known scroll type compression mechanism.

モータ１９ｃに付与される３相交流電源の周波数をインバータ１９ｅにより可変制御することによりモータ回転数を制御し、モータ回転数の高低に応じて電動圧縮機１９の冷媒吐出流量を増減できる。インバータ１９ｅは空調用制御装置４０の制御出力により制御される。 The motor rotation speed is controlled by variably controlling the frequency of the three-phase AC power applied to the motor 19c by the inverter 19e, and the refrigerant discharge flow rate of the electric compressor 19 can be increased or decreased according to the motor rotation speed. The inverter 19e is controlled by the control output of the air conditioning controller 40.

この第４実施形態にでは蒸発器吹出温度（蒸発器温度）Ｔｅが最終目標蒸発器温度ＴＥＯとなるように、電動圧縮機１９の回転数（すなわち、電動圧縮機１９の冷媒吐出流量）を制御することにより、蒸発器温度Ｔｅを確実に最終目標蒸発器温度ＴＥＯに制御できる。 In the fourth embodiment, the rotational speed of the electric compressor 19 (that is, the refrigerant discharge flow rate of the electric compressor 19) is controlled so that the evaporator outlet temperature (evaporator temperature) Te becomes the final target evaporator temperature TEO. By doing so, the evaporator temperature Te can be reliably controlled to the final target evaporator temperature TEO.

第４実施形態においても、第１〜第３実施形態と同様に蒸発器温度Ｔｅが最終目標蒸発器温度ＴＥＯとなるように空調ＥＣＵ４０が電動圧縮機１９の吐出冷媒流量を制御しても、蒸発器１８にはフロストが発生せず、フロストに起因する圧縮機１９の停止、つまり空調機能の停止を防止することができる。 Also in the fourth embodiment, even if the air conditioning ECU 40 controls the discharge refrigerant flow rate of the electric compressor 19 so that the evaporator temperature Te becomes the final target evaporator temperature TEO as in the first to third embodiments, the evaporation is performed. The frost is not generated in the compressor 18, and the stop of the compressor 19, that is, the stop of the air conditioning function due to the frost can be prevented.

このように、圧縮機として外部可変容量型圧縮機１９の代わりに電動圧縮機１９を用いても、第１〜第３実施形態と同様の作用効果を発揮できる。 Thus, even if the electric compressor 19 is used instead of the external variable capacity compressor 19 as a compressor, the same effects as those of the first to third embodiments can be exhibited.

（他の実施形態）
上述の第１実施形態で述べた図８の第３目標蒸発器温度の特性図の決定は、ある形状の蒸発器１８、ＨＦＣ−１３４ａ、蒸発器１８への最大風量（５００ｍ³／ｈ）などのパラメータ値を有する場合の一例として、第３目標蒸発器温度の特性図の決定過程を示したものである。当然に蒸発器１８の形状、冷媒の種類、蒸発器１８への風量が変化しても、同様の手順により図７のような特性図を求めることができる。 (Other embodiments)
The determination of the characteristic graph of the third target evaporator temperature of FIG. 8 described in the first embodiment described above is based on the evaporator 18 having a certain shape, the HFC-134a, the maximum air flow (500 m ³ / h) to the evaporator 18, and the like. As an example of the case of having the parameter values, the process of determining the characteristic diagram of the third target evaporator temperature is shown. Naturally, even if the shape of the evaporator 18, the type of refrigerant, and the amount of air flow to the evaporator 18 change, a characteristic diagram as shown in FIG. 7 can be obtained by the same procedure.

また、第１〜第４実施形態では、冷媒としてＨＦＣ−１３４ａを使用した例を示したが、本発明はＲ−１２など他の冷媒を使用した凝縮サイクルや、冷媒に例えば二酸化炭素（ＣＯ２）を使用した超臨界冷凍サイクルにも適用可能である。 Moreover, although the example which used HFC-134a as a refrigerant | coolant was shown in 1st-4th embodiment, this invention is a condensation cycle using other refrigerant | coolants, such as R-12, and a carbon dioxide (CO2) is used for a refrigerant | coolant, for example. It can also be applied to a supercritical refrigeration cycle using

また、第１〜第３実施形態では、第２目標蒸発器温度（ｆ２（ＴＡＯ））と第３目標蒸発器温度（ｆ３（Ｗ））とを比較して、高い方の値を仮の第２暫定目標蒸発器温度（ＴＥＯ２’）とし、その後仮の第２暫定目標蒸発器温度（ＴＥＯ２’）と第１目標蒸発器温度（ｆ１（Ｔａｍ））とを比較して低い方の値を第２暫定目標蒸発器温度（ＴＥＯ２）とする例を示した。 In the first to third embodiments, the second target evaporator temperature (f2 (TAO)) is compared with the third target evaporator temperature (f3 (W)), and the higher value is set as a temporary first value. 2 provisional target evaporator temperature (TEO2 ′), and then the provisional second provisional target evaporator temperature (TEO2 ′) is compared with the first target evaporator temperature (f1 (Tam)) to determine the lower value. 2 shows an example in which the provisional target evaporator temperature (TEO2) is used.

しかし、第１目標蒸発器温度ｆ１（Ｔａｍ）が目的とする防曇効果によっては、第３目標蒸発器温度ｆ３（Ｗ）、ｆ３（Ｔａｍ←Ｔｗｅｔ）でフロストを回避した蒸発器目標温度が、第１目標蒸発器温度ｆ１（Ｔａｍ）によりフロストする第２暫定目標蒸発器温度ＴＥＯ２となる場合がある。そのため、第３目標蒸発器温度ｆ３（Ｗ）が第２目標蒸発器温度ｆ２（ＴＡＯ）よりも高い値の場合には、第３目標蒸発器温度ｆ３（Ｗ）の値が第１目標蒸発器温度ｆ１（Ｔａｍ）に関わらず第２暫定目標蒸発器温度ＴＥＯ２となるようにしてもよい。 However, depending on the anti-fogging effect intended by the first target evaporator temperature f1 (Tam), the evaporator target temperature that avoids frost at the third target evaporator temperature f3 (W), f3 (Tam ← Twet), There is a case where the second temporary target evaporator temperature TEO2 is frosted by the first target evaporator temperature f1 (Tam). Therefore, when the third target evaporator temperature f3 (W) is higher than the second target evaporator temperature f2 (TAO), the value of the third target evaporator temperature f3 (W) is the first target evaporator. You may make it become 2nd temporary target evaporator temperature TEO2 irrespective of temperature f1 (Tam).

本発明の第１実施形態を示す車両用空調装置の概要システム構成図である。It is a general | schematic system block diagram of the vehicle air conditioner which shows 1st Embodiment of this invention. 第１実施形態に用いる可変容量型圧縮機の制御特性図である。It is a control characteristic figure of the variable capacity type compressor used for a 1st embodiment. 第１実施形態における電気制御部の概略ブロック図である。It is a schematic block diagram of the electric control part in 1st Embodiment. 第１実施形態による容量制御全体の概略フローチャートである。It is a schematic flowchart of the whole capacity | capacitance control by 1st Embodiment. 図４のＴＥＯ算出ステップＳ１２０の具体的フローチャートである。It is a specific flowchart of TEO calculation step S120 of FIG. 図５のＳ１２６０の作動説明に供する第１、第２目標蒸発器温度の特性図である。It is a characteristic view of the 1st, 2nd target evaporator temperature with which it uses for operation | movement description of S1260 of FIG. 図５のＳ１２７０の作動説明に供する第２、第３目標蒸発器温度の特性図である。It is a characteristic view of the 2nd, 3rd target evaporator temperature with which it uses for operation | movement description of S1270 of FIG. 図８の第３目標蒸発器温度の特性図決定の過程を示す図であり、蒸発器への熱負荷と冷凍サイクルの低圧圧力との関係を示す図である。It is a figure which shows the process of the characteristic view determination of the 3rd target evaporator temperature of FIG. 8, and is a figure which shows the relationship between the thermal load to an evaporator, and the low pressure of a refrigerating cycle. 最大風量（５００ｍ³／ｈ）の湿度１００％空気の温度と蒸発器への熱負荷との関係を示す図である。It is a figure which shows the relationship between the temperature of the humidity 100% air of the maximum air volume (500m < ³ > / h), and the heat load to an evaporator. 第２実施形態の湿度１００％空気の温度に基づく第３目標蒸発器温度と、第２目標蒸発器温度の特性図である。It is a characteristic figure of the 3rd target evaporator temperature based on the temperature of 100% humidity air of the 2nd embodiment, and the 2nd target evaporator temperature. 第３実施形態による可変容量型圧縮機の制御特性図である。It is a control characteristic figure of the variable capacity type compressor by a 3rd embodiment. 第４実施形態による電動圧縮機の制御ブロック図である。It is a control block diagram of the electric compressor by 4th Embodiment.

Explanation of symbols

１１…ケース、１７…送風機、１８…蒸発器、１９…可変容量圧縮機、
４０…制御手段（空調ＥＣＵ）、４１ａ…蒸発器温度検出手段（蒸発器温度センサ）、
４１ｂ…流入空気湿度検出手段（吸込空気温度センサ）、
４１ｃ…外気温度検出手段（外気温センサ）、
４１ｄ…流入空器温度検出手段（内気温センサ）、
Ｔａｍ…外気温、Ｔｒ…内気温、ＲＨ…吸込空気の湿度、Ｔｅ…蒸発器温度、
ＴＡＯ…目標吹出温度、ＴＥＯ１…第１暫定目標蒸発器温度、
ＴＥＯ２’…仮の第２暫定目標蒸発器温度、ＴＥＯ２…第２暫定目標蒸発器温度、
ＴＥＯＨ…フロスト最大目標蒸発器温度、ｆ１（Ｔａｍ）…第１目標蒸発器温度、
ｆ２（ＴＡＯ）…第２目標蒸発器温度、ｆ３（Ｗ）…第３目標蒸発器温度、
Ｆ…フロスト熱負荷領域、Ｉｎ…制御信号、Ｗ…蒸発器の熱負荷。

11 ... Case, 17 ... Blower, 18 ... Evaporator, 19 ... Variable capacity compressor,
40 ... control means (air conditioning ECU), 41a ... evaporator temperature detection means (evaporator temperature sensor),
41b ... Inflow air humidity detection means (suction air temperature sensor),
41c: outside air temperature detecting means (outside air temperature sensor),
41d ... Inflow air temperature detection means (inside air temperature sensor),
Tam ... outside temperature, Tr ... inside temperature, RH ... intake air humidity, Te ... evaporator temperature,
TAO ... target blowing temperature, TEO1 ... first provisional target evaporator temperature,
TEO2 '... Temporary second provisional target evaporator temperature, TEO2 ... Second provisional target evaporator temperature,
TEOH: Frost maximum target evaporator temperature, f1 (Tam): First target evaporator temperature,
f2 (TAO): second target evaporator temperature, f3 (W): third target evaporator temperature,
F: Frost heat load region, In: control signal, W: heat load of the evaporator.

Claims

A case (11) that forms a passage for air flowing into the air-conditioned space;
A blower (17) disposed in the case (11) and creating an air flow to the air-conditioned space;
A variable capacity compressor (19) configured to control the discharge refrigerant flow rate by an external control signal (In);
An evaporator (18) connected to the suction side of the compressor (19), which absorbs heat from the air flowing into the air-conditioned space and evaporates low-pressure refrigerant;
Control means (40) for controlling the flow rate of refrigerant discharged from the variable capacity compressor (19),
The control means (40) calculates the heat load (W) of the air flowing into the evaporator (18), and further the heat load region (F) where the frost given the heat load (W) is generated. Determine whether it is inside or outside,
When the heat load (W) is outside the frost generation heat load region (F), the discharge refrigerant flow rate of the variable capacity compressor (19) is controlled based on the heat load in the air conditioning target space,
When the heat load (W) is within the frost generation heat load region (F), the discharge refrigerant flow rate of the variable capacity compressor (19) is calculated based on the heat load in the space to be air-conditioned. A refrigeration cycle apparatus that is controlled to a flow rate smaller than a refrigerant flow rate.

A case (11) that forms a passage for air flowing into the air-conditioned space;
A blower (17) disposed in the case (11) and creating an air flow to the air-conditioned space;
An evaporator (18) disposed in the case (11), which absorbs heat from the air flowing into the air-conditioning target space and evaporates the low-pressure refrigerant;
A variable capacity compressor (19) connected to the refrigerant flow downstream side of the evaporator (18) and configured to control the discharge refrigerant flow rate by changing the discharge capacity by an external control signal (In); ,
Evaporator temperature detecting means (41a) for detecting the temperature of the evaporator (18);
An outside air temperature detecting means (41c) for detecting an air temperature outside the air conditioning target space;
Control means (40) for receiving detection signals of the evaporator temperature detection means (41a) and the outside air temperature detection means (41c) and outputting the control signal (In) to the variable capacity compressor (19). Prepared,
The control means (40) includes at least a first target evaporator temperature (f1 (Tam)) determined by a detected temperature (Tam) of the outside air temperature detection means (41c) and a target of air blown out to the air-conditioning target space. A first provisional target evaporator temperature (TEO1) is calculated based on the second target evaporator temperature (f2 (TAO)) determined by the blowing temperature (TAO),
Further, the control means (40) includes a heat load (W) of air flowing into the evaporator (18), and a third target evaporator temperature (f3 (W)) determined by the heat load (W). To calculate
The control means (40) is provided with a heat load region (F) where frost is generated in advance,
When the heat load (W) is outside the frost generation heat load region (F), the control means (40) has the evaporator temperature (Te) detected by the evaporator temperature detection means (41a) as the first temperature. 1 to output the control signal (In) so as to be the temporary target evaporator temperature (TEO1),
When the heat load (W) is within the frost generation heat load region (F), the control means (40) at least the second target evaporator temperature (f2 (TAO)) and the third target evaporator. Comparing with the temperature (f3 (W)), the higher value is set as the temporary second temporary target evaporator temperature (TEO2 ′),
Further, the control means (40) is configured to determine the second provisional target evaporator temperature based on at least the provisional second provisional target evaporator temperature (TEO2 ′) and the detected temperature (Tam) of the outside air temperature detection means (41c). (TEO2) is calculated,
The refrigeration cycle apparatus, wherein the control signal (In) is output so that the evaporator temperature (Te) becomes the second provisional target evaporator temperature (TEO2).

The control means (40) is provided with a frost maximum target evaporator temperature (TEOH) which is a maximum evaporator temperature in the frost generation heat load region (F),
The control means (40) is configured such that the thermal load (W) is within the frost generation thermal load region (F), and the first temporary target evaporator temperature (TEO1) is the frost maximum target evaporator temperature (TEOH). In the above case, the control signal (In) is output so that the evaporator temperature (Te) detected by the evaporator temperature detecting means (41a) becomes the first provisional target evaporator temperature (TEO1). ,
On the other hand, when the heat load (W) is within the frost generation heat load region (F) and the first provisional target evaporator temperature (TEO1) is lower than the frost maximum target evaporator temperature (TEOH). The control signal (In) is output so that the evaporator temperature (Te) detected by the evaporator temperature detecting means (41a) becomes the second temporary target evaporator temperature (TEO2). The refrigeration cycle apparatus according to claim 2.

Inflow air temperature detection means (41c, 41d) for detecting the temperature of the air flowing into the evaporator (18);
Inflow air humidity detection means (41b) for detecting the humidity of the air flowing into the evaporator (18),
Detection signals of the inflow air temperature detection means (41c, 41d) and the inflow air humidity detection means (41b) are input to the control means (40),
The control means (40) includes at least detection temperatures (Tam, Tr) of the inflow air temperature detection means (41c, 41d), detection humidity (RH) of the inflow air humidity detection means (41b), and the blower (17). The refrigeration cycle apparatus according to claim 2 or 3, wherein the thermal load (W) is calculated based on the amount of air blown.