JP2005212543A - Compressor control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compressor control device capable of improving running fuel economy by optimally controlling compressor torque according to the load condition of an engine in normal running. <P>SOLUTION: The compressor control device is equipped with a variable displacement compressor, an engine speed detection means, a torque target value reference means referring the engine output torque target value calculated by an accelerator depressing amount detection means or an engine ECU, and an engine output estimation means estimating the present engine output torque from at least the accelerator depressing amount or the engine output torque target value and the engine speed. The compressor control device determines a compressor torque limit value from the engine output torque and the engine speed by using a torque limit value map of the map defining the compressor torque limit value especially on the two-axis plane of the engine output torque and the engine speed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a compressor control device used in a vehicle air conditioner, and more particularly, to a compressor control device that optimally controls a compressor according to the load state of an engine to improve traveling fuel consumption.

2. Description of the Related Art Conventionally, a technique for improving the acceleration performance and fuel consumption of a vehicle by reducing the capacity of an air conditioner compressor during vehicle acceleration is known (for example, Patent Document 1). In addition, control is performed to improve fuel efficiency by calculating the lean limit torque in the lean combustion region of an engine with good fuel efficiency and controlling each device for air conditioners including the compressor in consideration of the margin. Is also known (for example, Patent Document 2).
JP-A-1-175518 JP 2003-127654 A

  However, in the prior art as described above, the compressor is controlled to a predetermined level only when accelerating or when the engine is in a certain state, so that the fuel consumption is improved. It is not possible to perform control in consideration of all engine load conditions including For this reason, the compressor is not always optimally controlled to improve fuel efficiency, and there is still room for improvement.

  Therefore, an object of the present invention is to provide a compressor control device capable of optimally controlling the compressor torque according to the load state of the engine and improving the traveling fuel consumption not only during acceleration but also during normal traveling. It is to provide.

  In order to solve the above problems, a compressor control device according to the present invention detects a variable displacement compressor capable of changing a discharge capacity, an engine speed detecting means for detecting an engine speed, and an accelerator depression amount. Accelerator depression amount detection means or torque target value reference means for referring to the engine output torque target value calculated by the engine ECU, and at least the current engine output torque is estimated from the accelerator depression amount or engine output torque target value and the engine speed. An engine output estimating means for determining a compressor torque limit value with reference to the estimated engine output torque and the engine speed.

  Further, the compressor control device according to the present invention includes a variable capacity compressor capable of changing a discharge capacity, an engine speed detecting means for detecting an engine speed, and an accelerator depression amount detecting means for detecting an accelerator depression amount, or Torque target value reference means for referring to the engine output torque target value calculated by the engine ECU, engine output estimation means for estimating the current engine output torque from at least the accelerator depression amount or the engine output torque target value and the engine speed, A torque limit value map that is a map that defines a compressor torque limit value in a biaxial plane of the engine output torque and the engine speed, and the compressor torque is calculated from the engine output torque and the engine speed using the torque limit value map. It is characterized by determining a limit value.

  In such a compressor control device according to the present invention, the compressor control device further includes torque estimating means for estimating the compressor torque, and the compressor torque estimated value estimated by the torque estimating means is equal to or less than the compressor torque limit value. Thus, the torque of the compressor can be controlled.

  When the compressor torque limit value is a specific set value (for example, a negative value or a value larger than the maximum torque value), the compressor torque can be forcibly increased.

  The compressor control device according to the present invention further includes a thermal load detecting means for detecting a thermal load on the refrigeration cycle, and when the thermal load is equal to or higher than a predetermined value, the compressor torque is limited. Can be avoided.

  Such a compressor control device according to the present invention can be configured as an independent control device, or can be incorporated in an engine ECU.

  As the torque limit value map, a map obtained by an experiment conducted in advance can be used. As this torque limit value map, a map having a plurality of regions in which different compressor torque limit values are defined can be created as shown in an embodiment described later. Further, this torque limit value map can be created as a map having a torque limit value region of a jump region on the map.

  The present invention focuses on the fact that the difference in air-fuel ratio between when the compressor is on and when it is off corresponds to the combustion region of the engine, as will be described in detail in the following theoretical explanation. A map representing the region of the air-fuel ratio difference on the biaxial plane of the output torque and the engine speed is created as a torque limit value map, and the torque of the compressor is controlled based on this torque limit value map. Therefore, the optimum compressor control according to the actual engine state including the normal running state is possible, and the most efficient control state can be realized particularly from the viewpoint of improving the fuel consumption.

  According to the compressor control device of the present invention, the compressor torque control based on the compressor torque limit value determined with reference to the estimated engine output torque and the engine speed, in particular, the engine output torque and the engine speed. The new torque control method based on the compressor torque limit map based on the number of biaxial planes has been adopted so far. This makes it possible to perform optimal compressor control in accordance with the state of the engine, and to improve the fuel efficiency of the vehicle with high efficiency.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
First, the theoretical basis that the compressor control device according to the present invention is useful for improving fuel efficiency will be described. The present invention is particularly suitable for a system in which a direct injection gasoline engine is used as a drive source of a compressor. In a direct injection gasoline engine, the combustion state (stratified combustion and homogeneous combustion) is switched depending on the traveling load. In stratified combustion, there is little intake loss and heat loss in the cylinder, and efficiency is high. Therefore, it is selected when the traveling load is low. On the other hand, homogeneous combustion is selected when the traveling load is high. Actually, the combustion state is switched as shown in FIG. 1 with respect to the engine output torque Te and the engine speed Ne. If the compressor torque limit control according to the present invention is performed on an engine that changes the air-fuel ratio, such as this direct injection gasoline engine, the fuel consumption can be reduced. The factors will be described below.

  As shown in FIG. 2, in the direct injection gasoline engine, in the two-dimensional map of the engine output torque Te and the engine speed Ne, a region where a large difference in air-fuel ratio occurs between when the compressor is turned on and when it is turned off, There are areas that hardly make a difference. However, the stratified combustion region is limited here. In the homogeneous combustion region, the air-fuel ratio is constant even if the compressor torque changes. FIG. 2 shows the air-fuel ratio difference when the compressor is on and off with respect to the engine output torque Te and the engine speed Ne when the compressor is off. Basically, when the compressor is turned on, the air-fuel ratio becomes smaller than when the compressor is turned off. The smaller the air-fuel ratio, the lower the efficiency of the engine, and the worse the fuel efficiency.

  Therefore, in a region where the air-fuel ratio difference is large, for example, as shown in FIG. 3, a large fuel efficiency improvement effect can be obtained by limiting the compressor torque and reducing the amount of air-fuel ratio drop. Conversely, in a region where the air-fuel ratio difference is small, the compressor torque is positively (forcedly) increased to lower the evaporator temperature. In this region, the increase in fuel consumption is small. Therefore, if the evaporator temperature is lowered and stored in this region, the cooling capacity can be ensured even if the torque is reduced when the driving condition changes and shifts to a region where the air-fuel ratio difference is large. Become.

  One region where the air-fuel ratio difference is large is a region near the boundary between stratified combustion and homogeneous combustion. This is because the engine output torque Te is increased by turning on the compressor, the combustion state is switched from stratified combustion to homogeneous combustion, and the air-fuel ratio is greatly reduced. In the same stratified combustion region, there are a region with a large air-fuel ratio difference and a region with a small air-fuel ratio as shown in the figure. If these regions are obtained in advance by experiments, a map (two-dimensional map) is created on the biaxial plane of the engine output torque Te and the engine speed Ne, and the compressor torque is limited and controlled along the map, the engine Therefore, it is possible to perform optimal control according to the state of the engine and improve fuel efficiency.

The engine output torque Te is obtained, for example, as follows.
As shown in FIG. 4, first, the accelerator opening Acc is adjusted by the passenger. Further, the current compressor torque Tc is calculated in the engine ECU or the air conditioning control device. Then, an engine output torque target value Set is calculated from the accelerator opening Acc and the compressor torque Tc. Further, the correction value Tset ′ of the engine output torque target value is calculated from the air-fuel ratio AFR and the EGR (exhaust gas recirculation) rate in the engine. This is done to prevent Te, which is the actual engine output torque, from changing due to changes in the air-fuel ratio AFR and the EGR rate. Therefore, the engine output torque Te at a certain running load and a certain gear ratio is set to the same value regardless of the values of the air-fuel ratio AFR and the EGR rate with respect to a correction value Tset ′ of a certain engine output torque target value Tset. Can do. The throttle opening degree Th is determined by the correction value Tset ′ of the engine output torque target value. For a certain throttle opening Th, the engine output torque Te and the engine speed Ne change as shown in FIG. 4 depending on the travel load (large, medium, small) and the gear ratio. That is, if the accelerator opening Acc is the same, the engine output torque Te and the engine speed Ne are determined by the traveling load (however, the throttle opening Th is different).

The engine output torque Te is estimated as follows, for example.
Based on the factors of the engine output torque Te, the method for estimating the engine output torque Te is as follows. First, since the engine output torque target value Set is corrected by the air-fuel ratio AFR and the EGR rate, the engine output torque Te can be estimated without using the air-fuel ratio AFR and the EGR rate values. Therefore, the accelerator opening Acc, the engine speed Ne, and the compressor torque Tc are the main factors that determine the value of the engine output torque Te.

  That is, for a certain accelerator opening degree Acc, the throttle opening degree Th differs depending on the air-fuel ratio AFR and the EGR rate, but the engine output torque Te at a certain traveling load is the same. Further, when the traveling load changes with respect to a certain accelerator opening Acc, both the engine output torque Te and the engine speed Ne change. Therefore, as shown in FIG. 6 to be described later, the engine output torque Te can be calculated from the characteristic diagram of the engine output torque Te, the engine speed Ne, and the accelerator opening Acc. Further, as shown in FIG. 7, which will be described later, the engine output torque Te can be calculated from the engine output torque target value Teset, the engine rotation speed Ne, and the engine output torque Te characteristic diagram.

  Further, the estimation of the engine output torque Te based on the accelerator opening Acc and the engine speed Ne does not include the engine output torque increase amount for driving the compressor. This is because the engine ECU automatically adds the engine output torque for driving the compressor to the engine output torque target value Setet determined by the accelerator opening Acc.

  Since the torque limit map used in the present invention is a map corresponding to the engine output torque Te when the compressor is off and the engine speed Ne, the engine output torque Te not including the increase in output torque for driving the compressor is calculated. Referring to, compressor torque limit value Tcmax is determined. Therefore, the compressor output torque limit value Tcmax can be calculated from the torque limit value map by using the engine output torque Te obtained from the accelerator opening Acc and the engine speed Ne as described above.

  As described above, according to the present invention, in a direct injection gasoline engine capable of changing the air-fuel ratio, in a region where the air-fuel ratio change due to on / off of the compressor is large, the compressor torque is suppressed as small as possible. In a region where the change in air-fuel ratio due to on / off is small, the torque of the compressor is forcibly increased, so that the vehicle can be run with high engine efficiency, and fuel efficiency can be improved.

  More specifically, for example, the following control is performed in the compressor control device according to the present invention based on the above theory. First, FIG. 5 shows a configuration example of a refrigeration cycle in a vehicle air conditioner to which a compressor control device according to the present invention is applied. The refrigeration cycle 1 is provided with a refrigerant compressor 2, a condenser 3, a receiver (receiver dryer) 4, an expansion valve 5, and an evaporator 6 as a cooler. For air conditioning control, a detection signal 7 is input from a high-pressure sensor, a solar radiation sensor, an indoor temperature sensor, an outside air temperature sensor, an evaporator temperature sensor, etc., for detecting the high-pressure side pressure of the refrigerant circuit. It is controlled by a capacity control signal 9 from the air conditioning control device 8. A blower 11 is disposed on the upstream side of the evaporator 6 in the ventilation duct 10, a heater 12 is disposed on the downstream side, and an air mix damper 13 is disposed on the upstream side of the heater 12.

  FIG. 6 (refer to accelerator opening Acc and engine speed Ne) and FIG. 7 (refer to engine output torque target value Setet and engine speed Ne) are shown in FIG. 6 (example of control flow in the compressor control device according to the present invention). Shown in As the torque limit value map, a map obtained by experiments in advance as shown in FIG. 3 is used.

  As described above, in the control flow shown in FIG. 6, the engine output torque Te is obtained according to the travel load from the characteristic graph of the accelerator opening Acc, the engine speed Ne, and the engine output torque Te. A compressor torque limit value Tcmax is calculated from a two-dimensional map of the torque Te and the engine speed Ne. In the control flow shown in FIG. 7, the engine output torque Te is obtained according to the traveling load from the characteristic graph of the engine output torque target value Teset, the engine speed Ne, and the engine output torque Te, and the obtained engine output torque Te A compressor torque limit value Tcmax is calculated from a two-dimensional map of the engine speed Ne.

A specific example of the calculation of the compressor torque limit value Tcmax using the torque limit value map as shown in FIG. 3 will be described below.
Example 1
The torque limit value map is, for example, a torque limit value determined on the xy plane, but in actual software, the torque limit value is determined by a two-dimensional array (for example, T [x] [y]), When the values of x and y are determined, a corresponding array is referred to and a torque limit value is determined.

The conceptual diagram is illustrated in FIG. A torque limit value (value A, value B,..., Value G) is set for each region divided by the boundary line, and the set torque limit value is stored in each array. As a setting method to each array of torque limit value,
・ Method to set torque limit value for each array one by one,
A method of creating a torque limit value map as image data having the torque limit value as luminance data or color data, and reading this image data into each array;
Etc.

Example 2
As shown in FIG. 9, in the torque limit value map on the xy plane, the boundary line of the region where the limit value is the same is functionalized. Here, let each function be f1, f2, f3,... Fn. The torque limit value is set to a value between adjacent boundary lines. For example, when there is no other boundary line between f1 and f2, this is adjacent to each other, and f1 and f2 In the meantime, a certain torque limit value is set. In addition, torque limit values are set for all adjacent boundary lines and boundary lines. Also, when a certain region is a region closed by one function, a torque limit value is set between the same function.

  Here, the torque limit value when (x = a, y = b) can be obtained as follows. First, by calculating f1 (a), f2 (a), f3 (a)... Fn (a), the y-coordinate of each boundary line at the x-coordinate a is obtained. The calculated y coordinate of each boundary line is compared with b, and the two y coordinates k and m closest to b are obtained (where k ≦ b and b <m). A torque limit value set between the functions corresponding to k and m is determined as a torque limit value at (x = a, y = b).

In the above description, the thermal load is determined as follows, for example. The air-conditioning control device 8 detects the value of each sensor, and determines that the thermal load is large and does not perform compressor torque limit control when at least one of the following thermal load conditions is satisfied.
-Indoor temperature sensor detection amount: Tr
・ Target room temperature: Trset
・ Outside temperature: Tam
・ Solar radiation: R
・ Evaporator temperature: Teva
・ Evaporator temperature target value: Tevaset
If
If at least one of the following (1) to (6) is satisfied, it is determined that the heat load is large, and the compressor torque limit control is not performed.
(1) Tr-Trset> N1
(2) Trset <N2
(3) R> N3
(4) Teva− Tevaset> N4
(5) Teva> N5
(6) Tam> N6
Here, N1 to N6 are predetermined constants.

  Further, the compressor torque Tc is estimated as follows, for example. In order to control the compressor torque Tc with the compressor torque limit value Tcmax, the compressor torque Tc is estimated, and the compressor torque Tc is adjusted so that the compressor torque Tc is equal to or less than the compressor torque limit value Tcmax. The compressor torque Tc is adjusted by changing the current supplied to the capacity control valve of the compressor by a duty signal or the like. Here, the compressor torque Tc is estimated by the following method.

<Compressor torque estimation method (1)>
The pressure difference between the discharge pressure Pd and the suction pressure Ps of the compressor is detected, and the compressor torque Tc is calculated from the pressure difference. The compressor torque can be calculated by the following equation.
Tc = a * (Pd − Ps) + c
Here, a, c are constants obtained by experiments, and here, the discharge pressure Pd uses the amount detected by the pressure sensor. The suction pressure Ps may be detected by a pressure sensor, or may be estimated from the air temperature after passing through the evaporator.

<Compressor torque estimation method (2)>
When a variable capacity compressor capable of controlling the pressure difference between the discharge pressure Pd and the suction pressure Ps is used, the compressor torque Tc is directly calculated from the capacity control signal in order to control the pressure difference between the discharge pressure Pd and the suction pressure Ps. It is possible. The compressor torque Tc can be calculated by the following equation.
Tc = a * EMPCV + c
Here, EMPCV: compressor capacity control signal a, c: constants obtained by experiments.
Furthermore, accuracy can be increased by referring to the engine speed Ne.
Tc = a * EMPCV + b * Ne + c
Here, a, b, c are constants obtained by experiments.

<Compressor torque estimation method (3)>
First, the compressor torque Tc can be calculated from the following equation.
The compressor torque Tc can be calculated by the following equation.
Tc = k · Ps {(Pd / Ps) ^m −1} Vc
Here, k and m are constants, and Vc is a compressor discharge amount [cc].
The compressor discharge amount Vc can be calculated by the following equation.
Vc = Gr / (Nc ・ F)
Here, Gr: refrigerant flow rate [kg / h], Nc: compressor rotation speed [rpm], and F: volume weight [kg / cm ³ ].
Further, since the volume weight F is highly correlated with the suction pressure Ps, the compressor torque Tc can be calculated by the following equation.
Tc = k · Ps {(Pd / Ps) ^m −1} Gr / (Nc · Ps · t) (1)
Here, t is a constant.
Therefore, in order to calculate the compressor torque Tc, it is necessary to detect or estimate the discharge pressure Pd, the suction pressure Ps, the refrigerant flow rate Gr, and the compressor rotation speed Nc. In the following (1) to (4), the detection or estimation method of each value is described.

(1) Method for Estimating Refrigerant Flow Rate Gr Refrigerant-side cooling capacity (hereinafter referred to as evaporator cooling capacity) Qer in an evaporator is a refrigerant specific enthalpy difference (hereinafter referred to as an evaporator inlet / outlet specific enthalpy difference) ΔIe and refrigerant. It is represented by the product of the flow rate Gr.
Qer = ΔIe * Gr
Therefore, if the specific enthalpy difference ΔIe at the evaporator inlet / outlet and the evaporator cooling capacity Qer can be estimated, the refrigerant flow rate Gr can be estimated. Hereinafter, the specific enthalpy difference ΔIe at the evaporator inlet / outlet and the evaporator cooling capacity Qer are estimated from (a) and (b).

(A) From the estimated Mollier diagram of the specific enthalpy difference ΔIe at the inlet / outlet of the evaporator, the specific enthalpy difference ΔIe at the inlet / outlet of the evaporator is greatly influenced by ΔPdPs, which is the difference between the discharge pressure Pd and the suction pressure Ps.
That is, as ΔPdPs increases, the specific enthalpy difference ΔIe at the evaporator inlet / outlet decreases.
As a result of analyzing the experimental data, it was found that the specific enthalpy difference ΔIe at the entrance and exit of the evaporator can be estimated with high accuracy by the following equation.
ΔIe = a * ΔPdPs + m
Where a, b, m are constants derived from experiments.
Alternatively, it can be estimated by the following equation.
ΔIe = a * Pd + b * Ps + m
Where a, b, m are constants derived from experiments.

In addition, in an air conditioner using a subcool condenser capable of supercooling the refrigerant as a condenser, the specific enthalpy difference ΔIe at the evaporator inlet / outlet varies greatly depending on the value of the degree of supercooling, so the refrigerant temperature Ttxv-r before the decompression mechanism It is possible to estimate the specific enthalpy difference ΔIe at the evaporator inlet / outlet in consideration of the value of the degree of supercooling.
ΔIe = a * Ttxv-r + b * Teo + m
Here, Teo: air temperature immediately after passing through the evaporator, a, b, m: constants derived by experiments.
Alternatively, it can be estimated by the following equation.
ΔIe = a * Ttxv-r + b * Pd + c * Ps + m
Here, a, b, m are constants derived by experiments.

(B) Estimated Evaporator Cooling Capacity Qer The estimated evaporator cooling capacity Qer is correlated to the air volume passing through the evaporator or a physical quantity BLV correlated therewith, the air temperature Tei before passing through the evaporator, and the air temperature Teo immediately after passing through the evaporator. The evaporator cooling capacity Qer can be estimated by the following equation.
Qer = k * BLV * (Tei-Teo) + m
Here, k and m are constants. Further, as the air volume passing through the evaporator or the physical quantity BLV correlated therewith, it is preferable to use an applied voltage or an input current to a blower motor (blower driving motor).
Furthermore, the evaporator cooling capacity Qer can be estimated with high accuracy by referring to ΔPdPs. Therefore, the evaporator cooling capacity Qer can be estimated with higher accuracy by the following equation.
Qer = a * BLV * (Tei-Teo) + b * ΔPdPs + m
Here, a, b, and m are constants derived by experiments.
Alternatively, it can be estimated by the following equation.
Qer = a * BLV * (Tei-Teo) + b * Pd + c * Ps + m
Here, a, b, and m are constants derived by experiments.
Further, the air temperature Tei before passing through the evaporator may refer to the outside air temperature in the outside air mode, and may refer to the vehicle interior temperature in the inside air mode.

(2) Method of detecting or estimating suction pressure Ps The following (a) or (b) is performed.
(A) Actual measurement by pressure sensor (b) Estimate refrigerant pressure at the evaporator inlet from the air temperature Teo immediately after passing through the evaporator, and estimate pressure loss from the evaporator inlet to the compressor inlet by the refrigerant flow rate Gr Thus, the suction pressure Ps is estimated.
Therefore, the suction pressure Ps can be estimated by the following equation because there is a large correlation between the air temperature Teo immediately after passing through the evaporator and the refrigerant flow rate Gr.
Ps = a * Teo + b * Gr + m
Here, the refrigerant flow rate Gr may be an estimated value obtained by the method described above.

(3) Method for detecting or estimating discharge pressure Pd The following (a) or (b) is performed.
(A) Actual measurement by pressure sensor (b) A value obtained by adding an estimated value of ΔPdPs, which is the pressure difference between the discharge pressure Pd and the suction pressure Ps, to the suction pressure Ps is defined as the discharge pressure Pd. ΔPdPs can be estimated from the capacity control signal when a variable capacity compressor capable of controlling ΔPdPs is used.

(4) The compressor speed Nc can be detected by referring to the engine speed Ne of the vehicle.

  Then, the compressor torque Tc is calculated from the above equation (1) from the refrigerant flow rate Gr, discharge pressure Pd, suction pressure Ps, and compressor rotation speed Nc estimated or detected in the above (1) to (4). Can do. This calculation can be performed along a flow as shown in FIG. 10, for example.

  In the control according to the present invention, the compressor torque can be forcibly increased in a specific region in the two-dimensional map. That is, when the compressor torque limit value is a predetermined set value (for example, a negative value or a value larger than the maximum torque value), the compressor torque is forcibly increased to cool the evaporator, Even when the compressor torque limit value becomes smaller and the compressor torque decreases, it is possible to prevent the cooling capacity from being insufficient. The control for forcibly increasing the compressor torque is performed in a region where the change in the air-fuel ratio due to on / off of the compressor is small.

  As described above, in the compressor control device according to the present invention, an optimal compressor is calculated from the engine output torque and the engine speed using the two-dimensional map of the torque limit value in the biaxial plane of the engine output torque and the engine speed. By determining the torque limit value and performing control based on the torque limit value, the fuel consumption can be improved not only during acceleration but also during normal driving.

It is a characteristic view which shows the example of the switching area | region between stratified combustion and homogeneous combustion in a direct injection gasoline engine. FIG. 2 is a characteristic diagram showing a magnitude region of an air-fuel ratio difference between compressor on / off in the stratified charge combustion region of FIG. It is a characteristic view which shows the compressor torque limit value map according to each area | region of FIG. It is a flowchart which shows the procedure until it calculates | requires engine output torque from an accelerator opening. It is a schematic equipment system diagram showing an example of a vehicle air conditioner to which the present invention is applied. It is a control flow figure showing an example of compressor control performed using a torque limit value map. It is a control flow figure showing other examples of compressor control performed using a torque limit value map. It is a characteristic view which shows an example of the method of calculating | requiring a torque limiting value using a torque limiting value map. It is a characteristic view which shows the other example of the method of calculating | requiring a torque limiting value using a torque limiting value map. It is a flowchart which shows an example of compressor torque estimation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Refrigeration cycle 2 Compressor 3 Condenser 4 Receiver 5 Expansion valve 6 Evaporator 7 Detection signal of various sensors 8 Air conditioning control device 9 Capacity control signal 10 Ventilation duct 11 Blower 12 Heater 13 Air mix damper

Claims (9)

  A variable displacement compressor with variable discharge capacity, an engine speed detecting means for detecting the engine speed, an accelerator depression amount detecting means for detecting the accelerator depression amount, or an engine output torque target value calculated by an engine ECU A reference torque target value reference means; and an engine output estimation means for estimating a current engine output torque from at least an accelerator depression amount or an engine output torque target value and an engine speed, and the estimated engine output torque and the engine speed And a compressor torque limit value is determined with reference to FIG.   A variable displacement compressor with variable discharge capacity, an engine speed detecting means for detecting the engine speed, an accelerator depression amount detecting means for detecting the accelerator depression amount, or an engine output torque target value calculated by an engine ECU A reference torque target value reference means, an engine output estimation means for estimating the current engine output torque from at least the accelerator depression amount or the engine output torque target value and the engine speed, and a biaxial plane of the engine output torque and the engine speed And a torque limit value map which is a map defining a compressor torque limit value, and the compressor torque limit value is determined from the engine output torque and the engine speed using the torque limit value map. Control device.   The torque estimation means for estimating the compressor torque is provided, and the torque of the compressor is controlled so that the estimated value of the compressor torque estimated by the torque estimation means is less than or equal to the compressor torque limit value. 2 compressor control device.   The compressor control device according to claim 1, wherein when the compressor torque limit value is a specific set value, the torque of the compressor is forcibly increased.   5. The heat load detecting means for detecting the heat load on the refrigeration cycle is provided, and the compressor torque is not limited when the heat load is a predetermined value or more. The compressor control apparatus described in 1.   The compressor control device according to any one of claims 1 to 5, which is incorporated in an engine ECU.   The compressor control device according to any one of claims 2 to 6, wherein the torque limit value map is obtained by an experiment.   The compressor control device according to any one of claims 2 to 7, wherein the torque limit value map has a plurality of regions that define different compressor torque limit values.   The compressor control device according to claim 8, wherein the torque limit value map has a torque limit value region of a jump region on the map.

Images