JP6344305B2 - Vehicle air conditioning control device - Google Patents

Description

  The present invention relates to a vehicle air-conditioning control apparatus including a radiator that heats air with heat of engine coolant that is a power source of the vehicle.

  In recent years, a hybrid vehicle equipped with an engine and a motor as a power source of the vehicle has attracted attention because of the social demand for low fuel consumption and low exhaust emissions. Some of such hybrid vehicles improve the fuel efficiency by performing EV traveling in which the engine is stopped and the motor is driven. However, if the engine is operated for a long time in order to ensure the amount of heat for heating (that is, the amount of heat of engine cooling water) in winter and the like, fuel consumption tends to deteriorate.

  Therefore, for example, as described in Patent Document 1, there is a device that is equipped with a heater that heats cooling water in addition to the engine so that the engine operation for securing the amount of heat for heating can be reduced. . This includes first and second radiators (heat exchangers) for heating air with heat of engine cooling water, a heater for heating cooling water flowing toward the second radiator, And a sensible heat exchanger that transfers heat from the cooling water downstream of the radiator to the cooling water upstream of the heater, and the flow rate of the cooling water flowing through the second radiator is smaller than that of the first radiator Like to do. Thereby, while increasing the ratio of the heat radiation amount from the cooling water in the second radiator, and reducing the heat radiation amount from the engine surface, the energy consumption of the heater is reduced and the fuel consumption is improved. Yes.

Japanese Patent No. 5407944

  However, in the technique of Patent Document 1, it is necessary to provide two radiators and a sensible heat exchanger, so that the number of components of the air conditioner increases, the mounting property on the vehicle deteriorates and the cost increases. There are drawbacks. Further, the method for setting the flow rate of the cooling water is not clear, and there is a possibility that the fuel consumption cannot be sufficiently improved.

  Accordingly, the problem to be solved by the present invention is to provide an air conditioning control device for a vehicle that can improve the fuel efficiency by appropriately setting the flow rate of cooling water while satisfying the demands for improving the mounting property to the vehicle and reducing the cost. Is to provide.

  In order to solve the above-described problems, the present invention provides an engine (21) that is a power source of a vehicle, a heater (23) that heats cooling water that has passed through the engine, and heat of cooling water that has passed through the heater. In a vehicle air conditioning control device having a cooling water circuit (22) for heating in which cooling water circulates between one radiator (17) for heating air, the temperature of cooling water flowing into the engine (hereinafter referred to as "engine") An inlet water temperature setting unit (37) for setting a target engine inlet water temperature, which is a target value of the inlet water temperature, and a flow rate and specific heat of the air passing through the radiator so that the engine inlet water temperature becomes the target engine inlet water temperature. Based on the specific heat of the cooling water, a determination unit (37) that determines the flow rate of the cooling water passing through the heater is provided.

  In this configuration, since the heater for heating the cooling water is provided separately from the engine, the amount of heat necessary for heating can be ensured even if the engine inlet water temperature is lower than in a system without a heater. The target engine inlet water temperature can be set lower. And by determining the flow rate of the cooling water passing through the heater based on the flow rate of air passing through the radiator and the specific heat and the specific heat of cooling water so that the engine inlet water temperature becomes the target engine inlet water temperature, The flow rate of the cooling water for keeping the engine inlet water temperature close to the target engine inlet water temperature can be set appropriately.

  As a result, it is possible to lower the engine inlet water temperature and reduce the flow rate of the cooling water as compared with a system that does not include a heater, while ensuring the amount of heat necessary for heating. As a result, the target heating engine water temperature for stopping the engine can be set lower to shorten the engine operating time for securing the amount of heat for heating, and the air can be efficiently heated with the heat of the cooling water. The energy consumption of the heater can be reduced, and the fuel consumption can be improved. Compared to the conventional technology that provides two radiators and a sensible heat exchanger, it is possible to reduce the number of air conditioner components, which improves the ease of mounting the air conditioner on a vehicle and reduces the cost of the air conditioner. can do.

FIG. 1 is a diagram illustrating a schematic configuration of an air conditioner for a hybrid vehicle according to a first embodiment of the present invention. FIG. 2 is a block diagram showing a schematic configuration of a control system of an air conditioner for a hybrid vehicle. FIG. 3 is a time chart showing the behavior of the engine outlet water temperature when the target heating engine water temperature is set lower. FIG. 4 is a flowchart showing the flow of processing of the air conditioning control routine. FIG. 5 is a flowchart showing the flow of processing of the target engine inlet water temperature setting routine. FIG. 6 is a diagram showing engine cooling water heating characteristics. FIG. 7 is a diagram conceptually illustrating an example of a map of the cooling water flow rate lower limit value. FIG. 8 is a diagram conceptually illustrating an example of a map of the target heating engine water temperature. FIG. 9 is a time chart showing an example of the behavior of the predicted engine outlet water temperature. FIG. 10 is a diagram showing the relationship among the engine body temperature, the coolant flow rate, and the heat transfer amount. FIG. 11 is a diagram showing the relationship between the engine body temperature and the optimum flow rate. FIG. 12 is a diagram conceptually illustrating an example of a map of correction values for the target engine inlet water temperature. FIG. 13 is a diagram illustrating a schematic configuration of an air conditioner for a hybrid vehicle according to a fourth embodiment. FIG. 14 is a diagram conceptually illustrating an example of a map of the engine body temperature.

  Hereinafter, some embodiments embodying the mode for carrying out the present invention will be described.

A first embodiment of the present invention will be described with reference to FIGS.
First, a schematic configuration of an air conditioner for a hybrid vehicle will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1, an outside air introduction path 12 for introducing outside air, which is air outside the passenger compartment, and an inside air, which is air inside the passenger compartment, are introduced into the upstream portion of the air conditioning case 11 that forms an air passage for air conditioning. The inside air introduction path 13 is formed. An outside air temperature sensor 31 that detects outside air temperature is provided in the outside air introduction path 12. On the other hand, the inside air introduction path 13 is provided with an inside / outside air switching door 14 that opens and closes the inside air introduction path 13. The inside / outside air switching door 14 is driven by a motor or the like (not shown).

  On the downstream side of the outside air introduction path 12 and the inside air introduction path 13, a blower fan 15 that blows air in the direction of the air conditioner outlet (that is, the direction in the passenger compartment) is disposed, and air is supplied to the downstream side of the blower fan 15. An evaporator 16 for cooling is arranged. The evaporator 16 and a compressor, condenser, gas-liquid separator, expansion valve, and the like (not shown) constitute a refrigeration cycle.

  A heater core 17, which is a heat radiator for heating air, is disposed downstream of the evaporator 16 in the air conditioning case 11, and a bypass passage 18 that bypasses the heater core 17 and flows air to the side of the heater core 17. Is formed.

  On the upstream side of the heater core 17 and the bypass passage 18, an air mix door 19 that adjusts the air volume ratio between the warm air passing through the heater core 17 and the cold air passing through the bypass passage 18 is provided. The warm air that has passed through the heater core 17 and the cold air that has passed through the bypass passage 18 are mixed in the air mixing section 20 on the downstream side of the heater core 17 and the bypass passage 18 and blown toward the air conditioner outlet.

  The air mix door 19 is driven by a motor or the like (not shown). The air mix door 19 adjusts the air volume ratio between the warm air passing through the heater core 17 and the cool air passing through the bypass passage 18 to adjust the temperature of air blown into the vehicle interior. A vehicle interior temperature sensor 32 (see FIG. 2) for detecting the vehicle interior temperature is provided in the vehicle interior.

  Further, an engine 21 that is an internal combustion engine and a motor generator (not shown) are mounted as power sources for the vehicle. In the cooling water circuit 22 for heating through which the cooling water of the engine 21 circulates, one heater 23 that heats the cooling water that has passed through the engine 21 and the heat of the cooling water that has passed through the heater 23 heat the air. One heater core 17 is provided.

  Specifically, an electric water pump 24 is provided in the vicinity of the inlet of the cooling water passage (so-called water jacket) of the engine 21. Further, the outlet of the cooling water passage of the engine 21 and the cooling water inlet of the heater core 17 are connected by a cooling water circulation passage 25, and a heater 23 is provided in the middle of the cooling water circulation passage 25. Further, the cooling water outlet of the heater core 17 and the suction port of the electric water pump 24 are connected by a cooling water circulation passage 26. Thereby, the cooling water circuit 22 for heating through which cooling water circulates among the engine 21, the heater 23, and the heater core 17 is formed.

  The heater core 17 heats the air by exchanging heat between the cooling water and the air. The heater 23 is a heat exchanger of the heat pump 27 and heats the cooling water by exchanging heat between the cooling water and the refrigerant. The heat pump 27 compresses the low-temperature and low-pressure gas refrigerant into a high-temperature and high-pressure gas refrigerant with the electric compressor 28, and then releases heat from the high-temperature and high-pressure gas refrigerant into the high-pressure liquid refrigerant with the heater 23. Thereafter, the high-pressure liquid refrigerant is decompressed and expanded by the expansion valve 29 to form a low-temperature and low-pressure liquid refrigerant, and the outdoor heat exchanger 30 absorbs heat into the low-temperature and low-pressure liquid refrigerant to form a low-temperature and low-pressure gas refrigerant.

  The cooling water circulation passage 25 is provided with an engine outlet water temperature sensor 33 that detects an engine outlet water temperature that is the temperature of the cooling water flowing out from the engine 21. The cooling water circulation channel 26 is provided with an engine inlet water temperature sensor 34 that detects an engine inlet water temperature that is the temperature of the cooling water flowing into the engine 21. Further, the engine 21 is provided with an engine temperature sensor 35 for detecting the temperature of the engine body (for example, a cylinder block).

  As shown in FIG. 2, the outputs of the various sensors 31 to 35 described above are input to the air conditioner ECU 37. The air conditioner ECU 37 is mainly composed of a microcomputer, and executes an air conditioning control program stored in a built-in ROM (storage medium), thereby allowing an air conditioner (for example, the electric water pump 24, the blower fan 15, The inside / outside air switching door 14, the air mix door 19, the electric compressor 28, etc.) are controlled.

  The hybrid ECU 36 is a computer that comprehensively controls the entire vehicle. The hybrid ECU 36 transmits and receives control signals and data signals to and from the air conditioner ECU 37, the engine ECU 38 that controls the engine 21, the MG-ECU 39 that controls the motor generator, and the like. The ECUs 37 to 39 control the air conditioner, the engine 21, the motor generator, and the like according to the state of the vehicle.

  By the way, the hybrid vehicle can improve the fuel efficiency by performing the EV traveling in which the engine 21 is stopped and the motor generator travels. However, when a heating request is generated and a high water temperature target is imposed, it becomes difficult to stop the engine 21 and fuel consumption is reduced. As a countermeasure, as shown in FIG. 3, the target heating engine water temperature for stopping the engine is set lower (for example, about the same as the engine warm-up completion water temperature), and the cooling water temperature is set at the engine outlet by the heater 23 other than the engine 21. By heating from the water temperature to the target heating water temperature, the engine operating time for securing the amount of heat for heating can be shortened. At this time, if the flow rate of the cooling water is large as in the case of the vehicle not equipped with the heater 23 other than the engine 21, a huge amount of energy is required for the heater 23, which is difficult to realize or can be realized. Fuel consumption cannot be improved due to power consumption. The fuel economy improvement point at the time of heating is to set the output of the heater 23 and the flow rate of the cooling water so as to reduce the output of the heater 23 other than the engine 21 while lowering the target heating engine water temperature. The reason why large heating energy is required when the flow rate of cooling water is large is that the difference between the heat mass (specific heat x flow rate) of the cooling water supplying the heat and the air that heats the passenger compartment is large (that is, the heat mass of the cooling water is larger) This is because the temperature of the cooling water needs to be raised to the target air temperature (target heating water temperature) in order to realize the target vehicle interior temperature.

Therefore, in the first embodiment, when the generated heat of the engine 21 is relatively small, for example, during low-speed running in winter, the air conditioner ECU 37 executes the routines shown in FIGS. As a result, the target engine inlet water temperature, which is the target value of the engine inlet water temperature, is set to be lower than that of the system not provided with the heater 23, and passes through the heater core 17 so that the engine inlet water temperature becomes the target engine inlet water temperature. The flow rate of the cooling water passing through the heater 23 is determined based on the flow rate and specific heat of the air and the specific heat of the cooling water. Thereby, the engine inlet water temperature is lowered and the flow rate of the cooling water is reduced as compared with a system that does not include the heater 23 while securing the amount of heat necessary for heating.
Hereinafter, the processing content of each routine of FIG.4 and FIG.5 which the air-conditioner ECU37 performs in the present Example 1 is demonstrated.

[Air conditioning control routine]
The air conditioning control routine shown in FIG. 4 is repeatedly executed by the air conditioner ECU 37 at a predetermined cycle. When this routine is started, first, in step 101, a target vehicle interior temperature is acquired based on a signal from an air conditioner setting panel or the like. Further, the outside air temperature detected by the outside air temperature sensor 31 and the vehicle interior temperature detected by the vehicle interior temperature sensor 32 are read.

  Thereafter, the process proceeds to step 102, where the target heater core inlet water temperature (that is, the target heating water temperature) is calculated by a map or a mathematical formula based on the outside air temperature, the vehicle interior temperature, and the target vehicle interior temperature. Here, the target heater core inlet water temperature is a target value of the heater core inlet water temperature that is the temperature of the cooling water flowing into the heater core 17.

  Thereafter, the process proceeds to step 103, and it is determined whether or not the passenger compartment temperature is equal to or higher than a predetermined value. Here, the predetermined value is set to a temperature (for example, 20 ° C.) at which glass such as a windshield of a vehicle starts to become fogged. The predetermined value may be a fixed value set in advance, or may be changed according to the outside air temperature, humidity, or the like.

  If it is determined in step 103 that the passenger compartment temperature is lower than the predetermined value, the routine proceeds to step 104 where the engine inlet water temperature detected by the engine inlet water temperature sensor 34 and the engine body temperature detected by the engine temperature sensor 35 are detected. Then, the engine outlet water temperature detected by the engine outlet water temperature sensor 33 is read.

  Thereafter, the process proceeds to step 105, and the flow rate of the air passing through the heater core 17 is calculated based on the rotational speed of the blower fan 15 or the like by using a map or a mathematical expression. Further, the temperature of the air flowing into the heater core 17 is estimated based on the outside air temperature, the passenger compartment temperature, the opening degree of the inside / outside air switching door 14 and the like, and the specific heat of the air is calculated by a map or a mathematical formula based on the temperature of the air. To do. Further, the specific heat of the cooling water is calculated based on the engine outlet water temperature or the like by a map or a mathematical formula, and the flow rate of the cooling water is calculated based on the rotational speed of the electric water pump 24 or the like based on the map or the mathematical formula.

Thereafter, the process proceeds to step 106, and a target engine inlet water temperature that is a target value of the engine inlet water temperature is set by executing a target engine inlet water temperature setting routine of FIG.
Thereafter, the process proceeds to step 107, and the cooling water passing through the heater 23 is based on the flow rate and specific heat of the air passing through the heater core 17 and the specific heat of the cooling water so that the engine inlet water temperature becomes the target engine inlet water temperature. The flow rate and the output of the heater 23 are determined. The processing in step 107 serves as a determination unit in the claims.

  In order to lower the operating rate of the engine 21, it is necessary to keep the engine inlet water temperature low. In the first embodiment, when the output of the heater 23 (that is, the cooling water heating amount of the heater 23) is set to a predetermined value, the engine inlet water temperature is lowered while realizing the target heater core inlet water temperature necessary for heating. Calculate the cooling water flow rate required for

Hereinafter, the calculation method of the coolant flow rate of the first embodiment will be described.
The air heating amount [kW] of the heater core 17 is expressed by the following (1) using the air flow rate Qa [kg / s] passing through the heater core 17 and the air specific heat Ca [kJ / kg / K] and Δair temperature [K]. ) Expression. Here, Δair temperature [K] is the difference between the heater core outlet air temperature [° C.] which is the temperature of the air flowing out from the heater core 17 and the heater core inlet air temperature [° C.] which is the temperature of the air flowing into the heater core 17 ( = Heater core outlet air temperature-heater core inlet air temperature).
Heater core air heating amount = Qa × Ca × Δ air temperature (1)

The heat dissipation amount [kw] of the heater core 17 is expressed by the following (2) using the cooling water flow rate Qw [kg / s] passing through the heater core 17, the cooling water specific heat Cw [kJ / kg / K], and the Δ water temperature [K]. ) Expression. Here, the Δ water temperature [K] is a difference between the heater core inlet water temperature [° C.] that is the temperature of the cooling water flowing into the heater core 17 and the heater core outlet water temperature [° C.] that is the temperature of the cooling water flowing out of the heater core 17 (= Heater core inlet water temperature−heater core outlet water temperature).
Heater core heat dissipation = Qw × Cw × Δ water temperature (2)

The heater core inlet water temperature [° C.] is calculated using the engine inlet water temperature [° C.], the cooling water temperature increase ΔT 1 [K] by the engine 21, and the cooling water temperature increase ΔT 2 [K] by the heater 23, It can be represented by the following formula (3).
Heater core inlet water temperature = engine inlet water temperature + ΔT1 + ΔT2 (3)

The temperature increase ΔT1 [K] can be expressed by the following equation (4) using the cooling water heating amount H1 [kW] of the engine 21.
ΔT1 = H1 / (Qw × Cw) (4)

The temperature increase ΔT2 [K] can be expressed by the following equation (5) using the cooling water heating amount H2 [kW] of the heater 23.
ΔT 2 = H 2 / (Qw × Cw) (5)

In the above formulas (1) and (2), the following formula (6) can be obtained by setting “heater core air heating amount = heater core heat dissipation amount”.
Qw = Qa × Ca × Δair temperature / (Cw × Δwater temperature) (6)

Further, using the relationship of “Δ water temperature = heater core inlet water temperature−heater core outlet water temperature” and the above equations (3) to (5), the following equation (7) can be obtained.
Δwater temperature = engine inlet water temperature + (H1 + H2) / (Qw × Cw) −heater core outlet water temperature
... (7)

From the above formulas (6) and (7), the following formula (8) can be obtained.
Qw = {Qa × Ca × Δair temperature− (H 1 + H 2)}
/ {(Engine inlet water temperature-heater core outlet water temperature) × Cw}
... (8)

The relational expressions for calculating the cooling water flow rate Qw for maintaining the engine inlet water temperature at the target value (that is, the target engine inlet water temperature) are summarized below.
Qw = {Qa × Ca × Δair temperature− (H 1 + H 2)}
/ {(Engine inlet water temperature-heater core outlet water temperature) × Cw}
... (A)
Qw <(H1 + H2) / {Cw × (target heater core inlet water temperature−engine inlet water temperature)}
... (B)
H1 = f (Qw) (C)
Here, the above equation (B) is a condition for establishing the target heater core inlet water temperature necessary for heating.

  Using the above equations (A) to (C), the cooling water flow rate Qw passing through the heater 23 is calculated so that the engine inlet water temperature becomes the target engine inlet water temperature. Here, air flow rate Qa, air specific heat Ca, cooling water specific heat Cw, Δair temperature, engine inlet water temperature-heater core outlet water temperature, target heater core inlet water temperature, engine inlet water temperature, and cooling water heating amount H2 of heater 23 are respectively shown below. The case where the numerical value is assumed will be described.

Air flow rate Qa = 0.09 [kg / s]
Air specific heat Ca = 1.0 [kJ / kg / K]
Cooling water specific heat Cw = 3.7 [kJ / kg / K]
ΔAir temperature = 60 [K]
Engine inlet water temperature-Heater core outlet water temperature = 2 [K]
Target heater core inlet water temperature = 60 [℃]
Engine inlet water temperature = Target engine inlet water temperature (eg 40 [° C])
Heating amount of cooling water H2 of heater 23 = 5 [kW]

First, based on the cooling water heating characteristic of the engine 21 shown in FIG. 6 (the relationship between the cooling water flow rate Qw and the cooling water heating amount H1 of the engine 21), the above equation (C) is set by the following approximate equation.
^{H1 = -388.26 Qw 3 + 52.3Qw 2} +16.07 Qw-0.3195 ... (C)

Then, each numerical value is substituted into the above formula (A) to obtain the following formula (D).
Qw = {5.4− (H1 + 5)} / − 7.4 (D)
Furthermore, the following equation can be obtained from the above equations (C) and (D).
7.4 Qw + 5.4 - (- 388.26Qw 3 + 52.3Qw 2 +16.07 Qw-0.3195 + 5) = 0

The following three solutions can be obtained by solving the above equation.
Qw = -0.134, 0.0690, 0.200
Also, the following equation (E) is obtained by substituting each numerical value into the equation (B).
Qw <(− 388.26Qw ³ + 52.3Qw ² +16.07 Qw−0.3195 + 5) / (3.7 × 20)
... (E)

Qw = 0.0690 is selected as a final solution from the above three solutions as a solution that satisfies the constraints defined by the above equation (E) and Qw> 0.
From the above, the cooling water flow rate Qw = 0.0690 [kg / s] = 4.14 [L / min] is determined.
The air conditioner ECU 37 controls the electric water pump 24 and the like so that the flow rate of the cooling water passing through the heater 23 becomes the cooling water flow rate Qw.

  On the other hand, if it is determined in step 103 that the vehicle interior temperature is equal to or higher than the predetermined value, the process proceeds to step 108 and the flow rate of the cooling water passing through the heater 23 is set to be lower than that in the case where the vehicle interior temperature is less than the predetermined value. To do more. The processing of step 108 also serves as a determining unit in the claims.

  When the flow rate of cooling water decreases, the difference in heater core inlet / outlet temperature (that is, the difference between the heater core inlet water temperature and the heater core outlet water temperature) increases, and the temperature difference due to the position of the air outlet in the passenger compartment increases (for example, the foot is 60 ° C.) And the vicinity of the face may be 40 ° C). Because of this, the following two types of problems may occur, so the processing of step 108 is performed as a countermeasure.

  As the passenger compartment temperature increases, the glass tends to fog up. In order to increase the blowing temperature of the defroster in order to prevent fogging of the windshield, which is important for safety, the temperature difference between the heater core inlet and outlet becomes a problem. This is because the air in the defroster section is warmed by the cooling water near the heater core outlet. Therefore, in order to ensure the anti-fogging performance, when the passenger compartment temperature increases, the flow rate of the cooling water is increased to reduce the temperature difference between the inlet and outlet of the heater core and to keep the outlet temperature of the defroster high.

  In addition, while the temperature in the passenger compartment is low, there is no significant effect, but as the passenger compartment temperature increases, the low temperature side blowout temperature may become a problem. Therefore, when comfort is prioritized over fuel efficiency, the flow rate of the cooling water is increased when the passenger compartment temperature is increased, thereby reducing the heater core inlet / outlet temperature difference and keeping all the outlet temperatures high.

  Specifically, referring to the map of the cooling water flow rate lower limit value shown in FIG. 7, the cooling water flow rate lower limit value is calculated according to the passenger compartment temperature, and the cooling water flow rate is lower than the cooling water flow rate lower limit value. Increases the cooling water flow rate to the lower limit value of the cooling water flow rate. As a result, the coolant flow rate is set to be larger than when the vehicle interior temperature is less than a predetermined value. The map of the lower limit value of the coolant flow rate is set so that the lower limit value of the coolant flow rate increases as the passenger compartment temperature increases.

  Thereafter, the process proceeds to step 109, and a target heating engine water temperature, which is a target value of the engine outlet water temperature, is set according to the output of the heater 23 and the flow rate of the cooling water passing through the heater 23. The process of step 109 serves as an outlet water temperature setting unit in the claims.

  Specifically, the target heating engine water temperature corresponding to the output of the heater 23 and the coolant flow rate is calculated with reference to the target heating engine water temperature map shown in FIG. The target heating engine water temperature map is set so that the target heating engine water temperature increases (that is, approaches the target heating water temperature) as the output of the heater 23 decreases. The target heating engine water temperature map is set so that the target heating engine water temperature increases as the cooling water flow rate increases in areas other than the low flow rate region where the cooling water flow rate is relatively low. Since the heat transfer efficiency of the heater 23 is lowered, the target heating engine water temperature is set higher as the cooling water flow rate decreases.

[Target engine inlet water temperature setting routine]
The target engine inlet water temperature setting routine shown in FIG. 5 is a subroutine executed in step 106 of the air conditioning control routine of FIG. 4 and serves as an inlet water temperature setting unit in the claims. In this routine, the load on the engine 21 is predicted based on travel information on the planned travel route of the vehicle, and the target engine inlet water temperature is set based on the prediction result.

  For example, when driving on a suburban road or highway, if the vehicle speed or acceleration is high, the cooling water temperature will rise even if it is heated, but when driving on a traffic jam road or a road with many traffic lights As described above, when the vehicle speed and acceleration are small, the cooling water temperature is lowered by the outside air and heating. If the cooling water temperature increases, the output of the heater 23 other than the engine 21 can be reduced to improve fuel efficiency. However, if the cooling water temperature is greatly reduced at low load continuously, the engine 21 may be forced to operate. Fuel consumption deteriorates. Therefore, when a low water temperature is predicted, the target engine inlet water temperature is raised before that to prevent an extreme decrease in the cooling water temperature.

  When this routine is started, first, in step 201, based on information from the navigation device, information from the in-vehicle camera, information received from another vehicle (for example, a preceding vehicle), etc., travel information on the planned travel route of the vehicle (For example, traffic jam conditions, road gradients, signal conditions, etc.) are acquired.

  Thereafter, the process proceeds to step 202, where changes in the vehicle speed and road gradient from the current value to a predetermined distance (for example, 5 km) ahead are predicted based on the travel information on the planned travel route, and the predicted change in vehicle speed and road gradient, etc. Based on the above, a change in engine load up to a predetermined distance is predicted.

  Thereafter, the process proceeds to step 203, where the heating load up to the predetermined distance is predicted based on the outside air temperature, the target heating water temperature (that is, the target heater core inlet water temperature) and the travel time required up to the predetermined distance.

  Thereafter, the process proceeds to step 204, and a change in the engine outlet water temperature up to a predetermined distance is predicted based on the predicted engine load (that is, the heating side load) and the heating load (that is, the heat radiation side load) (see FIG. 9). ).

Thereafter, the process proceeds to step 205, where it is determined whether or not the predicted engine outlet water temperature is equal to or higher than a high temperature side threshold (= current target engine inlet water temperature + predetermined value).
If it is determined in step 205 that the predicted engine outlet water temperature is equal to or higher than the high temperature side threshold value, the process proceeds to step 206 and the high temperature side excess time and the high temperature side excess amount where the predicted engine outlet water temperature is equal to or higher than the high temperature side threshold value. (= Predicted maximum value of engine outlet water temperature−high temperature side threshold value) is predicted. The target engine inlet water temperature is corrected in the low temperature direction according to the predicted high temperature side excess time and the high temperature side excess amount. This eliminates the need to consider the risk that the engine outlet water temperature will become extremely low in the future, so the target engine inlet water temperature is set to be lower in consideration of only the current fuel efficiency improvement.

  On the other hand, if it is determined in step 205 that the predicted engine outlet water temperature is not equal to or higher than the high temperature side threshold value, the process proceeds to step 207 where the predicted engine outlet water temperature is the low temperature side threshold value (= current target engine inlet water temperature− It is determined whether or not the value is equal to or less than a predetermined value.

  If it is determined in step 207 that the predicted engine outlet water temperature is equal to or lower than the low temperature side threshold value, the process proceeds to step 208 and the low temperature side excess time and the low temperature side excess amount where the predicted engine outlet water temperature is equal to or lower than the low temperature side threshold value. (= Low temperature side threshold−predicted minimum value of engine outlet water temperature) is predicted. The target engine inlet water temperature is corrected in the high temperature direction according to the predicted low temperature side excess time and the low temperature side excess amount. This prevents the engine outlet water temperature from becoming too low.

  In the first embodiment described above, the target engine inlet water temperature is set lower than in the system not including the heater 23, and the air passing through the heater core 17 is set so that the engine inlet water temperature becomes the target engine inlet water temperature. Based on the flow rate and specific heat and the specific heat of the cooling water, the flow rate of the cooling water passing through the heater 23 is determined. Thereby, the cooling water flow rate for keeping the engine inlet water temperature close to the target engine inlet water temperature can be set appropriately, and compared with a system that does not include the heater 23 while ensuring the amount of heat necessary for heating, The flow rate of cooling water can be reduced by lowering the engine inlet water temperature. As a result, the target heating engine water temperature for stopping the engine can be set lower to shorten the engine operation time for securing the amount of heat for heating, and efficiently heat the air with the heat of the cooling water. Thus, the energy consumption of the heater 23 can be reduced, and fuel consumption can be improved. Compared to the conventional technology that provides two radiators and a sensible heat exchanger, it is possible to reduce the number of air conditioner components, which improves the ease of mounting the air conditioner on a vehicle and reduces the cost of the air conditioner. can do.

  In the first embodiment, the engine load is predicted based on travel information on the planned travel route of the vehicle, and the target engine inlet water temperature is set based on the prediction result. As a result, it is possible to prevent the engine outlet water temperature from becoming too high or too low, and to suppress forced operation of the engine 21 due to a decrease in the engine outlet water temperature.

  In the first embodiment, when the passenger compartment temperature is equal to or higher than a predetermined value, the flow rate of the cooling water passing through the heater 23 is set to be larger than when the passenger compartment temperature is lower than the predetermined value. As a result, the heater core inlet / outlet temperature difference can be reduced, the blowing temperature of the defroster can be kept high, the anti-fogging performance of the glass can be secured, and all the blowing temperatures can be kept high, thereby improving the comfort. Can be secured.

  In the first embodiment, the target heating engine water temperature is set according to the output of the heater 23 and the flow rate of the cooling water passing through the heater 23. Thereby, even when restrictions are imposed on the output of the heater 23 for reasons such as power shortage and parts protection, the target heating engine water temperature can be increased and the cooling water temperature can be raised to the target heating water temperature. .

Next, a second embodiment of the present invention will be described. However, description of substantially the same parts as those in the first embodiment will be omitted or simplified, and different parts from the first embodiment will be mainly described.
In the first embodiment, in step 107 of the routine of FIG. 4, the flow rate of the air passing through the heater core 17 and the output of the heater 23 are set to a predetermined value so that the engine inlet water temperature becomes the target engine inlet water temperature. The flow rate of the cooling water passing through the heater 23 is determined based on the specific heat and the specific heat of the cooling water.

  Also in the second embodiment, the routine of FIG. 4 described in the first embodiment is executed. At this time, in the second embodiment, in step 107, the flow rate of the air passing through the heater core 17 and the heater core 17 so that the cooling water heating amount of the heater 23 is minimized under the condition that the engine inlet water temperature is the target engine inlet water temperature. Based on the specific heat and the specific heat of the cooling water, the output of the heater 23 and the flow rate of the cooling water passing through the heater 23 are determined.

Hereinafter, the calculation method of the output of the heater 23 and the coolant flow rate of the second embodiment will be described.
In the second embodiment, the cooling water heating amount H2 of the heater 23 is used as a variable, and the cooling water heating amount H2 of the heater 23 is minimized using the expressions (A) to (C) described in the first embodiment as constraints. Solve the following optimization problem:

Minimize: H2
Subject to:
Qw = {Qa × Ca × Δair temperature− (H 1 + H 2)}
/ {(Engine inlet water temperature-heater core outlet water temperature) × Cw}
Qw <(H1 + H2) / {Cw × (target heater core inlet water temperature−engine inlet water temperature)}
H1 = f (Qw)

Specifically, first, as in the first embodiment, based on the cooling water heating characteristics of the engine 21 shown in FIG.
^{H1 = -388.26 Qw 3 + 52.3Qw 2} +16.07 Qw-0.3195 ... (C)

Then, each numerical value is substituted into the above equation (A) to obtain the following equation (F).
Qw = {5.4− (H1 + H2)} / − 7.4 (F)
Further, the following equation (G) is obtained from the above equations (C) and (F).
H2 = 7.4 Qw + 5.4 - ( - 388.26Qw 3 + 52.3Qw 2 +16.07 Qw-0.3195)
... (G)

Further, the following equation (H) is obtained by substituting each numerical value into the equation (B).
H2> Qw × (3.7 × 20) − (− 388.26Qw ³ + 52.3Qw ² +16.07 Qw−0.3195)
... (H)

The following optimization problem of minimizing the cooling water heating amount H2 of the heater 23 is solved by using the expressions (G), (H), and (C) as constraints.
Minimize: H2
Subject to:
H2 = 7.4 Qw + 5.4 - ( - 388.26Qw 3 + 52.3Qw 2 +16.07 Qw-0.3195)
H2> Qw × (3.7 × 20) − (− 388.26Qw ³ + 52.3Qw ² +16.07 Qw−0.3195)
^{H1 = -388.26 Qw 3 + 52.3Qw 2} +16.07 Qw-0.3195)
As a result, H2 = 4.8 and Qw = 0.08 can be obtained as a solution.

Thus, the output H2 of the heater 23 = 4.8 [kW] and the cooling water flow rate Qw = 0.08 [kg / s] = 4.5 [L / min] are determined.
Although the output of the heater 23 and the cooling water flow rate may be calculated by the above-described method at a predetermined calculation cycle, the output of the heater 23 and the cooling water flow rate calculated for each condition in advance by the above-described method. May be stored in the ROM of the air conditioner ECU 37, and the output of the heater 23 and the coolant flow rate corresponding to the current conditions may be called at a predetermined calculation cycle.

  In the second embodiment described above, the flow rate of air passing through the heater core 17 and the specific heat and the cooling water so that the cooling water heating amount of the heater 23 is minimized under the condition that the engine inlet water temperature is the target engine inlet water temperature. On the basis of the specific heat, the output of the heater 23 and the flow rate of the cooling water passing through the heater 23 are determined. Thereby, the cooling water heating amount of the heater 23 can be minimized within a range in which the engine inlet water temperature can be maintained near the target engine inlet water temperature, and the fuel efficiency improvement effect can be further enhanced.

  Next, Embodiment 3 of the present invention will be described with reference to FIGS. However, description of substantially the same parts as those of the second embodiment will be omitted or simplified, and different parts from the second embodiment will be mainly described.

  As shown in FIG. 10, when the engine load increases and the temperature of the engine body increases, the temperature difference between the engine 21 and the cooling water increases, so that the transmission efficiency (heat exchange efficiency) decreases due to a decrease in the cooling water flow rate. In addition, the absolute value of the decrease in the amount of heat transfer from the engine 21 to the cooling water increases. When the absolute value of the decrease in the heat transfer amount increases, the influence on the fuel efficiency effect due to the change in the coolant flow rate increases. For this reason, as shown in FIG. 11, when the engine load is large and the engine body temperature is high, the optimum flow rate, which is the coolant flow rate that provides the best fuel efficiency, is greater than when the engine load is small and the engine body temperature is low. . That is, the cooling water heating characteristic (see FIG. 6) of the engine 21 changes according to the engine load and the engine body temperature, and the optimum flow rate changes.

Therefore, in the third embodiment, the output of the heater 23 and the flow rate of the cooling water passing through the heater 23 are corrected according to the engine body temperature.
Specifically, the air conditioner ECU 37 calculates a correction value according to the engine body temperature with reference to the correction value map of the target engine inlet water temperature shown in FIG. 12, and uses this correction value to calculate the target engine inlet water temperature. By correcting, the target engine inlet water temperature is corrected according to the engine body temperature. In this case, for example, the target engine inlet water temperature is increased as the engine body temperature is higher. Then, when calculating the output of the heater 23 and the flow rate of the cooling water passing through the heater 23 in step 107 of the routine of FIG. 4, the corrected target engine inlet water temperature is used in accordance with the engine body temperature. Thus, the output of the heater 23 and the flow rate of the cooling water passing through the heater 23 are corrected.

  In the third embodiment described above, the output of the heater 23 and the flow rate of the cooling water passing through the heater 23 are corrected according to the engine body temperature. Thereby, the coolant flow rate is corrected and the coolant flow rate is set to the optimum flow rate in response to the change in the coolant flow characteristic of the engine 21 and the optimum flow rate according to the engine body temperature. Can do.

  In the third embodiment, the target engine inlet water temperature is corrected according to the engine body temperature. However, the present invention is not limited to this. For example, the engine load (for example, the intake pressure of the engine 21 or the intake air amount) is corrected. Accordingly, the output of the heater 23 and the flow rate of the cooling water passing through the heater 23 may be corrected by correcting the target engine inlet water temperature. Alternatively, the output of the heater 23 and the flow rate of the cooling water passing through the heater 23 are corrected by correcting the target engine inlet water temperature according to the engine oil temperature or the engine cooling water heating amount as substitute information of the engine body temperature. You may make it correct | amend. Further, by correcting the target engine inlet water temperature according to two or three of the engine body temperature, the engine load, and the engine outlet water temperature, the output of the heater 23 and the flow rate of the cooling water passing through the heater 23 can be adjusted. You may make it correct | amend. Further, the output of the heater 23 and the heater are corrected by correcting the cooling water heating characteristic of the engine 21 (that is, the expression (C)) according to at least one of the engine body temperature, the engine load, and the engine outlet water temperature. You may make it correct | amend the flow volume of the cooling water which passes 23. FIG.

  Next, Embodiment 4 of the present invention will be described with reference to FIG. However, substantially the same parts as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted or simplified, and parts different from those in the first embodiment are mainly described.

  In the fourth embodiment, as shown in FIG. 13, the heating coolant circuit 22 is provided with a bypass passage 40 that bypasses the heater 23 and the heater core 17 and flows the coolant. The bypass passage 40 is connected to the upstream side of the heater 23 in the cooling water circulation passage 25 and the downstream side of the heater core 17 in the cooling water circulation passage 26.

  Further, an electromagnetically driven flow rate adjustment valve 41 (for example, a three-way valve) is provided at a connection portion (that is, a branch portion) between the cooling water circulation passage 25 and the bypass passage 40. The flow rate adjusting valve 41 adjusts the ratio of the flow rate A of the cooling water passing through the heater 23 and the flow rate B of the cooling water flowing through the bypass passage 40 to thereby adjust the flow rate of the cooling water passing through the engine 21 (A + B). And the flow rate A of the cooling water passing through the heater 23 can be adjusted.

  The air conditioner ECU 37 controls the electric water pump 24 and the flow rate adjusting valve 41 so that the flow rate A of the cooling water passing through the heater 23 becomes the cooling water flow rate Qw calculated in step 107 of the routine of FIG.

  In the fourth embodiment described above, the flow rate (A + B) of the cooling water passing through the engine 21 and the flow rate A of the cooling water passing through the heater 23 can be individually controlled. Thereby, the flow rate of the cooling water passing through the engine 21 is larger than the flow rate of the cooling water passing through the heater 23 while controlling the flow rate of the cooling water passing through the heater 23 to the target value (cooling water flow rate Qw). Thus, the heat transfer efficiency of the engine 21 can be maintained high, or local heating inside the engine 21 can be avoided.

  In each of the first to fourth embodiments, the engine body temperature is detected by the engine temperature sensor 35. However, in the case of a system that does not include the engine temperature sensor 35, the engine body temperature is estimated. Also good. In this case, for example, as shown in FIG. 14, a map of the engine body temperature is created in advance with the parameters of the engine inlet / outlet water temperature difference (that is, the difference between the engine outlet water temperature and the engine inlet water temperature) and the amount of cooling water passing through the engine 21 as parameters. And remember. Referring to this map, the engine body temperature is calculated according to the difference between the engine inlet / outlet water temperature and the amount of cooling water passing through the engine 21.

  In the first to fourth embodiments, the engine inlet water temperature sensor 34 detects the engine inlet water temperature. However, in the case of a system that does not include the engine inlet water temperature sensor 34, the engine inlet water temperature is estimated. Anyway. In this case, for example, the engine inlet water temperature is estimated (calculated) as follows.

(a) The output of the heater 23 is calculated by the following equation using the output command value of the heater 23 and the average efficiency.
Heater output = output command value x average efficiency

(b) The output of the heater core 17 is calculated by the following equation using the air flow rate, the specific air heat, the heater core outlet air temperature, and the heater core inlet air temperature.
Heater core output = Air flow rate x Air specific heat
× (Heater core outlet air temperature-Heater core inlet air temperature)

At that time, the air flow rate is calculated by a map or a mathematical formula based on the command value of the blower fan 15. The heater core inlet air temperature is calculated by a map or a mathematical formula based on the outside air temperature, the passenger compartment temperature, and the opening degree of the inside / outside air switching door 14. The heater core outlet air temperature is calculated by the following equation using the heater core inlet air temperature, the output of the heater 23, the air flow rate, and the air specific heat.
Heater core outlet air temperature = heater core inlet air temperature + heater output / air flow rate / specific air heat

  (c) The heat radiation of the piping of the cooling water circuit 22 for heating is calculated by a map or a mathematical formula based on the cooling water flow rate, the cooling water temperature (for example, the engine outlet water temperature), and the temperature in the engine (that is, the temperature in the engine room). At this time, the internal temperature of the engine is calculated by a map or a mathematical formula based on the outside air temperature, the vehicle speed, and the engine body temperature.

Thus, after calculating the output of the heater 23, the output of the heater core 17, and the pipe heat dissipation, the engine inlet water temperature, the output of the heater 23, the output of the heater core 17, the output of the heater core 17, the pipe heat dissipation, and the cooling water flow rate are calculated. It calculates by following Formula using cooling specific heat.
Engine inlet water temperature = Engine outlet water temperature
+ (Heater output-heater core output-piping heat dissipation) / cooling water flow rate / cooling specific heat

  Moreover, in each said Examples 1-4, although the heater (heat exchanger) of the heat pump 27 was used as a heater which heats the cooling water which passed the engine 21, it is not limited to this, For example, A PTC heater, a sheathed heater, a combustion heater, an exhaust heat recovery device, or the like may be used.

  In each of the first to fourth embodiments, the coolant flow rate and the heater output are determined so that the engine inlet water temperature becomes the target engine inlet water temperature, but the engine outlet water temperature is set to the target engine outlet water temperature. The cooling water flow rate and the heater output may be determined.

Further, in each of the first to fourth embodiments, some or all of the functions executed by the air conditioner ECU 37 may be configured by hardware using one or a plurality of ICs.
In addition, the present invention is not limited to an air conditioner for a hybrid vehicle, and may be applied to an air conditioner such as a plug-in hybrid vehicle, a range extender, and an engine vehicle (gasoline vehicle or diesel vehicle) equipped with an idle stop function.

  DESCRIPTION OF SYMBOLS 17 ... Heater core (radiator), 21 ... Engine, 22 ... Heating cooling water circuit, 23 ... Heater, 37 ... Air-conditioner ECU (inlet water temperature setting part, determination part, outlet water temperature setting part)

Claims (7)

An engine (21) that is a power source of the vehicle, a heater (23) that heats the cooling water that has passed through the engine, and a radiator (17) that heats the air with the heat of the cooling water that has passed through the heater; In an air conditioning control device for a vehicle provided with a cooling water circuit for heating (22) through which cooling water circulates between
An inlet water temperature setting unit (37) for setting a target engine inlet water temperature that is a target value of the temperature of cooling water flowing into the engine (hereinafter referred to as "engine inlet water temperature");
Determination of determining the flow rate of cooling water passing through the heater based on the flow rate and specific heat of the air passing through the radiator and the specific heat of cooling water so that the engine inlet water temperature becomes the target engine inlet water temperature An air conditioning control device for a vehicle, comprising: a unit (37).   The determination unit is configured to reduce a flow rate of air passing through the radiator and a specific heat and cooling water so that a cooling water heating amount of the heater is minimized under a condition that the engine inlet water temperature is set to the target engine inlet water temperature. The air conditioning control device for a vehicle according to claim 1, wherein the output of the heater and the flow rate of the cooling water passing through the heater are determined based on the specific heat.   The determining unit is configured to output the heater and the flow rate of the cooling water passing through the heater according to at least one of the engine temperature, the engine load, and the temperature of the cooling water flowing out from the engine. The air conditioning control device for a vehicle according to claim 2, wherein:   The said inlet water temperature setting part predicts the load of the said engine based on the driving | running | working information in the driving | running | working planned path | route of the said vehicle, The said target engine inlet water temperature is set based on the prediction result, The Claim 1 thru | or 4. The air conditioning control device for a vehicle according to any one of 3.   The said determination part makes the flow volume of the cooling water which passes the said heater larger than the case where the said vehicle interior temperature is less than the said predetermined value when the vehicle interior temperature is more than predetermined value. 5. The air conditioning control device for a vehicle according to any one of 4 to 4.   An outlet water temperature setting unit (37) for setting a target heating engine water temperature, which is a target value of the temperature of the cooling water flowing out from the engine, according to the output of the heater and the flow rate of the cooling water passing through the heater; The air conditioning control device for a vehicle according to any one of claims 1 to 5, wherein   The flow rate adjusting valve (41) capable of adjusting a ratio between a flow rate of the cooling water passing through the engine and a flow rate of the cooling water passing through the heater is provided. An air conditioning control device for a vehicle as described in 1.

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