JP2011189817A - Air-conditioning control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that, when a condition that temperature of an evaporator 30 exceeds a target value is included in restart conditions of idle stop control, the automatic stop time of the engines 10 is shortened as the temperature rising speed of the evaporator 30 during the automatic stop of an engine 10 becomes high and the fuel consumption reducing effect of the engine 10 is reduced. <P>SOLUTION: When a running state of a vehicle is determined to be immediately before a stop, an air capacity gradual reduction process for gradually reducing air blowing amount of an evaporator blower 44 is performed. Then, when the vehicle is determined to be stopping based on an output value of a vehicle speed sensor 64, a high temperature side target evaporator temperature setting process for raising the target value forcibly is performed and also an air capacity gradual increase process, for gradually increasing air blowing amount of the evaporator blower 44 is performed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention includes a compressor that is driven by the power of an internal combustion engine to compress refrigerant, and an evaporator that evaporates the refrigerant discharged from the compressor and cools the air in the vehicle. The present invention relates to a vehicle air-conditioning control apparatus that is applied to a vehicle including an air conditioning system and operates the compressor so as to control the temperature of the evaporator or a parameter value correlated therewith to a target value.

  As this type of control device, as shown in Patent Document 1 below, a control device that corrects the idle rotation speed of an internal combustion engine in accordance with the deviation between the temperature of the evaporator and its target value (target temperature) is known. Yes. Specifically, considering that the compressor drive torque increases as the difference between the evaporator temperature and the target temperature increases, the idle rotation speed is set higher as the value obtained by subtracting the target temperature from the evaporator temperature increases. ing. As a result, the generated torque of the internal combustion engine in the idle operation state can be matched with the driving torque of the compressor.

JP 2004-353470 A

  By the way, when the load of the internal combustion engine is low (low load state) such as an idle operation state, the thermal efficiency of the internal combustion engine is usually lowered due to an increase in the ratio of the cooling loss to the amount of heat generated by the combustion. Increases fuel consumption. Here, when the compressor is driven in a situation where the fuel consumption rate of the internal combustion engine is high, there is a possibility that the fuel consumption amount of the internal combustion engine increases due to an increase in the degree of increase in fuel consumption accompanying the drive of the compressor. is there.

  The present invention has been made to solve the above-described problems, and the object thereof is to suitably increase the fuel consumption of the internal combustion engine accompanying the driving of the compressor when the operation state of the internal combustion engine is a low load state. An object of the present invention is to provide a vehicle air-conditioning control device that can be easily suppressed.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

  The invention described in claim 1 includes a compressor that is driven by the power of the internal combustion engine to compress the refrigerant, and an evaporator that evaporates the refrigerant discharged from the compressor and cools the air in the vehicle interior. In a vehicle air-conditioning control apparatus, which is applied to a vehicle including an air conditioning system configured as described above, and operates the compressor to control the temperature of the evaporator or a parameter value correlated therewith to a target value thereof, When the operating state of the internal combustion engine is in a low load state, forcibly increasing means for forcibly increasing the target value is provided.

  In order to reduce the temperature of the evaporator, it is required to increase the refrigerant discharge amount of the compressor in order to increase the refrigerant circulation amount of the refrigeration cycle. Here, when the refrigerant discharge amount of the compressor is increased, the driving torque of the compressor increases, and the fuel consumption of the internal combustion engine accompanying the driving of the compressor increases. In the above invention, the target value (target temperature) is forcibly increased when the operating state of the internal combustion engine is a low load state. For this reason, in the situation where the fuel consumption rate of the internal combustion engine becomes high, the refrigerant discharge amount of the compressor can be reduced, and the driving torque of the compressor can be reduced. Thereby, the increase in the fuel consumption of the internal combustion engine accompanying the drive of a compressor can be suppressed suitably.

  The invention according to claim 2 is the invention according to claim 1, wherein the air conditioning system includes a fan for blowing air cooled by the evaporator to the interior of the passenger compartment, An air volume setting means for setting the air flow rate of the fan, a predicting means for predicting whether or not the operating state of the internal combustion engine will shift to a low load state, and a case where the prediction means predicts shifting to a low load state The air flow reducing means for reducing the air flow rate of the fan with respect to the set air flow rate, and when the target value is increased by the forced increase means, the air flow rate of the fan is set to the set air flow rate. And an air volume gradually increasing means for gradually increasing the air volume.

  When the amount of blown air from the fan increases, heat exchange between the refrigerant and the air is promoted in the evaporator, so that the temperature rise rate of the evaporator increases and the temperature of the evaporator tends to increase. Here, when the temperature of the evaporator becomes high, there is a possibility that the comfort in the passenger compartment cannot be properly maintained. For this reason, it is also conceivable to reduce the air flow rate of the fan in order to suppress the rise in the temperature of the evaporator. However, if the air flow rate of the fan is reduced, there is a concern that the comfort in the passenger compartment cannot be properly maintained in combination with the target temperature being increased by the forced increase means.

  Here, the present inventors set the above after reducing the air flow rate of the fan set by the air volume setting means when it is predicted to shift to a low load state of the internal combustion engine where the target temperature is forcibly increased. It has been found that by gradually increasing the air flow rate of the fan toward the air flow rate, it is possible to reduce the temperature rise rate of the evaporator and maintain the comfort in the passenger compartment as much as possible. In view of this point, in the above-described aspect, by gradually increasing the air flow rate of the fan in the above-described aspect, it is possible to suitably suppress an increase in the fuel consumption amount of the internal combustion engine while maintaining the comfort in the passenger compartment as much as possible.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the vehicle includes an automatic stop start unit that performs an automatic stop process and a restart process of the internal combustion engine. Includes a condition that the temperature of the evaporator or the value of the parameter exceeds the target value, and the low load state includes a state in which the internal combustion engine is automatically stopped.

  In the above invention, by providing the forcibly increasing means, it is possible to lengthen the time until the condition of exceeding the target value is satisfied. As a result, the time during which the internal combustion engine is automatically stopped can be extended, and as a result, the fuel consumption reduction effect of the internal combustion engine can be suitably improved. In addition, when the invention includes the air volume gradually increasing means, it is possible to reduce the temperature increase rate of the evaporator while maintaining the comfort of the passenger compartment as much as possible. Can be long.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the air conditioning system includes a heater that reheats the air cooled by the evaporator, Means for controlling cooling of the vehicle with the reheated air, and heating amount reducing means for reducing the amount of reheating by the heater when the operating state of the internal combustion engine is in a low load state. It is characterized by providing.

  In the above invention, when the target temperature is set low and the temperature of the evaporator becomes excessively low, etc., the situation where the temperature of the air supplied into the vehicle becomes excessively low and the comfort in the vehicle interior is impaired is avoided. Therefore, cooling control is performed with reheated air. Here, when the target temperature is raised by the forcible raising means, the temperature of the air supplied into the vehicle compartment rises, and there is a possibility that the comfort in the vehicle compartment cannot be properly maintained. In this regard, in the above-described invention, an increase in the temperature of the air supplied to the passenger compartment is suppressed by reducing the amount of reheating by the heater in a low load state of the internal combustion engine in which the target temperature is forcibly increased. Thereby, the increase in the fuel consumption of an internal combustion engine can be suppressed suitably, maintaining the comfort of a vehicle interior as much as possible.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the evaporator has a cold storage function of storing heat of the refrigerant.

  In the said invention, by giving a cold storage function to an evaporator, it can suppress that the calorie | heat amount required in order to cool the air in a vehicle interior is insufficient, and can suppress the raise of the temperature of an evaporator as much as possible. Thereby, the comfort in a vehicle interior can be improved more suitably.

The system block diagram concerning one Embodiment. The flowchart which shows the procedure of the idle stop control process concerning one Embodiment. The flowchart which shows the procedure of the cooling control process concerning one Embodiment. The time chart which shows the air_conditioning | cooling control processing concerning one Embodiment.

  Hereinafter, an embodiment in which a vehicle air conditioning control device according to the present invention is applied to a vehicle (automobile) equipped with an internal combustion engine (engine) will be described with reference to the drawings.

  FIG. 1 shows the overall configuration of an engine system and an air conditioning system (air conditioner system) according to this embodiment.

  As shown in the figure, each cylinder of the engine 10 is provided with a fuel injection valve 12 for supplying fuel to the combustion chamber of the engine 10. The energy generated by the combustion of the mixture of the supplied fuel and intake air is taken out as rotational power of the output shaft (crankshaft 14) of the engine 10. A crank angle sensor 18 that detects the rotation angle of the crankshaft 14 is provided in the vicinity of the crankshaft 14.

  A starter 20 is connected to the crankshaft 14. The starter 20 is started by turning on an ignition switch (not shown), and applies initial rotation (cranking) to the crankshaft 14 to start the engine 10.

  On the other hand, the air conditioner system includes an air passage 22 that supplies warm air or cold air into the passenger compartment, and a refrigeration apparatus for cooling the air flowing through the air passage 22.

  The refrigeration apparatus includes a compressor 24 that sucks and discharges refrigerant to circulate the refrigerant in the refrigeration cycle, a condenser 26, a receiver 28, an evaporator 30 (evaporator), and the like.

  The compressor 24 is a variable capacity compressor capable of continuously and variably setting the refrigerant discharge capacity by an energization operation of an electromagnetically driven control valve (CV 24a) included in the compressor 24. A pulley 32 mechanically connected to the drive shaft of the compressor 24 is mechanically connected to the crankshaft 14 via a belt 34 and a crank pulley 36. Under the situation where the rotational power of the crankshaft 14 is transmitted to the compressor 24, the discharge capacity is adjusted by energizing the CV 24a.

  The condenser 26 is a member that exchanges heat between air blown from a fan (not shown) that is rotationally driven by a DC motor or the like, and refrigerant discharged from the compressor 24. The receiver 28 is provided for gas-liquid separation of the refrigerant flowing from the condenser 26, temporarily storing the separated liquid refrigerant, and supplying only the liquid refrigerant to the downstream side.

  The liquid refrigerant stored in the receiver 28 is rapidly expanded into a mist by the temperature type expansion valve 38, and the mist refrigerant is supplied to the evaporator 30. The evaporator 30 is provided in the air passage 22. In the evaporator 30, a part or all of the refrigerant is vaporized by heat exchange between the air flowing through the air passage 22 and the mist-like refrigerant. Thereby, the air flowing through the air passage 22 is cooled.

  In addition, the evaporator 30 is used as a heat accumulator that stores the heat of the refrigerant by a regenerator 40 (for example, paraffin) enclosed in the evaporator 30. This is a configuration for accumulating a surplus amount of heat for cooling generated in the refrigeration cycle during driving of the compressor 24 and cooling the vehicle interior during a period in which the engine 10 is automatically stopped by idle stop control described later. It is. Specifically, the heat of the refrigerant is stored in the evaporator 30 by heat exchange between the refrigerant supplied to the evaporator 30 and the cool storage agent 40 by driving the compressor 24. Thereafter, the air flowing through the air passage 22 is cooled by exchanging heat between the air flowing through the air passage 22 and the cool storage agent 40 under the situation where the compressor 24 is stopped. An evaporator temperature sensor 42 is provided in the vicinity of the air-side outlet of the evaporator 30 to detect the temperature of the air exchanged by the evaporator 30 (the air-side outlet temperature of the evaporator 30, hereinafter, the actual evaporator temperature). Further, the refrigerant flowing out of the evaporator 30 is sucked into the suction port of the compressor 24.

  On the other hand, in addition to the evaporator 30, the air passage 22 heats a fan (evaporation blower 44) that is rotated by a DC motor or the like to generate an air flow in the air passage 22, and air flowing through the air passage 22. A heater core 46 and the like are provided.

  Inside the heater core 46, cooling water for the engine 10 supplied from a cooling water pipe (not shown) flows. In the heater core 46, the air flowing through the air passage 22 is heated by heat exchange between the air flowing through the air passage 22 and the cooling water.

  The air blown by the evaporator blower 44 passes through the evaporator 30 and the heater core 46 and is subjected to heat exchange so as to reach a desired temperature. Specifically, the evaporator 30 is provided so as to block the entire air passage 22 on the downstream side of the evaporator 44, and the heater core 46 is provided so as to partially close the air passage 22 on the downstream side of the evaporator 30. An air mix door 48 driven by a servo motor or the like is provided between the evaporator 30 and the heater core 46. The air mix door 48 adjusts the ratio of the amount of air passing through the heater core 46 and the amount of air bypassing the heater core 46 according to the stop position. Thereby, the temperature of the air flowing through the air passage 22 is adjusted, and the vehicle interior is cooled by supplying the temperature-adjusted air to the vehicle interior via an air outlet (not shown) provided in the vehicle interior.

  An electronic control device (hereinafter referred to as an air conditioner ECU 50) for operating an air conditioner system is mainly configured by a microcomputer including a known CPU, ROM, RAM, and the like. The air conditioner ECU 50 detects an A / C switch 52 that is a drive command for the compressor 24 to cool the passenger compartment, a target temperature setting switch 54 that sets a target value (target indoor temperature) of the passenger compartment temperature, and a passenger compartment temperature. An output signal from the vehicle interior temperature sensor 56, the evaporation temperature sensor 42, and the like is input. The air conditioner ECU 50 operates various devices such as the EVA blower 44, the CV 24a, and further the air mix door 48 by executing various control programs stored in the ROM in response to these inputs. Then, by operating these various devices, cooling control of the vehicle interior such as drive control of the EVA blower 44 and the compressor 24 is performed.

  The drive control of the EVA blower 44 adjusts the voltage applied to the EVA blower 44 in order to control the air volume (blower air volume) of the EVA blower 44. Specifically, the higher the voltage applied to the EVA blower 44, the greater the blower air volume. Further, in the drive control of the compressor 24, the CV 24a is energized so as to control the actual evaporator temperature calculated from the output value of the evaporator temperature sensor 42 to the target value (target evaporator temperature).

  An electronic control device (hereinafter referred to as an engine ECU 58) whose operation target is an engine system is mainly configured by a microcomputer including a known CPU, ROM, RAM, and the like. The engine ECU 58 includes a brake sensor 60 that detects the amount of operation of the brake pedal of the driver, an accelerator sensor 62 that detects the amount of operation of the accelerator pedal of the driver, a vehicle speed sensor 64 that detects the traveling speed of the vehicle, and a crank angle sensor. An output signal such as 18 is input. Further, the engine ECU 58 and the air conditioner ECU 50 exchange information by performing bidirectional communication. Specifically, the engine ECU 58 receives a signal from the air conditioner ECU 50 such as the A / C switch 52. On the other hand, the air conditioner ECU 50 receives signals from the brake sensor 60 and the vehicle speed sensor 64 output from the engine ECU 58.

  In response to the input, the engine ECU 58 executes various control programs stored in the ROM, thereby performing combustion control of the engine 10 such as fuel injection control by the fuel injection valve 12. In particular, the engine ECU 58 performs an idle stop control process for the engine 10. The idle stop control process executes a process of automatically stopping the engine 10 when a predetermined stop condition is satisfied while the engine 10 is in operation, and then the engine 10 is operated by the starter 20 when the predetermined restart condition is satisfied. The process to be restarted is executed. Thereby, the fuel consumption reduction effect of the engine 10 can be obtained. Hereinafter, the idle stop control will be described in detail with reference to FIG.

  FIG. 2 shows a procedure of idle stop control processing according to the present embodiment. This process is repeatedly executed by the engine ECU 58 at a predetermined cycle, for example.

  In this series of processing, it is first determined in step S10 whether or not the engine 10 is automatically stopped.

  If it is determined in step S10 that the engine 10 is not automatically stopped, the process proceeds to step S12, and it is determined whether or not a stop condition for the engine 10 is satisfied. In the present embodiment, the stop condition is a condition that the logical product of the condition that the brake operation is performed and the condition that the vehicle traveling speed SPD becomes 0 is true. Note that whether or not the brake operation is being performed may be determined based on the output value of the brake sensor 60. Further, the vehicle traveling speed SPD may be calculated based on the output value of the vehicle speed sensor 64.

  If it is determined in step S12 that the stop condition of the engine 10 is satisfied, the process proceeds to step S14, and the engine 10 is automatically stopped. Here, the automatic stop process is a process of stopping the engine 10 by stopping the fuel injection from the fuel injection valve 12.

  On the other hand, if it is determined in step S10 that the engine 10 is automatically stopped, the process proceeds to step S16, and it is determined whether or not a restart condition for the engine 10 is satisfied. In the present embodiment, the restart condition is a condition that the logical sum of the condition that the brake operation is not performed and the condition that the actual evaporator temperature exceeds the target evaporator temperature is true. Here, the conditions for the actual evacuation temperature are set for the purpose of maintaining as much as possible the comfort in the passenger compartment by the cooling control. That is, during the automatic stop of the engine 10, the compressor 24 is not driven, and the actual evaporator temperature gradually increases. When the actual evacuated temperature rises, the temperature of the air supplied from the outlet to the passenger compartment (air outlet temperature) gradually increases, which may cause discomfort to the passenger. For this reason, by providing a condition for the actual evaporation temperature, the engine 10 is restarted when the actual evaporation temperature becomes high, and the actual evaporation temperature is lowered by driving the compressor 24.

  If it is determined in step S16 that the restart condition of the engine 10 is satisfied, the process proceeds to step S18 and the engine 10 is restarted. Here, the restart process is a process of restarting the engine 10 that has been automatically stopped by performing cranking by starting the starter 20 and starting fuel injection from the fuel injection valve 12.

  If a negative determination is made in steps S12 and S16, or if the processes in steps S14 and S18 are completed, the series of processes is temporarily terminated.

  According to the idling stop control, the restart condition is satisfied when the actual evaporation temperature exceeds the target evaporation temperature, and the engine 10 is restarted. However, when the time (automatic stop time) from when the automatic stop process is executed to when the restart process is executed is short, there is a concern that the fuel consumption reduction effect by the idle stop control cannot be sufficiently obtained. Therefore, in the present embodiment, by performing the following cooling control process, the fuel consumption reduction effect of the engine 10 is improved by extending the automatic stop time of the engine 10 while maintaining the comfort in the passenger compartment as much as possible.

  FIG. 3 shows the procedure of the cooling control process according to the present embodiment. This process is repeatedly executed by the air conditioner ECU 50 at a predetermined cycle, for example, on condition that the A / C switch 52 is turned on.

  In this series of processes, it is first determined in step S20 whether or not the vehicle is stopped. This process is a process for determining whether or not the automatic stop process of the engine 10 is being executed. Here, whether or not the vehicle is stopped may be determined based on whether or not the traveling speed SPD of the vehicle is zero.

  If it is determined in step S20 that the vehicle is not stopped, the process proceeds to step S22, and a target evaporation temperature normal time setting process, which is a process of setting the target evaporation temperature based on the target indoor temperature, is performed. The target evaporator temperature is set so as to realize the outlet temperature required for setting the vehicle interior temperature as the target indoor temperature. Specifically, the target evacuation temperature is set to a temperature range (for example, 4 to 10 ° C.) that is sufficiently lower than the temperature range that can be required as the outlet temperature (required blowing temperature range, for example, 15 to 20 ° C.). Here, in the present embodiment, when the actual evaporator temperature is excessively lowered, a part of the air cooled in the evaporator 30 is reheated in the heater core 46 so that the actual outlet temperature falls within the required outlet temperature range. The air mix door 48 is operated as described above. The target room temperature may be calculated based on the output value of the target temperature setting switch 54.

  On the other hand, if it is determined in step S20 that the vehicle is stopped, it is determined that an automatic stop process of the engine 10 is being executed, and in step S24, the target evaporation temperature is set to the target evaporation temperature normal time. A process of forcibly increasing the target value set by the setting process (target evaporator temperature high temperature side setting process) is performed. In the present embodiment, the target evaporation temperature is set on condition that the outlet temperature is set to be equal to or lower than the upper limit value of the required outlet temperature range. Specifically, the outlet temperature is set to a value as high as possible (for example, 13 ° C.) that can be set to be equal to or lower than the upper limit value of the required outlet temperature range. This process is a process for improving the fuel consumption reduction effect of the engine 10 while satisfying the request for the outlet temperature. That is, when the target evaporator temperature is increased, the time until the actual evaporator temperature exceeds the target evaporator temperature during the automatic stop of the engine 10 is increased, and the automatic stop time of the engine 10 is increased. Further, when the target evaporator temperature is increased, the driving torque of the compressor 24 required for lowering the actual evaporator temperature to the target evaporator temperature in the idle operation state after the engine 10 is restarted decreases.

  It should be noted that when setting the target evaporator temperature by the target evaporator temperature high temperature side setting process, the degree of dehumidification in the evaporator 30 by stopping the compressor 24 from the viewpoint of maintaining the comfort of the passenger compartment as much as possible while the engine 10 is automatically stopped. It is desirable to have a value that can suppress the air humidity at the air outlet from excessively rising or the occurrence of an unpleasant odor of the air at the air outlet due to the decrease.

  After the processes in steps S22 and S24 are completed, a process for setting a blower air volume (reference air volume) as a reference is performed in step S26. In the present embodiment, the reference air volume is set based on the deviation between the vehicle interior temperature calculated from the output value of the vehicle interior temperature sensor 56 and the target indoor temperature. Specifically, the reference air volume may be increased as the value obtained by subtracting the target indoor temperature from the vehicle interior temperature increases.

  In subsequent steps S28 to S34, an air volume gradually decreasing process that is a process of gradually decreasing the blower air volume with respect to the reference air volume and an air volume gradually increasing process that is a process of gradually increasing the blower air volume toward the reference air volume are performed. Hereinafter, these processes will be described in detail.

  When the blower air volume increases, the evaporator 30 promotes heat exchange between the refrigerant and the air. Here, when heat exchange is promoted during the automatic stop of the engine 10, the time until the actual evaporator temperature exceeds the target evaporator temperature is shortened, so that the automatic stop time of the engine 10 is shortened and the fuel consumption reduction effect of the engine 10 is reduced. There is a concern that the degree of improvement will be small. For this reason, in order to lengthen the automatic stop time, it is conceivable to reduce the blower air volume during the automatic stop of the engine 10. However, if the blower air volume is reduced while the engine 10 is automatically stopped, there is a concern that the comfort in the passenger compartment cannot be properly maintained.

  In order to solve these problems, the present inventors conducted various examinations and experiments on the air volume setting method of the EVA blower 44 for maintaining the comfort in the passenger compartment as much as possible while improving the fuel consumption reduction effect. By performing the air volume gradually increasing process while the engine 10 is automatically stopped, it is possible to reduce the rate of increase in the actual temperature and to maintain the comfort of the passenger compartment as much as possible while extending the automatic stop time of the engine 10. I found out.

  However, in order to perform the air volume gradually increasing process, it is necessary to temporarily reduce the blower air volume with respect to the reference air volume before starting this process. Here, for example, if the blower air volume is suddenly reduced at the time when the automatic stop process of the engine 10 is executed, there is a risk of giving the passenger discomfort. Therefore, in the present embodiment, based on the running state of the vehicle, it is predicted whether or not to shift to a situation where the automatic stop process of the engine 10 is executed, and when it is predicted to shift, the air volume gradual decrease process is performed, The comfort of the passenger compartment is maintained as much as possible while the air volume gradually increasing process can be executed.

  Specifically, first, in step S28, it is determined whether or not the traveling state of the vehicle is immediately before stopping. This process is a process for predicting whether or not to shift to a situation where the automatic stop process of the engine 10 is executed. In the present embodiment, the logical product of the condition that the vehicle traveling speed SPD is higher than 0 and less than the specified speed K (> 0) and the condition that the brake operation is performed is true. When it is determined, it is determined that the traveling state of the vehicle is immediately before stopping.

  If it is determined in step S28 that the running state of the vehicle is immediately before stopping, the process proceeds to step S30, and the air volume gradual reduction process is performed. Here, the air volume gradually decreasing process will be described. In the present embodiment, a correction amount that is gradually increased every time an affirmative determination is made in the process of step S28 is calculated, and this correction amount is used as the reference air volume set in the process of step S26. The blower airflow command value (command airflow) is calculated as a value subtracted from. Then, the blower air volume is gradually decreased by performing drive control of the EVA blower 44 based on the commanded air volume. Here, the initial value of the correction amount is set to 0, and the correction amount may be stored in the memory of the air conditioner ECU 50 each time. Further, the degree of reduction (decrease rate) in the blower air volume by the air volume gradual reduction process may be set from the viewpoint of not causing discomfort to the occupant.

  Note that when the traveling state of the vehicle is a deceleration state, the drive control of the compressor 24 may be performed so that the kinetic energy of the vehicle is converted into the drive energy of the compressor 24. At this time, it is desirable to perform the drive control so that the discharge capacity of the compressor 24 becomes the maximum capacity. Thereby, in the period of the deceleration state including the period during which the air volume gradual reduction process is executed, the actual evaporator temperature can be lowered by sufficiently storing the amount of heat for cooling control in the evaporator 30, and the engine 10 is automatically stopped. It becomes possible to make time longer. Here, whether the traveling state of the vehicle is a deceleration state is determined by, for example, a logical product of a condition that the change speed of the traveling speed SPD of the vehicle is a negative value and a condition that the brake operation is performed. It may be determined based on whether or not is true.

  On the other hand, if it is determined in step S28 that the running state of the vehicle is not immediately before stopping, the process proceeds to step S32 to determine whether or not the commanded air volume is less than the reference air volume. This process is a process for determining whether or not a process for performing drive control of the EVA blower 44 (normal drive process) is performed using the commanded air volume as the reference air volume.

  If it is determined in step S32 that the normal drive process is not being performed, the air volume gradually decreasing process is performed immediately before, and it is determined that the commanded air volume is lower than the reference air volume. In step S34, the air volume gradually increasing. Processing and processing for reducing the reheating amount in the heater core 46 (reheating amount reduction processing) are performed. Here, the air volume gradually decreasing process will be described. In this embodiment, each time an affirmative determination is made in the process of step S32, the command air volume is calculated by adding a predetermined amount (> 0) to the command air volume calculated immediately before. To do. Then, the blower air volume is gradually increased by performing drive control of the EVA blower 44 based on the commanded air volume. The degree of increase (increase speed) of the blower air volume by the air volume gradual increase process is set from the viewpoint of making the automatic stop time of the engine 10 as long as possible. For example, a value at which the increase speed of the actual evaporator temperature does not increase transiently. Should be set.

  On the other hand, the reheating amount lowering process will be described. This process is performed when the automatic stop process of the engine 10 is executed under the condition that the cooling control is performed using the air reheated in the heater core 46. This is a process for maintaining the sex as much as possible. That is, for example, under the situation where the actual evaporation temperature increases due to the stop of the compressor 24, the reheat amount in the heater core 46 is reduced, thereby suppressing the increase in the outlet temperature. The reheating amount reduction process is a process of operating the air mix door 48 so as to gradually reduce the reheating amount in the heater core 46 in order to avoid a situation in which the outlet temperature suddenly changes and gives the passenger an uncomfortable feeling. Is desirable.

  On the other hand, if a negative determination is made in the process of step S32, the process proceeds to step S36, and the normal drive process is performed. When the normal drive process is performed, the correction amount calculated in the process of step S30 is initialized (set to 0).

  In addition, when the process of step S30, S34, S36 is completed, this series of processes is once complete | finished.

  FIG. 4 shows an example of the cooling control process according to the present embodiment. Specifically, FIG. 4A shows the transition of the vehicle running speed SPD, FIG. 4B shows the transition of the engine speed NE based on the output value of the crank angle sensor 18, and FIG. 4C shows the target. FIG. 4 (d) shows the transition of the blower air volume, FIG. 4 (e) shows the transition of the actual evaporator temperature, and FIG. 4 (f) shows the transition of the outlet temperature.

  As shown in the figure, when the vehicle starts traveling at time t1, the target evaporator temperature is set by the target evaporator temperature normal time setting process. Thereafter, the vehicle travel speed SPD becomes 0 and the engine 10 from the time point (time t2) when the travel state of the vehicle is determined to be immediately before stopping when the travel speed SPD of the vehicle falls below the specified speed K by the brake operation of the driver. The air volume gradual reduction processing is performed until the time when the automatic stop is performed (time t3). Then, at time t3, the target evaporator temperature is forcibly increased by the target evaporator temperature high temperature side setting process, and the air volume gradually increasing process is started. Thereafter, the engine 10 is restarted when the actual evaporator temperature exceeds the target evaporator temperature Tα at time t4, and the target evaporator temperature is set by the target evaporator temperature normal time setting process at time t5 when the vehicle starts to travel again.

  As described above, in the present embodiment, the engine 10 is automatically controlled while maintaining the comfort in the passenger compartment by the cooling control as much as possible by the above-described target evaporator temperature high temperature side setting process, air volume gradually decreasing process, air volume gradually increasing process, and reheating amount decreasing process. The fuel consumption reduction effect of the engine 10 can be improved by increasing the stop time or suppressing the increase in the driving torque of the compressor 24.

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) When it is determined that the vehicle is stopped, a target evaporator temperature high temperature side setting process, which is a process for forcibly increasing the target evaporator temperature higher than that set when the vehicle is running, is performed. As a result, the automatic stop time of the engine 10 can be lengthened, and an increase in the driving torque of the compressor 24 when the engine 10 is restarted can be suppressed. As a result, the fuel consumption reduction effect of the engine 10 can be suitably improved. Can be made.

  (2) When it is determined that the running state of the vehicle is immediately before stopping, an air volume gradual reduction process that is a process of gradually decreasing the blower air volume with respect to the reference air volume is performed. As a result, it is possible to avoid a sudden decrease in the blower air volume due to the air volume gradual increase process, and it is possible to suppress the occurrence of a situation in which the passenger feels uncomfortable.

  (3) After the air volume gradually decreasing process, the air volume gradually increasing process, which is a process of gradually increasing the blower air volume toward the reference air volume, was performed. Accordingly, the fuel consumption reduction effect of the engine 10 is preferably improved by extending the automatic stop time of the engine 10, and the comfort of the vehicle interior by the cooling control is maintained as much as possible by suppressing the fluctuation of the outlet temperature. Can do.

  (4) When cooling control is performed using air reheated in the heater core 46, a reheating amount reduction process is performed while the engine 10 is automatically stopped. Thereby, the raise of blower outlet temperature can be suppressed and by extension the comfort of a vehicle interior can be maintained as much as possible.

  (5) The evaporator 30 was provided with a cold storage function by enclosing the cold storage agent 40 inside the evaporator 30. As a result, the increase in the actual evaporation temperature during the automatic stop of the engine 10 can be suppressed as much as possible, and the automatic stop time of the engine 10 can be extended. Therefore, the fuel consumption reduction effect of the engine 10 can be preferably improved.

(Other embodiments)
The above embodiment may be modified as follows.

  -In above-mentioned embodiment, although the air side exit temperature of the evaporator 30 was controlled to the target evaporation temperature, it is not restricted to this. For example, a sensor for detecting the temperature of the fin of the evaporator 30 (evaporator surface temperature) may be provided, and the evaporator surface temperature calculated based on the output value of this sensor may be controlled to the target value. Further, for example, a sensor that detects the temperature of the refrigerant flowing in the evaporator 30 or the refrigerant side outlet temperature of the evaporator 30 may be provided, and the refrigerant temperature calculated based on the output value of the sensor may be controlled to the target value. Further, for example, a sensor for detecting the outlet temperature may be provided, and the outlet temperature calculated based on the output value of the sensor may be controlled to the target value.

  The vehicle to which the present invention is applied is not limited to the vehicle that performs idle stop control, and may be a vehicle that does not perform this control. In this case, an increase in fuel consumption of the engine 10 in the idle operation state with low thermal efficiency can be suitably suppressed by performing the target evaporation temperature high temperature side setting process in the idle operation state. This is because the driving torque of the compressor 24 is set to 0 when the actual evaporation temperature is lower than the target evaporation temperature. Further, when it is determined by the process of step S28 in FIG. 3 that the operating state of the engine 10 shifts to the idle operation state, the air volume gradual decrease process is performed, and then the air volume gradual increase process is performed. A decrease in comfort can be suppressed as much as possible.

  Further, the vehicle is not limited to a vehicle having only the engine 10 as a travel power source, but may be a hybrid vehicle having an electric motor together with the engine 10 as a travel power source. Even in this case, if the compressor 24 is driven using the engine 10 as a power source, the application of the present invention is effective in suppressing the driving of the compressor 24 in an idle operation state with low thermal efficiency as much as possible.

  In the above embodiment, the target evaporation temperature high temperature side setting process may be performed even in the idle operation state.

  The method for forcibly increasing the target evaporation temperature is not limited to the one exemplified in the above embodiment. For example, the target evaporator temperature set by the target evaporator temperature normal time setting process may be increased by a predetermined temperature.

  In the above embodiment, the normal drive process is performed when it is determined in step S32 of FIG. 3 that the commanded air volume becomes the reference air volume, that is, when it is determined that the air volume gradually decreasing process is completed, but this is not a limitation. . For example, when it is determined that the vehicle starts to travel during the air volume gradual increase process (time t5 in FIG. 4), the normal drive process may be performed.

  -The restart conditions of the engine 10 for the actual evaporator temperature are not limited to those exemplified in the above embodiment. For example, the condition may be that the actual evaporation temperature exceeds a temperature (specified temperature) that is higher than the target evaluation temperature by a specified value. In this case, it is desirable to limit the upper limit value of the specified temperature, which varies depending on the target evaporator temperature, with the target evaporator temperature set by the target evaporator temperature high temperature side setting process.

  -The air volume gradually increasing process is not limited to the one that increases the blower air volume monotonously and strongly. For example, the maximum value and the minimum value of the blower air volume may be gradually increased while the increase and decrease are periodically repeated. As a result, the average value of the blower air volume can be increased monotonously with an increase in the actual EVA temperature.

  -In above-mentioned embodiment, when it was judged that the driving | running | working state of a vehicle is just before a stop, although the air volume gradual reduction process was performed, it is not restricted to this. For example, when it is determined that the vehicle is just before stopping, a process of reducing (rapidly decreasing) the blower air volume in a short time may be performed instead of the air volume gradual reduction process. However, it is desirable to perform the air volume gradual reduction process from the viewpoint of suppressing discomfort given to the passenger.

  In the above embodiment, the compressor 24 is a variable displacement compressor, but is not limited thereto. For example, a fixed capacity compressor having a constant discharge capacity during driving may be used.

  In the above embodiment, the evaporator 30 has a function for storing cold, but the present invention is not limited thereto, and this function may not be provided.

  DESCRIPTION OF SYMBOLS 10 ... Engine, 12 ... Fuel injection valve, 20 ... Starter, 24 ... Compressor, 30 ... Evaporator, 40 ... Cold storage agent, 42 ... Eva temperature sensor, 44 ... Eva blower, 50 ... Air conditioner ECU (one implementation of vehicle air conditioning control device) (Form), 58 ... engine ECU.

Claims (5)

An air conditioning system comprising: a compressor that is driven by the power of an internal combustion engine to compress refrigerant; and an evaporator that evaporates refrigerant discharged and supplied from the compressor to cool air in the passenger compartment. In a vehicle air-conditioning control apparatus that is applied to a vehicle equipped with and operates the compressor to control the temperature of the evaporator or a value of a parameter correlated therewith to a target value thereof,
An air conditioning control device for a vehicle comprising: a forcibly increasing means for forcibly increasing the target value when the operating state of the internal combustion engine is a low load state. The air conditioning system includes a fan that blows air to the evaporator so as to supply air cooled by the evaporator into a vehicle interior.
An air volume setting means for setting an air volume of the fan;
Predicting means for predicting whether or not the operating state of the internal combustion engine shifts to a low load state;
When it is predicted by the predicting means to shift to a low load state, an air volume lowering means for reducing the fan's air volume with respect to the set air volume;
2. The vehicle air conditioning according to claim 1, further comprising: an air volume gradually increasing unit that gradually increases the air flow rate of the fan toward the set air flow rate when the target value is increased by the forcibly increasing unit. Control device. The vehicle includes automatic stop start means for performing automatic stop processing and restart processing of the internal combustion engine,
The execution condition of the restart process includes a condition that the temperature of the evaporator or the value of the parameter exceeds the target value,
The vehicle air conditioning control device according to claim 1, wherein the low load state includes a state in which the internal combustion engine is automatically stopped. The air conditioning system includes a heater that reheats the air cooled by the evaporator,
Means for performing cooling control in the vehicle by the reheated air;
The heating amount reducing means for reducing the amount of reheating by the heater when the operating state of the internal combustion engine is in a low load state, further comprising: Air conditioning control device for vehicles.   The vehicular air conditioning control device according to any one of claims 1 to 4, wherein the evaporator has a cold storage function of storing heat of the refrigerant.

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