JP4222201B2 - Electronic control device for vehicle air conditioner - Google Patents

Description

  The present invention relates to an electronic control device for a vehicle air conditioner including a computer that executes a vehicle air conditioning computer program.

  Conventionally, as this type of electronic control device, a microcomputer that executes a computer program for air conditioning of a vehicle interior, and an air conditioning constant (for example, calculation of a target outlet temperature) necessary for execution of the computer program for air conditioning of the vehicle interior by the microcomputer are used. A device including a nonvolatile memory (for example, EEPROM) for storing a coefficient to be used has been proposed (for example, see Patent Document 1).

In this device, the microcomputer reads the air conditioning constant from the nonvolatile memory and executes the vehicle interior air conditioning computer program using the read air conditioning constant. Accordingly, the operation of various doors provided in the air conditioning unit is controlled.
JP 2002-67834 A

  By the way, in recent years, as an electronic control device for a vehicle air conditioner, it has been strongly demanded to develop and design in a short period of time while suppressing an increase in cost. There is no description about developing and designing an electronic control device in a short period of time. Therefore, the present inventor examined the development and design of an electronic control device in a short period of time while suppressing an increase in cost by using a nonvolatile memory, and found that the following problems occur.

  That is, the nonvolatile memory itself is more expensive than the mask ROM. Therefore, if the amount of data stored in the nonvolatile memory is increased, it is necessary to increase the capacity of the nonvolatile memory, resulting in an increase in cost. Therefore, it is necessary to reduce the amount of data stored in the nonvolatile memory.

  Therefore, when using a mask ROM instead of a nonvolatile memory as a storage means for storing the air conditioning constant, it is possible to suppress an increase in cost, but in manufacturing a mask ROM, compared to manufacturing a nonvolatile memory, Need a long time. Therefore, in order to perform development design in a limited short period of time, it is necessary to determine the air conditioning constant at an early stage of development design (that is, a stage far behind the end of development design). .

  However, in actuality, a prototype vehicle is required to determine the air conditioning constant. At present, the prototype vehicle cannot be obtained at an early stage of development and design, making it impossible to determine the air conditioning constant at an early stage of development and design. ing. For this reason, it is impossible to use a mask ROM as a storage means for storing the air conditioning constant.

  Therefore, in view of the above points, the present invention provides an electronic control device for a vehicle air conditioner that can cope with a short development period while suppressing an increase in cost by using both a read-only memory and a nonvolatile memory. With the goal.

  The present invention is made by paying attention to the fact that it is impossible to determine the air conditioning constant at an early stage of development and design, but it is possible to determine a plurality of candidate values for the air conditioning constant.

Specifically, in the electronic control device for a vehicle air conditioner according to the first aspect of the present invention, an arithmetic processing unit (251) that executes a computer program for air conditioning the vehicle interior;
A plurality of candidate values in the air conditioning constant necessary for execution of the computer program are stored in association with selection numbers having a data amount smaller than these candidate values, respectively, and the arithmetic processing unit sets the plurality of candidate values. A read only memory (252) configured to be readable and not rewriteable of the plurality of candidate values;
A non-volatile memory (25b) that maintains a memory of a selection number corresponding to a predetermined candidate value among the plurality of candidate values even when power is not supplied,
The arithmetic processing units (S10 to S13, S154) read candidate values corresponding to selection numbers stored in the nonvolatile memory from the read-only memory, and use the read candidate values as the air conditioning constants. The computer program is executed.

  According to the first aspect of the present invention, by storing a plurality of candidate values in association with the selection numbers in the read-only memory, only the selection number corresponding to the predetermined candidate value is nonvolatile. The computer program can be executed using the candidate value corresponding to the stored selection number simply by storing it in the memory.

  Here, since the selection number has a data amount smaller than the candidate value, the air conditioning constant is stored in the nonvolatile memory as it is by storing the selection number corresponding to the predetermined candidate value in the nonvolatile memory. The amount of data stored in the nonvolatile memory can be suppressed as compared with the case where the data is stored. For this reason, an increase in the capacity of the nonvolatile memory can be suppressed, and an increase in cost can be suppressed.

  Further, as described above, it is impossible to determine the air conditioning constant at an early stage of development and design, but it is possible to determine a plurality of candidate values for the air conditioning constant. Therefore, as in the first aspect of the invention, the read-only memory starts storing the read-only memory at an early stage of development design by storing a plurality of candidate values instead of the air conditioning constant. Therefore, it becomes possible to cope with a short development period of the electronic control device.

  In the invention according to claim 2, when the arithmetic processing unit (S11, S14) determines that the non-volatile memory has failed and an accurate selection number cannot be read from the non-volatile memory, the arithmetic processing unit (S11, S14) A predetermined candidate value is read from the plurality of candidate values stored in the read-only memory, and the computer program is executed using the read candidate value as the air conditioning constant. .

  As a result, even when the nonvolatile memory fails, it is possible to prevent the computer program from being disabled by executing the computer program using a predetermined candidate value.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

  FIG. 1 is a schematic diagram of the overall configuration of a vehicle air conditioner to which an electronic control device of the present invention is applied. The indoor unit of the vehicle air conditioner is roughly divided into a blower unit 1 and an air conditioning unit 2. Is done.

  The blower unit 1 includes an inside / outside air switching box 3 and a blower 4. The inside / outside air switching door 5 in the inside / outside air switching box 3 opens and closes the outside air introduction port 6 and the inside air introduction port 7. Thereby, outside air (vehicle compartment outside air) or inside air (vehicle compartment air) is switched and introduced into the inside / outside air switching box 3. The inside / outside air switching door 5 is driven by an electric drive device 8 comprising a servo motor. The blower 4 is provided with a centrifugal blower fan 9 and a driving motor 10.

  The air conditioning unit 2 is provided with an air conditioning case 2a that forms an air passage. An evaporator (cooling heat exchange means) 11 that constitutes a refrigeration cycle is disposed upstream of the air conditioning case 2a. On the side, an air mix door 12 is arranged. On the downstream side of the air mix door 12, a hot water heater core (heating heat exchanging means) 13 that heats the air using hot water (cooling water) of the vehicle engine as a heat source is installed. A bypass passage 14 that bypasses the hot water heater core 13 and flows air is formed on the side (upper portion) of the hot water heater core 13.

  The air mix door 12 is a rotatable plate-like door, and is driven by an electric drive device 15 composed of a servo motor. The air mix door 12 adjusts the air volume ratio between the hot air passing through the hot water heater core 13 and the cool air passing through the bypass passage 14, and the air blown into the vehicle interior by adjusting the air volume ratio of the cold / hot air. Adjust the temperature. Therefore, in this example, the air mix door 12 constitutes a temperature adjusting means for the air blown into the vehicle interior.

  A hot air passage 16 extending from the lower side to the upper side is formed on the downstream side of the hot water heater core 13. The hot air from the hot air passage 16 and the cold air from the bypass passage 14 are mixed by the air mixing unit 17 to be desired. Can produce temperature air.

  Further, an air outlet mode switching unit is configured on the downstream side of the air mixing unit 17 in the air conditioning case 2a. That is, a defroster opening 18 is formed on the upper surface of the air conditioning case 2a, and this defroster opening 18 blows air to the inner surface of the vehicle windshield through a defroster duct (not shown). The defroster opening 18 is opened and closed by a rotatable plate-like defroster door 19.

  In addition, a face opening 20 is formed on the upper surface of the air-conditioning case 2a at the rear side of the vehicle from the defroster opening 18, and the face opening 20 is directed toward the upper body of the passenger in the vehicle cabin via a face duct (not shown). It blows out air. The face opening 20 is opened and closed by a rotatable plate-like face door 21.

  Further, in the air conditioning case 2a, a foot opening 22 is formed in a lower part of the face opening 20, and air is blown out from the foot opening 22 toward the feet of passengers in the passenger compartment. The foot opening 22 is opened and closed by a rotatable plate-like foot door 23.

  The blow-out mode doors 19, 21, and 23 are connected to a common link mechanism (not shown), and are driven by an electric drive unit 24 including a servo motor via the link mechanism.

  Next, the outline of the electric control unit in the present embodiment will be described. The electronic control device 25 includes a well-known microcomputer 25a including a CPU 251, a ROM (mask ROM) 252, a RAM (not shown), and an EEPROM (nonvolatile). Memory) 25b and peripheral circuits.

  Here, the ROM 252 is a read-only memory configured such that a plurality of candidate values can be read by the CPU 251 and the plurality of candidate values cannot be rewritten, and four types of air conditioning constants A, B, In order to determine C and D, a comparison table is stored as shown in FIG. In this comparison table, a plurality of candidate values (0, -14, -12, -10..., 12, 14) of the air conditioning constants A, B, C, and D are stored, and the plurality of candidates are selected. Numbers (0, 1, 2, 3, 4,... 14) are associated with each other.

  Here, 4-bit data is used as the selection number, and 15 selection numbers are set for each of the air conditioning constants A, B, C, and D. As a plurality of candidate values for each of the air conditioning constants A, B, C, and D, 8-bit data is used.

  Each of the four types of air conditioning constants A, B, C, and D is used to calculate a correction constant Cz in a calculation formula for the target blowout temperature TAO, as will be described later, and the air conditioning constants A, B, C, and D are used. A method for calculating the correction constant Cz and thus the target blowing temperature TAO will be described later.

  The EEPROM 25b is a non-volatile memory that maintains data storage even when power is not supplied. The EEPROM 25b contains not only the RAM save data but also a predetermined candidate value among a plurality of candidate values. Corresponding selection numbers are stored.

  The saved data in the RAM is data moved from the RAM when the ignition switch is turned off. The RAM stores data associated with the execution of the computer program by the CPU 251.

  On the other hand, a temperature sensor 26 composed of a thermistor is provided as a temperature sensor of the evaporator 11, and this temperature sensor 26 is disposed in the air-conditioning case 2a immediately after the air is blown out of the evaporator 11, and the evaporator blowing temperature Te. Is detected.

  In addition to the temperature sensor 26 described above, the electronic control unit 25 has detection signals from well-known sensors 27 to 30 that detect the internal air temperature Tr, the external air temperature Tam, the solar radiation amount Ts, the hot water temperature Tw, and the like for air conditioning control. Is entered. Note that the inside air sensor 27 that detects the inside air temperature Tr is disposed, for example, at a lower portion (near the center cluster) of the central part in the left-right direction of the vehicle interior instrument panel, and the representative temperature inside the vehicle interior is defined as the inside air temperature Tr. To detect.

  The air conditioning control panel 31 installed in the vicinity of the vehicle interior instrument panel is provided with operation switches 32 to 36 that are manually operated by passengers, and operation signals of the operation switches 32 to 36 are also input to the electronic control unit 25. .

  Specifically, as the operation switch, a temperature setting switch 32 that generates a temperature setting signal Tset, an air volume switch 33 that generates an air volume switching signal, an air outlet mode switch 34 that generates an air blowing mode signal, and an inside / outside air switching signal are generated. An inside / outside air changeover switch 35, an air conditioner switch 36 for intermittently operating the compressor (not shown) of the refrigeration cycle, and the like are provided.

  Next, the operation of this embodiment in the above configuration will be described. The flowchart of FIG. 3 shows the control processing executed by the CPU 251 of the microcomputer 25a of the electronic control device 25, and the flowchart of FIG. 4 shows a part of the control processing of FIG.

  The CPU 251 is activated when an ignition switch of a vehicle engine (not shown) is turned on and power is supplied to the control device 25. Accordingly, the CPU 251 starts execution of the computer program according to the flowchart of FIG.

  First, in step S9, flags, timers, and the like are initialized. When the process proceeds to step S10, the selection numbers of the air conditioning constants A, B, C, and D are read from the EEPROM 25b.

  Here, an error determination code such as a CRC check code is added in advance to each selection number of the air conditioning constants A, B, C, and D, and in step 11, an error added to each selection number. Based on the determination code, it is determined whether each of the four selection numbers is a normal value.

  Then, when all the selection numbers of the air conditioning constants A, B, C, and D are normal values, it is determined as YES. That is, the selection numbers of the air conditioning constants A, B, C, and D are not garbled, and it is determined that the EEPROM 25b is normal.

  In this case, it is determined that each value as the selection number of each of the air conditioning constants A, B, C, and D read from the EEPROM 25b is formally used as the selection number, and a comparison table (FIG. 2) stored in the ROM 252. The candidates of the air conditioning constants A, B, C, and D corresponding to the selection numbers are read out from the reference), and the candidates are determined to be used as the air conditioning constants A, B, C, and D, respectively.

  On the other hand, if it is determined in step 11 that one of the four selection numbers is an abnormal value, NO is determined. That is, it is determined that any one of the selection numbers of the air conditioning constants A, B, C, and D is garbled.

  In this case, the respective candidate numbers for the predetermined air conditioning constants A, B, C, and D are read from the ROM 252 without using the selection numbers read from the EEPROM 25b. In this case, for example, the candidate value (14) corresponding to the 15th selection number 14 is used as each candidate value of the air conditioning constants A, B, C, and D.

  As described above, when the respective candidate values of the air conditioning constants A, B, C, and D are determined, the process proceeds to step S15 and air conditioning control processing is performed. Specifically, in step S152 of the flowchart shown in FIG. 4, the operation signals of the operation switches 32-36 of the air conditioning control panel 31 are read. In the next step S153, a vehicle environmental state signal, that is, a detection signal from the sensors 26 to 30 is read.

  Subsequently, in step S154, a target blowing temperature TAO of the conditioned air blown into the vehicle interior is calculated. This target blowing temperature TAO is a blowing temperature necessary for maintaining the passenger compartment at the set temperature Tset of the temperature setting switch 32, and is calculated based on the following Equation 1.

TAO = Kset × Tset−Kr × Tr
−Kam × Tam−Ks × Ts + C (Equation 1)
However, Tr: The inside air temperature detected by the inside air sensor 27 Tam: The outside air temperature detected by the outside air sensor 28 Ts: The amount of solar radiation detected by the solar sensor 29 Kset, Kr, Kam, Ks: Control gain Cz: Correction constant The calculation of the correction constant Cz in the calculation formula (Formula 1) for the target outlet temperature TAO will be described later.

  Next, in step S155, a target air flow rate of air blown by the blower 4, specifically, a blower voltage level that is an applied voltage of the blower driving motor 10 is determined based on the TAO. As is well known, the blower voltage level is increased by increasing the blower voltage level on the high temperature side (maximum heating side) and low temperature side (maximum cooling side) of the TAO to obtain the maximum air volume (Hi), and the intermediate temperature of the TAO. Decrease the blower voltage level in the area to the minimum air volume (Lo).

  Here, the blower voltage level changes in multiple stages (for example, 31 stages) according to TAO in order to control the air volume in multiple stages between the maximum air volume (HI) and the minimum air volume (LO). ing.

  Next, in step S156, the inside / outside air mode is determined. In this inside / outside air mode, for example, the inside air mode is set when the inside temperature Tr is significantly higher than the set temperature Tset by a predetermined temperature or higher (during cooling high load), and the outside air mode is set at other times. Alternatively, as the TAO rises from the low temperature side to the high temperature side, the setting may be switched from the all-inside air mode → the inside / outside air mixing mode → the all outside air mode.

  Next, in step S157, the blowing mode is determined according to the TAO. As is well known, the blowing mode is switched from face mode to bi-level mode to foot mode as TAO rises from the low temperature side to the high temperature side.

  Next, in step S158, the target opening degree SW of the air mix door 12 is calculated by the following formula 2 based on the TAO, the evaporator outlet temperature Te, and the hot water temperature Tw.

SW = [(TAO−Te) / (Tw−Te)] × 100 (%) (Equation 2)
Here, the target opening degree SW of the air mix door 12 sets the maximum cooling position of the air mix door 12 (solid line position in FIG. 1) to 0%, and the maximum heating position of the air mix door 12 (dotted line position in FIG. 1). Is expressed as a percentage with 100%.

  Next, the process proceeds to step S159, where the actual evaporator outlet temperature Te detected by the temperature sensor 26 is compared with the target evaporator temperature TEO determined based on the TAO or the like, and an air conditioner compressor (not shown) is compared. The applied voltage to the electromagnetic clutch is determined, and the intermittent operation (ON-OFF) of the compressor operation is determined.

  Next, it progresses to step S160 and a control signal is output to various actuator parts (8, 10, 15, 24, etc.) so that the control state determined by said step S155-S159 may be obtained. In the next step S161, the process waits for the control period τ, and when it is determined that the control period τ has elapsed, the process returns to step S152. As a result, the passenger compartment is automatically air-conditioned.

  Hereinafter, calculation of the correction constant Cz in the calculation formula (Formula 1) of the target blowout temperature TAO will be described.

  That is, a different value is used as the correction constant Cz depending on the outside air temperature Tam. For example, as shown in FIG. 5, the correction constant Cz is corrected from the characteristic graph in which the horizontal axis is the outside air temperature Tam and the vertical axis is the correction constant Cz. A constant Cz is determined. Here, the air conditioning constants A, B, C, and D determined as described above are used to obtain a characteristic graph as follows.

  That is, in a two-dimensional coordinate system in which the horizontal axis is the outside air temperature Tam and the vertical axis is the correction constant Cz, the air conditioning constant A as the value of the correction constant Cz when the outside air temperature Tam is equal to or lower than “−10 ° C.”. The air conditioning constant B is used as the value of the correction constant Cz when the outside air temperature Tam is “0 ° C.”. Further, the air conditioning constant Cz is used as the value of the correction constant Cz when the outside air temperature Tam is “+ 10 ° C.”, and the air conditioning is performed as the value of the correction constant Cz when the outside air temperature Tam is equal to or higher than “+ 20 ° C.”. The constant D is used.

  The characteristic point (●) when the outside air temperature Tam is “−10 ° C.” and the characteristic point (●) when the outside air temperature Tam is “0 ° C.” are connected by a straight line. ”And the characteristic point (●) when the outside air temperature Tam is“ 10 ° C. ”and the characteristic point (●) when the outside air temperature Tam is“ 10 ° C. ” The characteristic point (●) when the outside air temperature Tam is “20 ° C.” is connected with a straight line.

Thus, the characteristic graph is obtained, and the correction constant Cz is obtained from the obtained characteristic graph and the outside air temperature Tam. In the example shown in FIG. 5, characteristic graphs obtained when selection numbers NO6, NO4, NO9, and NO11 are set for the air conditioning constants A, B, C, and D are shown.
Next, the effect of this embodiment is demonstrated. That is, in the electronic control device of the present embodiment, the CPU 251 that executes the computer program for air conditioning in the vehicle interior, and each of a plurality of candidate values in the air conditioning constants A, B, C, and D necessary for the execution of the computer program are selected. A ROM 252 that stores the number in association with the number and an EEPROM 25b that maintains the storage of the selection numbers of the air conditioning constants A, B, C, and D are provided.
Here, the CPU 251 reads candidate values corresponding to each selection number stored in the EEPROM 25b from the read-only memory 25b, and uses each of the read candidate values as the air conditioning constants A, B, C, and D. Run a computer program.

  Here, since the selection number is 4-bit data and has a data amount smaller than the 8-bit data candidate value, the EEPROM 25b stores the selection number corresponding to the predetermined candidate value in the EEPROM 25b. The amount of data stored in the EEPROM 25b can be suppressed as compared with the case where the air conditioning constant is stored as it is. For this reason, an increase in the capacity of the EEPROM 25b can be suppressed, and an increase in cost can be suppressed.

  Further, as described above, it is impossible to determine the air conditioning constant at an early stage of development and design of the electronic control device, but it is possible to determine a plurality of candidate values for the air conditioning constant. Therefore, in the present embodiment, by storing a plurality of candidate values instead of the air conditioning constant in the ROM 252, it becomes possible to start manufacturing the ROM 252 at an early stage of development design. It becomes possible to cope with a short development period.

In the present embodiment, when the CPU 251 determines that the EEPROM 25b has failed and an accurate selection number cannot be read from the EEPROM 25b,
Of the candidate values for the air conditioning constants A, B, C, and D, candidate values for each predetermined air conditioning constant are read from the ROM 252 and the computer program is executed using the read candidate values.

  Thereby, even when the EEPROM 25b breaks down, the CPU 251 executes the computer program using the candidate value for each predetermined air conditioning constant, so that the execution of the computer program can be avoided.

In this embodiment, 4-bit data is used, and 15 selection numbers (0 to 14) are set for each of the air conditioning constants A, B, C, and D. For this reason, even when the selection number is garbled and it is determined in the correctness determination process (S11) that the selection number is a correct value, the garbled selection number is any of 0-14. There is a high possibility of becoming.
For this reason, even if the selection number is garbled, an air conditioning constant corresponding to any value among 0 to 14 is selected, so that a value far from each candidate value is not selected. Therefore, even if the selection number is garbled, it can be avoided that the computer program cannot be executed.

(Other embodiments)
In the above-described embodiment, the example in which the microcomputer 25 is employed and the CPU 251 executes the computer program has been described. However, the present invention is not limited to this, and various CPUs such as a DSP are employed and the CPU 251 is replaced with the computer program. May be executed.

  In the above-described embodiment, an example in which 4-bit data is used as a selection number has been described. It may be.

1 is a schematic diagram showing an overall configuration of a vehicle air conditioner according to an embodiment of the present invention. It is a graph which shows the comparison table for determining the air-conditioning constant of the vehicle air conditioner which concerns on the above-mentioned embodiment. It is a flowchart which shows the control processing of the electronic controller of FIG. It is a flowchart which shows the one part control processing in FIG. 3 in detail. It is a figure which shows the characteristic graph for determining the air-conditioning constant of the vehicle air conditioner which concerns on the above-mentioned embodiment.

Explanation of symbols

25 ... Electronic control unit, 251 ... CPU, 252 ... ROM,
A, B, C, D: Air conditioning constant, 25b: EEPROM.

Claims (2)

An arithmetic processing unit (251) for executing a computer program for air conditioning the vehicle interior;
A plurality of candidate values in the air conditioning constant necessary for execution of the computer program are stored in association with selection numbers having a data amount smaller than these candidate values, respectively, and the arithmetic processing unit sets the plurality of candidate values. A read only memory (252) configured to be readable and not rewriteable of the plurality of candidate values;
A non-volatile memory (25b) that maintains a memory of a selection number corresponding to a predetermined candidate value among the plurality of candidate values even when power is not supplied,
The arithmetic processing units (S10 to S13, S154) read candidate values corresponding to selection numbers stored in the nonvolatile memory from the read-only memory, and use the read candidate values as the air conditioning constants. An electronic control unit for a vehicle air conditioner, wherein the computer program is executed. When the arithmetic processing unit (S11, S14) determines that the nonvolatile memory fails and an accurate selection number cannot be read from the nonvolatile memory, the arithmetic processing units (S11, S14) store the plurality of data stored in the read-only memory. 2. The vehicle air conditioning according to claim 1, wherein among the candidate values, a predetermined candidate value is read, and the computer program is executed using the read candidate value as the air conditioning constant. Electronic control device of the device.

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