JP2006327226A - Air-conditioner for vehicle and air-conditioning method of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air-conditioner for a vehicle allowing use of a heater able to warm inside a cabin sufficiently while balancing is well taken with the load of an electric power supply for the vehicle. <P>SOLUTION: The air-conditioner 30 for the vehicle includes a PTC heater fed with current from a 12-V battery 18 as the power supply for the vehicle and warming inside the cabin and an ECU 32 etc. for air-conditioning. A current feed determining part 34 determines whether the PTC heater 50 should be fed with current or not on the basis of signals given by a warming switch 44 and a water temperature sensing means 22 for engine cooling water, while a load determining means determines whether the power supply for the vehicle is an overloaded condition based on the context of a signal line 48 from a DC/DC converter 16, and a current feed controlling means performs an intermittent current feed control using a current feed On/Off ratio with which the temperature of the PTC heater 50 can rise, in case there is necessity for feeding the current to the PTC heater 50 and the power supply for the vehicle is overloaded. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle air conditioning apparatus and a vehicle air conditioning method, and more particularly to a vehicle air conditioning apparatus and a vehicle air conditioning method for warming a vehicle interior of a vehicle.

  When the vehicle interior of the vehicle is cold, the driver turns on a warm-up switch such as a heater switch provided on the panel to introduce air warmed by the engine into the vehicle interior. In extremely cold regions and in cold weather, it takes time for the engine to sufficiently warm the air for blowing, and cold air may come out for a while. Therefore, an auxiliary heater or the like is used. For example, in Patent Literature 1, in a vehicle air conditioner, the number of energizations of heating element elements such as three PTC elements is finely controlled according to the outside air temperature and the cooling water temperature from the vehicle engine, thereby reducing wasteful power consumption. It is stated to prevent. In addition, it is also described that the number of energizations of the heating element is determined according to the state of charge of the in-vehicle battery and energization is performed within the range of the number.

  Here, the PTC element is an element having a positive resistance temperature characteristic in which the resistance value rapidly increases at a predetermined curie point, and is a semiconductor element having a self-temperature control function for self-controlling the heat generation temperature at the curie point. As such a PTC element, for example, a barium titanate ceramic having a Curie point of about 150 ° C., which is made into a semiconductor by adding a small amount of rare earth elements such as yttrium, antimony, and lanthanum can be used.

  By the way, the auxiliary heater including the PTC heater consumes a considerable amount of electric power and lowers the voltage of the vehicle power source. Since the power source for the vehicle is used not only for the auxiliary heater but also for electric devices mounted on the vehicle, the consumption amount of the power source for the vehicle is large, and if the voltage is too low, the operation of these devices is hindered. Therefore, it is necessary to limit the use of the auxiliary heater depending on the load state of the vehicle power supply.

  For example, Patent Document 2 discloses that in an air conditioning unit of a hybrid vehicle, the cooling water of a traveling engine is used as a heat source for heating, and two PTC heaters are used as auxiliary electric heaters. Here, based on the judgment of the heating requirement in the passenger compartment, the judgment of the water temperature of the heating heat source, the judgment of the current capacity margin of the DC-DC converter for the vehicle power supply, etc., all the PTC heaters are turned off when there is no margin. Is stated. The current capacity margin of the DC-DC converter is determined based on whether or not a current exceeding the charging capacity of the DC-DC converter is used in the entire hybrid vehicle. In addition, it is stated that the PTC heater is turned on and off at a predetermined time, for example, 16 seconds after the previous on and off so as not to be frequent.

Japanese Patent Laid-Open No. 11-42936 Japanese Patent Laid-Open No. 11-115469

  In the prior art, the use of the vehicle interior warming heater increases the load of the vehicle power supply, and therefore, when the vehicle power supply is not sufficient, as in Patent Document 1, energization is continued while limiting the number of heaters. Alternatively, as in Patent Document 2, a measure is taken to turn off all the heaters.

  However, once it is determined that warming is necessary and energization of the heater is started, if energization of some or all of the heaters is stopped due to a problem with the load of the power supply for the vehicle, the warming air conditioning is interrupted. It is not preferable. Therefore, in practice, once the heater is energized, the energization is continued for a predetermined time during which the heater can sufficiently warm up, and then the heater is turned off. In this case, since the vehicular power supply is overloaded during the energization, it is preferable that power saving of a device that is not related to vehicle running, such as a radio, among other on-vehicle electric devices is performed. . In addition, devices that receive power from the vehicle power supply and have an impact on the vehicle's travel, etc., issue a warning (alarm signal) when the vehicle power supply voltage drops below a predetermined value, paying attention to the operation. It is preferable to prompt.

  As described above, in the prior art, it is not easy to balance the use of the heater used for warming the passenger compartment of the vehicle and the load of the power source for the vehicle. In some cases, the use of the heater generates an alarm signal. This could cause problems with the operation of the vehicle.

  An object of the present invention is to provide a vehicle air conditioner that enables use of a heater capable of sufficiently warming up a vehicle interior while balancing the load of a vehicle power source. Another object of the present invention is to provide a vehicle air conditioner that enables use of a heater that balances the load of the vehicle power supply and that can sufficiently warm the passenger compartment without outputting an alarm signal. Is to provide. The following means serve at least one of the above purposes.

  An air conditioner for a vehicle according to the present invention is energized by a power source mounted on the vehicle and heats the vehicle interior of the vehicle, and controls the energization of the heat generator based on the load state of the power source to control the air in the vehicle interior. An air conditioning apparatus for a vehicle including a control unit that performs harmony, wherein the control unit determines whether or not the heating element needs to be energized in order to warm up the vehicle interior, Load determination means for determining whether or not the load state is overload, and energization on / off that can increase the temperature of the heating element when it is necessary to energize the heating element and the power supply is overloaded And an energization control means for performing intermittent energization control using the ratio.

  In addition, the control unit includes an output unit that outputs an alarm signal when the period during which the power supply voltage falls below a predetermined threshold exceeds an arbitrarily determined determination period, and the energization control unit is shorter than the determination period for the alarm signal. It is preferable that the energization is interrupted using the energization on time.

  Further, the energization control means preferably performs energization interruption using an energization off time sufficient for the power supply voltage to recover beyond a predetermined threshold.

  The vehicle air conditioning method according to the present invention includes a heating element that is energized by a power source mounted in the vehicle and warms the passenger compartment of the vehicle, and controls the energization of the heating element based on a load state of the power source. And an air conditioning method executed on a vehicle air conditioner including a control unit for performing air conditioning, wherein energization is performed to determine whether the heating element needs to be energized in order to warm the vehicle interior The determination process, the load determination process for determining whether the load state of the power supply is overloaded, and the temperature of the heating element rises when the heating element needs to be energized and the power supply is overloaded And an energization control step of performing intermittent energization control using an energization on / off ratio that can be applied.

  According to the above configuration, since it is necessary to energize the heating element and the power supply is overloaded, intermittent energization control is performed using an energization on / off ratio that can increase the temperature of the heating element. When the vehicle is off, no load is applied to the vehicle power supply, and the temperature of the heating element can be raised as a whole to sufficiently warm the vehicle interior.

  In addition, since energization is interrupted using an energization on time shorter than the judgment period for the alarm signal, even if the power supply voltage temporarily decreases due to energization of the heating element when intermittent energization is on, the alarm signal Does not affect judgment. Therefore, the alarm signal is not output while the temperature of the heating element is raised as a whole to sufficiently warm the passenger compartment.

  Further, since the energization is interrupted using the energization off time sufficient for the power supply voltage to recover beyond the predetermined threshold, the power supply voltage can be sufficiently recovered when the intermittent energization is turned off.

  As described above, according to the vehicle air conditioning apparatus and the vehicle air conditioning method of the present invention, the use of the heater that can sufficiently warm the vehicle interior while balancing with the load of the vehicle power supply. Is possible. In addition, it is possible to use a heater that balances the load of the vehicle power supply and can sufficiently warm the vehicle interior without outputting an alarm signal.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. In the following, there will be described a case where a high-voltage power source is provided as in a hybrid vehicle, this is adjusted by a DC / DC converter and stored in a 12V battery, and this 12V battery is used as a so-called vehicle power source. It may be a power system. For example, a rechargeable secondary battery may be used as a vehicle power source. Further, as various loads connected to the vehicle power source, a PTC heater, two ECUs (Electric Control Unit), a radio, a fan, and the like will be described, but these are examples. In addition, a general device such as a lamp, a device that uses a warning (alarm output) associated with a decrease in power supply voltage, such as an ECU for power steering, or the like may be used as a load. Further, although a PTC heater will be described as a heater for warming the passenger compartment, other warming means such as an electric heater may be used.

  FIG. 1 is a block diagram of a vehicle air conditioner 30 in a hybrid vehicle, which is not a component of the vehicle air conditioner 30, but includes a vehicle power supply system 10, various on-vehicle electric devices 20, a water temperature sensor. The engine cooling water temperature detecting means 22 such as the above, and an in-panel alarm display section 24 for displaying an alarm for a drop in the power supply for the vehicle are shown.

  The vehicle power supply system 10 is a system that supplies power to various devices mounted on the vehicle. The vehicle power supply system 10 includes, for example, an HV high-voltage battery 12 that stores 300V high-voltage power, a system main relay (SMR) 14 for cutting off reception of high-voltage power, and a DC / DC converter that converts 300V DC high voltage to 12V power. 16, It is comprised including the 12V battery 18 which stores the converted 12V electric power.

  The HV high-voltage battery 12 is connected to a regenerative generator via circuit means such as an inverter, and stores regenerative electric energy when the vehicle is regenerated. Further, it is connected to a driving motor and supplies electric power for driving the vehicle. The regenerative generator and the driving motor can be used as a so-called electric / generator.

  The 12V battery corresponds to a vehicle power source in a narrow sense here, and is a chargeable / dischargeable secondary battery having a function of supplying power to various on-vehicle devices. This power supply line is also an output line of the DC / DC converter 16 and is indicated by a thick power line 46 in FIG. Many electric devices mounted on the vehicle are connected to the power supply line 46. In FIG. 1, a PTC heater 50, an energization control relay 52, which will be described later, an air conditioning ECU (A / C-ECU) 32, and a brake ECU. In addition to (Electric Control Break ECU: ECB-ECU) 40, an electric device 20 such as a radio or a fan is shown.

  Here, the vehicle air conditioner 30 includes the air conditioner ECU 32, the brake ECU 40, the warm air switch 44, the PTC heater 50, and the relay 52 operated by a driver or the like. In addition, the air conditioning ECU 32 and the brake ECU 40 have a function as a control unit that controls the overall operation of the vehicle air conditioning apparatus 30.

  The air conditioning ECU 32 controls the energization of the PTC heater 50 via the relay 52 based on the input signals from the DC / DC converter 16, the warm air switch 44, and the engine coolant water temperature detecting means 22, and achieves air conditioning. Have

  Here, the signal line 48 from the DC / DC converter 16 transmits a signal indicating the load state of the DC / DC converter 16. Specifically, the HV high-voltage battery 12 converts a high-voltage power and supplies a signal that can indicate whether or not the load power exceeding the charging capacity for charging the 12V battery 18 is used. This signal indicates that when a load power exceeding the charging capacity is used, the so-called overload prohibits further power consumption, and only a load power less than the charging capacity is used. If not, there is still room and results in permitting further power consumption, which can be referred to as a “prohibit / permit signal”. Specifically, an appropriate signal indicating the operating characteristics of the DC / DC converter 16 can be used. For example, a signal related to the magnitude of the discharge current or a signal corresponding thereto can be used. The “prohibition / permission signal” may be a continuous value indicating a load state, or the continuous value may be binarized such that prohibition = 1 and permission = 0 by using a threshold value or the like.

  The warm-up switch 44 is an operation switch provided in the vehicle interior of the vehicle, and is a switch that is turned on when the temperature of the vehicle interior is low and a driver or the like tries to warm up the vehicle interior. The warm-up switch 44 can designate the degree of warm-up by setting the switch according to the distinction such as “MAX-HOT”, “MID-HOT”, “LOW-HOT”, and the like. The designations such as “MID-HOT” and “LOW-HOT” are set so that warm air using the engine is sufficient. Further, when “MAX-HOT” is specified, it is set that the engine warm-up is insufficient and the PTC heater 50 needs to be warmed up. The content of the operation of the warm air switch 44 is converted into an electric signal and output to the air conditioning ECU 32.

  The engine cooling water temperature detection means 22 has a function of detecting the temperature of the engine cooling water and outputting the detected temperature to the air conditioning ECU 32. Here, the engine cooling water is used to warm the air supplied to the passenger compartment by obtaining heat by cooling the high-temperature engine and flowing through a heat exchanger (not shown). The engine coolant temperature detection means 22 has a sufficiently high coolant temperature so that the vehicle interior can be sufficiently warmed only by heat exchange of the engine coolant without using the PTC heater 50, or the coolant temperature is A signal indicating whether the PTC heater 50 needs to be used to sufficiently warm the passenger compartment is output to the air conditioning ECU 32. The signal output to the air conditioning ECU 32 may be a continuous value indicating the water temperature state, or a binary value such as PTC heater unnecessary = 0 and PTC heater required = 1 by using the continuous value as a threshold value or the like. May be used. The determination of whether or not the PTC heater 50 needs to be energized can be made with a water temperature of 65 ° C. as a guide, for example. That is, when the water temperature is 65 ° C. or less, the PTC 50 can be energized.

  As is well known, the PTC heater 50 is a heating element having a positive resistance temperature characteristic in which a resistance value rapidly increases at a predetermined curie point, and a semiconductor element having a self-temperature control function that self-controls the exothermic temperature to the curie point. It is. As such a PTC element, a barium titanate-based ceramic having a Curie point of about 150 ° C., which is made into a semiconductor by adding a small amount of a rare earth element such as yttrium, antimony, or lanthanum, can be used. In this case, the PTC heater 50 is heated when energized, and the temperature is kept constant at about 150 ° C. The PTC heater 50 is connected in series with the relay 52 between the 12V power line 46 and the ground, and the energization of the PTC heater 50 is controlled by opening and closing the relay 52.

  The ECB-ECU 40 is a control circuit that electrically controls the braking operation of the vehicle. In relation to the air conditioning ECU 32, an alarm output unit 42 is provided. The alarm output unit 42 has a function of outputting a warning (alarm signal) that warns about the brake operation when the power supply voltage of the 12V power supply line 46 falls below a predetermined value. Specifically, a power supply voltage drop is detected with a predetermined threshold, and an alarm signal is output when a period below the threshold continues beyond a predetermined determination period. Based on the output alarm signal, a predetermined alarm mark is displayed on the in-panel alarm display section 24 in the vehicle compartment. As a method for displaying that an alarm signal has been output, an alarm sound may be used in addition to an image, an alarm sound, or a combination thereof may be displayed.

  The air conditioning ECU 32 has a function of opening / closing the relay 52 and controlling the energization of the PTC heater 50 based on input signals from the DC / DC converter 16, the warm air switch 44, and the coolant temperature detection means 22. Circuit. The control sufficiently warms the interior of the vehicle when necessary, so that the warning output unit 42 of the ECB-ECU 40 determines that the power supply voltage of the power supply line 46 is too low and does not issue a warning (warning signal). Done.

  The air conditioning ECU 32 determines whether or not the PTC heater 50 needs to be energized to warm up the vehicle interior based on a signal from the warm air switch 44 and a signal from the engine coolant water temperature detecting means 22. It is necessary to energize the determination unit 34, the load determination unit 36 that determines whether or not the load state of the vehicle power source is overloaded based on the signal from the DC / DC converter 16, and the PTC heater 50. An energization control unit 38 that controls energization of the PTC heater 50 when the power source is overloaded. These functions can be realized by software, specifically, by executing a corresponding air conditioning program. Moreover, you may comprise so that a part of each function may be implement | achieved by hardware.

  The operation of the vehicle air conditioner 30 having the above configuration, particularly each function of the air conditioner ECU 32, will be described with reference to the flowchart of FIG. The procedure of the vehicle air conditioning method shown in FIG. 2 also shows each step of the air conditioning program.

  In order to perform air conditioning of the vehicle, first, each element of the vehicle air conditioning device 30 is initialized. Then, it is determined whether or not the warm-up switch is “MAX-HOT” (S10). Specifically, the function of the energization determination unit 34 determines whether the selection is “MAX-HOT” based on the signal from the warm-up switch 44. That is, if the signal from the warm-up switch 44 indicates “MAX-HOT”, it is considered that the PTC heater 50 needs to be energized. Therefore, it is next determined whether or not the engine coolant temperature is 65 ° C. or less (S12). ) Specifically, the function of the energization determining unit 34 determines whether or not the signal indicates a water temperature of 65 ° C. or less based on the signal from the coolant temperature detection means 22 of the engine cooling water. If the water temperature is 65 ° C. or lower, it is determined that the PTC heater 50 needs to be energized, and the process proceeds to the next S14.

  If it is not determined at S10 that “MAX-HOT” or if the water temperature is not determined to be 65 ° C. or lower at S12, the process proceeds to S18, and in either case, the PTC heater 50 is not energized, The procedure returns to S10 again.

  As described above, whether or not it is necessary to energize the PTC heater 50 that is a heating element to warm up the vehicle interior is determined from the content of the signal from the warm-up switch 44 and the water temperature detection means 22 of the engine coolant. Based on two of the contents of the signal. Specifically, there are two choices, such as “MAX-HOT” that the user desires to warm up the passenger compartment most quickly, and that the engine coolant temperature is lower than a predetermined value. When it is satisfied, it is determined that the PTC heater 50 needs to be energized. When these two signals are signals of continuous values as described above, the meaning of the values may be interpreted by the energization determining unit 34, and these two signals are already “MAX-HOT. ”Or a binary signal indicating whether or not the water temperature is 65 ° C. or less, the meaning of the binary value may be interpreted by the energization determining unit 34. Further, the energization determining unit 34 may determine whether the PTC heater 50 needs to be energized based on other factors. For example, the necessity of energization of the PTC heater 50 may be determined based on the vehicle interior temperature or the like or in combination with the above two conditions.

  If it is determined through S10 and S12 that the PTC 50 needs to be energized, it is next determined whether or not energization is prohibited (S14). This is a determination as to whether or not the “prohibition / permission signal” indicating the load state of the DC / DC converter 16 is a prohibition signal. Specifically, the function of the load determination unit 36 of the air conditioning ECU 32 determines the signal line 48. It is determined whether the content indicates an overload of the vehicle power supply. When the content of the signal on the signal line 48 is a continuous value indicating the load state, the meaning of the value may be interpreted by the load determination unit 36, and the content of the signal already indicates permission or prohibition. When it is a binary signal, the meaning of the binary value may be interpreted by the load determination unit 36.

  If it is determined in S14 that energization is prohibited, normal control, that is, on-control for energizing the PTC heater 50 by closing the relay 52, is performed assuming that the load of the vehicle power supply has a margin (S16). This control is performed by the function of the energization control unit 38 of the air conditioning ECU 32. And as a procedure, it returns to S10 again.

  FIG. 3 is a diagram showing a temperature rise when the PTC heater 50 is energized and a temperature decrease when the energization is stopped. Here, the vertical axis represents the temperature of the PTC heater 50, and the horizontal axis represents time. After energization, the PTC heater 50 aims to reach a predetermined temperature of about 150 ° C. as described above, and continues to increase in temperature. When the saturation temperature is reached at T3 after energization, the self-temperature control function continues energization thereafter. However, it is stable at the saturation temperature. In FIG. 3, the time to rise to the predetermined temperature is shown as T3. The temperature rise time T3 is, for example, about 20 seconds to 25 seconds.

  The PTC heater 50 is used as a heat exchanger, and the air into the passenger compartment is warmed up, thereby air conditioning in the passenger compartment. When the passenger compartment is sufficiently warmed up, a user such as a driver switches the warm-up switch 44 from “MAX-HOT” to another instruction. Then, in S10 where monitoring is continued constantly or with a certain sampling, it is not determined that the determination is “MAX-HOT”, and the process proceeds to S18 where control is performed to turn off the PTC heater 50.

  When the energization is turned off after the PTC heater 50 has been raised to a predetermined temperature of 150 ° C., the temperature of the PTC heater 50 continues to decrease as shown in FIG. Here, the time required for the temperature to return to room temperature again from a predetermined temperature is indicated as T4. The cooling time T4 is, for example, about 5 minutes.

  When it is not determined in S14 that energization is not prohibited, that is, when the vehicle power supply is in an overload state, energization of the PTC heater 50 is kept on or off from normal control that is kept off. Intermittent control is performed (S20 and subsequent steps). Even in the normal control, the PTC heater 50 is turned off by the procedures of S10, S12, and S18, and as long as it is on / off control, in this case, as described with reference to FIG. It is sufficiently longer than time T3 or cooling time T4. On the other hand, the on / off control in the procedure of S20 and subsequent steps is characterized in that the energization is turned on / off during the temperature rise time T3 and the time interval is short.

  Before explaining the details of the procedure from S20 onward, the contents of the intermittent energization control will be explained using the time chart shown in FIG. In FIG. 4, the horizontal axis represents time, and the vertical axis represents the voltage levels of the three signals 60, 62, and 64 and the temperature 66 of the PTC heater 50. The three signals are the energization prohibition / permission signal 60 that is the content of the signal line 48 from the DC / DC converter 16, the energization on / off signal 62 of the PTC heater 50 that is the signal of the relay 52, and the content of the 12V power supply line 46. Is a power supply voltage signal 64.

In FIG. 4, when t = t ₀ and the vehicle power supply is overloaded, the energization prohibition / permission signal 60 is at a prohibition level. And when t = _{t 1,} the procedure described in FIG. 2, the S10, S12 of the decision is positive both, the process proceeds to S14, where not determine that the no energization prohibited, the process proceeds to S20. That is, t = t ₁ is the starting point of intermittent energization control. Here, at t = t ₁ , the energization on / off signal 62 is turned on even though the energization prohibition / permission signal 60 indicates the prohibition state. As a result, the heater temperature 66 rises. Since also the power consumption of the PTC heater 50 is large, even as an overload condition of the vehicle power supply due to other loads in t = t ₁ after it has been eliminated, because the power consumption of the PTC heater 50, the power supply voltage signal 64 is reduced To do. In order to simplify the following description, it is assumed that the vehicle power supply overload state caused by a load other than the PTC heater 50 is eliminated, and the vehicle power supply overload occurs only when the PTC heater 50 is turned on.

The energization is not continued for a long time, but only during a time T1 that is sufficiently shorter than the temperature rise time T3 of the PTC heater 50 described in FIG. Accordingly, at time t = t ₁ + T1, the energization on / off signal 62 becomes an off signal, and the energization of the PTC heater 50 is stopped. Accordingly, the power consumption is eliminated, the power supply voltage signal 64 rises, and the overload of the vehicle power supply other than the PTC heater 50 has already been eliminated at this time. The signal 60 also changes to a permission signal.

The energization-off does not continue for a long time, but returns to the energization-on again only during a time T2 slightly shorter than the energization-on time T1. Therefore, at time t = t ₁ + T1 + T2, the energization on / off signal 62 becomes an on signal, and energization of the PTC heater 50 is resumed. Thus, since the energization off time T2 is shorter than the temperature rise time T3 of the PTC heater 50 and much shorter than the cooling time T4 of the PTC heater 50, the heater temperature 66 hardly decreases during the energization off time T2. Therefore, at the start of the next energization on (t = t ₁ + T1 + T2), the heater temperature 66 starts to increase from the heater temperature 66 almost the same as the end of the energization immediately before (t = t ₁ + T1).

Thus, even when the intermittent energization control of the PTC heater 50 is performed by taking the energization off time T2 sufficiently shorter than the natural cooling time T4 of the PTC heater 50 and taking an energization on / off ratio that can increase the temperature of the heater, The temperature of the PTC heater 50 can be raised. As an example, T3 = 20 seconds, T4 = 5 minutes, T1 = 3 seconds, T2 = 1 second, and energization on / off ratio = 3. At this time, if the temperature drop of the PTC heater 50 at T2 = 1 second can be ignored, the PTC heater 50 reaches a predetermined temperature of 150 ° C. when the accumulation of T1 reaches the same level as T3. Can do. Here, since the cumulative energization on time is 21 seconds at 7 times T1, if the PTC heater 50 reaches a predetermined temperature at this time, 6 seconds, which is the accumulation of the 6 energization off times so far, is added. The temperature of the PTC heater 50 can be sufficiently increased in 27 seconds from t = t ₁ when the energization is started.

  The length of the energization off time T2 is sufficiently shorter than the cooling time T4 of the PTC heater 50 as described above, and the power supply voltage signal 64 can be sufficiently recovered during the energization off time T2. is necessary. FIG. 4 shows that the power supply voltage signal 64 recovers when the energization on / off signal 62 is turned off. Since the power consumption of the PTC heater 50 is quite large, the power supply voltage signal 64 decreases at the start of energization, but conversely, the power supply voltage signal 64 recovers at the end of energization. Although T2 = 1 second is one example, when the power consumption of the PTC heater 50 is considerably larger than the power consumption of other devices, the power supply voltage signal 64 can be sufficiently recovered even in this time. When the power consumption of other devices is considerably large, recovery of the power supply voltage signal by delaying the power consumption of the PTC heater 50 may be delayed. Therefore, the energization on time T1 is preferably set in consideration of the degree of influence of the PTC heater 50 on the entire vehicle load.

  As described above, the energization on time T1 is sufficiently shorter than the temperature rise time T3 of the PTC heater 50, and at least one energization is performed until the PTC heater 50 rises to a predetermined temperature. It is necessary to recover the power supply voltage signal 64 so that the power supply voltage signal 64 can be turned off.

  Further, by imposing another condition on the energization on time T1, a better vehicle air conditioning method can be obtained. That is, as described in FIG. 1, the alarm output unit 42 of the ECB-ECU 40 monitors the voltage of the 12V power supply line 46, that is, the power supply voltage signal 64 in FIG. 4, and outputs an alarm signal as a result. More specifically, the voltage value indicated by the power supply voltage signal 64 is compared with a predetermined threshold, and an alarm signal is output when a period below the threshold continues beyond a predetermined determination period. Since the power supply voltage signal 64 continues to decrease during the energization on time T1, it may be below the threshold for this alarm signal. However, even if the power supply voltage signal 64 falls below the threshold value, if the duration is shorter than the judgment period TW for the alarm signal, no alarm signal is output. Therefore, by setting the energization on time T1 so as not to exceed the determination period TW, it is possible to avoid outputting an alarm signal due to energization of the PTC heater 50.

  As described above, when it is determined that there is no margin in the load of the power supply for the vehicle and energization of the PTC heater 50 is necessary, the temperature rise time T3 of the PTC heater 50, the cooling time T4 when the energization is not performed, ECB -Intermittent energization control in which the energization on time T1 and the energization off time T2 are appropriately set in consideration of the alarm signal determination period TW of the ECU 40 is performed.

Returning to FIG. 2 again, the contents of the procedure after S20 when it is determined that there is no margin in the load of the vehicle power source and the PTC heater 50 needs to be energized will be described. First, it is determined whether or not it is within T3 from the first energization on (S20). When it is not determined to be within T3, since not a step between t = t ₁ described in FIG. 4 of t = t 1 ₊ T3, then it is determined whether T4 has elapsed since the last de-energization (S22) .

  If it is determined that T4 has elapsed since the energization is turned off, as described with reference to FIG. 3, since the PTC heater 50 has been lowered to room temperature, the energization is turned on (S24). This ON is the first energization on after the PTC heater 50 has completely returned to room temperature, and may be referred to as the first energization on. The first energization on in S20 has the same meaning. In the determination of S22, instead of determining whether or not T4 has elapsed, it may be replaced with a determination of whether or not there is a usage history of the PTC heater 50 at all. If it is not determined in step S22 that T4 has elapsed, the process proceeds to step S18, the power supply is turned off, and the process returns to step S10 and starts again. After S24, the process returns to S10 again.

  When it is determined in S20 that it is within T3, the energization on / off control described in FIG. 4 is executed. First, it is determined whether or not the current is energized (S26). If energization is on, it is determined whether or not it is within T1 after energization is turned on (S28). If within energization, energization is continued until T1 is reached (S32). If the power is off, it is determined whether or not it is within T2 after the power is turned off (S30), and if it is within T2, the power is turned off until T2 is reached (S34). After S32 and S34, the process returns to S10 again. In this way, by repeating the energization on time T1 and the energization off time T2, the contents of the intermittent control described in FIG. 4 are executed.

1 is a block diagram of a vehicle air conditioner according to an embodiment of the present invention. It is a flowchart which shows the procedure of the air conditioning method of the vehicle in embodiment which concerns on this invention. It is a figure explaining the mode of a temperature rise when energizing and stopping an energization to a PTC heater in an embodiment concerning the present invention. It is a time chart of intermittent energization control in an embodiment concerning the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Vehicle power supply system, 12 HV high voltage battery, 14 SMR, 16 DC / DC converter, 18 12V battery, 20 Electric equipment, 22 Engine cooling water temperature detection means, 24 In-panel alarm display, 30 Vehicle air conditioner , 32 Air conditioning ECU, 34 Energization determination unit, 36 Load determination unit, 38 Energization control unit, 40 ECB-ECU, 42 Alarm output unit, 44 Warm-up switch, 46 Power line, 48 Signal line, 50 PTC heater, 52 Relay , 60 prohibition / permission signal, 62 energization on / off signal, 64 power supply voltage signal, 66 heater temperature.

Claims (4)

A heating element that is energized by a power source mounted on the vehicle and warms the passenger compartment of the vehicle;
A control unit that controls energization of the heating element based on the load state of the power source and performs air conditioning in the passenger compartment;
A vehicle air conditioner comprising:
The control unit
Energization determining means for determining whether it is necessary to energize the heating element to warm the passenger compartment;
A load determination means for determining whether the load state of the power supply is overload;
An energization control means for performing intermittent energization control using an energization on / off ratio capable of increasing the temperature of the heating element when it is necessary to energize the heating element and the power source is overloaded;
A vehicle air conditioner characterized by comprising: The vehicle air conditioner according to claim 1,
The control unit
An output means for outputting an alarm signal when the period during which the power supply voltage falls below a predetermined threshold exceeds an arbitrarily determined determination period;
The vehicle air conditioner is characterized in that the energization control means performs energization interruption using an energization on time shorter than a determination period for an alarm signal. The vehicle air conditioner according to claim 2,
The vehicle air conditioner characterized in that the energization control means performs energization interruption using an energization off time sufficient for the power supply voltage to recover beyond a predetermined threshold. A vehicle including a heating element that is energized by a power source mounted on the vehicle and warms the vehicle interior of the vehicle, and a control unit that controls energization of the heating element based on a load state of the power source and performs air conditioning in the vehicle interior An air conditioning method executed on an air conditioning apparatus,
An energization determining step for determining whether it is necessary to energize the heating element in order to warm the passenger compartment;
A load determination step for determining whether or not the load state of the power source is overload;
An energization control step for performing intermittent energization control using an energization on / off ratio that can increase the temperature of the heating element when it is necessary to energize the heating element and the power source is overloaded;
An air conditioning method for a vehicle, comprising:

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