Air conditioning device for electric vehicle
Patent Information
- Application Number
- PCT/JP2025/012542
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-03-27
- Publication Date
- 2026-10-01
Smart Images
Figure JP2025012542_01102026_PF_FP_ABST
Abstract
Description
Air conditioning apparatus for electric vehicle
[0001] The present invention relates to an air conditioning apparatus for an electric vehicle.
[0002] An electric vehicle generally includes a cooler for cooling a battery. Some battery coolers flow cabin air around the battery. In such a cooler, when the amount of exhaust heat from the battery increases, the air warmed by the exhaust heat returns to the cabin, which may cause discomfort to occupants.
[0003] Patent Document 1 describes that, in the battery cooler as described above, the battery cooler and a cabin air conditioner are operated in cooperation with each other.
[0004] Japanese Unexamined Patent Publication No. 2010-036723
[0005] A vehicle controller is responsible for controlling the traveling of an electric vehicle. Therefore, management is normally enhanced for sensors that input detection values to the vehicle controller so that normal traveling control is ensured. For example, the sensors are targets for failure diagnosis, and a record of an abnormality is stored when an abnormality occurs. Furthermore, the sensors may be required to have redundancy so that no abnormality occurs immediately even if they fail. In particular, in an electric vehicle including an internal combustion engine, the above-described redundancy is strongly required due to demands from exhaust gas regulations.
[0006] Among the plurality of sensors from which the vehicle controller receives detection values, there are cases where sensors having low relevance to traveling control are included. However, performing failure diagnosis and abnormality recording uniformly for all sensors from which the vehicle controller receives detection values can reduce management complexity.
[0007] From the above, when a detection value of a battery temperature sensor is sent to the vehicle controller in order to cause the battery cooler and the cabin air conditioner to cooperate with each other as in Patent Document 1, there arises a problem that enhanced management is also required for the temperature sensor. An increase in the number of sensors subject to enhanced management leads to corresponding increases in development costs and component costs.
[0008] The present invention aims to provide an air conditioning system for electric vehicles that can reduce discomfort to passengers from the battery cooler and further suppress the increase in the number of sensors that require enhanced management.
[0009] One aspect of the present invention relates to an air conditioning system for an electric vehicle, which is mounted on an electric vehicle comprising an engine that is an internal combustion engine for generating power for driving, an electric motor for generating power for driving, and a battery for storing the power supplied to the electric motor, the air conditioning system comprising: a temperature sensor for detecting the temperature of the battery; a battery cooler having a fan with a changeable airflow rate, which cools the battery by sending air from the passenger compartment with the fan; a battery management unit that receives temperature information detected by the temperature sensor and controls the airflow rate of the fan; an air conditioner for adjusting the temperature of the passenger compartment; and a vehicle controller for controlling the engine and the air conditioner, wherein the vehicle controller estimates the temperature of the battery and the airflow rate of the fan without using the temperature information detected by the temperature sensor and the control information of the fan, and controls the air conditioner using the result of the estimation.
[0010] According to the present invention, the vehicle controller controls the air conditioner using the estimated battery temperature and fan airflow rate, enabling air conditioner control that reduces discomfort to occupants from the battery cooler. Furthermore, since the vehicle controller uses the estimated battery temperature instead of the temperature sensor's detection value, the temperature sensor can be excluded from the sensors subject to enhanced management. This reduces the increase in the number of sensors subject to enhanced management, thereby lowering development costs and component costs.
[0011] This is a block diagram showing an electric vehicle equipped with an air conditioning system according to an embodiment of the present invention. This is a diagram showing the structure of the air conditioning system. This is a block diagram showing the functional configuration and peripheral configuration of the vehicle controller related to air conditioning control. This is the first part of a flowchart showing the procedure of the air conditioning control process performed by the vehicle controller. This is the second part of a flowchart showing the procedure of the air conditioning control process performed by the vehicle controller. This is a diagram explaining map M0. This is a diagram showing a specific example of map M1. This is a diagram showing a specific example of map M2. This is a diagram showing a specific example of map M3. This is a diagram explaining the procedure for calculating the strength of the air conditioner by the vehicle controller.
[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Figure 1 is a block diagram showing an electric vehicle 1 equipped with an air conditioning system 100 according to an embodiment of the present invention. Figure 2 is a diagram showing the structure of the air conditioning system 100. Figure 3 is a block diagram showing the functional configuration and peripheral configuration of a vehicle controller 10 related to air conditioning control.
[0013] The electric vehicle 1 equipped with the air conditioning system 100 of this embodiment is a Hybrid Electric Vehicle (HEV) that uses an internal combustion engine 3 and an electric motor 5 as power sources for driving. The electric vehicle 1 includes drive wheels 2, the above-mentioned power sources, a drive unit 4 that drives the engine 3, a battery 6 that stores the power supplied to the electric motor 5, an inverter 7 that converts power between the battery 6 and the electric motor 5, and an operation unit 8 on which the driver operates the vehicle. The operation unit 8 includes a steering unit 8a such as a steering wheel, a braking unit 8b such as a brake pedal, and an acceleration unit 8c such as an acceleration pedal. The operation unit 8 may also be operated by an automatic driving system.
[0014] The electric vehicle 1 further comprises a passenger cabin 11 for accommodating passengers, an air conditioner 20 for providing air conditioning to the passenger cabin, and a battery cooler 30 for cooling the battery 6. Passengers include the driver. The passenger cabin 11 includes front seats (driver's seat and passenger seat) 11a and rear seats 11b.
[0015] As shown in Figures 1 and 2, the air conditioner 20 includes a heat pump unit 21 that exchanges heat between air and a refrigerant, a blower unit 22 that sends temperature-controlled air to the passenger compartment via the heat pump unit 21, a front outlet 23 that blows temperature-controlled air to the front seats 11a of the passenger compartment 11, a rear outlet 24 that blows temperature-controlled air to the rear seats 11b of the passenger compartment 11, and air intake ports 25 and 26 for intake. The air conditioner 20 further includes an operation panel 28 that allows passengers to set the air conditioning settings, such as the room temperature of the passenger compartment 11. Passengers can operate the heat pump on and off, adjust the airflow, and set the temperature via the operation panel 28. A higher-level control device may also perform these settings.
[0016] The battery cooler 30 includes an air intake 31 for introducing cooling air from the passenger compartment 11, a fan 32 for circulating the air, and an outlet 33 for returning the air that has received heat from the battery 6 back to the passenger compartment 11. The battery cooler 30 also has an exhaust port for discharging the air that has received heat from the battery 6 to the outside of the vehicle, while the configuration may also be such that when outside air is not being introduced into the passenger compartment 11, the air that has received heat from the battery 6 is returned to the passenger compartment 11 via the outlet 33. The outlet 33 mainly directs the air to the rear seats 11b of the passenger compartment 11.
[0017] The electric vehicle 1 further includes a battery management unit 9 that manages the state of the battery 6 and controls the battery cooler 30, and a vehicle controller 10 that controls the operation of the engine 3, electric motor 5, and air conditioner 20. Furthermore, the electric vehicle 1 includes an outside temperature sensor 12 that detects the outside temperature, a solar radiation sensor 13 that detects the amount of solar radiation, a vehicle speed sensor 14 that detects the vehicle speed, and a passenger detection sensor 15 that detects the number of passengers in the passenger compartment 11. Furthermore, the electric vehicle 1 includes a temperature sensor 91, a voltage sensor 92, and a current sensor 93 that detect the temperature, voltage, and current of the battery 6, respectively.
[0018] Of the above configurations, the configuration including the vehicle controller 10, air conditioner 20, battery management unit 9, and battery cooler 30 corresponds to the air conditioning system 100 of this embodiment.
[0019] The battery management unit 9 is an ECU (Electronic Control Unit) and operates by executing programs stored in the memory unit 9a. As shown in Figure 3, the battery management unit 9 receives detection values from the temperature sensor 91, voltage sensor 92, and current sensor 93, and calculates various states of the battery 6, such as the State of Charge (SOC), output power, and input power, based on these detection values. The battery management unit 9 then manages the input and output of the battery 6 according to the calculated states. Furthermore, the battery management unit 9 controls the airflow of the fan 32 of the battery cooler 30. For example, the fan 32 is driven by a PWM (Pulse Width Modulation) signal, and the battery management unit 9 controls the airflow delivered by the fan 32 by changing the duty cycle of the PWM signal.
[0020] The vehicle controller 10 is an ECU (Electronic Control Unit) and controls the driving of the electric vehicle 1 and the air conditioning of the passenger compartment 11 by executing programs stored in the memory unit 10a. As shown in Figure 3, the outside temperature sensor 12, solar radiation sensor 13, vehicle speed sensor 14, and passenger detection sensor 15 send their respective detected values to the vehicle controller 10. The detected value of the battery 6 temperature sensor 91 and the airflow setting value of the fan 32 (for example, the duty cycle of the PWM signal) are not sent to the vehicle controller 10.
[0021] In driving control, the vehicle controller 10 receives driving operation signals from the driving operation unit 8 and signals indicating the vehicle status, such as the detected value from the vehicle speed sensor 14. In response to these signals, it operates the drive unit 4 and the inverter 7 to drive the engine 3 and the electric motor 5.
[0022] The vehicle controller 10 further controls the temperature of the passenger compartment 11 by adjusting the intensity of the air conditioner 20 according to the outside temperature, solar radiation, the number of passengers in the passenger compartment 11, and the settings on the control panel 28. The intensity of the air conditioner 20 can be changed, for example, by increasing or decreasing the amount of air blown by the blower unit 22, increasing or decreasing the amount of heat exchanged by the heat pump unit 21, or both.
[0023] The vehicle controller 10 has a fault diagnosis function 10b that targets multiple sensors that send detected values to the vehicle controller 10. The fault diagnosis function 10b is, for example, OBD (On-Board Diagnostics) and includes a function to record abnormal information in the event of a sensor failure. This abnormal information includes, for example, a DTC (Diagnostic Trouble Code). Furthermore, the multiple sensors that send detected values to the vehicle controller 10 are redundant so that even if one failure occurs, it does not abnormally affect the control by the vehicle controller 10. Hereinafter, anything that is subject to at least one of the above-mentioned fault diagnosis function 10b and redundancy assurance will be referred to as "subject to enhanced management". The multiple sensors subject to enhanced management include an outside temperature sensor 12, a solar radiation sensor 13, a vehicle speed sensor 14, and a passenger detection sensor 15. On the other hand, the battery temperature sensor 91 and the detection configuration for the airflow setting value of the fan 32 do not send detected values to the vehicle controller 10 and are therefore not included in the subject of enhanced management.
[0024] In this embodiment, the electric vehicle 1 has regular operating conditions for the electric motor 5, such that the electric motor 5 is driven during acceleration and low-speed driving, and regenerative driving is performed when the electric vehicle 1 is decelerating. The engine 3 is assisted by the power driving during acceleration, and energy efficiency can be improved by storing regenerative power in the battery 6 during regenerative driving during deceleration. Due to these regularities, the trend of the charge and discharge amount of the battery 6 is determined according to the driving pattern of the electric vehicle 1. Therefore, the vehicle controller 10 can predict the charge and discharge amount of the battery 6, as well as the trend of temperature changes of the battery 6, based on driving parameters such as the vehicle speed and acceleration of the electric vehicle 1.
[0025] <Air Conditioning Control of Passenger Compartment 11> The following describes the case where the passenger compartment 11 is cooled using the air conditioner 20. First, an overview will be given. Figure 3 is a diagram illustrating the functional configuration and peripheral configuration related to the air conditioning control of the vehicle controller 10. The vehicle controller 10 controls the intensity of the air conditioner 20 (for example, the air temperature at outlets 23 and 24, the airflow at outlets 23 and 24, etc.) so that the settings made by the passengers (for example, the room temperature) are realized. Even if the settings are the same, if the outside temperature, amount of sunlight, number of passengers, etc. are different, it is necessary to change the intensity of the air conditioner 20 in order to realize the settings. In addition, when the exhaust heat from the battery 6 is returned to the passenger compartment 11 by the battery cooler 30, it is preferable that the intensity of the air conditioner 20 can be changed according to the amount of exhaust heat in order to realize the settings made by the passengers or to avoid causing discomfort to the passengers.
[0026] The vehicle controller 10 can identify the outside temperature, solar radiation, and number of passengers based on the values detected by the outside temperature sensor 12, the solar radiation sensor 13, and the passenger detection sensor 15. On the other hand, the vehicle controller 10 cannot directly detect the amount of waste heat returned from the battery cooler 30 to the passenger compartment 11. This is because the values detected by the temperature sensor 91 of the battery 6 and the airflow setting values of the fan 32 are not sent to the vehicle controller 10.
[0027] The vehicle controller 10 estimates the temperature of the battery 6 and the airflow rate of the fan 32 using other information, without using the temperature sensor 91's detection value and the fan 32's airflow rate setting value. As shown in Figure 3, the vehicle controller 10 has maps M0 to M3, which it uses to perform the above estimation. Details of maps M0 to M3 will be described later. Then, the vehicle controller 10 calculates the amount of exhaust heat to be returned to the passenger compartment 11 from the results of the above estimation and controls the air conditioner 20 to offset this amount of exhaust heat.
[0028] According to the control of the air conditioner 20 described above, even if the heat dissipated by the battery 6 increases, the cooling intensity of the air conditioner 20 can be increased accordingly, thereby reducing the discomfort caused to passengers by the heat dissipated by the battery 6. Furthermore, since the detected value of the temperature sensor 91 and the airflow setting value of the fan 32 are not sent to the vehicle controller 10, the sensors related to the temperature sensor 91 and the airflow setting of the fan 32 can be excluded from the scope of enhanced management. Therefore, component costs and development costs can be reduced.
[0029] <Air Conditioning Control Processing> Next, the details of air conditioning control will be explained. Figures 4 and 5 are flowcharts showing the procedure for air conditioning control processing performed by the vehicle controller 10. Air conditioning control processing is started when the vehicle controller 10 is started. For example, when a passenger turns on the power button of the electric vehicle 1 or turns on the ignition key, the vehicle controller 10 starts up and the air conditioning control processing begins. The vehicle controller 10 then first performs initial processing associated with startup (step S1), and then uses map M0 to perform estimation processing of the initial temperature Tb0 of the battery 6 (i.e., the temperature at startup) (step S2).
[0030] <<Estimation Process 1 - Estimation of Initial Battery Temperature>> Figure 6 is a diagram illustrating map M0. Map M0 is a map that relates three values—the ambient temperature at the time of the previous startup, the ambient temperature at the time of the current startup, and the elapsed time from the time of the previous startup to the time of the current startup—to the initial temperature Tb0 of the battery 6. During the idle period of the electric vehicle 1, the temperature of the battery 6 approaches the ambient temperature along a predetermined temperature transition curve. Although the ambient temperature changes, the transition of the ambient temperature between the time of the previous startup and the time of the current startup is roughly determined by the ambient temperature at the time of the previous startup and the ambient temperature at the time of the current startup. Therefore, unless the idle period is extremely short, regardless of the temperature of the battery 6 when the electric vehicle 1 is running, the temperature of the battery 6 will be a temperature corresponding to the ambient temperature at the time of the previous startup, the ambient temperature at the time of the current startup, and the elapsed time mentioned above. Map M0 derives this temperature as the initial temperature Tb0 of the battery 6. Map M0 can be created based on the results of experiments in which the temperature of the battery 6 is measured under different conditions in which the three values mentioned above are varied, or on the results of equivalent simulations.
[0031] In the estimation process of step S2 described above, the vehicle controller 10 calculates the three values from the time and the output of the ambient temperature sensor 12 at the time of the current startup, and the time and the output of the ambient temperature sensor 12 at the time of the previous startup, which were stored at the time of the previous startup. Then, the vehicle controller 10 refers to map M0 and reads out the initial temperature Tb0 of the battery 6 corresponding to these three values as an estimated value.
[0032] <<Continued from air conditioning control process>> Next, the vehicle controller 10 determines whether the temperature Tb0 of the battery 6, Tb is above a threshold temperature (step S3) and whether the air conditioner 20 has been turned on by the passenger (step S4). The threshold temperature in step S3 is set to a value related to the minimum temperature of the battery 6 at which the battery cooler 30 operates and the air conditioner 20 needs to operate in order to offset the heat dissipated from the battery 6 (for example, the above minimum value - temperature margin). The battery cooler 30 is controlled by the battery management unit 9.
[0033] If the result of both steps S3 and S4 is NO, the process proceeds to step S6. On the other hand, if the result of either step S3 or S4 is YES, the cooling operation of the air conditioner 20 is started (step S5), and then the process proceeds to step S6.
[0034] Next, the vehicle controller 10 obtains the vehicle speed from the detected value of the vehicle speed sensor 14 (step S6), and obtains the acceleration of the electric vehicle 1 by calculating the time change of the detected value of the vehicle speed sensor 14 (step S7). Note that the electric vehicle 1 has an acceleration sensor, and in step S7, the vehicle controller 10 may obtain the acceleration from the detected value of the acceleration sensor.
[0035] Furthermore, the vehicle controller 10 obtains the output power of the engine 3 from the parameters of the engine 3's drive process (step S8). The vehicle controller 10 performs drive control of the engine 3 and the electric motor 5 in parallel with the air conditioning control process. Therefore, the vehicle controller 10 can calculate the output power from the rotational speed of the engine 3 obtained during the drive control, as well as the torque data of the engine 3 that it holds.
[0036] Next, the vehicle controller 10 uses map M1 to estimate the amount of temperature rise ΔTb of the battery 6, and then estimates the temperature of the battery 6 by integrating the estimated amount of temperature rise ΔTb with the initial temperature Tb0 (step S9).
[0037] <<Estimation Process 2 - Estimation of Battery 6 Temperature Increase ΔTb>> Figure 7 shows a specific example of map M1. Map M1 is a map that relates two values, the average vehicle speed and the magnitude of the average acceleration, over a predetermined first time period (e.g., 30 seconds), to the temperature increase ΔTb of the battery 6 over the first time period. The average vehicle speed is the average vehicle speed, but it can be replaced with various other values that indicate the average vehicle speed, such as the average value of the vehicle speed excluding outliers, or an index number indicating which group the average vehicle speed belongs to when it is divided into multiple groups. The magnitude of the average acceleration is, for example, the root mean square of the acceleration, but it can be replaced with various other values that indicate the magnitude of the average acceleration (regardless of the longitudinal direction), such as the average value of the absolute value of the acceleration, or an index number indicating which group the average acceleration belongs to when it is divided into multiple groups.
[0038] As mentioned above, if there is a predetermined regularity in the operating conditions of the electric motor 5, the approximate degree of operation of the electric motor 5 and battery 6 can be determined by a small number of parameters representing the driving state, and the approximate temperature rise ΔTb of the battery 6 can be determined accordingly. In the electric vehicle 1 of this embodiment, the approximate temperature rise ΔTb of the battery 6 is determined from the average vehicle speed and the magnitude of the average acceleration, based on the regularity of the operating conditions of the electric motor 5 as described above. Map M1 derives the temperature rise ΔTb from the above two values.
[0039] Map M1 can be created based on the results of experiments or equivalent simulations that measure the temperature rise ΔTb of the battery 6 under different conditions for the two values mentioned above. In Map M1, the average vehicle speed may be rounded to 20 [km / h] intervals, as described later. Similarly, the magnitude of the average acceleration is 1.0 [m / sec] 2A value subjected to the rounding processing described later, such as for each
[0040] The estimation processing in step S9 is repeatedly executed during operation of the air conditioner in the loop processing of steps S3 to S10 or the loop processing of steps S6 to S15. The vehicle speed and acceleration acquisition processing in steps S6 and S7 is executed in each loop of the above loop processing. On the other hand, the estimation processing in step S9 is executed in a specific loop in the above loop processing, for example, a loop of a predetermined calculation cycle (e.g., 30 seconds), and is not substantially executed in other loops.
[0041] When the estimation processing of step S9 is started in a loop of the predetermined calculation cycle, first, the vehicle controller 10 calculates an average vehicle speed and an average acceleration magnitude from the large number of vehicle speeds and the large number of accelerations acquired in steps S6 and S7 of each loop. Then, the vehicle controller 10 refers to the map M1, and reads out a battery temperature increase amount ΔTb corresponding to the calculated average vehicle speed and average acceleration magnitude as an estimated value.
[0042] <<Continuation of Control Processing>> Subsequently, in step S9 repeatedly executed in loop processing, the vehicle controller 10 estimates the current temperature Tb of the battery 6 by accumulating the estimated temperature increase amount ΔTb to the initial temperature Tb0 of the battery 6.
[0043] Next, the vehicle controller 10 determines whether the air conditioner 20 is in operation (step S10), and if NO, the processing returns to step S3. On the other hand, if YES, the vehicle controller 10 executes estimation processing of the air volume Qf of the fan 32 of the battery cooler 30 (step S11) and estimation processing of the intensity addition amount ΔQr of the air conditioner 20 (step S12).
[0044] <<Estimation Process 3 - Estimation of Fan 32 Airflow Qf>> Figure 8 shows a specific example of map M2. Map M2 is a map that associates two values, a quantity related to vehicle speed and a quantity related to the output power of engine 3, with the airflow of fan 32 of the battery cooler 30. The quantity related to vehicle speed may be the vehicle speed at each point in time, or the average vehicle speed over a predetermined second time length. The quantity related to the output power of engine 3 may be the output power at each point in time, or the average output power over the above second time length. The above second time length may be the time length corresponding to the time interval of the control cycle for switching the intensity of fan 32.
[0045] In the electric vehicle 1 of this embodiment, based on the regularity of the operating conditions of the electric motor 5 described above, a regularity also arises in the power sharing between the engine 3 and the electric motor 5 according to the driving conditions. Furthermore, there is a relationship between the degree of operation of the electric motor 5 and the battery 6 and the cooling intensity of the battery 6. In such cases, the approximate degree of operation of the electric motor 5 and the battery 6 is determined by parameters related to the power of the engine 3 and parameters representing the vehicle state, and the cooling intensity of the battery 6, i.e., the approximate airflow Qf of the fan 32, may be determined. In the electric vehicle 1 of this embodiment, the approximate airflow Qf of the fan 32 is determined from the quantity related to the output power of the engine 3 and the quantity related to the vehicle speed. Map M2 derives the fan airflow Qf from these two quantities.
[0046] The map M2 can be created based on the results of an experiment that measures the air volume Qf of the fan 32 under each condition where the two values are made different, or an equivalent simulation. In the map M2, rounded values such as "5, 20, 40, 60... [km / h]" may be adopted for the vehicle speed. Rounding is a process of removing the remainder from the target value when the target value is divided by a base. The base is not limited to 10, and may be a value larger than 10 (e.g., 20), and the base does not have to be constant and may correspond to when the vehicle speed is low or high respectively. In the above case, the base is set to 5 when the vehicle speed is less than 10 [km / h]. Similarly, for the output power of the engine 3, a rounded value based on a predetermined value such as every 20 [kW] may be adopted.
[0047] The estimation process in step S11 is repeatedly executed in the loop processing of steps S6 to S15 when the air conditioner 20 is in operation. The acquisition process of the vehicle speed and the output power of the engine 3 in steps S6 and S9 is executed, for example, in every loop. On the other hand, the estimation process in step S11 only needs to be executed at a cycle corresponding to the control cycle in which the intensity of the fan 32 is switched.
[0048] When the estimation process of step S11 is started at the corresponding cycle, first, the vehicle controller 10 extracts the vehicle speed and output power acquired in the immediately preceding steps S6 and S8. Note that the vehicle speed and output power may be replaced with an average vehicle speed and an average output power calculated from a large number of vehicle speeds and a large number of output powers acquired in a plurality of immediately preceding loop processes. Then, the vehicle controller 10 refers to the map M2 and reads the air volume Qf of the fan 32 corresponding to the vehicle speed and the output power as an estimated value.
[0049] <<Estimation Process 4 - Estimation of the Intensity Addition Amount ΔQr of the Air Conditioner 20>> Figure 9 shows a specific example of map M3. Map M3 is a map that associates two values, the temperature Tb of the battery 6 and the airflow Qf of the fan 32, with the intensity addition amount ΔQr of the air conditioner 20. When the temperature Tb of the battery 6 rises and the airflow Qf of the fan 32 increases, the amount of exhaust heat returned from the battery cooler 30 to the passenger cabin increases, causing discomfort to the passengers. On the other hand, even if the amount of exhaust heat increases, the discomfort to passengers due to the exhaust heat can be reduced by adding the cooling intensity of the air conditioner 20. The intensity addition amount ΔQr of the air conditioner 20 that reduces passenger discomfort changes according to the temperature Tb of the battery 6 and the airflow Qf of the fan 32. Map M3 shows the appropriate correspondence between these.
[0050] Map M3 can be created based on the results of experiments or equivalent simulations that measure the appropriate intensity addition amount ΔQr for the air conditioner 20 under different conditions for the two values mentioned above. In Map M3, the temperature Tb of the battery 6 may be a rounded value such as "30, 35, 40, 50... [°C]". Similarly, the airflow Qf of the fan 32 is 20 [m³]. 3 The above rounded values such as [ / h] may also be used.
[0051] The estimation process in step S12 is repeatedly executed within the loop processing of steps S6 to S15 when the air conditioner 20 is in operation. This estimation process may be executed in each loop of the loop processing, or it may be executed at a frequency corresponding to the control cycle in which the intensity of the air conditioner 20 is switched, or the control cycle in which the intensity of the fan 32 is switched.
[0052] When the estimation process in step S12 begins, the vehicle controller 10 first extracts the battery temperature 6 estimated in step S9 and the fan airflow Qf estimated in step S11. Then, the vehicle controller 10 refers to map M3 and reads out the estimated intensity sum ΔQr of the air conditioner 20 corresponding to the estimated battery temperature Tb and fan airflow Qf.
[0053] <<Continued from air conditioning control process>> Next, the vehicle controller 10 calculates the uncorrected intensity Qr0 requested from the air conditioner 20 based on the external environment (e.g., outside air temperature and solar radiation), the indoor environment (number of passengers and indoor temperature), and the intensity setting value of the air conditioner 20 (e.g., set temperature and airflow rate) (step S13). Note that the uncorrected intensity Qr0 may be calculated based on two or more pieces of information from the external environment, indoor environment, and the intensity setting value of the air conditioner 20.
[0054] Next, the vehicle controller 10 adds the intensity sum ΔQr estimated in step S12 to the pre-correction intensity Qr0 calculated in step S12, and calculates the actual intensity Qr of the air conditioner 20 to be operated (= Qr0 + ΔQr), and drives the air conditioner 20 at that intensity (step S14).
[0055] Furthermore, if a large amount of heat from the battery 6 is returned to a specific location in the passenger compartment 11, such as the rear seat 11b, the strength addition amount ΔQr of the air conditioner 20 may be the strength addition amount ΔQr of the air conditioner 20 for that specific location. For example, the strength addition amount ΔQr may be the strength addition amount of the blower fan that sends cool air to the rear seat 11b, and the strength addition amount ΔQr may result in a configuration where the amount of air sent to the rear seat 11b in Example 9 increases. Also, if the blower unit 22 has a multi-stage blower fan, and the strength addition amount ΔQr represents the strength addition amount of each of the multi-stage blower fans, the strength addition amount ΔQr may be the value obtained by dividing the total strength addition amount by the number of stages of the blower fan.
[0056] Next, the vehicle controller 10 determines whether the air conditioning control termination condition is met (step S15). If the condition is NO, the process returns to step S6; however, if the condition is YES, the air conditioning control process is terminated.
[0057] <Summary of the calculation procedure for the strength of the air conditioner> Figure 10 is a diagram illustrating the calculation procedure for the strength of the air conditioner 20 by the vehicle controller 10. The calculation procedure for the strength Qr of the air conditioner 20 in the above air conditioning control process is summarized in Figure 10.
[0058] Specifically, the vehicle controller 10 estimates the temperature Tb of the battery 6 from the initial temperature Tb0 of the battery 6 estimated in step S2 using map M0 and the temperature rise ΔTb of the battery 6 estimated in step S9 using map M1 (step S9). Furthermore, the vehicle controller 10 estimates the airflow Qf of the fan 32 of the battery cooler 30 using map M2 (step S11). Then, the vehicle controller 10 estimates the intensity addition amount ΔQr of the air conditioner 20 using map M3 from the estimated values in steps S9 and S11 (step S12). Then, by adding the intensity addition amount ΔQr to the intensity Qr0 of the air conditioner 20 before correction calculated in step S13, the vehicle controller 10 calculates the intensity Qr of the air conditioner 20 to be actually driven and drives the air conditioner 20 (step S14).
[0059] The air conditioning control processing program described above is stored in a non-transient storage medium (non-transient computer-readable medium), such as the storage unit 10a of the vehicle controller 10. The vehicle controller 10 may be configured to read a program stored on a portable non-transient recording medium and execute the program. The portable non-transient storage medium described above may store the air conditioning control processing program described above.
[0060] As described above, with the air conditioning system 100 of this embodiment, the vehicle controller 10 controls the air conditioner 20 in the passenger compartment 11 using the estimated results of the battery temperature 6 and the airflow rate of the fan 32. Therefore, it becomes possible to control the air conditioner 20 in a way that reduces discomfort to passengers from the battery cooler 30. Furthermore, since the vehicle controller 10 uses the estimated temperature of the battery 6 without using the detection value of the battery temperature sensor 91, the temperature sensor 91 can be excluded from the sensors subject to enhanced management. By suppressing the increase in the number of sensors subject to enhanced management, development costs and component costs can be reduced.
[0061] Furthermore, according to the air conditioning system 100 of this embodiment, the vehicle controller 10 controls the intensity of the air conditioner 20 in accordance with the amount of heat exhausted from the battery 6 sent to the passenger compartment 11 by the battery cooler 30. Thus, control of the air conditioner 20 that reduces discomfort to passengers from the battery cooler 30 is achieved.
[0062] Furthermore, according to the air conditioning system 100 of this embodiment, the vehicle controller 10 estimates the initial temperature of the battery at the time of the current startup based on the elapsed time from the previous startup to the current startup and the ambient temperature. In addition, the vehicle controller 10 estimates the amount of temperature rise ΔTb of the battery 6 based on the average vehicle speed and the magnitude of the average acceleration, and estimates the temperature of the battery 6 by integrating the amount of temperature rise ΔTb. With this estimation method, the vehicle controller 10 can estimate the temperature of the battery 6 with reasonable accuracy without receiving the output of the temperature sensor 91 of the battery 6.
[0063] Furthermore, according to the air conditioning system 100 of this embodiment, the airflow Qf of the fan 32 of the battery cooler 30 is estimated based on a quantity related to the vehicle speed and a quantity related to the output power of the engine 3. With this estimation method, the vehicle controller 10 can estimate the airflow Qf of the fan 32 of the battery cooler 30 with reasonable accuracy without receiving control information such as the drive duty cycle of the fan 32.
[0064] Furthermore, according to the air conditioning system 100 of this embodiment, the vehicle controller 10 calculates the pre-correction intensity Qr0 of the air conditioner 20 based on information about the external environment, the intensity setting value of the air conditioner 20, and the number of passengers. In addition, the vehicle controller 10 calculates an additional amount ΔQr of the intensity of the air conditioner 20 based on the estimated temperature of the battery 6 and the estimated airflow Qf of the fan 32, and controls the air conditioner 20 to an intensity that is the pre-correction intensity Qr0 plus the additional amount ΔQr. Therefore, the vehicle controller 10 can control the air conditioner 20 to reduce discomfort transmitted from the battery cooler 30 to the passengers with minimal excess or deficiency, without receiving the detected temperature of the battery 6 or control information of the fan 32 of the battery cooler 30.
[0065] Embodiments of the present invention have been described above. However, the present invention is not limited to the embodiments described above, and the details shown in the embodiments can be modified as appropriate without departing from the spirit of the invention.
[0066] This invention can be used in air conditioning systems for electric vehicles.
[0067] 1 Electric vehicle 2 Drive wheels 3 Engine 4 Drive system 5 Electric motor 6 Battery 7 Inverter 8 Operating controls 9 Battery management unit 10 Vehicle controller 10b Fault diagnosis function 11 Passenger compartment 12 Outside temperature sensor 13 Solar radiation sensor 14 Vehicle speed sensor 15 Passenger detection sensor 20 Air conditioner 21 Heat pump unit 22 Blower unit 23, 24 Air outlet 25, 26 Air intake 28 Control panel 30 Battery cooler 31 Air intake 32 Fan 33 Outlet 91 Temperature sensor 92 Voltage sensor 93 Current sensor 100 Air conditioning system M0-M3 Map
Claims
1. An air conditioning system for an electric vehicle, which is mounted on an electric vehicle comprising an engine that is an internal combustion engine for generating power for driving, an electric motor for generating power for driving, and a battery for storing the power supplied to the electric motor, comprising: a temperature sensor for detecting the temperature of the battery; a battery cooler having a fan with a changeable airflow rate, which cools the battery by sending air from the passenger compartment with the fan; a battery management unit that receives temperature information detected by the temperature sensor and controls the airflow rate of the fan; an air conditioner for adjusting the temperature of the passenger compartment; and a vehicle controller for controlling the engine and the air conditioner, wherein the vehicle controller estimates the temperature of the battery and the airflow rate of the fan without using the temperature information detected by the temperature sensor and the control information of the fan, and controls the air conditioner using the result of the estimation.
2. The air conditioning system for an electric vehicle according to claim 1, characterized in that the vehicle controller controls the intensity of the air conditioner in accordance with the amount of heat exhausted from the battery sent to the passenger compartment by the battery cooler.
3. An air conditioning system for an electric vehicle according to claim 1, further comprising an ambient temperature sensor for detecting ambient temperature, wherein the vehicle controller inputs ambient temperature information detected by the ambient temperature sensor, estimates the initial temperature of the battery at the time of the current startup based on the elapsed time from the previous startup to the current startup and the ambient temperature, estimates the amount of temperature rise of the battery based on the average vehicle speed and the average acceleration magnitude, and estimates the temperature of the battery based on the estimated initial temperature and the amount of temperature rise.
4. The air conditioning system for an electric vehicle according to claim 1, characterized in that the vehicle controller estimates the amount of air blown by the fan based on a quantity relating to the vehicle speed and a quantity relating to the output power of the engine.
5. The air conditioning system for an electric vehicle according to claim 1, characterized in that the vehicle controller calculates the uncorrected intensity of the air conditioner based on at least two pieces of information: the external environment, the intensity setting value of the air conditioner, and the number of passengers; calculates an additional amount for the intensity of the air conditioner based on the estimated battery temperature and the estimated airflow rate of the fan; and controls the air conditioner to an intensity equal to the uncorrected intensity plus the additional amount.