Electric vehicle air conditioning control system and control method

Abstract

An electric vehicle air-conditioning control system and control method, the system includes a central controller, an electromagnetic clutch and an air-conditioning controller, the central controller is respectively connected with the electromagnetic clutch, the air-conditioning controller and a battery in the vehicle, a brake light switch, and a temperature sensor in the battery; the electromagnetic clutch is arranged between the air-conditioning compressor and the rotor of a driving motor driving the wheels to rotate and is suitable for directly mechanically connecting the two; the control method controls the engagement and disconnection of the electromagnetic clutch respectively according to the working mode of the air-conditioning, the battery temperature and the state of the brake switch, so as to realize the on-demand connection between the rotor of the air-conditioning compressor and the rotor of the driving motor, reduce the abnormal working temperature, the charging and discharging frequency of the battery and the charging and discharging current, and extend the service life of the battery.

Description

Technical Field

[0001] The invention relates to an electric vehicle air-conditioning control system and a control method. Background Art

[0002] For cars with internal combustion engines, the internal combustion engines need cooling water to cool and dissipate heat. When the car needs to be heated, the heat of the engine cooling water can be used to heat the interior of the car. Therefore, there is no need to start the air-conditioning compressor for heating in winter, thereby saving energy consumption. At the same time, for cars with internal combustion engines, since the air-conditioning compressor is directly driven by the crankshaft of the internal combustion engine through a belt, the operation of the air-conditioning compressor will increase the fuel consumption of the internal combustion engine, but the operation of the compressor will not consume the power in the battery on the car. In comparison, since electric vehicles do not have internal combustion engines, the air-conditioning compressor must be started regardless of whether the car needs to be cooled or heated. The air-conditioning compressor is driven by its own motor, and the working process of the air-conditioning compressor consumes the power in the battery. In the prior art, the working process of the air-conditioning compressor of an electric vehicle directly uses the power in the battery, and the power in the battery comes from external charging and vehicle braking energy recovery. This means that when the air conditioner is turned on, the kinetic energy recovered by braking energy is first converted into electricity through the motor and stored in the battery, and then the battery supplies the stored electricity to the air conditioner compressor; since the kinetic energy is converted into electrical energy by the driving motor, the motor temperature will rise, and the converted electrical energy will charge the battery and discharge the battery to the outside, which will also cause the battery to heat up, thereby losing some energy and causing a waste of electricity. Especially when the battery temperature is outside the normal operating temperature range, the battery charging and discharging efficiency is lower, and the energy loss generated during the charging and discharging process is greater. At this time, if a part of the kinetic energy recovered by braking energy can be directly converted into the rotor kinetic energy of the air conditioner compressor, the energy conversion process in the above process will be eliminated, reducing more energy waste. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] To solve the problem of energy waste caused by converting braking energy into electrical energy and storing it in a battery in the prior art, and then releasing the electrical energy in the battery to drive an air-conditioning compressor, the present invention provides an electric vehicle air-conditioning control system. An electromagnetic clutch is provided between the air-conditioning compressor and the driving motor. The electromagnetic clutch is respectively connected to the rotor of the air-conditioning compressor and the rotor of the driving motor. The central controller controls the engagement and disconnection of the electromagnetic clutch as needed, so that when needed, the rotor of the air-conditioning compressor is directly connected to the rotor of the driving motor. When the vehicle brakes, the kinetic energy of the vehicle is directly transmitted to the air-conditioning compressor, thereby improving the utilization efficiency of the recovered braking energy and reducing the above-mentioned energy waste. The present invention also provides an electric vehicle air-conditioning control method, which respectively controls the engagement and disconnection of the electromagnetic clutch according to the working mode of the air conditioner, the battery temperature, and the state of the braking switch, realizes the on-demand connection of the rotor of the air-conditioning compressor and the rotor of the driving motor, reduces the charge and discharge frequency and current of the battery under abnormal working temperatures, and prolongs the service life of the battery.

[0005] (2) Technical solutions

[0006] To solve the above technical problems, the present invention provides the following technical solutions:

[0007] An electric vehicle air-conditioning control system mainly includes a central controller, an electromagnetic clutch, and an air-conditioning controller. The central controller is respectively connected to the electromagnetic clutch, the air-conditioning controller, the battery in the vehicle, the braking light switch, and the temperature sensor in the battery; the electromagnetic clutch is arranged between the air-conditioning compressor and the rotor of the driving motor that drives the wheels to rotate and is adapted to directly mechanically connect the two.

[0008] The electric vehicle air-conditioning control system further includes a braking pressure sensor, and the braking pressure sensor is connected to the central controller.

[0009] An electric vehicle air-conditioning control method includes the following steps:

[0010] (1) Use the central controller set in the vehicle to collect the signal of the temperature sensor in the battery;

[0011] (2) When the air conditioner is started, judge the working mode of the air conditioner,

[0012] 1) When the air conditioner is in the heating mode, if the relationship between the temperature T of the battery and the lower limit value T1 of the normal working temperature range of the battery is T < T1 and the braking light switch is not turned on, or the temperature T of the battery ≥ T1, the electromagnetic clutch for connecting the rotor of the air-conditioning compressor and the rotor of the driving motor of the vehicle wheels is disengaged; if the temperature T of the battery < T1 and the braking light switch is turned on, the electromagnetic clutch is energized and engaged;

[0013] 2) In the refrigeration mode of the air conditioner, if the relationship between the temperature T of the battery and the upper limit value T2 of the normal operating temperature range of the battery is T > T2 and the brake light switch is not turned on, or the temperature T of the battery ≤ T2, then the electromagnetic clutch disengages and disconnects; if the temperature T of the battery > T2 and the brake light switch is turned on, then the electromagnetic clutch is energized and engaged;

[0014] (3) Return to step (1).

[0015] When the electromagnetic clutch is about to be energized and engaged under the condition, judge the relationship between the braking pressure P measured by the braking pressure sensor set in the vehicle and the set values P1 and P2;

[0016] ① When the braking pressure P < P1, the engagement rate Q of the electromagnetic clutch = 0.3;

[0017] ② When the braking pressure P1 ≤ P < P2, the engagement rate Q of the electromagnetic clutch = 0.7;

[0018] ③ When the braking pressure P ≥ P2, the engagement rate Q of the electromagnetic clutch = 1.

[0019] Furthermore, P1 is 30% of the maximum braking pressure of the master cylinder, and P2 is 60% of the maximum braking pressure of the master cylinder.

[0020] (III) Beneficial effects

[0021] The present invention provides an electric vehicle air conditioner control system and a control method. It has the following beneficial effects:

[0022] 1. The electric vehicle air conditioner control system of the present invention enables the moving vehicle to directly convert the braking energy into the driving energy of the air conditioner compressor, avoiding the process of first converting the braking energy into electrical energy and then using the electrical energy to drive the air conditioner compressor, thus making the energy utilization efficiency higher.

[0023] 2. By using the braking pressure detected by the braking pressure sensor, it is possible to adjust the rotational resistance torque transmitted from the air conditioner compressor as a load to the driving motor according to the depth of the brake pedal depressed by the driver, so that the rotational resistance torque increases synchronously with the braking force required by the driver, thereby improving the riding comfort of the passengers in the vehicle.

[0024] 3. When the temperature of the battery exceeds the normal operating temperature range, its charge and discharge efficiency is lower than the normal state; by setting different control methods for the air conditioner in the heating and refrigeration modes, the braking energy conversion efficiency under the braking condition of the vehicle is improved; by directly transmitting power through the power connection between the driving motor and the air conditioner compressor without transferring energy through the battery, the charge and discharge frequency and current of the battery under abnormal working temperatures are reduced, and the service life of the battery is extended.

[0025] 4. When the electromagnetic clutch is engaged, it is divided into three ranges according to the depth of the brake pedal pressed by the driver or the required braking force, and the engagement rate of the electromagnetic clutch is used to adjust the rotational resistance torque transmitted from the air-conditioning compressor to the driving motor. This not only improves the riding comfort of the passengers in the car, but also improves the convenience of control and reduces the complexity of control, which is beneficial to reduce the operating temperature of the electromagnetic clutch and increase its service life.

[0026] 5. Using 30% and 60% of the maximum brake pressure of the master brake cylinder as segmentation nodes for dividing the range can better fit the actual working conditions of the driver during driving and balance the passenger's riding comfort and the rotational resistance torque transmitted to the driving motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0028] Figure 1 This is a structural diagram of the electric vehicle air conditioning control system according to the first embodiment;

[0029] Figure 2 This is a flow chart of a first embodiment of an electric vehicle air conditioning control method;

[0030] Figure 3 This is a flow chart of Embodiment 2 of the electric vehicle air conditioning control method;

[0031] Figure 4 This is a schematic diagram of the power-on time when the bonding rate is 0.3;

[0032] Figure 5 It is a schematic diagram of the power-on time when the bonding rate is 0.7;

[0033] Figure 6 It is a schematic diagram of the power-on time when the bonding rate is 1;

[0034] Figure 7 This is a structural diagram of the electric vehicle air conditioning control system according to the second embodiment. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0036] Embodiment 1

[0037] In this embodiment 1, Figure 1As shown in the figure, the electric vehicle air-conditioning control system includes a central controller and an electromagnetic clutch. The electromagnetic clutch is respectively connected to the rotor of the air-conditioning compressor and the rotor of the driving motor of the driving wheels. The electromagnetic clutch is in the engaged state when powered on and in the disengaged state when powered off. When the electromagnetic clutch is engaged, the rotor of the air-conditioning compressor can be directly mechanically connected to the rotor of the driving motor. The air-conditioning compressor is electrically connected to the battery through an air-conditioning controller. When the electromagnetic clutch does not need to be started, the air-conditioning controller supplies power to the motor自带 by the air-conditioning compressor to control the operation of the air-conditioning compressor. During the driving of the vehicle, the driving motor of the driving wheels is electrically connected to the battery through a motor controller, and the motor controller can control the operation of the driving motor. A temperature sensor is also provided in the battery to detect the temperature inside the battery in real time. The temperature sensor is electrically connected to the central controller and transmits the temperature signal to the central controller. The brake light switch is connected to the driver's brake pedal. When the brake pedal is depressed, the brake light switch is turned on, causing the brake lights to light up. Therefore, the activation of the brake light switch means that the driver has depressed the brake pedal, indicating that the vehicle is in the braking state. The brake light switch, temperature sensor, air-conditioning controller, motor controller, battery, and electromagnetic clutch are respectively electrically connected to the central controller. The brake light switch and temperature sensor transmit their respective signals to the central controller, and the central controller controls the operation of the air-conditioning controller, motor controller, and electromagnetic clutch.

[0038] As Figure 2 shown, the electric vehicle air-conditioning control method in the present invention includes:

[0039] (1) The central controller is turned on, and the working mode of the air conditioner is judged by communicating with the air-conditioning controller;

[0040] (2) If the air conditioner does not start at this time, return to step (1), and the central controller continues to communicate with the air-conditioning controller, continuously collecting the signals sent by it to judge the change of the working mode of the air conditioner;

[0041] (3) If the air conditioner is in the heating mode, the central controller collects the signal of the temperature sensor and judges the range where the temperature T of the battery is located;

[0042] 1) If T < T1, where T1 is the lower limit value of the normal operating temperature range of the battery, it indicates that the battery temperature is lower than the normal operating temperature at this time, the charge and discharge efficiency of the battery is lower, and the energy loss is greater during the charge and discharge process. The central controller collects the signal of the brake light switch;

[0043] ① If the brake light switch is turned on, indicating that the vehicle is in the braking state at this time, the electromagnetic clutch is engaged, so that the rotor of the air-conditioning compressor is mechanically connected to the rotor of the driving motor, directly transferring the kinetic energy of the vehicle to the rotor of the air-conditioning compressor to drive the air-conditioning compressor to work. At the same time, the air-conditioning controller cuts off the power supply of the battery to the motor自带 by the air-conditioning compressor;

[0044] ② If the brake light switch is off, indicating that the car is not braking at this time, the electromagnetic clutch will be disengaged and the air conditioning controller will use the battery to power the air conditioning compressor's own motor to drive the air conditioning compressor to work normally for heating;

[0045] 2) If T≥T1, it indicates that the battery is within the normal operating temperature range and the battery charging and discharging efficiency is higher. At this time, the electromagnetic clutch is disengaged. Regardless of whether the car is braking or not, the air conditioning controller uses the battery to power the air conditioning compressor's own motor to drive the air conditioning compressor for normal heating work;

[0046] 3) Return to step (1).

[0047] (4) If the air conditioner is in cooling mode, the central controller collects the signal from the temperature sensor and determines the range of the battery temperature T;

[0048] 1) If T>T2, the central controller collects the signal of the brake light switch. T2 is the upper limit of the normal operating temperature range of the battery, indicating that the battery temperature is higher than the normal operating temperature at this time. The battery is seriously heated and the charging and discharging process will cause greater heat generation, which will further increase the battery temperature, damage the battery or cause the battery to spontaneously combust, and reduce the battery charging and discharging efficiency. At this time, the number and frequency of battery charging and discharging should be reduced;

[0049] ① If the brake light switch is turned on, indicating that the car is in braking state, the electromagnetic clutch is engaged, so that the rotor of the air-conditioning compressor is mechanically connected with the rotor of the driving motor, and the kinetic energy of the car is directly transferred to the rotor of the air-conditioning compressor to drive the air-conditioning compressor to work. At the same time, the air-conditioning controller cuts off the battery's power supply to the motor of the air-conditioning compressor;

[0050] ② If the brake light switch is off, indicating that the car is not braking at this time, the electromagnetic clutch will be disengaged and the air conditioning controller will use the battery to power the air conditioning compressor's own motor to drive the air conditioning compressor to work normally;

[0051] 2) If T≤T2, it indicates that the battery is within the normal operating temperature range and the battery charging and discharging efficiency is higher. At this time, the electromagnetic clutch is disengaged. Regardless of whether the car is braking or not, the air conditioning controller uses the battery to power the air conditioning compressor's own motor to drive the air conditioning compressor for normal cooling work;

[0052] 3) Return to step (1).

[0053] Embodiment 2

[0054] Compared with the first embodiment, the electric vehicle air conditioning control system in this embodiment adds a brake pressure sensor, such as Figure 7As shown in the figure. The brake pressure sensor is installed inside the master brake cylinder and is used to monitor the oil pressure inside the master brake cylinder, that is, the brake fluid pressure (i.e., the brake pressure) generated by the driver's brake pedal. This brake fluid pressure also represents the braking force on the wheel brakes. That is, the value of the brake pressure sensor represents the value of the braking force generated by the driver's brake pedal on the wheels, and the two are in a proportional relationship. The brake pressure sensor is electrically connected to the central controller and transmits the brake pressure signal to the central controller.

[0055] As Figure 3 shown, the electric vehicle air-conditioning control method in this embodiment includes:

[0056] (1) The central controller is turned on, and it determines the working mode of the air conditioner by communicating with the air-conditioning controller;

[0057] (2) If the air conditioner does not start at this time, it returns to step (1), and the central controller continues to communicate with the air-conditioning controller, continuously collecting the signals it sends to determine changes in the air-conditioning working mode;

[0058] (3) If the air conditioner is in the heating mode, the central controller collects the signals of the temperature sensor and determines the range where the temperature T of the battery is located;

[0059] 1) If T < T1, where T1 is the lower limit value of the normal operating temperature range of the battery, it indicates that the battery temperature is lower than the normal operating temperature at this time, the charge and discharge efficiency of the battery is lower, and the energy loss is greater during the charge and discharge process;

[0060] ① If the brake light switch is turned on, indicating that the vehicle is in the braking state at this time, the electromagnetic clutch should be engaged or engaged for a part of the time, so that the rotor of the air-conditioning compressor is mechanically connected to the rotor of the driving motor, directly transferring the kinetic energy of the vehicle to the rotor of the air-conditioning compressor to drive the air-conditioning compressor to work. At the same time, the air-conditioning controller cuts off the power supply of the battery to the self-owned motor of the air-conditioning compressor; and the central controller collects the signals of the brake pressure sensor;

[0061] (i) If the brake pressure P measured by the brake pressure sensor < P1, where P1 is 30% of the maximum brake pressure of the master brake cylinder, it means that the brake pressure generated at this time is relatively small, and the driver's intention is to lightly step on the brake pedal; then the central controller controls the engagement process of the electromagnetic clutch in a duty cycle manner, so that the engagement rate Q = 0.3;

[0062] The duty cycle refers to the proportion of the energization time relative to the total time within a pulse cycle. As Figure 4As shown, in the output voltage signal of the central controller for the electromagnetic clutch, within each time period, the voltage remains at the voltage U that causes the electromagnetic clutch to be in the engaged state for only 30% of the time, and the voltage is 0 for the remaining 70% of the time. As a result, within each time period, the electromagnetic clutch is in the engaged state for only 30% of the time, and the electromagnetic clutch is in the disengaged state for the remaining 70% of the time. Then, the engagement rate Q of the electromagnetic clutch is 0.3. Similarly, as Figure 5 shown, within each time period, the voltage remains at the voltage U that causes the electromagnetic clutch to be in the engaged state for only 70% of the time, and the voltage is 0 for the remaining 30% of the time. Then, the engagement rate Q of the electromagnetic clutch is 0.7. Similarly, as Figure 6 shown, within each time period, the voltage remains at the voltage U that causes the electromagnetic clutch to be in the engaged state for 100% of the time. Then, the engagement rate Q of the electromagnetic clutch is 1. As a preference, each time period is 0.1 second.

[0063] (ii) If the braking pressure P1 ≤ P < P2 measured by the braking pressure sensor at this time, where P2 is 60% of the maximum braking pressure of the master cylinder, it indicates that the braking pressure generated at this time is moderate and the driver steps on the brake pedal with medium intensity. Then, the central controller controls the engagement process of the electromagnetic clutch in a duty cycle manner to make the engagement rate Q = 0.7, as Figure 5 shown;

[0064] (iii) If the braking pressure P ≥ P2 measured by the braking pressure sensor at this time, it indicates that the braking pressure generated at this time is closer to the maximum value and the driver steps on the brake pedal with high intensity. Then, the central controller controls the engagement process of the electromagnetic clutch in a duty cycle of 100% to make the engagement rate Q = 1, as Figure 6 shown.

[0065] ② If the brake lamp switch is off, it indicates that the vehicle is not braking at this time. Then, the electromagnetic clutch disengages and disconnects, and the air conditioner controller uses the battery to supply power to the motor自带 by the air conditioner compressor to drive the normal heating operation of the air conditioner compressor;

[0066] 2) If T ≥ T1, it indicates that the battery is within the normal operating temperature range and the charge-discharge efficiency of the battery is higher. At this time, the electromagnetic clutch is disengaged and disconnected. Whether the vehicle is braking or not, the air conditioner controller uses the battery to supply power to the motor自带 by the air conditioner compressor to drive the normal heating operation of the air conditioner compressor;

[0067] 3) Return to step (1).

[0068] (4) If the air conditioner is in the cooling mode, the central controller collects the signal of the temperature sensor and judges the range where the temperature T of the battery is located;

[0069] 1) If T > T2, the central controller collects the signal of the brake lamp switch. T2 is the upper limit value of the normal operating temperature range of the battery, indicating that the battery temperature is higher than the normal operating temperature at this time. The battery generates a large amount of heat, and the charging and discharging process will cause even more heat generation, further increasing the battery temperature, damaging the battery or causing the battery to catch fire spontaneously, and reducing the charging and discharging efficiency of the battery. At this time, the charging and discharging times and frequencies of the battery should be reduced;

[0070] ① If the brake lamp switch is turned on, indicating that the vehicle is in the braking state at this time, the electromagnetic clutch engages or engages for part of the time, mechanically connecting the rotor of the air-conditioning compressor to the rotor of the driving motor, directly transmitting the kinetic energy of the vehicle to the rotor of the air-conditioning compressor, driving the air-conditioning compressor to work, and at the same time the air-conditioning controller cuts off the power supply of the battery to the self-owned motor of the air-conditioning compressor; and the central controller collects the signal of the brake pressure sensor;

[0071] (i) If the brake pressure P measured by the brake pressure sensor at this time is < P1, where P1 is 30% of the maximum brake pressure of the master cylinder, it means that the brake pressure generated at this time is relatively small and the driver's intention is to lightly step on the brake pedal; then the central controller controls the engagement process of the electromagnetic clutch in a duty cycle manner, so that the engagement rate Q = 0.3, as Figure 4 shown;

[0072] (ii) If the brake pressure P measured by the brake pressure sensor at this time satisfies P1 ≤ P < P2, where P2 is 60% of the maximum brake pressure of the master cylinder, it means that the brake pressure generated at this time is moderate and the driver steps on the brake pedal with medium intensity. Then the central controller controls the engagement process of the electromagnetic clutch in a duty cycle manner, so that the engagement rate Q = 0.7, as Figure 5 shown;

[0073] (iii) If the brake pressure P measured by the brake pressure sensor at this time is ≥ P2, indicating that the brake pressure generated at this time is closer to the maximum value and the driver steps on the brake pedal with high intensity, then the central controller controls the engagement process of the electromagnetic clutch in a duty cycle of 100%, so that the engagement rate Q = 1, as Figure 6 shown.

[0074] ② If the brake lamp switch is turned off, indicating that the vehicle is not braking at this time, the electromagnetic clutch disengages and disconnects, and the air-conditioning controller uses the battery to supply power to the self-owned motor of the air-conditioning compressor to drive the normal refrigeration operation of the air-conditioning compressor;

[0075] 2) If T ≤ T2, indicating that the battery is within the normal operating temperature range and the charging and discharging efficiency of the battery is higher. At this time, the electromagnetic clutch disengages and disconnects. Whether the vehicle is braking or not, the air-conditioning controller uses the battery to supply power to the self-owned motor of the air-conditioning compressor to drive the normal refrigeration operation of the air-conditioning compressor;

[0076] 3) Return to step (1).

[0077] In the second embodiment, the engagement rate of the electromagnetic clutch is controlled according to different braking pressure ranges. The reason is that after the electromagnetic clutch is engaged, the vehicle driving motor will superimpose the rotational resistance torque of the air-conditioning compressor rotor on the basis of the resistance torque generated by the original braking energy recovery, so that the braking force transmitted from the driving motor to the wheels increases rapidly, that is, a greater braking deceleration is generated, which has an adverse impact on the riding comfort of the passengers in the vehicle. Especially when the driver lightly presses the brake pedal and only requires a small braking force, the impact on the riding comfort is more obvious. Therefore, it is necessary to adjust the rotational resistance torque transmitted from the air-conditioning compressor rotor to the driving motor according to the depth and intensity of the driver stepping on the brake pedal or the value of the braking force required by the driver, so that the rotational resistance torque increases as the braking force required by the driver increases. In addition, the rotational resistance torque of the air-conditioning compressor rotor superimposed on the driving motor increases with the increase of the engagement rate of the electromagnetic clutch. When the driver lightly presses the brake pedal, the engagement rate Q of the electromagnetic clutch is 0.3 to improve the riding comfort; when the driver moderately presses the brake pedal, the engagement rate Q of the electromagnetic clutch is 0.7, which not only ensures a certain riding comfort but also improves the utilization efficiency of the braking recovered energy; when the driver strongly presses the brake pedal, the engagement rate of the electromagnetic clutch is at the maximum value Q = 1, which not only fully converts the kinetic energy of the vehicle directly into the kinetic energy of the rotor of the air-conditioning compressor and has the highest utilization efficiency of the braking recovered energy, but also makes the rotational resistance torque of the air-conditioning compressor rotor superimposed on the driving motor the largest, so that the driving motor generates the maximum braking force on the wheels and helps the driver stop the vehicle as soon as possible.

[0078] In the two embodiments of the present invention, when the air conditioner is in the heating mode, the outside air temperature is much lower than the normal body temperature of the human body. During battery operation, even if its temperature T exceeds T1, it is very difficult to exceed the upper limit value T2 of the normal operating temperature of the battery. Therefore, only the case where the battery temperature T < T1 is considered at this time. Similarly, when the air conditioner is in the cooling mode, the outside air temperature is close to or exceeds the normal body temperature of the human body. During battery operation, even if its temperature T is lower than T2, it is very difficult to be lower than the lower limit value T1 of the normal operating temperature of the battery. Therefore, only the case where the battery temperature T > T2 is considered at this time. Generally, T1 = -4°C and T2 = 60°C.

Claims

1. A method for controlling air conditioning of an electric vehicle, characterized in that It includes the following steps: (1) Use the central controller set inside the vehicle to collect the signals of the temperature sensors in the battery; (2) When the air conditioner starts, determine the working mode of the air conditioner. 1) When the air conditioner is in the heating mode, if the relationship between the temperature T of the battery and the lower limit value T1 of the normal working temperature range of the battery is T < T1 and the brake lamp switch is not turned on, or the temperature T of the battery is T ≥ T1, then the electromagnetic clutch connecting the air conditioner compressor and the rotor of the driving wheel driving motor is disengaged; if the temperature T of the battery is T < T1 and the brake lamp switch is turned on, then the electromagnetic clutch is energized and engaged. 2) When the air conditioner is in the cooling mode, if the relationship between the temperature T of the battery and the upper limit value T2 of the normal working temperature range of the battery is T > T2 and the brake lamp switch is not turned on, or the temperature T of the battery is T ≤ T2, then the electromagnetic clutch is disengaged; if the temperature T of the battery is T > T2 and the brake lamp switch is turned on, then the electromagnetic clutch is energized and engaged. (3) Return to step (1); When the electromagnetic clutch meets the condition to be energized and engaged, determine the relationship between the braking pressure P measured by the brake pressure sensor set inside the vehicle and the set values P1 and P2; ① When the braking pressure P < P1, the engagement rate Q of the electromagnetic clutch = 0.3; ② When the braking pressure P1 ≤ P < P2, the engagement rate Q of the electromagnetic clutch = 0.7; ③ When the braking pressure P ≥ P2, the engagement rate Q of the electromagnetic clutch = 1.

2. The electric vehicle air conditioner control method according to claim 1, wherein: P1 is 30% of the maximum braking pressure of the master cylinder, and P2 is 60% of the maximum braking pressure of the master cylinder.

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