Hybrid electric vehicle low temperature starting control method and control system

Abstract

The present invention provides a hybrid electric vehicle low temperature starting control method and control system. The control method of the present invention is to power on the power battery BMS after the whole vehicle is started, and obtain the temperature of the power battery; when the temperature of the power battery is below the preset temperature threshold, put the high-voltage component connected to the power battery in a non-working mode, and then start the engine; keep the high-voltage component in the non-working mode, and continue to obtain the temperature of the power battery; when the temperature of the power battery is greater than the preset temperature threshold, control the high-voltage component to enter the working mode. The hybrid electric vehicle low temperature starting control method described in the present invention can put the high-voltage component connected to the power battery in a non-working mode when the power battery temperature is low and the power battery is in an operating range where discharge is not allowed, thereby reducing the risk of charging and discharging the power battery and improving the safety performance of the vehicle.

Description

Technical Field

[0001] The present invention relates to the field of automobile technology, and in particular to a hybrid electric vehicle low-temperature starting control method and a hybrid electric vehicle low-temperature starting control system capable of executing the control method. Background Art

[0002] The 48V P0 hybrid system is a vehicle model that has a motor installed at the front end of the engine, which is connected to the engine crankshaft through a belt and equipped with a P0 motor. This vehicle model can realize automatic engine start and stop, braking, coasting energy recovery and auxiliary power output when waiting for a red light.

[0003] The 48V P0 hybrid system is equipped with a 48V power battery and a traditional 12V battery. The 12V battery is responsible for powering traditional loads such as lighting, ignition, entertainment and audio systems; the 48V power battery supplies power to high-voltage components such as DC / DC converters and BSG (Belt-Driven Starter Generator, an all-in-one machine that uses belt drive to take into account both starting and power generation) motors, realizing functions such as intelligent start-stop, power assistance and energy recovery.

[0004] In the 48V P0 hybrid system, in order to ensure that the 48V power battery and the 12V battery operate near the target power, the working principles of the high and low voltage network components are very clear. The 12V power supply system provides the required power to the low voltage network through the DC / DC converter and the 12V battery to ensure the normal operation of the vehicle's low voltage network. In the energy recovery and BSG motor power generation functions, the BSG motor supplies power to the low voltage load through the DC / DC converter. When the BSG motor generates insufficient power or does not generate power, the 48V power battery supplies power to the low voltage load through the DC / DC converter. The 12V battery supplies power to the low voltage load when the DC / DC converter is insufficient or unavailable.

[0005] Currently, the 48V power battery used in models equipped with a 48V P0 hybrid system supports responding to power-on requests and closing relays above -39 degrees. However, the 48V battery has no charge and discharge capabilities between -39 degrees and -35 degrees, and the charge and discharge current limits are both 0. However, after the relay is closed, the DC / DC converter is in working mode or the BSG motor is in torque mode, which may cause passive discharge of the battery, adversely affecting the life of the 48V power battery, and in severe cases, it may affect the risk of battery short circuit or fire. Summary of the invention

[0006] In view of this, the present invention aims to provide a low-temperature starting control method and control system for a hybrid electric vehicle, so as to improve the safety of low-temperature starting of the vehicle.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0008] A hybrid electric vehicle low temperature starting control method, the control method comprising:

[0009] After the vehicle is started, the power battery BMS (BATTERY MANAGEMENT SYSTEM) is powered on and the temperature of the power battery is obtained;

[0010] When the acquired temperature of the power battery is below a preset temperature threshold, placing a high-voltage component connected to the power battery in a non-operating mode;

[0011] After all of the high-voltage components are in the non-operating mode, starting the engine;

[0012] After the engine is started, keeping the high-voltage component in the non-operating mode and continuously acquiring the temperature of the power battery;

[0013] When the acquired temperature of the power battery is greater than the preset temperature threshold, the high-voltage component is enabled to enter a working mode.

[0014] Furthermore, after the whole vehicle is started, the power battery BMS is powered on, including: when the whole vehicle is started, sending a power battery BMS power-on request; after receiving the power battery BMS power-on request, closing the power battery BMS relay to power on the power battery BMS.

[0015] Furthermore, starting the engine after all of the high-voltage components are in the non-working mode includes: when all of the high-voltage components are in the non-working mode and the power battery BMS is powered on, using a battery to start the engine.

[0016] Furthermore, after the step of placing the high-voltage component connected to the power battery in a non-operating mode, the method further includes: when the high-voltage component is in the non-operating mode, limiting the vehicle speed to be lower than a preset speed threshold.

[0017] Furthermore, after the step of placing the high-voltage component connected to the power battery in a non-operating mode, the method further includes: when the high-voltage component is in the non-operating mode, displaying prompt information associated with the high-voltage component.

[0018] Furthermore, the high voltage components include a BSG motor and a DC / DC converter.

[0019] Furthermore, after the BSG motor enters the working mode, it also includes: requesting BSG torque according to the charging and discharging power of the power battery.

[0020] Furthermore, the preset temperature threshold is -35°C.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] The hybrid vehicle low-temperature starting control method described in the present invention can reduce the risk of causing the power battery to generate charging and discharging currents by placing the high-voltage components connected to the power battery in a non-operating mode when the power battery temperature is low and the power battery is in an operating range where discharge is not allowed, and can more reliably ensure that the power battery has no charging current or discharging current, thereby improving the safety performance of the vehicle.

[0023] Another object of the present invention is to provide a hybrid electric vehicle low temperature starting control system, the control system includes a vehicle controller, and a power battery temperature acquisition module connected to the vehicle controller, and the vehicle controller has a power battery BMS power-on module, a high-voltage component control module and an engine starting module, wherein:

[0024] The power battery BMS power-on module is used to power on the power battery BMS after the vehicle is started;

[0025] The power battery temperature acquisition module is used to obtain the temperature of the power battery;

[0026] The high-voltage component control module is used to place the high-voltage component connected to the power battery in a non-operating mode when the acquired temperature of the power battery is below a preset temperature threshold;

[0027] The engine starting module is used to start the engine after the high-voltage component is in the non-operating mode;

[0028] The high-voltage component control module is further used to keep the high-voltage component in the non-operating mode after the engine is started, and to control the high-voltage component to enter the operating mode after the acquired temperature of the power battery is greater than the preset temperature threshold.

[0029] Furthermore, the vehicle controller also has a speed limit module, and the control system also includes a display module, wherein:

[0030] The vehicle speed limiting module is used to limit the vehicle speed to be lower than a preset speed threshold when the high-voltage component is in the non-operating mode;

[0031] The display module is used to display prompt information associated with the high-voltage component when the high-voltage component is in the non-operating mode.

[0032] The hybrid electric vehicle low temperature starting control system of the present invention has the same beneficial effects as the aforementioned hybrid electric vehicle low temperature starting control method, which will not be described in detail herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0034] Figure 1 A schematic diagram of the structure of a hybrid vehicle power system according to an embodiment of the present invention;

[0035] Figure 2 A schematic diagram of the structure of a low-temperature starting control system for a hybrid electric vehicle according to an embodiment of the present invention;

[0036] Figure 3 The present invention is a flowchart of a hybrid vehicle low-temperature starting control method according to an embodiment of the present invention.

[0037] Description of reference numerals:

[0038] 1. Vehicle controller; 2. Battery; 3. DC / DC converter; 4. Power battery; 5. Engine; 6. BSG motor; 7. Gearbox; 8. Driving wheel; 9. Power battery temperature acquisition module; 10. Display module;

[0039] 101. Power battery BMS power-on module; 102. High-voltage component control module; 103. Engine start module; 104. Vehicle speed limit module;

[0040] 301. DC / DC controller; 401. Battery management system; 601. BSG motor controller. DETAILED DESCRIPTION

[0041] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0042] In the description of the present invention, unless otherwise clearly defined, the terms "installation", "connection", "connection", and "connector" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood in combination with specific circumstances.

[0043] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0044] The present embodiment relates to a low-temperature starting control method for a hybrid electric vehicle. The method is to power on the power battery BMS after the whole vehicle is started, and when the temperature of the power battery 4 obtained is below a preset temperature threshold, put the high-voltage component connected to the power battery 4 in a non-working mode, and start the engine 5; and keep the high-voltage component in the non-working mode, and control the high-voltage component to enter the working mode after the temperature of the power battery 4 obtained is greater than the preset temperature threshold.

[0045] In order to facilitate a better understanding of the control method of this embodiment, the structure of the hybrid vehicle power system described in the embodiment of the present invention is first described below.

[0046] like Figure 1 As shown, it mainly includes a vehicle controller 1, a battery 2 that can communicate with the vehicle controller 1, a DC / DC controller 301, a battery management system 401 and a BSG motor controller 601. The DC / DC controller 301 is connected to the DC / DC converter 3, the battery management system 401 is connected to the 48V power battery 4, the BSG motor controller 601 is connected to the BSG motor 6, and the power battery 4, the DC / DC converter 3 and the BSG motor 6 are connected to each other.

[0047] Among them, the battery 2 of this embodiment is preferably an existing 12V battery 2, which can be connected to the engine 5 and used to start the engine 5. Since the engine 5 is connected to the gearbox 7 and the drive wheel 8 in sequence, the 12V battery 2 can be used to power the vehicle to be in driving mode.

[0048] It should be noted that the voltages of the storage battery 2 and the power battery 4 may be other voltages in addition to the above voltages, but this may result in incompatibility with the voltages of other components.

[0049] Next, refer to Figure 2 The control system that can execute the low-temperature starting control method of the hybrid electric vehicle of this embodiment is described. It mainly includes a vehicle controller 1, and a power battery temperature acquisition module 9 and a display module 10 connected to the vehicle controller 1, and the vehicle controller 1 has a power battery BMS power-on module 101, a high-voltage component control module 102, an engine starting module 103 and a vehicle speed limit module 104.

[0050] The power battery BMS power-on module 101 is used to power on the power battery BMS, and the engine start module 103 is used to start the engine 5. The power battery temperature acquisition module 9 is used to obtain the temperature of the power battery 4, and it can use a temperature sensor set in the power battery.

[0051] In addition, in the above structure, the high-voltage component control module 102 is used to place the high-voltage component connected to the power battery 4 in a non-working mode, or to keep the high-voltage component in a non-working mode after the engine 5 is started, and to control the high-voltage component to enter a working mode.

[0052] It should be noted that, in this embodiment, the BSG motor 6 and the DC / DC converter 3 constitute the high-voltage component of this embodiment, and the BSG motor controller 601 and the DC / DC controller 301 constitute the high-voltage component control module of this embodiment. However, it should be understood that if the control system of the vehicle includes other electrical components connected to the power battery 4, the electrical components connected to the power battery 4 should also be controlled to be in a non-operating mode to effectively prevent the power battery 4 from charging and discharging.

[0053] Specifically in this embodiment, when the temperature of the power battery 4 is lower than the preset temperature threshold, in response to the control signals of the DC / DC controller 301 and the BSG motor controller 601, the DC / DC converter 3 and the BSG motor 6 can be placed in a non-working mode, and when the temperature of the power battery 4 is greater than the preset temperature threshold, in response to the control signals of the DC / DC controller 301 and the BSG motor controller 601, the DC / DC converter 3 and the BSG motor 6 can remain in the non-working mode, or enter the working mode.

[0054] In addition, in the hybrid vehicle cold start control system of this embodiment, the speed limit module 104 is used to limit the vehicle speed to a preset speed threshold when the high-voltage component is in a non-operating mode, so as to effectively ensure driving safety. The display module 10 is used to display the prompt information associated with the high-voltage component when it is in a non-operating mode, so as to timely remind the driver to pay attention to driving safety. In specific implementation, the display module 10 can be a dashboard or a central control screen on the vehicle.

[0055] The hybrid vehicle low temperature starting control method of this embodiment is combined with Figure 3 As shown, it specifically includes the following steps:

[0056] s101. After the vehicle is started, the power battery BMS is powered on and the temperature of the power battery 4 is obtained.

[0057] In this step, the vehicle controller 1 controls the power battery BMS to close the relay to power on the power battery 4 .

[0058] s102. When the acquired temperature of the power battery 4 is below a preset temperature threshold, the high-voltage components connected to the power battery are placed in a non-operating mode.

[0059] In this step, the high-voltage components refer to the BSG motor 6 and the DC / DC converter 3. When the temperature of the power battery 4 is below -35°C, the vehicle controller 1 controls the BSG motor 6 to enter the Neutral working mode; the vehicle controller 1 also controls the DC / DC converter 3 to enter the standby working mode.

[0060] s103. After all high-voltage components are in non-operating mode, start the engine 5.

[0061] In this step, the vehicle controller 1 selects the battery 2 to start the engine 5 .

[0062] s104. After the engine 5 is started, the high-voltage components are kept in a non-operating mode, and the temperature of the power battery 4 is continuously acquired.

[0063] In this step, the high-voltage components refer to the BSG motor 6 and the DC / DC converter 3, and the BSG motor 6 and the DC / DC converter 3 still remain in the non-working mode, that is, the BSG motor 6 maintains the Neutral working mode, and the DC / DC converter 3 maintains the standby working mode.

[0064] In addition, in this step, the vehicle speed is restricted to a certain extent, that is, the vehicle is traveling within a range below the preset speed threshold, and a warning message "power battery 4 temperature is low, power system limited" is displayed to remind the driver to drive slowly.

[0065] s105. When the acquired temperature of the power battery 4 is greater than a preset temperature threshold, the high voltage component enters a working mode.

[0066] In this step, when the power battery 4 is heated to above -35 degrees, the vehicle controller 1 requests the DC / DC converter 3 to enter the buck working mode, requests the BSG motor 6 to enter the torque working mode, and requests the BSG torque according to the charging and discharging power of the power battery 4.

[0067] In the above steps, the non-operating mode of the BSG motor 6 is the Neutral mode; the operating mode of the BSG motor 6 is the torque mode; the non-operating mode of the DC / DC converter 3 is the standby mode; and the operating mode of the DC / DC converter 3 is the buck mode.

[0068] In the low-temperature starting control method for a hybrid electric vehicle of this embodiment, when the temperature is below -35 degrees, since the BMS current limit is 0, the BSG motor 6 and the DC / DC converter 3 are both in non-operating mode and cannot provide power to the 12V low-voltage load, and the entire vehicle is in a state where the battery 2 supplies power to the entire vehicle.

[0069] In addition, the low-temperature starting control method for a hybrid electric vehicle in this embodiment is to place all high-voltage components such as the DC / DC converter 3 and the BSG motor 6 in a non-operating state within the working range where the power battery 4 is not allowed to charge and discharge, so as to prevent all risks that may cause the power battery to generate charging and discharging currents.

[0070] Compared with other solutions such as prohibiting the power-on start of the engine 5 below -35°C, making it impossible to drive, or only reserving power and limiting torque, but the BSG is still in torque mode, this method can not only meet the power demand of the whole vehicle, but also more reliably ensure that no charging current or discharging current is generated in the power battery 4, so that driving needs and component protection are optimally controlled.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A low temperature starting control method for a hybrid electric vehicle, characterized in that: The control method includes: After the vehicle is started, the power battery BMS is powered on and the temperature of the power battery (4) is obtained; When the acquired temperature of the power battery (4) is below a preset temperature threshold, placing a high-voltage component connected to the power battery in a non-operating mode; After all of the high-voltage components are in the non-operating mode, starting the engine (5); After the engine (5) is started, the high-voltage component is kept in the non-operating mode, and the temperature of the power battery (4) is continuously acquired; When the acquired temperature of the power battery (4) is greater than the preset temperature threshold, the high-voltage component is put into a working mode.

2. The hybrid vehicle low temperature starting control method according to claim 1, characterized in that: After the vehicle is started, the power battery BMS is powered on, including: When the vehicle is started, a power-on request is sent to the power battery BMS; After receiving the power battery BMS power-on request, the power battery BMS relay is closed to power on the power battery BMS.

3. The hybrid vehicle low temperature starting control method according to claim 2, characterized in that: After all the high-voltage components are in the non-operating mode, starting the engine (5) comprises: When all the high-voltage components are in the non-operating mode and the power battery BMS is powered on, the battery (2) is used to start the engine (5).

4. The hybrid vehicle low temperature starting control method according to claim 1, characterized in that: After the step of placing the high-voltage component connected to the power battery (4) in a non-operating mode, the method further comprises: When the high-voltage component is in the non-operating mode, the vehicle speed is limited to be lower than a preset speed threshold.

5. The hybrid vehicle low temperature starting control method according to claim 4, characterized in that: After the step of placing the high-voltage component connected to the power battery (4) in a non-operating mode, the method further comprises: When the high-voltage component is in the non-operating mode, prompt information associated therewith is displayed.

6. The hybrid vehicle low temperature starting control method according to claim 1, characterized in that: The high voltage component comprises: BSG motor (6) and DC / DC converter (3).

7. The hybrid vehicle low temperature starting control method according to claim 6, characterized in that: After the BSG motor (6) enters the working mode, it also includes: The BSG torque is requested according to the charging and discharging power of the power battery (4).

8. The hybrid vehicle low temperature starting control method according to any one of claims 1 to 7, characterized in that: The preset temperature threshold is -35°C.

9. A hybrid electric vehicle low temperature starting control system, characterized in that: The control system comprises a vehicle controller (1) and a power battery (4) temperature acquisition module (9) connected to the vehicle controller (1), and the vehicle controller (1) comprises a power battery BMS power-on module (101), a high-voltage component control module (102) and an engine starting module (103), wherein: The power battery BMS power-on module (101) is used to power on the power battery BMS after the vehicle is started; The power battery (4) temperature acquisition module (9) is used to acquire the temperature of the power battery (4); The high-voltage component control module (102) is used to place the high-voltage component connected to the power battery (4) in a non-operating mode when the acquired temperature of the power battery (4) is below a preset temperature threshold; The engine starting module (103) is used to start the engine (5) after the high-voltage component is in the non-operating mode; The high-voltage component control module (102) is also used to keep the high-voltage component in the non-operating mode after the engine (5) is started, and to control the high-voltage component to enter the operating mode after the acquired temperature of the power battery (4) is greater than the preset temperature threshold.

10. The hybrid vehicle low temperature starting control system according to claim 9, characterized in that: The vehicle controller (1) further comprises a vehicle speed limiting module (104), and the control system further comprises a display module (10), wherein: The vehicle speed limiting module (104) is used to limit the vehicle speed to be lower than a preset speed threshold when the high-voltage component is in the non-operating mode; The display module (10) is used to display prompt information associated with the high-voltage component when the high-voltage component is in the non-operating mode.

Images