A method, system, and range-extended electric vehicle for low-temperature starting

Abstract

This invention discloses a low-temperature starting method, system, and range-extended electric vehicle. The method includes: in response to a start signal from the range-extended electric vehicle, acquiring the temperature information of the range-extended electric vehicle; using the temperature information to determine whether the range-extended electric vehicle is in a low-temperature state; when the range-extended electric vehicle is in a low-temperature state, selecting a calculation logic for calculating engine start parameters based on the actual vehicle speed of the range-extended electric vehicle, and calculating the corresponding start parameters according to the selected calculation logic; starting the engine according to the calculated start parameters, thereby indirectly increasing the temperature of the power battery of the range-extended electric vehicle by increasing the circulating water temperature of the water circulation network; wherein the engine and the power battery share the water circulation network.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, and in particular to a low-temperature starting method, system, and range-extended electric vehicle. Background Technology

[0002] An extended-range electric vehicle (REV) is an electric vehicle with a dual power system. Unlike a typical pure electric vehicle, it is equipped with not only a motor and battery, but also an engine. The engine can generate electricity to provide power to the battery pack and additional power. Therefore, the vehicle's maximum output capacity depends on the battery's maximum discharge power plus the engine's output power.

[0003] Because the maximum discharge power of a battery is greatly affected by the temperature of the power battery, the lower the temperature of the power battery, the lower the maximum discharge power, especially in low-temperature conditions where the maximum discharge power will decrease sharply. When a range-extended electric vehicle has been submerged in low-temperature outdoor conditions for a period of time, if it is still in pure electric operation mode, the power output will be significantly limited when it is first powered on and driven.

[0004] Therefore, the problem with existing technology is that it cannot quickly increase the maximum discharge power of the battery under low temperature conditions, thus affecting the power output of range-extended electric vehicles. Summary of the Invention

[0005] This invention provides a low-temperature starting method, system, and range-extended electric vehicle. When the range-extended electric vehicle is detected to be driving at low water temperature, the system selects the corresponding calculation logic based on the actual vehicle speed to calculate the target power generation and target speed required to start the engine, and starts the engine accordingly. This indirectly increases the temperature of the power battery of the range-extended electric vehicle by raising the circulating water temperature, thereby solving or partially solving the technical problem that the maximum discharge power of the battery cannot be quickly increased under low temperature conditions, thus affecting the power output of the range-extended electric vehicle.

[0006] To address the aforementioned technical problems, a first aspect of the present invention discloses a low-temperature starting method for a range-extended electric vehicle, the method comprising:

[0007] In response to the start signal of the range-extended electric vehicle, the temperature information of the range-extended electric vehicle is acquired;

[0008] The temperature information is used to determine whether the range-extended electric vehicle is in a low-temperature state.

[0009] When the range-extended electric vehicle is in a low-temperature state, the calculation logic for calculating engine starting parameters is selected according to the actual speed of the range-extended electric vehicle, and the corresponding starting parameters are calculated according to the selected calculation logic.

[0010] The engine is started according to the calculated starting parameters to indirectly increase the temperature of the power battery of the range-extended electric vehicle by increasing the circulating water temperature of the water circulation network; wherein the engine and the power battery share the water circulation network.

[0011] Optionally, the temperature information includes: the coolant temperature at the moment the engine starts, and the current actual coolant temperature of the vehicle; the step of using the temperature information to determine whether the range-extended electric vehicle is in a low-temperature state specifically includes:

[0012] The maximum water temperature limit is determined using the water temperature at the moment of engine startup.

[0013] The engine coolant temperature at startup is detected using an engine coolant temperature threshold, and the current vehicle coolant temperature is detected using the maximum coolant temperature limit.

[0014] When the engine coolant temperature is lower than the engine coolant temperature threshold at the time of engine startup, and the current actual coolant temperature of the vehicle is lower than the maximum coolant temperature limit, it is determined that the range-extended electric vehicle is in a low-temperature state.

[0015] Optionally, after starting the engine according to the calculated starting parameters, the method further includes:

[0016] The actual water temperature of the current vehicle is detected in real time using the maximum water temperature limit.

[0017] If the current actual water temperature of the vehicle remains above the maximum water temperature limit for a set period of time, the engine will be shut down.

[0018] Optionally, the computation logic includes a first computation logic and a second computation logic;

[0019] The calculation logic for selecting the engine starting parameters based on the actual speed of the range-extended electric vehicle specifically includes:

[0020] When the actual vehicle speed equals a set threshold, the first calculation logic is selected to calculate the start-up parameters.

[0021] When the actual vehicle speed is greater than the set threshold, the second calculation logic is selected to calculate the start-up parameters.

[0022] Optionally, when the selected calculation logic is the first calculation logic, the step of calculating the corresponding startup parameters according to the selected calculation logic specifically includes:

[0023] Get the actual battery level;

[0024] Determine the target battery charge corresponding to the actual vehicle speed;

[0025] The actual battery charge deviation is calculated using the actual battery charge and the target battery charge, and a pre-stored first startup mapping table is called; the first startup mapping table is used to represent the correspondence between the charge difference, power generation, and rotation speed.

[0026] The target power generation and target rotation speed are determined from the first startup mapping table based on the actual power deviation.

[0027] Optionally, in the first startup mapping table, when the power difference is negative and the deviation gradually increases, both the power generation and the rotation speed increase; when the power difference changes from negative to positive and the deviation gradually increases, the power generation is 0 and the rotation speed remains unchanged.

[0028] Optionally, when the selected calculation logic is the second calculation logic, the calculation of the corresponding startup parameters according to the selected calculation logic specifically includes:

[0029] Determine the vehicle speed calibration range based on the actual vehicle speed;

[0030] Based on the actual vehicle speed within the vehicle speed calibration range, the target power generation and the target rotational speed are determined from the pre-stored second startup mapping table; the second startup mapping table is used to represent the correspondence between the vehicle speed calibration range, power generation, and rotational speed.

[0031] Optionally, in the second startup mapping table, the vehicle speed calibration interval includes a first type of calibration interval and a second type of calibration interval; the first type of calibration interval and the second type of calibration interval are set alternately;

[0032] The first type of calibration interval includes N different levels of vehicle speed calibration intervals, where N≥2 and is a positive integer; wherein, within the same vehicle speed calibration interval, the engine's power generation and speed do not change with the change of vehicle speed value; the power generation and speed in the lower level vehicle speed calibration interval are less than the power generation and speed in the higher level vehicle speed calibration interval;

[0033] In the second type of calibration range, the power generation is the same as the power generation obtained previously, and the rotational speed is the same as the rotational speed obtained previously.

[0034] A second aspect of the present invention discloses a low-temperature starting system for a range-extended electric vehicle, the system comprising:

[0035] The acquisition module is used to acquire the temperature information of the range-extended electric vehicle in response to the start signal of the range-extended electric vehicle.

[0036] The judgment module is used to determine whether the range-extended electric vehicle is in a low-temperature state using the temperature information.

[0037] The calculation module is used to select the calculation logic for calculating engine starting parameters based on the actual speed of the range-extended electric vehicle when the range-extended electric vehicle is in a low-temperature state, and calculate the corresponding starting parameters according to the selected calculation logic.

[0038] The starting module is used to start the engine according to the calculated starting parameters, so as to indirectly increase the temperature of the power battery of the range-extended electric vehicle by increasing the circulating water temperature of the water circulation network; wherein the engine and the power battery share the water circulation network.

[0039] A third aspect of the present invention discloses a range-extended electric vehicle, including a memory, a vehicle controller, and a computer program stored in the memory and executable on the vehicle controller, wherein when the vehicle controller executes the computer program, the hybrid vehicle performs the method described in the first aspect.

[0040] Through one or more technical solutions of the present invention, the present invention has the following beneficial effects or advantages:

[0041] The technical solution disclosed in this invention, when identifying that a range-extended electric vehicle is driving at low water temperature, calculates the target power generation and target speed required to start the engine by selecting the corresponding calculation logic based on the actual vehicle speed, and starts the engine accordingly. This not only effectively increases the maximum power output of the vehicle, but also indirectly increases the temperature of the power battery of the range-extended electric vehicle by raising the circulating water temperature, thereby increasing the maximum discharge power of the battery and further increasing the maximum output power of the entire vehicle. This improves the acceleration performance and maximum steady-state power output capability of the range-extended electric vehicle under low temperature conditions, and increases the actual operating range of the vehicle.

[0042] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0043] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0044] In the attached diagram:

[0045] Figure 1 A schematic flowchart of a low-temperature start-up method for a range-extended electric vehicle according to an embodiment of the present invention is shown.

[0046] Figure 2 A schematic diagram of the start-stop strategy of the engine of a range-extended electric vehicle according to an embodiment of the present invention is shown.

[0047] Figure 3 A schematic diagram of a low-temperature starting system for a range-extended electric vehicle according to an embodiment of the present invention is shown. Detailed Implementation

[0048] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0049] Firstly, this specification provides a low-temperature starting method for a range-extended electric vehicle, primarily involving engine starting in low-temperature conditions to increase the temperature of the power battery. See also... Figure 1 This is a flowchart illustrating a low-temperature start-up method for a range-extended electric vehicle disclosed in an embodiment of the present invention. The method includes the following steps S101 to S104:

[0050] S101, in response to the start signal of the range-extended electric vehicle, acquires the temperature information of the range-extended electric vehicle.

[0051] The start signal for a range-extended electric vehicle (REEV) indicates the driver's intention to start the vehicle. Examples of start signals include key signals, voice signals, or control signals from third-party applications, but these are not limiting.

[0052] The temperature information for a range-extended electric vehicle (REEV) includes: the current actual coolant temperature and the coolant temperature at the moment the engine starts. The current actual coolant temperature refers to the temperature of the coolant in the water circulation network. This temperature changes depending on the actual driving conditions of the REEV. The water circulation network serves the electric motor and the battery, providing cooling for them. Since the electric motor and battery share a common water circulation network, the electric motor indirectly heats the battery by raising the circulating coolant temperature in the network after startup. The coolant temperature at the moment the engine starts refers to the coolant temperature of the engine at startup, representing the temperature environment the REEV was in before startup. For example, a coolant temperature of -10°C at engine startup indicates that the REEV is in a low-temperature environment. The current actual coolant temperature is not significantly different between the temperature before startup and the engine startup, but it changes constantly depending on the actual driving conditions.

[0053] In the process of acquiring temperature information of range-extended electric vehicles, the actual water temperature of the vehicle is collected by a temperature sensor installed in the water circulation network, and the water temperature at the moment of engine start is collected by a sensor installed in the engine.

[0054] S102, use the temperature information to determine whether the range-extended electric vehicle is in a low-temperature state. If yes, proceed to S103; otherwise, return to S101.

[0055] In the process of determining low coolant temperature, the maximum coolant temperature limit is determined by using the coolant temperature at the moment of engine startup. Different engine startup coolant temperatures correspond to different maximum coolant temperature limits. The maximum coolant temperature limit is one of the criteria for determining whether to start the engine in a range-extended electric vehicle. Table 1 shows the mapping relationship between the coolant temperature at engine startup and the maximum coolant temperature limit, but it does not constitute a restriction.

[0056] Table 1

[0057] Maximum water temperature limit (°C) 60 60 60 50 40 40 10 10 10 10 10

[0058] In Table 1, the lower the coolant temperature at engine start-up, the greater the likelihood of being in a low-temperature environment, and the higher the corresponding maximum coolant temperature limit. This means a higher probability that the circulating coolant temperature in the water circulation network will be below the maximum limit, necessitating more heating of the water circulation network. Conversely, a higher coolant temperature at engine start-up indicates a lower likelihood of being in a low-temperature environment, and a lower corresponding maximum coolant temperature limit. This means the water circulation network temperature is more likely to exceed the maximum limit, further reducing the probability of heating the circulating coolant temperature during engine start-up. Setting the coolant temperature at engine start-up and the maximum coolant temperature limit in a negatively correlated manner forms the basis for starting the engine in low-temperature conditions.

[0059] It is worth noting that the coolant temperature at engine start-up is not listed in Table 1. The corresponding maximum coolant temperature limit can be determined using proportional interpolation. For example, if the coolant temperature at engine start-up is -25℃, the corresponding maximum coolant temperature limit calculated using proportional interpolation is 60℃. In practical applications, the values ​​in Table 1 can be changed, but the underlying pattern of the data remains unchanged.

[0060] Furthermore, the engine coolant temperature threshold is used to detect the coolant temperature at the moment of engine startup, and the maximum coolant temperature limit is used to detect the actual coolant temperature of the vehicle at present. The engine coolant temperature threshold is calibrated based on empirical values. Both the engine coolant temperature threshold and the maximum coolant temperature limit serve as criteria for determining whether the range-extended electric vehicle should start its engine. If the coolant temperature at the moment of engine startup is lower than the engine coolant temperature threshold, and the actual coolant temperature of the vehicle at present is lower than the maximum coolant temperature limit, it is determined that the range-extended electric vehicle is in a low-temperature state, requiring engine startup to indirectly heat the power battery.

[0061] In the technical solution of the present invention, the combined detection of engine water temperature threshold and maximum water temperature limit at the start-up time and current water temperature of the range-extended electric vehicle can effectively identify the low-temperature state of the range-extended electric vehicle.

[0062] In one optional implementation, after the engine is started, the actual coolant temperature of the vehicle is detected in real time using the maximum coolant temperature limit; if the actual coolant temperature of the vehicle remains above the maximum coolant temperature limit for a set period of time, the engine is shut down. For example, if the actual coolant temperature of the vehicle remains above 10°C for more than 5 seconds, the engine is shut down.

[0063] like Figure 2 The diagram illustrates the start-stop strategy of a range-extended electric vehicle's engine. When the engine starts, if the coolant temperature is below the engine coolant temperature threshold and the vehicle's actual coolant temperature is below the maximum coolant temperature limit, the range-extended electric vehicle is in a low-temperature state, and the engine starts. After starting, if the vehicle's actual coolant temperature remains above the maximum coolant temperature limit for a set period of time, the engine stops. In other cases, the engine remains in the state determined at the previous moment.

[0064] S103, when the temperature information indicates that the range-extended electric vehicle is in a low-temperature state, select the calculation logic for calculating the engine start parameters according to the actual speed of the range-extended electric vehicle, and calculate the corresponding start parameters according to the selected calculation logic.

[0065] Specifically, the calculation logic includes a first calculation logic and a second calculation logic, with different calculation logics selected to start the engine at different vehicle speeds. When the actual vehicle speed equals a set threshold, the first calculation logic is selected to calculate the engine's starting parameters; when the actual vehicle speed exceeds the set threshold, the second calculation logic is selected to calculate the engine's starting parameters; the second calculation logic differs from the first calculation logic.

[0066] The engine's starting parameters include the target power generation and target speed for starting the engine. For example, a threshold is set to 0. When the actual vehicle speed is 0, that is, when the range-extended electric vehicle is stationary, the first calculation logic is selected to calculate the engine's target power generation and target speed; when the actual vehicle speed is greater than 0, that is, when the range-extended electric vehicle is running, the second calculation logic is selected to calculate the engine's target power generation and target speed.

[0067] By using vehicle speed as the criterion for selecting different calculation logics, the range-extended electric vehicle can execute different calculation logics to start the engine in a stationary state and a running state.

[0068] During the calculation of the corresponding start-up parameters according to the selected calculation logic, when the selected calculation logic is the first calculation logic, the range-extended electric vehicle's engine control enters the battery follow-up control state. The battery follow-up control state means that the engine's target power generation and target speed change in accordance with the actual circuit deviation value.

[0069] In the specific implementation process, the actual battery charge is acquired, and the target battery charge corresponding to the actual vehicle speed is determined. The target battery charge refers to the standard charge required at the actual vehicle speed, used as a condition to evaluate whether the actual battery charge is sufficient. Specifically, when the engine's target power generation and target speed are entered into the first calculation logic, the target battery charge is determined based on the mapping relationship between the actual vehicle speed and the target battery charge; the target battery charge can be calibrated. For example, when the vehicle speed is 0, the target battery charge is 20%.

[0070] The actual battery capacity deviation is calculated using the actual battery capacity and the target battery capacity, where the actual battery capacity deviation P SOC = Actual battery capacity SOC 实 -Target battery SOC 目 It is worth noting that the actual power deviation P SOC It can have negative, positive, and 0 values. A negative value represents the actual state of charge (SOC) of the battery. 实 Below target battery SOC 目 The larger the value, the greater the deviation; a positive value indicates the actual battery charge (SOC). 实 Above target battery SOC 目 The larger the value of P, the greater the deviation. SOC =0 indicates no deviation. Actual power deviation P SOC This indicates the difference between the actual battery level of a range-extended electric vehicle and the standard battery level required for the actual vehicle speed.

[0071] The pre-stored first startup mapping table is invoked. This first startup mapping table represents the correspondence between power difference, power generation, and rotational speed. See Table 2 for the first startup mapping table, but it does not impose limitations.

[0072] Table 2

[0073] Power generation capacity (kW) 10 10 7 5 3 1 0 0 0 0 0 Rotational speed (rpm) 2000 2000 1800 1800 1700 1600 1600 1600 1600 1600 1600

[0074] In the first startup mapping table, a negative battery charge difference indicates the actual battery SOC. 实 Below target battery SOC 目 And as the actual battery capacity SOC... 实 With the target battery capacity SOC 目 The greater the deviation between the actual battery capacity and the actual battery SOC, the lower the actual battery capacity. 实The greater the required power, the more the engine needs to be started to raise the temperature and charge the battery, thus the engine's power generation and speed will increase accordingly. Similarly, as the actual battery state of charge (SOC) increases... 实 With the target battery capacity SOC 目 The smaller the actual battery charge deviation, the lower the engine's power output and speed. When the charge difference changes from negative to positive, it indicates that the actual battery charge SOC (State of Charge) has reached a certain level. 实 Above target battery SOC 目 At this time, there is no need for the engine to charge the power battery, so the engine's power generation is fixed at 0, even as the actual battery charge SOC changes. 实 With the target battery capacity SOC 目 The greater the deviation from the actual battery charge, the higher the deviation gradually increases, as long as the actual battery charge SOC is maintained. 实 Above target battery SOC 目 If the engine speed remains constant at 0, the power generation will remain at 0. Since the engine still needs to raise the temperature of the power battery, the engine speed remains constant, and this constant value is not equal to 0.

[0075] Based on the first startup mapping table, the target power generation and target speed are determined from the table according to the actual power deviation. Specifically, the target power generation and target speed are obtained by looking up the table according to the actual power. It is worth noting that for values ​​whose actual power deviation does not appear in Table 2, the corresponding target power generation and target speed can be determined by proportional interpolation. For example, if the actual power deviation is -25℃, the corresponding target power generation is calculated to be 10kW and the target speed is 2000rpm by proportional interpolation. In practical applications, the values ​​in Table 2 can be changed, but the pattern of the data remains unchanged.

[0076] The above describes the implementation principle of the first calculation logic. By controlling the engine's target power generation and target speed to change in accordance with the actual circuit deviation, the temperature of the range-extended electric vehicle's power battery is indirectly increased by raising the circulating water temperature. This increases the battery's maximum discharge power while simultaneously enabling the engine to provide power output on demand, effectively increasing the vehicle's maximum power output. In this technical solution, when the power battery's power supply to the power system is insufficient, the generator directly provides power to the power system based on the target power generation and target speed, thereby increasing the vehicle's maximum output power. For example, if the user's power demand is 20kW, but the power battery can only provide 10kW, the engine can be started according to the calculated target power generation and target speed to directly provide 10kW of power to the power system, thereby increasing the vehicle's maximum power output to 20kW and meeting the user's power demand.

[0077] During the calculation of the corresponding start-up parameters according to the selected calculation logic, when the selected calculation logic is the second calculation logic, the range-extended electric vehicle's engine control enters a fixed-point power generation control state. The fixed-point power generation control state means that the engine's target power generation and target speed remain constant within each vehicle speed calibration range, without changing with vehicle speed. The engine's target power generation and target speed, within each vehicle speed calibration range, adapt to increasing vehicle speed.

[0078] In the specific implementation process, the vehicle speed calibration range is determined based on the actual vehicle speed; based on the actual vehicle speed within the calibration range, the target power generation and target speed are determined from a pre-stored second startup mapping table. The second startup mapping table represents the correspondence between the vehicle speed calibration range, power generation, and speed. In the second startup mapping table, the vehicle speed calibration range includes a first type of calibration range and a second type of calibration range; the first type of calibration range and the second type of calibration range are alternately set.

[0079] The first type of calibration interval includes N different levels of vehicle speed calibration intervals, where N ≥ 2 and is a positive integer; the higher the level, the larger the endpoint value of the calibration interval. Within the same vehicle speed calibration interval, the engine's power generation and speed do not change with the vehicle speed value; specifically, within the same vehicle speed calibration interval, different vehicle speed values ​​correspond to the same power generation and the same speed. That is, within the same vehicle speed calibration interval, even if the actual vehicle speed value changes arbitrarily within the interval, the engine's power generation and speed remain constant. For different levels of vehicle speed calibration intervals, the power generation and speed in lower-level vehicle speed calibration intervals are less than those in higher-level vehicle speed calibration intervals. In other words, the higher the level of the vehicle speed calibration interval, the greater the power generation and speed.

[0080] In the second type of calibration interval, the power generation and speed are based on the previously acquired values. Specifically, the second type of calibration interval is a self-return interval, set to avoid frequent switching of power generation and speed at each endpoint of the vehicle speed calibration interval, thus ensuring the stability of engine power output when vehicle speed changes. In the second type of calibration interval, the power generation and speed vary and depend on the previously acquired power generation and speed.

[0081] For example, the second startup mapping table is shown in Table 3, but this does not constitute a limitation.

[0082] Table 3

[0083] L1 <![CDATA[V≤V1 low ]]> P1 R1 S1 <![CDATA[V1 low <V≤V1 high ]]> Maintain the previous power generation capacity Maintain the previous speed L2 <![CDATA[V1 high <V≤V2 low ]]> P2 R2 S2 <![CDATA[V2 low <V≤V2 high ]]> Maintain the previous power generation capacity Maintain the previous speed L3 <![CDATA[V2 high <V≤V3 low ]]> P3 R3 S3 <![CDATA[V3 low <V≤V3 high ]]> Maintain the previous power generation capacity Maintain the previous speed L4 <![CDATA[V3 high <V≤V4 low ]]> P4 R4 S4 <![CDATA[V4 low <V≤V4 high ]]> Maintain the previous power generation capacity Maintain the previous speed L5 <![CDATA[V4 high <In]]> P5 R5

[0084] Where V represents the actual vehicle speed, V1 low V1 high V2low V2 high V3 low V3 high V4 low V4 high These are all endpoint values ​​of the vehicle speed calibration interval. The relationship between the magnitudes of each endpoint value is as follows: V1 low <V1 high <V2 low <V2 high <V3 low <V3 high <V4 low <V4 high The power generation ratios are: P1 < P2 < P3 < P4 < P5, and the rotational speed ratios are: R1 < R2 < R3 < R4 < R5. All of the above values ​​can be calibrated.

[0085] Referring to Table 3, there are five first-type calibration intervals: L1, L2, L3, L4, and L5; and four second-type calibration intervals: S1, S2, S3, and S4. The first-type and second-type intervals are alternated. The level of the five first-type calibration intervals gradually increases with the increase of the endpoint values. Therefore, the order of the five first-type calibration intervals is: L1 < L2 < L3 < L4 < L5. Within the same vehicle speed calibration interval, such as L1, regardless of changes in vehicle speed, the power generation remains constant at P1, and the engine speed remains constant at R1. In the second-type calibration interval, the power generation and engine speed vary and depend on the previously acquired power generation and engine speed. For example, if the actual vehicle speed was previously at V1... high <V≤V2 low Within this range, the target power generation P2 and target speed R2 are calculated. The actual vehicle speed jumps to V2 in the next measurement. low <V≤V2 high Within this range, the target power generation P2 and target speed R2 are maintained. If the actual vehicle speed was previously at V2... high <V≤V3 low Within this range, the target power generation P3 and target speed R3 are calculated. The actual vehicle speed jumps to V2 in the next measurement. low <V≤V2 high Within this range, the target power generation P3 and target speed R3 are maintained.

[0086] The above describes the implementation principle of the second calculation logic. By keeping the engine's target power generation and target speed constant within each vehicle speed calibration range, and by adaptively increasing the engine's target power generation and target speed as the vehicle speed increases within each calibration range, a stable output of the engine's target power generation and target speed is maintained. This, combined with increasing the circulating water temperature to raise the temperature of the range-extended electric vehicle's power battery and increase the battery's maximum discharge power, allows the engine to provide power output on demand, thereby effectively increasing the vehicle's maximum power output. The implementation principle for increasing the vehicle's maximum power output has already been described above and will not be repeated here.

[0087] It is worth noting that the target power generation corresponding to the second calculation logic is greater than the target power generation corresponding to the first calculation logic. The target rotational speed corresponding to the second calculation logic is greater than the target rotational speed corresponding to the first calculation logic.

[0088] In this technical solution, to adapt to different driving scenarios, vehicle speed is used as a dividing criterion to select different calculation logics to control the engine's target power generation and target speed. Specifically, the first calculation logic is applicable to the scenario of power battery heating when the range-extended electric vehicle is stationary. The second calculation logic is applicable to the scenario of power battery heating when the range-extended electric vehicle is in motion. Because the power level of the first calculation logic changes in real time with the actual power deviation value following the power generation status, it has defects such as noise and vibration, which will affect the range-extended electric vehicle when it is in motion. Therefore, when the vehicle speed increases, it switches to a fixed-point power generation state to control the engine to start, thereby improving the power of the range-extended electric vehicle and improving user comfort.

[0089] S104 starts the engine according to the target power generation and target speed, so as to indirectly increase the temperature of the power battery of the range-extended electric vehicle by increasing the circulating water temperature of the water circulation network.

[0090] The engine and the power battery share a common water circulation network.

[0091] After starting the engine, since the engine and the power battery share the same water circulation network, raising the water temperature in the network indirectly raises the power battery temperature. Furthermore, range-extended electric vehicles (REEVs) typically receive power directly from the power battery to the power system; however, insufficient battery power severely impacts the vehicle's range. Therefore, starting the engine according to the target power output and target speed, allowing the engine's power to be directly delivered to the power system, effectively increases the vehicle's maximum power output. For example, if the user's power demand is 20kW, but the power battery can only provide 10kW, starting the engine according to the calculated target power output and target speed directly provides 10kW to the power system, thereby increasing the vehicle's maximum power output to 20kW and meeting the user's power demand.

[0092] The solution of this invention, when it is identified that the range-extended electric vehicle is driving at low water temperature, calculates the target power generation and target speed required to start the engine by selecting the corresponding calculation logic based on the actual vehicle speed, and starts the engine accordingly. This not only effectively increases the maximum power output of the vehicle, but also increases the temperature of the power battery of the range-extended electric vehicle by raising the circulating water temperature, thereby increasing the maximum discharge power of the battery and further increasing the maximum output power of the entire vehicle. This improves the acceleration performance and maximum steady-state power output capability of the range-extended electric vehicle under low temperature conditions, and increases the actual operating range of the vehicle.

[0093] Secondly, based on the same inventive concept as the low-temperature starting method for range-extended electric vehicles provided in the first aspect of the embodiments described above, this specification also provides a low-temperature starting system for range-extended electric vehicles, see [link to documentation]. Figure 3 This is a schematic diagram of a low-temperature starting system for a range-extended electric vehicle provided in the embodiments of this specification. The system includes:

[0094] The acquisition module 301 is used to acquire the temperature information of the range-extended electric vehicle in response to the start signal of the range-extended electric vehicle.

[0095] The judgment module 302 is used to determine whether the range-extended electric vehicle is in a low-temperature state using the temperature information;

[0096] The calculation module 303 is used to select the calculation logic for calculating engine starting parameters according to the actual speed of the range-extended electric vehicle when the range-extended electric vehicle is in a low temperature state, and calculate the target power generation and target speed required to start the engine according to the selected calculation logic.

[0097] The starting module 304 is used to start the engine according to the calculated starting parameters, so as to indirectly increase the temperature of the power battery of the range-extended electric vehicle by increasing the circulating water temperature of the water circulation network; wherein the engine and the power battery share the water circulation network.

[0098] It should be noted that the specific operation methods of each module in the low-temperature starting system for range-extended electric vehicles provided in the embodiments of this specification have been described in detail in the method embodiments provided in the first aspect above. The specific implementation process can be referred to the method embodiments provided in the first aspect above, and will not be described in detail here.

[0099] Thirdly, based on the same inventive concept as the low-temperature start-up method for a range-extended electric vehicle provided in the first aspect of the embodiment, this specification also provides a range-extended electric vehicle, including a memory, a vehicle controller, and a computer program stored in the memory and executable on the vehicle controller. When the vehicle controller executes the computer program, it causes the hybrid vehicle to perform the method described in the first aspect.

[0100] It should be noted that the specific methods by which each module performs its operation in the range-extended electric vehicle provided in the embodiments of this specification have been described in detail in the method embodiments provided in the first aspect above. The specific implementation process can be referred to the method embodiments provided in the first aspect above, and will not be described in detail here.

[0101] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0102] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A low-temperature starting method for a range-extended electric vehicle, characterized in that, The method includes: In response to the start signal of the range-extended electric vehicle, the temperature information of the range-extended electric vehicle is acquired; the temperature information includes: the coolant temperature at the moment of engine start-up and the current actual coolant temperature of the vehicle. Determining whether the range-extended electric vehicle is in a low-temperature state using the temperature information specifically includes: determining a corresponding maximum coolant temperature limit using the coolant temperature at engine startup; detecting the coolant temperature at engine startup using an engine coolant temperature threshold, and detecting the actual coolant temperature of the current vehicle using the maximum coolant temperature limit; determining that the range-extended electric vehicle is in a low-temperature state when the coolant temperature at engine startup is lower than the engine coolant temperature threshold and the actual coolant temperature of the current vehicle is lower than the maximum coolant temperature limit; the coolant temperature at engine startup and the maximum coolant temperature limit are set to be negatively correlated. When the range-extended electric vehicle is in a low-temperature state, the calculation logic for calculating engine starting parameters is selected according to the actual speed of the range-extended electric vehicle, and the corresponding starting parameters are calculated according to the selected calculation logic. The engine is started according to the calculated starting parameters to indirectly increase the temperature of the power battery of the range-extended electric vehicle by increasing the circulating water temperature of the water circulation network; wherein the engine and the power battery share the water circulation network.

2. The method as described in claim 1, characterized in that, After starting the engine according to the calculated starting parameters, the method further includes: The actual water temperature of the current vehicle is detected in real time using the maximum water temperature limit. If the current actual water temperature of the vehicle remains above the maximum water temperature limit for a set period of time, the engine will be shut down.

3. The method as described in claim 1, characterized in that, The computational logic includes a first computational logic and a second computational logic; The calculation logic for selecting the engine starting parameters based on the actual speed of the range-extended electric vehicle specifically includes: When the actual vehicle speed equals a set threshold, the first calculation logic is selected to calculate the start-up parameters. When the actual vehicle speed is greater than the set threshold, the second calculation logic is selected to calculate the start-up parameters.

4. The method as described in claim 3, characterized in that, When the selected computation logic is the first computation logic, the step of calculating the corresponding startup parameters according to the selected computation logic specifically includes: Get the actual battery level; Determine the target battery charge corresponding to the actual vehicle speed; The actual battery charge deviation is calculated using the actual battery charge and the target battery charge, and a pre-stored first startup mapping table is called; the first startup mapping table is used to represent the correspondence between the charge difference, power generation, and rotation speed. The target power generation and target rotation speed are determined from the first startup mapping table based on the actual power deviation.

5. The method as described in claim 4, characterized in that, In the first startup mapping table, when the power difference is negative and the deviation gradually increases, both the power generation and the rotation speed increase; when the power difference changes from negative to positive and the deviation gradually increases, the power generation is 0 and the rotation speed remains unchanged.

6. The method as described in claim 3, characterized in that, When the selected computation logic is the second computation logic, the calculation of the corresponding startup parameters according to the selected computation logic specifically includes: Determine the vehicle speed calibration range based on the actual vehicle speed; Based on the actual vehicle speed within the vehicle speed calibration range, the target power generation and target speed are determined from the pre-stored second startup mapping table; the second startup mapping table is used to represent the correspondence between the vehicle speed calibration range, power generation, and speed.

7. The method as described in claim 6, characterized in that, In the second start-up mapping table, the vehicle speed calibration interval includes a first type of calibration interval and a second type of calibration interval; the first type of calibration interval and the second type of calibration interval are set alternately; The first type of calibration interval includes N different levels of vehicle speed calibration intervals, where N≥2 and is a positive integer; wherein, within the same vehicle speed calibration interval, the engine's power generation and speed do not change with the change of vehicle speed value; the power generation and speed in the lower level vehicle speed calibration interval are less than the power generation and speed in the higher level vehicle speed calibration interval; In the second type of calibration range, the power generation is the same as the power generation obtained previously, and the rotational speed is the same as the rotational speed obtained previously.

8. A low-temperature starting system for a range-extended electric vehicle, characterized in that, The system includes: The acquisition module is used to acquire the temperature information of the range-extended electric vehicle in response to the start signal of the range-extended electric vehicle; the temperature information includes: the coolant temperature at the moment of engine start and the current actual coolant temperature of the vehicle. The judgment module is used to determine whether the range-extended electric vehicle is in a low-temperature state using the temperature information. Specifically, it includes: determining a corresponding maximum coolant temperature limit using the coolant temperature at engine startup; detecting the coolant temperature at engine startup using an engine coolant temperature threshold, and detecting the actual coolant temperature of the current vehicle using the maximum coolant temperature limit; determining that the range-extended electric vehicle is in a low-temperature state when the coolant temperature at engine startup is lower than the engine coolant temperature threshold and the actual coolant temperature of the current vehicle is lower than the maximum coolant temperature limit; the coolant temperature at engine startup and the maximum coolant temperature limit are set to be negatively correlated. The calculation module is used to select the calculation logic for calculating engine starting parameters based on the actual speed of the range-extended electric vehicle when the range-extended electric vehicle is in a low-temperature state, and calculate the corresponding starting parameters according to the selected calculation logic. The starting module is used to start the engine according to the calculated starting parameters, so as to indirectly increase the temperature of the power battery of the range-extended electric vehicle by increasing the circulating water temperature of the water circulation network; wherein the engine and the power battery share the water circulation network.

9. A range-extended electric vehicle, comprising a memory, a vehicle controller, and a computer program stored in the memory and executable on the vehicle controller, characterized in that, When the vehicle controller executes the computer program, it causes the range-extended electric vehicle to perform the method as described in any one of claims 1-7.

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