A control method and control system of a range extended vehicle

Abstract

The application discloses a control method of a range-extender vehicle, comprising the following steps: acquiring the vehicle speed of the range-extender vehicle and the state of charge (SOC) of a power battery; if the range-extender vehicle is in a first running state, starting a range-extender, and controlling the range-extender to run at a highest efficiency point, wherein the first running state refers to that the vehicle speed is greater than or equal to a first preset vehicle speed, the state of charge (SOC) is less than or equal to a first threshold S1, and the range-extender vehicle is in a constant-speed cruise state; if the state of charge (SOC) is reduced to a target lower limit value of the state of charge (SOC) after the range-extender runs at the highest efficiency point, controlling the range-extender to run at a first constant-speed power point. The application further discloses a control system of the range-extender vehicle. According to the control method, the range-extender runs at the highest efficiency point in the first running state, fuel economy is improved, if the state of charge (SOC) demand is not met, the range-extender runs at the first constant-speed power point, power generation power is improved, the constant-speed cruise state is avoided to be exited, and the driving experience is affected, fuel economy and power generation power are considered.

Description

Technical Field

[0001] This application relates to the field of electric vehicle technology, and more specifically, to a control method and control system for a range-extended vehicle. Background Technology

[0002] A range extender typically consists of a small engine, a generator that integrates power generation and drive, an engine controller, and a generator controller. It can supply power to the vehicle's onboard battery or directly power the drive motor, thereby increasing the vehicle's driving range. In related technologies, the range extender is typically activated when the onboard battery's state of charge (SOC) is below a certain value during high-speed operation.

[0003] Currently, range extenders often employ a power-following strategy, where the range extender's operating point changes according to the vehicle's power demand. The range extender only starts and generates electricity when the vehicle's power demand is high (e.g., at high speeds on highways) and the battery's state of charge (SOC) is low. At this time, the engine operates in a high-speed, high-torque range, which can easily generate significant ground vibration and noise. Furthermore, according to the power-following strategy, the range extender operates in a low-efficiency region, making it difficult to balance fuel economy and power generation. This issue becomes particularly acute during high-speed cruise control, highlighting the critical challenge of achieving both fuel economy and power generation simultaneously. Therefore, resolving this balance issue is essential. Summary of the Invention

[0004] The purpose of this application is to provide a control method and control system for range-extended vehicles to solve the problem of difficulty in balancing fuel economy and power generation during high-speed cruise control.

[0005] To solve the above problems, this application adopts the following technical solution:

[0006] This application provides a control method for a range-extended vehicle, including:

[0007] Obtain the vehicle speed and the state of charge (SOC) of the power battery of the range-extended vehicle;

[0008] If the range-extended vehicle is in the first operating state, the range extender is started and controlled to operate at the highest efficiency point. The first operating state refers to: the vehicle speed is greater than or equal to the first preset vehicle speed, the state of charge (SOC) is less than or equal to the first threshold (S1), and the range-extended vehicle is in a constant speed cruise state.

[0009] If the State of Charge (SOC) decreases to the target lower limit after the range extender operates at its highest efficiency point, the range extender is controlled to operate at a first constant-speed power point to increase its power generation. The power generation at the first constant-speed power point is greater than the power generation at the highest efficiency point, and the power generation efficiency at the first constant-speed power point is less than the power generation efficiency at the highest efficiency point.

[0010] Furthermore, after the steps of starting the range extender and controlling it to operate at its highest efficiency point, the control method further includes:

[0011] If the State of Charge (SOC) increases to the target threshold, the range extender is shut down, and the range-extended vehicle enters EV mode.

[0012] Furthermore, after the step of controlling the range extender to operate at the first constant speed power point, the control method further includes:

[0013] If the State of Charge (SOC) increases to the target SOC upper limit, the range extender is controlled to switch from the first constant speed power point to the highest efficiency point.

[0014] Furthermore, after obtaining the vehicle speed and the state of charge (SOC) of the power battery of the range-extended vehicle, the control method further includes:

[0015] If the range-extended vehicle is in the second operating state, the range extender is started and controlled to operate at the first power point. The second operating state refers to the vehicle speed being less than the first preset vehicle speed and the state of charge (SOC) being less than or equal to the second threshold (S2). The second threshold (S2) is less than the first threshold (S1). The first power point and the highest efficiency point are the operating conditions of the range extender at different vehicle speeds.

[0016] Furthermore, after the step of starting the range extender and controlling the range extender to operate at the first power point, the control method further includes:

[0017] If the state of charge (SOC) of the range extender decreases to a third threshold (S3) after the range extender operates at the first power point, then the range extender is controlled to operate at the second power point, wherein the power generation at the second power point is greater than the power generation at the first power point.

[0018] Furthermore, after the step of controlling the range extender to operate at the second efficiency point, the control method further includes:

[0019] If the state of charge (SOC) decreases to the fourth threshold (S4) after the range extender operates at the second power point, then the range extender is controlled to operate at the maximum power point, wherein the power generation at the maximum power point is greater than the power generation at the second power point.

[0020] Furthermore, after the step of controlling the range extender to operate at its maximum power point, the control method further includes:

[0021] If the state of charge (SOC) increases to the second threshold S2 after the range extender operates at the maximum power point, then the range extender is controlled to switch from the maximum power point to the first power point.

[0022] Furthermore, after the step of starting the range extender and controlling the range extender to operate at the first power point, the control method further includes:

[0023] If the state of charge (SOC) increases to the target threshold after the range extender operates at the first power point, then the range extender is shut down.

[0024] This application also provides a control system for a range-extended vehicle, the control system being used to execute the above-described control method, the control system comprising a detection module and a control module, wherein...

[0025] The detection module is used to detect the vehicle speed, state of charge (SOC), and operating status of the range-extended vehicle.

[0026] The control module is used to control the range extender to operate at the highest efficiency point when the range-extended vehicle is in the first operating state, and to control the range extender to operate at the first constant speed power point after the range extender has operated at the highest efficiency point and the state of charge (SOC) has decreased to the target lower limit value. The first operating state refers to the following: the vehicle speed is greater than or equal to the first preset vehicle speed, the state of charge (SOC) is less than or equal to the first threshold S1, and the range-extended vehicle is in a constant speed cruise state.

[0027] Furthermore, the control module is also used for:

[0028] When the range-extended vehicle is in the second operating state, the range extender is started and controlled to operate at the first power point, wherein the second operating state refers to: the vehicle speed is less than the first preset vehicle speed and the state of charge (SOC) is less than or equal to the second threshold (S2).

[0029] The control method and control system for range-extended vehicles according to embodiments of this application include: the control method includes acquiring the vehicle speed and the state of charge (SOC) of the power battery of the range-extended vehicle; if the range-extended vehicle is in a first operating state, then the range extender is started and controlled to operate at its highest efficiency point; the first operating state refers to: the vehicle speed being greater than or equal to a first preset vehicle speed, the SOC being less than or equal to a first threshold S1, and the range-extended vehicle being in a constant speed cruise state; if the SOC decreases to a target lower limit after the range extender operates at its highest efficiency point, then the range extender is controlled to operate at a first constant speed power point. In the control method of this application, when the range-extended vehicle is in the first operating state, the range extender operates at the highest efficiency point to improve fuel economy. If the state of charge (SOC) decreases to the lower limit of the target SOC after the range extender operates at the highest efficiency point, making it difficult to meet the SOC requirement, the range extender switches from the highest efficiency point to the first constant speed power point to increase power generation to meet the SOC requirement. This reduces the risk of exiting the cruise control state due to insufficient SOC, which would affect the driving experience. By first judging the operating state of the range-extended vehicle, the range extender can select between the highest efficiency point and the first constant speed power point during high-speed cruise control, thus balancing fuel economy and power generation. Attached Figure Description

[0030] Figure 1 A flowchart illustrating the first control method for a range-extended vehicle provided in this application embodiment;

[0031] Figure 2 A flowchart illustrating a second control method for a range-extended vehicle provided in an embodiment of this application;

[0032] Figure 3 A flowchart illustrating the third control method for a range-extended vehicle provided in this application embodiment;

[0033] Figure 4 A flowchart illustrating the fourth control method for a range-extended vehicle provided in this application embodiment;

[0034] Figure 5 A flowchart illustrating the fifth control method for a range-extended vehicle provided in this application embodiment;

[0035] Figure 6 A system block diagram of a control system for a range-extended vehicle provided in an embodiment of this application;

[0036] Figure 7 An optimization strategy diagram is provided in the control method of a range-extended vehicle according to an embodiment of this application, wherein the operating points of the range extender at different speeds are displayed.

[0037] Figure 8A control strategy diagram for a control method of a range-extended vehicle provided in an embodiment of this application;

[0038] Figure 9 A control strategy diagram for another control method for a range-extended vehicle provided in this application embodiment; and

[0039] Figure 10 This is the logic control diagram for a range extender in the prior art. Detailed Implementation

[0040] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0041] It should be noted that, unless otherwise specified, the embodiments and technical features in the embodiments of this application can be combined with each other, and the detailed descriptions in the specific implementation should be understood as explanations of the purpose of this application and should not be regarded as undue limitations on this application.

[0042] It should be understood that the orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings. These orientation terms are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this application.

[0043] In the description of this application, the terms "first / second" are used merely to distinguish similar objects and do not represent a specific order of objects. It is understood that "first / second" may be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0044] Hybrid systems are currently the most promising vehicle type on the market, with range-extended electric vehicles (REEVs) gaining increasing popularity. Compared to traditional vehicles, REEVs significantly reduce fuel consumption and emissions by matching the engine's high-efficiency operating point, meeting China VI / China VII emission standards. Compared to HEV (Hybrid Electric Vehicle) and PHEV (Plug-in Hybrid Electric Vehicle) models, range extenders minimize range anxiety, achieving the range of a traditional vehicle while providing the driving experience of a pure electric vehicle.

[0045] In a hybrid architecture, the range extender is only used to provide electric power; the engine does not participate in the direct drive of the vehicle. The range extender is completely decoupled from the overall vehicle operation, and its operating point is not directly related to vehicle speed. Therefore, from the perspective of overall vehicle performance, maximizing the performance potential of the range extender, rationally matching its operating point, and optimizing control strategies are extremely important.

[0046] However, as Figure 10 As shown, based on the operating efficiency of the range extender, there are two existing range extender control strategies: 1—Fixed-point strategy (multi-point operating conditions), which selects multiple range extender power matching points based on the vehicle's common operating power requirements; 2—Power following strategy, which adjusts the range extender matching point according to the vehicle's power requirements based on the optimal efficiency point under different range extender power levels. Compared to traditional vehicles, hybrid vehicles are heavier, especially PHEVs, which often exhibit a "small horse pulling a heavy load" phenomenon when the battery is depleted. Due to high power requirements, the vehicle experiences abnormally high fuel consumption at high speeds and a poor user experience when the battery is depleted. Simultaneously, the range extender operates at high speeds in depleted mode, resulting in insufficient NVH (noise, vibration, and harshness). For example, if the vehicle requires high power at high speeds, according to the existing strategy, the range extender matching point operates under high-speed, high-load conditions, which is in the range extender's low-efficiency region (see reference). Figure 10 At medium to high speed operating conditions (matching point), fuel consumption is very high, resulting in poor fuel economy. Especially when the vehicle is at high speed and cruise control, insufficient power generation will further reduce the State of Charge (SOC), affecting driving range. Conversely, high power generation leads to poor fuel economy and lower efficiency of the range extender. Therefore, at high speeds and cruise control, to meet the demands of these conditions, a balance needs to be struck between the SOC, the range extender's power generation, and its efficiency. For example, if an appropriate power generation is chosen to ensure fuel economy, the range extender's power generation decreases. Furthermore, because the vehicle is in a high-power-demand phase while the battery's SOC is already low, the battery still needs to provide some power to the drive motor to maintain power demand, resulting in a shorter driving range and failing to meet range requirements.

[0047] In view of this, such as Figure 1 As shown in the figure, this application provides a control method for a range-extended vehicle, including:

[0048] S101. Obtain the vehicle speed and the state of charge (SOC) of the power battery of the range-extended vehicle.

[0049] S201. If the range-extended vehicle is in the first operating state, the range extender is started and controlled to operate at the highest efficiency point. The first operating state refers to: the vehicle speed is greater than the first preset vehicle speed, the state of charge (SOC) is less than or equal to the first threshold S1, and the range-extended vehicle is in a constant speed cruise state.

[0050] S301. If the state of charge (SOC) of the range extender decreases to the target lower limit after operating at the highest efficiency point, the range extender is controlled to operate at the first constant speed power point to increase the power generation of the range extender. The power generation at the first constant speed power point is greater than the power generation at the highest efficiency point, and the power generation efficiency at the first constant speed power point is less than the power generation efficiency at the highest efficiency point.

[0051] Specifically, after the range-extended vehicle is powered on and running, the vehicle speed and the state of charge (SOC) of the power battery are acquired. For example, the controller reads the vehicle speed and SOC data, and determines the operating status of the range extender based on different vehicle speeds and different SOC values. When the vehicle speed is greater than a first preset speed, the SOC is less than or equal to a first threshold S1, and the range-extended vehicle is in cruise control mode, it is determined that the range-extended vehicle is in the first operating state. At this time, the range extender is started and controlled to operate at its highest efficiency point.

[0052] For example, the range extender has high-speed fixed point 3, high-speed fixed point 4, and high-speed fixed point 5. Among them, high-speed fixed point 3 is the commonly used high-speed operating point, which represents the highest efficiency point of the range extender and the optimal fuel economy (see [link]). Figure 7 When the vehicle speed is greater than the first preset speed, the range-extended vehicle is in a high-speed operating state. Further judgment is made on the State of Charge (SOC) and the current operating state of the range-extended vehicle. If the State of Charge (SOC) is less than or equal to the first threshold S1 and the range-extended vehicle is in a constant speed cruise state, it is determined that the range-extended vehicle is in the first operating state. At this time, the range extender is started and controlled to operate at the high-speed fixed point 3.

[0053] It should be noted that the first threshold S1 is higher than the State of Charge (SOC) threshold for normal range extender startup. For example, the first threshold S1 is 40%, while the normal SOC threshold for range extender startup is 30%. When the range-extended vehicle is in its first operating state, the range extender starts when the SOC is less than or equal to 40% and operates at the high-speed fixed point 3 (maximum efficiency point). When the range-extended vehicle is in normal operation, the range extender only starts when the SOC is less than or equal to 30%. Because the range-extended vehicle has a higher power demand in its first operating state, a larger threshold (first threshold S1) is used compared to the normal startup threshold, allowing the range extender to start earlier and operate at the high-speed fixed point 3 (maximum efficiency point) to achieve optimal operating efficiency and improve fuel economy. It should be understood that normal range extender startup indicates a non-high-speed constant-speed cruise state, such as when the range-extended vehicle is operating at low speed. In this case, it can be considered a normal situation, and the range extender only starts when the SOC is less than or equal to 30%.

[0054] Once the range extender starts, at its highest efficiency point (reference) Figure 8 After the medium-to-high speed fixed-point operation (3), since the range-extended vehicle is in its first operating state, if the State of Charge (SOC) decreases to the lower limit of the target SOC, the range extender will be controlled to operate at the first constant speed power point. For example, if the lower limit of the target SOC is 35%, when the range extender starts, it will operate at its highest efficiency point (refer to...). Figure 8After the medium-speed fixed-point 3) operation, the state of charge (SOC) decreases from 40% to 35%. This indicates that the power generation of the range-extended vehicle at the highest efficiency point is insufficient to meet the current power consumption demand of the first operating state. The range-extended vehicle needs to increase its power generation, and the controller controls the range extender to switch from the highest efficiency point to the first fixed-speed power point.

[0055] It should be understood that if the power generation efficiency at the first constant-speed power point is still insufficient to meet the power consumption demand—that is, if the state of charge (SOC) of the range extender is still decreasing when operating at the first constant-speed power point—then the range extender will be controlled to operate at a second constant-speed power point with higher power generation at high speeds. For example, such as... Figure 7 and Figure 8 As shown, the first constant-speed power point is high-speed constant point 4, and the second constant-speed power point is high-speed constant point 5. After the range extender starts and operates at the highest efficiency point (high-speed constant point 3), the state of charge (SOC) decreases from 40% to 35%. This indicates that the power generation of the range-extended vehicle operating at the highest efficiency point is insufficient to meet the current power consumption demand of the first operating state. The range-extended vehicle needs to increase its power generation, and the controller controls the range extender to switch from the highest efficiency point to the first constant-speed power point. If, under the first constant-speed power point, the SOC decreases from 35% to 32%, this indicates that the power generation of the range-extended vehicle operating at the first constant-speed power point is still insufficient to meet the current power consumption demand. The range extender needs to further increase its power generation, and the range extender switches from the first constant-speed power point to the second constant-speed power point. Extending this strategy, if the second constant-speed power point also cannot meet the power consumption demand of constant-speed cruise at high speed, it can further jump to the next constant-speed power point, or even to the maximum power point at high speed.

[0056] It should be understood that range-extended vehicles can perform cruise control at different speeds. Especially at high speeds, if the current range extender's power generation cannot meet the current power consumption demand, the vehicle may easily disengage from high-speed cruise control, thus affecting the driving experience. For example, the State of Charge (SOC) requirements for cruise control at 90 km / h and 120 km / h are different. At high speed point 3, the SOC can meet the needs of cruise control at 90 km / h (increasing from 40%), but at high speed point 3, it may be difficult to meet the needs of cruise control at 120 km / h (SOC decreasing from 40%). In this case, the range extender will switch to high speed point 4 to obtain greater power generation.

[0057] In the control method of this application, when the range-extended vehicle is in the first operating state, the range extender operates at the highest efficiency point to improve fuel economy. If the state of charge (SOC) decreases to the lower limit of the target SOC after the range extender operates at the highest efficiency point, making it difficult to meet the SOC requirement, the range extender switches from the highest efficiency point to the first constant speed power point to increase power generation to meet the SOC requirement. This reduces the risk of exiting the cruise control state due to insufficient SOC, which would affect the driving experience. By first judging the operating state of the range-extended vehicle, the range extender can select between the highest efficiency point and the first constant speed power point during high-speed cruise control, thus balancing fuel economy and power generation.

[0058] In one embodiment, such as Figure 2 As shown, after steps S201, starting the range extender and controlling it to operate at its highest efficiency point, the control method further includes:

[0059] S202. If the State of Charge (SOC) increases to the target threshold, the range extender will be shut down and the range-extended vehicle will enter EV mode.

[0060] Specifically, after the range extender starts and operates at its highest efficiency point, if the State of Charge (SOC) begins to increase and reaches the target threshold over time, the range extender will be shut down, and the range-extended vehicle will enter EV mode. For example, if the target threshold is 90%, after the range extender starts and operates at its highest efficiency point (high-speed fixed point 3), if the SOC begins to increase and reaches 90% over time, the range extender will be shut down, and the range-extended vehicle will enter EV mode.

[0061] It should be understood that when the range extender starts and operates at its highest efficiency point, if the state of charge (SOC) begins to increase, it indicates that the power generation of the range-extended vehicle operating at its highest efficiency point can meet the current power consumption requirements of the first operating state. The range-extended vehicle does not need to increase its power generation capacity; it can achieve the best working efficiency and the best fuel economy by operating at its highest efficiency point.

[0062] In one embodiment, such as Figure 2 and Figure 8 As shown, after step S301, controlling the range extender to operate at the first constant speed power point, the control method further includes:

[0063] S302. If the State of Charge (SOC) increases to the target SOC upper limit, the range extender is controlled to switch from the first constant speed power point to the highest efficiency point.

[0064] Specifically, after the range extender starts and operates at the first constant speed power point, if the state of charge (SOC) begins to increase and reaches the target SOC upper limit over time, the range extender is controlled to switch from the first constant speed power point to the highest efficiency point. For example, if the target SOC upper limit is 60%, after the range extender starts and operates at the first constant speed power point (high-speed fixed point 4), if the SOC begins to increase and reaches 60% over time, the range extender is controlled to shut down and switch from the first constant speed power point to the highest efficiency point (high-speed fixed point 3) (see [link]). Figure 8 ).

[0065] It should be understood that after the range extender starts and operates at the first constant speed power point, if the state of charge (SOC) begins to increase, it indicates that the power generation of the range extender operating at the first constant speed power point can meet the current power consumption demand of the first operating state. The range extender does not need to increase its power generation again; operating at the first constant speed power point can meet the current SOC power consumption demand. If the SOC increases to the target SOC upper limit, the range extender is controlled to switch from the first constant speed power point to the highest efficiency point. By switching the operating point of the range extender in the above "reciprocating" manner, the optimal working efficiency, fuel economy, and cruise driving experience at the current vehicle speed can be effectively balanced.

[0066] In one embodiment, such as Figure 3 As shown, after steps S101, which involve obtaining the vehicle speed of the range-extended vehicle and the state of charge (SOC) of the power battery, the control method further includes:

[0067] S102. If the range-extended vehicle is in the second operating state, the range extender is started and controlled to operate at the first power point. The second operating state refers to the vehicle speed being less than the first preset vehicle speed and the state of charge (SOC) being less than or equal to the second threshold S2. The second threshold S2 is less than the first threshold S1. The first power point and the highest efficiency point are the operating conditions of the range extender at different vehicle speeds.

[0068] Specifically, if the vehicle speed is less than a first preset speed and the state of charge (SOC) is less than or equal to a second threshold (S2), the range-extended vehicle is determined to be in a second operating state. At this time, the range extender is activated and controlled to operate at the first power point. For example, if... Figure 9 As shown, the second threshold S2 is a percentage A (30%). When the vehicle speed is less than the first preset vehicle speed and the state of charge (SOC) is less than or equal to A, the range-extended vehicle is determined to be in the second operating state. The range extender is then activated and controlled to operate at the first power point. Specifically, point 1 (first power point) is the highest efficiency operating condition of the range extender at lower vehicle speeds, and the highest efficiency point (high-speed point 3) is the highest efficiency operating point of the range extender at higher vehicle speeds.

[0069] It should be understood that since the vehicle speed is lower than the first preset speed, it indicates that the current vehicle speed is low and not at high speed. Its power consumption is far lower than the demand in the first operating state. Activating the range extender and controlling it to operate at the first power point can meet the power consumption demand at the current vehicle speed.

[0070] In one embodiment, such as Figure 3 As shown, after steps S102, starting the range extender and controlling it to operate at the first power point, the control method further includes:

[0071] S103. If the state of charge (SOC) of the range extender decreases to the third threshold S3 after operating at the first power point, then the range extender is controlled to operate at the second power point, wherein the power generation at the second power point is greater than the power generation at the first power point.

[0072] Specifically, when the vehicle speed is less than the first preset speed, the range extender is activated, and the range extender is controlled to operate at the first power point, if the state of charge (SOC) decreases, it indicates that the range extender's power generation is insufficient to meet the current power demand when operating at the first power point, and the power generation needs to be increased. At this time, the SOC decreases to the third threshold S3, and the range extender is controlled to switch from the first power point to the second power point, thereby increasing the power generation. For example, the third threshold is Ab, such as... Figure 9 As shown, when the vehicle speed is less than the first preset speed and the state of charge (SOC) is less than or equal to A, the range extender is started and controlled to run at fixed point 1. If the SOC decreases after the range extender runs at fixed point 1, and the SOC decreases to Ab, the range extender switches from fixed point 1 to fixed point 2.

[0073] It should be noted that the power generation at the second power point is greater than that at the first power point, but the fuel economy and operating efficiency at the second power point are both lower than those at the first power point.

[0074] In one embodiment, such as Figure 4 As shown, after step S103, which controls the range extender to operate at the second efficiency point, the control method further includes:

[0075] S104. If the state of charge (SOC) of the range extender decreases to the fourth threshold (S4) after the range extender operates at the second power point, then the range extender is controlled to operate at the maximum power point, where the power generation at the maximum power point is greater than the power generation at the second power point.

[0076] Specifically, when the vehicle speed is less than the first preset speed, the range-extended vehicle is in the second operating state. After the range extender operates at the second power point, the state of charge (SOC) decreases, indicating that the power generation of the range extender is insufficient to meet the current power consumption demand when operating at the second power point, and the power generation needs to be further increased. At this time, the SOC decreases to the fourth threshold S4, controlling the range extender to switch from the second power point to the maximum power point operation, thereby increasing the power generation. For example, the fourth threshold is Abcd, such as... Figure 9 As shown, when the vehicle speed is less than the first preset speed and the state of charge (SOC) is less than or equal to A, the range extender is started and controlled to operate at fixed point 1. If the SOC decreases after the range extender operates at fixed point 1, and the SOC decreases to Ab, the range extender switches from fixed point 1 to fixed point 2. If the power consumption demand at the current vehicle speed is still not met under fixed point 2 operation, the range extender is controlled to operate at the maximum power point to maximize power generation and prevent the vehicle from losing power.

[0077] It should be noted that the above description only uses the second power point, the first power point, and the maximum power point. In other practical situations, a third power point, a fourth power point, a fifth power point, etc., can be added, up to the maximum power point. The number of power points from the first power point to the maximum power point can be determined according to the actual situation. In this application embodiment, only the first power point, the second power point, and the maximum power point are used as examples and should not be construed as limiting this application. For example, as Figure 9 As shown, when the vehicle speed is less than the first preset vehicle speed and the state of charge (SOC) is less than or equal to A, the range extender is controlled by fixed point 1, fixed point 2, fixed point 3 and the maximum power point.

[0078] In one embodiment, such as Figure 4 As shown, after step S104, which controls the range extender to operate at its maximum power point, the control method further includes:

[0079] S105. If the state of charge (SOC) of the range extender increases to the second threshold S2 after it has been operating at the maximum power point, then the range extender is controlled to switch from operating at the maximum power point to operating at the first power point.

[0080] Specifically, when the vehicle speed is less than the first preset speed, the range-extended vehicle is in the second operating state. After the range extender operates at its maximum power point, the state of charge (SOC) increases. When the SOC increases to the second threshold S2, the range extender is controlled to switch from operating at the maximum power point to operating at the first power point. At this time, it indicates that after operating at the maximum power point for a period of time, the range extender can meet the vehicle's operating requirements, and the accumulated electricity during this period meets the corresponding threshold. After switching to the fixed point 1, the fuel economy of the vehicle at low speeds is also at its optimal state, improving the working efficiency of the range extender.

[0081] It should be noted that the above description is only illustrative of the case where the State of Charge (SOC) increases after operation at the maximum power point, and should not be construed as a limitation of this application. Given fixed points 1, 2, 3, and the maximum power point, if the range extender operates at any of these points and the SOC increases to a certain threshold, the range extender will sequentially jump to the next higher level until it returns to fixed point 1. For example, if the range extender operates at fixed point 3 and the SOC increases to a value greater than Ab-c+k2, the range extender will switch from fixed point 3 to fixed point 2. Correspondingly, after fixed point 2 meets the corresponding conditions, it will jump back to fixed point 1.

[0082] In one embodiment, such as Figure 5 As shown, after steps S102, starting the range extender and controlling it to operate at the first power point, the control method further includes:

[0083] S112. If the state of charge (SOC) of the range extender increases to the target threshold after the range extender operates at the first power point, then the range extender shall be shut down.

[0084] Specifically, when the vehicle speed is less than the first preset speed, the range-extended vehicle is in the second operating state, and the range extender is controlled to operate at the first power point. After the range extender operates at the first power point for a certain period of time, the state of charge (SOC) increases and reaches the target threshold, then the range extender is turned off, and the range-extended vehicle enters EV mode.

[0085] For example, at a vehicle speed of 20 km / h and a State of Charge (SOC) of less than or equal to 30%, the range extender starts and operates at fixed point 1. When the SOC increases to 90%, the range extender shuts off. Conversely, if the vehicle speed is 50 km / h and the SOC is less than or equal to 30%, the range extender starts and operates at fixed point 1. After operating at fixed point 1, if the SOC decreases and becomes less than or equal to Ab, the range extender switches from fixed point 1 to fixed point 2 to increase power generation.

[0086] like Figure 6 As shown in the embodiment of this application, a control system 100 for a range-extended vehicle is also provided. The control system is used to execute the control method described above. The control system 100 includes a detection module 110 and a control module 120. The detection module 110 is used to detect the vehicle speed, state of charge (SOC), and operating state of the range-extended vehicle. The control module 120 is used to control the range extender to operate at the highest efficiency point when the range-extended vehicle is in a first operating state, and to control the range extender to operate at a first constant speed power point when the state of charge (SOC) decreases to the target lower limit value after the range extender has operated at the highest efficiency point. The first operating state refers to: the vehicle speed is greater than or equal to a first preset vehicle speed, the state of charge (SOC) is less than or equal to a first threshold S1, and the range-extended vehicle is in a constant speed cruise state.

[0087] Specifically, the detection module 110 detects the vehicle speed and state of charge (SOC) of the range-extended vehicle. For example, the detection module 110 is equipped with multiple sensors to acquire the vehicle speed and SOC. Simultaneously, the detection module 110 can also detect the current operating status of the vehicle, such as whether the vehicle is in EV mode or cruise control mode. After the detection module 110 detects the vehicle speed, if it is greater than or equal to a first preset speed, the SOC is less than or equal to a first threshold S1, and the range-extended vehicle is in cruise control mode, then it is determined that the current range-extended vehicle is in the first operating state, and the control module 120 controls the range extender to operate at its highest efficiency point.

[0088] In particular, such as Figure 9 As shown, the detection module 110 detects that the vehicle speed is greater than or equal to the first preset speed, indicating that the vehicle is in a high-speed condition. If the SOC is less than or equal to 40%, and the detection module 110 detects that the vehicle is in cruise control mode, the control module 120 controls the range extender to operate at the highest efficiency point (high-speed fixed point 3).

[0089] By using the detection module 110 and the control module 120, when the range-extended vehicle is in its first operating state, the range extender operates at its highest efficiency point to improve fuel economy. If, after the range extender operates at its highest efficiency point, the State of Charge (SOC) decreases to the lower limit of the target SOC, making it difficult to meet the SOC requirement, the range extender switches from the highest efficiency point to the first constant speed power point to increase power generation and meet the SOC requirement. This reduces the risk of exiting cruise control due to insufficient SOC, which would affect the driving experience. By first judging the operating state of the range-extended vehicle, the range extender can select between the highest efficiency point and the first constant speed power point during high-speed cruise control, thus balancing fuel economy and power generation.

[0090] In one embodiment, the control module 120 is further configured to: start the range extender and control the range extender to operate at a first power point when the range-extended vehicle is in a second operating state, wherein the second operating state refers to: the vehicle speed is less than a first preset vehicle speed and the state of charge (SOC) is less than or equal to a second threshold (S2).

[0091] Specifically, after the detection module 110 detects the vehicle speed and state of charge (SOC) of the range-extended vehicle, if the vehicle speed is less than the first preset vehicle speed and the SOC is less than or equal to the second threshold S2, then when it is determined that the current range-extended vehicle is in the second operating state, the control module 120 controls the range extender to operate at the first power point.

[0092] For example, such as Figure 9As shown, the detection module 110 detects that the vehicle speed is less than the first preset speed, indicating that the vehicle is in a medium or low speed condition. If the SOC is less than or equal to 30%, and the detection module 110 detects that the vehicle is in a non-cruise mode, the control module 120 controls the range extender to operate at the first power point (fixed point 1).

[0093] To better understand the control method for range-extended vehicles in the embodiments of this application, the following is combined with... Figure 8 and Figure 9 The control logic of range-extended vehicles is explained.

[0094] When the range-extended vehicle is at a low speed (below the first preset speed), the range extender is controlled based on the state of charge (SOC) of the power battery. When the SOC is low (below the second threshold S2), the range extender is activated.

[0095] When the range-extended vehicle is in high-speed cruise control mode, the control logic of the range extender is as follows: When the state of charge (SOC) drops to a low level, and the vehicle speed is checked to see if the target high speed has been reached (vehicle speed greater than or equal to a first preset speed), the range extender enters a high-speed fixed-point mode. For example, the high-speed fixed-point mode includes high-speed fixed point 3, high-speed fixed point 4, and high-speed fixed point 5. Among them, high-speed fixed point 3 is the commonly used high-speed operating point, which represents the highest efficiency point of the range extender and the optimal fuel economy. When the range-extended vehicle is in high-speed cruise control mode and the SOC is less than or equal to the first threshold S1, the range extender starts and is controlled to operate at high-speed fixed point 3 (the highest efficiency point). It should be noted that the first threshold S1 is higher than the second threshold S2 for the state of charge (SOC) at low speeds when the range extender starts. For example, if the first threshold S1 is 40% and the second threshold S2 is 30%, when the range-extended vehicle is in high-speed cruise control mode, the SOC is less than or equal to 40%, the range extender starts, and operates at the high-speed fixed point 3 (the highest efficiency point). When the range-extended vehicle is in low-speed mode, the SOC is less than or equal to 30%, and the range extender only starts then. Because the range-extended vehicle has a higher power demand in high-speed cruise control mode, a larger threshold (first threshold S1) is used compared to the starting threshold in low-speed mode, allowing the range extender to start earlier and operate at the high-speed fixed point 3 (the highest efficiency point), achieving optimal operating efficiency and improving fuel economy.

[0096] When the range extender starts and operates at high-speed station 3 (maximum efficiency point), since the range-extended vehicle is in high-speed cruise mode, if the State of Charge (SOC) continues to decrease, the range extender will be controlled to enter a high-power point (high-speed station 4 / 5). After the battery level rises to the target SOC, it enters high-speed station 3, switching between the optimal efficiency point 3 and high-power points 4 / 5 to ensure the high-speed fuel efficiency of the range-extended hybrid vehicle. It should be noted that high-speed station 4 / 5 represents high-speed station 4 or high-speed station 5. High-speed station 5 has a higher power generation capacity than high-speed station 4, but its operating efficiency and fuel economy are relatively lower than high-speed station 4. For example, if the range extender enters high-speed station 4 but still cannot meet the requirements of high-speed cruise mode and the current SOC, and the SOC is still decreasing, the range extender will be controlled to enter station 5.

[0097] Once the range extender enters high-speed cruise control point 4, and the State of Charge (SOC) rises to the target SOC upper limit, the range extender switches from high-speed cruise control point 4 to high-speed cruise control point 3 (the highest efficiency point). Depending on the specific SOC situation, it switches between high-speed cruise control point 3 and high-power points 4 / 5, thus balancing the fuel economy, driving experience, and power generation of the range-extended vehicle under high-speed cruise control conditions. This avoids the vehicle being forced to exit high-speed cruise control due to insufficient SOC, which would affect the driving experience.

[0098] For example, by identifying the vehicle's driving mode, the range extender is activated based on the battery's state of charge (SOC) and vehicle speed. The operating point of the range extender is determined. When the SOC is ≤40% and the vehicle is in high-speed cruise control, the range extender starts early, entering its highest efficiency point (high-speed station 3). While operating at high-speed station 3, if the SOC continues to decrease and reaches the target lower limit, the range extender enters high-speed station 4 or 5 (based on vehicle speed), putting it in a high-power generation state to quickly replenish the depleted battery. When operating at high-speed station 4 or 5, if the SOC continues to increase and reaches the target upper limit, it enters high-speed station 3. By switching the range extender between high-speed station 3 and high-speed station 4 / 5, the high-speed fuel economy of the range-extended vehicle is ensured. When the State of Charge (SOC) increases to the target threshold at high speed constant speed cruise 3, the range extender shuts off. At this point, the power battery's charge is sufficient to meet the needs of high-speed constant speed cruise, and the range extender does not need to operate.

[0099] like Figure 9As shown, when the vehicle speed is less than the first preset speed and the state of charge (SOC) is less than or equal to the second threshold S2, and the second threshold S2 is less than the first threshold S1, the range extender is activated and controlled to operate at the first power point. The first power point is the operating condition of the range extender at low speed (vehicle speed less than the first preset speed), and the highest efficiency point is the operating condition of the range extender at high speed (vehicle speed greater than or equal to the first preset speed). For example, the second threshold S2 is 30% (reference). Figure 9 When the vehicle speed is less than the first preset speed and the state of charge (SOC) is less than 30%, the range extender is started and controlled to run at fixed point 1.

[0100] If the State of Charge (SOC) continues to decrease after the range extender has been operating at fixed point 1 (see reference). Figure 9 When the State of Charge (SOC) is less than or equal to Ab, the range extender switches from point 1 to point 2 to meet the SOC requirement. Point 2 has a larger power generation capacity than point 1, but its operating efficiency and fuel economy are lower.

[0101] If the State of Charge (SOC) continues to decrease after the range extender has been operating at fixed point 2 (see reference). Figure 9 (When SOC ≤ Abc), the range extender switches from fixed point 2 to fixed point 3 to meet the SOC requirement. Fixed point 3 has a larger power generation capacity than fixed point 2, but fixed point 3 has lower operating efficiency and fuel economy than fixed point 2.

[0102] If the State of Charge (SOC) continues to decrease after the range extender has been running at point 3 (see reference). Figure 9 When the SOC is less than or equal to Abcd, the range extender switches from point 3 to maximum power point operation, putting the range extender in maximum power generation state to increase the SOC as quickly as possible and reduce the risk of insufficient SOC and power failure.

[0103] Conversely, if the state of charge (SOC) increases and reaches the corresponding numerical requirements at the corresponding maximum power point, fixed point 3, and fixed point 2, then the feedback is sequentially transmitted from the maximum power point to fixed point 3, fixed point 2, and fixed point 1.

[0104] It should be understood that the above explanation only uses the maximum power point, fixed point 3, fixed point 2, and fixed point 1 as examples. It does not mean that the range extender's operation always needs to switch to the maximum power point. When the conditions at fixed point 3 or fixed point 2 are met, it can "return" to the next higher level to improve fuel economy and efficiency at the current vehicle speed. For example, if after the range extender operates at fixed point 2, the state of charge (SOC) is increasing, and the increase meets the threshold k3 (refer to...). Figure 9 When SOC > A - b + k3), the range extender switches from fixed point 2 to fixed point 1 operation. Correspondingly, in Figure 9In this context, the threshold of the state of charge (SOC) during the transition between the maximum power point, fixed point 3, fixed point 2, and fixed point 1 is expressed in an adaptive manner and should not be interpreted as having any other meaning. For example, A, b, c, d, e, K1, K2, and K3 are all numerical values ​​and are all greater than zero, while A < 40%.

[0105] It should be noted that in this application embodiment, only the maximum power point, fixed point 3, fixed point 2, and fixed point 1 are used as examples for illustration, and do not represent four operating points. In actual application, multiple operating points can be switched. For example, the range extender has 3 or 5 operating points, or even more. When the SOC≤A and the vehicle speed is less than the first preset vehicle speed (low speed), the range extender with 3 operating points switches between the 3 operating points. In the high-speed cruise control condition, this application embodiment only uses high-speed fixed point 3, high-speed fixed point 4, and high-speed fixed point 5 as examples for illustration, and should not be construed as an improper limitation of this application. Furthermore, for the sake of simplicity and readability, Figure 9 The terms "Central Fixed Point 4 / 5" and "High-Speed ​​Fixed Point 4" and "High-Speed ​​Fixed Point 5" are different expressions of the same meaning and should not be understood as different phrases.

[0106] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed in this application.

Claims

1. A control method for a range-extended vehicle, characterized in that, include: Obtain the vehicle speed and the state of charge (SOC) of the power battery of the range-extended vehicle; If the range-extended vehicle is in the first operating state, the range extender is started and controlled to operate at the highest efficiency point. The first operating state refers to: the vehicle speed is greater than or equal to the first preset vehicle speed, the state of charge (SOC) is less than or equal to the first threshold (S1), and the range-extended vehicle is in a constant speed cruise state. If the State of Charge (SOC) decreases to the target lower limit after the range extender operates at its highest efficiency point, then the range extender is controlled to operate at a first constant speed power point to increase the power generation of the range extender. The power generation at the first constant speed power point is greater than the power generation at the highest efficiency point, and the power generation efficiency at the first constant speed power point is less than the power generation efficiency at the highest efficiency point. Wherein, the target SOC lower limit is less than the first threshold S1.

2. The control method according to claim 1, characterized in that, After starting the range extender and controlling it to operate at its highest efficiency point, the control method further includes: If the state of charge (SOC) increases to the target threshold, the range extender is shut down and the range-extended vehicle enters EV mode, wherein the target threshold is greater than the first threshold S1.

3. The control method according to claim 1, characterized in that, After the step of controlling the range extender to operate at the first constant speed power point, the control method further includes: If the State of Charge (SOC) increases to the upper limit of the target SOC, the range extender is controlled to switch from the first constant speed power point to the highest efficiency point, wherein the upper limit of the target SOC is greater than the lower limit of the target SOC, and the upper limit of the target SOC is less than the first threshold S1.

4. The control method according to claim 1, characterized in that, After obtaining the vehicle speed and the state of charge (SOC) of the power battery of the range-extended vehicle, the control method further includes: If the range-extended vehicle is in the second operating state, the range extender is started and controlled to operate at the first power point. The second operating state refers to the vehicle speed being less than the first preset vehicle speed and the state of charge (SOC) being less than or equal to the second threshold (S2). The second threshold (S2) is less than the first threshold (S1). The first power point and the highest efficiency point are the operating conditions of the range extender at different vehicle speeds.

5. The control method according to claim 4, characterized in that, After the steps of starting the range extender and controlling the range extender to operate at the first power point, the control method further includes: If the state of charge (SOC) of the range extender decreases to a third threshold (S3) after the range extender operates at the first power point, then the range extender is controlled to operate at the second power point, wherein the power generation at the second power point is greater than the power generation at the first power point.

6. The control method according to claim 5, characterized in that, After the step of controlling the range extender to operate at the second efficiency point, the control method further includes: If the state of charge (SOC) decreases to the fourth threshold (S4) after the range extender operates at the second power point, then the range extender is controlled to operate at the maximum power point, wherein the power generation at the maximum power point is greater than the power generation at the second power point.

7. The control method according to claim 6, characterized in that, After the step of controlling the range extender to operate at its maximum power point, the control method further includes: If the state of charge (SOC) increases to the second threshold S2 after the range extender operates at the maximum power point, then the range extender is controlled to switch from the maximum power point to the first power point.

8. The control method according to claim 4, characterized in that, After the steps of starting the range extender and controlling the range extender to operate at the first power point, the control method further includes: If the state of charge (SOC) increases to the target threshold after the range extender operates at the first power point, then the range extender is shut down.

9. A control system for a range-extended vehicle, characterized in that, The control system is used to execute the control method according to any one of claims 1 to 8, and the control system includes a detection module and a control module, wherein... The detection module is used to detect the vehicle speed, state of charge (SOC), and operating status of the range-extended vehicle. The control module is used to control the range extender to operate at the highest efficiency point when the range-extended vehicle is in the first operating state, and to control the range extender to operate at the first constant speed power point after the range extender has operated at the highest efficiency point and the state of charge (SOC) has decreased to the target lower limit value. The first operating state refers to the following: the vehicle speed is greater than or equal to the first preset vehicle speed, the state of charge (SOC) is less than or equal to the first threshold S1, and the range-extended vehicle is in a constant speed cruise state.

10. The control system according to claim 9, characterized in that, The control module is also used for: When the range-extended vehicle is in the second operating state, the range extender is started and controlled to operate at the first power point, wherein the second operating state refers to: the vehicle speed is less than the first preset vehicle speed and the state of charge (SOC) is less than or equal to the second threshold (S2).

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