Engine starting control method, device and system and vehicle

Abstract

The invention provides an engine starting control method, device and system and a vehicle, and belongs to the technical field of vehicle control. According to the embodiment of the invention, when the vehicle meets the mode switching condition of switching from a pure electric four-wheel drive mode to a power dividing mode, a first synchronizer is controlled to conduct gear switching, and when the first synchronizer switches a power dividing gear, the first synchronizer is controlled to conduct gear switching; and the first motor is controlled to drag the engine through the power dividing mechanism and the clutch in sequence, and after the engine is controlled to be ignited, the clutch is controlled to be switched from the open state to the closed state by adjusting the rotating speed of the first motor. According to the embodiment of the invention, the engine is dragged by the first motor through the power dividing mechanism and the clutch in sequence, so that the engine can be quickly started without additionally arranging a starting motor, and the clutch can be controlled to be quickly closed by adjusting the rotating speed of the first motor, so that the engine can immediately output torque; while the mode switching time is shortened, faster dynamic response is realized.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle control, and particularly to an engine starting control method, device, system and vehicle. Background Art

[0002] With the rapid development of the automotive industry, in response to the national policies of energy conservation, emission reduction and carbon balance, traditional fuel vehicles are gradually moving towards hybrid vehicles. Hybrid vehicles usually have multiple driving modes including pure electric four-wheel drive mode and power split mode to adapt to different road conditions and driving demands. During the vehicle driving process, the driving modes will switch to each other under certain conditions.

[0003] When the vehicle switches from pure electric four-wheel drive mode to power split mode, the engine needs to be started. Currently, a low-voltage starting motor is usually used to start the engine. However, this method requires an additional motor to be arranged in a limited space, which not only increases the production cost, but also has the problem of poor starting effect, resulting in a longer mode switching duration, untimely engine power response, and affecting the user driving experience. Summary of the Invention

[0004] The present application provides an engine starting control method, device, system and vehicle to solve the problem that the engine starting is untimely when a hybrid vehicle switches from pure electric four-wheel drive mode to power split mode, resulting in a longer mode switching duration.

[0005] To solve the above problems, the present application adopts the following technical solutions:

[0006] In a first aspect, an embodiment of the present application provides an engine starting control method applied to a vehicle, where the vehicle includes an engine, a clutch, a first motor and a gearbox; the gearbox includes a power split mechanism, a first synchronizer and a gearbox input shaft, the engine is connected to a first input end of the power split mechanism through the clutch, the first motor is connected to a second input end of the power split mechanism, an output end of the power split mechanism is connected to the gearbox input shaft, and the first synchronizer is arranged between the first input end and the output end; the method includes:

[0007] When the vehicle meets the mode switching condition for switching from pure electric four-wheel drive mode to power split mode, controlling the first synchronizer to switch from the engaged gear to the power split gear;

[0008] When it is detected that the first synchronizer is in the power split gear, controlling the first motor to drag the engine through the power split mechanism and the clutch in sequence, so that the engine meets the ignition condition;

[0009] When the engine meets the ignition condition, control the engine to ignite; and adjust the speed of the first motor so that the clutch switches from the open state to the closed state.

[0010] In an embodiment of the present application, when the vehicle meets the mode switching condition for switching from the pure electric four-wheel drive mode to the power split mode, the step of controlling the first synchronizer to switch from the engaged gear to the power split gear includes:

[0011] When the vehicle meets the mode switching condition for switching from the pure electric four-wheel drive mode to the power split mode, adjust the torque of the first motor so that the first synchronizer meets the gear shifting condition;

[0012] When the first synchronizer meets the gear shifting condition, control the first synchronizer to switch from the engaged gear to the power split gear.

[0013] In an embodiment of the present application, the step of controlling the first motor to drive the engine through the power split mechanism and the clutch in sequence so that the engine meets the ignition condition includes:

[0014] When controlling the first motor to reach the first target motor speed, adjust the torque of the clutch so that the first motor drives the engine through the power split mechanism and the clutch in sequence;

[0015] When the current engine speed of the engine reaches the target engine speed, control the current clutch torque of the clutch to decrease to the target clutch torque;

[0016] When the current clutch torque reaches the target clutch torque, determine that the engine meets the ignition condition.

[0017] In an embodiment of the present application, the method further includes:

[0018] During the process of adjusting the torque of the clutch, based on the current clutch torque, control the first motor to perform torque compensation so that the first motor is stabilized at the first target motor speed.

[0019] In an embodiment of the present application, the step of adjusting the speed of the first motor so that the clutch switches from the open state to the closed state includes:

[0020] Based on the current engine speed of the engine, determine the second target motor speed of the first motor;

[0021] Control the first motor to follow the rotational speed of the second target motor, so that the clutch switches from the open state to the closed state.

[0022] In an embodiment of the present application, the power split mechanism includes a ring gear, a sun gear, a plurality of planet gears meshing between the ring gear and the sun gear, and a planet carrier rotatably connected to the plurality of planet gears; the planet carrier is connected to the engine as the first input end, the sun gear is connected to the first motor as the second input end, the ring gear is connected to the transmission input shaft as the output end, and the first synchronizer is arranged between the planet carrier and the ring gear;

[0023] The step of determining the second target motor speed of the first motor based on the current engine speed of the engine includes:

[0024] When the current gear position of the first synchronizer is the power split gear position, determine that the transmission ratio between the planet carrier and the sun gear is the first transmission ratio;

[0025] Based on the current engine speed and the first transmission ratio, determine the second target motor speed.

[0026] In an embodiment of the present application, the step of controlling the first motor to follow the second target motor speed, so that the clutch switches from the open state to the closed state includes:

[0027] When the first speed difference between the current motor speed of the first motor and the second target motor speed is less than the first speed difference threshold, control the clutch to switch from the open state to the slip friction state;

[0028] When the first speed difference is less than the second speed difference threshold, control the clutch to switch from the slip friction state to the closed state; wherein, the second speed difference threshold is less than the first speed difference threshold.

[0029] In a second aspect, based on the same inventive concept, an embodiment of the present application provides an engine start control device applied to a vehicle, the vehicle includes an engine, a clutch, a first motor and a transmission; the transmission includes a power split mechanism, a first synchronizer and a transmission input shaft, the engine is connected to the first input end of the power split mechanism through the clutch, the first motor is connected to the second input end of the power split mechanism, the output end of the power split mechanism is connected to the transmission input shaft, and the first synchronizer is arranged between the first input end and the output end; the device includes:

[0030] A gear shifting module, configured to control the first synchronizer to shift from the engaged gear to the power split gear when the vehicle meets the mode switching condition for switching from the pure electric four-wheel drive mode to the power split mode;

[0031] A starting control module, configured to control the first motor to drive the engine through the power split mechanism and the clutch in sequence when it is detected that the first synchronizer is in the power split gear, so that the engine meets the ignition condition;

[0032] An ignition control module, configured to control the engine to ignite when the engine meets the ignition condition; and adjust the speed of the first motor to switch the clutch from the open state to the closed state.

[0033] In an embodiment of the present application, the gear shifting module includes:

[0034] A motor torque adjustment sub-module, configured to adjust the torque of the first motor when the vehicle meets the mode switching condition for switching from the pure electric four-wheel drive mode to the power split mode, so that the first synchronizer meets the gear shifting condition;

[0035] A gear shifting sub-module, configured to control the first synchronizer to shift from the engaged gear to the power split gear when the first synchronizer meets the gear shifting condition.

[0036] In an embodiment of the present application, the starting control module includes:

[0037] A clutch torque adjustment sub-module, configured to adjust the torque of the clutch when the first motor reaches the first target motor speed, so that the first motor drives the engine through the power split mechanism and the clutch in sequence;

[0038] A clutch torque reduction sub-module, configured to control the current clutch torque of the clutch to be reduced to the target clutch torque when the current engine speed of the engine reaches the target engine speed;

[0039] An ignition condition determination sub-module, configured to determine that the engine meets the ignition condition when the current clutch torque reaches the target clutch torque.

[0040] In an embodiment of the present application, the engine starting control device further includes:

[0041] A motor torque compensation module, configured to control the first motor to perform torque compensation based on the current clutch torque during the process of adjusting the torque of the clutch, so that the first motor is stabilized at the first target motor speed.

[0042] In an embodiment of the present application, the ignition control module includes:

[0043] A motor speed determination sub-module, configured to determine a second target motor speed of the first motor based on the current engine speed of the engine;

[0044] A motor speed adjustment sub-module, configured to control the first motor to follow the second target motor speed, so that the clutch switches from an open state to a closed state.

[0045] In an embodiment of the present application, the power split mechanism includes a ring gear, a sun gear, a plurality of planet gears meshing between the ring gear and the sun gear, and a planet carrier rotatably connected to the plurality of planet gears; the planet carrier is connected to the engine as the first input end, the sun gear is connected to the first motor as the second input end, the ring gear is connected to the transmission input shaft as the output end, and the first synchronizer is disposed between the planet carrier and the ring gear;

[0046] The motor speed determination sub-module includes:

[0047] A gear ratio determination unit, configured to determine that the gear ratio between the planet carrier and the sun gear is a first gear ratio when the current gear position of the first synchronizer is the power split gear position;

[0048] A motor speed determination unit, configured to determine the target motor speed based on the current engine speed and the first gear ratio.

[0049] In an embodiment of the present application, the motor speed following sub-module includes:

[0050] A first control unit, configured to control the clutch to switch from the open state to a slip grinding state when the rotational speed difference between the current motor speed of the first motor and the target motor speed is less than a first rotational speed difference threshold;

[0051] A second control unit, configured to control the clutch to switch from the slip grinding state to a closed state when the rotational speed difference is less than a second rotational speed difference threshold; wherein, the second rotational speed difference threshold is less than the first rotational speed difference threshold.

[0052] In a third aspect, based on the same inventive concept, an embodiment of the present application provides an engine starting control system for a vehicle, which includes an engine, a clutch, a first motor, and a transmission; the transmission includes a power splitting mechanism, a first synchronizer, and a transmission input shaft, the engine is connected to a first input end of the power splitting mechanism through the clutch, the first motor is connected to a second input end of the power splitting mechanism, an output end of the power splitting mechanism is connected to the transmission input shaft, and the first synchronizer is arranged between the first input end and the output end; the system includes a vehicle controller, a transmission controller, a motor controller, and an engine controller; wherein,

[0053] The vehicle controller is configured to control the transmission controller to switch the first synchronizer from the engaged gear to the power splitting gear when the vehicle meets the mode switching condition for switching from the pure electric four-wheel drive mode to the power splitting mode;

[0054] The vehicle controller is further configured to send a motor control request to the motor controller and a clutch control request to the transmission controller when it detects that the first synchronizer is in the power splitting gear;

[0055] The motor controller is configured to control the first motor to drive the clutch through the power splitting mechanism in response to the motor control request; the transmission controller is configured to control the clutch to drive the engine in response to the clutch control request so that the engine meets the ignition condition;

[0056] The vehicle controller is further configured to send an ignition request to the engine controller when the engine meets the ignition condition, so that the engine controller controls the engine to ignite in response to the ignition request;

[0057] The vehicle controller is further configured to send a motor speed regulation request to the motor controller, so that the motor controller regulates the speed of the first motor in response to the motor speed regulation request, and the transmission controller switches the clutch from the open state to the closed state.

[0058] In a fourth aspect, based on the same inventive concept, an embodiment of the present application provides a vehicle, which includes the engine starting control system proposed in the third aspect of the present application.

[0059] Compared with the prior art, the present application has the following advantages:

[0060] An engine starting control method provided by an embodiment of the present application can, when the vehicle meets the mode switching condition for switching from the pure electric four-wheel drive mode to the power split mode, control the first synchronizer to switch from the engaged gear to the power split gear, and when the first synchronizer is in the power split gear, control the first motor to drive the engine through the power split mechanism and the clutch in sequence, and then, when the engine meets the ignition condition, control the engine to ignite and adjust the speed of the first motor to switch the clutch from the open state to the closed state. By using the first motor to drive the engine through the power split mechanism and the clutch in sequence, the embodiment of the present application can achieve rapid starting of the engine without additionally increasing a starting motor, and after the engine completes ignition, by adjusting the speed of the first motor, the clutch can be quickly closed, enabling the engine to immediately output torque, thereby effectively shortening the mode switching duration and achieving faster power response to enhance the user's driving experience. Description of the Drawings

[0061] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0062] Figure 1 It is a schematic structural diagram of a hybrid vehicle in an embodiment of the present application.

[0063] Figure 2 It is a flowchart of the steps of an engine starting control method in an embodiment of the present application.

[0064] Figure 3 It is a schematic diagram of the functional modules of an engine starting control device in an embodiment of the present application.

[0065] Figure 4 It is a schematic structural diagram of an engine starting control system in an embodiment of the present application.

[0066] Figure 5 It is a schematic structural diagram of a vehicle in an embodiment of the present application. Detailed Embodiments

[0067] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0068] Reference Figure 1 , a schematic structural diagram of a hybrid vehicle in an embodiment of the present application is shown. The hybrid vehicle is provided with an engine 101, a clutch 102, a first motor 103 and a transmission on the front axle of the vehicle; the transmission includes a power split mechanism 104, a transmission input shaft 107, a transmission output shaft 108, a first synchronizer 105 and a second synchronizer 106. The engine 101 is connected to the first input end of the power split mechanism 104 through the clutch 102, the first motor 103 is connected to the second input end of the power split mechanism 104, and the output end of the power split mechanism 104 is connected to the transmission input shaft 107.

[0069] The first synchronizer 105 is arranged between the first input end and the output end and is used to engage or disengage the first input end and the output end. Specifically, when the first synchronizer 105 is in the engaged gear, the first synchronizer 105 is used to engage the first input end and the output end; when the first synchronizer 105 is in the power split gear, the first synchronizer 105 is used to disengage the first input end and the output end. It should be noted that the first synchronizer 105 is used to control the vehicle to switch between the power split mode and other modes, that is, when the first synchronizer 105 is in the power split gear, the vehicle can be in the power split mode; when the first synchronizer 105 is in the engaged gear, the vehicle can be in other modes except the power split mode, such as the series mode, the direct drive mode or the pure electric four-wheel drive mode, etc.

[0070] The second synchronizer 106 is arranged between the transmission input shaft 107 and the transmission output shaft 108 and is used to engage or disengage the transmission input shaft 107 and the transmission output shaft 108. Specifically, when the second synchronizer 106 is in gear, the second synchronizer 106 is used to engage the transmission input shaft 107 and the transmission output shaft 108; when the second synchronizer 106 is in neutral, the second synchronizer 106 is used to disengage the transmission input shaft 107 and the transmission output shaft 108.

[0071] Since the hybrid vehicle adopting the above architecture is configured with a power split mechanism 104, and the power split mechanism 104 is simultaneously connected to the engine 101, the first motor 103 and the transmission input shaft 107, the vehicle can have multiple driving modes including the pure electric four-wheel drive mode and the power split mode. Furthermore, by changing the gear states of the clutch 102, the first synchronizer 105 and the second synchronizer 106, the vehicle can be switched between different driving modes. Specifically:

[0072] In the pure electric four-wheel drive mode, the engine 101 is in the off state, the clutch 102 is in the open state, the first synchronizer 105 is in the engaged gear, the second synchronizer 106 is in the in-gear state, and the first motor 103 and the second motor are both in the driving state. At this time, the power battery supplies power to the first motor 103 and the second motor simultaneously. The driving force output by the first motor 103 is transmitted to the power splitting mechanism 104 through the second input end. The power splitting mechanism 104 then transmits the driving force through the output end, the transmission input shaft 107, the second synchronizer 106, the transmission output shaft 108, and the front axle differential 109 to the front axle wheels; the driving force output by the second motor is transmitted to the rear axle wheels through the rear axle differential.

[0073] In the power splitting mode, the first synchronizer 105 is in the power splitting gear. At this time, the first synchronizer is in the disengaged gear state, used to disconnect the first input end and the output end. The second synchronizer 106 is in the in-gear state, the engine 101 is in the driving state, the clutch 102 is in the closed state, the first motor 103 is in the power generation state, and the second motor is in the driving state. At this time, the driving force output by the engine 101 is transmitted to the power splitting mechanism 104 through the clutch 102 and the first input end. The power splitting mechanism 104 then transmits a part of the driving force to the first motor 103 through the second input end to drive the first motor 103 to generate electricity (at this time, the first motor 103 outputs negative torque), and the generated electric energy is supplied to the power battery for charging; the power splitting mechanism 104 also transmits another part of the driving force to the transmission input shaft 107 through the output end, and the transmission input shaft 107 sequentially transmits this part of the driving force to the vehicle front axle through the second synchronizer 106, the transmission output shaft 108, and the front axle differential 109 to drive the vehicle to travel. Among them, the distribution ratio of the driving force can be set according to actual needs. That is to say, in the power splitting mode, a part of the output power of the engine 101 is used to drive the first motor 103 to charge the power battery, and another part of the output power is used to directly drive the vehicle to travel.

[0074] In the related art, when the vehicle switches from the pure electric four-wheel drive mode to the power splitting mode, the engine 101 needs to be started. Currently, a low-voltage starting motor is usually used to start the engine 101. However, this method requires an additional motor to be arranged in a limited space, which not only increases the production cost but also has the problem of poor starting effect, resulting in a long mode switching time, untimely power response of the engine 101, and affecting the user driving experience.

[0075] In view of the problem that when a hybrid vehicle switches from the pure electric four-wheel drive mode to the power split mode currently, the engine starts untimely, resulting in a relatively long mode switching duration, the present application aims to provide an engine start control method. By using the first motor 103 to drive the engine 101 through the power split mechanism 104 and the clutch 102 in sequence, the rapid start of the engine 101 can be achieved without additionally adding a starting motor. After the engine 101 completes ignition, by adjusting the speed of the first motor 103, the clutch 102 can be quickly closed, enabling the engine 101 to immediately output torque. Thus, while effectively shortening the mode switching duration, faster power response can be realized, enhancing the driving experience of users.

[0076] Referring to Figure 2 , there is shown an engine start control method of the present application, which is applied to a hybrid vehicle adopting the above architecture. The method may include the following steps:

[0077] S201: When the vehicle meets the mode switching condition for switching from the pure electric four-wheel drive mode to the power split mode, control the first synchronizer 105 to switch from the engaged gear to the power split gear.

[0078] It should be noted that the execution subject of this embodiment may be a computing service device with data processing, network communication, and program running functions, or an electronic device with the above functions, such as an on-board computer, a vehicle computer, etc., such as an ECU (Electronic Control Unit) or an HCU (Hybrid Control Unit). This embodiment will be described with the HCU as the execution subject. It should be noted that the present embodiment does not make a specific limitation on the execution subject of the vehicle.

[0079] In this embodiment, since in the pure electric four-wheel drive mode, the power source of the vehicle comes from the power battery, therefore, as the vehicle travels, the remaining power of the power battery will continuously decrease. To avoid power shortage of the power battery, the HCU will monitor the SOC (State of Charge) of the power battery, and then, when it detects that the current remaining power of the power battery is less than the power threshold, it determines that the vehicle meets the mode switching condition for switching from the pure electric four-wheel drive mode to the power split mode, and automatically controls the vehicle to switch from the pure electric four-wheel drive mode to the power split mode.

[0080] In specific implementation, after the HCU detects that the vehicle meets the mode switching condition, it will adjust the torque of the first motor 103 to reduce the torque of the first motor 103 acting on the first synchronizer 105, so as to ensure that the first synchronizer 105 can smoothly switch from the engaged gear to the power split gear.

[0081] S202: When it is detected that the first synchronizer 105 is in the power split gear position, control the first motor 103 to drive the engine 101 through the power split mechanism 104 and the clutch 102 in sequence, so that the engine 101 meets the ignition conditions.

[0082] In this embodiment, if the HCU detects that the first synchronizer 105 has been switched to the power split gear position, it will trigger the closing operation of the clutch 102, and use the first motor 103 to drive the engine 101 through the power split mechanism 104 and the clutch 102 in sequence.

[0083] It should be noted that since a power split mechanism 104 is configured between the engine 101 and the first motor 103, a structure similar to a lever can be formed. That is, when the clutch 102 is closed, the first motor 103 can transfer the output torque to the engine 101 side with the power split mechanism 104 as the fulcrum.

[0084] In a specific implementation, the HCU will send a motor control request to the motor controller, so that the motor controller responds to the motor control request and controls the first motor 103 to drive the clutch 102 through the power split mechanism 104; at the same time, the HCU will also send a clutch control request to the transmission controller, so that the transmission controller responds to the clutch control request and increases the clutch torque to control the clutch 102 to drive the engine 101. In this way, while the first motor 103 drives the clutch 102 to rotate, the clutch 102 drags the engine 101 to continuously increase its speed under the action of the clutch torque, and finally makes the engine 101 meet the ignition conditions.

[0085] S203: When the engine 101 meets the ignition conditions, control the engine 101 to ignite; and adjust the speed of the first motor 103 to switch the clutch 102 from the open state to the closed state.

[0086] In this embodiment, when the HCU detects that the engine 101 meets the ignition conditions, it will send an ignition request to the engine controller, so that the engine controller responds to the ignition request and controls the engine 101 to ignite.

[0087] It should be noted that before the clutch 102 is closed, it is necessary to control the speed difference between its two ends to be less than a pre-calibrated closing threshold, and this closing threshold needs to be a small value, ideally zero.

[0088] In this embodiment, considering that after the engine 101 is ignited, the rotational speed difference at both ends of the clutch 102 is relatively large. If it is directly closed, it may cause damage to the clutch 102 or result in a failed closing. Therefore, after the engine 101 is ignited, the HCU will use the current engine speed of the engine 101 as the control basis to adjust the rotational speed of the first motor 103, so as to reduce the rotational speed difference at both ends of the clutch 102.

[0089] In a specific implementation, the HCU sends a rotational speed adjustment request to the motor controller, so that the motor controller responds to the rotational speed adjustment request and adjusts the current motor speed of the first motor 103; and when the rotational speed difference at both ends of the clutch 102 is lower than the closing threshold, it sends a closing request to the transmission controller, so that the transmission controller responds to the closing request and controls the clutch 102 to switch from the open state to the closed state.

[0090] In this embodiment, after the HCU detects that the clutch 102 is fully closed, it will set the current driving mode of the vehicle from the pure electric four-wheel drive mode to the power split mode, and then control the engine 101, the first motor 103 and the second motor to output torque according to the torque distribution strategy in the power split mode.

[0091] Specifically, the torque distribution strategy includes the front axle torque distribution strategy and the rear axle torque output strategy. Among them, the HCU is used to execute the front axle torque distribution strategy, control the engine 101 to output a first torque with a positive value, and control the first motor 103 to output a second torque with a negative value. Here, the first torque is greater than the absolute value of the second torque. In this way, while the engine 101 directly drives the front axle of the vehicle through the power split mechanism 104, it can also drive the first motor 103 to generate electricity through the power split mechanism 104; at the same time, the HCU is also used to execute the rear axle torque output strategy, control the second motor to output a third torque with a positive value to drive the rear axle of the vehicle.

[0092] In the embodiment of the present application, after the first synchronizer 105 is switched to the power split gear, the first motor 103 is used to drag the engine 101 through the power split mechanism 104 and the clutch 102 in sequence. On the one hand, it can realize the rapid start of the engine 101 without additionally installing a starting motor, saving the layout space and reducing the production cost at the same time; on the other hand, after the engine 101 is ignited, by adjusting the rotational speed of the first motor 103, it can ensure the safety of the clutch 102 during shifting while controlling the clutch 102 to close quickly, so that the engine 101 can immediately output torque, thereby effectively shortening the mode switching duration and achieving faster power response, improving the driving experience of users.

[0093] In a feasible embodiment, S201 may specifically include the following sub-steps:

[0094] S201-1: When the vehicle meets the mode switching condition for switching from the pure electric four-wheel drive mode to the power split mode, the torque of the first motor 103 is adjusted so that the first synchronizer 105 meets the gear shifting condition.

[0095] In a specific implementation, the current motor torque of the first motor 103 can be gradually reduced to the target motor torque according to a preset torque adjustment gradient. The torque adjustment gradient represents the change amount of torque per unit time. For example, it can be set to 100 N·m / s.

[0096] It should be noted that the target motor torque represents the torque at which the first synchronizer 105 can achieve gear shifting. For example, to improve the service life of the first synchronizer 105, the target motor torque can be set to zero; or to maximize the gear shifting speed, the target motor torque can be set to the maximum torque at which gear disengagement can be achieved; or the target motor torque can be set to a torque between zero and the maximum torque.

[0097] In this embodiment, by gradually reducing the current motor torque of the first motor 103 according to the torque adjustment gradient, while achieving the adjustment of the motor torque, it can effectively avoid excessive torque change from affecting the driving smoothness of the vehicle.

[0098] In this embodiment, considering that during the process of adjusting the torque of the first motor 103, torque fluctuation may occur in the first motor 103. Therefore, to ensure the smooth gear shifting operation of the first synchronizer 105, the torque fluctuation condition of the first motor 103 will be detected.

[0099] In a specific implementation, when the HCU detects that the torque difference between the current motor torque and the target motor torque is less than the torque threshold, it will trigger the timing of the duration. When the duration is greater than the duration threshold, it indicates that the current motor torque of the first motor 103 fluctuates within a small range near the target motor torque, that is, it is in a stable operating state, and then it is determined that the first synchronizer 105 meets the gear shifting condition. The torque threshold can be set to 3 N·m, and the duration threshold can be set to 50 ms.

[0100] S201-2: When the first synchronizer 105 meets the gear shifting condition, control the first synchronizer 105 to switch from the engaged gear to the power split gear.

[0101] In this embodiment, during the process of adjusting the torque of the first motor 103, by simultaneously monitoring the current motor torque, it is possible to accurately determine whether the first synchronizer 105 meets the gear shifting condition, thereby ensuring that the first synchronizer 105 can shift gears smoothly and effectively avoiding situations such as damage to the first synchronizer 105 and gear shifting failure.

[0102] In a feasible embodiment, S202 may specifically include the following sub-steps:

[0103] S202-1: When controlling the first motor 103 to reach the first target motor speed, adjust the torque of the clutch 102 so that the first motor 103 drives the engine 101 through the power split mechanism 104 and the clutch 102 in sequence.

[0104] In this embodiment, to ensure that the first motor 103 can smoothly drive the engine 101 through the clutch 102, the HCU will first control the first motor 103 to reach the first target motor speed. For example, the first target motor speed can be set to 1300 rpm. In this way, it can effectively avoid the speed of the first motor 103 dropping to a low speed state within a short time during the process of increasing the clutch torque.

[0105] In a specific implementation, after the HCU detects that the first motor 103 reaches the first target motor speed, it will send a clutch control request containing a preset torque to the transmission controller, so that the transmission controller responds to the clutch control request, controls the clutch 102 to perform pre-oiling, and after the clutch 102 completes pre-oiling, controls the clutch torque to increase from zero to the preset torque to make the clutch 102 drive the engine 101, causing the speed of the engine 101 to gradually rise from zero.

[0106] In this embodiment, to make the current engine speed of the engine 101 rise steadily to the target engine speed, the step of adjusting the torque of the clutch 102 in S202-1 may specifically include the following sub-steps:

[0107] S202-1-1: Determine the current speed change rate of the engine 101 at the current moment and the historical speed change rate at the previous moment of the current moment.

[0108] In this embodiment, the HCU will monitor the current engine speed of the engine 101 in real time. Then, for any current moment, based on the current engine speed corresponding to the current moment and the historical engine speed corresponding to the previous acquisition moment of the current moment, calculate the current speed change rate corresponding to the current moment; thus, the current speed change rate corresponding to the current moment and the historical speed change rate corresponding to the previous moment can be calculated.

[0109] S202-1-2: Determine the target torque of the clutch 102 based on the current rotational speed change rate and the historical rotational speed change rate.

[0110] In this embodiment, based on the rotational speed change rates corresponding to two consecutive moments, the change trend of the rotational speed of the engine 101 can be determined.

[0111] It should be noted that when the current rotational speed change rate is greater than the historical rotational speed change rate, it indicates that under the drag of the clutch 102, the current engine rotational speed is rising at an increasing rate; when the current rotational speed change rate is less than the historical rotational speed change rate, it indicates that under the drag of the clutch 102, the current engine rotational speed is rising at a decreasing rate; if the current rotational speed change rate is equal to the historical rotational speed change rate, it indicates that under the drag of the clutch 102, the current engine rotational speed is rising steadily at the same rate.

[0112] In a specific implementation, the HCU will determine the adjustment torque based on the change rate difference between the current rotational speed change rate and the historical rotational speed change rate; and then determine the target torque of the clutch 102 based on the adjustment torque and the current clutch torque of the clutch 102.

[0113] In this embodiment, a look-up table between the change rate difference and the adjustment torque can be pre-constructed. Then, after calculating the change rate difference, the adjustment torque corresponding to the change rate difference can be determined by looking up the look-up table. Specifically, when the change rate difference is positive, the adjustment torque can be set to negative to reduce the current clutch torque; when the change rate difference is negative, the adjustment torque can be set to positive to increase the current clutch torque; when the change rate difference is zero, the adjustment torque can be set to zero, that is, keep the current clutch torque unchanged.

[0114] S202-1-3: Control the current clutch torque of the clutch 102 to reach the target torque.

[0115] In this embodiment, by monitoring the rotational speed change rate of the engine 101, the dynamic adjustment of the clutch torque can be realized, so that while the clutch 102 drags the engine 101, the current engine rotational speed can steadily reach the target engine rotational speed.

[0116] S202-2: When the current engine rotational speed of the engine 101 reaches the target engine rotational speed, control the current clutch torque of the clutch 102 to decrease to the target clutch torque.

[0117] In this embodiment, after the HCU detects that the current engine speed reaches the preset engine speed, for example, reaches 900 rpm, it can control the first motor 103 to exit the speed control mode. Under the action of inertia, the current engine speed of the engine 101 will further increase to the target engine speed.

[0118] It should be noted that the target engine speed represents the speed at which the engine 101 can ignite. For example, the target engine speed can be set to 950 rpm.

[0119] In this embodiment, considering that the clutch torque is relatively large at this time, if the engine 101 is directly controlled to ignite, after the engine 101 ignites, the output torque may be transmitted to the wheel end through the clutch 102 and the power split mechanism 104 in sequence, which may cause phenomena such as abnormal vehicle vibration or sudden acceleration. Therefore, before controlling the engine 101 to ignite, the HCU will control the current clutch torque to decrease to the target clutch torque. In this way, the torque output when the engine 101 ignites can be effectively blocked by the clutch 102, ensuring the driving smoothness of the vehicle during the mode switching process.

[0120] S202-3: When the current clutch torque reaches the target clutch torque, it is determined that the engine 101 meets the ignition condition.

[0121] In this embodiment, after the HCU detects that the current clutch torque has decreased to the target clutch torque, it will determine that the engine 101 meets the ignition condition, and then control the engine 101 to perform an ignition operation.

[0122] In an example, after the HCU detects that the first synchronizer 105 has been switched to the power split gear, it will control the first motor 103 to follow the first target motor speed, for example, 1300 rpm; and count the second continuous duration of the first motor 103 continuously operating in the speed range of [1250, 1300]. If the second continuous duration is greater than the second duration threshold, for example, 20 ms, it will control the clutch 102 to perform a pre-lubrication operation. After the clutch 102 completes the pre-lubrication operation, it will first control the clutch torque to increase from zero to a preset torque, for example, 15 N·m, and during the process of the engine speed rising, adjust the clutch torque in real time according to the speed change of the engine 101 until the current engine speed reaches the target engine speed, for example, 950 rpm, and then control the current clutch torque to decrease to 10 N·m; and after detecting that the current clutch torque has decreased to 10 N·m, control the engine 101 to ignite.

[0123] In a feasible embodiment, the engine start control method may further include the following steps:

[0124] S301: During the process of torque adjustment of the clutch 102, based on the current clutch torque, control the first motor 103 to perform torque compensation so that the first motor 103 stabilizes at the first target motor speed.

[0125] In this embodiment, considering that under the action of the clutch torque, the torque of the first motor 103 is not sufficient to maintain the stable speed of the first motor 103. Therefore, to maintain the speed of the first motor 103, during the process of torque adjustment of the clutch 102, the first motor 103 will be controlled to perform torque compensation based on the current clutch torque.

[0126] In a specific implementation, after receiving the current clutch torque feedback from the transmission controller, the HCU can control the first motor 103 to increase the torque by the same amount as the current clutch torque on the basis of the original torque of the first motor 103.

[0127] In a specific implementation, during the process of torque adjustment of the clutch 102, the HCU can also calculate the adjustment torque of the clutch 102 based on the speed change of the engine 101. Then, while adjusting the current clutch torque based on the adjustment torque, the torque adjustment of the first motor 103 can be synchronously achieved based on the adjustment torque. In this way, the HCU can actively perform torque compensation on the first motor 103 without waiting for the transmission controller to feedback the current clutch torque, effectively avoiding control errors caused by signal transmission delay, and then achieving torque balance to ensure that the first motor 103 can stably operate at the first target motor speed.

[0128] In a feasible embodiment, the step of adjusting the speed of the first motor 103 in S203 to switch the clutch 102 from the open state to the closed state may specifically include the following sub-steps:

[0129] S203-1: Determine the second target motor speed of the first motor 103 based on the current engine speed of the engine 101.

[0130] In this embodiment, considering that the speed control accuracy of the engine 101 is limited and speed fluctuations may occur, therefore, to ensure that during the closing process of the clutch 102, the speed difference between both ends of the clutch 102 can always be maintained at a state less than the closing threshold, the HCU will calculate the second target motor speed of the first motor 103 in real time based on the current engine speed of the engine 101 so that the clutch 102 can successfully complete the closing operation.

[0131] In this embodiment, since a power split mechanism 104 is provided between the first motor 103 and the engine 101, and different gear states of the first synchronizer 105 affect the speed ratio between the first motor 103 and the engine 101, therefore, in order to accurately calculate the second target motor speed of the first motor 103, the HCU will comprehensively consider the current engine speed of the engine 101 and the current gear position of the first synchronizer 105 to determine the second target motor speed of the first motor 103.

[0132] Continue to refer to Figure 1 , the power split mechanism 104 may specifically include a ring gear 1041, a sun gear 1042, a plurality of planet gears 1043 meshing between the ring gear 1041 and the sun gear 1042, and a planet carrier 1044 rotatably connected to the plurality of planet gears 1043; the planet carrier 1044 is connected to the engine 101 as the first input end of the power split mechanism 104, the sun gear 1042 is connected to the first motor 103 as the second input end of the power split mechanism 104, the ring gear 1041 is connected to the transmission input shaft 107 as the output end of the power split mechanism 104, and the first synchronizer 105 is provided between the planet carrier 1044 and the ring gear 1041.

[0133] In the idle electric four-wheel drive mode, the first synchronizer 105 is in the engaged gear. At this time, the planet carrier 1044 and the ring gear 1041 are in a locked state, and the clutch 102 is in an open state. The driving force of the engine 101 cannot be transmitted to the planet carrier 1044 through the clutch 102. The driving force output by the first motor 103 is sequentially transmitted to the vehicle front axle through the sun gear 1042, the plurality of planet gears 1043, the ring gear 1041, the transmission input shaft 107, the second synchronizer 106, the transmission output shaft 108, and the front axle differential 109 to drive the vehicle to travel.

[0134] In the power split mode, the first synchronizer 105 is in the power split gear. At this time, the planet carrier 1044 and the ring gear 1041 are in a disconnected state, and the clutch 102 is in a closed state. The driving force output by the engine 101 is transmitted to the planet carrier 1044 through the clutch 102. The planet carrier 1044 will transmit a part of the driving force to the first motor 103 through the plurality of planet gears 1043 and the sun gear 1042 in sequence to drive the first motor 103 to charge the power battery. The first motor 103 is in a power generation state at this time; at the same time, since the second synchronizer 106 is in the in-gear state, therefore, the planet carrier 1044 will transmit another part of the driving force to the vehicle front axle through the plurality of planet gears 1043, the ring gear 1041, the transmission input shaft 107, the second synchronizer 106, the transmission output shaft 108, and the front axle differential 109 in sequence to drive the vehicle to travel.

[0135] Based on the above structure, S203-1 may specifically include the following sub-steps:

[0136] S203-1-1: When the current gear position of the first synchronizer 105 is the power split gear position, determine that the speed ratio between the planet carrier 1044 and the sun gear 1042 is the first speed ratio.

[0137] In this embodiment, considering that the speed ratio between the planet carrier 1044 and the ring gear 1041 is different when the first synchronizer 105 is in different gear positions. Among them, when the current gear position of the first synchronizer 105 is the power split gear position, the speed ratio between the planet carrier 1044 and the ring gear 1041 is the second speed ratio. Furthermore, by combining the third speed ratio between the ring gear 1041 and the sun gear 1042, the speed ratio between the planet carrier 1044 and the sun gear 1042 can be calculated as the first speed ratio.

[0138] S203-1-2: Based on the current engine speed and the first speed ratio, determine the second target motor speed.

[0139] In this embodiment, after the HCU calculates the first speed ratio, it can combine the current engine speed of the engine 101 to determine the second target motor speed that the first motor 103 needs to reach currently.

[0140] In specific implementation, when the HCU sends a speed control request including the second target motor speed to the motor controller, it will also send a speed control flag bit to the motor controller, so that the motor controller controls the first motor 103 to switch from the torque control mode to the speed control mode to achieve precise control of the speed of the first motor 103.

[0141] In this embodiment, after the motor controller receives the speed control request and switches to the speed control mode, it will activate the PI (proportional-integral) speed loop for the first motor 103 to control the current motor speed of the first motor 103 to follow the second target motor speed in a closed-loop control manner.

[0142] In specific implementation, a preset PI adjustment strategy can be used to achieve closed-loop control of the motor speed. Specifically, the motor controller is built-in with a proportional controller and an integral controller. The motor controller will first calculate the speed difference between the second target motor speed and the current motor speed, and then input the current motor speed and the speed difference into the proportional controller, and a proportional adjustment value can be output; input the current motor speed and the speed difference into the integral controller, and an integral adjustment value can be output; and then based on the proportional adjustment value and the integral adjustment value, the speed of the first motor 103 is adjusted.

[0143] In this embodiment, by comprehensively considering the current gear position of the first synchronizer 105 and the speed ratio between the first motor 103 and the engine 101, an accurate calculation of the second target motor speed can be achieved. At the same time, through the closed-loop control of the motor speed, rapid and precise control of the current motor speed can be realized, thereby effectively balancing the speed difference between the two ends of the clutch 102 and ensuring that the clutch 102 can be smoothly closed.

[0144] In specific implementation, to achieve the rapid closing of the clutch 102, S203-2 may specifically include the following sub-steps:

[0145] S203-2-1: When the speed difference between the current motor speed of the first motor 103 and the second target motor speed is less than the first speed difference threshold, control the clutch 102 to switch from the open state to the slip grinding state.

[0146] In this embodiment, during the process of adjusting the torque of the first motor 103, the current motor speed will continuously approach the second target motor speed. If the HCU detects that the speed difference between the current motor speed and the second target motor speed is less than the first speed difference threshold, it will send a speed deactivation request to the motor controller, so that the motor controller responds to this speed deactivation request and exits the PI speed loop for the first motor 103; at the same time, increase the current clutch torque of the clutch 102 to make the clutch 102 switch from the open state to the slip grinding state.

[0147] S203-2-2: When the speed difference is less than the second speed difference threshold, control the clutch 102 to switch from the slip grinding state to the closed state.

[0148] In this embodiment, although the motor controller exits the PI speed loop for the first motor 103, due to inertia, the current motor speed will still continue to approach the second target motor speed. If the HCU detects that the speed difference between the current motor speed and the second target motor speed is less than the second speed difference threshold, it will send a closing instruction to the transmission controller, so that the transmission controller responds to the closing instruction and controls the clutch 102 to perform a closing operation to switch from the slip grinding state to the closed state. Among them, the second speed difference threshold is less than the first speed difference threshold.

[0149] In one example, the first rotational speed difference threshold is set to 100 rpm, and the second rotational speed difference threshold is set to 50 rpm. When the HCU detects that the rotational speed difference between the current motor speed and the second target motor speed is less than 100 rpm, it will exit the rotational speed control for the first motor 103 and control the clutch 102 to enter the torque control state, and then control the clutch 102 to be in a pre-sliding state in advance. In this way, when the first motor 103 further reduces the rotational speed difference to less than 50 rpm under the action of inertia, the clutch 102 can complete the closing in a very short time.

[0150] In this embodiment, after the HCU detects that the clutch 102 is fully closed, it will set the current driving mode of the vehicle from the idle electric four-wheel drive mode to the power split mode, and then control the engine 101, the first motor 103 and the second motor to output torque according to the torque distribution strategy in the power split mode.

[0151] In this embodiment, by controlling the clutch 102 to be in a pre-sliding state in advance, the closing speed of the clutch 102 can be effectively increased, and further the mode switching duration can be shortened.

[0152] Second, based on the same inventive concept, referring to Figure 3 , an engine start control device 300 is provided in an embodiment of the present application, which is applied to a vehicle. The vehicle includes an engine 101, a clutch 102, a first motor 103 and a transmission; the transmission includes a power split mechanism 104, a first synchronizer 105 and a transmission input shaft 107. The engine 101 is connected to the first input end of the power split mechanism 104 through the clutch 102, the first motor 103 is connected to the second input end of the power split mechanism 104, the output end of the power split mechanism 104 is connected to the transmission input shaft 107, and the first synchronizer 105 is arranged between the first input end and the output end; the engine start control device 300 includes:

[0153] A gear shift module 301, configured to control the first synchronizer 105 to switch from the engaged gear to the power split gear when the vehicle meets the mode switching condition for switching from the pure electric four-wheel drive mode to the power split mode;

[0154] A start control module 302, configured to control the first motor 103 to drag the engine 101 through the power split mechanism 104 and the clutch 102 in sequence when detecting that the first synchronizer 105 is in the power split gear, so that the engine 101 meets the ignition condition;

[0155] An ignition control module 303, configured to control the engine 101 to ignite when the engine 101 meets the ignition condition; and adjust the rotational speed of the first motor 103 to switch the clutch 102 from the open state to the closed state.

[0156] In an embodiment of the present application, the gear shifting module 301 includes:

[0157] A motor torque adjustment sub-module, configured to adjust the torque of the first motor 103 when the vehicle meets the mode switching condition for switching from the pure electric four-wheel drive mode to the power split mode, so that the first synchronizer 105 meets the gear shifting condition;

[0158] A gear shifting sub-module, configured to control the first synchronizer 105 to switch from the engaged gear to the power split gear when the first synchronizer 105 meets the gear shifting condition.

[0159] In an embodiment of the present application, the start control module 302 includes:

[0160] A clutch torque adjustment sub-module, configured to adjust the torque of the clutch 102 when controlling the first motor 103 to reach the first target motor speed, so that the first motor 103 drives the engine 101 through the power split mechanism 104 and the clutch 102 in sequence;

[0161] A clutch torque reduction sub-module, configured to control the current clutch torque of the clutch 102 to be reduced to the target clutch torque when the current engine speed of the engine 101 reaches the target engine speed;

[0162] An ignition condition determination sub-module, configured to determine that the engine 101 meets the ignition condition when the current clutch torque reaches the target clutch torque.

[0163] In an embodiment of the present application, the engine start control device 300 further includes:

[0164] A motor torque compensation module, configured to control the first motor 103 to perform torque compensation based on the current clutch torque during the process of adjusting the torque of the clutch 102, so that the first motor 103 is stabilized at the first target motor speed.

[0165] In an embodiment of the present application, the ignition control module 303 includes:

[0166] A motor speed determination sub-module, configured to determine the second target motor speed of the first motor 103 based on the current engine speed of the engine 101;

[0167] A motor speed adjustment sub-module, configured to control the first motor 103 to follow the second target motor speed, so that the clutch 102 switches from the open state to the closed state.

[0168] In an embodiment of the present application, the power splitting mechanism 104 includes a ring gear 1041, a sun gear 1042, a plurality of planet gears 1043 meshing between the ring gear 1041 and the sun gear 1042, and a planet carrier 1044 rotatably connected to the plurality of planet gears 1043; the planet carrier 1044 is connected to the engine 101 as the first input end of the power splitting mechanism 104, the sun gear 1042 is connected to the first motor 103 as the second input end of the power splitting mechanism 104, the ring gear 1041 is connected to the transmission input shaft 107 as the output end of the power splitting mechanism 104, and the first synchronizer 105 is arranged between the planet carrier 1044 and the ring gear 1041;

[0169] The motor speed determination sub-module includes:

[0170] A gear ratio determination unit, configured to determine that the gear ratio between the planet carrier and the sun gear is a first gear ratio when the current gear position of the first synchronizer 105 is a power splitting gear position;

[0171] A motor speed determination unit, configured to determine a target motor speed based on the current engine speed and the first gear ratio.

[0172] In an embodiment of the present application, the motor speed following sub-module includes:

[0173] A first control unit, configured to control the clutch 102 to switch from an open state to a slip grinding state when the speed difference between the current motor speed of the first motor 103 and the target motor speed is less than a first speed difference threshold;

[0174] A second control unit, configured to control the clutch 102 to switch from a slip grinding state to a closed state when the speed difference is less than a second speed difference threshold; wherein, the second speed difference threshold is less than the first speed difference threshold.

[0175] It should be noted that the specific implementation manner of the engine start control device 300 in the embodiment of the present application refers to the specific implementation manner of the engine start control method proposed in the first aspect of the foregoing embodiment of the present application, which will not be elaborated herein.

[0176] In the third aspect, based on the same inventive concept, refer to Figure 4, an embodiment of the present application provides an engine starting control system 400, which is applied to a vehicle. The vehicle includes an engine 101, a clutch 102, a first motor 103 and a transmission; the transmission includes a power splitting mechanism 104, a first synchronizer 105 and a transmission input shaft 107. The engine 101 is connected to the first input end of the power splitting mechanism 104 through the clutch 102, the first motor 103 is connected to the second input end of the power splitting mechanism 104, the output end of the power splitting mechanism 104 is connected to the transmission input shaft 107, and the first synchronizer 105 is arranged between the first input end and the output end; the system includes a vehicle controller 401, a transmission controller 402, a motor controller 403 and an engine controller 404; wherein,

[0177] The vehicle controller 401 is configured to control the transmission controller 402 to switch the first synchronizer 105 from the engaged gear to the power splitting gear when the vehicle meets the mode switching condition for switching from the pure electric four-wheel drive mode to the power splitting mode;

[0178] The vehicle controller 401 is further configured to send a motor control request to the motor controller 403 and send a clutch control request to the transmission controller 402 when it is detected that the first synchronizer 105 is in the power splitting gear;

[0179] The motor controller 403 is configured to control the first motor 103 to drive the clutch 102 through the power splitting mechanism 104 in response to the motor control request; the transmission controller 402 is configured to control the clutch 102 to drive the engine 101 in response to the clutch control request so that the engine 101 meets the ignition condition;

[0180] The vehicle controller 401 is further configured to send an ignition request to the engine controller 404 when the engine 101 meets the ignition condition, so that the engine controller 404 controls the engine 101 to ignite in response to the ignition request;

[0181] The vehicle controller 401 is further configured to send a motor speed adjustment request to the motor controller 403, so that the motor controller 403 adjusts the speed of the first motor 103 in response to the motor speed adjustment request, so that the transmission controller 402 switches the clutch 102 from the open state to the closed state.

[0182] It should be noted that the specific implementation manner of the engine starting control system 400 in the embodiment of the present application refers to the specific implementation manner of the engine starting control method proposed in the first aspect of the present application, which will not be elaborated here.

[0183] Fourthly, based on the same inventive concept, refer to Figure 5, an embodiment of the present application provides a vehicle 500, including the engine start control system 400 proposed in the third aspect of the present application.

[0184] It should be noted that the specific implementation of the vehicle 500 in the embodiment of the present application refers to the specific implementation of the engine start control system 400 proposed in the third aspect of the embodiment of the present application, which will not be elaborated here.

[0185] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a device, or a computer program product. Therefore, the embodiments of the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the embodiments of the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0186] The embodiments of the present invention are described with reference to the flowcharts and / or block diagrams of methods, terminal devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal devices generate for implementing in the process Figure 1 a process or multiple processes and / or blocks Figure 1 a block or multiple blocks the device with the specified functions.

[0187] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing terminal device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured product including an instruction device, and the instruction device realizes in the process Figure 1 a process or multiple processes and / or blocks Figure 1 a block or multiple blocks the specified functions.

[0188] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal device, so that a series of operation steps are executed on the computer or other programmable terminal device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable terminal device provide steps for implementing in the process Figure 1 a process or multiple processes and / or blocks Figure 1 a block or multiple blocks the specified functions.

[0189] Although the preferred embodiments of the embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they learn the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0190] Finally, it should also be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or terminal device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or terminal device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or terminal device comprising the element.

[0191] The above has introduced in detail a method, device, system and vehicle for engine start control provided by the present invention. Specific examples are used in this text to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. An engine starting control method, characterized in that, Applied to a vehicle, the vehicle includes an engine, a clutch, a first motor, and a transmission; the transmission includes a power split mechanism, a first synchronizer, and a transmission input shaft, the engine is connected to a first input end of the power split mechanism through the clutch, the first motor is connected to a second input end of the power split mechanism, an output end of the power split mechanism is connected to the transmission input shaft, and the first synchronizer is arranged between the first input end and the output end; the method includes: When the vehicle meets the mode switching condition for switching from the pure electric four-wheel drive mode to the power split mode, control the first synchronizer to switch from the engaged gear to the power split gear; When it is detected that the first synchronizer is in the power split gear, control the first motor to drag the engine through the power split mechanism and the clutch in sequence, so that the engine meets the ignition condition; When the engine meets the ignition condition, control the engine to ignite; and adjust the speed of the first motor to make the clutch switch from the open state to the closed state.

2. The engine starting control method according to claim 1, wherein, When the vehicle meets the mode switching condition for switching from the pure electric four-wheel drive mode to the power split mode, the step of controlling the first synchronizer to switch from the engaged gear to the power split gear includes: When the vehicle meets the mode switching condition for switching from the pure electric four-wheel drive mode to the power split mode, adjust the torque of the first motor to make the first synchronizer meet the gear shifting condition; When the first synchronizer meets the gear shifting condition, control the first synchronizer to switch from the engaged gear to the power split gear.

3. The engine starting control method according to claim 1, wherein, The step of controlling the first motor to drag the engine through the power split mechanism and the clutch in sequence, so that the engine meets the ignition condition includes: When controlling the first motor to reach the first target motor speed, adjust the torque of the clutch to make the first motor drag the engine through the power split mechanism and the clutch in sequence; When the current engine speed of the engine reaches the target engine speed, control the current clutch torque of the clutch to decrease to the target clutch torque; When the current clutch torque reaches the target clutch torque, determine that the engine meets the ignition condition.

4. The engine starting control method according to claim 3, wherein The method further includes: During the process of adjusting the torque of the clutch, based on the current clutch torque, control the first motor to perform torque compensation to make the first motor stable at the first target motor speed.

5. The engine starting control method according to claim 1, wherein, The step of adjusting the speed of the first motor to make the clutch switch from the open state to the closed state includes: Based on the current engine speed of the engine, determine the second target motor speed of the first motor; Control the first motor to follow the second target motor speed to make the clutch switch from the open state to the closed state.

6. The engine starting control method according to claim 5, characterized in that The power split mechanism includes a ring gear, a sun gear, a plurality of planet gears meshing between the ring gear and the sun gear, and a planet carrier rotatably connected to the plurality of planet gears; the planet carrier is connected to the engine as the first input end, the sun gear is connected to the first motor as the second input end, the ring gear is connected to the transmission input shaft as the output end, and the first synchronizer is arranged between the planet carrier and the ring gear; The step of determining the second target motor speed of the first motor based on the current engine speed of the engine includes: When the current gear position of the first synchronizer is the power split gear position, determining that the speed ratio between the planet carrier and the sun gear is the first speed ratio; Based on the current engine speed and the first speed ratio, determining the second target motor speed.

7. The engine starting control method according to claim 5, wherein The step of controlling the first motor to follow the second target motor speed so that the clutch switches from the open state to the closed state includes: When the first speed difference between the current motor speed of the first motor and the second target motor speed is less than the first speed difference threshold, controlling the clutch to switch from the open state to the slip grinding state; When the first speed difference is less than the second speed difference threshold, controlling the clutch to switch from the slip grinding state to the closed state; wherein, the second speed difference threshold is less than the first speed difference threshold.

8. An engine starting control device, characterized in that, Applied to a vehicle, the vehicle includes an engine, a clutch, a first motor and a transmission; the transmission includes a power split mechanism, a first synchronizer and a transmission input shaft, the engine is connected to the first input end of the power split mechanism through the clutch, the first motor is connected to the second input end of the power split mechanism, the output end of the power split mechanism is connected to the transmission input shaft, and the first synchronizer is arranged between the first input end and the output end; the device includes: A gear position switching module, configured to control the first synchronizer to switch from the engaged gear position to the power split gear position when the vehicle meets the mode switching condition for switching from the pure electric four-wheel drive mode to the power split mode; A starting control module, configured to control the first motor to drag the engine through the power split mechanism and the clutch in sequence when it is detected that the first synchronizer is in the power split gear position, so that the engine meets the ignition condition; An ignition control module, configured to control the engine to ignite when the engine meets the ignition condition; and adjust the speed of the first motor to make the clutch switch from the open state to the closed state.

9. An engine starting control system, characterized in that, Applied to a vehicle, the vehicle includes an engine, a clutch, a first motor and a transmission; the transmission includes a power split mechanism, a first synchronizer and a transmission input shaft, the engine is connected to a first input end of the power split mechanism through the clutch, the first motor is connected to a second input end of the power split mechanism, an output end of the power split mechanism is connected to the transmission input shaft, and the first synchronizer is arranged between the first input end and the output end; the system includes a vehicle controller, a transmission controller, a motor controller and an engine controller; wherein, the vehicle controller is configured to control the transmission controller to switch the first synchronizer from the engaged gear to the power split gear when the vehicle meets the mode switching condition for switching from the pure electric four-wheel drive mode to the power split mode; the vehicle controller is further configured to send a motor control request to the motor controller and send a clutch control request to the transmission controller when it is detected that the first synchronizer is in the power split gear; the motor controller is configured to control the first motor to drive the clutch through the power split mechanism in response to the motor control request; the transmission controller is configured to control the clutch to drive the engine in response to the clutch control request so that the engine meets the ignition condition; the vehicle controller is further configured to send an ignition request to the engine controller when the engine meets the ignition condition, so that the engine controller controls the engine to ignite in response to the ignition request; the vehicle controller is further configured to send a motor speed adjustment request to the motor controller, so that the motor controller adjusts the speed of the first motor in response to the motor speed adjustment request, so that the transmission controller switches the clutch from the open state to the closed state.

10. A vehicle, characterized in that, Including the engine starting control system according to claim 9.

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