Hybrid vehicle and its control method, device, and medium for parking crankshaft position

Abstract

The present invention discloses a hybrid vehicle and a control method, device, and medium for the parking crankshaft position. When a parking instruction is obtained, the output torque of the engine is controlled to decrease, and the generator is controlled to drive the engine to rotate until the engine runs out of fuel. The rotation speed of the generator driving the engine is maintained at a target speed, and the pressure value of the intake manifold is adjusted to a target pressure value. When the pressure value of the intake manifold is the target pressure value, the output torque of the generator and the rotation speed of the engine both show a downward trend, and the current output torque of the generator and the current rotation speed of the engine are obtained in real time. According to the current output torque of the generator and the current rotation speed of the engine, the crankshaft position is adjusted to the target crankshaft position. By adopting the above solution, the engine crankshaft position can be quickly adjusted to the target position during the parking process.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive power, and particularly to a hybrid vehicle and a control method, device, and medium for the parking crankshaft position thereof. Background Art

[0002] In congested traffic conditions, a vehicle often stays in an idle stop state and may start at any time. To improve the starting smoothness during the starting process, it is necessary to adjust the engine crankshaft position to the target position as quickly as possible during the stopping process.

[0003] The prior art usually applies a certain torque to the generator after the engine speed reaches 0, causing the generator to drive the engine to rotate, and finally adjusting the engine crankshaft position to the target position. However, this method starts to adjust the crankshaft position after the engine speed reaches 0. Since the static friction of the crankshaft rotating assembly is much greater than the sliding friction, the initial adjustment torque of the generator is relatively large, and the excessive adjustment torque may cause fluctuations in the crankshaft position, prolonging the time required for final stabilization. Summary of the Invention

[0004] The present invention provides a control method for the parking crankshaft position of a hybrid vehicle, which realizes the adjustment of the crankshaft position during the stopping process, can greatly reduce the torque required for crankshaft position adjustment, and thus can quickly and stably adjust the crankshaft position to the target crankshaft position.

[0005] According to one aspect of the present invention, there is provided a control method for the parking crankshaft position of a hybrid vehicle, including:

[0006] When a parking instruction of the hybrid vehicle is obtained, controlling the output torque of the engine of the hybrid vehicle to decrease, and controlling the generator of the hybrid vehicle to drive the engine to rotate;

[0007] When the output torque of the engine decreases to the fuel cut-off torque, controlling the engine to cut off fuel, and controlling the rotation speed of the generator driving the engine to be maintained at the target speed;

[0008] When the engine speed is the target speed, adjusting the pressure value of the intake manifold of the engine to the target pressure value;

[0009] When the pressure value of the intake manifold is the target pressure value, controlling both the output torque of the generator and the engine speed to show a downward trend;

[0010] During the process of reducing the output torque of the generator and the engine speed, the current output torque of the generator and the current engine speed are obtained in real time;

[0011] Adjust the crankshaft position of the engine to a target crankshaft position according to the current output torque of the generator and the current rotational speed of the engine.

[0012] Optionally, when the rotational speed of the engine is the target rotational speed, adjusting the pressure value of the intake manifold of the engine to a target pressure value includes:

[0013] When the rotational speed of the engine is the target rotational speed, obtain in real time the current pressure value of the intake manifold of the engine;

[0014] According to the difference between the current pressure value and the target pressure value, adjust the opening degree value of the throttle valve in the intake manifold until the current pressure value of the intake manifold reaches the target pressure value.

[0015] Optionally, according to the difference between the current pressure value and the target pressure value, adjusting the opening degree value of the throttle valve in the intake manifold until the current pressure value of the intake manifold reaches the target pressure value includes:

[0016] Obtain the target pressure value of the intake manifold and the ambient pressure value of the environment where it is located;

[0017] According to the ambient pressure value and the target pressure value, determine the target opening degree value of the throttle valve in the intake manifold;

[0018] Control the opening degree value of the throttle valve in the intake manifold to be adjusted to the target opening degree value;

[0019] According to the difference between the current pressure value and the target pressure value, based on the PI control algorithm, adjust the opening degree value of the throttle valve in the intake manifold until the current pressure value is the target pressure value.

[0020] Optionally, obtaining the target pressure value of the intake manifold includes:

[0021] When the engine is undergoing a shutdown test, control the motor to drive the engine to rotate at a rotational speed that maintains the target rotational speed;

[0022] Adjust the opening degree of the throttle valve in the intake manifold until the pressure in the intake manifold is a preset pressure;

[0023] Control the output torque of the generator to be reduced to 0, and obtain in real time the current rotational speed of the engine and the crankshaft position of the engine;

[0024] When the current rotational speed of the engine is reduced to 0, determine whether the crankshaft position of the engine is a preset crankshaft position;

[0025] If so, determine the preset pressure as the target pressure value.

[0026] Optionally, obtaining the target pressure value of the intake manifold further includes:

[0027] If the crankshaft position of the engine does not reach the preset crankshaft position, adjust the preset pressure by a preset adjustment amount, and return to execute adjusting the opening degree of the throttle valve in the intake manifold until the pressure of the intake manifold is the preset pressure until when the current speed of the engine decreases to 0, determine whether the crankshaft position of the engine is the preset crankshaft position in each step.

[0028] Optionally, adjusting the crankshaft position of the engine to the target crankshaft position according to the current output torque of the generator and the current speed of the engine includes:

[0029] Judge whether the current speed of the engine is less than or equal to the first preset speed;

[0030] If so, obtain the current crankshaft position and the current crankshaft acceleration of the engine in real time;

[0031] Determine the predicted crankshaft position of the engine according to the current crankshaft position and the current crankshaft acceleration;

[0032] According to the difference between the predicted crankshaft position and the target crankshaft position, based on the P control algorithm, adjust the output torque of the generator until the current speed of the engine is 0 and the crankshaft position of the engine is the target crankshaft position.

[0033] Optionally, the engine is a four-stroke four-cylinder engine; the target crankshaft position is the normalized position of the target crankshaft positions corresponding to the compression cylinders of the engine;

[0034] Obtaining the current crankshaft position of the engine includes:

[0035] Obtain the actual crankshaft positions corresponding to the compression cylinders of the engine;

[0036] Normalize each of the actual crankshaft positions, and determine the normalized crankshaft position as the current crankshaft position of the engine.

[0037] According to another aspect of the present invention, a hybrid vehicle is provided, including: an engine, a generator, and a vehicle controller;

[0038] The vehicle controller is used to execute the control method for the parking crankshaft position of the above hybrid vehicle.

[0039] According to another aspect of the present invention, there is provided a computer-readable storage medium storing computer instructions for causing a processor to implement the above control method for the crankshaft position of a hybrid vehicle during parking when executed.

[0040] In the technical solution of the present invention, when a parking instruction is obtained, the output torque of the engine is controlled to decrease, and the generator is controlled to drive the engine to rotate until the engine cuts off fuel. The rotation speed of the generator driving the engine is maintained at a target speed, and the pressure value of the intake manifold is adjusted to a target pressure value. When the pressure value of the intake manifold is the target pressure value, the output torque of the generator and the rotation speed of the engine both show a downward trend, and the current output torque of the generator and the current rotation speed of the engine are obtained in real time. According to the current output torque of the generator and the current rotation speed of the engine, the crankshaft position is adjusted to the target crankshaft position, so as to solve the problem that the static friction force of the crankshaft rotating assembly is much greater than the sliding friction force when the crankshaft position is adjusted after the engine speed reaches 0, which increases the time required to adjust the crankshaft position to the target position. In the present invention, the crankshaft position is adjusted during the engine shutdown process, and the crankshaft position can be accurately, quickly and stably adjusted to the target crankshaft position, providing conditions for the smoothness and stability of the next engine startup.

[0041] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0043] Figure 1 is a schematic structural diagram of a dual-motor hybrid system provided by an embodiment of the present invention;

[0044] Figure 2 is a flowchart of a control method for the crankshaft position of a hybrid vehicle during parking provided by Embodiment 1 of the present invention;

[0045] Figure 3 is a schematic structural diagram of an engine control system provided by Embodiment 1 of the present invention;

[0046] Figure 4 is a flowchart of a control method for the crankshaft position of a hybrid vehicle during parking provided by Embodiment 2 of the present invention;

[0047] Figure 5 It is a flowchart of a control method for the parking crankshaft position of a hybrid vehicle provided in Embodiment 3 of the present invention;

[0048] Figure 6 It is a flowchart of a control method for the parking crankshaft position of a hybrid vehicle provided in Embodiment 4 of the present invention;

[0049] Figure 7 It is a schematic structural diagram of a control device for the parking crankshaft position of a hybrid vehicle provided in Embodiment 5 of the present invention. Detailed implementation manners

[0050] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0051] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above accompanying drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily need to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0052] A hybrid vehicle can be specifically understood as a vehicle including a dual-motor hybrid system, such as Figure 1As shown, the dual-motor hybrid power system 100 of a hybrid vehicle at least includes an engine 101 and a generator 102; in addition, the hybrid vehicle may also include a torsional damper 103, a clutch 104, etc. When the clutch 104 is disengaged, the hybrid vehicle is in a series drive mode, and the rotational speed of the engine 101 is decoupled from the vehicle speed, so that the engine 101 operates in the economic zone; when the clutch 104 is engaged, the hybrid vehicle is in a parallel drive mode, and the rotational speed of the engine 101 has a fixed speed ratio relationship with the vehicle speed; the torsional damper 103 between the engine 101 and the generator 102 can reduce the influence of the torque fluctuation of the engine 101 on the drive system; during the process of the generator 102 driving the engine 101 to rotate, the driving torque output by the generator 10 is transmitted to the engine 101 after passing through the torsional damper 103. During this driving process, both the driving torque of the generator 102 and the driving reaction force of the engine 101 act on the torsional damper 103, resulting in resonance of the torsional vibration damper 103. If the driving reaction force of the engine 101 can be reduced during the driving process, it will help to reduce the resonance of the torsional damper 103 during the engine starting process. If the crankshaft position of the engine before engine starting is the target crankshaft position, the driving reaction force of the engine 101 during the driving process can be effectively reduced, thereby ensuring a smooth and stable engine starting.

[0053] Embodiment 1

[0054] Figure 2 It is a flowchart of a control method for the parking crankshaft position of a hybrid vehicle provided in Embodiment 1 of the present invention. This embodiment is applicable to the situation of controlling the crankshaft position of the engine when the hybrid vehicle is driving and parking. This method can be executed by a control device for the parking crankshaft position of the hybrid vehicle. The device can be implemented in the form of hardware and / or software, and the device can be configured in the vehicle controller of the hybrid vehicle. As Figure 2 shown, the method includes:

[0055] S110. When a parking instruction of the hybrid vehicle is obtained, control the output torque of the engine of the hybrid vehicle to decrease, and control the generator of the hybrid vehicle to drive the engine to rotate.

[0056] Among them, the parking instruction of the hybrid vehicle may include, but is not limited to, the displacement information of the brake pedal, the engine-off information, etc. At this time, the engine should change from the normal operating state to the idle state or the shutdown state to achieve the purpose of energy conservation and emission reduction. Thus, when the parking instruction of the hybrid vehicle is received, the output torque of the engine can be controlled to decrease to the fuel cut-off torque, so that the engine no longer outputs power. During the process of the output torque of the engine decreasing, to ensure that the engine does not stop but continues to rotate at a certain speed, the engine can be driven by the generator. At this time, the engine acts as a load and is driven by the generator to rotate.

[0057] S120. When the output torque of the engine drops to the cut-off torque, control the engine to cut off fuel, and control the rotational speed of the generator driving the engine to maintain at the target speed.

[0058] Specifically, during the process of the engine running normally and outputting torque, the compressed air entering the engine cylinders controls the fuel injectors of each cylinder to inject fuel, which mixes with the gas in the cylinders and burns, enabling the pistons in the cylinders to reciprocate, controlling the rotation of the engine crankshaft, and enabling the engine to have the corresponding output torque. When the engine stops, it is necessary to gradually reduce the output torque of the engine until the output torque of the engine drops to the cut-off torque, at which point the fuel injectors in the engine can be controlled to stop injecting fuel, putting the engine in a fuel cut-off state; at this time, the power for the engine to rotate comes from the generator. The engine acts as a load, and the generator can drive the engine to rotate, maintaining the rotational speed of the engine at the corresponding target speed. Among them, the target speed can be greater than the minimum idle speed n0 of the engine. For example, it can be n0 + Δn, Δn can be 300 rpm, and n0 + Δn can be 100 rpm.

[0059] S130. When the rotational speed of the engine is the target speed, adjust the pressure value of the engine intake manifold to the target pressure value.

[0060] Among them, the intake manifold can be specifically understood as the gas transmission pipeline between the throttle valve and the engine intake valves. It can distribute the air-fuel mixture to the intake ports of each cylinder. The pressure in the intake manifold can be controlled by the engine control system.

[0061] Specifically, Figure 3 is a schematic structural diagram of an engine control system provided by an embodiment of the present invention, as Figure 3As shown in the figure, the engine control system 200 includes a vehicle controller 202, an engine controller 109, a pressure detection sensor 106, a throttle valve 105, an exhaust turbocharger 108, and a position detection sensor 107. The vehicle controller 202 and the engine controller 109 can communicate via the CAN bus 201. The throttle valve 105 is disposed in the intake manifold and can control the flow rate of the gas entering the intake manifold. A pressure detection sensor 106 is also disposed on the intake manifold to detect the pressure information in the intake manifold. In addition, the position detection sensor 107 is disposed on the flywheel housing and can determine the crankshaft position of the engine by obtaining the rotation information of the flywheel. The exhaust turbocharger 108 is disposed in the exhaust pipe and can control the intake density entering the intake manifold. Among them, the pressure value of the intake manifold is controlled by the opening degree of the throttle valve 105. The smaller the opening degree of the throttle valve 105, the greater the vacuum degree of the intake manifold, and the smaller the pressure value of the intake manifold. Conversely, the larger the throttle opening, the smaller the vacuum degree of the intake manifold, and the greater the pressure of the intake manifold. The opening degree of the throttle valve can be controlled by the vehicle controller 202 through the engine controller 109. Thus, when the engine maintains the target speed, the pressure value in the intake manifold can be adjusted by controlling the opening degree of the throttle valve, so that the pressure value in the intake manifold can reach the target pressure value.

[0062] S140. When the pressure value of the intake manifold is the target pressure value, control the output torque of the generator and the engine speed to both show a downward trend.

[0063] Specifically, after the engine cuts off fuel, if the engine speed is at the target speed and the intake manifold pressure value is the target pressure, the opening degree of the throttle valve at this time can be fixed. At this time, if the output torque of the generator is cleared to zero, the engine speed will decrease to 0 based on the piston compression reaction force. When the speed reaches 0 and the piston remains stationary, the position of the engine crankshaft can just be at the position of the target crankshaft position ± 1 crankshaft tooth. Therefore, a target pressure value can be determined through experiments, that is, when the engine maintains the target speed, by setting different test conditions, the opening degree of the throttle valve corresponding to the intake manifold pressure value is different under different test conditions, so that the engine stops under different test conditions, and the stop crankshaft position of the engine under different test conditions is determined respectively. Finally, the intake manifold pressure value when the stop crankshaft position of the engine is the target crankshaft position ± 1 crankshaft tooth can be used as the target pressure value. Thus, after the engine cuts off fuel, when the rotation speed of the generator driving the engine remains at the target speed, after adjusting the pressure value in the intake manifold to the target pressure value, when reducing the output torque of the generator, the engine speed can be decreased so that the crankshaft position when the engine stops can be close to the target crankshaft position.

[0064] S150. During the process of reducing the output torque of the generator and the engine speed, the current output torque of the generator and the current engine speed are obtained in real time.

[0065] S160. According to the current output torque of the generator and the current engine speed, adjust the crankshaft position of the engine to the target crankshaft position.

[0066] Wherein, when the crankshaft is at the target crankshaft position when the engine stops, during the next engine start, it can ensure that the engine starts smoothly and stably, which is beneficial to improving the NVH level of the engine.

[0067] Specifically, since the engine is in a fuel cut-off state, during the process of reducing the output torque of the generator, the engine speed will decrease accordingly. During this period, the engine speed and the output torque of the generator can be obtained in real time to determine the engine crankshaft position when the output torque of the generator is 0 and the generator speed is 0, and accordingly modulate the engine speed and the output torque of the generator so that when the output torque of the generator is 0 and the generator speed is 0, the crankshaft position of the engine can be the target crankshaft position to ensure that the engine can start smoothly and stably during the next engine start.

[0068] In this embodiment, by adjusting the crankshaft position during the shutdown process, the crankshaft position can be accurately, quickly and stably adjusted to the target crankshaft position to prepare for the next engine start, so that when the engine starts next time, the smoothness and stability of the engine start can be improved, and further the NVH level of the engine can be improved.

[0069] Embodiment Two

[0070] Figure 4 It is a flowchart of a control method for the parking crankshaft position of a hybrid vehicle provided in Embodiment Two of the present invention. On the basis of the above embodiment, this embodiment provides a specific control method for the pressure value in the intake manifold. As Figure 4 shown, the method includes:

[0071] S210. When a parking instruction of the hybrid vehicle is obtained, control the output torque of the engine of the hybrid vehicle to decrease, and control the generator of the hybrid vehicle to drive the engine to rotate.

[0072] S220. When the output torque of the engine decreases to the fuel cut-off torque, control the engine to cut off fuel, and control the speed at which the generator drives the engine to rotate to be maintained at the target speed.

[0073] S230. When the engine speed is the target speed, obtain the current pressure value of the intake manifold of the engine in real time.

[0074] S240. Adjust the opening value of the throttle valve in the intake manifold according to the difference between the current pressure value and the target pressure value until the current pressure value of the intake manifold reaches the target pressure value.

[0075] Specifically, when the engine speed reaches the target speed, the engine can be driven to rotate by the generator so that the engine speed remains at the target speed. At this time, the current pressure value of the intake manifold can be obtained in real time through the pressure detection sensor; if there is a deviation between the current pressure value in the intake manifold and the target pressure value, that is, the pressure value in the intake manifold can be greater than or less than the target pressure value, then the opening value of the throttle valve in the intake manifold can be adjusted to regulate the gas flow rate entering the intake manifold, so as to achieve the purpose of adjusting the gas pressure in the intake manifold; after adjusting the gas pressure in the intake manifold, the current pressure value in the intake manifold can be obtained again. If the current pressure value still deviates from the target pressure value, the opening value of the throttle valve in the intake manifold can be adjusted again, and the current pressure value in the intake manifold can be obtained again until the current pressure value in the intake manifold is consistent with the target pressure value, it can be considered that the current pressure value in the intake manifold reaches the target pressure value, and the adjustment of the opening value of the throttle valve can be stopped.

[0076] S250. When the pressure value of the intake manifold is the target pressure value, control the output torque of the generator and the engine speed to both show a downward trend.

[0077] S260. During the process of reducing the output torque of the generator and the engine speed, obtain the current output torque of the generator and the current engine speed in real time.

[0078] S270. Adjust the crankshaft position of the engine to the target crankshaft position according to the current output torque of the generator and the current engine speed.

[0079] In this embodiment, by adjusting the opening value of the throttle valve in the intake manifold according to the pressure value in the intake manifold, when the engine speed is the target speed, the pressure value in the intake manifold can be accurately adjusted to the target pressure value, so as to prepare for accurately and quickly adjusting the crankshaft position of the engine to the target crankshaft position, so that during the next engine starting process, higher smoothness and stability can be achieved, and thus the NVH level of the engine can be improved.

[0080] Embodiment III

[0081] Figure 5 This is a flowchart of a control method for the parking crankshaft position of a hybrid vehicle provided by Embodiment III of the present invention. On the basis of the above embodiments, this embodiment provides a control method for adjusting the opening value of the throttle valve in the intake manifold according to the difference between the current pressure value and the target pressure value until the current pressure value of the intake manifold reaches the target pressure value. AsFigure 5 As shown, the method includes:

[0082] S310. When a parking instruction of a hybrid vehicle is obtained, control the output torque of the engine of the hybrid vehicle to decrease, and control the generator of the hybrid vehicle to drive the engine to rotate.

[0083] S320. When the output torque of the engine decreases to the fuel cut-off torque, control the engine to cut off fuel, and control the rotational speed of the generator driving the engine to be maintained at the target rotational speed.

[0084] S330. When the rotational speed of the engine is the target rotational speed, obtain the current pressure value of the intake manifold of the engine in real time.

[0085] S340. Obtain the target pressure value of the intake manifold and the ambient pressure value of the environment where it is located.

[0086] Wherein, the ambient pressure value of the environment where the intake manifold is located can be equivalent to the atmospheric pressure, or can also be the pressure value at the intake port of the throttle valve far from the engine obtained by a corresponding gas pressure sensor, which can be designed according to actual needs, and the embodiments of the present invention do not make specific limitations in this regard. The target pressure value in the intake manifold can be obtained through experiments. In an optional embodiment, the specific method for obtaining the target pressure value in the intake manifold can be: when the engine is undergoing a shutdown test, control the rotational speed of the motor driving the engine to be maintained at the target rotational speed; adjust the opening of the throttle valve in the intake manifold until the pressure of the intake manifold is the preset pressure; control the output torque of the generator to decrease to 0, and obtain the current rotational speed of the engine and the crankshaft position of the engine in real time; when the current rotational speed of the engine decreases to 0, determine whether the crankshaft position of the engine is the preset crankshaft position; if so, determine the preset pressure as the target pressure value.

[0087] Specifically, during the engine shutdown test, the engine can be set to the idle state, and the output torque of the generator drives the engine to rotate, so that the engine speed is maintained at the target speed. At this time, the pressure in the intake manifold can be controlled by adjusting the opening of the throttle valve in the intake manifold. When the pressure in the intake manifold reaches the preset pressure, the opening of the throttle valve can be kept unchanged, and the torque of the generator is controlled to zero. At this time, the engine speed decreases to 0 under the action of the piston reaction force, and the crankshaft position of the engine at this time is obtained, and it is judged whether this crankshaft position is the preset crankshaft position. For example, it can be the target crankshaft position - 1 crankshaft tooth, or the target crankshaft position + 1 crankshaft tooth. If this crankshaft position is the preset crankshaft position, then this preset pressure can be determined as the target pressure value. If this crankshaft position is not the preset crankshaft position, the preset pressure can be adjusted by a preset increment or decrement, so that the preset pressure increases or decreases, and then return to control the engine to be in the idle state again. The generator drags the engine to maintain at the target speed, and the opening of the throttle valve in the intake manifold is adjusted so that the pressure in the intake manifold is the adjusted preset pressure. At this preset pressure, the output torque of the generator is controlled to zero again, the engine speed drops to 0, and the crankshaft position of the engine is obtained. If this crankshaft position is the preset crankshaft position, then the adjusted preset pressure can be used as the target pressure value. If the crankshaft position of the engine still cannot reach the preset crankshaft position after adjusting the preset pressure, the preset pressure can be adjusted again until the crankshaft position of the engine reaches the preset crankshaft position.

[0088] S350. Determine the target opening value of the throttle valve in the intake manifold according to the ambient pressure value and the target pressure value.

[0089] Among them, the ambient pressure value, the target pressure value, and the target opening value of the throttle valve can satisfy a certain mapping relationship, and this mapping relationship can be a relational expression, a relationship curve, or a relationship table. In an exemplary embodiment, after determining the ambient pressure value and the target pressure value, the unique target opening value of the throttle valve can be determined by looking up a table.

[0090] S360. Control the opening value of the throttle valve in the intake manifold to be adjusted to the target opening value.

[0091] S370. Based on the PI control algorithm, adjust the opening value of the throttle valve in the intake manifold according to the difference between the current pressure value and the target pressure value until the current pressure value is the target pressure value.

[0092] Specifically, after determining the target opening value of the throttle valve according to the ambient pressure value and the target pressure value, the opening of the throttle valve can be adjusted to this target opening value to adjust the gas pressure in the intake manifold, so that the current pressure value in the intake manifold can approach the target pressure value. Although the current pressure value in the intake manifold can approach the target pressure value, it is not equal to the target pressure value, that is, there will be a certain deviation between the current pressure value and the target pressure value in the intake manifold. At this time, the difference between the current pressure value and the target pressure value can be used as the input of the PI control algorithm to determine the opening adjustment amount of the throttle valve. According to this opening adjustment amount, the opening of the throttle valve in the intake manifold is adjusted, so that the opening of the throttle valve is adjusted to the sum of the target opening value and the opening adjustment amount on the basis of the target opening value. At this time, the current pressure value in the intake manifold can be obtained again. If the current pressure in the intake manifold is the target pressure value, the deviation between the current pressure value and the target pressure value in the intake manifold is close to 0. At this time, the opening adjustment amount of the throttle valve is also 0, and the opening of the throttle valve can be kept unchanged. On the contrary, if the current pressure value still cannot reach the target pressure value after adjusting the throttle valve opening, a throttle valve opening adjustment amount can be determined again based on the PI control algorithm, and the throttle valve opening can be adjusted again until the current pressure value in the intake manifold reaches the target pressure value.

[0093] S380. When the pressure value of the intake manifold is the target pressure value, control the output torque of the generator and the engine speed to both show a downward trend.

[0094] S390. During the process of reducing the output torque of the generator and the engine speed, continuously obtain the current output torque of the generator and the current engine speed in real time.

[0095] S3100. According to the current output torque of the generator and the current engine speed, adjust the crankshaft position of the engine to the target crankshaft position.

[0096] In this embodiment, after adjusting the opening of the throttle valve to the target opening value, the current pressure value in the intake manifold can approach the target pressure value, realizing a rough adjustment of the gas pressure in the intake manifold. Then, based on the difference between the current pressure value and the target pressure value in the intake manifold, the opening of the throttle valve is adjusted based on the PI control algorithm to achieve the purpose of precisely adjusting the gas pressure in the intake manifold, so that the gas pressure in the intake manifold can be accurately adjusted to the target pressure value, preparing for accurately and quickly adjusting the crankshaft position of the engine to the target crankshaft position. Thus, during the next engine starting process, it can have higher smoothness and stability, and further improve the NVH level of the engine.

[0097] Embodiment 4

[0098] Figure 6The following is a flowchart of a control method for the parking crankshaft position of a hybrid vehicle provided in Embodiment 4 of the present invention. On the basis of the above embodiments, the method for adjusting the crankshaft position of the engine to the target crankshaft position in the embodiments of the present invention is specified. As Figure 6 shown, the method specifically includes:

[0099] S410. When a parking instruction of the hybrid vehicle is obtained, control the output torque of the engine of the hybrid vehicle to decrease, and control the generator of the hybrid vehicle to drive the engine to rotate.

[0100] S420. When the output torque of the engine decreases to the fuel cut-off torque, control the engine to cut off fuel, and control the rotation speed of the generator driving the engine to be maintained at the target speed.

[0101] S430. When the rotation speed of the engine is the target speed, adjust the pressure value of the intake manifold of the engine to the target pressure value.

[0102] S440. When the pressure value of the intake manifold is the target pressure value, control both the output torque of the generator and the rotation speed of the engine to show a downward trend.

[0103] S450. During the process of reducing the output torque of the generator and the rotation speed of the engine, real-time obtain the current output torque of the generator and the current rotation speed of the engine.

[0104] S460. Determine whether the current rotation speed of the engine is less than or equal to the first preset rotation speed; if so, execute S470.

[0105] Among them, the first preset rotation speed can be a rotation speed value close to the rotation speed of 0. Exemplarily, the first preset rotation speed is 50 rpm.

[0106] Specifically, while reducing the output torque of the generator, the rotation speed of the engine will decrease accordingly. At this time, the current output torque of the generator and the current rotation speed of the engine can be obtained in real time, and it can be determined whether the current rotation speed of the engine is less than or equal to the first preset rotation speed.

[0107] S470. Real-time obtain the current crankshaft position and the current crankshaft acceleration of the engine.

[0108] Among them, the crankshaft position can be obtained at certain time intervals, and this interval is the acquisition period of the crankshaft position. Based on the adjacent two or three obtained crankshaft positions and the acquisition period, the crankshaft acceleration can be calculated. Exemplarily, taking the acquisition period T as 10 ms as an example, the first crankshaft position S1 is obtained at the start of the first 10 ms, and the third crankshaft position S3 is obtained at the start of the third 10 ms. At this time, the crankshaft acceleration can be determined by dividing the difference between S1 and S2 by two acquisition periods, that is, the crankshaft acceleration a = (S2 - S1) / (10 ms * 2).

[0109] In an alternative embodiment, the engine is a four-stroke four-cylinder engine; the target crankshaft position can be the normalized position of the target crankshaft positions corresponding to the compression cylinders of the engine; obtaining the current crankshaft position of the engine specifically includes: obtaining the actual crankshaft positions corresponding to the compression cylinders of the engine; normalizing each actual crankshaft position, and determining the normalized crankshaft position as the current crankshaft position of the engine.

[0110] Specifically, for a four-stroke four-cylinder engine, due to the symmetry of the compression cylinders of the engine, there should be four current crankshaft positions. These four current crankshaft positions correspond to different angles within the 720-degree range of the crankshaft. However, for each compression cylinder, it corresponds to the same angle. Therefore, it is necessary to normalize the current crankshaft positions of the compression cylinders of the engine, normalize the current crankshaft positions of different compression cylinders to the current crankshaft position of the same compression cylinder, divide the actual current crankshaft position of each compression cylinder by 180 degrees, remove the integer part of the result, and multiply the remaining decimal part by 180 degrees to obtain the normalized current crankshaft position.

[0111] Correspondingly, when the obtained current crankshaft position is normalized, the same normalization method is also used for the target crankshaft position, and finally the four target crankshaft positions are normalized to one target crankshaft position. The engine speed and the output torque of the generator are controlled using the normalized current crankshaft position and the target crankshaft position.

[0112] S480. Determine the predicted crankshaft position of the engine based on the current crankshaft position and the current crankshaft acceleration.

[0113] S490. Based on the difference between the predicted crankshaft position and the target crankshaft position, adjust the output torque of the generator according to the P control algorithm until the current speed of the engine is 0 and the crankshaft position of the engine is the target crankshaft position.

[0114] Specifically, when the current engine speed is less than or equal to the first preset speed, it can be determined that the engine speed is about to be 0. At this time, the current crankshaft position and the current crankshaft acceleration of the engine can be obtained in real time. According to the current crankshaft position and the crankshaft acceleration, the crankshaft position when the engine speed is 0 can be calculated as the predicted crankshaft position. If the predicted crankshaft position is the target crankshaft position, it can be considered that reducing the engine speed in the current state can make the crankshaft position of the engine reach the target crankshaft position when the engine speed is 0; if there is a deviation between the predicted crankshaft position and the target crankshaft position, it can be determined that reducing the engine speed in the current state cannot make the crankshaft position of the engine reach the target crankshaft position when the engine speed is 0. At this time, according to the difference between the predicted crankshaft position and the target crankshaft position, based on the P control algorithm, the output torque of the generator can be adjusted, that is, the difference between the predicted crankshaft position and the target crankshaft position is used as the input of the P control algorithm, and the output torque of the generator is used as the output of the P control algorithm, and then the output torque of the generator can be determined. Based on the output torque of the generator, the operating state of the generator can be adjusted, so as to achieve the purpose of adjusting the rotation state of the engine; after adjusting the rotation state of the engine, the current crankshaft position and the current crankshaft acceleration of the engine can be obtained again, and the predicted crankshaft position can be calculated again based on the current crankshaft position and the crankshaft acceleration until the predicted crankshaft position is the target crankshaft position, so that when the engine speed is 0, the crankshaft position of the engine can reach the target crankshaft position.

[0115] In this embodiment, through the current crankshaft position and the current crankshaft acceleration of the engine, the shutdown crankshaft position of the engine is predicted as the predicted crankshaft position, and based on the difference between the predicted crankshaft position and the target crankshaft position, the output torque of the generator is adjusted based on the P control algorithm, so that the engine can stop quickly and stably at the target crankshaft position, so that in the next engine starting process, it can have higher smoothness and stability, and further improve the NVH level of the engine.

[0116] Embodiment 5

[0117] Figure 7 FIG. 10 is a schematic structural diagram of a control device 700 for the parking crankshaft position of a hybrid vehicle provided in Embodiment 5 of the present invention. This embodiment is applicable to the situation of controlling the crankshaft position of the engine when the hybrid vehicle is driving and parking. The device can be implemented in the form of hardware and / or software. The device can execute the control method for the parking crankshaft position of the hybrid vehicle provided in any embodiment of the present invention. The device can be configured in the vehicle controller of the hybrid vehicle, such as Figure 7 shown, the control device 700 for the parking crankshaft position of the hybrid vehicle includes:

[0118] The engine torque control module 701 is used to control the output torque of the engine of the hybrid vehicle to decrease when a parking instruction of the hybrid vehicle is obtained, and control the generator of the hybrid vehicle to drive the engine to rotate;

[0119] The engine speed control module 702 is used to control the engine to cut off fuel when the output torque of the engine decreases to the fuel cut-off torque, and control the speed at which the generator drives the engine to rotate to be maintained at the target speed;

[0120] The pressure adjustment module 703 is used to adjust the pressure value of the intake manifold of the engine to the target pressure value when the speed of the engine is the target speed;

[0121] The torque and speed control module 704 is used to control the output torque of the generator and the speed of the engine to both show a downward trend when the pressure value of the intake manifold is the target pressure value;

[0122] The speed acquisition module 705 is used to acquire the current output torque of the generator and the current speed of the engine in real time during the process of reducing the output torque of the generator and the speed of the engine;

[0123] The crankshaft position adjustment module 706 is used to adjust the crankshaft position of the engine to the target crankshaft position according to the current output torque of the generator and the current speed of the engine.

[0124] The technical solution of this embodiment realizes that during the parking process, the crankshaft position of the engine can be accurately and quickly controlled at the set position through the cooperation between each module, and solves the problems of low starting smoothness and low control stability during the starting process of the traditional solution.

[0125] The control device for the parking crankshaft position of the hybrid vehicle provided by the embodiment of the present invention can execute the control method for the parking crankshaft position of the hybrid vehicle provided by any embodiment of the present invention, has the corresponding functional modules and beneficial effects for executing the method, and the same parts can be referred to the above description and will not be repeated here.

[0126] Embodiment Six

[0127] This application also provides a hybrid vehicle, including: an engine, a generator, and a vehicle controller; the vehicle controller is used to execute the control method for the shutdown crankshaft position of the hybrid vehicle in any embodiment of the present invention.

[0128] The hybrid vehicle provided by the embodiment of the present invention can execute the control method for the parking crankshaft position of the hybrid vehicle provided by any embodiment of the present invention, has the corresponding functional modules and beneficial effects for executing the method, and the same parts can be referred to the above description and will not be repeated here.

[0129] Embodiment Seven

[0130] The present application also provides a computer-readable storage medium storing computer instructions for causing a processor to execute the control method for the parking crankshaft position of a hybrid vehicle provided in any embodiment of the present invention.

[0131] In the context of the present invention, a computer-readable storage medium may be a tangible medium that can contain or store a computer program for use by or in connection with an instruction execution system, apparatus, or device. The computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. Alternatively, the computer-readable storage medium may be a machine-readable signal medium. More specific examples of the machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0132] To provide for interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the electronic device. Other kinds of devices can also be used to provide for interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic, speech, or tactile input).

[0133] The systems and techniques described herein can be implemented in a computing system including a backend component (e.g., as a data server), or a computing system including a middleware component (e.g., an application server), or a computing system including a frontend component (e.g., a user computer having a graphical user interface or a web browser through which the user can interact with an implementation of the systems and techniques described herein), or a computing system including any combination of such backend, middleware, or frontend components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of the communication network include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0134] A computing system may include a client and a server. The client and the server are generally far from each other and usually interact via a communication network. The client-server relationship is created by computer programs running on respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or a cloud host, which is a host product in the cloud computing service system, and solves the defects of difficult management and weak business scalability existing in traditional physical hosts and VPS services.

[0135] It should be understood that various forms of processes shown above can be used, steps can be reordered, added or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solution of the present invention can be achieved, and no limitation is made herein.

[0136] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A control method for the parking crankshaft position of a hybrid vehicle, characterized in that, it includes: When receiving the parking instruction of the hybrid vehicle, controlling the output torque of the engine of the hybrid vehicle to decrease, and controlling the generator of the hybrid vehicle to drive the engine to rotate; When the output torque of the engine decreases to the fuel cut-off torque, controlling the engine to cut off fuel, and controlling the rotational speed of the generator driving the engine to be maintained at the target rotational speed; When the rotational speed of the engine is the target rotational speed, the current pressure value of the intake manifold of the engine is obtained in real time; Obtain the target pressure value of the intake manifold and the ambient pressure value of the environment where it is located; According to the ambient pressure value and the target pressure value, determine the target opening value of the throttle valve in the intake manifold; Control the opening value of the throttle valve in the intake manifold to be adjusted to the target opening value; According to the difference between the current pressure value and the target pressure value, based on the PI control algorithm, adjust the opening value of the throttle valve in the intake manifold until the current pressure value is the target pressure value; When the pressure value of the intake manifold is the target pressure value, control the output torque of the generator and the rotational speed of the engine to both show a downward trend; During the process of reducing the output torque of the generator and the rotational speed of the engine, the current output torque of the generator and the current rotational speed of the engine are obtained in real time; According to the current output torque of the generator and the current rotational speed of the engine, adjust the crankshaft position of the engine to the target crankshaft position.

2. The control method for the parking crankshaft position of a hybrid vehicle according to claim 1, characterized in that, obtaining the target pressure value of the intake manifold includes: When the engine conducts a shutdown test, controlling the rotational speed of the motor driving the engine to be maintained at the target rotational speed; Adjust the opening of the throttle valve in the intake manifold until the pressure of the intake manifold is the preset pressure; Control the output torque of the generator to be reduced to 0, and obtain the current rotational speed of the engine and the crankshaft position of the engine in real time; When the current rotational speed of the engine is reduced to 0, determine whether the crankshaft position of the engine is the preset crankshaft position; If so, determine the preset pressure as the target pressure value.

3. The control method for the parking crankshaft position of a hybrid vehicle according to claim 2, characterized in that, obtaining the target pressure value of the intake manifold further includes: If the crankshaft position of the engine does not reach the preset crankshaft position, adjust the preset pressure by a preset adjustment amount, and return to execute the steps of adjusting the opening of the throttle valve in the intake manifold until the pressure of the intake manifold is the preset pressure until when the current rotational speed of the engine is reduced to 0, determine whether the crankshaft position of the engine is the preset crankshaft position.

4. The control method for the parking crankshaft position of a hybrid vehicle according to claim 1, characterized in that, adjusting the crankshaft position of the engine to the target crankshaft position according to the current output torque of the generator and the current rotational speed of the engine includes: Determine whether the current speed of the engine is less than or equal to the first preset speed; If so, obtain the current crankshaft position and the current crankshaft acceleration of the engine in real time; Determine the predicted crankshaft position of the engine according to the current crankshaft position and the current crankshaft acceleration; Based on the difference between the predicted crankshaft position and the target crankshaft position, adjust the output torque of the generator based on the P control algorithm until the current speed of the engine is 0 and the crankshaft position of the engine is the target crankshaft position.

5. The control method for the parking crankshaft position of a hybrid vehicle according to claim 4, wherein, the engine is a four-stroke four-cylinder engine; the target crankshaft position is the normalized position of the target crankshaft positions corresponding to the compression cylinders of the engine; Obtaining the current crankshaft position of the engine includes: Obtain the actual crankshaft positions corresponding to the compression cylinders of the engine; Normalize each of the actual crankshaft positions, and determine the normalized crankshaft position as the current crankshaft position of the engine.

6. A control device for the parking crankshaft position of a hybrid vehicle, wherein, comprising: An engine torque control module, configured to control the output torque of the engine of the hybrid vehicle to decrease and control the generator of the hybrid vehicle to drive the engine to rotate when a parking instruction of the hybrid vehicle is obtained; An engine speed control module, configured to control the engine to cut off fuel when the output torque of the engine decreases to the fuel cut-off torque, and control the speed of the generator driving the engine to be maintained at a target speed; A pressure adjustment module, configured to obtain the current pressure value of the intake manifold of the engine in real time when the speed of the engine is the target speed; obtain the target pressure value of the intake manifold and the ambient pressure value of the environment; determine the target opening value of the throttle valve in the intake manifold according to the ambient pressure value and the target pressure value; control the opening value of the throttle valve in the intake manifold to be adjusted to the target opening value; Based on the difference between the current pressure value and the target pressure value, adjust the opening value of the throttle valve in the intake manifold based on the PI control algorithm until the current pressure value is the target pressure value; A torque and speed control module, configured to control both the output torque of the generator and the speed of the engine to show a downward trend when the pressure value of the intake manifold is the target pressure value; A speed acquisition module, configured to obtain the current output torque of the generator and the current speed of the engine in real time during the process of reducing the output torque of the generator and the speed of the engine; A crankshaft position adjustment module, configured to adjust the crankshaft position of the engine to the target crankshaft position according to the current output torque of the generator and the current speed of the engine.

7. A hybrid vehicle, wherein, comprising: An engine, a generator and a vehicle controller; The vehicle controller is configured to execute the control method for the parking crankshaft position of the hybrid vehicle according to any one of claims 1-5.

8. A computer-readable storage medium, wherein, The computer-readable storage medium stores computer instructions for causing a processor to implement the control method for the parking crankshaft position of a hybrid vehicle according to any one of claims 1-5 when executed.

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