Engine rotating speed control method and device for extended-range hybrid vehicle

Abstract

The invention discloses an engine rotating speed control method and device for an extended-range hybrid vehicle, and the method comprises the steps: obtaining the rechargeable power of a battery pack in the vehicle, and taking a part of the rechargeable power of the battery pack as reserved basic power; the heating power of a heating film of the battery pack is obtained, and the reserved power is determined according to the reserved basic power and the heating power; and after the accelerator is loosened under the high-power driving working condition, the engine is requested to reduce the torque, and the generator generates negative torque through reserved power, so that the rotating speed of the engine is reduced. The problem that in the prior art, under the working condition that the charging and discharging power of a battery pack is extremely low, the accelerator loosening range extender flies at a high rotating speed after a driver drives with a large accelerator is solved.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to an engine speed control method and device for an extended-range hybrid vehicle. Background Art

[0002] When the charging and discharging power of the battery pack is low, and to ensure the normal driving of the vehicle, the HCU will request the range extender to start. When the driver steps deeply on the accelerator to drive at high power, the range extender will generate high power to provide driving power to the drive motor to meet the driver's needs. When the range extender continues to generate high power, the driver suddenly releases the accelerator to coast, and the HCU software will quickly reduce the torque request to the drive motor and request the range extender to reduce power. The range extender reduces power by reducing the torque request to the engine and reducing the speed request to the generator. Due to the torque characteristics of the engine, the engine torque cannot follow the request value well. At the same time, because the charging power of the battery is extremely small, the generator does not have the negative power generation capacity to control the engine speed. This results in the engine speed being too high under high-power driving conditions with extremely small charging power of the battery pack. Summary of the invention

[0003] In view of this, an object of the present invention is to provide an engine speed control method and device for an extended-range hybrid vehicle, aiming to solve the problem in the prior art that the engine speed is too high under high-power driving conditions with extremely low battery pack charging power.

[0004] An object of the present invention is to provide an engine speed control method for an extended-range hybrid vehicle, the method comprising: Obtain the rechargeable power of the battery pack in the vehicle, and use part of the rechargeable power of the battery pack as the reserved basic power; Acquire the heating power of the heating film of the battery pack, and determine the reserved power according to the reserved basic power and the heating power; After releasing the accelerator in a high-power driving condition, the engine is requested to reduce torque, and the generator is made to generate negative torque through the reserved power to reduce the engine speed.

[0005] Furthermore, in the above-mentioned engine speed control method for the extended-range hybrid vehicle, the step of obtaining the heating power of the heating film of the battery pack comprises: Determine whether the heating film is in working state; If yes, the current heating power of the heating film is used as the heating power; If not, the heating power is determined to be zero.

[0006] Furthermore, in the above-mentioned method for controlling the engine speed of the extended-range hybrid vehicle, the step of requesting the engine to reduce the torque comprises: The engine is requested to perform torque reduction and the engine is requested to respond quickly to the torque request through a torque fast reduction flag signal, so that the actual torque at the flywheel end of the engine quickly catches up with the torque request value of the torque request.

[0007] Furthermore, in the above-mentioned engine speed control method of the extended-range hybrid vehicle, the triggering logic of the torque fast-drop flag signal is to recognize that the vehicle has triggered the TipOut flag when the battery pack is at low charging power, wherein the condition for triggering the TipOut flag is that the accelerator pedal opening value drops by more than a certain slope within a certain period of time.

[0008] Furthermore, in the above-mentioned method for controlling the engine speed of the extended-range hybrid vehicle, after the step of using the reserved power to make the generator generate negative torque and thereby reduce the engine speed, the method further comprises: The actual speed of the engine is obtained in real time. When the actual speed is higher than the speed threshold and lasts for a preset time, the engine is requested to perform a fuel cut-off process through the fuel cut-off flag.

[0009] Another object of the present invention is to provide an engine speed control device for an extended-range hybrid vehicle, characterized in that the device comprises: An acquisition module is used to acquire the rechargeable power of the battery pack in the vehicle and use part of the rechargeable power of the battery pack as the reserved basic power; A determination module, used to obtain the heating power of the heating film of the battery pack, and determine the reserved power according to the reserved basic power and the heating power; The control module is used to request the engine to reduce torque after the accelerator is released in a high-power driving condition, and to use the reserved power to make the generator generate negative torque to reduce the engine speed.

[0010] Another object of the present invention is to provide an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the program.

[0011] The present invention obtains the rechargeable power of the battery pack in the vehicle and uses part of the rechargeable power of the battery pack as the reserved basic power; obtains the heating power of the heating film of the battery pack and determines the reserved power according to the reserved basic power and the heating power; after releasing the accelerator in high-power driving conditions, requests the engine to reduce torque, and uses the reserved power to make the generator generate negative torque to reduce the engine speed, and controls the engine speed under the joint action of the reserved power to make the generator generate negative torque to reduce the engine speed, and the engine torque is quickly reduced. The problem of the engine speed flying under high-power driving conditions with extremely small battery pack charging power in the prior art is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a flow chart of the engine speed control method of the extended-range hybrid vehicle in the first embodiment of the present invention; Figure 2 1 is a structural block diagram of an engine speed control device for an extended-range hybrid vehicle in a third embodiment of the present invention.

[0013] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0014] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0015] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0017] Embodiment 1 See also Figure 1 , which shows an engine speed control method for a range-extended hybrid vehicle in a first embodiment of the present invention, and the method includes steps S10 to S12.

[0018] Step S10, obtaining the rechargeable power of the battery pack in the vehicle, and using part of the rechargeable power of the battery pack as the reserved basic power.

[0019] For the problem of the range extender speed flying after the driver releases the accelerator after driving at high throttle under conditions where the battery pack charging and discharging power is extremely low. When the range extender is generating power at high power, the problem of the range extender speed flying after the driver releases the accelerator after driving at high throttle under conditions where the battery pack charging and discharging power is extremely low can be appropriately optimized by reserving the rechargeable power of the battery pack. For example: the rechargeable power of the battery pack is 15kw, and when the HCU (hybrid controller) software controls the range extender to generate power, the maximum charging power of the battery pack is 10kw, and the remaining 5kw is reserved for power. To ensure that the battery pack will not overcharge the battery pack charging current under normal driving conditions, the HCU's dynamic control of the range extender and drive motor and the dynamic response of the controlled components cannot ensure that the controlled components respond completely to the request status of the HCU. The 5kw power generation power reservation can optimize the problem of instantaneous battery overcharging caused by dynamic control response problems. When the range extender is driving at high power, after releasing the accelerator, the drive motor consumes 0 power, the battery rechargeable power is extremely low, and the engine torque drop response characteristics are slow. The reserved 5kw power can be used for the generator power generation capacity to reduce the speed of the range extender. The reserved power of this part cannot be set too large. If the reserved power is too large, the normal power generation power of the range extender will be less than the rechargeable power of the battery pack, which may cause the battery pack to be unable to operate effectively during driving.

[0020] Step S11, obtaining the heating power of the heating film of the battery pack, and determining the reserved power according to the reserved basic power and the heating power.

[0021] Among them, the control strategy technology that reserves the rechargeable power of the battery pack to optimize the range extender's flying speed cannot fundamentally solve the range extender's flying speed problem. The reservation of the rechargeable power of the battery pack can only be used when the driver releases the accelerator to reduce the power of the drive motor, and the generator in the range extender can pull down the engine speed through the reserved power. Because the power reserve value cannot be set too large, and the torque capacity given to the generator through the reserved power will decrease as the speed of the generator increases, the generator's ability to pull down the engine speed through the reserved power is limited at the moment the accelerator is released. When the range extender generates high power and the speed is high, the reserved power has no obvious effect on the optimization of the flying speed.

[0022] Therefore, the power reserve is increased to ensure the engine speed suppression effect after the power reserve is increased. Specifically, the reserved basic power can be added with the heating power of the battery pack's heating film as the new reserved power. Based on the working current of the heating film when the heating film is working, it is reflected in the current CAN signal of the battery pack, so the battery pack heating film power can be added as part of the reserved power. Conversely, when the heating film is not working, the reserved power cannot consider the heating film power. Taking into account the volatility of the heating film heating power and the overcharge performance of the battery, the power reserve is a certain amount of the rated power of the battery pack heating film.

[0023] Step S12, after releasing the accelerator in a high-power driving condition, requesting the engine to reduce the torque, and using the reserved power to make the generator generate negative torque to reduce the engine speed.

[0024] After releasing the accelerator in high-power driving conditions, the engine speed is requested to decrease, and the generator generates negative torque through reserved power, thereby reducing the engine speed. At the same time, the engine torque is requested to decrease and the engine is requested to respond quickly to the torque request through the torque fast-drop flag signal, and the real torque at the engine flywheel end quickly keeps up with the torque request value. The triggering logic of the engine torque fast-drop flag is that when the battery pack is at low charging power, after recognizing that the vehicle has triggered the TipOut flag, it will request the engine to enter the torque fast-drop logic. Under the joint action of the reserved power and the engine torque fast-drop logic, the engine speed is controlled.

[0025] In summary, the present invention obtains the rechargeable power of the battery pack in the vehicle and uses part of the rechargeable power of the battery pack as the reserved basic power; obtains the heating power of the heating film of the battery pack and determines the reserved power according to the reserved basic power and the heating power; after releasing the accelerator in high-power driving conditions, requests the engine to reduce torque, and uses the reserved power to make the generator generate negative torque to reduce the engine speed, and controls the engine speed under the joint action of the reserved power to make the generator generate negative torque to reduce the engine speed, and the engine torque is quickly reduced. This solves the problem in the prior art that the engine speed is high under high-power driving conditions with extremely small battery pack charging power.

[0026] Embodiment 2 This embodiment also provides an engine speed control method for an extended-range hybrid vehicle. The engine speed control method for the extended-range hybrid vehicle in this embodiment is different from the engine speed control method for the extended-range hybrid vehicle in the first embodiment in that: After the step of using the reserved power to make the generator generate negative torque and thus reduce the engine speed, the following step is further performed: The actual speed of the engine is obtained in real time. When the actual speed is higher than the speed threshold and lasts for a preset time, the engine is requested to perform a fuel cut-off process through the fuel cut-off flag.

[0027] Among them, if under the joint action of the reserved power and the engine torque fast reduction logic, the dynamic control engine based on the range extender still has a slight overspeed phenomenon (the actual speed of the range extender is higher than the target speed by a certain value and lasts for a certain period of time), after identifying this working condition, the engine will be requested to cut off the fuel through the fuel cut-off flag. The actual torque drop speed of the engine after executing the fuel cut-off request is faster than the torque reduction speed triggered by the fast drop flag. Specifically, the fuel cut-off flag means that when the engine receives the fuel cut-off flag request, the EMS software will stop injecting fuel into the cylinder combustion chamber. Because there are no atomized gasoline particles inside the cylinder, it cannot ignite and output torque. At this time, the engine's execution torque will drop rapidly.

[0028] In summary, the engine speed control method of the extended-range hybrid vehicle in the above embodiment of the present invention obtains the rechargeable power of the battery pack in the vehicle and uses part of the rechargeable power of the battery pack as the reserved basic power; obtains the heating power of the heating film of the battery pack and determines the reserved power according to the reserved basic power and the heating power; after releasing the accelerator in high-power driving conditions, requests the engine to reduce torque, and uses the reserved power to make the generator generate negative torque to reduce the engine speed, and controls the engine speed under the joint action of the reserved power to make the generator generate negative torque to reduce the engine speed, and the engine torque is quickly reduced. This solves the problem of the engine speed being too high in the high-power driving condition with extremely small battery pack charging power in the prior art.

[0029] In addition, the present invention has at least the following beneficial effects: 1. Increase the power reserve in the existing control technology without affecting the power of the vehicle, and optimize the range extender's flying speed from the source as much as possible; 2. At the moment of releasing the accelerator, the HCU software recognizes that the vehicle has entered the TipOut state, and the HCU software sets the engine execution torque fast reduction flag signal to request the engine torque to quickly execute the requested torque; 3. Based on the above two control points, if the range extender has a slight flying speed, the HCU will request the engine to cut off the fuel supply after identifying the working condition. After the engine executes the fuel cut-off logic, the actual torque drop speed is faster than the torque reduction speed triggered by the fast drop flag.

[0030] Embodiment 3 See also Figure 2 , which shows an engine speed control device for a range-extended hybrid vehicle proposed in a third embodiment of the present invention, the device comprises: An acquisition module 100 is used to acquire the rechargeable power of the battery pack in the vehicle and use part of the rechargeable power of the battery pack as the reserved basic power; A determination module 200, configured to obtain a heating power of a heating film of the battery pack, and determine a reserved power according to the reserved basic power and the heating power; The control module 300 is used to request the engine to reduce torque after the accelerator is released in a high-power driving condition, and to use the reserved power to make the generator generate negative torque to reduce the engine speed.

[0031] Furthermore, in the above-mentioned engine speed control device for the extended-range hybrid vehicle, the step of obtaining the heating power of the heating film of the battery pack comprises: Determine whether the heating film is in working state; If yes, the current heating power of the heating film is used as the heating power; If not, the heating power is determined to be zero.

[0032] Furthermore, in the above-mentioned engine speed control device for the extended-range hybrid vehicle, the step of requesting the engine to reduce torque comprises: The engine is requested to perform torque reduction and the engine is requested to respond quickly to the torque request through a torque fast reduction flag signal, so that the actual torque at the flywheel end of the engine quickly catches up with the torque request value of the torque request.

[0033] Furthermore, in the engine speed control device of the above-mentioned extended-range hybrid vehicle, the triggering logic of the torque fast-drop flag signal is to recognize that the vehicle has triggered the TipOut flag when the battery pack is at low charging power, wherein the condition for triggering the TipOut flag is that the accelerator pedal opening value drops by more than a certain slope within a certain period of time.

[0034] Furthermore, in the above-mentioned engine speed control device for the extended-range hybrid vehicle, after the step of using the reserved power to make the generator generate negative torque and thereby reduce the engine speed, the step further includes: The actual speed of the engine is obtained in real time. When the actual speed is higher than the speed threshold and lasts for a preset time, the engine is requested to perform a fuel cut-off process through the fuel cut-off flag.

[0035] The functions or operation steps implemented when the above modules are executed are substantially the same as those in the above device embodiments, and will not be described in detail here.

[0036] Embodiment 4 Another aspect of the present invention further provides a readable storage medium having a computer program stored thereon, and when the program is executed by a processor, the steps of the method described in any one of the above embodiments 1 to 2 are implemented.

[0037] Embodiment 5 Another aspect of the present invention provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method described in any one of the above-mentioned embodiments one to two when executing the program.

[0038] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0039] Those skilled in the art will appreciate that the logic and / or steps represented in the flowchart or otherwise described herein, for example, may be considered as an ordered list of executable instructions for implementing logical functions, and may be specifically implemented in any computer-readable storage medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For purposes of this specification, a "computer-readable storage medium" may be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0040] More specific examples (a non-exhaustive list) of computer-readable storage media include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable storage medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0041] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or a combination thereof: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0042] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0043] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for controlling engine speed of a range-extended hybrid vehicle, characterized in that: The method comprises: Obtain the rechargeable power of the battery pack in the vehicle, and use part of the rechargeable power of the battery pack as the reserved basic power; Acquire the heating power of the heating film of the battery pack, and determine the reserved power according to the reserved basic power and the heating power; After releasing the accelerator in a high-power driving condition, the engine is requested to reduce torque, and the generator is made to generate negative torque through the reserved power to reduce the engine speed.

2. The engine speed control method of the extended-range hybrid vehicle according to claim 1, characterized in that: The step of obtaining the heating power of the heating film of the battery pack comprises: Determine whether the heating film is in working state; If yes, the current heating power of the heating film is used as the heating power; If not, the heating power is determined to be zero.

3. The engine speed control method of the extended-range hybrid vehicle according to claim 2, characterized in that: The step of requesting the engine to perform torque reduction comprises: The engine is requested to perform torque reduction and the engine is requested to respond quickly to the torque request through a torque fast reduction flag signal, so that the actual torque at the flywheel end of the engine quickly catches up with the torque request value of the torque request.

4. The engine speed control method of the extended-range hybrid vehicle according to claim 3, characterized in that: The triggering logic of the torque fast drop flag signal is to recognize that the vehicle has triggered the TipOut flag when the battery pack is at low charging power. The condition for triggering the TipOut flag is that the accelerator pedal opening value drops by more than a certain slope within a certain period of time.

5. The engine speed control method of the extended-range hybrid vehicle according to claim 4, characterized in that: After the step of using the reserved power to make the generator generate negative torque and thus reduce the engine speed, the following step is further performed: The actual speed of the engine is obtained in real time. When the actual speed is higher than the speed threshold and lasts for a preset time, the engine is requested to perform a fuel cut-off process through the fuel cut-off flag.

6. An engine speed control device for a range-extended hybrid vehicle, characterized in that: The device comprises: An acquisition module is used to acquire the rechargeable power of the battery pack in the vehicle and use part of the rechargeable power of the battery pack as the reserved basic power; A determination module, used to obtain the heating power of the heating film of the battery pack, and determine the reserved power according to the reserved basic power and the heating power; The control module is used to request the engine to reduce torque after the accelerator is released in a high-power driving condition, and to use the reserved power to make the generator generate negative torque to reduce the engine speed.

7. A storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

8. An electronic device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method according to any one of claims 1 to 5 when executing the program.

Images