CN112606815B

CN112606815B - Method and device for determining motor reserve torque of hybrid vehicle and vehicle

Info

Publication number: CN112606815B
Application number: CN202011418647.8A
Authority: CN
Inventors: 刘义强; 井俊超; 于雪梅; 肖逸阁; 王瑞平; 安聪慧
Original assignee: Zhejiang Geely Holding Group Co Ltd; Ningbo Geely Royal Engine Components Co Ltd; Zhejiang Geely Power Train Co Ltd
Current assignee: Aurora Bay Ningbo Intelligent Technology Co ltd; Zhejiang Geely Holding Group Co Ltd; Aurobay Technology Co Ltd
Priority date: 2020-12-07
Filing date: 2020-12-07
Publication date: 2022-08-02
Anticipated expiration: 2040-12-07
Also published as: CN112606815A

Abstract

The invention discloses a method, a device and a vehicle for determining the motor reserve torque of a hybrid vehicle. The method includes: obtaining the starting torque of the clutch based on the starting gear of the clutch; The amplification factor of the motor torque compensation corresponding to the gear; obtain the gear ratio of the motor and the gear ratio of the clutch start gear, according to the gear ratio of the motor, the gear ratio of the clutch start, and the motor torque compensation and the starting torque of the clutch to determine the motor compensation torque; based on the vehicle speed, the motor compensation torque is corrected to obtain the motor reserve torque. The invention can avoid the phenomenon that the acceleration of the vehicle is obviously attenuated due to the power loss of the clutch starting the engine, and can also avoid the phenomenon that the starting and acceleration capability of the low-speed pure electric is limited due to the excessive reserve torque.

Description

Method and device for determining motor reserve torque of hybrid vehicle and vehicle

Technical Field

The invention relates to the technical field of vehicles, in particular to a method and a device for determining motor reserve torque of a hybrid vehicle and the vehicle.

Background

With the increasingly strict requirements of national regulations on oil consumption and emission and the development of electrified systems, the hybrid power technology becomes the key for realizing energy conservation and emission reduction. In order to meet national policies and emission regulations, the entire car factory and parts suppliers are looking for solutions. However, the battery technology of the current pure electric vehicle technology system is complex, the cost is high, and the structure of the hybrid power system determines the types of the working modes which can be realized, so that the hybrid power system generally has a relatively complex structure in order to realize a plurality of working modes. This complex structure results in the hybrid system occupying a relatively large space, greatly reducing the space utilization inside the vehicle.

The P2.5 configuration single-motor hybrid system can combine the advantages of the P2 system and the P3 system, and avoid the disadvantages of the P2 system and the P3 system, and the structure is shown in FIG. 1. The P2.5 configuration hybrid system motor has three torque output paths, namely an ISG path, an Efad path and a Disengaged path. The ISG path is that the motor is connected with the engine through a C2 clutch and is disconnected with the even number shaft of the gearbox; the eFad path means that the motor is directly connected with the even number shaft gears (2, 4, 6) of the gearbox for assisting or charging, and the motor is disconnected with the engine; disengaged path means that the electric machine is disconnected from both the engine and the even numbered shafts of the gearbox. The P2.5 hybrid system has three starting modes, namely 12V starting, ISG motor starting and clutch starting. The 12V starting is mainly aimed at the low-speed working condition less than 10km/h, the starting of the 12V starter is the starting mode of the traditional vehicle, and the priority of the use of the 12V starter on the hybrid vehicle is low. ISG launch is primarily for the pivot PN gear, which is typically used for engine launch at vehicle speeds of 0 or very low, e.g., less than 10km/h, ISG output torque, clutch 2 engagement, and reverse tow engine launch. The clutch start is usually used for engine start at low, medium and high vehicle speeds, the clutch 1 or the clutch 2 is combined (depending on the starting gear) to reversely drag the engine to start through the vehicle running inertia, meanwhile, the ISG outputs torque to the wheel end to compensate, and the clutch start is divided into different start modes (mainly according to the speed of the clutch torque output), such as quick start, safe start, smooth start and the like, so as to meet different working conditions during start.

For a P2.5 configuration single-motor hybrid power system, when the vehicle is driven by a motor in pure electric driving, the clutch needs to be started when the starting condition of the clutch is met, and the clutch needs to apply torque to drag the engine to a target rotating speed, so that certain loss is caused to the driving force of the whole vehicle, a part of torque needs to be reserved by the motor to compensate the starting torque of the clutch, and therefore, a method for determining the reserved torque of the motor of the hybrid power vehicle is needed.

Disclosure of Invention

The invention aims to provide a method and a device for determining the reserve torque of a motor of a hybrid vehicle and the vehicle, which can avoid the phenomenon that the acceleration of the vehicle is obviously attenuated due to the power loss of a clutch starting engine when the clutch is started, and can avoid the phenomenon that the low-speed pure electric starting and accelerating capacity is limited due to overlarge reserve torque.

The invention is realized by the following technical scheme:

in a first aspect, the present invention provides a method for determining a reserve torque of a motor of a hybrid vehicle, comprising:

acquiring starting torque of the clutch based on the starting gear of the clutch;

determining an amplification factor of motor torque compensation corresponding to the starting gear according to the starting gear;

acquiring a gear speed ratio of a motor and a clutch starting gear speed ratio, and determining motor compensation torque according to the gear speed ratio of the motor, the clutch starting gear speed ratio, an amplification factor of motor torque compensation and starting torque of a clutch;

and correcting the motor compensation torque based on the vehicle speed to obtain the motor reserve torque.

Further, the obtaining of the starting torque of the clutch based on the starting gear of the clutch includes:

determining a target rotating speed of the engine according to the starting gear;

acquiring the actual rotating speed of an engine and the water temperature of the engine;

and determining the starting torque of the clutch according to the target rotating speed of the engine, the actual rotating speed of the engine and the water temperature of the engine.

Further, the determining, according to the starting gear, an amplification factor of the motor torque compensation corresponding to the starting gear includes:

and corresponding to the starting gear, based on the working condition that the motor torque is not limited in the starting process of the clutch under the accelerator, the amplification factor of the motor torque compensation is gradually increased from 1 until the vehicle is not subjected to pause and contusion when the clutch is started.

Further, the determining a motor compensation torque according to the gear speed ratio of the motor, the clutch starting gear speed ratio, the amplification factor of the motor torque compensation and the starting torque of the clutch includes:

multiplying the starting torque of the clutch by the amplification factor of the motor torque compensation corresponding to the starting gear, and then multiplying the speed ratio of the starting gear of the clutch to obtain the wheel end torque required by starting the clutch;

and dividing the wheel end torque by the gear speed ratio of the motor to obtain the motor compensation torque.

Further, the correcting the motor compensation torque based on the vehicle speed to obtain a motor reserve torque includes:

setting the motor reserve torque as 0 when the vehicle speed is 0, and setting the motor reserve torque as a first preset reserve torque when the vehicle speed is a first preset vehicle speed;

and obtaining vehicle speed information, and if the vehicle speed is between 0 and a first preset vehicle speed, calculating to obtain the motor reserve torque under the vehicle speed by using an interpolation method.

Further, the correcting the motor compensation torque based on the vehicle speed to obtain a motor reserve torque further includes:

and if the vehicle speed is greater than the first preset vehicle speed, determining the motor compensation torque as the motor reserve torque under the vehicle speed.

Further, the first preset vehicle speed is 15-20 km/h.

Further, the first preset reserve torque is 800 Nm.

In a second aspect, the present invention provides a hybrid vehicle motor reserve torque determination apparatus comprising:

the first obtaining module is used for obtaining starting torque of the clutch based on a starting gear of the clutch;

the first determination module is used for determining an amplification factor of motor torque compensation corresponding to the starting gear according to the starting gear;

the second determination module is used for acquiring a gear speed ratio of the motor and a clutch starting gear speed ratio, and determining a motor compensation torque according to the gear speed ratio of the motor, the clutch starting gear speed ratio, an amplification factor of the motor torque compensation and a starting torque of the clutch;

and the correction module is used for correcting the motor compensation torque based on the vehicle speed to obtain the motor reserve torque.

In a third aspect, the invention provides a vehicle comprising the above hybrid vehicle motor reserve torque determination apparatus.

The implementation of the invention has the following beneficial effects:

the invention determines the reserved torque of the motor based on the starting gear and the vehicle speed, can avoid the phenomenon that the acceleration of the vehicle is obviously attenuated due to the power loss of the clutch starting engine when the clutch is started, and can avoid the phenomenon that the low-speed pure electric starting and accelerating capacity is limited due to overlarge reserved torque.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions and advantages of the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic structural diagram of a P2.5 hybrid power system provided by an embodiment of the invention;

FIG. 2 is a test chart of an actual vehicle with a clutch activated according to an embodiment of the present invention;

FIG. 3 is a schematic flow chart diagram illustrating a method for determining a reserve torque for a motor of a hybrid vehicle according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a device for determining a reserve torque of a motor of a hybrid vehicle according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the following examples. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," "third," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in other sequences than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or server that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Examples

For a hybrid vehicle with a P2.5 configuration, during pure electric driving, a motor drives the vehicle, when a clutch starting condition is met, clutch starting is required, a test chart of the clutch starting is shown in FIG. 2, in the test chart, a represents vehicle speed, b represents engine rotating speed, 1 represents motor torque, 2 represents actual clutch starting torque, and 3 represents motor compensation torque, when a starting request exists in the pure electric driving process with the D-gear vehicle speed of more than 10kph, the clutch starting is preferentially selected, the engine is dragged to a target rotating speed through clutch sliding mode control, during the clutch starting process, the motor torque is divided into two parts, one part of the motor torque is used for driving the vehicle, the other part of the motor torque is reserved during the pure electric driving process, and the motor torque is used as compensation to ensure that the driving force of a wheel end is stable during the clutch starting process. Because the clutch is required to apply torque when the clutch is started, the towing engine is driven to the target rotating speed, and certain loss is caused to the driving force of the whole vehicle, a part of torque is required to be reserved by the motor to compensate the starting torque of the clutch so as to ensure that the acceleration of the vehicle is stable during towing, no obvious jerking or front impact is caused, and a driver of a medium-sized accelerator and a small-sized accelerator cannot easily and actively detect the starting; the quick throttle is started with the fastest response possible, and a certain degree of impact can be accepted. If the reserved torque is too large, the low-speed pure electric starting and accelerating capacity can be limited; if the reserve torque is too small, the motor compensation torque is insufficient, which can cause the acceleration of the vehicle to be obviously attenuated and generate the jerk feeling.

In order to solve the above problems, the present specification provides a technical solution for determining a reserved torque of a motor based on a starting gear and a vehicle speed; specifically, the method comprises the following steps:

embodiments of the present invention provide a method for determining a reserve torque of an electric machine of a hybrid vehicle, such as the flowchart shown in fig. 3, and the present specification provides the method steps as described in the embodiments or the flowchart, but may include more or less steps based on conventional or non-inventive labor. The order of steps recited in the embodiments is merely one manner of performing the steps in a multitude of orders and does not represent the only order of execution. In practice, the system or server product may be implemented in a sequential or parallel manner (e.g., parallel processor or multi-threaded environment) according to the embodiments or methods shown in the figures. Specifically, as shown in fig. 3, the method may include: :

and S301, acquiring the starting torque of the clutch based on the starting gear of the clutch.

In one specific embodiment, acquiring the starting torque of the clutch based on the starting gear of the clutch comprises: determining a target rotating speed of the engine according to the starting gear; acquiring the actual rotating speed of an engine and the water temperature of the engine; and determining the starting torque of the clutch according to the target rotating speed of the engine, the actual rotating speed of the engine and the water temperature of the engine.

Specifically, the clutch start torque table is a table reflecting the correspondence relationship between the start torque of the clutch and the target engine speed, the actual engine speed, and the engine water temperature, and the start torque of the clutch can be directly determined according to the table.

The method considers the influence of the water temperature of the engine on the starting target torque of the clutch, and can obtain the most appropriate starting target torque of the clutch, so that the engine is started more smoothly.

It should be noted that, when the dragging starts, a large torque is provided to the clutch, and when the dragging torque is rapidly reduced after the engine speed starts to increase until the engine speed approaches the target speed, the dragging torque is set to 0, so as to avoid interference caused by clutch torque holding after the speed is established.

And S302, determining an amplification factor of the motor torque compensation corresponding to the starting gear according to the starting gear.

A large setting of the amplification factor due to the motor torque compensation may result in a vehicle front-rush during starting, while a small setting may result in vehicle jerk. In one specific embodiment, determining the amplification factor of the motor torque compensation corresponding to the starting gear according to the starting gear comprises:

corresponding to a starting gear, the working condition that the motor torque is not limited in the starting process of the clutch under the throttle is preset as a reference, specifically, the throttle is preset as a medium-small throttle, in practical application, a person skilled in the art can set the specific opening degree of the medium-small throttle according to specific conditions and actual needs, the amplification factor of the motor torque compensation is gradually increased from 1 until the vehicle is not subjected to jerk when the clutch is started, and the amplification factor of the motor torque compensation corresponding to the starting gear can be obtained.

In this embodiment, the amplification factor of motor torque compensation is set independently for each starting gear to make the reserve torque calculation of motor more accurate, avoid the vehicle that motor reserve torque undersize leads to and feel that suddenly stops, and avoid the restriction low-speed electricelectric starting and acceleration ability that leads to because motor reserve torque is too big.

S303, acquiring a gear speed ratio of the motor and a clutch starting gear speed ratio, and determining a motor compensation torque according to the gear speed ratio of the motor, the clutch starting gear speed ratio, an amplification factor of motor torque compensation and a starting torque of the clutch;

since the clutch starting gear and the motor gear are not necessarily the same, a shift is required. In one specific embodiment, determining the motor compensation torque according to the gear speed ratio of the motor, the clutch starting gear speed ratio, the amplification factor of the motor torque compensation and the starting torque of the clutch comprises: multiplying the starting torque of the clutch by an amplification coefficient of motor torque compensation corresponding to a starting gear, and then multiplying by the speed ratio of the starting gear of the clutch to obtain the wheel end torque required by starting the clutch; the wheel end torque is divided by the gear speed ratio of the motor to obtain the motor compensation torque, namely, the calculation formula of the motor compensation torque is as follows: the motor compensation torque is (starting torque of the clutch) × (amplification factor of the motor torque compensation) × (clutch starting gear speed ratio) ÷ gear speed ratio of the motor.

And S304, correcting the motor compensation torque based on the vehicle speed to obtain a motor reserve torque.

In one specific embodiment, the motor compensation torque is corrected based on the vehicle speed to obtain the motor reserve torque, and the method comprises the following steps: setting the motor reserve torque as 0 when the vehicle speed is 0, and setting the motor reserve torque as a first preset reserve torque when the vehicle speed is a first preset vehicle speed; and obtaining the vehicle speed information, and calculating to obtain the motor reserve torque under the vehicle speed by using an interpolation method if the vehicle speed is between 0 and a first preset vehicle speed.

Specifically, the first preset vehicle speed may be 15-20 km/h, and the first preset reserve torque may be 800 Nm.

It should be noted that, in practical applications, a person skilled in the art may set the first preset reserve torque to other values according to the specific situation of the vehicle, as long as the same function as in the present embodiment can be achieved.

In one specific embodiment, the motor compensation torque is corrected based on the vehicle speed to obtain the motor reserve torque, and the method further comprises the following steps: and if the vehicle speed is greater than the first preset vehicle speed, determining the motor compensation torque as the motor reserve torque under the vehicle speed. Specifically, at high vehicle speeds, the required torque reserve will be gradually reduced since the starting gear is higher, corresponding to a smaller gear ratio.

Generally, the reserve torque of the motor needs to be ensured to match the clutch torque compensated during starting, but too large limits the purely dynamic performance, and too small easily causes jerk during starting. According to the existing system configuration, the lowest gear of clutch activation is gear 2, corresponding to a speed ratio of 9.65, which is multiplied by the maximum drag torque to obtain the minimum torque reserve under ideal conditions. However, this results in a large torque reserve for the low-speed electric machine, which significantly limits the low-speed electric-only launch and acceleration capabilities of the hybrid vehicle. Thus, in this embodiment, a tradeoff is made for reserve torque at low speeds, i.e., the smoothness of partial clutch launch is sacrificed to improve the dynamics of the electric-only operating condition, and the reserve torque setting of the electric machine is based on wheel-end torque and is related to vehicle speed. In the embodiment, the vehicle speed 0 is set to be 0 so as to ensure pure electric dynamic property; the first preset vehicle speed is set to 800Nm which is the minimum setting under the premise of ensuring basic starting smoothness and considering pure electric power; for vehicle speeds between 0 and a first preset vehicle speed, for example a reserve torque setting at 8km/h, an interpolation linearization is used in order to improve the linearity of the purely electrical acceleration; at high vehicle speeds, the required torque reserve is gradually reduced, since the starting gear is higher and the corresponding transmission ratio is smaller.

According to the technical scheme provided by the embodiment of the specification, the motor reserve torque is determined based on the starting gear and the vehicle speed, when the clutch is started, the phenomenon that the acceleration of the vehicle is obviously attenuated due to the power loss of the clutch starting engine can be avoided, and the phenomenon that the low-speed pure electric starting and accelerating capacity is limited due to overlarge reserve torque can be avoided. In addition, when the vehicle speed is zero, the reserved torque of the motor is set to be zero, and pure electric dynamic performance at low speed can be guaranteed.

An embodiment of the present invention further provides a device for determining a reserved torque of a motor of a hybrid vehicle, and referring to fig. 4, the device includes: the first obtaining module is used for obtaining starting torque of the clutch based on a starting gear of the clutch; the first determination module is used for determining an amplification factor of motor torque compensation corresponding to a starting gear according to the starting gear; the second determination module is used for acquiring the gear speed ratio of the motor and the clutch starting gear speed ratio, and determining the motor compensation torque according to the gear speed ratio of the motor, the clutch starting gear speed ratio, the amplification factor of the motor torque compensation and the starting torque of the clutch; and the correction module is used for correcting the motor compensation torque based on the vehicle speed to obtain the motor reserve torque.

It should be noted that the device and method embodiments in the device embodiment are based on the same inventive concept. For details, please refer to the method embodiment, which is not described herein.

The device for determining the motor reserve torque of the hybrid vehicle in the embodiment of the invention determines the motor reserve torque based on the starting gear and the vehicle speed, can avoid the phenomenon that the acceleration of the vehicle is obviously attenuated due to the power loss of the clutch starting engine when the clutch is started, and can avoid the phenomenon that the low-speed pure electric starting and accelerating capacity is limited due to overlarge reserve torque.

The embodiment of the invention also provides a vehicle which comprises the device for determining the reserve torque of the motor of the hybrid vehicle. Due to the technical effects of the device for determining the reserved torque of the motor of the hybrid vehicle, the vehicle in the embodiment should also have the same technical effects, and the details are not repeated herein.

The above embodiment of the invention has the following beneficial effects: the invention determines the reserved torque of the motor based on the starting gear and the vehicle speed, can avoid the phenomenon that the acceleration of the vehicle is obviously attenuated due to the power loss of the clutch starting engine when the clutch is started, and can avoid the phenomenon that the low-speed pure electric starting and accelerating capacity is limited due to overlarge reserved torque.

It should be noted that: the precedence order of the above embodiments of the present invention is only for description, and does not represent the merits of the embodiments. And specific embodiments of the present invention have been described above. Other embodiments are within the scope of the following claims. In some cases, the actions or steps recited in the claims may be performed in a different order than in the embodiments and still achieve desirable results.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the device and vehicle embodiments, since they are substantially similar to the method embodiments, the description is relatively simple, and reference may be made to some descriptions of the method embodiments for relevant points.

Finally, it should be noted that: while the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims

1. A method of determining a reserve torque for an electric motor of a hybrid vehicle, comprising:

correcting the motor compensation torque based on the vehicle speed to obtain a motor reserve torque; the correcting the motor compensation torque based on the vehicle speed to obtain the motor reserve torque comprises the following steps: setting the motor reserve torque as 0 when the vehicle speed is 0, and setting the motor reserve torque as a first preset reserve torque when the vehicle speed is a first preset vehicle speed; obtaining vehicle speed information, and calculating to obtain motor reserve torque under the vehicle speed by using an interpolation method if the vehicle speed is between 0 and a first preset vehicle speed; and if the vehicle speed is greater than the first preset vehicle speed, determining the motor compensation torque as the motor reserve torque under the vehicle speed.

2. The method for determining the reserved torque of the motor of the hybrid vehicle according to claim 1, wherein the obtaining the starting torque of the clutch based on the starting gear of the clutch comprises:

3. The method of determining a reserved torque for a motor of a hybrid vehicle according to claim 1, wherein determining the amplification factor of the motor torque compensation corresponding to the starting gear according to the starting gear comprises:

4. The method of determining a reserve torque of an electric machine of a hybrid vehicle of claim 1, wherein determining a motor compensation torque based on a gear speed ratio of the electric machine, a clutch launch gear speed ratio, an amplification factor of the motor torque compensation, and a launch torque of the clutch comprises:

5. The method for determining the reserve torque of the motor of the hybrid vehicle according to claim 1, wherein the first preset vehicle speed is 15-20 km/h.

6. The method of determining a reserve torque of a motor of a hybrid vehicle according to claim 5, wherein the first preset reserve torque is 800 Nm.

7. A hybrid vehicle motor reserve torque determination apparatus, comprising:

the first determining module is used for determining an amplification factor of motor torque compensation corresponding to the starting gear according to the starting gear;

the second determination module is used for acquiring a gear speed ratio of a motor and a clutch starting gear speed ratio, and determining a motor compensation torque according to the gear speed ratio of the motor, the clutch starting gear speed ratio, an amplification factor of the motor torque compensation and a starting torque of the clutch;

the correction module is used for correcting the motor compensation torque based on the vehicle speed to obtain motor reserve torque; the method for correcting the motor compensation torque based on the vehicle speed to obtain the motor reserve torque comprises the following steps: the motor reserve torque is set to be 0 when the vehicle speed is 0, and is set to be first preset reserve torque when the vehicle speed is first preset vehicle speed; obtaining vehicle speed information, and calculating to obtain motor reserve torque under the vehicle speed by using an interpolation method if the vehicle speed is between 0 and a first preset vehicle speed; and if the vehicle speed is greater than the first preset vehicle speed, determining the motor compensation torque as the motor reserve torque under the vehicle speed.

8. A vehicle characterized by comprising the hybrid vehicle motor reserve torque determining apparatus of claim 7.