Power dividing type hybrid power system and working method thereof

Abstract

The invention discloses a power dividing type hybrid power system which comprises a first planetary gear mechanism, a second planetary gear mechanism, a third planetary gear mechanism and a fourth planetary gear mechanism. The second planetary gear mechanism comprises a second planet carrier, a second sun gear and a second gear ring, and outer teeth of the second gear ring are meshed with outer teeth of the first gear ring; the output end of the engine is in transmission connection with the first planet carrier; the output end of the first motor is in transmission connection with the first sun gear; the output end of the second motor is in transmission connection with the second sun gear; the brake is used for controlling locking or releasing of the first gear ring and the second gear ring; the clutch is used for controlling combination or separation between the second sun gear and the second planet carrier; the transmission mechanism is in transmission connection with the second planet carrier and is used for transmitting power to wheels; the invention further discloses a working method of the power split type hybrid power system. The system is simple in structure, and comprehensive economy and dynamic property of the vehicle can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of hybrid electric vehicles, and in particular to a power split hybrid electric system and a working method thereof. Background Art

[0002] A power-split hybrid system is a system that distributes power by diverting the power output of the engine to the wheels and generators through a planetary gear set. This system achieves power diversion and convergence through a single or multiple planetary gears, and adjusts the working state of the engine and motor with more freedom, thus having better power and economy. It is one of the most efficient hybrid system methods currently. However, the current power-split hybrid system generally needs to be equipped with multiple clutches and / or brakes, as well as a transmission structure to achieve multiple working modes of the hybrid system, so as to ensure the adaptability of the vehicle in various driving conditions; at the same time, in order to meet the dynamic requirements such as climbing performance, it is necessary to select a motor with a higher power level, or to set up an additional torque-increasing structure; these inevitably make the overall structure of the hybrid system more complex, less compact, and less efficient, which is not conducive to the control of vehicle manufacturing costs.

[0003] Therefore, it is particularly necessary to study and improve the existing power-split hybrid system, hoping to ensure that the vehicle has better adaptability to driving conditions through a relatively simple structure, while at the same time being able to help improve the vehicle's power and economy. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a power-split hybrid power system and a working method thereof. The power-split hybrid power system has a simple structure and can ensure that the vehicle has good adaptability to driving conditions, which is beneficial to improving the power and economy of the vehicle.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a power-split hybrid power system, comprising: a first planetary gear mechanism, comprising a first planetary carrier, a first sun gear and a first ring gear with internal and external teeth; a second planetary gear mechanism, comprising a second planetary carrier, a second sun gear and a second ring gear with internal and external teeth, the external teeth of the second ring gear meshing with the external teeth of the first ring gear; an engine, the output end of the engine being transmission-connected to the first planetary carrier; a first motor, the output end of the first motor being transmission-connected to the first sun gear; a second motor, the output end of the second motor being transmission-connected to the second sun gear; a brake, used to manipulate the locking or releasing of the first ring gear and the second ring gear; a clutch, used to manipulate the engagement or separation between the second sun gear and the second planetary carrier; a transmission mechanism, the input end of the transmission mechanism being transmission-connected to the second planetary carrier and used to transmit power to the wheels.

[0006] Furthermore, the first motor has a first output shaft, and the first output shaft is collinear with the rotation axis of the first sun gear; the second motor has a second output shaft, and the second output shaft is collinear with the rotation axis of the second sun gear.

[0007] Furthermore, the first motor is arranged at the rear side of the first planetary gear mechanism, the first sun gear is fixedly connected to the first output shaft, the first planet carrier is provided with a first input shaft, and the output end of the engine is drivingly connected to the first input shaft.

[0008] Furthermore, the second motor is arranged at the rear side of the second planetary gear mechanism, and the second sun gear is fixedly connected to the second output shaft.

[0009] Furthermore, the output shaft of the engine is coaxially arranged with the first planet carrier.

[0010] Furthermore, the input end of the clutch is fixedly connected to the second sun gear, the output end of the clutch is connected to the second planet carrier; and the brake is connected to the first ring gear.

[0011] A working method of a power-split hybrid system is based on the power-split hybrid system described above, including a pure electric working mode, and in the pure electric working mode: the brake is engaged, the clutch is disengaged, the battery is discharged to the second motor, and the second motor is in an electric state.

[0012] Furthermore, it also includes an extended-range mode, and in the extended-range mode: the brake is engaged, the clutch is disengaged, the engine works and outputs power to the first motor, the first motor is in a power generation state, the first motor transmits electrical energy to the second motor and the battery, and the second motor is in an electric state.

[0013] Furthermore, it also includes a hybrid mode, and in the hybrid mode: the brake is disengaged, the clutch is engaged, the engine is working, the first motor is in a generating or electric state, and the second motor is in a generating or electric state; the output power of the engine and the first motor is coupled in the first planetary mechanism and transmitted to the second ring gear through the first ring gear; the output power of the second motor is coupled with the output power of the engine and the first motor in the second planetary mechanism, and finally output through the second planetary carrier.

[0014] Furthermore, it also includes a parking mode, and in the parking mode: the brake is engaged, the clutch is engaged, and the engine can selectively drive the first motor to generate electricity for parking.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The power-split hybrid power system provided by the present invention can realize multi-mode operation of the vehicle through only one brake, one clutch and a dual planetary gear mechanism. The overall structure is simple, which is conducive to improving the compactness of the vehicle layout and reducing the production and manufacturing cost of the vehicle. At the same time, there are fewer meshing parts in the system, which is conducive to improving the power transmission efficiency; at the same time, the power level requirement for the motor can be reduced, which is conducive to vehicle cost control; multiple operating modes can ensure that the vehicle has good power and economy under various driving conditions such as low and high speeds, thereby helping to improve the comprehensive economy and power of the vehicle; the working method of the power-split hybrid power system provided by the present invention is easy to control, which is conducive to improving the comprehensive economy and power of the vehicle.

[0017] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of the present invention

[0019] Figure markings: 1-first planetary gear mechanism; 101-first planetary carrier; 101a-first input shaft; 102-first sun gear; 103-first ring gear; 2-second planetary gear mechanism; 201-second planetary carrier; 202-second sun gear; 203-second ring gear; 3-engine; 4-first motor; 401-first output shaft; 5-second motor; 501-second output shaft; 6-brake; 7-clutch; 8-torsional vibration damper; 9-transmission gear; 10-differential. DETAILED DESCRIPTION

[0020] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only used to illustrate the basic concept of the present invention, and the following embodiments and the features in the embodiments can be combined with each other without conflict.

[0021] See also Figure 1In this embodiment, a power split hybrid system is disclosed, including: a first planetary gear mechanism 1, including a first planet carrier 101, a first sun gear 102 and a first ring gear 103 with internal teeth and external teeth. It can be understood that the first planetary gear mechanism 1 here also includes a first planetary gear that is simultaneously meshed with the first sun gear 102 and the inner teeth of the first ring gear 103. The first planetary gear is usually evenly distributed along the circumference of the first sun gear 102. A second planetary gear mechanism 2 includes a second planet carrier 201, a second sun gear 202 and a first ring gear 103 with internal teeth and external teeth. The second gear ring 203 with inner teeth and outer teeth, the outer teeth of the second gear ring 203 mesh with the outer teeth of the first gear ring 103. It can be understood that the second planetary gear mechanism 2 also includes a second planetary gear meshed between the second sun gear 202 and the second inner gear ring 203. The second planetary gear is generally evenly distributed along the circumference of the second sun gear 202 and is arranged in a plurality of ways; an engine 3, the output end of the engine 3 is transmission-connected to the first planet carrier 101; a first motor 4, the output end of the first motor 4 is transmission-connected to the first sun gear 102; a second motor 5, the The output end of the second motor 5 is connected to the second sun gear 202 in a transmission manner; the brake 6 is used to control the locking or releasing of the first gear ring 103 and the second gear ring 203. It can be understood that since the outer teeth of the second gear ring 203 are meshed with the outer teeth of the first gear ring 103, only one of the first gear ring 103 and the second gear ring 203 needs to be controlled to complete the rotation control of the two; the clutch 7 is used to control the combination or separation between the second sun gear 202 and the second planetary carrier 201; the transmission mechanism, the input end of the transmission mechanism is connected to the second planetary carrier 201 in a transmission manner and is used to transmit power to the wheels. Here, the transmission mechanism is generally a shaft-tooth transmission structure, such as using a transmission gear 9 connected to the second planetary carrier 201, the transmission gear 9 transmits power to the differential 10, and then transmits it to the wheels by the half shaft. Different layout designs can be adopted according to the layout requirements of the whole vehicle; of course, it can be understood that the power split hybrid system also includes a battery, a motor driver, etc. The battery is electrically connected to the motor driver, the first motor 4 and the second motor 5. This part is the same as the existing dual-motor hybrid system and will not be repeated here;

[0022] The power-split hybrid system in the above structure can realize multi-mode operation of the vehicle through only one brake 6, one clutch 7 and a dual planetary gear mechanism. The overall structure is simple, which is conducive to improving the compactness of the vehicle layout and reducing the production and manufacturing cost of the vehicle. At the same time, there are fewer meshing parts in the system, which is conducive to improving the power transmission efficiency. At the same time, the power level requirement for the motor can be reduced, which is conducive to vehicle cost control (specifically: here, since the power of the second motor 5 can be output after deceleration and torque increase by the second planetary gear mechanism 2, thereby meeting the power requirements of climbing performance and acceleration performance on flat roads, at high speeds, the power of the second motor 5 can be directly output by the second planetary carrier 201 to ensure high-speed driving requirements. The second motor 5 can use a motor with a smaller peak torque to reduce dependence on the motor); multiple operating modes (see below for details) can ensure that the vehicle has good power and economy under various driving conditions such as low and high speeds, thereby helping to improve the comprehensive economy and power of the vehicle.

[0023] In this embodiment, the first motor 4 has a first output shaft 401, and the first output shaft 401 is colinear with the rotation axis of the first sun gear 102; the second motor 5 has a second output shaft 501, and the second output shaft 501 is colinear with the rotation axis of the second sun gear 202; by arranging the first output shaft 401 of the first motor 4 and the second output shaft 501 of the second motor 5 coaxially with the first sun gear 102 and the second sun gear 202 respectively, it is conducive to forming a good adaptation with the first planetary gear mechanism 1 and the second planetary gear mechanism 2 arranged side by side, thereby further improving the overall compactness of the system and reducing the occupation of the vehicle layout space; at the same time, it is conducive to realizing the direct connection between the first output shaft 401 and the first sun gear 102, and the direct connection between the second output shaft 501 and the second sun gear 202, thereby shortening the transmission chain, further improving the transmission efficiency, reducing power waste, and further improving the comprehensive economic performance of the vehicle.

[0024] In this embodiment, the first motor 4 is arranged at the rear side of the first planetary gear mechanism 1, the first sun gear 102 is fixedly connected to the first output shaft 401, the first planetary carrier 101 is provided with a first input shaft 101a, and the output end of the engine 3 is drivingly connected to the first input shaft 101a; it should be noted that the first sun gear 102 is fixedly connected to the first output shaft 401, the first planetary carrier 101 is provided with a first input shaft 101a, and the output end of the engine 3 is drivingly connected to the first input shaft 101a; Figure 1The right end of the first planetary gear mechanism 1 is its rear side, that is, the side away from the engine 3 is the rear side; specifically, the first sun gear 102 and the first output shaft 401 are relatively fixedly connected through a spline structure; the first input shaft 101a and the first planet carrier 101 adopt an integrated structure; the output shaft of the engine 3 is connected to the first input shaft 101a after passing through the torsional vibration damper 8, and can be connected to the first input shaft 101a through a coupling, a spline connection, etc.; this arrangement structure is conducive to the arrangement and installation of the first motor 4 and the first planetary gear mechanism 1, and is conducive to the arrangement and installation of the engine 3 and the first planet carrier 101. Through a reasonable layout, it is conducive to further improving the compactness of the entire system, further shortening the transmission chain of the entire system, reducing the meshing parts, reducing power waste, and further improving the comprehensive economic performance of the vehicle.

[0025] In this embodiment, the second motor 5 is arranged at the rear side of the second planetary gear mechanism 2, and the second sun gear 202 is fixedly connected to the second output shaft 501; Figure 1 The right end of the second planetary gear mechanism 2 is its rear side, that is, the side away from the engine 3 is the rear side; specifically, the second sun gear 202 and the second output shaft 501 are relatively fixedly connected through a spline structure; this arrangement structure has a reasonable structure, a short transmission chain, reduces meshing parts, reduces power waste, and further improves the comprehensive economic performance of the vehicle; at the same time, the second motor 5 is arranged at the rear side of the second planetary gear mechanism 2, and the second planetary carrier 201 can output power to the transmission mechanism to the front side, so that it can be suitable for the arrangement on the front-engine front-wheel drive vehicle model, such as here the transmission mechanism includes a transmission gear 9 fixedly connected to the front end of the second planetary carrier 201, the transmission gear 9 is connected to the differential 10, the differential 10 is connected to the half shaft, and finally the power is transmitted to the wheel through the half shaft.

[0026] In this embodiment, the output shaft of the engine 3 is coaxially arranged with the first planetary carrier 101, that is, the axis of the output shaft of the engine 3 is colinear with the rotation centerline of the first planetary carrier 101; this is beneficial to further improve the structural compactness of the overall arrangement, shorten the transmission chain between the engine 3 and the first planetary carrier 101, reduce power waste, and further improve the comprehensive economic performance of the vehicle.

[0027] In this embodiment, the input end of the clutch 7 is fixedly connected to the second sun gear 202, and the output end of the clutch 7 is connected to the second planetary carrier 201. Specifically, the clutch 7 adopts a multi-plate wet clutch, the active part of the clutch, that is, the input end of the clutch 7 is arranged on the second sun gear 202, and the driven part of the clutch 7 is arranged on the second planetary carrier 201. The second sun gear 202 and the second planetary carrier 201 are connected or separated by controlling the connection or separation of the active part and the driven part of the clutch; the brake 6 is connected to the first ring gear 103, and the brake 6 can adopt a disc brake. The brake disc of the brake 6 is fixed on the first ring gear 103, and the brake caliper part of the brake 6 is arranged on the frame or other fixed structure. The brake caliper clamps the brake disc through the brake pad to achieve braking; it can be understood that since the outer teeth of the second ring gear 203 are meshed with the outer teeth of the first ring gear 103, the first ring gear 203 can be braked while the first ring gear 103 is braked; with this structural design, the clutch 7 and the brake 6 are arranged in a reasonable position and have good compactness.

[0028] The present embodiment also discloses a working method of a power-split hybrid power system, which is based on the power-split hybrid power system described above and includes a pure electric working mode, and in the pure electric working mode: the brake 6 is engaged, the clutch 7 is disengaged, the battery is discharged to the second motor 5, and the second motor 5 is in an electric state; in this mode, it can meet the use of working conditions such as urban congested roads, low-speed driving, and frequent braking, thereby ensuring the power economy in this mode; at the same time, in this mode, the power of the second motor 5 is decelerated and torque-increased by the second planetary gear mechanism 2, and then directly output to the transmission mechanism by the second planetary carrier 201, and then transmitted to the wheels, which can meet the use requirements of climbing performance and starting acceleration, and can improve the power of the pure electric mode; at the same time, the engagement of the brake 6 can prevent power from being transmitted to the first planetary mechanism, thereby avoiding large weak magnetic losses in the first motor 4.

[0029] In this embodiment, an extended-range mode is also included, and in the extended-range mode: the brake 6 is engaged, the clutch 7 is disengaged, the engine 3 works and outputs power to the first motor 4, the first motor 4 is in a power generation state, the first motor 4 transmits electrical energy to the second motor 5 and the battery, and the second motor 5 is in an electric state; in this mode, the first ring gear 103 and the second ring gear 203 are both locked, the second motor 5 directly drives the second sun gear 202 to rotate, and the power is transmitted to the second planetary carrier 201 to obtain a deceleration torque increase, and then the power is transmitted to the wheels by the output mechanism; in this mode, when the battery is insufficient, the engine 3 can work to supplement the power supply to ensure the long-distance driving needs of the vehicle.

[0030] In this embodiment, a hybrid mode is also included, and in the hybrid mode: the brake 6 is disengaged, the clutch 7 is engaged, the engine 3 is working, the first motor 4 is in a power generation or electric state, and the second motor 5 is in a power generation or electric state; the output power of the engine 3 and the first motor 4 is coupled in the first planetary mechanism 1, and is transmitted to the second ring gear 203 through the first ring gear 103; the output power of the second motor 5 is coupled with the output power of the engine 3 and the first motor 4 in the second planetary mechanism 2, and is finally output through the second planetary carrier 201; in this mode, according to the output power demand of the vehicle, the engine 3, the first motor 4, the second motor 5 and the first planetary mechanism are used to generate the power of the vehicle. The coordinated work of the second motor 5 and the first motor 4 ensures that the engine is always in a high-efficiency working range. The principle of coordinated regulation here is the same as that of the existing single-row planetary gear power split system, that is, the engine is always in a high-efficiency working range by adjusting the torque of the second motor 5 and the speed of the first motor 4, which will not be repeated here; thereby, the fuel economy in the hybrid mode is ensured, and the comprehensive power and economy of the whole vehicle are improved; and because the second motor 5 does not decelerate through the second planetary gear mechanism 2 at this time, but directly drives the wheels to travel, it is suitable for the high-speed cruising mode of the vehicle, and the engine 3 can have better fuel economy, which is beneficial to reduce the use of batteries and increase battery life, thereby improving the comprehensive economy of the whole vehicle.

[0031] In this embodiment, a parking mode is also included, and in the parking mode: the brake 6 is engaged, the clutch 7 is engaged, and the engine 3 can selectively drive the first motor to generate power for parking; in this mode, the vehicle is stationary, and according to the power reserve, the engine 3 can be started to complete charging, or the engine 3 can be not started to charge, and only the parking function is realized; it can also be applied to a plug-in hybrid system, and an external charging pile is used for charging; in this mode, due to the engagement of the clutch 7, braking energy recovery can also be better realized. If the car is in a non-emergency braking situation, the vehicle speed is higher than a certain limit value, and the required torque at this time is less than the maximum braking torque that the second motor 5 can provide, the braking force is all provided by the second motor 5, and the mechanical energy is converted into electrical energy and stored in the battery; if the car is in a non-emergency braking situation, the vehicle speed is higher than a certain limit value, and the required torque at this time is greater than the maximum braking torque that the second motor 5 can provide, a part of the braking force is provided by the second motor 5, and the mechanical energy is converted into electrical energy and stored in the battery, and the other part of the braking force is provided by traditional mechanical braking.

[0032] The combined use of the above modes effectively improves the comprehensive economy and power of the vehicle.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A power split hybrid system, characterized in that: include: A first planetary gear mechanism (1) comprises a first planet carrier (101), a first sun gear (102) and a first ring gear (103) having internal teeth and external teeth; A second planetary gear mechanism (2) comprises a second planet carrier (201), a second sun gear (202) and a second ring gear (203) having internal teeth and external teeth, wherein the external teeth of the second ring gear (203) mesh with the external teeth of the first ring gear (103); An engine (3), wherein an output end of the engine (3) is drivingly connected to the first planet carrier (101); A first motor (4), wherein an output end of the first motor (4) is drivingly connected to a first sun gear (102); A second motor (5), wherein an output end of the second motor (5) is drivingly connected to a second sun gear (202); A brake (6) for operating the locking or releasing of the first gear ring (103) and the second gear ring (203); A clutch (7) for controlling the engagement or separation between the second sun gear (202) and the second planet carrier (201); A transmission mechanism, wherein an input end of the transmission mechanism is transmission-connected to the second planet carrier (201) and is used to transmit power to wheels.

2. The power split hybrid system according to claim 1, characterized in that: The first motor (4) has a first output shaft (401), and the first output shaft (401) is collinear with the rotation axis of the first sun gear (102); the second motor (5) has a second output shaft (501), and the second output shaft (501) is collinear with the rotation axis of the second sun gear (202).

3. The power split hybrid system according to claim 2, characterized in that: The first motor (4) is arranged at the rear side of the first planetary gear mechanism (1), the first sun gear (102) is fixedly connected to the first output shaft (401), the first planet carrier (101) is provided with a first input shaft (101a), and the output end of the engine (3) is drivingly connected to the first input shaft (101a).

4. The power split hybrid system according to claim 2 or 3, characterized in that: The second motor (5) is arranged at the rear side of the second planetary gear mechanism (2), and the second sun gear (202) is fixedly connected to the second output shaft (501).

5. The power split hybrid system according to any one of claims 1 to 4, characterized in that: The output shaft of the engine (3) is coaxially arranged with the first planet carrier (101).

6. The power split hybrid system according to any one of claims 1 to 5, characterized in that: The input end of the clutch (7) is fixedly connected to the second sun gear (202), and the output end of the clutch (7) is connected to the second planet carrier (201); the brake (6) is connected to the first ring gear (103).

7. A method for operating a power-split hybrid power system, based on the power-split hybrid power system according to any one of claims 1 to 6, characterized in that: It includes a pure electric working mode, and in the pure electric working mode: the brake (6) is engaged, the clutch (7) is disengaged, the battery is discharged to the second motor (5), and the second motor (5) is in an electric state.

8. The operating method of the power split hybrid system according to claim 7, characterized in that: It also includes extended range mode, and in extended range mode: The brake (6) is engaged, the clutch (7) is disengaged, the engine (3) operates and outputs power to the first motor (4), the first motor (4) is in a power generation state, the first motor (4) transmits electrical energy to the second motor (5) and the battery, and the second motor (5) is in an electric state.

9. The operating method of the power split hybrid system according to claim 7 or 8, characterized in that: It also includes hybrid mode, and in hybrid mode: The brake (6) is disengaged, the clutch (7) is engaged, the engine (3) is working, the first motor (4) is in a power generation or motoring state, and the second motor (5) is in a power generation or motoring state; the output power of the engine (3) and the first motor (4) is coupled in the first planetary mechanism (1), and is transmitted to the second ring gear (203) through the first ring gear (103); the output power of the second motor (5) is coupled with the output power of the engine (3) and the first motor (4) in the second planetary mechanism (2), and is finally output through the second planetary carrier (201).

10. The working method of the power split hybrid system according to any one of claims 7 to 9, characterized in that: Also includes parking mode, and in parking mode: The brake (6) is engaged, the clutch (7) is engaged, and at the same time the engine (3) can selectively drive the first motor to generate power while parking.

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