Control method and system for a hydrodynamic torque converter of a continuously variable transmission

Abstract

The application discloses a control method and system for a hydraulic torque converter of a continuously variable transmission, and comprises an activation stage and a cooperative control stage. In the activation stage, the running state information of the automobile is acquired, and it is judged whether the running state information satisfies the preset activation condition. If it is judged that the running state information satisfies the activation condition, the cooperative control stage is entered. In the cooperative control stage, the transmission state information and the engine torque information are acquired, and the torque of the engine and the speed ratio of the transmission are cooperatively controlled according to the transmission state information and the engine torque information. Through the method, after the rotating speed crossing condition is identified, the torque of the engine and the speed ratio of the transmission are cooperatively controlled in combination with the torque transmission characteristic of the hydraulic torque converter, so that the rotating speed crossing process is timely and stably powered, and the driving performance is improved.

Description

Technical Field

[0001] This invention relates to the field of automotive transmission system technology, and in particular to a control method and system for a hydraulic torque converter for a continuously variable transmission (CVT). Background Technology

[0002] like Figure 1 As shown, in a continuously variable transmission (CVT) with a torque converter, when coasting at low speeds, the engine speed drops below the turbine speed, and the torque converter is in a reverse-dragging state. When the accelerator is pressed, the torque converter can only start transmitting torque when the engine speed rises above the turbine speed. If the engine and transmission are not properly controlled at this time, and the speed ratio changes too quickly, the turbine speed will rise too fast, and the engine speed will not be able to catch up in time, resulting in sluggish power response. In addition, if the engine torque rises too quickly, the torque converter's operating state will change rapidly from reverse-dragging to traction, causing a rapid change in the direction of torque transmission in the powertrain. Due to factors such as transmission system clearances, this can easily cause a relatively noticeable impact on the entire vehicle.

[0003] Therefore, the existing control methods for hydraulic torque converters used in continuously variable transmissions suffer from poor driving performance. Summary of the Invention

[0004] The purpose of this invention is to solve the problem of poor driving performance in the control methods of hydraulic torque converters for continuously variable transmissions in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides a control method for a hydraulic torque converter for a continuously variable transmission, comprising the following steps:

[0006] Activation phase: Acquire the vehicle's operating status information, determine whether the operating status information meets the preset activation conditions, and if the operating status information meets the activation conditions, then enter the collaborative control phase;

[0007] Cooperative control phase: Acquire transmission status information and engine torque information, and perform torque reduction control on the engine and gearbox ratio cooperative control based on the transmission status information and engine torque information.

[0008] By adopting the above technical solution, the control method for the continuously variable transmission (CVT) torque converter provided in this embodiment, after identifying the speed-crossing condition, combines the torque transmission characteristics of the torque converter to achieve timely and smooth speed-crossing through the coordinated control of engine torque and transmission speed ratio, thereby improving driving performance.

[0009] Furthermore, another embodiment of the present invention provides a control method for a hydraulic torque converter for a continuously variable transmission (CVT). In the activation phase, the operating status information includes TCU (Transmission Control Unit) fault information, vehicle speed information, throttle opening information, turbine speed and engine speed difference information, hydraulic torque converter status information, gear information, braking information, and speed travel process information.

[0010] The activation conditions include: no TCU fault code, vehicle speed within the first speed threshold range, throttle within the first opening threshold range, the difference between the turbine speed and the engine speed within the first threshold range, the torque converter being in the open state, gear being in D or S mode, speed crossing not exceeding the time limit, and brakes not being activated.

[0011] Using the above technical solution, this embodiment determines whether the activation conditions are met during the activation phase by judging TCU fault information, vehicle speed information, throttle opening information, turbine speed and engine speed difference information, torque converter status information, gear information, braking information, and speed travel process information. If the activation conditions are met, speed ratio control is performed on the torque converter. This method can further improve control accuracy.

[0012] Furthermore, another embodiment of the present invention provides a control method for a hydraulic torque converter for a continuously variable transmission (CVT), wherein the transmission state information includes pass-through information;

[0013] During the uncrossed speed phase, the engine output torque is controlled in real time based on the throttle opening information, and the turbine speed is kept constant.

[0014] During the speed transition phase, a torque limiting request is sent to the engine, and the increase in the engine torque limiting value per cycle is calculated based on the throttle opening information, the difference between the turbine speed and the engine speed, and the rate of change of the difference information, so as to determine the final torque limiting value of the engine.

[0015] After the speed crossover, the actual torque of the engine is obtained, and the current torque of the engine and the current speed of the turbine are controlled according to the actual torque and the difference between the turbine speed and the engine speed.

[0016] By adopting the above technical solution, this embodiment can further improve control accuracy by implementing different control methods in three stages.

[0017] Furthermore, another embodiment of the present invention provides a control method for a hydraulic torque converter for a continuously variable transmission (CVT).

[0018] After the speed crossover, if it is determined that the difference between the turbine speed and the engine speed exceeds the first threshold range, the torque converter is controlled to exit the speed ratio control.

[0019] If it is determined that the final torque limit value is greater than the actual torque, the engine exits torque limit control.

[0020] Furthermore, another embodiment of the present invention provides a control system for a continuously variable transmission (CVT) torque converter, including an information detection module and a control module; the control module is communicatively connected to the information detection module, the transmission, and the engine, respectively; wherein,

[0021] The information detection module is used to detect vehicle operating status information, transmission status information, and engine torque information. The control module acquires the operating status information and the engine torque information, and compares the operating status information with pre-stored activation condition information to determine whether the operating status information meets the activation conditions of the collaborative control strategy. If so, the control module performs torque reduction control on the engine and speed ratio collaborative control on the transmission based on the transmission status information and engine torque information.

[0022] Furthermore, another embodiment of the present invention provides a control system for a hydraulic torque converter for a continuously variable transmission (CVT), wherein the operating status information includes transmission controller fault information, vehicle speed information, throttle opening information, turbine speed and engine speed difference information, hydraulic torque converter status information, gear information, braking information, and speed travel process information.

[0023] Furthermore, another embodiment of the present invention provides a control system for a hydraulic torque converter for a continuously variable transmission (CVT), wherein the transmission state information includes pass-through information; wherein,

[0024] During the initial stage before the engine speed crosses the threshold, the control module controls the engine's output torque in real time based on the throttle opening information and keeps the turbine speed constant.

[0025] During the speed transition phase, the control module sends a torque limiting request to the engine and calculates the increase in the engine torque limiting value for each cycle based on the throttle opening information, the difference between the turbine speed and the engine speed, and the rate of change of the difference information, in order to determine the final torque limiting value of the engine.

[0026] After the speed crossover, the control module obtains the actual torque of the engine, and controls the current torque of the engine and the current speed of the turbine based on the actual torque and the difference between the turbine speed and the engine speed.

[0027] Furthermore, another embodiment of the present invention provides a control system for a hydraulic torque converter for a continuously variable transmission (CVT).

[0028] After the speed crossover, if the control module determines that the difference between the turbine speed and the engine speed is greater than the first threshold range, the control module controls the transmission to exit the speed ratio coordination control.

[0029] If the control module determines that the final torque limit value is greater than the actual torque, the control module controls the engine to exit torque limit control.

[0030] Furthermore, another embodiment of the present invention provides a control system for a continuously variable transmission (CVT) torque converter, wherein the control system further includes a counting module, and the counting module is connected to the control module via signal communication; wherein,

[0031] When the accelerator pedal of the car is pressed, the control module controls the counting module to start counting and acquires the counting result in real time;

[0032] After the crossing is completed, the control module controls the counting module to stop counting.

[0033] Furthermore, another embodiment of the present invention provides a control system for a hydraulic torque converter for a continuously variable transmission (CVT), wherein the control module includes a transmission controller and an engine controller, the information detection module includes a sensor, and the counting module includes a counter.

[0034] Other features and corresponding beneficial effects of the present invention will be described in the latter part of the specification, and it should be understood that at least some of the beneficial effects will become obvious from the description in the specification. Attached Figure Description

[0035] Figure 1 A partial schematic diagram of an automotive transmission system equipped with a hydraulic torque converter;

[0036] Figure 2 A flowchart of the control method for a hydraulic torque converter for a continuously variable transmission provided in Embodiment 1 of the present invention;

[0037] Figure 3 Performance curves of the control method for the continuously variable transmission hydraulic torque converter provided in Embodiment 1 of the present invention, without implementation;

[0038] Figure 4 Performance curves of the control method for the continuously variable transmission hydraulic torque converter provided in Embodiment 1 of the present invention;

[0039] Figure 5This is a schematic diagram of the control system for a continuously variable transmission (CVT) hydraulic torque converter provided in Embodiment 2 of the present invention.

[0040] Explanation of reference numerals in the attached figures:

[0041] 10. Control module;

[0042] 20. Information Detection Module;

[0043] 30. Transmission;

[0044] 40. Engine. Detailed Implementation

[0045] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to this embodiment. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0046] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0047] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to this embodiment. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0049] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0050] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of the invention is usually placed in during use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0051] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0052] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0053] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0054] Example 1:

[0055] This embodiment provides a control method for a hydraulic torque converter used in a continuously variable transmission, comprising the following steps:

[0056] Activation phase: Acquire the vehicle's operating status information, determine whether the operating status information meets the preset activation conditions, and if the operating status information meets the activation conditions, then enter the collaborative control phase.

[0057] Cooperative control phase: Acquire transmission status information and engine torque information, and perform cooperative control of engine torque and transmission speed ratio based on transmission status information and engine torque information.

[0058] Specifically, the control method for the continuously variable transmission (CVT) torque converter provided in this embodiment, after identifying the speed-crossing condition, combines the torque transmission characteristics of the torque converter to achieve a timely and smooth speed-crossing process through the coordinated control of engine torque and transmission speed ratio, thereby improving driving performance.

[0059] More specifically, in this embodiment, speed ratio control is used to control the speed ratio of the continuously variable transmission (CVT), thereby controlling the output turbine speed of the hydraulic torque converter.

[0060] Furthermore, another embodiment of this invention provides a control method for a continuously variable transmission (CVT) torque converter. During the activation phase, the operating status information includes TCU (Transmission Control Unit) fault information, vehicle speed information, throttle opening information, turbine speed and engine speed difference information, torque converter status information, gear information, braking information, and speed travel process information.

[0061] Activation conditions include: no TCU fault codes, vehicle speed within the first speed threshold range, throttle within the first opening threshold range, the difference between turbine speed and engine speed within the first threshold range, torque converter in the open state, gear in D or S mode, speed crossing not exceeding the time limit, and brakes not activated.

[0062] Specifically, in this implementation, during the activation phase, the system determines whether the activation conditions are met by analyzing TCU fault information, vehicle speed information, throttle opening information, turbine speed vs. engine speed difference information, torque converter status information, gear information, braking information, and speed travel process information. If the activation conditions are met, the continuously variable transmission (CVT) speed ratios are controlled in a coordinated manner. This method can further improve control accuracy.

[0063] More specifically, in this embodiment, the first speed threshold range is 10km / h-60km / h.

[0064] Furthermore, another embodiment of this invention provides a control method for a hydraulic torque converter for a continuously variable transmission (CVT), wherein the transmission state information includes pass-through information.

[0065] Specifically, when the engine speed is in the uncrossed phase, the engine output torque is controlled in real time based on the throttle opening information, and the turbine speed is kept constant.

[0066] During the speed transition phase, a torque limiting request is sent to the engine, and the increase in engine torque limiting value for each cycle is calculated based on throttle opening information, the difference between turbine speed and engine speed and the rate of change of the difference information, so as to determine the final torque limiting value of the engine.

[0067] After the engine speed crossover, the actual torque of the engine is obtained, and the current torque of the engine and the current speed of the turbine are controlled based on the actual torque and the difference between the turbine speed and the engine speed.

[0068] More specifically, this implementation method can further improve control accuracy by implementing different control methods in three stages.

[0069] More specifically, in this embodiment, the final torque limit value is obtained by summing the increase in torque limit value for each cycle.

[0070] Furthermore, another embodiment of this invention provides a control method for a hydraulic torque converter for a continuously variable transmission (CVT).

[0071] After the speed crossover, if it is determined that the difference between the turbine speed and the engine speed exceeds the first threshold range, the continuously variable transmission is controlled to exit the speed ratio coordination control.

[0072] If the final torque limit value is determined to be greater than the actual torque, the engine will exit torque limiting control.

[0073] The control method for the continuously variable transmission (CVT) hydraulic torque converter provided in this embodiment is as follows: Figure 2 As shown, it includes the following steps:

[0074] S1. Obtain the vehicle's operating status information and determine whether the vehicle's operating status meets the activation conditions based on the operating status information.

[0075] If yes, proceed to step S2; if no, continue with step S1.

[0076] S2, obtain transmission status information and determine whether the transmission speed is in a crossover state;

[0077] If yes, proceed to step S3; if no, proceed to step S4.

[0078] S3. Determine whether the transmission speed is in the speed crossover phase;

[0079] If yes, proceed to step S5; if no, proceed to step S6.

[0080] S4. Control the engine's output torque in real time based on throttle opening information, and keep the turbine speed constant;

[0081] S5. Send a torque limiting request to the engine, and calculate the increase in engine torque limiting value for each cycle based on throttle opening information, turbine speed and engine speed difference information and the rate of change of the difference information, so as to determine the final torque limiting value of the engine.

[0082] S6. Obtain the actual torque of the engine, and control the current torque of the engine and the current speed of the turbine based on the actual torque and the difference between the turbine speed and the engine speed.

[0083] The control method for the continuously variable transmission (CVT) hydraulic torque converter provided in this embodiment can achieve the following effects:

[0084] For example, Figure 3 The graph shows the control method for a hydraulic torque converter used in a continuously variable transmission (CVT) that does not employ this method. Figure 4 The graph shows the control method for the hydraulic torque converter used in this continuously variable transmission (CVT). It is clear that after using this control method, the vehicle acceleration, engine torque, engine speed, and turbine speed are all more stable at any given moment. Therefore, the control method for the hydraulic torque converter provided in this embodiment can achieve timely and smooth speed transitions, thus improving driving performance.

[0085] Example 2:

[0086] This embodiment provides a control system for a hydraulic torque converter for a continuously variable transmission, such as... Figure 5 As shown, it includes an information detection module 20 and a control module 10; the control module 10 is communicatively connected to the information detection module 20, the transmission 30 and the engine 40 respectively.

[0087] Specifically, the information detection module 20 is used to detect vehicle operating status information, transmission status information and engine torque information. The control module 10 acquires the operating status information and engine torque information, and compares the operating status information with the pre-stored activation condition information to determine whether the operating status information meets the conditions of the collaborative control strategy. If so, the control module 10 performs speed ratio collaborative control on the continuously variable transmission based on the transmission status information and engine torque information.

[0088] Furthermore, another embodiment of this invention provides a control system for a continuously variable transmission (CVT) torque converter, the operating status information of which includes transmission controller fault information, vehicle speed information, throttle opening information, turbine speed and engine speed difference information, torque converter status information, gear information, braking information, and speed travel process information.

[0089] Furthermore, another embodiment of this invention provides a control system for a hydraulic torque converter for a continuously variable transmission (CVT), wherein the transmission status information includes pass-through information.

[0090] Specifically, during the non-crossing speed phase, the control module 10 controls the engine's output torque in real time based on the throttle opening information and keeps the turbine speed constant. During the crossing speed phase, the control module 10 sends a torque limiting request to the engine and calculates the increase in the engine's torque limiting value for each cycle based on the throttle opening information, the difference between the turbine speed and the engine speed, and the rate of change of the difference information, to determine the engine's final torque limiting value. After the speed crossing, the control module 10 obtains the engine's actual torque and controls the engine's current torque and the turbine's current speed based on the actual torque and the difference between the turbine speed and the engine speed.

[0091] Furthermore, another embodiment of this invention provides a control system for a continuously variable transmission (CVT) hydraulic torque converter.

[0092] After the speed crossover, if the control module 10 determines that the difference between the turbine speed and the engine speed is greater than the first threshold range, the control module 10 controls the hydraulic torque converter to exit the speed ratio control; if the control module 10 determines that the final torque limit value is greater than the actual torque, the control module 10 controls the engine to exit the torque limit control.

[0093] Furthermore, another embodiment of this invention provides a control system for a continuously variable transmission (CVT) hydraulic torque converter. The control system for the CVT hydraulic torque converter further includes a counting module, which is connected to the control module 10 via signal communication.

[0094] Specifically, when the accelerator pedal of the car is pressed, the control module 10 controls the counting module to start counting and obtains the counting result in real time; after the crossing is completed, the control module 10 controls the counting module to stop counting.

[0095] Furthermore, another embodiment of this invention provides a control system for a continuously variable transmission (CVT) hydraulic torque converter. The control module 10 includes a transmission controller and an engine controller, the information detection module 20 includes sensors, and the counting module includes a counter.

[0096] It should be understood that the models of the transmission controller, engine controller, and counter are similar to those of existing systems, and will not be listed individually in this embodiment. Of course, they can be selected according to actual needs, and this embodiment does not impose specific limitations on them.

[0097] While the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the invention to these descriptions. Various changes in form and detail can be made by those skilled in the art, including several simple deductions or substitutions, without departing from the spirit and scope of the invention.

Claims

1. A control method for a hydraulic torque converter used in a continuously variable transmission (CVT), characterized in that, Includes the following steps: Activation phase: Acquire the vehicle's operating status information, determine whether the operating status information meets the preset activation conditions, and if the operating status information meets the activation conditions, then enter the collaborative control phase; Cooperative control phase: Acquire transmission status information and engine torque information, and perform torque reduction control on the engine and speed ratio cooperative control on the transmission based on the transmission status information and engine torque information, thereby realizing the control of the turbine speed at the output end of the hydraulic torque converter; During the activation phase, the operating status information includes TCU fault information, vehicle speed information, throttle opening information, turbine speed and engine speed difference information, torque converter status information, gear information, braking information, and speed travel process information. The activation conditions include: no TCU fault code, vehicle speed within the first speed threshold range, throttle within the first opening threshold range, the difference between the turbine speed and the engine speed within the first threshold range, the torque converter being in the open state, gear being in D or S mode, speed crossing not exceeding the time limit, and brakes not being activated. The transmission status information includes crossing information; During the uncrossed speed phase, the engine output torque is controlled in real time based on the throttle opening information, and the turbine speed is kept constant. During the speed transition phase, a torque limiting request is sent to the engine, and the increase in the engine torque limiting value per cycle is calculated based on the throttle opening information, the difference between the turbine speed and the engine speed, and the rate of change of the difference information, so as to determine the final torque limiting value of the engine. After the speed crossover, the actual torque of the engine is obtained, and the current torque of the engine and the current speed of the turbine are controlled according to the actual torque and the difference between the turbine speed and the engine speed.

2. The control method for a hydraulic torque converter for a continuously variable transmission as described in claim 1, characterized in that, After the speed crossover, if it is determined that the difference between the turbine speed and the engine speed does not exceed the first threshold range, the hydraulic torque converter is controlled to perform speed ratio coordinated control. If it is determined that the final torque limit value is less than or equal to the actual torque, the engine is controlled to perform torque limiting control.

3. A control system for a hydraulic torque converter used in a continuously variable transmission (CVT), characterized in that, It includes an information detection module and a control module; the control module is communicatively connected to the information detection module, the transmission, and the engine, respectively; wherein, The information detection module is used to detect vehicle operating status information, transmission status information, and engine torque information. The control module acquires the operating status information and the engine torque information, and compares the operating status information with pre-stored activation condition information to determine whether the operating status information meets the activation conditions of the collaborative control strategy. If so, the control module performs torque reduction control on the engine and speed ratio collaborative control on the transmission based on the transmission status information and engine torque information, thereby realizing the control of the turbine speed at the output end of the hydraulic torque converter. The operating status information includes transmission controller fault information, vehicle speed information, throttle opening information, turbine speed and engine speed difference information, torque converter status information, gear information, braking information, and speed travel process information. The transmission status information includes traversal information; wherein... During the initial stage before the engine speed crosses the threshold, the control module controls the engine's output torque in real time based on the throttle opening information and keeps the turbine speed constant. During the speed transition phase, the control module sends a torque limiting request to the engine and calculates the increase in the engine torque limiting value for each cycle based on the throttle opening information, the difference between the turbine speed and the engine speed, and the rate of change of the difference information, in order to determine the final torque limiting value of the engine. After the speed crossover, the control module obtains the actual torque of the engine, and controls the current torque of the engine and the current speed of the turbine based on the actual torque and the difference between the turbine speed and the engine speed.

4. The control system for the continuously variable transmission (CVT) torque converter as described in claim 3, characterized in that, After the speed crossover, if the control module determines that the difference between the turbine speed and the engine speed does not exceed the first threshold range, the control module controls the transmission to perform speed ratio coordinated control. If the control module determines that the final torque limit value is less than or equal to the actual torque, the control module controls the engine to perform torque limiting control.

5. The control system for a continuously variable transmission (CVT) hydraulic torque converter as described in claim 3 or 4, characterized in that, The control system of the continuously variable transmission (CVT) hydraulic torque converter further includes a counting module, which is connected to the control module via signal communication. When the accelerator pedal of the car is pressed, the control module controls the counting module to start counting and acquires the counting result in real time; After the crossing is completed, the control module controls the counting module to stop counting.

6. The control system for the continuously variable transmission (CVT) hydraulic torque converter as described in claim 5, characterized in that, The control module includes a transmission controller and an engine controller, the information detection module includes sensors, and the counting module includes a counter.

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