Clutch control system and method

Abstract

This application discloses a clutch control method and system for a motor vehicle engine. The rotating shaft of the motor vehicle engine is connected to the transmission via a clutch, which can be controlled to switch between a disengaged state, a slipping state, and an engaged state. The method includes: dividing the engine speed during the motor vehicle start-up process into three speed ranges: a low-speed start-up range, a medium-speed start-up range, and a high-speed start-up range; pre-planning different engine speed control paths for each of the three speed ranges; after the motor vehicle starts, measuring the rotational speed of the engine shaft, selecting one of the planned engine speed control paths based on the measured speed range of the engine shaft, and controlling the engine speed; while controlling the engine speed, controlling the clutch to change from the disengaged state to the slipping state, and finally to the engaged state.

Description

Technical Field

[0001] This application generally relates to clutch control systems and methods, and in particular to the control of a clutch connected to the output shaft of a motor vehicle's engine during the starting phase of the motor vehicle. Background Technology

[0002] The engine, as the power source of a motor vehicle, outputs power through its output shaft. However, because the engine's output shaft rotates at very high speeds, a gearbox (or transmission) is usually required to reduce the speed and increase torque output, which is especially important when starting the vehicle. A clutch is typically installed between the gearbox and the engine's output shaft to connect the engine's output shaft and the gearbox's input shaft as needed.

[0003] For example, a clutch typically includes two pairs of clutch plates, each pair of which may consist of multiple clutch plates. These two pairs of clutch plates are arranged axially staggered. One pair of clutch plates is configured to be fixedly connected to the clutch input shaft, and the other pair is configured to be fixedly connected to the clutch output shaft. Furthermore, the clutch input shaft and output shaft are connected to the engine output shaft and the transmission input shaft, respectively. These two pairs of clutch plates can be driven axially to move relative to each other via an actuator, such as a hydraulic actuator, to press them together axially and prevent relative movement, thus allowing them to rotate together. In this state, the clutch is engaged, and power can be transmitted from the input shaft to the output shaft. Simultaneously, when the actuator is unloaded, the two pairs of clutch plates are axially separated by a pre-installed spring, meaning the clutch is disengaged, and power cannot be transmitted from the input shaft to the output shaft.

[0004] However, when a motor vehicle switches from a stationary state (such as idling) to a low-speed driving state or from a low-speed driving state to a high-speed driving state, the clutch needs to be in a state between the above-mentioned engaged state and disengaged state. That is, at this time, the two clutch plates are in a state of sliding friction, so as to avoid the vibration caused by the sudden change of torque of the power source being transmitted to the vehicle body through the clutch or to avoid the overall load being transmitted to the power source in the reverse direction through the clutch, causing the speed fluctuation of the power source.

[0005] Due to the operating characteristics of the engine, when the vehicle is stationary and the driver presses the accelerator pedal, a certain amount of time is required to ensure that the engine output shaft speed increases to a specific value before the clutch can engage. Alternatively, when the vehicle is traveling at low speeds, the constant shifting of gears in the transmission may cause the clutch to be in a slipping state, resulting in prolonged clutch plate friction and increased wear. Furthermore, if the engine output shaft speed is mismatched or the vehicle load is low, failure to engage the clutch at the appropriate time can easily cause impact to the clutch shaft, affecting the smoothness of the vehicle's ride and the clutch's lifespan. Summary of the Invention

[0006] To address the aforementioned problems, this application aims to propose a novel clutch control system and method, thereby ensuring the power and smoothness of motor vehicle start-up, preventing axle impact, and improving clutch service life.

[0007] According to one aspect of this application, a clutch control method for a motor vehicle engine is provided, wherein the rotating shaft of the motor vehicle engine is connected to a transmission via a clutch, the clutch being controllable to switch between a disengaged state, a slipping state, and an engaged state, the method comprising:

[0008] The engine speed during the starting process of a motor vehicle is divided into three speed regions: low speed starting region, medium speed starting region, and high speed starting region.

[0009] Different engine speed control paths are pre-planned for each of the three divided speed zones;

[0010] After the vehicle starts, the rotational speed of the engine's rotating shaft is measured. Based on the rotational speed range of the measured engine's rotating shaft, one of the planned engine speed control paths is selected to control the engine's speed.

[0011] While controlling the engine speed, the clutch is controlled to change from the disengaged state to the slipping state, and finally to the engaged state.

[0012] Optionally, the low-speed start-up region is defined as N. TgtLow -N Eng ≤Offset2, where N Eng The measured rotational speed (N) of the engine's shaft. TgtLow Offset2 is a predefined positive threshold value, representing the target speed to be controlled for low-speed start-up.

[0013] Optionally, the target speed to be controlled during the low-speed start-up...

[0014] N TgtLow =Max(N) Base N DrvShftFrz +Offset)

[0015] Where, N Base The target engine speed is determined by referring to a table based on the engine accelerator pedal characteristic distribution curve predetermined by the vehicle manufacturer; N DrvShftFrzThe input shaft speed of the transmission is frozen when the accelerator pedal opening is greater than a specific value, and is determined by looking up a table using the transmission shift logic distribution curve predetermined by the vehicle manufacturer; Offset is a correction value manually determined based on the engine accelerator pedal characteristic distribution curve and the transmission shift logic distribution curve.

[0016] Optionally, the mid-speed starting region is defined as Offset2 < N. TgtLow -N Eng <Offset1, where Offset1 is a predefined positive threshold value, determined by human experience using the engine accelerator pedal characteristic distribution curve.

[0017] Optionally, the target speed to be controlled for mid-speed start-up is

[0018] N TgtMiddle =Max(N) TgtLow N Frz Eng +Offset3)

[0019] Where, N Frz Eng N is the transmission input shaft speed that is frozen at a specific moment (e.g., 2%) when the accelerator pedal opening exceeds a certain value during mid-speed start-up. Frz Eng It is also determined by looking up the gearbox shift logic distribution curve that is predetermined by the vehicle manufacturer; Offset3 is a predetermined positive threshold and is determined by human experience with the help of the engine accelerator pedal characteristic distribution curve, where Offset3 > Offset1 > Offset2.

[0020] Optionally, the high-speed start-up region is defined as N. TgtLow -N Eng ≥Offset1.

[0021] Optionally, if the time between the clutch's expected start of the slipping state and the start of the engagement state is less than the engine's power response delay time, the rotational speed of the engine's shaft is increased before the clutch begins to engage.

[0022] Optionally, during the process of the clutch changing from the slipping state to the engaged state, the target engine speed is... Where N Clch_n The current speed of the clutch output shaft. Gain is the clutch output shaft speed at the previous moment, and Gain is a correction factor less than 1, which is pre-calibrated according to the vehicle's factory settings.

[0023] Optionally, the engine speed control path in the low-speed start-up region overlaps at least partially with the engine speed control path in the medium-speed start-up region; or, the engine speed control path in the low-speed start-up region overlaps at least partially with the engine speed control path in the high-speed start-up region; or, the engine speed control path in the medium-speed start-up region overlaps at least partially with the engine speed control path in the high-speed start-up region.

[0024] Optionally, the characteristic is that each engine speed control path is pre-planned to avoid or mitigate clutch impact on the shaft.

[0025] According to another aspect of this application, a clutch control system for a motor vehicle engine is also provided, wherein the rotating shaft of the motor vehicle engine is connected to a gearbox via a clutch, the engine is equipped with an engine controller, the clutch is equipped with a clutch control unit, the clutch control system includes a computer and a memory, the computer is connected to the engine controller and the clutch control unit respectively to control them, and the memory stores a computer program that can be called and executed by the computer to perform the aforementioned method.

[0026] By employing the technical means described above in this application, it is possible to ensure the starting power and smoothness of the motor vehicle while preventing clutch wear, increasing its service life, and avoiding impact on the axle. Attached Figure Description

[0027] A more comprehensive understanding of the principles and aspects of this application will be gained from the detailed description below, in conjunction with the accompanying drawings. It should be noted that the scale of the drawings may vary for clarity, but this will not affect the understanding of this application. In the drawings:

[0028] Figure 1 The illustration schematically shows a clutch control system according to an embodiment of the present application, which is applied to the drivetrain control of a motor vehicle;

[0029] Figure 2A The illustration shows the shaft impact caused by a clutch according to existing technology when the engine output shaft of a motor vehicle starts at low speed;

[0030] Figure 2B The illustration shows the shaft impact caused by a clutch according to existing technology when the engine output shaft of a motor vehicle starts at high speed;

[0031] Figure 2C This illustration illustrates another scenario of shaft impact generated by a clutch in the prior art during high-speed start-up of a motor vehicle's engine output shaft.

[0032] Figure 3 A flowchart illustrating a clutch control method according to an embodiment of this application is shown schematically;

[0033] Figure 4 The diagram schematically illustrates the rotational speed trend of the engine's rotating shaft corresponding to the clutch control method of this application. Detailed Implementation

[0034] In the accompanying drawings of this application, features with the same structure or similar function are indicated by the same reference numerals.

[0035] Figure 1 The diagram schematically illustrates a motor vehicle drivetrain, in which a clutch control system 100 according to an embodiment of this application may be provided, for example. In this drivetrain, the motor vehicle's engine 200 serves as a power source, outputting power via its rotating shaft. The rotating shaft of the engine 200 is connected to a gearbox (or transmission) 400 via a clutch 300. The clutch 300 includes an input shaft end connected to the rotating shaft of the engine 200 and an output shaft end connected to the gearbox 400. The gearbox 400 is operatively connected to wheels 500 to provide torque to drive the wheels 500 to rotate. The clutch 300 also includes (not shown) two sets of clutch plates, each set of which may consist of multiple clutch plates, the two sets of clutch plates being axially staggered, one set of clutch plates being configured to be fixedly connected to the input shaft end, and the other set of clutch plates being configured to be fixedly connected to the output shaft of the clutch. The two sets of clutch plates of clutch 300 can be driven to move axially relative to each other by an actuator such as a hydraulic actuator, so that they are pressed together axially and cannot move relative to each other, so that they can rotate together. At this time, the clutch is engaged and power can be transmitted from the input shaft end to the output shaft end. At the same time, when the actuator is unloaded, the two sets of clutch plates are axially separated by the action of a pre-equipped spring. At this time, the clutch is disengaged and power cannot be transmitted from the input shaft end to the output shaft end.

[0036] The engine 200 is equipped with an engine controller (EMS) 210, which controls the operation of the engine 200. The clutch 300 is equipped with a clutch control unit (TCU) 310 to control the operation of its actuator. The clutch control system 100 of this application is electrically connected to the engine controller 210 and the clutch control unit 310 respectively to send control commands to both and perform corresponding actions. In addition, the clutch control system 100 can also receive corresponding operating data of the engine 200 and the clutch 300 from them respectively.

[0037] Figure 2AThe diagram illustrates the changes in engine rotational speed and clutch output shaft speed during the process of a motor vehicle moving from a standstill to starting, according to a traditional clutch control method. R represents the engine rotational speed curve, C represents the clutch output shaft speed curve, the horizontal axis represents time, and the vertical axis represents speed.

[0038] Starting at time t0, the two sets of clutch plates of clutch 300 just begin to engage, causing the output shaft of clutch 300 to begin rotating. Due to the operating characteristics of engine 200, the rotational speed of engine 200's shaft continues to rise when the two sets of clutch plates just begin to engage and relative slippage still exists between them. However, as the two sets of clutch plates are continuously clamped axially, the drag force on engine 200's shaft increases, causing the rotational speed of engine 200's shaft to begin to decrease. During this process, the rotational speed of clutch 300's output shaft continues to increase. At time t... 11 At this point, the two sets of clutch plates of clutch 300 are fully clamped, meaning there is no longer any sliding friction between them. At this time, the engine 200 is significantly dragged by the transmission 400 via clutch 300, causing a significant decrease in the rotational speed of the engine 200's shaft, thus generating a shaft impact on clutch 300. At times t0 and t... 11 During the time interval HM1, the two sets of clutch plates of clutch 300 are always in a state of slip friction. That is, there is always sliding friction between these two sets of clutch plates. If at t... 11 At time t, the rotational speed of the engine shaft at time 200 drops too quickly, or rather, near time t... 11 If the downward trend of the rotational shaft speed curve of engine 200 is too steep, it often means that if at time t... 11 The impact on the shaft generated by clutch 300 is relatively large, which will affect the driving smoothness of the entire vehicle. Observing the trend of the curve changes, if the slopes of curves R and C at time t11 are similar, then this impact on the shaft will be smaller.

[0039] Figure 2B This illustration shows the changes in engine shaft speed and clutch output shaft speed during the process of a vehicle moving from a standstill to a start, according to a conventional clutch control method. To achieve superior acceleration, the driver sometimes presses the accelerator pedal before the clutch begins to slip. However, if the vehicle itself is heavy or under a heavy load, the engine shaft 200 will experience significant drag from the transmission 400 when the clutch 300 is engaged. Figure 2BThis situation is illustrated in the diagram. As can be seen from the diagram, starting from time t0, the two sets of clutch plates of clutch 300 just begin to engage, thus causing the output shaft of clutch 300 to begin rotating. Since the engine 200's rotating shaft rotates at a high speed before time t0, the rotational speed of the engine 200's rotating shaft decreases over time due to slippage between the two sets of clutch plates. Between time t0 and time t... 12 During the time interval HM2, the two sets of clutch plates of clutch 300 are always in a slipping state. From time t 12 Initially, clutch 300 is in a fully engaged state, meaning the two sets of clutch plates are completely clamped together, thus eliminating any sliding friction between them. Similar to... Figure 2A As shown, if at time t 12 If the slope difference between curve R and curve C is too large, it means that the rotating shaft of engine 200 is significantly dragged by the gearbox 400 through clutch 300, resulting in a significant decrease in the rotational speed of engine 200, which will affect the driving smoothness of the whole vehicle.

[0040] Figure 2C This illustration schematically shows the changes in engine shaft speed and clutch output shaft speed during the acceleration process of a vehicle from a standstill to start, according to a traditional clutch control method. In this example, to achieve superior acceleration performance, the driver sometimes presses the accelerator pedal before the clutch begins to slip. However, compared to... Figure 2B Compared to the situation, Figure 2C The scenario depicted occurs when the vehicle itself is relatively light in weight or load. In this case, if the same hydraulic force is used to clamp both clutch plates in the clutch's hydraulic actuator, the rotational speed of the engine shaft (200) cannot be reduced sufficiently, necessitating an increase in hydraulic force. This leads to an increase in the duration of slippage. For example... Figure 2C As shown, time t0 and time t 13 The duration of the representative slip-friction state between HM3 and HM3 is significantly longer than that between HM3 and HM3. Figure 2B The HM2 shown. Although this will cause at time t 13 Because the slopes of curves R and C differ, as shown in... Figure 2B The reduction in size leads to a decrease in impact on the shaft, but the increased duration of slippage can cause clutch overheating or even burning. (This is in contrast to the previous point about reducing impact on the shaft.) Figure 2CAs shown, taking a dual-clutch transmission as an example, for a dry dual-clutch transmission, the increased duration of slippage will generate high temperatures. These high temperatures will have an irreversible effect on the diaphragm spring crystals in the dry dual-clutch transmission, thereby affecting the characteristics of the diaphragm spring and consequently changing the characteristics of the clutch itself, thus affecting the driving performance of the vehicle. For a wet dual-clutch transmission, since the lubricating oil cannot carry away the heat generated by the high temperature sufficiently, it will cause clutch erosion.

[0041] Figure 3 A flowchart illustrating a clutch control method according to an embodiment of this application is shown schematically; Figure 4 The diagram schematically illustrates the rotational speed trend of the engine's rotating shaft corresponding to the clutch control method of this application. The clutch control system 100 includes a computer and memory. The computer is connected to the engine controller 210 and the clutch control unit 310 respectively to control them. Those skilled in the art will understand that the clutch control method of this application can be stored as a computer program in the memory of the clutch control system 100 and executed by the computer when needed.

[0042] The clutch control method of this application is mainly applied to the starting driving process when the vehicle speed is between 0 and 20 km / h, while the rotational speed of the engine 200 shaft is between 750 rpm and 6500 rpm.

[0043] First, in step S5, it is determined whether the vehicle is currently in the starting phase. This can be achieved, for example, by measuring values ​​from a series of sensors installed on the vehicle's body, such as acceleration sensors and wheel speed sensors. As an example, the vehicle is identified as stationary if both the acceleration sensor and wheel speed sensors show a zero reading, while the driver's intention to initiate the starting phase is confirmed by the pressing of the accelerator pedal.

[0044] In step S10, three starting speed ranges are defined: a low-speed starting range, a medium-speed starting range, and a high-speed starting range. According to the clutch control method of this application, the division of these three starting speed ranges is implemented as follows.

[0045] Before a vehicle leaves the factory, tests are typically conducted to determine the matching characteristics between the engine 200 and the degree of pressure applied to the accelerator pedal, and this is recorded as an engine accelerator pedal characteristic distribution curve (Pedal Map). The horizontal axis of this curve represents the rotational speed of the engine 200's shaft, and the vertical axis represents the output torque of the engine 200's shaft. The characteristic distribution curve contains multiple curves, each corresponding to a different degree of accelerator pedal opening (e.g., 2% accelerator pedal opening is 2% of its maximum opening). Similarly, before a vehicle leaves the factory, a transmission shift logic distribution curve is typically determined based on the degree of pressure applied to the engine 200, transmission 400, and accelerator pedal. This distribution curve also contains multiple curves, each representing the transmission's shift points (e.g., 1st gear -> 2nd gear, 2nd gear -> 3rd gear, etc.). The vertical axis represents the accelerator pedal opening, and the horizontal axis represents the rotational speed of the engine 200's shaft.

[0046] For example, the target speed to be controlled during the initial stage can be determined according to the following formula (1):

[0047] N TgtLow =Max(N) Base N DrvShftFrz +Offset) (1)

[0048] Where, N TgtLow N is the target speed to be controlled during the initial stage. Base The target engine speed is determined by referring to a table based on the engine accelerator pedal characteristic distribution curve predetermined by the vehicle manufacturer; N DrvShftFrz The N is the transmission 400 input shaft speed that is frozen when the accelerator pedal opening is greater than a specific value (e.g., 2%). DrvShftFrz It is also determined by looking up the gearbox shift logic distribution curve that is predetermined by the vehicle manufacturer; Offset is a correction value determined manually based on the engine accelerator pedal characteristic distribution curve and the gearbox shift logic distribution curve.

[0049] In addition, N Eng The measured value of the rotational speed of the rotating shaft of engine 200 can be obtained, for example, using a speed sensor specifically configured for engine 200.

[0050] According to the provisions of this application, when N TgtLow -N Eng When the value is ≤Offset2, it is considered that the motor vehicle starts at a low speed. Here, Offset2 is a pre-defined threshold (positive value), which can be determined by human experience, for example, by using the characteristic distribution curve of the engine accelerator pedal.

[0051] Furthermore, according to the provisions of this application, when Offset2 < NTgtLow -N Eng When the offset is less than 1, the vehicle is considered to be starting at a medium speed. In this case, the target starting speed is determined according to the following formula (2).

[0052] N TgtMiddle =Max(N) TgtLow N Frz Eng +Offset3) (2)

[0053] Where, N TgtMiddle For the target speed under medium-speed start-up conditions, N Frz Eng The N is the transmission 400 input shaft speed that is frozen at the moment when the accelerator pedal opening exceeds a certain value (e.g., 2%) during mid-speed start-up. Frz Eng It can also be determined by looking up the gearbox shift logic distribution curve that is predetermined by the vehicle manufacturer; Offset3 is a predetermined threshold (positive value), which can be determined by human experience, for example, by using the engine accelerator pedal characteristic distribution curve.

[0054] Furthermore, according to the provisions of this application, when N TgtLow -N Eng When the value is greater than or equal to Offset1, it is considered that the motor vehicle starts at high speed. Offset1 is a pre-defined threshold (positive value), which can be determined by human experience using the characteristic distribution curve of the engine accelerator pedal, for example, Offset3 > Offset1 > Offset2.

[0055] Then, in step S20, it is determined whether the vehicle is in the low-speed start-up range. For example, after the accelerator pedal has been pressed, at a predetermined time t... s Measure the rotational speed N of the engine shaft of engine 200. Eng Then, using N TgtLow -N Eng ≤Offset2 determines whether the vehicle is starting at low speed. If yes, proceed to step S21; otherwise, proceed to step S30.

[0056] In step S21, refer to Figure 4 The engine controller 210 controls the rotational speed of the engine 200 shaft using path commands along curve segments 1, 2, and 6. Curve segments 2 and 6 are equal to or close to the reference target speed N. Base . Figure 4 The curve segments described herein can be pre-calibrated according to the characteristics of the motor vehicle in a manner well known to those skilled in the art. Thus, comparison... Figure 2A This application utilizes Figure 4The paths of curve segments 1, 2, and 6 can ensure that the slope of the rotational speed curve of the engine shaft of the clutch 200 is as close as possible to the slope of the output shaft segment of the clutch 300 at the beginning of the engagement state or the end of the slipping state, thereby reducing the impact of the shaft collision and ensuring the smoothness of the vehicle's ride.

[0057] In step S30, it is determined whether the vehicle is in the mid-speed start-up range. For example, using time t... s The measured rotational speed N of the engine shaft of engine 200 Eng And using Offset2<N TgtLow -N Eng <Offset1. For Figure 4 For the mid-speed start-up range, due to time t s If the position is fixed, it can be understood that curve segments 1 and 3 are shifted to the left as a whole. If the judgment result is yes, proceed to step S31; if the judgment result is no, proceed to step S32.

[0058] In step S31, the vehicle is considered to start at a medium speed. In this case, if the target speed is still determined by formula (1), the output shaft speed of engine 200 is not sufficient to meet the target, often resulting in exceeding the target speed and triggering PI adjustment of clutch 300, thus causing a starting shock. Therefore, in the case of starting at a medium speed, it is necessary to appropriately increase the target speed of engine 200, thereby increasing the smoothness of the engine (because if the engine speed does not overshoot, the overshoot control of the clutch will not be triggered) and the power of the engine (because the higher the engine speed, the faster the torque response speed of the engine). In this way, compared with Figure 2B and 2C This application utilizes Figure 4 The paths of curve segments 1, 3, and 5 can correspondingly ensure that at the start point of the clutch 300 engagement state or the end point of the slipping state, the slope of the engine 200 rotational shaft speed curve is as close as possible to the slope of the clutch 300 output shaft segment, thereby reducing shaft impact and ensuring the smoothness of the vehicle's ride. Curve segment 5 is equal to or close to the target speed N. TgtMiddle .

[0059] In step S32, the vehicle is considered to start at a high speed. In this case, this application... Figure 4 The paths of curve segments 4 and 6 control the engine speed of 200. Curve segment 4 integrates the vehicle's acceleration over time, and curve segment 6 is equal to or close to the reference target speed N. Base For curve segment 4, the engine speed frozen at the moment when the accelerator pedal opening is greater than a specific value (e.g., 2%) is N. Frz Eng Starting point, with NBase As the endpoint, the time period can be divided into multiple segments (e.g., three T1, T2, and T3). During this process, the acceleration of the rotating shaft of engine 200 is measured to be a. Ttg Then curve 4 can be represented as:

[0060]

[0061] It should be clear that the division of time periods can be increased or decreased as needed.

[0062] Regardless of whether it's step S21, S31, or S32, the process then proceeds to step S40. Clutch synchronization control is performed in step S40. During this process, it is ultimately ensured that clutch 300 is engaged. Whether targeting low, medium, or high speeds, when the engine speed of 200 is close to the target speed (for medium-speed start-up, N),... TgtMiddle For low-speed and high-speed starting, N Base To address this, the engine speed needs to be increased, for example, by using paths 7 or 8 to control the engine speed. However, determining when to increase the engine speed (or whether to increase the engine speed) requires considering the engine's power response delay. Therefore, the estimated synchronization time (i.e., the time it takes for the clutch to engage) needs to be calculated based on the speed difference between the engine speed and the output shaft speed of the clutch 300 (engine speed - clutch output shaft speed) and the rate of change of this speed difference. When the estimated synchronization time is less than the engine's power response delay time (e.g., the engine's power response delay time is typically 0.3 seconds), the rotational speed of the engine 200's rotating shaft needs to be increased (e.g., by using paths 7 or 8 to control the engine speed). In this application, the starting point for the estimated synchronization time can be a predetermined time t. s Alternatively, at some point after that moment, depending on the performance of the clutch 300, the endpoint of the expected synchronization timing is the moment when the clutch 300 is finally engaged.

[0063] by Figure 4 Taking curve segment 8 as an example, the target rotational speed during the synchronization process is determined using the following formula (4):

[0064]

[0065] Where, N TgtSyn For the target rotational speed during the synchronization process, N Clch_n The current speed of the clutch output shaft. The clutch output shaft speed is the speed at the previous moment, and Gain is a correction factor less than 1, pre-calibrated according to the vehicle's factory settings. In the described method steps, some steps, such as S5 and S10, can be interchanged as needed.

[0066] The technical solution of this application can ensure the starting power and smoothness of the motor vehicle while preventing clutch wear, increasing its service life, and avoiding impact on the axle. Although specific embodiments of this application are described in detail herein, they are given for illustrative purposes only and should not be considered as limiting the scope of this application. Furthermore, those skilled in the art will understand that the various embodiments described herein can be used in combination with each other. Various substitutions, modifications, and alterations can be conceived without departing from the spirit and scope of this application.

Claims

1. A clutch control method for a motor vehicle engine, wherein the rotating shaft of the motor vehicle engine is connected to a transmission via a clutch, the clutch being controllable to switch between a disengaged state, a slipping state, and an engaged state, the method comprising: The engine speed during the starting process of a motor vehicle is divided into three speed regions: low speed starting region, medium speed starting region, and high speed starting region. Different engine speed control paths are pre-planned for each of the three divided speed zones; After the vehicle starts, the rotational speed of the engine's rotating shaft is measured. Based on the rotational speed range of the measured engine's rotating shaft, one of the planned engine speed control paths is selected to control the engine's speed. While controlling the engine speed, the clutch is controlled to change from the disengaged state to the slipping state, and finally to the engaged state. The rate of change of the speed difference between the engine speed and the speed at the output shaft end of the clutch is determined, and the estimated time for the clutch to reach the engaged state is determined based on the rate of change of the speed difference. When the estimated time is less than the engine's power response delay time, the speed of the engine's rotating shaft is increased.

2. The clutch control method according to claim 1, characterized in that, The low-speed start-up region is defined as N. TgtLow -N Eng ≤Offset2, where N Eng The measured rotational speed (N) of the engine's shaft. TgtLow Offset2 is a predefined positive threshold value, representing the target speed to be controlled for low-speed start-up.

3. The clutch control method according to claim 2, characterized in that, The target speed N to be controlled during low-speed start-up TgtLow =Max(N) Base N DrvShftFrz +Offset) Where, N Base The target engine speed is determined by referring to a table based on the engine accelerator pedal characteristic distribution curve predetermined by the vehicle manufacturer; N DrvShftFrz The input shaft speed of the transmission is frozen when the accelerator pedal opening is greater than a specific value, and is determined by looking up a table using the transmission shift logic distribution curve predetermined by the vehicle manufacturer; Offset is a correction value manually determined based on the engine accelerator pedal characteristic distribution curve and the transmission shift logic distribution curve.

4. The clutch control method according to claim 3, characterized in that, The medium-speed starting region is defined as Offset2 < N TgtLow -N Eng <Offset1, wherein Offset1 is a preset positive threshold positive value, which is determined based on artificial experience by means of the characteristic distribution curve of an engine accelerator pedal.

5. The clutch control method according to claim 4, characterized in that, The target speed N to be controlled during mid-speed start-up TgtMiddle =Max(N) TgtLow N FrzEng +Offset3)(2) Where, N FrzEng This N represents the transmission input shaft speed that is frozen when the accelerator pedal opening exceeds a specific value during mid-speed start-up. FrzEng It is also determined by looking up the gearbox shift logic distribution curve that is predetermined by the vehicle manufacturer; Offset3 is a predetermined positive threshold and is determined by human experience with the help of the engine accelerator pedal characteristic distribution curve, where Offset3>Offset1>Offset2.

6. The clutch control method according to claim 4, characterized in that, The high-speed start-up region is defined as N. TgtLow -N Eng ≥Offset1.

7. The clutch control method according to any one of claims 1 to 6, characterized in that, If the time between the clutch's expected start of the slipping state and the start of the engagement state is less than the engine's power response delay time, then the rotational speed of the engine's shaft is increased before the clutch begins to engage.

8. The clutch control method according to any one of claims 2 to 6, characterized in that, The target engine speed during the process of the clutch changing from the slipping state to the engaged state. Where N Clch_n The current speed at the clutch output shaft end, N Clchn-1 Gain is the clutch output shaft speed at the previous moment, and Gain is a correction factor less than 1, which is pre-calibrated according to the vehicle's factory settings.

9. The clutch control method according to claim 8, characterized in that, The engine speed control path in the low-speed start-up region overlaps at least partially with the engine speed control path in the medium-speed start-up region, or the engine speed control path in the low-speed start-up region overlaps at least partially with the engine speed control path in the high-speed start-up region, or the engine speed control path in the medium-speed start-up region overlaps at least partially with the engine speed control path in the high-speed start-up region.

10. The clutch control method according to any one of claims 1 to 9, characterized in that, Each engine speed control path is pre-planned to avoid or mitigate clutch impact on the shaft.

11. A clutch control system for a motor vehicle engine, wherein the rotating shaft of the motor vehicle engine is connected to a gearbox via a clutch, the engine is equipped with an engine controller (210), the clutch is equipped with a clutch control unit (310), the clutch control system including a computer and memory, the computer being connected to the engine controller (210) and the clutch control unit (310) respectively to control them, the memory storing a computer program that can be invoked and executed by the computer to perform the method according to any one of claims 1 to 10.

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