AMT clutch control method for improving starting smoothness and vehicle
By introducing displacement offsets at the pre-engagement point and small torque point in the clutch control of AMT vehicles and using displacement change rate control, the problem of starting vibration in AMT vehicles was solved, and a smooth starting process was achieved.
Patent Information
- Application Number
- CN202310956464.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-31
- Publication Date
- 2025-12-05
- Estimated Expiration
- 2043-07-31
AI Technical Summary
When starting an AMT vehicle, excessive clutch travel or excessive torque rate during clutch control can cause start-up jerking and prevent smooth synchronization.
By setting a displacement offset between the pre-engagement point and the low torque point of the clutch, and using the displacement change rate to control the clutch, a smooth transition is ensured from the fully disengaged point to the pre-engagement point, then to the low torque point, and finally to the high torque point.
Shorten the start-up response time, avoid start-up jitter, achieve smooth clutch engagement, and improve start-up smoothness.
Smart Images
Figure CN116816828B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of vehicle control technology, specifically to an AMT clutch control method and vehicle for improving start-up smoothness. Background Technology
[0002] Currently, during the start-up process of AMT models, after the driver engages the gear and presses the accelerator, it is necessary to control the clutch to reach the target depth from the fully disengaged point through a certain torque rate, and the start-up is completed after the input shaft speed of the transmission and the engine speed are synchronized.
[0003] However, if the clutch is engaged from the point of complete disengagement when starting, the travel is too long; if the clutch is engaged slowly, i.e. the torque rate is low, the start-up response time is too long; if the clutch is engaged quickly, i.e. the torque rate is high, it will cause start-up jerking.
[0004] Based on the torque transmission characteristics of the clutch, near the clutch engagement point (the displacement point where the clutch begins to transmit torque), a large change in clutch torque corresponds to a very small change in clutch displacement. Therefore, when the torque change rate is used to control the clutch, it is easy to pass through the clutch engagement point relatively quickly, resulting in an excessive change in torque in a short period of time. This ultimately causes the input shaft speed of the transmission to vibrate in the initial stage of starting, and it cannot converge quickly thereafter. Summary of the Invention
[0005] To address the shortcomings of existing technologies, the purpose of this application is to provide an AMT clutch control method and vehicle that improves start-up smoothness, enabling relatively smooth and rapid clutch engagement during the initial stage of vehicle start-up, avoiding jitter, and shortening start-up response time.
[0006] To achieve the above objectives, the technical solution adopted is: an AMT clutch control method to improve start-up smoothness, which includes the following steps:
[0007] A pre-engagement point of the clutch is selected, the displacement value of which is greater than the displacement value of the known engagement point and less than the displacement value of the fully disengaged point; after the gear lever is engaged and before the accelerator is pressed, the ECU controls the clutch to engage from the fully disengaged point to the pre-engagement point;
[0008] Once a known torque value is selected at a low torque point, its corresponding displacement value is found. When the accelerator is pressed, the ECU begins to control the clutch from the pre-engagement point through the engagement point to the low torque point according to the set displacement change rate.
[0009] The ECU selects a high torque point with a known displacement value, and controls the clutch to engage from the low torque point to the high torque point through the selected torque change rate. After the input shaft speed and engine speed are synchronized, the clutch jumps from the high torque point to the fully engaged point, completing the vehicle start-up.
[0010] Based on the above technical solution, the pre-engagement point of the selected clutch includes:
[0011] The pre-engagement point of the clutch is based on the known clutch engagement point plus a displacement offset Δy0; wherein, the initial displacement value of the fully disengaged point is Y0, the displacement value corresponding to the known engagement point is Y1, and the displacement value of the pre-engagement point is Y1+Δy0, and it is required that Y1<Y1+Δy0<Y0.
[0012] Based on the above technical solution, the displacement offset Δy0 is obtained by calibration according to the clutch wear and temperature.
[0013] Based on the above technical solution, the clutch adopts a pneumatic clutch, and the ECU controls the clutch to engage from the fully disengaged point to the pre-engaged point; the ECU starts to control the clutch from the pre-engaged point through the engagement point to the small torque point according to a set displacement change rate; or the ECU controls the clutch from the small torque point to the set large torque point by a set torque change rate, including:
[0014] The ECU controls the exhaust volume of the pneumatic clutch through the clutch solenoid valve, thereby controlling the clutch to engage from one position point to another.
[0015] Based on the above technical solution, finding the corresponding displacement value of a selected small torque point with a known torque value includes:
[0016] Select a small torque point tq1 with a known torque value, and find the corresponding displacement value y1 based on the torque value and the clutch torque-displacement curve, satisfying y1<Y1;
[0017] The torque value corresponding to the small torque point is within the range of 0 to 100 N·m.
[0018] Based on the above technical solution, the displacement offset Δy0 is 2.5mm, the torque value of the small torque point tq1 is 20N·m, the displacement value y1 is obtained by looking up the table according to the clutch torque-displacement curve, and the set displacement change rate dy is -20mm / s.
[0019] Based on the above technical solution, the selected high torque point with a known displacement value, where the ECU controls the clutch to engage from the low torque point to the high torque point through a selected torque change rate, includes:
[0020] The ECU looks up the torque change rate dtq from a table based on the throttle, load value, slope, gear, engine speed, and actual clutch torque value; the ECU also looks up the displacement value of the high torque point tq2 from a table based on the throttle, load value, slope, gear, and engine speed.
[0021] The ECU controls the clutch to engage from the low torque point tq1 to the high torque point tq2 through the torque change rate dtq.
[0022] This application also discloses a vehicle comprising an engine and a transmission. The vehicle's ECU uses the aforementioned AMT clutch control method to control the clutch. First, the clutch is controlled to engage from the fully disengaged point to the pre-engaged point. Then, the clutch is controlled to engage from the pre-engaged point to a small torque point according to a set displacement change rate. Afterward, the clutch is controlled to engage from the small torque point to a large torque point according to a selected torque change rate. The transmission input shaft speed gradually increases from the engagement point until the large torque point, and the transmission input shaft speed is equal to the engine speed.
[0023] Based on the above technical solution, the pre-engagement point of the selected clutch includes:
[0024] The pre-engagement point of the clutch is based on the known clutch engagement point plus a displacement offset Δy0; wherein, the initial displacement value of the fully disengaged point is Y0, the displacement value corresponding to the known engagement point is Y1, and the displacement value of the pre-engagement point is Y1+Δy0, and it is required that Y1<Y1+Δy0<Y0.
[0025] Based on the above technical solution, the clutch adopts a pneumatic clutch, and the ECU controls the clutch to engage from the fully disengaged point to the pre-engaged point; the ECU starts to control the clutch from the pre-engaged point through the engagement point to the small torque point according to a set displacement change rate; or the ECU controls the clutch from the small torque point to the set large torque point by a set torque change rate, including:
[0026] The ECU controls the exhaust volume of the pneumatic clutch through the clutch solenoid valve, thereby controlling the clutch to engage from one position point to another.
[0027] The beneficial effects of the technical solution provided in this application include:
[0028] 1. The AMT clutch control method and vehicle of this application first select the pre-engagement point of the clutch. The pre-engagement point is located between the engagement point and the fully disengagement point. After the gear lever is engaged and before the accelerator is pressed, the ECU controls the clutch to engage from the fully disengagement point to the pre-engagement point. Before the accelerator is pressed, the AMT clutch control method engages from the fully disengagement point to the pre-engagement point, which is equivalent to completing part of the control process in advance and effectively shortening the start-up response time.
[0029] After selecting a low torque point, the engagement point is located between the low torque point and the pre-engagement point. When the accelerator is pressed, the ECU begins to smoothly engage the clutch from the pre-engagement point through the engagement point to the low torque point according to the set displacement change rate. The position before and after the engagement point is controlled by the displacement change rate, which is more stable than the existing technology that controls by the torque change rate. It achieves smooth transition control. The control at the position before and after the engagement point, which is most prone to vibration, is smooth and clever, effectively avoiding vibration in the initial stage of starting.
[0030] 2. The AMT clutch control method and vehicle of this application set a pre-engagement point and a small torque point, which are combined, i.e., y1 < Y1 < Y1 + Δy0, where y1 is the displacement value of the small torque point, Y1 is the displacement value of the engagement point, and Y1 + Δy0 is the displacement value of the pre-engagement point. This application uses the small torque point and the pre-engagement point as auxiliary control points to effectively define the two sides of the engagement point. The pre-engagement point and the small torque point are combined to form a small control range (Y1 + Δy0 to y1), which includes the engagement point. Within this small control range, a set displacement change rate is used for control, replacing the traditional torque change rate control method. This avoids the situation in the prior art where the engagement point is passed relatively quickly. The AMT clutch control method of this application can stably and smoothly pass from the pre-engagement point through the engagement point and then to the small torque point, effectively preventing jitter in the initial stage of starting. Attached Figure Description
[0031] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0032] Figure 1 This is a flowchart of the AMT clutch control method of this application.
[0033] Figure 2 The graphs provided for embodiments of this application are gear curves, throttle curves, and clutch displacement curves, with time as the horizontal axis.
[0034] Figure 3 This is a graph of throttle, speed, and clutch displacement versus time for existing AMT clutch control methods (only including curves from the preselected engagement point to the low torque point).
[0035] Figure 4 The graphs of throttle, speed and clutch displacement relative to time for the AMT clutch control method of this application (only the curves within the time period from the full disengagement point to the low torque point are included). Detailed Implementation
[0036] To make the objectives, technical solutions, and advantages of this application clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
[0037] like Figure 1 As shown, this application discloses an AMT clutch control method to improve start-up smoothness, characterized by comprising the following steps:
[0038] Based on the known clutch torque-displacement characteristic curve, the pre-engagement point of the clutch is selected. Specifically, the clutch torque-displacement characteristic curve is the known curve after the clutch model is determined. The displacement value of the pre-engagement point is greater than the known engagement point displacement value, and less than the full disengagement point displacement value; that is, the pre-engagement point displacement value lies between the engagement point displacement value and the full disengagement point displacement value (see...). Figure 2 Specifically, the engagement point is the displacement point at which the clutch begins to transmit torque. After the gear lever is engaged and before the accelerator is pressed, the ECU controls the clutch to engage from the fully disengaged point to the pre-engaged point. Engaging from the fully disengaged point to the pre-engaged point before the accelerator is pressed can effectively shorten the start-up response time.
[0039] Based on the clutch torque-displacement characteristic curve, a small torque point with a known torque value is selected. The ECU then uses the clutch torque-displacement characteristic curve to find the corresponding displacement value for this small torque point. When the accelerator is pressed, the ECU begins to engage the clutch from the pre-engagement point through the engagement point to the small torque point according to the set displacement change rate. That is, the position before and after the engagement point is controlled by the displacement change rate, rather than by the torque change rate, achieving a smooth transition and effectively avoiding vibration.
[0040] After the low torque point, the clutch returns to normal control. The ECU controls the clutch to engage from the low torque point to the selected high torque point through the set torque change rate. After the input shaft speed and engine speed are synchronized, the clutch jumps from the high torque point to the fully engaged point, completing the vehicle start-up.
[0041] The AMT clutch control method of this application first selects the pre-engagement point of the clutch, which is located between the engagement point and the fully disengaged point. After the gear lever is engaged and before the accelerator is pressed, the ECU controls the clutch to engage from the fully disengaged point to the pre-engagement point. Before the accelerator is pressed, this AMT clutch control method engages from the fully disengaged point to the pre-engagement point, which is equivalent to completing part of the control process in advance and effectively shortening the start-up response time.
[0042] After selecting a low torque point, the engagement point is located between the low torque point and the pre-engagement point. When the accelerator is pressed, the ECU begins to smoothly engage the clutch from the pre-engagement point through the engagement point to the low torque point according to the set displacement change rate. The position before and after the engagement point is controlled by the displacement change rate, which is more stable than the existing technology that controls by the torque change rate. It achieves smooth transition control. The control at the position before and after the engagement point, which is most prone to vibration, is smooth and clever, effectively avoiding vibration in the initial stage of starting.
[0043] In one embodiment, a pre-engagement point of the clutch is first selected, located between the engagement point and the full disengagement point. After shifting gears and before the accelerator is depressed, the ECU controls the clutch to engage from the full disengagement point to the pre-engagement point. Then, a low-torque point is selected, with the engagement point located between the low-torque point and the pre-engagement point. When the accelerator is depressed, the ECU begins to smoothly engage the clutch from the pre-engagement point through the engagement point to the low-torque point according to a set displacement change rate. After the low-torque point, the clutch is again controlled to engage from the low-torque point to the selected high-torque point and then to the full engagement point using a selected torque change rate. Based on the above technical solution, selecting the pre-engagement point of the clutch specifically includes:
[0044] The pre-engagement point of the clutch is obtained by adding a displacement offset Δy0 to the known clutch engagement point. The initial displacement value of the fully disengaged point is Y0, the displacement value corresponding to the known engagement point is Y1, and the displacement value of the pre-engagement point is Y1+Δy0. It is required that Y1<Y1+Δy0<Y0.
[0045] The AMT clutch control method of this application obtains a pre-engagement point by adding a displacement offset Δy0 to the clutch engagement point, which serves as an auxiliary control point. This effectively defines one side of the engagement point. The pre-engagement point and the small torque point are combined to form a small control range that includes the engagement point. Within this small control range, a set displacement change rate is used for control, replacing the traditional torque change rate control method. This avoids the situation in the prior art where the clutch passes through the engagement point relatively quickly. The AMT clutch control method of this application can stably and smoothly pass from the pre-engagement point through the engagement point and then to the small torque point, effectively preventing jitter in the initial stage of start-up.
[0046] In one embodiment, a pre-engagement point of the clutch is first selected, located between the engagement point and the fully disengaged point. After shifting gears and before the accelerator is depressed, the ECU controls the clutch to engage from the fully disengaged point to the pre-engagement point. Then, a low torque point is selected, with the engagement point located between the low torque point and the pre-engagement point. When the accelerator is depressed, the ECU begins to smoothly engage the clutch from the pre-engagement point through the engagement point to the low torque point according to a set displacement change rate. After the low torque point, the clutch is again controlled to engage from the low torque point to the selected high torque point and then to the fully engaged point using the selected torque change rate. Based on the above technical solution, the displacement offset Δy0 is further calibrated based on the clutch wear and ambient temperature. Specifically, the greater the clutch wear, the smaller the displacement offset Δy0; the higher the ambient temperature, the larger the displacement offset Δy0. A suitable displacement offset Δy0 is obtained through extensive experimental data calibration. In other embodiments, the displacement offset Δy0 is affected not only by the main factors (clutch wear and ambient temperature) but also by some other secondary factors.
[0047] In one embodiment, a pre-engagement point of the clutch is first selected, located between the engagement point and the fully disengaged point. After shifting gears and before the accelerator is depressed, the ECU controls the clutch to engage from the fully disengaged point to the pre-engagement point. Then, a low torque point is selected, with the engagement point located between the low torque point and the pre-engagement point. When the accelerator is depressed, the ECU begins to smoothly engage the clutch from the pre-engagement point through the engagement point to the low torque point according to a set displacement change rate. After the low torque point, the clutch is again controlled to engage from the low torque point to the selected high torque point and then to the fully engaged point using a selected torque change rate. Based on the above technical solution, a pneumatic clutch is used. The ECU controls the clutch to engage from the fully disengaged point to the pre-engagement point, the ECU begins to control the clutch to engage from the pre-engagement point through the engagement point to the low torque point according to a set displacement change rate, and the ECU controls the clutch to engage from the low torque point to the set high torque point using a set torque change rate. All of these use the same control method: the ECU controls the exhaust volume of the pneumatic clutch through a clutch solenoid valve, thereby controlling the clutch to engage from one position point to another.
[0048] The only difference is that the ECU initially controls the clutch from the pre-engagement point through the engagement point to the low torque point according to the set displacement change rate. At this point, the exhaust volume of the pneumatic clutch is related to the displacement change rate. Conversely, the ECU controls the clutch from the low torque point to the set high torque point by setting the torque change rate. In this case, the exhaust volume of the pneumatic clutch is related to the torque change rate.
[0049] 5. AMT clutch control method for improving smoothness in the initial stage of start-up as described in claim 2, characterized in that, in one embodiment, a pre-engagement point of the clutch is first selected, the pre-engagement point being located between the engagement point and the fully disengaged point. After the gear lever is engaged and before the accelerator is depressed, the ECU controls the clutch to engage from the fully disengaged point to the pre-engagement point. Then, a small torque point is selected, the engagement point being located between the small torque point and the pre-engagement point. When the accelerator is depressed, the ECU begins to smoothly engage the clutch from the pre-engagement point through the engagement point to the small torque point according to a set displacement change rate. After the small torque point, the clutch is again controlled to engage from the small torque point to the selected large torque point and then to the fully engaged point through the selected torque change rate. Based on the above technical solution, for a small torque point with a known torque value, its corresponding displacement value is found, including:
[0050] For a selected small torque point tq1 with a known torque value, the corresponding displacement value y1 is found based on the torque value and the clutch torque-displacement characteristic curve, satisfying y1 < Y1;
[0051] The torque value corresponding to the small torque point is within the range of 0 to 100 N·m.
[0052] The small torque point set in this application, combined with the pre-engagement point mentioned earlier, is...
[0053] y1<Y1<Y1+△y0<Y0
[0054] Where y1 is the displacement value of the small torque point, Y1 is the displacement value of the engagement point, and Y1+Δy0 is the displacement value of the pre-engagement point. The AMT clutch control method of this application effectively defines the other side of the engagement point by selecting the small torque point as an auxiliary control point. The pre-engagement point and the small torque point combine to form a small control range (Y1+Δy0 to y1), encompassing the engagement point. Within this small control range, a set displacement change rate is used for control, replacing the traditional torque change rate control method. This avoids the situation in existing technologies where the engagement point is passed relatively quickly. The AMT clutch control method of this application can stably and smoothly pass from the pre-engagement point through the engagement point to the small torque point, effectively preventing jitter during the initial stage of start-up.
[0055] In one embodiment, a pre-engagement point of the clutch is first selected, located between the engagement point and the full disengagement point. After shifting gears and before the accelerator is depressed, the ECU controls the clutch to engage from the full disengagement point to the pre-engagement point. Then, a low torque point is selected, with the engagement point located between the low torque point and the pre-engagement point. When the accelerator is depressed, the ECU begins to smoothly engage the clutch from the pre-engagement point through the engagement point to the low torque point according to a set displacement change rate. After the low torque point, the clutch is again controlled to engage from the low torque point to the selected high torque point and then to the full engagement point using a selected torque change rate. Based on the above technical solution,
[0056] The displacement offset Δy0 is 2.5mm, the torque value of the small torque point tq1 is 20N·m, and the displacement value y1 corresponding to 20N·m is obtained by looking up the table according to the clutch torque-displacement curve; the set displacement change rate dy is -20mm / s.
[0057] By controlling the above data, the AMT clutch control method of this application can engage the clutch relatively smoothly and quickly in the initial stage of vehicle start-up, avoiding shuddering and shortening the start-up response time.
[0058] In one embodiment, a pre-engagement point of the clutch is first selected, located between the engagement point and the full disengagement point. After shifting gears and before the accelerator is depressed, the ECU controls the clutch to engage from the full disengagement point to the pre-engagement point. Then, a low-torque point is selected, with the engagement point located between the low-torque point and the pre-engagement point. When the accelerator is depressed, the ECU begins to smoothly engage the clutch from the pre-engagement point through the engagement point to the low-torque point according to a set displacement change rate. After the low-torque point, the clutch is again controlled to engage from the low-torque point to the selected high-torque point and then to the full engagement point using a selected torque change rate. Based on the above technical solution, selecting a high-torque point with a known displacement value, the ECU controls the clutch to engage from the low-torque point to the high-torque point using a selected torque change rate, including:
[0059] The ECU is calibrated in advance using a large amount of data on throttle, load, slope, gear, engine speed, and actual clutch torque to obtain the corresponding torque change rate. In the control process after the small torque point, the ECU looks up the torque change rate dtq in a table based on the actual throttle, load, slope, gear, engine speed, and actual clutch torque.
[0060] The ECU is calibrated in advance using a large amount of data on throttle, load, slope, gear, and engine speed to obtain the displacement value of the corresponding high torque point; in the control process after the low torque point, the ECU looks up the displacement value of the high torque point tq2 based on the throttle, load, slope, gear, and engine speed.
[0061] The ECU controls the clutch to engage from the low torque point tq1 to the high torque point tq2 through the torque change rate dtq.
[0062] The AMT clutch control method of this application returns to the normal torque change rate after passing the engagement point, and performs normal vehicle start-up.
[0063] In a specific example, the existing AMT clutch control method is as follows: Figure 3 As shown, the AMT clutch control method of this application is as follows: Figure 4 As shown, from Figure 3As can be seen in region A, the input shaft speed of the transmission will fluctuate significantly near the engagement point in the initial stage of starting. Specifically, the time from pressing the accelerator at point C to the first fluctuation point D of the transmission input shaft is 380ms, and the first peak of the input shaft is 309rpm, with large fluctuations.
[0064] The area near the engagement point using the AMT clutch control method of this application is as follows: Figure 4 In region B, there was no shaking, and the speed was stable and balanced. Specifically, the time from pressing the accelerator at point E to the first fluctuation of the input shaft at point F was 300ms, and the first peak of the input shaft was 11rpm, with basically no fluctuation.
[0065] This application also discloses a vehicle comprising an engine and a transmission. The vehicle's ECU uses the aforementioned AMT clutch control method to control the clutch. The ECU first controls the clutch to engage from the fully disengaged point to the pre-engaged point, then controls the clutch to engage from the pre-engaged point through the engagement point to the low torque point according to a set displacement change rate. Subsequently, it controls the clutch to engage from the low torque point to the high torque point according to a selected torque change rate. The transmission input shaft speed gradually increases from the engagement point until the high torque point, at which point the transmission input shaft speed equals the engine speed. Specifically, when the transmission input shaft speed at the high torque point equals the engine speed, i.e., the input shaft speed and engine speed are synchronized, the clutch will directly jump from the high torque point to the fully engaged point.
[0066] In the vehicle using the AMT clutch control method described in this application, the ECU first controls the clutch to engage from the fully disengaged point to the pre-engaged point. Then, according to a set displacement change rate, it controls the clutch to engage from the pre-engaged point through the engagement point to the low torque point. Afterward, according to a selected torque change rate, it controls the clutch to engage from the low torque point to the high torque point. Before the accelerator is pressed, this AMT clutch control method engages from the fully disengaged point to the pre-engaged point, which is equivalent to completing part of the control process in advance, effectively shortening the start-up response time. Then, a low torque point is selected, and the engagement point is located between the low torque point and the pre-engaged point. When the accelerator is pressed, the ECU begins to smoothly engage the clutch from the pre-engaged point through the engagement point to the low torque point according to a set displacement change rate. The control before and after the engagement point is achieved through displacement change rate, which is smoother than the existing technology that uses torque change rate control. It achieves smooth transition control, and the control at the most prone to vibration before and after the engagement point is smooth and skillful, effectively avoiding vibration in the initial stage of start-up.
[0067] In one embodiment, for a vehicle using the AMT clutch control method, selecting the pre-engagement point of the clutch specifically includes:
[0068] The pre-engagement point of the clutch is obtained by adding a displacement offset Δy0 to the known clutch engagement point. The initial displacement value of the fully disengaged point is Y0, the displacement value corresponding to the known engagement point is Y1, and the displacement value of the pre-engagement point is Y1+Δy0. It is required that Y1<Y1+Δy0<Y0.
[0069] The vehicle using the AMT clutch control method of this application obtains a pre-engagement point by adding a displacement offset Δy0 to the clutch engagement point, which serves as an auxiliary control point. This effectively defines one side of the engagement point. The pre-engagement point and the small torque point are combined to form a small control range that includes the engagement point. Within this small control range, a set displacement change rate is used for control, replacing the traditional torque change rate control method. This avoids the situation in the prior art where the engagement point is passed relatively quickly. The AMT clutch control method of this application can stably and smoothly pass from the pre-engagement point through the engagement point and then to the small torque point, effectively preventing jitter in the initial stage of starting.
[0070] In one embodiment, for a vehicle using the AMT clutch control method, the displacement offset Δy0 is further calibrated based on the clutch wear and ambient temperature. Specifically, the greater the clutch wear, the smaller the displacement offset Δy0; the higher the ambient temperature, the larger the displacement offset Δy0; a suitable displacement offset Δy0 is obtained through calibration using a large amount of experimental data. In other embodiments, the displacement offset Δy0 is affected not only by the primary factors (clutch wear and ambient temperature) but also by some other secondary factors.
[0071] In one embodiment, for a vehicle using the AMT clutch control method, the clutch is a pneumatic clutch. The ECU controls the clutch to engage from the fully disengaged point to the pre-engaged point, the ECU starts to control the clutch to engage from the pre-engaged point through the engagement point to the low torque point according to the set displacement change rate, and the ECU controls the clutch to engage from the low torque point to the set high torque point by the set torque change rate. All of these use the same control method, that is, the ECU controls the exhaust volume of the pneumatic clutch through the clutch solenoid valve, thereby controlling the clutch to engage from one position point to another.
[0072] The only difference is that the ECU initially controls the clutch from the pre-engagement point through the engagement point to the low torque point according to the set displacement change rate. At this point, the exhaust volume of the pneumatic clutch is related to the displacement change rate. Conversely, the ECU controls the clutch from the low torque point to the set high torque point by setting the torque change rate. In this case, the exhaust volume of the pneumatic clutch is related to the torque change rate.
[0073] In one embodiment, for a vehicle using the AMT clutch control method, for a selected small torque point with a known torque value, the corresponding displacement value is determined, including:
[0074] For a selected small torque point tq1 with a known torque value, the corresponding displacement value y1 is found based on the torque value and the clutch torque-displacement characteristic curve, satisfying y1 < Y1;
[0075] The torque value corresponding to the small torque point is within the range of 0 to 100 N·m.
[0076] The small torque point set in this application, combined with the pre-engagement point mentioned earlier, is...
[0077] y1<Y1<Y1+△y0<Y0
[0078] Where y1 is the displacement value of the small torque point, Y1 is the displacement value of the engagement point, and Y1+Δy0 is the displacement value of the pre-engagement point. The AMT clutch control method of this application effectively defines the other side of the engagement point by selecting the small torque point as an auxiliary control point. The pre-engagement point and the small torque point combine to form a small control range (Y1+Δy0 to y1), encompassing the engagement point. Within this small control range, a set displacement change rate is used for control, replacing the traditional torque change rate control method. This avoids the situation in existing technologies where the engagement point is passed relatively quickly. The AMT clutch control method of this application can stably and smoothly pass from the pre-engagement point through the engagement point to the small torque point, effectively preventing jitter during the initial stage of start-up.
[0079] In one embodiment, for a vehicle using the AMT clutch control method, the displacement offset Δy0 is further 2.5mm, the torque value of the small torque point tq1 is 20N·m, the displacement value y1 corresponding to 20N·m is obtained by looking up a table based on the clutch torque-displacement curve, and the set displacement change rate dy is -20mm / s.
[0080] By controlling the above data, the AMT clutch control method of this application can engage the clutch relatively smoothly and quickly in the initial stage of vehicle start-up, avoiding shuddering and shortening the start-up response time.
[0081] In one embodiment, for a vehicle using an AMT clutch control method, at a selected high torque point with a known displacement value, the ECU controls the clutch to engage from a low torque point to a high torque point via a selected torque change rate, including:
[0082] The ECU is calibrated in advance using a large amount of data on throttle, load, slope, gear, engine speed, and actual clutch torque to obtain the corresponding torque change rate. In the control process after the small torque point, the ECU looks up the torque change rate dtq in a table based on the actual throttle, load, slope, gear, engine speed, and actual clutch torque.
[0083] The ECU is calibrated in advance using a large amount of data on throttle, load, slope, gear, and engine speed to obtain the displacement value of the corresponding high torque point; in the control process after the low torque point, the ECU looks up the displacement value of the high torque point tq2 based on the throttle, load, slope, gear, and engine speed.
[0084] The ECU controls the clutch to engage from the low torque point tq1 to the high torque point tq2 through the torque change rate dtq.
[0085] The vehicle using the AMT clutch control method described in this application returns to the normal torque change rate after passing the engagement point, allowing for normal vehicle start-up.
[0086] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "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; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.
[0087] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0088] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. An AMT clutch control method for improving start-up smoothness, characterized by, It comprises the steps of: selecting a pre-engagement point of the clutch, the displacement value of the pre-engagement point being greater than the displacement value of the known engagement point and less than the displacement value of the full disengagement point; after the gear lever is engaged and before the accelerator is depressed, the ECU controls the clutch to engage from the full disengagement point to the pre-engagement point; selecting a small torque point of a known torque value, and finding the corresponding displacement value; when the accelerator is depressed, the ECU starts to control the clutch to engage from the pre-engagement point to the small torque point through the known engagement point according to a set displacement change rate; selecting a large torque point of a known displacement value, and the ECU controls the clutch to engage from the small torque point to the large torque point through a set torque change rate, and then the clutch jumps from the large torque point to the full engagement point after the input shaft speed and the engine speed are synchronized, thereby completing the vehicle starting.
2. The AMT clutch control method of claim 1, wherein, The pre-engagement point of the selected clutch comprises: The pre-engagement point of the clutch is based on the known clutch engagement point and adds a displacement offset Δy0; wherein the initial displacement value of the full disengagement point is Y0, the displacement value corresponding to the known engagement point is Y1, the displacement value of the pre-engagement point is Y1+Δy0, and it is required to satisfy Y1Y1+Δy0Y0.
3. The AMT clutch control method of claim 2, wherein, The displacement offset Δy0 is obtained according to the clutch wear and temperature calibration.
4. The AMT clutch control method of improving launch smoothness according to claim 1, characterized in that, The clutch is a pneumatic clutch, the ECU controls the clutch to engage from the full disengagement point to the pre-engagement point, the ECU starts to control the clutch to engage from the pre-engagement point to the small torque point through the known engagement point according to a set displacement change rate, or the ECU controls the clutch to engage from the small torque point to a set large torque point through a set torque change rate, and comprises: The ECU controls the displacement of the pneumatic clutch through the clutch solenoid, thereby controlling the clutch to engage from one point to another point.
5. The AMT clutch control method of claim 2, wherein, The small torque point of a known torque value comprises: A small torque point tq1 of a known torque value is selected, and the corresponding displacement value y1 is found according to the torque value and the clutch torque-displacement curve, and it satisfies y1Y1; The torque value corresponding to the small torque point is within the range of 0-100 N·m.
6. The AMT clutch control method for improving the smoothness of the starting according to claim 5, wherein: The displacement offset Δy0 is 2.5 mm, the torque value of the small torque point tq1 is 20 N·m, the displacement value y1 is obtained according to the clutch torque-displacement curve, and the set displacement change rate dy is -20 mm / s.
7. The AMT clutch control method of improving launch smoothness according to claim 6, characterized in that, The large torque point of a known displacement value comprises: The ECU obtains the torque change rate dtq according to the accelerator, the load value, the slope gradient, the gear, the engine speed and the actual torque value of the clutch, and obtains the displacement value of the large torque point tq2 according to the accelerator, the load value, the slope gradient, the gear and the engine speed; The ECU controls the clutch to engage from the small torque point tq1 to the large torque point tq2 through the torque change rate dtq.
8. A vehicle comprising an engine and a transmission, characterized in that The ECU of the vehicle controls the clutch using the AMT clutch control method of claim 1, first controls the clutch to combine from the full separation point to the pre-combination point, then controls the clutch to combine from the pre-combination point to the small torque point according to the set displacement change rate, and then controls the clutch to combine from the small torque point to the large torque point according to the selected torque change rate; the speed of the gearbox input shaft gradually increases from the engagement point until the large torque point, and the speed of the gearbox input shaft is equal to the speed of the engine.
9. A vehicle as claimed in claim 8, characterised in that The pre-combination point of the selected clutch comprises: The pre-combination point of the clutch is based on the known engagement point of the clutch and adds a displacement offset Δy0; wherein the initial displacement value of the full separation point is Y0, the displacement value corresponding to the known engagement point is Y1, the displacement value of the pre-combination point is Y1+Δy0, and it is required to satisfy Y1Y1+Δy0Y0.
10. A vehicle as claimed in claim 8, wherein, The clutch is a pneumatic clutch, the ECU controls the clutch to combine from the full separation point to the pre-combination point, the ECU starts to control the clutch to combine from the pre-combination point to the small torque point through the engagement point according to the set displacement change rate, or the ECU controls the clutch to combine from the small torque point to the set large torque point through the set torque change rate, comprising: The ECU controls the displacement of the pneumatic clutch through the clutch solenoid valve, and then controls the clutch to combine from one position point to another position point.
Citation Information
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