Upshift synchronous engine speed reduction control method based on AMT clutch combination

Abstract

The invention provides an AMT (automated mechanical transmission) clutch combination-based upshift synchronous engine speed reduction control method, which comprises the following steps of: 1, after an AMT upshift instruction is sent out, performing a gear shifting synchronous state of an engine twist clearing stage, and enabling a clutch to be in a complete separation stage; 2, after gear selecting and shifting of the AMT are completed, the clutch enters a contact stage that the clutch synchronously accelerates speed reduction of an engine by combining sliding friction control; 3, after the clutch is combined to reach the contact point, the clutch enters a speed reduction stage of synchronously accelerating the speed reduction of the engine through the clutch by combining sliding friction control; fourthly, when the difference N1 between the rotating speed of the engine and the rotating speed of the input shaft of the AMT is smaller than the set speed difference, the clutch enters the ending stage that the clutch synchronously accelerates speed reduction of the engine by combining sliding friction control; and fifthly, a clutch full combination stage is started, the clutch is rapidly combined to a full combination point at the fastest combination speed, the rotating speed of the engine and the rotating speed of the input shaft of the AMT are completely synchronous, and the whole upshift process is completed.

Description

Technical Field

[0001] The invention belongs to the technical field of engines, relates to engine control, and in particular to an upshift synchronous engine speed reduction control method based on AMT clutch engagement. Background Art

[0002] For commercial vehicle transmissions, there are multiple gears and multiple ranges. In commercial vehicle manual transmissions, the driver is required to control the gear switching, which is mainly 12 gears. The current mainstream of commercial vehicle AMT (Automated Mechanical Transmission) in the market is 12 gears, 14 gears, and 16 gears. Due to the large number of gears, it is often necessary to skip gears when switching in the low-speed range. Taking 16 gears as an example, at most 4 to 5 gears can be skipped at a time. Since the engine has to wait for natural deceleration, the power interruption time during the skipping process is usually mostly in this stage. Therefore, in this process, commercial vehicle AMTs of various manufacturers have also proposed some methods to reduce the power interruption time. For example, calling the engine cylinder brake or exhaust brake in the synchronization stage to assist the engine in deceleration can achieve a good deceleration effect. However, the reliability of the cylinder brake and exhaust brake of some engines cannot meet the use requirements of frequent shifting calls. Some of them cannot meet the better use requirements due to large system delays and poor control effects. Summary of the invention

[0003] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method for controlling the synchronous engine speed reduction during upshifting based on the engagement of an AMT clutch, so as to solve the technical problem in the prior art that the power interruption time during the acceleration and deceleration process of the engine of a commercial vehicle needs to be further shortened.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0005] A method for controlling engine speed reduction during upshift synchronization based on AMT clutch engagement, the method is performed according to the following steps:

[0006] Step 1: After the AMT upshift command is issued, the gear shift synchronization state of the engine torque clearing stage is carried out, and the clutch is in the complete separation stage.

[0007] Step 2: After the AMT completes the gear selection, the clutch enters the contact phase where the synchronous clutch accelerates the engine deceleration by combining slip control.

[0008] Step three, after the clutch engages and reaches the contact point, the clutch enters the deceleration stage in which the clutch accelerates the engine deceleration by engaging the slip control.

[0009] Step 4: When the speed difference △N1 between the engine speed and the input shaft speed of the AMT is less than the set speed difference, the clutch enters the end stage of synchronous clutch accelerating the engine deceleration by combining slip control.

[0010] Step five, entering the clutch full engagement stage, the clutch quickly engages towards the full engagement point at the fastest engagement speed, so that the engine speed and the input shaft speed of the AMT are completely synchronized, and the entire upshift process is completed.

[0011] The present invention also has the following technical features:

[0012] In step 2, the process of the contact phase is as follows: after the clutch is completely separated and the transmission system is disconnected, the clutch is quickly engaged to the contact point.

[0013] In step three, the process of the deceleration stage is as follows: the clutch dynamically detects the decreasing slope K of the engine speed while slipping, and when the decreasing slope K of the engine speed is less than the set slope of the target engine speed, the clutch engagement speed S is accelerated; when the decreasing slope K of the engine speed is greater than the set slope of the target engine speed, the clutch engagement speed S is reduced; when the decreasing slope K of the engine speed is equal to the set slope of the target engine speed, the clutch engagement speed S is maintained.

[0014] In step three, after the clutch displacement reaches the contact point, the AMT's TCU simultaneously detects the engine speed and water temperature signals sent by the engine's ECU, calculates the decreasing slope K of the engine speed, and the clutch calculates the engagement speed S based on the decreasing slope K of the engine speed.

[0015] In step 4, the process of the end stage is: when the speed difference △N1 between the engine speed and the input shaft speed of the AMT is less than the set speed difference, the clutch displacement reaches the displacement synchronization point.

[0016] The method adopts an upshift synchronous engine speed reduction control system based on AMT clutch engagement.

[0017] The upshift synchronous engine speed reduction control system based on AMT clutch engagement includes an ECU and a TCU respectively connected to the CAN line; the ECU is connected to the engine through a hard line; and the TCU is connected to the AMT through a hard line.

[0018] The engine is connected to one end of the clutch through a transmission system; the AMT is connected to the other end of the clutch through a transmission system.

[0019] The clutch is connected to the clutch actuator via a hard wire, and the clutch actuator is connected to the TCU via a hard wire.

[0020] Compared with the prior art, the present invention has the following technical effects:

[0021] (I) The method of the present invention is a method for effectively utilizing clutch slip control to accelerate and decelerate the engine. The present invention can shorten the power interruption time during the AMT shifting process, improve power connection, effectively avoid problems such as cyclic shifting and upshifting, enhance the driver's driving experience when the AMT shifts, and improve power connection performance.

[0022] (II) In the process of shifting, after the AMT completes the gear switching operation, the method of the present invention enters the clutch synchronization time to wait for the engine to naturally decelerate. During this period, the clutch slip control is used to gradually reduce the engine speed through the vehicle output shaft end where the clutch is slipping. The clutch engagement speed slip control needs to fully consider the clutch engagement speed to prevent the clutch from engaging too quickly, causing violent vibration of the transmission system and causing a serious decrease in comfort. The engagement speed S during the clutch slip process needs to consider the clutch contact point, and the engine deceleration slope K is monitored at the same time, so that the engine deceleration slope is rapidly reduced according to the expected descending slope, avoiding the clutch engagement speed being too fast, resulting in a too fast speed drop, or the clutch engagement speed being too slow, resulting in a too slow speed drop that fails to achieve the expected effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the connection relationship of the upshift synchronous engine speed reduction control system based on the AMT clutch engagement.

[0024] Figure 2 It is a schematic diagram of the principle of the upshift synchronous engine speed reduction control method based on the AMT clutch engagement.

[0025] Figure 3 The figure is a flow chart of the method for controlling the engine speed reduction during upshifting and synchronously with the AMT clutch engagement.

[0026] The meanings of the numbers in the figure are: 1-ECU, 2-TCU, 3-CAN line, 4-hard line, 5-engine, 6-AMT, 7-clutch, 8-clutch actuator, 9-transmission system.

[0027] The specific contents of the present invention are further explained in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0028] It should be noted that, unless otherwise specified, all mechanisms and devices in the present invention are mechanisms and devices known in the prior art.

[0029] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0030] Example:

[0031] This embodiment provides a method for controlling an upshift synchronous engine speed reduction based on the engagement of an AMT clutch. The method adopts an upshift synchronous engine speed reduction control system based on the engagement of an AMT clutch.

[0032] like Figure 1 As shown, the upshift synchronous engine speed reduction control system based on the AMT clutch engagement includes an ECU (Electronic Control Unit) 1 and a TCU (Telematics Control Unit) 2 respectively connected to a CAN (Controller Area Network) line 3; the ECU 1 is connected to the engine 5 via a hard line 4; the TCU 2 is connected to the AMT 6 via a hard line 4.

[0033] like Figure 1 As shown, the engine 5 is connected to one end of the clutch 7 through the transmission system 9; the AMT 6 is connected to the other end of the clutch 7 through the transmission system 9.

[0034] like Figure 1 As shown, the clutch 7 is connected to the clutch actuator 8 via a hard wire 4, and the clutch actuator 8 is connected to the TCU 2 via a hard wire.

[0035] In this embodiment, the clutch actuator 8 is a clutch actuator known in the art.

[0036] In this embodiment, the transmission system 9 adopts a transmission system known in the art.

[0037] The principle of this method is as follows Figure 2 As shown, Figure 2, A1 is the normal engagement displacement curve of the clutch 7 without sliding film control, A2 is the acceleration engagement displacement curve of the clutch 7 with sliding film control, A3 is the engine 5 speed reduction curve of the clutch 7 without sliding film control, A4 is the engine 5 speed reduction curve of the clutch 7 with sliding film control, A5 is the input shaft speed of AMT6, A6 is the AMT6 gear shift synchronization state, △N1 is the speed difference between the engine 5 speed and the input shaft speed of AMT6, K1 is the synchronous engine 5 speed reduction slope of the clutch without slip control, K2 is the engine 5 speed reduction slope after the clutch 7 assists the engine 5 speed reduction after slip control, S1 is the normal engagement rate of the clutch 7 without acceleration sliding film control, S2 is the engagement rate of the clutch 7 with acceleration sliding film control, C1 is the clutch 7 contact point, C2 is the displacement synchronization point of the clutch 7 when △N1 reaches the speed difference threshold, and C3 is the full engagement point of the clutch 7.

[0038] like Figure 3 As shown, the method is performed according to the following steps:

[0039] Step 1: After the upshift command of the AMT 6 is issued, the gear shift synchronization state of the engine 5 is performed in the torque clearing stage. The AMT 6 is in the gear shift synchronization state A6state=0, and the clutch 7 is in the complete separation stage.

[0040] Step 2, after the gear selection of AMT6 is completed, AMT6 is in the gear shift synchronization state A6state=1, and the clutch 7 enters the contact stage of synchronous clutch 7 accelerating the engine 5 to reduce the speed by combining the slip control.

[0041] The process of the contact phase is as follows: after the clutch 7 is completely separated from the transmission system and disconnected, the clutch 7 is quickly engaged to the contact point (ie, point C1).

[0042] Specifically in this embodiment, since the clutch 7 has no torque transmission capability before the contact point (i.e., point C1), slip control cannot be performed. The control of the clutch 7 from the complete separation point to the contact point (i.e., point C1) is to eliminate the slip idle stroke of the clutch 7, laying the foundation for subsequent precise slip control.

[0043] Step three, after the clutch 7 is engaged and reaches the contact point, the AMT 6 enters the gear shift synchronization state A6state=2, and the clutch 7 enters the deceleration phase in which the clutch 7 accelerates the engine 5 by engaging the slip control.

[0044] In step three, the process of AMT6 entering the gear shift synchronization state A6state=2 is as follows: after the clutch 7 is displaced to reach the contact point (i.e., point C1), the TCU2 of AMT6 simultaneously detects the engine 5 speed and water temperature signals sent by the ECU1 of the engine 5, and calculates the decreasing slope K of the engine 5 speed. The clutch 7 calculates the engagement speed S according to the decreasing slope K of the engine 5 speed, and controls AMT6 to enter the gear shift synchronization state A6state=2.

[0045] In step 3, the process of the deceleration phase is as follows:

[0046] The clutch 7 dynamically detects the decreasing slope K of the engine 5 speed while slipping. When the decreasing slope K of the engine 5 speed is less than the set slope of the target engine 5 speed, the engagement speed S of the clutch 7 is accelerated; when the decreasing slope K of the engine 5 speed is greater than the set slope of the target engine 5 speed, the engagement speed S of the clutch 7 is reduced; when the decreasing slope K of the engine 5 speed is equal to the set slope of the target engine 5 speed, the engagement speed S of the clutch 7 is maintained.

[0047] In this embodiment, under the control of the slipping of the clutch 7, the decreasing slope of the engine 5 speed will be significantly higher than the natural speed reduction slope of the engine 5, so as to achieve the purpose of quickly reducing the engine 5 speed.

[0048] In this embodiment, the setting of the descending slope of the target speed of the engine 5 needs to consider many factors, such as vehicle weight, slope, acceleration, driver's required torque, engine 5 water temperature, engine 5 oil temperature and other factors. The natural deceleration slope of the engine 5 speed is different under different factors. For example, the natural deceleration slope of the engine 5 speed is faster at low temperatures. The setting of the target speed slope needs to consider the torsional vibration of the transmission system when the clutch 7 is engaged. The control method of the slip of the clutch 7 can achieve multiple power interruption times, but at the same time it will bring about a decrease in comfort. In the entire control process, the balance between power interruption and comfort should be taken into account to control the ideal clutch 7 slip speed to meet the driver's demand for shifting performance.

[0049] Step 4, after the speed of engine 5 drops rapidly through slip, when the speed difference △N1 between the speed of engine 5 and the input shaft speed of AMT6 is less than the set speed difference, AMT6 is in the gear shift synchronization state A6state=3, and clutch 7 enters the end stage of synchronization in which clutch 7 accelerates the deceleration of engine 5 by combining slip control.

[0050] In step 4, the process of the end stage is: when the speed difference ΔN1 between the engine 5 speed and the input shaft speed of the AMT 6 is less than the set speed difference, the clutch 7 displacement reaches the displacement synchronization point (ie, point C2).

[0051] Specifically, in this embodiment, when the gear shift synchronization state A6state=3, since the rotation speed of the engine 5 and the input shaft rotation speed of the AMT 6 are almost synchronized, the slip rate of the clutch 7 is close to 0, and the slip control ends.

[0052] Step five, entering the full engagement stage of clutch 7, clutch 7 quickly engages to the full engagement point (i.e., point C3) at the fastest engagement speed, and at the same time, the torque of engine 5 is returned to the driver's accelerator pedal torque through TCU2 control, so that the speed of engine 5 and the input shaft speed of AMT6 are completely synchronized, AMT6 is in the gear shift synchronization state A6state=4, and the entire upshift process is completed.

Claims

1. A method for controlling engine speed reduction during upshift synchronization based on AMT clutch engagement, characterized in that: The method proceeds as follows: Step 1: after the AMT (6) issues an upshift command, the engine (5) enters a gear shift synchronization state in a torque clearing phase, and the clutch (7) is in a completely disengaged phase; Step 2, after the gear selection of the AMT (6) is completed, the clutch (7) enters a contact phase in which the clutch (7) accelerates the engine (5) to reduce speed by combining the slip control; Step 3, after the clutch (7) is engaged and reaches the contact point, the clutch (7) enters a deceleration phase in which the clutch (7) accelerates the engine (5) by combining the slip control; Step 4, when the speed difference △N1 between the engine (5) and the input shaft speed of the AMT (6) is less than the set speed difference, the clutch (7) enters the end stage of synchronous operation in which the clutch (7) accelerates the engine (5) to reduce the speed by combining the slip control; Step 5, entering the clutch (7) full engagement stage, the clutch (7) engages to the full engagement point at the fastest engagement speed, so that the engine (5) speed and the input shaft speed of the AMT (6) are completely synchronized, and the entire upshift process is completed.

2. The method for controlling the engine speed reduction during upshifting based on the AMT clutch engagement according to claim 1, characterized in that: In step 2, the process of the contact phase is as follows: after the clutch (7) is completely disconnected from the transmission system, the clutch (7) is engaged to the contact point.

3. The method for controlling the engine speed reduction during upshifting based on the AMT clutch engagement according to claim 1, characterized in that: In step three, the process of the deceleration stage is as follows: the clutch (7) dynamically detects the decreasing slope K of the engine (5) speed while slipping; when the decreasing slope K of the engine (5) speed is less than the set slope of the target engine (5) speed, the engagement speed S of the clutch (7) is accelerated; when the decreasing slope K of the engine (5) speed is greater than the set slope of the target engine (5) speed, the engagement speed S of the clutch (7) is reduced; when the decreasing slope K of the engine (5) speed is equal to the set slope of the target engine (5) speed, the engagement speed S of the clutch (7) is maintained.

4. The method for controlling the engine speed reduction during upshifting based on the AMT clutch engagement according to claim 1, characterized in that: In step 3, after the clutch (7) is displaced to reach the contact point, the TCU (2) of the AMT (6) simultaneously detects the engine (5) speed and water temperature signals sent by the ECU (1) of the engine (5), calculates the decreasing slope K of the engine (5) speed, and the clutch (7) calculates the engagement speed S according to the decreasing slope K of the engine (5) speed.

5. The method for controlling the engine speed reduction during upshifting based on the AMT clutch engagement according to claim 1, characterized in that: In step 4, the process of the end stage is as follows: when the speed difference ΔN1 between the engine (5) speed and the input shaft speed of the AMT (6) is less than the set speed difference, the clutch (7) displacement reaches the displacement synchronization point.

6. The method for controlling the engine speed reduction during upshifting based on the AMT clutch engagement according to claim 1, characterized in that: The method adopts an upshift synchronous engine speed reduction control system based on AMT clutch engagement; The upshift synchronous engine speed reduction control system based on AMT clutch engagement comprises an ECU (1) and a TCU (2) respectively connected to a CAN line (3); the ECU (1) is connected to an engine (5) via a hard line (4); the TCU (2) is connected to an AMT (6) via a hard line (4); The engine (5) is connected to one end of the clutch (7) through a transmission system (9); the AMT (6) is connected to the other end of the clutch (7) through the transmission system (9); The clutch (7) is connected to a clutch actuator (8) via a hard wire (4), and the clutch actuator (8) is connected to a TCU (2) via a hard wire.

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