Automatic transmission control system

Abstract

To provide a control device of an automatic transmission which can learn a gear position without causing a gear block or an engine stall.SOLUTION: A control unit controls a lockup clutch into a released state on a condition that a vehicle 1 is stopped (YES in step S3) and an engine 2 has been started (YES in step S1), controls a clutch into a semi-engaged state (step S4), and executes learning control for learning a gear position of a gear change mechanism with an input shaft being rotated (step S5). The control unit performs the learning control on a further condition that a shift range being is operated to a parking range by a driver (YES in step S3). The control unit executes the learning control on a further condition that a brake operation by the driver is being performed (YES in step S3).SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a control device for an automatic transmission.

Background Art

[0002] In the control device for a transmission described in Patent Document 1, a synchronizing ring position learning unit is provided. The synchronizing ring position learning unit learns the synchronization start position (synchronizing ring position) where each sleeve shifts and contacts the synchronizing ring. This learning is performed by controlling the lock-up clutch of the torque converter to an off state and the clutch device disposed between the engine and the transmission to an on state by a hydraulic adjustment unit while the vehicle is stopped. Further, it is performed by controlling the clutch device disposed between the engine and the transmission to a semi-clutch state so that the differential rotation necessary for learning occurs.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is an automatic transmission that automatically performs a shift operation to shift gears. In this automatic transmission, it is necessary to learn the shift position (gear position). However, in the technique described in Patent Document 1, although the lock-up clutch is in an off state, learning is performed with the clutch engaged. Since the object of this learning is the synchronization start position (synchronizing ring position) where it contacts the synchronizing ring, this learning operation does not achieve a gear stage and does not involve the transmission of driving force, so it is not a problem. However, when learning the gear position that achieves a gear stage, torque transmission occurs, and there is a possibility of problems such as the vehicle starting to move or stalling.

[0005] In other words, because the clutch is engaged during learning, if learning is performed when the engine torque is unstable immediately after starting the engine, the load torque acting on the engine from the transmission via the clutch and torque converter will increase, and this load torque may cause the engine to stall. Also, if the gear position is to be learned without rotating the input shaft of the transmission, a condition may occur where a part that moves during the shift operation to the target gear comes into contact with the end face of the teeth or dog of another gear, hindering the shift operation (hereinafter referred to as "gear block").

[0006] This invention has been made in view of the circumstances described above, and aims to provide a control device for an automatic transmission that can perform gear position learning without causing gear blockage or engine stall. [Means for solving the problem]

[0007] To achieve the above objective, the present invention provides a transmission mechanism that changes the speed of rotation input from an engine to an input shaft and outputs it, a clutch provided between the engine and the transmission mechanism, and a torque converter provided between the engine and the clutch and having a lock-up clutch. The gear position consists of a shift position and a select position, and the switching component moves to a gear position where any of the gear positions, including neutral, is available. The aforementioned transmission mechanism A shift actuator that operates the shift actuator, Operating the clutch clutch A control device for an automatic transmission, comprising an actuator, For all of the aforementioned gear stages, including neutral, the gear stage setting position The system includes a control unit that performs learning control to learn, and the control unit controls the lock-up clutch to an open state and controls the clutch to a partially engaged state, and performs the learning control while the input shaft is rotating, provided that the vehicle is stopped and the engine is started. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a control device for an automatic transmission that can perform gear position learning without causing gear blockage or engine stall. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram of a vehicle equipped with a control device for an automatic transmission according to one embodiment of the present invention. [Figure 2] Figure 2 is a diagram showing the relationship between the shift position and the select position of the gear position learned by the control device of an automatic transmission according to one embodiment of the present invention. [Figure 3] Figure 3 is a timing chart showing the relationship between the clutch stroke, which is included in the execution conditions for learning control in an automatic transmission control device according to one embodiment of the present invention, and the clutch rotation speed when the clutch stroke increases. [Figure 4] Figure 4 is a flowchart showing the processing flow of learning control performed by the control device for an automatic transmission according to one embodiment of the present invention. [Modes for carrying out the invention]

[0010] A control device for an automatic transmission according to one embodiment of the present invention comprises a transmission mechanism that changes the speed of rotation input from the engine to the input shaft and outputs it, a clutch provided between the engine and the transmission mechanism, a torque converter provided between the engine and the clutch and having a lock-up clutch, and actuators that operate the transmission mechanism and the clutch, and further comprises a control unit that performs learning control to learn the gear position of the transmission mechanism, and the control unit is characterized in that, under the conditions that the vehicle is stopped and the engine is started, it controls the lock-up clutch to an open state and controls the clutch to a partially engaged state, and performs learning control with the input shaft rotating. As a result, the control device for an automatic transmission according to one embodiment of the present invention can learn the gear position without causing gear blockage or engine stall. [Examples]

[0011] Hereinafter, a vehicle equipped with an automatic transmission control device according to one embodiment of the present invention will be described with reference to the drawings.

[0012] As shown in Figure 1, the vehicle 1 is composed of an engine 2, an automatic transmission 3, drive wheels 4, and a control unit 10.

[0013] Engine 2 has multiple cylinders. In this embodiment, engine 2 is configured to perform a series of four strokes for each cylinder, consisting of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. Engine 2 is the power source for vehicle 1.

[0014] Engine 2 is equipped with an ISG (Integrated Starter Generator) 7. The ISG 7 is connected to one end of the crankshaft 21 of engine 2 via a belt 8. When power is supplied, the ISG 7 rotates, thereby rotating the crankshaft 21 and starting engine 2. The ISG 7 also rotates when power is supplied, thereby rotating the crankshaft 21 and providing motor torque for driving to engine 2. Furthermore, the ISG 7 generates electricity from the rotation of the crankshaft 21 caused by the operation of engine 2 or the deceleration energy of vehicle 1. Thus, the ISG 7 is a rotating electric machine that integrates the engine 2 starter, generator, and electric motor.

[0015] The automatic transmission 3 is installed in the power transmission path between the engine 2 and the drive wheels 4. The automatic transmission 3 includes a torque converter 30, a transmission mechanism 31, a clutch 32, a clutch actuator 33, and a shift actuator 34.

[0016] The torque converter 30 is a so-called torque converter with a lock-up clutch, having a lock-up clutch 35. The torque converter 30 is installed in the power transmission path between the engine 2 and the clutch 32 and transmits power via a working fluid.

[0017] The torque converter 30 is connected to the clutch 32 via the turbine shaft 36. The torque converter 30 amplifies the torque generated by the engine 2 and outputs it to the transmission mechanism 31 via the clutch 32.

[0018] The lock-up clutch 35 is provided within the torque converter 30 and is operable to switch between a fastening state in which the crankshaft 21 of the engine 2 and the turbine shaft 36 are integrally connected without relative rotation (hereinafter referred to as "direct connection") and an open state in which the direct connection between the crankshaft 21 and the turbine shaft 36 is released and the torque converter 30 transmits power via the working fluid.

[0019] The transmission mechanism 31 is provided in the power transmission path between the clutch 32 and the drive wheels 4 and has an input shaft 37 connected to the clutch 32 and an output shaft 38 that outputs driving force to the drive wheels 4 via the differential 5.

[0020] The transmission mechanism 31 shifts the rotation input from the engine 2 to the input shaft 37 and outputs it to the output shaft 38. The rotation output to the output shaft 38 is divided left and right by the differential 5 and transmitted to the drive wheels 4 via the drive shaft 6.

[0021] The transmission mechanism 31 is configured to be able to form a plurality of gear stages with different gear ratios by combining a plurality of gears with different numbers of teeth. The switching of the gear stage in the transmission mechanism 31 is automatically performed by the shift actuator 34. The shift actuator 34 moves a switching component for switching the gear stage to switch the gear stage. Specifically, a select position and a shift position corresponding to each gear stage of the switching component are determined, and the shift actuator 34 moves the switching component to the select position and the shift position corresponding to each gear stage. Note that this select position and shift position are gear positions and are the objects of learning in the present invention.

[0022] The clutch 32 is provided in the power transmission path between the engine 2 and the transmission mechanism 31, more specifically, between the torque converter 30 and the transmission mechanism 31. The clutch 32 has a clutch wheel disk 32a integrally rotatably connected to the turbine shaft 36 and a clutch disk 32b integrally rotatably connected to the input shaft 37.

[0023] The clutch 32 is designed to switch between a engaged state, in which power is transmitted between the turbine shaft 36 and the input shaft 37 by pressing the clutch disc 32b against the clutch wheel disc 32a, and an open state, in which power is not transmitted between the turbine shaft 36 and the input shaft 37 by releasing the clutch disc 32b from the clutch wheel disc 32a.

[0024] The clutch 32 is configured so that the clutch actuator 33 automatically switches between the engaged and disengaged states (hereinafter referred to as "clutch operation"). The transmission of driving force to the clutch 32 between the engaged and disengaged states will be described later.

[0025] The clutch actuator 33 is electrically connected to the control unit 10 and automatically performs clutch operations of the clutch 32 based on commands from the control unit 10. Clutch operation refers to changing or adjusting the state of the clutch 32, including the engaged state, the disengaged state, and the state of power transmission between them (engaged state), based on instructions from the control unit 10.

[0026] The control unit 10 is composed of a computer unit that includes a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), flash memory for storing backup data, an input port, and an output port.

[0027] The ROM of the computer unit stores various constants and maps, along with a program that allows the computer unit to function as a control unit 10. In other words, the CPU executes the program stored in the ROM using RAM as a working area, thereby allowing the computer unit to function as a control unit 10 in this embodiment.

[0028] Various sensors, including a gear position sensor 56, engine speed sensor 50, turbine speed sensor 51, clutch speed sensor 52, clutch position detection sensor 53, output speed sensor 54, and vehicle speed sensor 55, are connected to the input side of the control unit 10. In addition, information from the shift range switch 57 and brake pedal switch 58 is also connected for input.

[0029] Various control devices, such as the automatic transmission 3, clutch actuator 33, and shift actuator 34, are connected to the output side of the control unit 10.

[0030] The engine speed sensor 50 detects the engine speed based on the change in the rotation angle of the crankshaft 21 (hereinafter referred to as "crank angle").

[0031] The turbine speed sensor 51 detects the rotational speed of the turbine shaft 36 (hereinafter referred to as "turbine speed").

[0032] The clutch rotation speed sensor 52 detects the rotation speed of the input shaft 37 connected to the clutch disc 32b (hereinafter referred to as "clutch rotation speed").

[0033] The clutch position detection sensor 53 detects the state of power transmission of the clutch 32. More specifically, it detects the position of the part that changes the engagement state of the clutch 32 (hereinafter referred to as "clutch position").

[0034] The output rotation speed sensor 54 detects the rotation speed of the output shaft 38.

[0035] The vehicle speed sensor 55 detects the vehicle speed based on the rotational speed of the drive wheels 4.

[0036] The gear position sensor 56 detects the position of the switching component, which is moved by the shift actuator 34 according to each gear position. This position includes a shift position and a select position. In other words, the gear position sensor 56 can determine which gear position is achieved at the shift position and select position detected. The shift actuator 34 then moves the switching component to the learned shift position and select position to achieve the desired gear position. When learning the shift position, the value of the maximum movement in the shift direction for each gear position is determined and used as the basis for setting the range. In addition, the shift range switch 57 detects the shift range of the shift selector selected by the driver, and the brake pedal switch 58 detects when the brake pedal is pressed.

[0037] The control unit 10 switches the lock-up clutch 35 between the engaged and disengaged states. The control unit 10 controls the switching of the transmission gears in the transmission mechanism 31 and the switching of the clutch 32 according to which shift range the driver has operated the shift selector (not shown) to, as detected by the shift range switch 57. The shift ranges are the parking range (P range), the reverse range (R range), the neutral range (N range), and the forward range (D range).

[0038] The control unit 10 performs learning control to learn the gear position of the transmission mechanism 31. The control unit 10 controls the lock-up clutch 35 to an open state and the clutch 32 to a partially engaged state, and performs learning control with the input shaft 37 rotating, provided that the vehicle 1 is stopped and the engine 2 is started.

[0039] Furthermore, the control unit 10 performs learning control, with the additional condition that the driver has operated the shift range to the parking range (P range).

[0040] Furthermore, the control unit 10 performs learning control, with the additional condition that the driver has performed a brake operation. The control unit 10 updates the learned value of the shift position each time it performs learning control.

[0041] Next, the relationship between the shift position and the select position of the gear in the transmission mechanism 31 will be explained based on Figure 2.

[0042] Here, the gear positions shown in Figure 2 conceptually represent the gear positions in the transmission mechanism 31, mimicking the shift pattern in a typical manual transmission where the shift lever is operated by the driver.

[0043] The gear position sensor 56 detects the shift position and select position for each gear stage. As shown in Figure 2, the range of the shift position and the range of the select position of the switching component that achieves each gear stage are set by learning or other means. In other words, the gear positions in the transmission mechanism 31 include the 1st gear position (indicated as 1st in the figure) where the 1st gear stage is achieved, the 2nd gear position (indicated as 2nd in the figure) where the 2nd gear stage is achieved, the 3rd gear position (indicated as 3rd in the figure) where the 3rd gear stage is achieved, the 4th gear position (indicated as 4th in the figure) where the 4th gear stage is achieved, and the 5th gear position (indicated as 5st in the figure) where the 5th gear stage is achieved. Furthermore, the gear positions include a reverse position (indicated as REV in the diagram) where the reverse gear is engaged, and a neutral position (indicated as N in the diagram) where no gear is engaged.

[0044] As shown in Figure 2, the range of possible positions when each gear is set, including the neutral position, is mechanically limited, and the combination of select position and shift position that sets a gear differs depending on the gear. The target gear is set when the switching component is moved to the select position and shift position of the target gear by the drive of the shift actuator 34.

[0045] More specifically, movement in the direction of changing the shift position (hereinafter also referred to as the shift direction) is performed to move the sleeve of the target gear and engage it with that gear. Similarly, movement in the direction of changing the select position (hereinafter also referred to as the select direction) is performed to select a sleeve.

[0046] The gear position at which a gear is established when the gear is moved in the shift direction is initially set to be within a predetermined range from the position where the sleeve contacts the stopper if it is a forward gear equipped with a synchronizer mechanism, and within a predetermined range from the position where the reverse idler gear contacts the stopper if it is a reverse gear not equipped with a synchronizer mechanism. The predetermined range here is determined by considering the dimensions of the components such as the synchronizer mechanism and the detection accuracy of the gear position sensor. The position in the select direction is initially set to be within a predetermined range from the median value determined by the design values ​​based on the dimensions of the components of the transmission mechanism 31.

[0047] The control target positions for these gear stages are pre-stored in the ROM of the control unit 10. However, due to variations in component precision and aging, a discrepancy may occur between the gear stage stage position and the control target position. Therefore, gear position learning is performed to ensure that the control target position matches the actual gear stage stage position.

[0048] Next, based on Figure 3, we will explain the clutch stroke included in the execution conditions for learning control.

[0049] In Figure 3, the vertical axis represents clutch stroke, engine speed, and clutch speed, while the horizontal axis represents time. Clutch stroke is a value indicating the state of force transmission of the clutch 32 as detected by the clutch position detection sensor 53. More specifically, it is the position of the part that changes the engagement state of the clutch 32 (clutch position). Clutch stroke is expressed with the open position as 0% and the engaged position as 100%. The engine speed is maintained at a constant low speed (e.g., idle speed).

[0050] Figure 3 shows the clutch stroke changing from the release limit position (0%) to the fully engaged position (100%). At time t0, the clutch stroke is 0%, and the rotation of the turbine shaft 36 is not transmitted to the input shaft 37, so the clutch rotation speed is 0 rpm.

[0051] Subsequently, at time t1, the clutch stroke begins to increase. In other words, the operating parts begin to move in order to engage the clutch 32. Until time t2, no driving force is transmitted to the clutch disc 32b, so the clutch disc 32b (input shaft 37) remains still due to the internal resistance of the transmission mechanism 31 (friction, viscosity of lubricant, etc.). Then, at time t2, when the clutch stroke reaches the engagement start position C1, the clutch disc 32b and the clutch wheel disc 32a come into contact, the rotation of the turbine shaft 36 is transmitted to the input shaft 37, and the clutch rotation speed begins to increase.

[0052] Subsequently, at time t3, the clutch stroke reaches a semi-engaged position C2 that is a predetermined value greater than the engagement start position C1, and the clutch 32 enters a semi-engaged state, increasing the transmitted driving torque. In balance with the internal resistance of the transmission mechanism 31, the clutch rotation speed increases further.

[0053] Subsequently, at time t4, the clutch stroke increases further, and the clutch transmission torque becomes even greater, exceeding the internal resistance of the transmission mechanism 31, so that the clutch rotation speed becomes equal to the engine rotation speed.

[0054] Subsequently, at time t5, the clutch stroke reaches 100%, the clutch 32 becomes fully engaged, and the clutch rotation speed becomes the same as the engine rotation speed. For learning in this invention, the range from the engagement start position C1 to the half-engaged position C2 is used. That is, the range from the engagement start position C1 to the half-engaged position C2 which is a predetermined value greater than the engagement start position C1, and the range of clutch transmission torque which is about the same as the internal resistance of the transmission mechanism 31 is used.

[0055] Next, referring to Figure 4, the processing flow of the learning control performed by the control unit 10 in this embodiment will be described. The learning control shown in Figure 4 is repeatedly performed at predetermined time intervals.

[0056] As shown in Figure 4, the control unit 10 determines whether or not the engine 2 is running (step S1), and if the engine 2 is not running, it terminates the current operation.

[0057] If the engine 2 is started in step S1, the control unit 10 determines whether the gear position has not been learned (step S2). If the gear position has not been learned (learned), the control unit 10 terminates the current operation.

[0058] If the gear position is not learned in step S2, the control unit 10 determines whether the shift range is in the P range and whether the brake stroke value or master cylinder pressure is above a predetermined value (step S3). If the shift range is not in the P range, or if the brake stroke value or master cylinder pressure is below the predetermined value, it waits for the shift range to reach the P range and the brake stroke value or master cylinder pressure to reach the predetermined value. The determination that the shift range is in the P range is made to confirm that the vehicle 1 is stopped and that the driver has no intention of starting. The brake operation by the driver is also made to confirm that the driver is in a state where they can deal with the unintended movement of the vehicle 1.

[0059] In step S3, if the shift range is in the P range and the brake stroke value or master cylinder pressure is greater than or equal to a predetermined value, the control unit 10 sets the clutch position to the semi-engaged position (step S4). Here, the clutch position is controlled so that the clutch stroke is at the semi-engaged position C2 in the graph of Figure 3. Also, the lock-up clutch 35 is controlled to the open state.

[0060] Next, the control unit 10 starts learning the gear position (step S5), and ends the operation after the learning is complete. Gear position learning involves moving the switching component, which is actually moved according to each gear stage, to the position corresponding to each gear stage using the shift actuator 34, detecting that position with the gear position sensor 56, and learning the detected value.

[0061] As described above, the control device for the automatic transmission according to this embodiment includes a control unit 10 that performs learning control to learn the gear position of the transmission mechanism 31. The control unit 10 controls the lock-up clutch 35 to an open state and the clutch 32 to a partially engaged state, and performs learning control while the input shaft 37 is rotating, provided that the vehicle 1 is stopped and the engine 2 is started.

[0062] As a result, the clutch 32 is in a semi-engaged state during learning, allowing the input shaft 37 to rotate appropriately and preventing the occurrence of gear blockage. Furthermore, the torque transmitted to the transmission mechanism 31 is not excessive, which suppresses the movement and shock of the vehicle 1 when a gear is achieved. In addition, it is possible to suppress the rotational speed of the input shaft 37 from becoming unnecessarily large, which prevents the transmission mechanism 31 from being unable to start shifting gears due to suppressed gear rotational speed, thus preventing the occurrence of gear blockage.

[0063] Furthermore, since the clutch 32 is in a partially engaged state during learning, even when learning is performed when the engine torque is small and unstable immediately after starting the engine 2, the load torque acting on the engine 2 from the transmission mechanism 31 via the clutch 32 and torque converter 30 can be reduced, thereby preventing engine stall.

[0064] As a result, gear position learning can be performed without causing gear blockages or engine stalls.

[0065] Furthermore, in the control device for the automatic transmission according to this embodiment, the control unit 10 performs learning control with the additional condition that the driver has operated the shift range to the parking range (P range).

[0066] As a result, engine torque is not input from the transmission mechanism 31 to the output shaft 38 while the gear position is being learned, thus preventing the vehicle 1 from moving.

[0067] Furthermore, in the control device for the automatic transmission according to this embodiment, the control unit 10 performs learning control with the additional condition that the driver is performing a brake operation.

[0068] As a result, while the gear position is being learned, vehicle 1 is kept under braking, thus preventing vehicle 1 from moving.

[0069] While embodiments of the present invention have been disclosed, it will be apparent to those skilled in the art that modifications can be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims. [Explanation of Symbols]

[0070] 1 vehicle 2 engines 3 Automatic transmission 10 Control Unit 30 Torque Converter 31. Transmission 32 Clutch 34. Shift actuator (actuator) 35 Lock-up clutch 37 Input axes

Claims

1. A control device for an automatic transmission comprising: a transmission mechanism that changes the speed of rotation input from an engine to an input shaft and outputs it; a clutch provided between the engine and the transmission mechanism; a torque converter provided between the engine and the clutch and having a lock-up clutch; a shift actuator that operates the transmission mechanism so that a switching component moves to a gear position where any of the transmission gear positions, including neutral, is established, among gear positions consisting of a shift position and a select position; and a clutch actuator that operates the clutch, The system includes a control unit that performs learning control to learn the gear position for all gear stages, including the neutral position, The control unit, A control device for an automatic transmission, characterized in that, provided the vehicle is stopped and the engine is running, the lock-up clutch is controlled to be in an open state, the clutch is controlled to be in a partially engaged state, and the learning control is performed while the input shaft is rotating.

2. The control device for an automatic transmission according to claim 1, characterized in that the control unit performs the learning control on the condition that the shift range is operated to the parking range by the driver.

3. The control device for an automatic transmission according to claim 1 or 2, characterized in that the control unit performs the learning control on the condition that the driver is performing a brake operation.

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