A method and system for creep launch control of a hybrid at transmission

Abstract

The application discloses a kind of hybrid AT transmission's creeping start control method and system, by obtaining vehicle message signal, when entering creeping state control, activate creeping mode, enter clutch filling stage;After filling is completed, enter build speed stage;Judge creeping vehicle speed target completion, enter uniform speed stage;After detecting brake pressure rises and does not exceed the threshold value of creeping state exit, enter brake stage;Brake pressure rises to the threshold value of creeping state exit after, exit creeping mode, enter parking stage;When entering start state control, activate start mode, enter clutch filling stage;After filling is completed, enter build speed stage;Judge transmission start clutch slip is less than threshold value, enter combination stage;After judging transmission start clutch slip 0, exit start mode, enter travel stage.In control process, need with vehicle constantly carries out message information exchange, and sends control instruction to transmission internal hydraulic system, carries out control.

Description

Technical Field

[0001] The present invention belongs to the technical field of transmission starting control, and relates to a creep starting control method and system for a hybrid automatic transmission. Background Art

[0002] Hybrid technology, currently a key development direction for the automotive industry, utilizes both an engine and an electric motor as the vehicle's power source, achieving the goals of reducing fuel consumption and increasing power. However, a mature, unified solution for controlling hybrid automatic transmissions throughout the entire starting phase has yet to be proposed. Current creep control primarily relies on obtaining vehicle speed information and then determining creep torque through a table lookup to control vehicle creep. This approach, however, fails to synchronize creep start judgment and adjustment with real-time vehicle information. Summary of the Invention

[0003] The purpose of the present invention is to solve the problem in the prior art of how to determine whether to enter a creep state or switch to a start state based on vehicle-related information, and to provide a creep start control method and system for a hybrid AT transmission.

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

[0005] A creep start control method for a hybrid automatic transmission comprises the following steps:

[0006] Obtain vehicle message signals to determine whether to enter creep state control or start state control;

[0007] If the vehicle enters creep state control, the TCU activates creep mode and enters the clutch filling phase;

[0008] After the clutch is filled, it enters the speed building phase;

[0009] The TCU determines that the creeping speed target has been achieved and enters the constant speed stage;

[0010] After the TCU detects that the brake pressure has increased and has not exceeded the creep state exit threshold, it enters the braking phase;

[0011] When the brake pressure rises to the creep state exit threshold, the creep mode is exited and the parking phase is entered;

[0012] If the start state control is entered, the TCU activates the start mode and enters the clutch filling stage;

[0013] After the clutch is filled, it enters the speed building phase;

[0014] The TCU determines that the transmission starting clutch slip is less than the threshold and enters the engagement stage;

[0015] After the TCU determines that the transmission starting clutch slip is 0, it exits the starting mode and enters the driving stage.

[0016] A further improvement of the present invention is:

[0017] When entering the creep state control, the TCU activates the creep mode and enters the clutch filling stage, the specific steps are: the TCU controls the transmission starting clutch to fill, and sends the actual state of the transmission, the starting clutch state and the transmission power chain state as creep mode to the HCU; after receiving the state information, the HCU sends the vehicle mode as creep mode.

[0018] In the creep control state, after the clutch filling is completed, the speed building phase begins. The specific steps are as follows:

[0019] The TCU sets the creep speed target value and sends the creep idle target value to the HCU, where the creep idle target value is equal to the creep speed target value;

[0020] The transmission starting clutch increases torque, which is adjusted based on the deviation between the creep idle target value and the motor speed;

[0021] After receiving the creep idle target value, the HCU arbitrates the idle speed and controls the motor to enter the speed mode, uses the target torque of the creep clutch as the feedforward torque for speed control, and sends the arbitrated idle speed to the TCU.

[0022] The TCU determines that the creep speed target is achieved and enters the constant speed stage. The TCU presses the transmission starting clutch, and the HCU controls the speed according to the creep clutch target torque.

[0023] When entering the braking phase, the TCU performs open-loop control of the transmission starting clutch torque according to the brake pressure, and the HCU performs speed control according to the creep clutch target torque.

[0024] The starting state control is entered, and the TCU activates the starting mode. When entering the clutch filling stage, the TCU controls the transmission starting clutch to fill, sends the actual state of the transmission, the state of the transmission clutch, and the state of the transmission power chain as the starting mode to the HCU, and monitors the degree of engine overrun. When the degree of overrun exceeds the threshold, the torque limit value is sent to the HCU; after receiving the state information, the HCU sends the vehicle mode as the starting mode.

[0025] In the starting control state, after the clutch filling is completed and the vehicle enters the speed-building phase, the TCU adjusts the increase in the transmission clutch torque according to the input shaft speed, and sends the actual torque of the transmission clutch to the HCU in real time. The creep clutch target torque sent to the HCU is always 0 Nm; the HCU responds to the torque limit value sent by the TCU.

[0026] When entering the engagement phase, the TCU cancels the torque limit and tightens the transmission starting clutch; the HCU continues to respond to the torque limit value sent by the TCU.

[0027] The vehicle message signal includes throttle, brake, rotation speed and vehicle speed.

[0028] A creep start control system for a hybrid automatic transmission includes the following modules:

[0029] An HCU control unit, the HCU control unit is used to send throttle, brake, speed and vehicle mode signals to the TCU control unit;

[0030] A TCU control unit, the TCU control unit is used to send a power train state, a start clutch state, an electronic pump speed, an input shaft speed and a requested torque signal to the HCU control unit;

[0031] An EMS control unit, the EMS control unit is used to send an engine speed signal to the TCU control unit;

[0032] The MCU control unit is used to send the motor speed signal to the TCU control unit;

[0033] The transmission unit receives the clutch control signal and the solenoid valve control signal sent by the TCU.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] This invention proposes a method for controlling the creep start of a hybrid automatic transmission. This method receives messages from relevant nodes in the vehicle network and uses vehicle-related information to determine whether to enter a creep state or switch to a start state. Once the creep state is determined to have entered, control is performed according to the creep state control method. Once the start state is determined to have entered, control is performed according to the start state control method. During this control process, the system continuously exchanges messages with the vehicle and sends control commands to the transmission's internal hydraulic system for control. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1This is a flow chart of a creep start control method for a hybrid AT transmission of the present invention;

[0038] Figure 2 This is a schematic diagram of the control system module in the present invention;

[0039] Figure 3 A schematic diagram of the switching between various states of a hybrid AT transmission;

[0040] Figure 4 This is a schematic diagram of the EV creep state control process;

[0041] Figure 5 Schematic diagram of the EV starting state control process. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0044] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0045] In the description of the embodiments of the present invention, it should be noted that if the terms "upper," "lower," "horizontal," "inner," etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the inventive product is typically placed when in use. These terms are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first," "second," etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0046] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0047] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0048] The present invention's creep start control for a hybrid automatic transmission requires receiving messages from relevant nodes in the vehicle network. Using vehicle-related information, the system determines whether to enter creep mode or switch to start mode. Once the creep mode is determined to have entered, control is performed according to the creep mode control method. Once the start mode is determined to have entered, control is performed according to the start mode control method. During this control process, the system continuously exchanges messages with the vehicle and sends control commands to the transmission's internal hydraulic system for control.

[0049] The present invention is described in further detail below with reference to the accompanying drawings:

[0050] See also Figure 1 , is a flow chart of a creep start control method for a hybrid AT transmission in the present invention, comprising the following steps:

[0051] Obtain vehicle message signals to determine whether to enter creep state control or start state control;

[0052] If the vehicle enters creep state control, the TCU activates creep mode and enters the clutch filling phase;

[0053] After the clutch is filled, it enters the speed building phase;

[0054] The TCU determines that the creeping speed target has been achieved and enters the constant speed stage;

[0055] After the TCU detects that the brake pressure has increased and has not exceeded the creep state exit threshold, it enters the braking phase;

[0056] When the brake pressure rises to the creep state exit threshold, the creep mode is exited and the parking phase is entered;

[0057] If the start state control is entered, the TCU activates the start mode and enters the clutch filling stage;

[0058] After the clutch is filled, it enters the speed building phase;

[0059] The TCU determines that the transmission starting clutch slip is less than the threshold and enters the engagement stage;

[0060] After the TCU determines that the transmission starting clutch slip is close to 0rpm, it exits the starting mode and enters the driving stage.

[0061] See also Figure 2 , is a schematic diagram of the control system module in the present invention, which specifically includes the following modules:

[0062] An HCU control unit, the HCU control unit is used to send throttle, brake, speed and vehicle mode signals to the TCU control unit;

[0063] A TCU control unit, the TCU control unit is used to send a power train state, a start clutch state, an electronic pump speed, an input shaft speed and a requested torque signal to the HCU control unit;

[0064] An EMS control unit, the EMS control unit is used to send an engine speed signal to the TCU control unit;

[0065] The MCU control unit is used to send the motor speed signal to the TCU control unit;

[0066] The transmission unit receives the clutch control signal and the solenoid valve control signal sent by the TCU.

[0067] See also Figure 3 , is a schematic diagram of the switching between the various states of the hybrid AT transmission. In the process of the vehicle going from parking to normal driving state, the hybrid AT transmission is divided into the following states accordingly: parking state, creeping state, starting state, and driving state. The TCU is based on the received signal: (1) if the brake is less than the threshold, the throttle is less than the threshold, and the input shaft speed is greater than the threshold, then the vehicle enters the creeping state from the parking state; (2) if the brake is less than the threshold, the throttle is greater than the threshold, and the input shaft speed is greater than the threshold, then the vehicle enters the starting state from the creeping state; (3) if the vehicle speed is greater than the threshold, then the vehicle enters the driving state from the starting state; (4) if the vehicle speed is less than the threshold, then the vehicle enters the starting state from the driving state; (5) if the throttle is less than the threshold and the input shaft speed is less than the threshold, then the vehicle enters the creeping state from the starting state; (6) if the brake is less than the threshold and the input shaft speed is less than the threshold, then the vehicle enters the parking state from the creeping state; (7) if the brake is less than the threshold, the throttle is greater than the threshold, and the input shaft speed is greater than the threshold, then the vehicle enters the starting state from the parking state; (8) if the throttle is less than the threshold, the brake is greater than the threshold, and the input shaft speed is greater than the threshold, then the vehicle enters the parking state from the starting state.

[0068] The pure electric creep state control method of the present invention, i.e., when the EOP is normal and the clutch starts to engage after reaching the Creep speed, the creep start control of the hybrid AT transmission is specifically implemented by the following steps:

[0069] First, the system determines whether to enter creep mode or start mode by receiving vehicle message signals, including throttle, brake, speed, and vehicle speed.

[0070] If the TCU enters creep state control based on comprehensive judgment of the vehicle message signal, the control steps are as follows:

[0071] Step 1: TCU activates creep mode and enters (1) filling phase.

[0072] Step 1.1, the TCU controls the transmission starting clutch to fill, and at the same time sends the actual state of the transmission (driving mode), the starting clutch state and the transmission power train state as Creep to the HCU.

[0073] Step 1.2: After receiving the above status information, the HCU sends the vehicle mode as Creep.

[0074] Step 2: The TCU determines that the transmission starting clutch filling is completed and enters the (2) speed building phase.

[0075] In step 2.1, the TCU sets the creep speed target value and sends the creep idle target value to the HCU (the idle target must be equal to the vehicle speed target). At the same time, the transmission starting clutch increases the torque (PID real-time adjustment is performed based on the deviation between the idle target and the motor speed after HCU arbitration).

[0076] In step 2.2, after receiving the creep idle target, the HCU arbitrates the idle speed and controls the motor to enter the speed mode. At this time, the creep clutch target torque is used as the feedforward torque of the speed control PID algorithm. The arbitrated idle speed needs to be sent to the TCU.

[0077] Step 3: The TCU determines that the creeping speed target is achieved and enters the (3) uniform speed stage.

[0078] Step 3.1, the TCU presses the transmission starting clutch.

[0079] In step 3.2, the HCU continues to control the speed by referring to the creep clutch target torque.

[0080] Step 4: After the TCU detects that the brake pressure has risen to a certain level and has not exceeded the creep exit threshold, it enters the (4) light braking stage.

[0081] In step 4.1, the TCU performs open-loop control of the transmission starting clutch torque based on the brake pressure (control of a relatively low vehicle speed such as 3 km / h is achieved by lightly pressing the brake, at which time the transmission starting clutch is in a slipping state).

[0082] In step 4.2, the HCU continues to control the speed by referring to the creep clutch target torque.

[0083] Step 5: The TCU determines that the brake pressure rises to the creep mode exit threshold and then exits the creep mode and enters the (5) parking stage.

[0084] If the TCU enters the starting state control based on the comprehensive judgment of the vehicle message signal, the control steps are as follows:

[0085] Step 1: The TCU activates the start mode and enters the (1) filling phase.

[0086] In step 1.1, the TCU controls the transmission's starting clutch to fill and simultaneously sends the actual transmission status (driving mode), the transmission clutch status, and the transmission powertrain status (Launch) to the HCU. Throughout the process, the TCU monitors the engine's overrun level and sends the torque limit value to the HCU if the overrun exceeds a certain threshold.

[0087] Step 1.2: After receiving the above status information, the HCU sends the vehicle mode to Launch. If there is a torque limit request, it responds to the torque limit value sent by the TCU.

[0088] Step 2: The TCU determines that the transmission starting clutch filling is completed and enters the (2) speed building phase.

[0089] In step 2.1, the TCU dynamically adjusts the increase in transmission clutch torque based on the estimated input shaft speed. During this process, the actual transmission clutch torque is sent to the HCU in real time. At the same time, the creep clutch target torque sent to the HCU is always 0 Nm (this is to prevent the feedforward torque of the motor speed control PID algorithm from participating in the regulation).

[0090] Step 2.2: The HCU continues to respond to the torque limit value sent by the TCU.

[0091] Step 3: The TCU determines that the transmission starting clutch slip is less than a certain value and enters the (3) engagement stage.

[0092] Step 3.1: The TCU cancels the torque limit and tightens the transmission starting clutch.

[0093] Step 3.2: The HCU continues to respond to the torque limit value sent by the TCU.

[0094] Step 4: After the TCU determines that the transmission starting clutch slip is close to 0 rpm, it exits the starting mode and enters the (4) driving stage.

[0095] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A creep start control method for a hybrid automatic transmission, characterized in that: The following steps are involved: Obtain vehicle message signals to determine whether to enter creep state control or start state control; If the vehicle enters creep state control, the TCU activates creep mode and enters the clutch filling phase; After the clutch is filled, it enters the speed building phase; the specific steps are as follows: The TCU sets the creep speed target value and sends the creep idle target value to the HCU, where the creep idle target value is equal to the creep speed target value; The transmission starting clutch increases torque, which is adjusted based on the deviation between the creep idle target value and the motor speed; After receiving the creep idle target value, the HCU arbitrates the idle speed and controls the motor to enter the speed mode. The target torque of the creep clutch is used as the feedforward torque for speed control, and the arbitrated idle speed is sent to the TCU. The TCU determines that the creeping speed target has been achieved and enters the constant speed stage; After the TCU detects that the brake pressure has increased and has not exceeded the creep state exit threshold, it enters the braking phase; When the brake pressure rises to the creep state exit threshold, the creep mode is exited and the parking phase is entered; If the start state control is entered, the TCU activates the start mode and enters the clutch filling stage; After the clutch is filled, it enters the speed building phase; In the aforementioned starting control state, after the clutch filling is completed and the acceleration phase begins, the TCU adjusts the increase in the transmission clutch torque according to the input shaft speed and sends the actual transmission clutch torque to the HCU in real time. The creep clutch target torque sent to the HCU is always 0 Nm; the HCU responds to the torque limit value sent by the TCU. The TCU determines that the transmission starting clutch slip is less than the threshold and enters the engagement stage; After the TCU determines that the transmission starting clutch slip is 0, it exits the starting mode and enters the driving stage.

2. The creep start control method of a hybrid automatic transmission according to claim 1, characterized in that: When entering the creep state control, the TCU activates the creep mode and enters the clutch filling stage, the specific steps are: the TCU controls the transmission starting clutch to fill, and sends the actual state of the transmission, the starting clutch state and the transmission power chain state as creep mode to the HCU; after receiving the state information, the HCU sends the vehicle mode as creep mode.

3. The creep start control method of a hybrid automatic transmission according to claim 1, characterized in that: The TCU determines that the creep speed target is achieved and enters the constant speed stage. The TCU presses the transmission starting clutch, and the HCU controls the speed according to the creep clutch target torque.

4. The creep start control method of a hybrid automatic transmission according to claim 1, characterized in that: When entering the braking phase, the TCU performs open-loop control of the transmission starting clutch torque according to the brake pressure, and the HCU performs speed control according to the creep clutch target torque.

5. The creep start control method of a hybrid automatic transmission according to claim 1, characterized in that: The starting state control is entered, and the TCU activates the starting mode. When entering the clutch filling stage, the TCU controls the transmission starting clutch to fill, sends the actual state of the transmission, the state of the transmission clutch, and the state of the transmission power chain as the starting mode to the HCU, and monitors the degree of engine overrun. When the degree of overrun exceeds the threshold, the torque limit value is sent to the HCU; after receiving the state information, the HCU sends the vehicle mode as the starting mode.

6. The creep start control method of a hybrid automatic transmission according to claim 1, characterized in that: When entering the engagement phase, the TCU cancels the torque limit and tightens the transmission starting clutch; the HCU continues to respond to the torque limit value sent by the TCU.

7. The creep start control method of a hybrid automatic transmission according to claim 1, characterized in that: The vehicle message signal includes throttle, brake, rotation speed and vehicle speed.

8. A creep start control system for a hybrid automatic transmission based on the method according to any one of claims 1 to 7, characterized in that: Includes the following modules: An HCU control unit, the HCU control unit is used to send throttle, brake, speed and vehicle mode signals to the TCU control unit; A TCU control unit, the TCU control unit is used to send a power train state, a start clutch state, an electronic pump speed, an input shaft speed and a requested torque signal to the HCU control unit; An EMS control unit, the EMS control unit is used to send an engine speed signal to the TCU control unit; The MCU control unit is used to send the motor speed signal to the TCU control unit; The transmission unit receives the clutch control signal and the solenoid valve control signal sent by the TCU.

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