An amt economy cruise control method and system

Abstract

The application discloses an AMT economic coasting control method and system, and relates to the technical field of vehicle transmission control, which comprises the following steps: obtaining vehicle operating state parameters to determine coasting entry conditions, and outputting an economic coasting condition satisfaction symbol when all the conditions are satisfied; obtaining the operating state of a mechanical automatic transmission, determining whether the state maintenance calibration condition is satisfied, and executing delay control, and activating the economic coasting state when the target delay time is reached; executing the neutral coasting process according to the operating state of the transmission, completing the decoupling of the transmission system, and entering the economic coasting; monitoring the exit trigger condition in the coasting period, and canceling the state when the condition is satisfied, calculating the target combination gear position, and restoring the on-gear operating state. The application prevents high-frequency switching of the system through multi-dimensional determination and delay mechanism, applies time alignment and speed regulation to reduce mechanical resistance during decoupling, and calculates the combination gear position based on the reference vehicle speed and synchronizes the speed during exit, so that the longitudinal impact of the vehicle during the recombination of the clutch is reduced.

Description

Technical Field

[0001] This application relates to the field of vehicle transmission control technology, and in particular to an AMT (Automated Manual Transmission) economic coasting control method and system. Background Technology

[0002] Automatic manual transmissions (AMTs) are widely used in commercial and passenger vehicles, and coasting is a crucial function for reducing overall fuel consumption. This function automatically shifts to neutral under specific operating conditions, disconnecting the engine from the transmission system and using vehicle inertia to maintain motion. Existing AMT coasting control strategies often rely on single parameter thresholds for logical judgments. In complex real-world road conditions, sensor sampling noise or transient adjustments to the driver's accelerator pedal can easily interfere with the controller's logic, leading to frequent switching between coasting and in-gear states. Frequent system intervention not only increases wear on the gear-shifting actuators but also affects the stability of the underlying control state machine.

[0003] During the decoupling execution phase of the transmission system entering coasting, accurate torque control is a prerequisite for successfully disengaging into neutral. Current technologies typically rely on direct reading of bus data for torque clearing judgments. However, due to communication delays between controller nodes, there is often a time lag between the asynchronously transmitted torque message and the local real-time status. This data misalignment makes it difficult for the system to accurately capture the true torque transmitted by the clutch. Forcibly disengaging the gear while residual torque is present increases the mechanical friction resistance between the shift fork and the synchronizer, and may even cause jamming.

[0004] Furthermore, when the vehicle exits coasting due to braking or acceleration, the transmission needs to recalculate the target gear and engage the clutch. Existing gear recovery strategies are prone to calculation errors in the target gear ratio at extremely low speeds and lack a rigorous timing verification mechanism to confirm the authenticity of the coasting exit conditions. With insufficient smoothness in the underlying command coverage, the actual engine speed and the clutch input shaft speed cannot achieve precise matching in a short time. The prolonged speed synchronization time results in excessive slippage work during clutch engagement, causing significant longitudinal shocks in the transmission system and reducing vehicle ride smoothness. Summary of the Invention

[0005] The purpose of this invention is to provide an AMT (Automated Manual Transmission) economic coasting control method and system, which at least solves one of the technical problems of existing mechanical automatic transmissions when performing economic coasting: high-frequency switching due to transient parameter fluctuations; mechanical interference caused by inaccurate torque judgment due to underlying communication delays when decoupling the transmission system; and long speed synchronization time and longitudinal impact of the transmission system when exiting the coasting gear and restoring the gear, which reduces the ride smoothness of the vehicle.

[0006] This invention provides the following solution:

[0007] According to one aspect of the present invention, an AMT (Automated Manual Transmission) economic coasting control method is provided, comprising the following steps:

[0008] The vehicle's operating status parameters are acquired and the conditions for coasting are determined. When the acquired real-time parameters meet all the preset judgment conditions, an economic coasting condition is satisfied flag is output.

[0009] After outputting the flag indicating that the economic coasting condition is met, the operating status of the mechanical automatic transmission is obtained, and the preset target delay time is calculated in combination with the vehicle mass and the current gear. Then, it is determined whether the operating status of the mechanical automatic transmission meets the status maintenance verification condition and delay control is executed. When the duration for which the status maintenance verification condition is met reaches the target delay time, the economic coasting state is activated and an economic coasting state activation flag is sent.

[0010] After obtaining the economic coasting state activation flag, the neutral coasting process is executed according to the operating status of the mechanical automatic transmission, completing the decoupling of the transmission system and finally entering economic coasting;

[0011] During the coasting cycle, the system monitors the exit trigger conditions. When the exit trigger conditions are met, the coasting state is canceled, the target gear is calculated, and the target gear is engaged to restore the mechanical automatic transmission to its in-gear operation.

[0012] Furthermore, when determining the conditions for coasting entry, the longitudinal driving speed, engine speed, engine coolant temperature, service brake pedal signal, throttle opening, driver-requested torque, auxiliary braking requested torque and actual torque, vehicle turning radius, vehicle gradient, and vehicle acceleration parameters are comprehensively considered.

[0013] Furthermore, determining whether the operating state of the mechanical automatic transmission meets the state maintenance verification conditions and performing delay control includes: acquiring the vehicle mass and current gear, using them as dual-input indexes to perform a two-dimensional lookup table operation to pre-obtain the target delay time; constructing the state maintenance verification conditions based on whether the mechanical automatic transmission is in gear or in shift execution state, combined with the economic coasting condition satisfaction flag; acquiring the vehicle mass and current gear as dual-input indexes to perform a two-dimensional lookup table operation to obtain the target delay time; and using an internal accumulator timer to perform cyclic detection within the control clock cycle, forcibly clearing the accumulator timer if the state maintenance verification conditions fail to change.

[0014] Furthermore, the neutral coasting process, based on the operating status of the mechanical automatic transmission, includes: for coasting triggered in gear, a torque clearing process is performed, using a time alignment algorithm to synchronize and pair the bus torque message with the locally high-frequency estimated clutch transmission torque to determine torque clearing completion; subsequently, a speed adjustment process is initiated, calculating the target input shaft speed based on the mechanical speed ratio of the current transmission output shaft speed and the gear before disengaging to determine speed adjustment completion; finally, the completion of the neutral operation is confirmed by collecting the absolute deviation between the actual position value and the center position coordinate of the shift displacement sensor, combined with displacement installation and manufacturing tolerance thresholds and preset physical limit braking time limits. For coasting triggered in a shift execution state, the torque clearing process is skipped, and the speed adjustment process is initiated directly.

[0015] Furthermore, the background monitoring exit trigger conditions include: introducing a timestamp-based zero-order hold logic to align and sample asynchronous data, and obtaining aligned brake pedal state, throttle opening, real-time vehicle speed, vehicle slope, and turning radius data; and using a sliding time window continuous verification mechanism to determine whether the exit trigger conditions are met.

[0016] Furthermore, canceling the economic coasting state and calculating the target gear engagement includes: resetting the internal economic coasting state activation flag and related control state machine registers to zero; selecting the larger of the current real-time vehicle speed and the set ultra-low speed protection threshold as the calculation reference speed for zero-reduction protection; and deriving the target transmission ratio in reverse based on the target engine speed, wheel rolling radius, drive axle main reduction ratio, and calculation reference speed, and traversing the available forward gear set to find the gear corresponding to the minimum absolute difference in the gear ratio as the target gear engagement.

[0017] Furthermore, engaging the target gear and restoring the mechanical automatic transmission to its in-gear operating state includes: calculating the target speed of the clutch input shaft based on the target gear ratio; issuing a command to the engine control module to execute active speed-up control; and issuing a clutch engagement command when the absolute value of the difference between the actual engine speed and the input shaft speed is stable within the set speed synchronization tolerance threshold.

[0018] The control method of this invention uses multi-dimensional entry condition judgment and state maintenance verification delay control, combined with two-dimensional lookup table operation to obtain the target delay time, to avoid false triggering of the coasting state caused by sensor sampling noise and transient driving interference, and to prevent frequent switching between coasting and in-gear states. The decoupling process of the transmission system is divided into torque clearing and speed adjustment stages. A time alignment algorithm is applied to process asynchronous bus messages to reduce torque calculation errors caused by underlying communication delays. By calculating the kinematic speed matching relationship between the input and output shafts of the transmission, the mechanical resistance when shifting to neutral is reduced. In the coasting exit stage, a zero-order hold and a sliding time window are used to align and verify the data, improving the timing synchronization and reliability of the monitoring data. A calculation benchmark vehicle speed for zero-reduction protection is set to calculate the target gear ratio and deduce the target engaged gear in reverse. Combined with active engine acceleration control, the slippage work and longitudinal impact of the vehicle during clutch engagement are reduced.

[0019] According to a second aspect of the present invention, an AMT (Automated Manual Transmission) economic coasting control system is provided, comprising:

[0020] The condition determination module is used to acquire vehicle operating status parameters and determine the conditions for coasting. When the acquired real-time parameters meet all preset judgment conditions, it outputs an economic coasting condition satisfaction flag.

[0021] The delay control module is used to obtain the operating status of the mechanical automatic transmission after outputting the economic coasting condition satisfaction flag, and obtain a preset target delay time, determine whether the operating status of the mechanical automatic transmission satisfies the state maintenance verification condition and perform delay control, and when the duration for which the state maintenance verification condition is continuously satisfied reaches the target delay time, activate the economic coasting state and send the economic coasting state activation flag.

[0022] The decoupling execution module is used to execute the neutral coasting process according to the operating state of the mechanical automatic transmission after obtaining the economic coasting state activation flag, thereby completing the decoupling of the transmission system and finally entering economic coasting.

[0023] The state recovery module is used to monitor the exit trigger condition in the background during the economic coasting cycle. When the exit trigger condition is detected, the economic coasting state is canceled, the target gear is calculated, and the target gear is engaged to restore the mechanical automatic transmission to the in-gear operation state.

[0024] The above solution achieves the following beneficial technical effects:

[0025] This application establishes a multi-dimensional coasting entry condition determination mechanism and introduces a target delay time obtained by combining the vehicle mass and the current gear two-dimensional lookup table. Combined with state maintenance verification and forced zeroing logic of the accumulator timer, it can filter out sensor sampling noise and interference caused by driver transient operation, avoid high-frequency switching oscillation of the transmission between coasting and in-gear states, and ensure the reliability of the system determination.

[0026] This application explicitly divides the decoupling action into torque clearing and speed adjustment stages, and uses a time alignment algorithm to synchronize the bus torque message and the locally estimated torque, reducing torque calculation errors caused by asynchronous underlying communication. Simultaneously, it calculates the target input shaft speed based on the transmission output shaft speed, enabling the neutral shift operation to be performed within a threshold range where both torque and speed meet matching conditions, thus reducing mechanical friction during actuator operation.

[0027] This application uses a timestamp-based zero-order hold and a sliding time window to verify the exit trigger condition, and introduces a reference vehicle speed to prevent zero-removal protection during the gear selection stage. The optimal target engagement gear is obtained by back-engineering the target transmission ratio and then the engine is actively accelerated by issuing commands. This ensures that the actual engine speed and the input shaft speed are matched within the synchronization tolerance threshold, reducing the slippage work and longitudinal impact of the vehicle during the clutch re-engagement stage. Attached Figure Description

[0028] Figure 1 This is a general flowchart of the AMT economic coasting control method provided in the embodiments of the present invention;

[0029] Figure 2 This is a flowchart illustrating the specific control logic of the AMT (Automated Manual Transmission) economic coasting control provided in this embodiment of the invention.

[0030] Figure 3 This is a module architecture diagram of the AMT economic coasting control system provided in an embodiment of the present invention. Detailed Implementation

[0031] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] See attached document Figure 1 This invention provides an AMT (Automated Manual Transmission) economic coasting control method, comprising the following steps:

[0033] S10, acquire vehicle operating status parameters and determine the conditions for coasting entry;

[0034] S20 identifies the operating status of the mechanical automatic transmission and performs delay control;

[0035] S30 executes the neutral coasting process according to the operating status of the mechanical automatic transmission;

[0036] S40 monitors the triggering conditions and performs glide exit and state recovery.

[0037] This control method relies on the vehicle's electronic control network and chassis transmission hardware. The shift control unit acquires real-time vehicle operating status data through the vehicle controller's local area network. It communicates with the engine control module to obtain engine speed, driver-requested torque, and engine coolant temperature. It also communicates with the anti-lock braking system (ABS) or electronic stability control system (ESC) to obtain vehicle speed, acceleration, turning radius, and gradient. Furthermore, the shift control unit uses onboard sensors to acquire throttle opening, brake pedal status, requested auxiliary braking torque, and actual auxiliary braking torque. At the control execution end, the shift control unit sends control requests to the clutch, shift actuator, and engine control module, completing the decoupling and engagement of the transmission system.

[0038] In step S10, the shift control unit cyclically acquires parameters such as vehicle speed, gear, engine speed, throttle opening, driver-requested torque, brake pedal signal, auxiliary braking requested torque, actual auxiliary braking torque, turning radius, vehicle gradient, vehicle acceleration, and engine coolant temperature. The shift control unit logically compares the acquired real-time parameters with their corresponding calibrated values. The specific judgment conditions are as follows: vehicle speed is between a first preset speed and a second preset speed; the current gear is included in the calibrated gear sequence; engine speed is between a first preset engine speed and a second preset engine speed; throttle opening is less than or equal to a preset throttle opening threshold, and driver-requested torque is less than or equal to a preset driver-requested torque; brake pedal signal is not depressed; auxiliary braking requested torque is less than or equal to a preset auxiliary braking requested torque, and actual auxiliary braking torque is less than or equal to a preset actual auxiliary braking torque; turning radius is less than the target turning radius; vehicle gradient is between the target gradient lower limit and upper limit; vehicle acceleration is between the target acceleration lower limit and upper limit; and engine coolant temperature is between a first preset engine coolant temperature and a second preset engine coolant temperature. When all conditions are met simultaneously, the shift control unit outputs a flag indicating that the economic coasting conditions are met.

[0039] In step S20, after outputting the economic coasting condition satisfaction flag, the shift control unit acquires the operating status of the mechanical automatic transmission and pre-acquires the vehicle mass and current gear. It then uses a lookup table to obtain the target delay time for entering neutral coasting as a set time reference. When the mechanical automatic transmission is in gear, it checks if the economic coasting condition satisfaction flag is true. When the mechanical automatic transmission is in gear shifting mode, it acquires the input gear, checks if the input gear is not neutral, and checks if the economic coasting condition satisfaction flag is true. The shift control unit acquires the vehicle mass and current gear and obtains the target delay time for entering neutral coasting by looking up a table. The judgment conditions corresponding to gear operation or gear shifting are collectively referred to as state maintenance verification conditions. When one of the state maintenance verification conditions is satisfied, and the duration of satisfaction reaches the pre-acquired target delay time, the shift control unit activates the economic coasting state and sends an economic coasting state activation flag.

[0040] In step S30, the shift control unit executes the shifting process according to the operating state of the mechanical automatic transmission. When the conditions corresponding to in-gear operation are met, the mechanical automatic transmission enters the torque clearing process, and the shift control unit sends torque clearing status control requests to the clutch and engine respectively. The shift control unit acquires the operating states of the clutch and engine, and determines that the clutch operating state and the engine operating state are both torque clearing complete. When the conditions corresponding to shift execution are met, or the torque clearing completion condition is met, the mechanical automatic transmission enters the speed adjustment process, and the shift control unit sends a speed adjustment status control request to the clutch. The shift control unit acquires the clutch operating state, and when the clutch operating state is speed adjustment complete, it acquires the input shaft speed. When the input shaft speed is less than or equal to the target input shaft speed, the shift control unit issues a neutral execution command, and the actuator performs a neutral operation. The shift control unit acquires the input gear, and when the input gear is neutral and the neutral operation is completed, the mechanical automatic transmission enters the lock-up process and finally enters economic coasting.

[0041] In step S40, the shift control unit monitors the exit trigger conditions in the background during the economic coasting cycle. When any of the following occurs: a change in brake pedal state, throttle opening exceeding a set threshold, vehicle speed exceeding a calibrated range, vehicle gradient deviating from the limit, or turning radius deviating from the target limit, the system determines that the exit trigger conditions are met, and the shift control unit cancels the economic coasting state. The shift control unit calculates the target engagement gear based on the current vehicle speed and driving resistance, and instructs the shift actuator to engage the target engagement gear, restoring the mechanical automatic transmission to its in-gear operating state.

[0042] See attached document Figure 2Based on the overall process of the above embodiments, step S10 acquires vehicle operating state parameters and determines the conditions for coasting entry. Its specific implementation includes multi-dimensional data acquisition and comparison of the vehicle's basic dynamic state, driver's control intention, and chassis driving dynamics boundaries. This acquisition and determination step is specifically implemented through the following sub-steps:

[0043] In this embodiment, step S101 acquires basic power and transmission state parameters and performs interval determination. To avoid logical misjudgment due to signal delay, when the shift control unit reads the vehicle longitudinal driving speed signal calculated and converted by the chassis sensors through the vehicle communication bus, it needs to perform data alignment processing based on the bus message timestamp. After reading the current actual gear signal from its internal memory, the system performs operating condition interval evaluation based on the vehicle's basic dynamic characteristics. Specifically, the shift control unit's non-volatile memory is pre-written with a first preset vehicle speed and a second preset vehicle speed, which serve as the upper and lower limits for vehicle speed safety determination. It also stores a set of target gear sequences that allow coasting in neutral. The specific values ​​of the first and second preset vehicle speeds are determined by a comprehensive calibration of the vehicle's mass, drag coefficient, and transmission resistance, aiming to ensure that the benefits of coasting in neutral are greater than the fuel consumption of maintaining the original state. The shift control unit calculates and determines that the actually acquired longitudinal driving speed is within the closed interval of the first and second preset vehicle speeds, and determines that the actual gear signal belongs to the set of gear sequences. The specific logical determination expression is:

[0044] ;

[0045] ;

[0046] in, Indicates real-time vehicle speed; Indicates the first preset vehicle speed; Indicates the second preset speed; Indicates the current gear; Represents the set of gear sequences; Mathematical symbols that indicate that an element belongs to a specific set.

[0047] The technical purpose of the above-mentioned judgment process is to eliminate working conditions where fuel efficiency is extremely low at low speeds or where safety risks may arise at high speeds, and to exclude low gears that are not suitable for coasting from the permissible triggering conditions.

[0048] Based on the confirmation of the aforementioned basic power conditions, as a preferred approach, step S102 acquires the engine operating status and thermal management parameters and performs boundary determination. The shift control unit establishes communication with the engine control module and extracts the real-time engine speed signal and engine coolant temperature signal. Considering the operating characteristics of the internal combustion engine, the control system calibrates a first preset engine speed to maintain basic engine operation and a second preset engine speed to limit its upper limit. Simultaneously, it calibrates a first preset engine coolant temperature and a second preset engine coolant temperature to ensure normal engine cooling. The preset threshold range for coolant temperature is typically obtained based on engine bench thermodynamic tests to avoid poor lubrication at extreme low temperatures or thermal runaway at high temperatures. The shift control unit compares the input signals and determines that the real-time parameters are within the set safe value range.

[0049] ;

[0050] ;

[0051] in, Engine speed; The first preset engine speed; The second preset engine speed; Engine coolant temperature; The first preset engine coolant temperature; This is the second preset engine coolant temperature.

[0052] This calculation step aims to prevent the engine from stalling abnormally due to excessively low speed during decoupling coasting, while ensuring that the vehicle's thermal management system remains within a healthy operating range.

[0053] After confirming the safety of the power and thermal management status, the system needs to further evaluate the underlying driving behavior intentions. Step S103 obtains the driver's control intentions and braking system status parameters and performs intervention determination. The shift control unit obtains the current throttle opening and service brake pedal status by collecting the pedal sensor voltage signal and obtains the driver's requested torque, auxiliary braking requested torque, and auxiliary braking actual torque through bus message parsing. The control system stores preset throttle opening thresholds, preset driver requested torque, preset auxiliary braking requested torque, and preset auxiliary braking actual torque. The values ​​of the above preset values ​​are based on the calibrated dead zone threshold range for identifying the driver's intention not to actively accelerate or decelerate. Entering the economic coasting state requires no active intervention from the driving and braking systems. The shift control unit executes the comparison logic: verifying that the service brake pedal signal is not depressed; verifying that the throttle opening is less than or equal to the preset throttle opening threshold and the driver's requested torque is less than or equal to the preset driver requested torque; verifying that the auxiliary braking requested torque is less than or equal to the preset auxiliary braking requested torque and the auxiliary braking actual torque is less than or equal to the preset auxiliary braking actual torque. The corresponding comparison logic expression is:

[0054] ;

[0055] ;

[0056] ;

[0057] in, This represents the brake pedal signal status; the constant 0 corresponds to the unpressed state. This refers to the throttle opening. This is a preset throttle opening threshold; Request torque for the driver; Preset the torque requested by the driver; Requesting torque for auxiliary braking; Preset the required auxiliary braking torque; To assist braking with actual torque; The preset auxiliary braking actual torque; The AND operator indicates that both conditions connected to it must be true at the same time.

[0058] For the specific implementation methods of the underlying voltage signal conversion of vehicle sensors and the data transmission protocol of the controller local area network bus, those skilled in the art can use existing hardware drivers and communication standards to implement them. The underlying data acquisition and interaction principles are well-known technologies in this field and will not be elaborated here.

[0059] Besides the driver's direct intent, the external environment and the vehicle's own dynamics are the core factors determining coasting safety. Step S104 acquires the vehicle chassis dynamics parameters and performs dynamic safety judgment. The shift control unit acquires the current vehicle turning radius, vehicle slope, and vehicle acceleration signals from the vehicle stability system. Considering the different requirements for lateral and longitudinal adhesion and stability at different vehicle speeds, the control program internally allocates a calibration data mapping table indexed by vehicle speed. The shift control unit uses the current vehicle speed value as the input address variable, performs linear interpolation in the data mapping table, and dynamically outputs the target turning radius, target slope lower limit, target slope upper limit, target acceleration lower limit, and target acceleration upper limit matched with the current vehicle speed. After obtaining the dynamic limits, the shift control unit performs the following calculations: determining that the vehicle turning radius is less than the target turning radius; determining that the vehicle slope is greater than or equal to the target slope lower limit and less than or equal to the target slope upper limit; determining that the vehicle acceleration is greater than or equal to the target acceleration lower limit and less than or equal to the target acceleration upper limit. Its logical verification expression is:

[0060] ;

[0061] ;

[0062] ;

[0063] in, The turning radius of the vehicle; The target turning radius is obtained by looking up the table; For vehicle slope; This is the lower limit of the target slope. This represents the upper limit of the target slope. To accelerate the vehicle; The lower limit of the target acceleration; This represents the upper limit of the target acceleration.

[0064] The technical purpose of this determination is to prevent commercial vehicles from losing chassis control due to loss of engine braking force when encountering sharp bends, steep slopes, or severe acceleration and deceleration by establishing a dynamic coupling relationship between vehicle speed and dynamic boundaries.

[0065] After completing the feature determination of the above independent dimensions, a comprehensive decision on global safety and economic benefits is required. Step S105 executes the comprehensive logic operation and flag status output. Within a fixed control cycle, the shift control unit performs a logical AND calculation on all discrete Boolean operation results generated in steps S101 to S104. When the determination results of all the above constraints are true, the shift control unit sets the corresponding flag register inside the controller and outputs the economic coasting condition satisfaction flag as a prerequisite trigger signal for the underlying state machine to allow a jump. The comprehensive logic operation expression is:

[0066] ;

[0067] in, A Boolean variable representing the condition that economic gliding is met; The corresponding logical output results represent the ten independent sub-conditions included in the above steps, including vehicle speed, gear, engine speed, requested torque, brake pedal, auxiliary braking, turning radius, vehicle slope, vehicle acceleration, and coolant temperature. Indicates the index of each independent decision sub-condition; Indicates the sequence number from to All discrete subconditions are subjected to a continuous logical AND operation. The final overall judgment result is true if and only if all subconditions are true.

[0068] A rigorous parallel condition judgment mechanism is adopted to avoid the one-sidedness caused by relying solely on the extreme value judgment of a single parameter. This ensures that the system is only allowed to intervene in the subsequent coasting control mechanism when the multidimensional boundaries are in a steady state with absolute safety and economic benefits.

[0069] See attached document Figure 2 In the field of transmission system control, if an action is executed immediately after a preset condition is met, abrupt commands under transient conditions can easily cause underlying hardware logic conflicts and mechanical shocks. Therefore, in this embodiment, after outputting the flag indicating that the economic coasting condition is met, the control system does not immediately disconnect the power transmission. Instead, it executes step S20 through the shift control unit to identify the operating state of the mechanical automatic transmission and perform delayed control. The system classifies and verifies the mechanical execution state of the transmission, and its specific implementation process is achieved through the following sub-steps:

[0070] Based on the overall condition judgment result output by the previous step, the system needs to further confirm the current stage of mechanical coupling in the transmission system. Step S201 obtains the in-gear operating status of the mechanical automatic transmission and performs the previous verification. The shift control unit reads the current operating status of the mechanical automatic transmission in real time through the internal communication bus. When it is identified that the operating status is in gear, it means that the transmission system is currently in a stable torque transmission closed loop. At this time, the shift control unit extracts the economic coasting condition satisfaction status output by the previous step and determines whether the condition satisfaction flag is true. Its logical verification expression is:

[0071] ;

[0072] in, This indicates the actual operating status of a mechanical automatic transmission; This represents the preset enumerated value of the in-gear operating state, which usually corresponds to a specific integer flag bit in the underlying controller; A flag indicating that the economic coasting conditions output by the pre-calculated parameters are met; constants It represents the true state of Boolean logic.

[0073] The technical purpose of this step is to ensure that, under stable driving conditions, subsequent coasting control permissions are only granted when the overall safety and economic boundary conditions are fully met.

[0074] Besides steady-state operation in gear, due to the complex driving environment of commercial vehicles, the system may be in a transient shifting state during the underlying shift fork scheduling. For such conditions, step S202 obtains the shifting execution status of the mechanical automatic transmission and filters the execution intent. When the shift control unit recognizes that the mechanical automatic transmission is in shifting execution mode, the system is internally scheduling mechanical mechanisms such as shift forks. The shift control unit obtains the target input gear from the underlying hardware abstraction layer and determines whether the input gear is not in neutral. If it is determined that the input gear is not in neutral, i.e., the underlying execution sequence is in the clearing torque phase and has not yet disengaged neutral, or in the return torque phase and has already engaged a new gear, the shift control unit further extracts and determines whether the economic coasting condition satisfaction flag is true. The relevant logical verification expression is:

[0075] ;

[0076] in, This represents the preset gear shift execution state enumeration value; Indicates the target input gear that the system is currently requesting or executing; This represents the empty space enumeration value defined by the system.

[0077] The introduction of the restriction that the input gear is not in neutral is to filter out overlapping situations where the system itself has already triggered the neutral shift action due to other logic (such as normal deceleration and downshifting), so as to avoid the underlying actuator receiving repeated neutral execution instructions and causing logical conflicts and system deadlocks.

[0078] Based on the results of the aforementioned state recognition, as a preferred approach, step S203 performs an adaptive lookup table calculation for the target delay time. Considering that the vehicle's inertia and transmission ratio directly determine the magnitude of the transient anti-drag torque of the transmission system, abrupt decoupling when the torque is large will cause longitudinal impact on the vehicle. Therefore, selecting the vehicle mass and current gear as input parameters has a clear physical causal relationship. The shift control unit obtains the current vehicle mass from the vehicle controller or internal observer, and simultaneously reads the current actual gear. A two-dimensional data lookup table matrix is ​​burned into the control program's storage medium. The shift control unit uses the vehicle mass and current gear as dual input indices, performs a two-dimensional lookup table operation to obtain the target delay time for entering neutral coasting, and uses it as the time comparison benchmark for subsequent delay control. The corresponding mathematical mapping relationship is:

[0079] ;

[0080] in, To calculate the target delay time of the output; This represents a two-dimensional data mapping table that has been pre-established through bench calibration; This is the currently estimated total vehicle weight; The current gear.

[0081] In practical engineering applications, the calibration rule for this two-dimensional mapping table is: the greater the vehicle mass or the lower the gear, the corresponding delay time... The longer the value range, the more likely it is to be calibrated between 0.5 and 3.0 seconds to provide a sufficient buffer observation window. For real-time estimation of the vehicle mass, those skilled in the art can use conventional Kalman filtering and other observer algorithms based on the longitudinal dynamic equations to obtain the data through the vehicle network. The specific mass estimation principle is a well-known technology in this field and will not be elaborated here.

[0082] After pre-calculating and obtaining the dynamic delay threshold, in order to implement the anti-jitter mechanism in the digital controller, step S204 executes state timing and trigger activation. The actual on-board microprocessor performs calculations through a fixed discrete clock cycle. Within the fixed control clock cycle, the system cyclically checks the in-gear operation judgment condition defined in step S201 and the shift execution judgment condition defined in step S202. These two judgment conditions together constitute the state maintenance verification condition. When any one of the state maintenance verification conditions is met, the shift control unit starts its internal accumulator timer. When the duration for which the condition is continuously met reaches the target delay time pre-obtained in step S203, the shift control unit officially activates the economic coasting state and sends an economic coasting state activation flag to the underlying state machine. Its discrete time integral and trigger logic expression is:

[0083] ;

[0084] ;

[0085] in, Represents the global discrete control period of the system. For the current number The cumulative time of each control cycle; This is the cumulative time of the previous period; The sampling period for the control unit's operation (typically 10ms or 20ms). The Boolean result indicating that the logical expression for the current cycle step S201 is true; The Boolean result indicating that the logical expression for the current cycle step S202 is true; Activate the flag for the output of the economic coasting state; It represents a logical OR operation, indicating that a condition is true if either one of the two conditions is met.

[0086] The aforementioned reset equation stipulates that if any of the basic judgment conditions fails for an extremely short time during the timing period, the value of the accumulator timer will be forcibly reset to zero. By introducing an adaptive time window triggering mechanism, high-frequency noise signals such as the instantaneous release and re-pressing of the accelerator pedal are effectively filtered out, preventing abnormal clutch wear and power surges caused by frequent decoupling and engagement of the transmission system.

[0087] See attached document Figure 2 After confirming the economic coasting trigger condition and completing the adaptive delay, the control system formally takes over the underlying execution of the powertrain system. Since the system may be in different mechanical states when initiating a coasting command, using a single linear control logic is highly susceptible to mechanical interference and underlying timing conflicts. Therefore, in this embodiment, the shift control unit executes step S30, scheduling the clutch, engine, and shift actuator to perform the micro-mechanical actions of torque unloading and speed synchronization based on the different trigger source states. This differentiated execution process is specifically implemented through the following sub-steps:

[0088] Based on the principle that the normal force on the gear meshing surface must be unloaded before the rigid connection of the transmission system is disengaged, step S301 executes an active torque clearing process triggered by the in-gear operating state. Under the steady-state closed-loop condition of the transmission system, directly dispatching the shift fork to disengage the gear will cause severe gear grinding due to excessive load. The system extracts the trigger source state recorded in the previous step. If it is identified that the coasting is triggered by the in-gear operating state, the shift control unit sends a torque clearing control request to the clutch controller and engine control module. This request instructs the clutch to disengage to a semi-engaged state or fully disengaged, and instructs the engine to quickly reduce the output torque. Considering that the actual output torque of the engine needs to be transmitted across nodes via the vehicle controller LAN bus, the shift control unit stores a circular queue containing timestamps locally, and uses a time alignment algorithm to synchronize and pair the bus torque message with the locally high-frequency estimated clutch transmission torque. Within a rolling time window, the control system cyclically collects the actual clutch transmission torque and the actual engine output torque, and determines whether both have reached the torque clearing completion state. Its feedback verification logic expression is:

[0089] ;

[0090] ;

[0091] in, The actual torque transmitted by the clutch after time alignment is usually obtained by the controller by looking up the value of the clutch displacement sensor in combination with the transmission characteristic curve. The clutch torque clearing threshold has been reached; The actual output torque fed back by the engine control module; The target coasting torque for the engine is usually set as the basic anti-drag friction torque to keep the engine from stalling; This is the engine torque control error threshold.

[0092] The values ​​of the two thresholds mentioned above are typically determined by bench calibration based on the disengagement impedance of the gear meshing in the transmission system, and are set between 5 N·m and 15 N·m. The technical purpose of this calculation step is to actively break the original rigid torque coupling closed loop, providing a low-load foundation environment for subsequent mechanical decoupling.

[0093] In the case of a shifting transient, the underlying actuator has already spontaneously initiated a torque unloading action. If a new torque clearing command is blindly issued at this time, it will inevitably lead to a chaotic deadlock in the controller's underlying state machine. As a preferred approach, step S302 executes a skip-level identification and speed synchronization adjustment process. If the system identifies the trigger source as a shifting execution state, it skips the issuance of the aforementioned active torque clearing request; however, after confirming that the system is in gear and the aforementioned torque clearing process is complete, the system issues a speed control request to the clutch and engine. The core general technical principle of speed control lies in actively adjusting the input speed to eliminate the relative speed difference between the input and output shafts, thereby unloading the normal force on the gear meshing surface. The shift control unit obtains the current transmission output shaft speed and the mechanical speed ratio of the gear before the target shift is disengaged, and calculates the target input shaft speed. To avoid memory overflow or calculation abnormalities in the microcontroller due to the denominator approaching zero when using division to obtain the speed ratio at extremely low vehicle speeds, this embodiment uses multiplication combined with an absolute difference verification algorithm to confirm the speed adjustment completion status. The relevant calculation and judgment expressions are as follows:

[0094] ;

[0095] ;

[0096] ;

[0097] in, The target input shaft speed is calculated; This refers to the output shaft speed of the transmission; The mechanical speed ratio of the current gear; This represents the absolute value of the input shaft speed error. The actual input shaft speed is collected by the sensor; The speed error threshold for determining the completion of speed regulation is usually set in the range of 30 rpm to 50 rpm, which takes into account sensor measurement noise and mechanical drag resistance.

[0098] To prevent misjudgments caused by signal spikes due to transient vibrations, the system needs to confirm that the absolute value of the rotational speed error meets the threshold condition for multiple consecutive sampling periods before determining that the micro-rotational speed synchronization is complete, thereby obtaining the dynamic boundary for shock-free gear shifting. For the specific filtering algorithm used to calculate the rotational speed from the high-frequency pulse signal acquired by the sensor, those skilled in the art can employ conventional moving average filtering. The signal processing and extraction techniques are well-known in the field and will not be elaborated upon here.

[0099] After confirming micro-speed synchronization and torque unloading, step S303 executes the neutral command issuance and disengagement lock confirmation. The shift control unit issues a neutral execution command to the shift selector actuator. Due to the non-negligible delay in the charging / discharging / hydraulic / hydraulic operation of the hydraulic or pneumatic actuator, the controller needs to monitor the shift fork position feedback signal in real time to form a control closed loop. The system collects the actual position value of the shift displacement sensor and calculates its absolute deviation from the calibrated neutral center position. When this deviation is continuously less than the allowable tolerance within the preset confirmation time window, the input gear is confirmed to have been disengaged into neutral, and the underlying state machine is driven into the logic lock-up stage of the economic coasting state execution. Its closed-loop determination logic expression is:

[0100] ;

[0101] ;

[0102] in, This is the actual position feedback value of the shift displacement sensor; To determine the coordinates of the center position of the stored empty space; The allowable displacement installation and manufacturing tolerance threshold is determined based on the free play clearance of the mechanical shift fork, and is usually between 0.5mm and 1.5mm. The cumulative time of the discrete integral during which the position is continuously maintained within the tolerance range; Total number of inspection cycles; The sampling period for the control unit's operation (typically 10ms or 20ms). The preset idle time confirmation threshold, Indicates the current sequence number index of the inspection cycle; Indicates the sequence number from to The discrete time steps within the continuous inspection cycle are used to perform cumulative summation.

[0103] To ensure the absolute completeness of the algorithm's closed loop, if the displacement deviation still exceeds the tolerance threshold after the neutral command has been issued and the preset physical limit braking time limit has been exceeded, the shift control unit will determine that there is a mechanical jamming anomaly, immediately interrupt the economic coasting process, and forcibly restore the original gear, thus preventing the state machine from deadlocking. This logic utilizes a two-dimensional joint judgment based on positional spatial deviation and time axis, effectively preventing the sensor's single-frame value jump caused by severe mechanical vibration of the heavy-duty commercial vehicle chassis from being mistakenly judged as a successful disengagement. This ensures that the final economic coasting execution process is locked and monitored in an absolutely safe physical disengagement state. Furthermore, the preset physical limit braking time limit is set to a range of 500ms to 1000ms.

[0104] See attached document Figure 2When the system is in the economic coasting condition, the vehicle's power cut-off alters the original driving resistance model. Given the unpredictability of the driving environment and the high randomness of driver operation, the control logic needs to establish a continuous background monitoring and seamless takeover mechanism. In this embodiment, the shift control unit executes step S40, cyclically monitoring the exit trigger conditions throughout the entire economic coasting lifecycle and performing closed-loop control for state recovery. This monitoring and recovery mechanism is specifically implemented through the following sub-steps:

[0105] Based on the control principle that prioritizes driving safety over economy, step S401 performs parallel monitoring and anti-shake verification of multi-source exit trigger conditions. In each control cycle, the shift control unit's background process receives data from the bus on brake pedal status, throttle opening, real-time vehicle speed, vehicle gradient, and turning radius. Considering that these multi-source signals are sent by different external control nodes at different frame periods, the shift control unit introduces a timestamp-based zero-order hold logic to align and sample asynchronous data. Simultaneously, to avoid system misjudgments caused by transient voltage spikes from sensors due to road bumps, the control program employs a sliding time window continuous verification mechanism. The system evaluates whether the aligned parameters continuously deviate from the preset safety limits within the set time window; the joint judgment logic expression is as follows:

[0106] ;

[0107] in, To calculate the output of the coasting exit flag; This represents the total number of sampling periods within the time window. This is a Boolean value representing the brake pedal being depressed; a value of 1 corresponds to the physical depressing action. This refers to the throttle opening. Preset the throttle opening threshold (the calibration range is usually 3% to 5%, used to filter out pedal mechanical play); Real-time vehicle speed; and These are the first preset vehicle speed and the second preset vehicle speed, respectively. For vehicle slope; and For safe lower and upper limits of slope; The turning radius; This represents the lower limit of the target turning radius for safety. This is the index of the current sampling period within the sliding time window; For the time window, the sequence number is... to The Boolean decision result performs a continuous logical OR operation, meaning that as long as any one of the out-of-bounds conditions is met in any period within the time window, the final output will be true.

[0108] The technical purpose of the above judgment is to establish a multi-dimensional safety exit interception network and ensure that the system only recognizes a dangerous operating condition or takeover intention as a real exit signal when it shows a stable trend.

[0109] Upon confirmation of the takeover intent, the system must immediately suspend the current coasting control flow. Step S402 executes the economic coasting state cancellation and control transfer. The shift control unit resets its internal economic coasting state activation flag and related control state machine registers. As a preferred method, to reduce bus arbitration latency, the shift control unit sends a high-priority event-triggered takeover message to the clutch controller and engine control module, forcibly overriding the underlying instructions currently in the idle or disengagement state. The relevant state reset expression is:

[0110] ;

[0111] ;

[0112] in, This indicates the activation of the economic gliding state. For the global control mode variable of the shift control unit; This is the enumerated value for the normal power drive mode. This reset operation releases the coasting control logic from the software state machine level, allowing the drivetrain control to smoothly return to the basic pedal torque mapping framework.

[0113] After disengaging from coasting, the vehicle has already experienced speed decay or acceleration due to inertia during this period, and the original gear at the time of disengagement is highly likely no longer suitable for the current vehicle speed. If the original gear is rigidly engaged directly, it could cause severe longitudinal jerking, or even engine over-revving and damage. Therefore, step S403 performs the target engagement gear calculation and state recovery synchronization. The shift control unit, based on the current real-time vehicle speed and chassis mechanical parameters, reverse-engineers the optimal gear ratio to meet the current vehicle speed. To avoid microcontroller memory overflow or data anomalies during division operations when the vehicle is at extremely low speeds or even near a standstill, this embodiment introduces an extremely low speed protection lower limit in the divisor term. The calculation and gear matching expression for the target gear ratio are as follows:

[0114] ;

[0115] ;

[0116] ;

[0117] in, The base speed for calculation after zero-prevention protection; The real-time vehicle speed is expressed in kilometers per hour (km / h). The extremely low speed protection threshold is typically set between 3 km / h and 5 km / h. The target transmission ratio is obtained through inverse calculation; These are fixed physical constant coefficients that include pi and unit conversions; The target engine speed after combination is determined based on the high-efficiency zone in the universal characteristic map of engine fuel consumption rate, and is usually selected in the range of 1100rpm to 1400rpm. The radius of the wheel's rolling radius is expressed in meters (m). This refers to the main reduction ratio of the drive axle; Combine the target obtained through traversal optimization with the gear position; The set of all available forward gears included in the transmission; For a specific gear The corresponding speed ratio parameters; This is a function to find the maximum value, used to select the larger of the input parameters within the parentheses; This is a minimum value function used to find the minimum value of the absolute difference in speed ratios during the traversal process; This is an optimization function for the independent variable, used to return the specific gear parameter variable that minimizes the subsequent functional relationship.

[0118] For obtaining the wheel rolling radius and reading the drive axle main reduction ratio, those skilled in the art can obtain them by querying the vehicle assembly parameter matrix. The principle of static parameter configuration is a well-known technology in this field and will not be elaborated here.

[0119] After finding the target gear, the final step in restoring the state is to smoothly bridge the energy gap. The shift control unit sends a command to the shift actuator to engage the target gear. The system issues instructions to the engine control module to perform active speed-up control, and simultaneously calculates the target speed of the clutch input shaft based on the target gear ratio. To prevent reverse impact caused by overshoot in the integral stage during engine speed adjustment, the system introduces a closed-loop determination of the speed synchronization tolerance window. When the absolute value of the difference between the actual engine speed and the input shaft speed stabilizes within the set speed synchronization tolerance threshold (usually calibrated to 30 rpm to 50 rpm) for several consecutive calculation cycles, the shift control unit issues a clutch engagement command. The above closed-loop synchronization process ensures that the transmission system smoothly transitions from a decoupled state to in-gear closed-loop operation, completing the safe exit of the coasting control logic and the restoration of the normal drive mechanism.

[0120] This embodiment also provides an AMT (Autonomous Treadmill) economic coasting control system, which specifically includes:

[0121] Condition Determination Module: This module acquires vehicle operating status parameters and determines the conditions for coasting. Specifically, it collects real-time parameters such as longitudinal vehicle speed, engine speed, coolant temperature, pedal status, and torque. When all parameters meet the set conditions, it outputs a flag indicating that the economic coasting conditions are met.

[0122] Delay control module: Connected to the condition determination module, it obtains the target delay time by combining the vehicle weight and the current gear in a two-dimensional lookup table after acquiring the satisfaction flag, and maintains and verifies the in-gear operation or gear shift execution state. It has an internal accumulator timer; when the verification condition is continuously satisfied for the duration reaching the target delay time, it issues an activation flag, effectively filtering out false trigger signals.

[0123] Decoupling Execution Module: This module is used to execute the neutral coasting process after receiving the activation flag. It incorporates torque clearing logic, speed adjustment sub-logic, and neutral execution sub-logic. Through time alignment algorithms and closed-loop position monitoring, it ensures smooth decoupling of the clutch and engine, and accurate positioning of the actuator into the neutral center position.

[0124] State recovery module: Running in real time in the background, it uses zero-order hold logic and sliding time window mechanism to monitor exit conditions. Once triggered, this module is responsible for canceling the coasting state, calculating the target transmission ratio to prevent zero division and optimizing the gear traversal, and linking with the engine control module to perform active acceleration control. When the speed difference enters the synchronization tolerance threshold (such as 30rpm to 50rpm), it engages the clutch and smoothly resumes in-gear operation.

[0125] It should be noted that, in practical applications, each module / unit in the above system embodiments can be materialized through software algorithms in the vehicle controller (VCU) or transmission control unit (TCU), or it can be embodied as a hardware device including a processor, memory and a computer program stored in the memory and capable of running on the processor.

[0126] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An AMT (Automated Manual Transmission) economic coasting control method, characterized in that, Includes the following steps: The vehicle's operating status parameters are acquired and the conditions for coasting are determined. When the acquired real-time parameters meet all the preset judgment conditions, an economic coasting condition is satisfied flag is output. After outputting the flag indicating that the economic coasting condition is met, the operating status of the mechanical automatic transmission is obtained, it is determined whether the operating status of the mechanical automatic transmission meets the state maintenance verification condition and delay control is performed, and a preset target delay time is obtained. When the duration for which the state maintenance verification condition is continuously met reaches the target delay time, the economic coasting state is activated and an economic coasting state activation flag is sent. After obtaining the economic coasting state activation flag, the neutral coasting process is executed according to the operating state of the mechanical automatic transmission, completing the decoupling of the transmission system and finally entering economic coasting. During the economic coasting cycle, the background monitors the exit trigger condition. When the exit trigger condition is met, the economic coasting state is canceled, the target gear is calculated, and the target gear is engaged to restore the mechanical automatic transmission to its in-gear operation state.

2. The AMT economic coasting control method according to claim 1, characterized in that, The specific conditions for determining taxi entry include: When all the above judgment conditions are met at the same time, output the economic gliding condition satisfaction flag; If any of the judgment conditions are not met, then the flag indicating that the economic gliding condition is met will not be output: The actual longitudinal driving speed is within the closed interval between the first preset speed and the second preset speed, and the current gear is included in the set gear sequence. The real-time engine speed is within the range of the first preset engine speed and the second preset engine speed, and the engine coolant temperature is within the range of the first preset engine coolant temperature and the second preset engine coolant temperature. The service brake pedal signal is not depressed, the throttle opening is less than or equal to the preset throttle opening threshold, the driver's requested torque is less than or equal to the preset driver's requested torque, the auxiliary braking requested torque is less than or equal to the preset auxiliary braking requested torque, and the actual auxiliary braking torque is less than or equal to the preset actual auxiliary braking torque. The vehicle's turning radius is smaller than the target turning radius, the vehicle's slope is between the lower limit and the upper limit of the target slope, and the vehicle's acceleration is between the lower limit and the upper limit of the target acceleration. The specific range of the first preset vehicle speed and the second preset vehicle speed is determined by a comprehensive calibration of the vehicle mass, drag coefficient and transmission system resistance. The first preset engine speed is the speed used to maintain the basic operation of the engine, and the second preset engine speed is the speed used to limit the upper limit. The values ​​of the first preset engine coolant temperature and the second preset engine coolant temperature are obtained based on the engine bench thermodynamic test calibration. The preset throttle opening threshold value is between 3% and 5%; The values ​​of the preset driver-requested torque, preset auxiliary braking requested torque, and preset auxiliary braking actual torque are determined based on the calibrated dead zone threshold range for identifying when the driver has no intention to actively accelerate or decelerate.

3. The AMT economic coasting control method according to claim 1, characterized in that, Obtaining a preset target delay time, determining whether the operating state of the mechanical automatic transmission meets the state maintenance verification condition, and performing delay control specifically includes: Obtain the vehicle mass and current gear, and use the vehicle mass and current gear as dual input indices to perform a two-dimensional lookup table operation to pre-calculate the target delay time for entering neutral coasting; When the mechanical automatic transmission is in gear, it is determined whether the economic coasting condition is met. If it is, the judgment condition corresponding to the gear operation is determined to be met; otherwise, it is determined not to be met. When the mechanical automatic transmission is in the gear shift execution state, the input gear is obtained, it is determined whether the input gear is in a non-neutral state, and it is determined whether the economic coasting condition satisfaction flag is true. If both are true, the judgment condition corresponding to the gear shift execution is determined to be true; otherwise, the judgment is not true. The judgment conditions corresponding to in-gear operation or the judgment conditions corresponding to gear shift execution together constitute the state maintenance verification conditions. The system continuously detects within the control clock cycle. When any one of the state maintenance verification conditions is met, an internal accumulator timer is started. If the duration for which the state maintenance verification condition is met reaches the target delay time, the economic coasting state is activated and the economic coasting state activation flag is sent. If the state maintenance verification condition fails during the timing period and is no longer satisfied, the value of the internal accumulator timer will be forcibly cleared to zero.

4. The AMT economic coasting control method according to claim 3, characterized in that, The specific steps of executing the neutral coasting process based on the operating state of the mechanical automatic transmission include: When it is recognized that the coasting is triggered by the in-gear operating state, the mechanical automatic transmission enters the torque clearing process and sends torque clearing state control requests to the clutch and engine respectively. The operating status of the clutch and the engine is obtained. When the clutch operating status is "torque clearing complete" and the engine operating status is "torque clearing complete", the mechanical automatic transmission enters the speed adjustment process. When it is recognized that coasting is triggered by the shift execution state, the action of issuing the torque clearing state control request is skipped, and the speed adjustment process is directly entered. During the speed regulation process, a speed regulation status control request is sent to the clutch to determine whether the speed regulation is completed. When the clutch operating status is determined to be speed regulation completed, a neutral gear execution command is issued and the actuator performs a neutral gear operation. The system obtains the current actual input gear and confirms whether the neutral operation is completed. When the input gear is neutral and the neutral operation is confirmed to be completed, the mechanical automatic transmission enters the locking process and finally enters the economic coasting.

5. The AMT economic coasting control method according to claim 4, characterized in that, Determining whether the torque clearing is complete specifically includes: The bus torque message is synchronized and paired with the locally high-frequency estimated clutch transmission torque using a time alignment algorithm; When the actual torque transmitted by the clutch obtained after time alignment is less than or equal to the clutch torque clearing completion threshold, and the difference between the actual output torque of the engine and the engine target coasting torque is less than or equal to the engine torque control error threshold, the torque clearing is determined to be complete. If the above threshold conditions are not met, it is determined that the cleanup is not completed and the cleanup process continues. The clutch torque clearing completion threshold ranges from 5 N·m to 15 N·m, and the engine torque control error threshold ranges from 5 N·m to 15 N·m.

6. The AMT economic coasting control method according to claim 4, characterized in that, Determining whether speed adjustment is complete specifically includes: The current transmission output shaft speed and the mechanical speed ratio of the gear before the target gear is disengaged are obtained. The target input shaft speed is calculated by multiplying the transmission output shaft speed by the mechanical speed ratio. Calculate the absolute value of the input shaft speed error between the actual input shaft speed and the target input shaft speed; When the absolute value of the input shaft speed error is less than or equal to the speed error threshold for speed regulation completion determination for multiple consecutive sampling periods, speed regulation is determined to be complete. When the absolute value of the input shaft speed error does not meet the condition that it is less than or equal to the speed error threshold for multiple consecutive sampling periods, it is determined that the speed regulation is not completed and the speed regulation state is maintained. The speed error threshold is set within the range of 30 rpm to 50 rpm.

7. The AMT economic coasting control method according to claim 4, characterized in that, Confirming whether the neutral shift is complete includes: The position feedback signal of the shift fork is monitored in real time, the actual position value of the shift displacement sensor is collected, and the absolute deviation between the actual position value and the calibrated neutral center position coordinates is calculated. When the absolute deviation is continuously less than or equal to the allowable displacement installation and manufacturing tolerance threshold within the preset confirmation time window, the neutral operation is confirmed to be completed. If the absolute deviation is still greater than the tolerance threshold after the preset physical limit braking time limit is exceeded from the time the neutral gear execution command is issued, the mechanical jamming is determined to be abnormal, the economic coasting process is interrupted and the original gear is forcibly restored. The allowable displacement installation and manufacturing tolerance threshold is between 0.5mm and 1.5mm, and the preset physical limit braking time limit is between 500ms and 1000ms.

8. The AMT economic coasting control method according to claim 2, characterized in that, The specific conditions for triggering the exit of background monitoring include: A time-stamp-based zero-order hold logic is introduced to align and sample asynchronous data, thereby obtaining aligned data such as brake pedal state, throttle opening, real-time vehicle speed, vehicle gradient, and turning radius. A continuous verification mechanism using a sliding time window is adopted. When any of the following occurs within a sliding time window: the brake pedal state changes to a depressed action, the throttle opening is greater than a preset throttle opening threshold, the real-time vehicle speed is not between the first preset vehicle speed and the second preset vehicle speed, the vehicle slope deviates from the safe lower and upper slope limits, or the turning radius is less than the target turning radius safe lower limit, it is determined that the exit trigger condition is met. If none of the above-mentioned events are detected within the sliding time window, it is determined that the exit trigger condition has not been met, and the economical gliding state is maintained. The preset throttle opening threshold value is between 3% and 5%.

9. The AMT economic coasting control method according to claim 1, characterized in that, The process of canceling the coasting mode, calculating the target gear engagement, and engaging the target gear to restore the mechanical automatic transmission to its in-gear operating state specifically includes: The economic coasting state activation flag and related control state machine registers are reset to zero, thus canceling the economic coasting state and sending an event-triggered takeover message to the clutch controller and engine control module to overwrite the underlying instructions. The larger of the current real-time vehicle speed and the set extremely low speed protection threshold is selected as the calculation benchmark speed for zero-reduction protection. Based on the combined target engine speed, wheel rolling radius, drive axle main reduction ratio and the calculated reference vehicle speed, the target transmission ratio is derived in reverse. The system iterates through all available forward gears in the transmission to find the absolute difference between the gear ratio parameter corresponding to each gear and the target transmission ratio. The specific gear that minimizes the absolute difference in gear ratio is selected as the target gear. The instruction shifting actuator engages the target gear position and simultaneously calculates the target rotational speed of the clutch input shaft based on the target gear ratio; The engine control module is given a command to perform active speed-up control. When the absolute value of the difference between the actual engine speed and the input shaft speed is stable within the set speed synchronization tolerance threshold for several consecutive calculation cycles, the clutch engagement command is given to restore the in-gear operation state of the mechanical automatic transmission. If the absolute value of the difference fails to stabilize within the set speed synchronization tolerance threshold, the active speed increase control will continue until synchronization is completed. The extremely low speed protection threshold is calibrated between 3 km / h and 5 km / h, the target engine speed is selected within the range of 1100 rpm to 1400 rpm, and the speed synchronization tolerance threshold is calibrated between 30 rpm and 50 rpm.

10. An AMT (Automated Manual Transmission) economic coasting control system, characterized in that, The method applied to the AMT economic coasting control method according to any one of claims 1-9 includes: The condition determination module is used to acquire vehicle operating status parameters and determine the conditions for coasting. When the acquired vehicle operating status parameters meet all preset judgment conditions, an economic coasting condition satisfaction flag is output. The delay control module is used to obtain the operating status of the mechanical automatic transmission after outputting the economic coasting condition satisfaction flag, and obtain the target delay time, determine whether the operating status of the mechanical automatic transmission satisfies the state maintenance verification condition and perform delay control, and when the duration for which the state maintenance verification condition is continuously satisfied reaches the target delay time, activate the economic coasting state and send the economic coasting state activation flag. The decoupling execution module is used to execute the neutral coasting process according to the operating state of the mechanical automatic transmission after obtaining the economic coasting state activation flag, thereby completing the decoupling of the transmission system and finally entering economic coasting. The state recovery module is used to monitor the exit trigger condition in the background during the economic coasting cycle. When the exit trigger condition is detected, the economic coasting state is canceled, the target gear is calculated, and the target gear is engaged to restore the mechanical automatic transmission to the in-gear operation state.

Images