Drive control method, device and system for hydrostatic drive vehicle

Abstract

The invention discloses a driving control method, device and system for a hydrostatic driving vehicle, and the method comprises the steps: adjusting the displacement of a large-displacement motor when the vehicle is judged to be at a low-speed gear at the same time, double motors act at the same time and the vehicle speed exceeds the maximum speed set by the low-speed gear based on the real-time state data of the vehicle, and controlling the displacement of the large-displacement motor to be smaller than the maximum speed set by the low-speed gear; the vehicle speed is in a set speed interval, the large-displacement motor is kept in a meshed state, and reverse dragging torque is provided all the time; acquiring position information of an accelerator pedal; the engagement speed of the large-displacement motor engaged to the driving system is controlled according to the position information of the accelerator pedal, so that the frequency of disengaging the large-displacement motor from the driving system is reduced. The low-speed-gear clutch can be prevented from being disengaged and triggered, the large-displacement motor is kept in an engaged state, reverse dragging torque is provided all the time, the low-speed-gear downhill speed is stable and controllable, the closing and disengaging frequency of the clutch is reduced, and therefore sliding friction of the clutch is reduced, and the service life of the clutch is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of engineering machinery, and in particular relates to a drive control method, device and system for a hydrostatic drive vehicle. Background Art

[0002] The static hydraulic drive uses a hydraulic pump and a hydraulic motor to form a closed hydraulic circuit to achieve walking drive. In order to take into account the requirements of high torque in operation and high speed in driving, the hydraulic pump + dual hydraulic motor + transfer case (with clutch) solution is widely used. The hydraulic pump is a closed electronically controlled variable pump. The dual motors are two hydraulic motors of different displacements, one of which is a large-displacement electronically controlled variable motor, and the other is a small-displacement electronically controlled variable motor or a fixed-displacement motor. The transfer case has two input shafts and one output shaft, and a clutch is provided between one of the input shafts and the output shaft. The large and small displacement hydraulic motors are connected to the transfer case input shaft through the output shaft, and the transfer case input shaft to the output shaft forms different transmissions through gears with different numbers of teeth. The transmission ratio of the transfer case input shaft to the transfer case output shaft is greater than the transmission ratio of the transfer case input shaft to the transfer case output shaft connected to the large-displacement motor, wherein the large-displacement motor can be controlled by the clutch of the transfer case to achieve the disengagement or engagement of the large-displacement motor. When the large-displacement motor is engaged with the transfer case transmission system, the dual motors act at the same time. With the help of the large transmission ratio of the transfer case output shaft and the large displacement state of the motor, the large-torque operation requirement is achieved. After the large-displacement motor is disengaged from the transfer case transmission system, only the small-displacement motor acts, and the hydraulic oil output by the hydraulic pump is all directed to the small-displacement motor, thereby achieving high-speed driving requirements. Taking into account the large displacement motor to the transfer case output shaft transmission is relatively large, after reaching a certain speed, the large displacement motor needs to be disengaged due to the high speed to avoid motor overspeed damage. After falling below a certain speed, it needs to be engaged in time to meet the requirements of climbing, digging and other working conditions that require large traction. In the process of clutch disengagement and closing, the large displacement motor is disengaged and engaged to the transfer case transmission system. The clutch has slippage and heat generation. Therefore, frequent clutch separation and closing during driving can easily cause clutch damage and reduce the service life of the clutch. At the same time, in the process of large displacement motor disengagement and engagement with the transmission system, it is necessary to ensure that the conversion process is smooth, otherwise it is easy to cause speed shock during driving.

[0003] In order to achieve high-speed driving requirements, the clutch is controlled to disengage the large-displacement motor. According to the speed capacity of the large-displacement motor corresponding to the vehicle speed critical value, the large-displacement motor can be controlled to disengage when the vehicle speed is lower than or equal to the critical value. Usually, the motor disengagement condition will be triggered in high-speed gear, but in downhill conditions, even in low-speed gear, when the critical speed is exceeded, the large-displacement motor will actively disengage to prevent overspeeding of the large-displacement motor and cause damage to the motor.

[0004] In order to achieve the requirement of low speed and high torque, the clutch is controlled to engage the large displacement motor. Some solutions set the engagement speed according to the speed request corresponding to the coupling of the accelerator pedal and the inch pedal, and further reduce the engagement speed when the actual requested speed is lower than the predetermined speed value and is in a deceleration state; some solutions, when the clutch is in a disengaged state, perform active downshift engagement at low engine speed and passive downshift engagement under high load pressure according to the current speed of the vehicle engine, the target downshift gear of the vehicle, the vehicle speed and the load pressure.

[0005] The above prior art has the following technical problems: When the vehicle is in a low gear and going downhill, the vehicle load causes the vehicle speed to increase (not the vehicle acceleration caused by shifting to a high gear), the large-displacement motor has a high speed. After reaching the set speed limit, the clutch is actively controlled to disengage the large-displacement motor from the transfer case transmission system. After disengagement, only the small-displacement motor works. During the downhill process, the reverse drag torque is small, causing stalling. The vehicle speed is difficult to control, which can easily cause safety problems.

[0006] During high-speed driving, the vehicle speed drops below the set value and the clutch is closed in combination with the engine speed to engage the large-displacement motor. Some solutions consider closing the clutch at a lower speed after the accelerator pedal is released to a very small value (corresponding to a lower speed request). In other states of the accelerator pedal, the clutch is still engaged at the set speed or a higher speed. During the deceleration process, the clutch is easily triggered to close, and then after the vehicle speeds up, the clutch is disengaged again. The acceleration and deceleration during driving can easily trigger the disengagement and engagement of the large-displacement motor, which can easily cause slip and heat generation problems in the transfer case clutch, reducing the service life of the clutch. Summary of the invention

[0007] In view of the above problems, the present invention proposes a drive control method, device and system for a hydrostatic drive vehicle. The present invention can avoid the low-speed gear clutch from being triggered to disengage, keep the large-displacement motor in an engaged state, always provide a reverse drag torque, achieve a smooth and controllable downhill speed in the low-speed gear, ensure that the large-displacement motor operates within a safe speed range, and at the same time reduce the closing and disengagement frequency of the clutch, reduce the slippage of the clutch, and increase the service life of the clutch.

[0008] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions: In a first aspect, the present invention provides a driving control method for a hydrostatically driven vehicle, comprising: Get real-time status data of the vehicle; When it is determined, based on the real-time state data of the vehicle, that the vehicle is simultaneously in a low-speed gear, both motors are acting, and the vehicle speed exceeds the maximum speed set for the low-speed gear, the displacement of the high-displacement motor is adjusted so that the vehicle speed is within the set speed range, and the high-displacement motor remains engaged and always provides a counter-dragging torque.

[0009] Combined with the first aspect, optionally, adjusting the displacement of the high-displacement motor so that the vehicle speed is within the set speed range includes the following steps: Set the maximum vehicle speed when the vehicle is simultaneously in normal road driving, low-speed gear, and both motors acting as v1; Set the boundary vehicle speed at which the high-displacement motor is disengaged from the drive system as v2, that is, when the vehicle speed exceeds v2, control the clutch to disengage so that the high-displacement motor is disengaged from the drive system, v1 < v2, and the difference between v1 and v2 is less than the set threshold; Set the speed range [v1, v2], set the increase rate of the displacement of the high-displacement motor in this speed range as the first rate of change, and the first rate of change increases linearly with the vehicle speed range [v1, v2]; set the decrease rate of the displacement of the high-displacement motor in this speed range as the second rate of change, and the second rate of change is less than the first rate of change; Set the vehicle speed v4, v4 < v1, and the difference between v1 and v4 is less than the set threshold; When it is determined that the vehicle is simultaneously in a low-speed gear, both motors are acting, and the vehicle speed exceeds v1, adjust the displacement of the high-displacement motor according to the preset increase ratio A%; When the vehicle speed increases to v2, adjust the displacement of the high-displacement motor according to the preset increase ratio B%, quickly increase the counter-dragging torque, and reduce the vehicle speed so that the vehicle speed does not exceed v2, where B% > A%; When the vehicle speed is between v1 and v2, the increase ratio of the displacement of the high-displacement motor is found by looking up the table corresponding to the actual vehicle speed value between A% and B%; When the vehicle speed drops below v4, exit this adjustment process; When the vehicle speed exceeds v1 again, trigger the adjustment process again. Without active mechanical braking, regardless of the position of the accelerator pedal, for the vehicle speed exceeding v1 caused by the vehicle load in the downhill condition, the vehicle finally maintains the vehicle speed between v4 and v2 for downhill, then the clutch disengagement control will not be triggered, and the high-displacement motor remains engaged and always provides a counter-dragging torque.

[0010] Combined with the first aspect, optionally, the low-speed gear is determined through the following steps: Obtain the output signal of the gear button; Based on the output signal of the gear button, determine whether the vehicle is in a low-speed gear state or a high-speed gear state; The dual motor simultaneous action state is determined by the following steps: Obtaining an output signal of a pressure sensor at a clutch control cylinder port; Based on the output signal of the pressure sensor, it is determined whether the large-displacement motor is in an engaged or disengaged state. If the large-displacement motor is in an engaged state, it indicates that the vehicle is in a dual-motor action mode.

[0011] In combination with the first aspect, optionally, the drive control method further includes: Get the position information of the accelerator pedal; The engagement speed of the large displacement motor to the drive system is controlled according to the position information of the accelerator pedal, thereby reducing the frequency of the large displacement motor being engaged and disengaged from the drive system.

[0012] In combination with the first aspect, optionally, controlling the engagement speed of the large displacement motor to the drive system according to the position information of the accelerator pedal, thereby reducing the frequency of the large displacement motor being engaged and disengaged from the drive system, comprises the following steps: Set vehicle speed v5, v5<v1; Set vehicle speed v6, v6< <v5; When the vehicle is running at a high gear, or is reduced from a high gear to a low gear, if it is determined that the accelerator pedal position ratio exceeds the preset limit position, if the vehicle speed drops below v5, the clutch is controlled to close, so that the large displacement motor is engaged with the drive system; If it is determined that the accelerator pedal position ratio is lower than the preset limit position, the clutch is controlled to close after the vehicle speed drops below v6, so that the large-displacement motor engages with the drive system, otherwise the large-displacement motor is controlled to remain disengaged.

[0013] In combination with the first aspect, optionally, the extreme position is a 100% pedal position, a position exceeding a 90% pedal position, or a position exceeding an 80% pedal position.

[0014] In combination with the first aspect, optionally, the vehicle speed v6 is 0 km / h, less than 1 km / h, less than 2 km / h or less than 3 km / h.

[0015] In a second aspect, the present invention provides a drive control device for a hydrostatic drive vehicle, comprising: A vehicle real-time status data acquisition module, used to acquire the vehicle real-time status data; The first drive module is used to adjust the displacement of the large-displacement motor so that the vehicle speed is within the set speed range, and the large-displacement motor remains in an engaged state to always provide anti-drag torque when it is determined based on the real-time status data of the vehicle that the vehicle is in a low-speed gear at the same time, the dual motors are acting at the same time, and the vehicle speed exceeds the maximum speed set for the low-speed gear.

[0016] In combination with the second aspect, optionally, the drive control device further includes: An accelerator pedal position information acquisition module, used to acquire the accelerator pedal position information; The second driving module is used to control the engagement speed of the large displacement motor to the drive system according to the position information of the accelerator pedal, so as to reduce the frequency of the large displacement motor being engaged and disengaged from the drive system.

[0017] In a third aspect, the present invention provides a drive control system for a hydrostatic drive vehicle, comprising two motors of different displacements, wherein the larger displacement motor can be disengaged from or engaged with the drive system by controlling the disengagement and closing of the clutch; and comprising a master controller, which is used to operate according to the instructions to execute the method described in any one of the first aspects.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention aims at the problem that the vehicle stalls in the low-speed gear due to the increase in vehicle speed caused by the load of the vehicle in the low-speed gear and the active disengagement of the large-displacement motor. The downhill vehicle speed is actively controlled to avoid the low-speed gear clutch from being disengaged and triggered. The large-displacement motor remains in the meshing state and always provides the reverse drag torque, so that the low-speed gear downhill speed is stable and controllable, and the motor is ensured to work in a safe speed range. The present invention sets different motor engagement speeds according to the throttle position state, reduces the motor engagement frequency and engagement speed, and further reduces the motor disengagement frequency, thereby reducing the slip and heat generation during the clutch closing and disengagement process and increasing the clutch service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor, among which: Figure 1 The process of the driving control method of a hydrostatic drive vehicle according to an embodiment of the present invention is as follows: Figure 2 A schematic diagram of a driving control system for a hydrostatically driven vehicle according to an embodiment of the present invention; in: 1. Variable displacement pump; 2. Pump control valve; 3. Engine; 4. Engine controller; 5. Large displacement motor; 6. Large displacement motor displacement control valve; 7. Large displacement motor speed sensor; 8. Small displacement motor; 9. Small displacement motor speed sensor; 10. Small displacement motor displacement control valve; 11. Clutch control valve; 12. Pressure sensor; 13. Clutch control cylinder; 14. Clutch; 15. Accelerator pedal; 16. Shift button; 17. Master controller. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention. Example

[0022] In an embodiment of the present invention, a driving control method for a hydrostatically driven vehicle is provided. Figure 1 As shown, the following steps are included: (1) Obtain real-time status data of the vehicle; (2) When it is determined based on the real-time status data of the vehicle that the vehicle is in a low gear, the two motors are acting simultaneously, and the vehicle speed exceeds the maximum speed set for the low gear, the displacement of the large-displacement motor is adjusted so that the vehicle speed is within the set speed range, and the large-displacement motor remains in an engaged state to always provide a reverse torque.

[0023] In a specific implementation of the embodiment of the present invention, adjusting the displacement of the large-displacement motor so that the vehicle speed is within a set speed range includes the following steps: Set the maximum speed of the vehicle when it is driving on a normal road, in low gear and with dual motors working at the same time to v1; Set the boundary vehicle speed corresponding to the disconnection of the large-displacement motor from the drive system as v2, that is, when the vehicle speed exceeds v2, control the clutch to disengage so that the large-displacement motor is disconnected from the drive system, v1 < v2, and the difference between v1 and v2 is less than the set threshold; Set the speed range as [v1, v2], and set the increasing change rate of the displacement of the large-displacement motor in this speed range as the first change rate, and the first change rate increases linearly with the vehicle speed range [v1, v2]; set the decreasing change rate of the displacement of the large-displacement motor in this speed range as the second change rate, and the second change rate is less than the first change rate; Set the vehicle speed v4, v4 < v1, and the difference between v1 and v4 is less than the set threshold; When it is determined that the vehicle is simultaneously in a low gear, both motors are acting, and the vehicle speed exceeds v1, then adjust the displacement of the large-displacement motor according to the preset increase ratio A%; When the vehicle speed increases to v2, then adjust the displacement of the large-displacement motor according to the preset increase ratio B%, quickly increase the counter-dragging torque, reduce the vehicle speed, so that the vehicle speed does not exceed v2, where B% > A%; When the vehicle speed is between v1 and v2, the increase ratio of the displacement of the large-displacement motor is determined according to the actual vehicle speed value by looking up the table between A% and B%; When the vehicle speed drops below v4, then exit this adjustment process; When the vehicle speed exceeds v1 again, then trigger the adjustment process again. Without active mechanical braking, regardless of the position of the accelerator pedal, for the vehicle speed exceeding v1 caused by the vehicle load in the downhill condition, the vehicle finally maintains the vehicle speed between v4 and v2 for downhill, then the clutch disengagement control will not be triggered, and the large-displacement motor remains engaged and always Provides a counter-dragging torque.

[0024] In a specific implementation manner of the embodiment of the present invention, the low gear is determined through the following steps: Obtain the output signal of the gear button; Based on the output signal of the gear button, determine whether the vehicle is in a low gear state or a high gear state; The state where both motors act simultaneously is determined through the following steps: Obtain the output signal of the pressure sensor at the clutch control cylinder port; Based on the output signal of the pressure sensor, determine whether the large-displacement motor is in an engaged or disengaged state. If the large-displacement motor is in an engaged state, it means that the vehicle is in a dual-motor action mode.

[0025] In a specific implementation manner of the embodiment of the present invention, the drive control method further includes: Obtain the position information of the accelerator pedal; The engagement speed of the large displacement motor to the drive system is controlled according to the position information of the accelerator pedal, thereby reducing the frequency of the large displacement motor being engaged and disengaged from the drive system.

[0026] In a specific implementation of the embodiment of the present invention, controlling the engagement speed of the large-displacement motor to the drive system according to the position information of the accelerator pedal, thereby reducing the frequency of the large-displacement motor being disengaged from the drive system, comprises the following steps: Set vehicle speed v5, v5<v1; Set vehicle speed v6, v6< <v5; When the vehicle is running at a high gear, or is reduced from a high gear to a low gear, if it is determined that the accelerator pedal position ratio exceeds the preset limit position, if the vehicle speed drops below v5, the clutch is controlled to close so that the large displacement motor is engaged with the drive system, otherwise the large displacement motor is controlled to remain disengaged; If it is determined that the accelerator pedal position ratio is lower than the preset limit position, the clutch is controlled to close after the vehicle speed drops below v6, so that the large-displacement motor engages with the drive system, otherwise the large-displacement motor is controlled to remain disengaged.

[0027] In a specific implementation of the embodiment of the present invention, the extreme position is the 100% position of the pedal, exceeds the 90% position of the pedal, or exceeds the 80% position of the pedal, which can be set according to actual conditions.

[0028] In a specific implementation of the embodiment of the present invention, the vehicle speed v6 is 0 km / h, less than 1 km / h, less than 2 km / h or less than 3 km / h, and can be set according to actual conditions. Example

[0029] Based on the same inventive concept as that of Embodiment 1, a drive control device for a hydrostatically driven vehicle is provided in an embodiment of the present invention, comprising: A vehicle real-time status data acquisition module, used to acquire the vehicle real-time status data; The first drive module is used to adjust the displacement of the large-displacement motor so that the vehicle speed is within the set speed range, and the large-displacement motor remains in an engaged state to always provide anti-drag torque when it is determined based on the real-time status data of the vehicle that the vehicle is in a low-speed gear at the same time, the dual motors are acting at the same time, and the vehicle speed exceeds the maximum speed set for the low-speed gear.

[0030] In a specific implementation of the embodiment of the present invention, the drive control device further includes: An accelerator pedal position information acquisition module, used to acquire the accelerator pedal position information; The second driving module is used to control the engagement speed of the large displacement motor to the drive system according to the position information of the accelerator pedal, so as to reduce the frequency of the large displacement motor being engaged and disengaged from the drive system. Example

[0031] In an embodiment of the present invention, a driving control system for a hydrostatically driven vehicle is provided, such as Figure 2 As shown, the hydrostatic drive vehicle includes a variable pump 1, a pump control valve 2, an engine 3, an engine controller 4, a large displacement motor 5, a large displacement motor displacement control valve 6, a large displacement motor speed sensor 7, a small displacement motor 8, a small displacement motor speed sensor 9, a small displacement motor displacement control valve 10, a clutch control valve 11, a clutch 14, a clutch control cylinder 13, a pressure sensor 12 at the port of the clutch control cylinder 13, an accelerator pedal 15, a gear button 16, a transfer case and a master controller 17, wherein the master controller 17 is used to operate according to the instructions to perform the method according to any one of the embodiments 1. The variable pump 1, the engine 3, the large displacement motor 5, the small displacement motor 8 and the transfer case constitute a drive system.

[0032] Figure 1The schematic diagram of the driving control system of a hydrostatically driven vehicle in one embodiment of the present invention. The input shaft of the variable pump 1 is directly connected to the output shaft of the engine 3, and the two oil ports of the variable pump 1 are directly connected to the two oil port pipelines of the large displacement motor 5 and the small displacement motor 8 at the same time. The output shaft of the large displacement motor 5 is rigidly connected to the input shaft 1 of the transfer case through a spline, and the output shaft of the small displacement motor 8 is rigidly connected to the input shaft 2 of the transfer case through a spline. A common output shaft is formed through gear transmission (that is, the power of the two motors is transmitted to the common output shaft through gear transmission) to drive the vehicle, and between the output shaft of the large displacement motor 5 and the output shaft of the transfer case A clutch 14 is provided to realize the disengagement and engagement of the large displacement motor (if the large displacement motor is disengaged from the clutch in the transfer case, power will no longer be transmitted to the common output shaft). A large displacement motor speed sensor 7 and a small displacement motor speed sensor 9 are provided on the output shafts of the large displacement motor 5 and the small displacement motor 8 to detect the actual speeds of the large displacement motor and the small displacement motor, and the vehicle speed can be calculated according to the transmission ratio and the wheel diameter (speed / transfer case transmission ratio / axle transmission ratio*wheel diameter). The input end of the master controller 17 is connected to the accelerator pedal signal 15 and the gear position. The main controller 17 is connected to the button 16, and at the same time, the engine speed request is made to the engine controller 4 through the CAN bus communication and the actual engine speed information of the engine controller 4 is received. At the same time, the output end of the main controller 17 is connected to the pump control valve 2, the large displacement motor displacement control valve 6 and the small displacement motor displacement control valve 10. The displacement control of the variable pump and the variable motor is realized by setting different currents. At the same time, the output end of the main controller 17 is connected to the clutch control valve 11, and the hydraulic oil enters the clutch control cylinder through the clutch control valve 11. The clutch control cylinder 13 moves under the action of the spring and the hydraulic oil, driving the clutch plate to be pressed or separated, and the large displacement motor 5 is thereby engaged to the drive system or disengaged from the drive system, which determines whether the large displacement motor 5 is in effect. The main controller 17 controls the hydraulic oil to the clutch control cylinder 13, and a pressure sensor 12 is set at the inlet of the clutch control cylinder 13. The output signal of the pressure sensor 12 is connected to the input end of the main controller 17, which is used to judge the clutch separation or closing state, thereby judging whether the large displacement motor is disengaged or engaged.

[0033] How it works: Under normal conditions, the master controller 17 controls the clutch control valve 11 to be energized, and hydraulic oil enters the clutch control cylinder 13 to close the clutch 14. The master controller 17 detects the pressure through the pressure sensor signal 12 and confirms that the clutch is in the closed state (i.e., the clutch plates are pressed together) based on the pressure value. At this time, the high-displacement motor 5 engages with the drive system for power output. The hydraulic oil from the hydraulic pump 1 simultaneously flows to the high-displacement motor 5 and the low-displacement motor 8 to meet the operation requirement of high torque. When the master controller 17 controls the clutch control valve 11 to lose power, the hydraulic oil in the clutch control cylinder 13 is unloaded, and the clutch 14 disengages (i.e., the clutch plates separate). The master controller 17 detects the pressure value through the pressure sensor 12 to confirm that the clutch is in the disengaged state, so that the high-displacement motor 5 disengages from the drive system. The hydraulic pump 1 outputs all the hydraulic oil only to the low-displacement motor 8 to meet the requirement of high-speed driving.

[0034] The throttle pedal position ranges from the normal position of 0% to the lowest position of 100%, representing the engine speed request from the engine idle speed to the engine maximum speed. Under normal conditions, the hydrostatic vehicle can achieve stepless speed regulation. However, to adapt to the actual operation conditions, a low-speed gear is usually set for digging operations, and a high-speed gear is set for traveling and transfer operations. The master controller 17 realizes the switching between the low-speed gear and the high-speed gear according to the trigger of the gear button 16. That is, when the vehicle is driving on a normal road surface (i.e., flat road driving), in the low-speed gear and the state where both motors are acting, when the throttle pedal is at the 100% position, the maximum vehicle speed is set to v1. To prevent the high-displacement motor from overspeed, when its speed exceeds the speed limit range value, the high-displacement motor needs to be actively disengaged. The boundary vehicle speed corresponding to the disengagement of the high-displacement motor from the drive system is set to v2. That is, when the vehicle speed exceeds v2, the clutch is controlled to disengage so that the high-displacement motor disengages from the drive system, and v1 < v2. When driving on a road surface in the high-speed gear, when the throttle pedal is at the 100% position, the maximum vehicle speed is set to v3. The change in vehicle speed is formed by the combined control of the engine speed, pump displacement, and motor displacement changes.

[0035] When the vehicle is traveling at a low gear on a flat road, the main controller 17 controls the clutch control valve 11 to be energized, and the large-displacement motor 5 is in a meshing state. When the accelerator pedal 15 is stepped on to the 100% position, the maximum vehicle speed reaches v1. When the upshift button in the gear button 16 is triggered, it is a high gear. The main controller 17 controls the displacement of the large-displacement motor 5 to decrease. When the vehicle speed increases to more than v2, the main controller 17 controls the displacement of the large-displacement motor 5 to return to zero and controls the clutch control valve 11 to lose power. The large-displacement motor 5 is disengaged from the drive system, and the vehicle accelerates, and finally travels at a high-speed gear and a speed corresponding to the accelerator pedal position. When the vehicle is in a low gear and with a small oil pressure, the clutch control valve 11 is de-energized, and the large-displacement motor 5 is disengaged from the drive system. When the door pedal is in working position, the vehicle speed is low, the large-displacement motor works at a relatively large displacement, and the anti-drag torque is large, so the vehicle speed remains stable, the vehicle load will not cause the vehicle speed to increase, and the speed is controllable. When the accelerator pedal is in a low-speed gear and the vehicle is in a large proportion downhill, the vehicle goes downhill at a higher speed, the large-displacement motor works at a relatively small displacement, and the anti-drag torque is weakened. Because of the load of the vehicle itself, the vehicle speed gradually increases. When the vehicle speed exceeds v2, the large-displacement motor 5 is triggered to actively disengage, and only the small-displacement motor 8 works. The anti-drag torque of the whole vehicle is further reduced, and the vehicle speed further increases suddenly. The speed is uncontrollable, which is easy to cause safety problems. To solve this problem, the present invention proposes: The maximum speed when the vehicle is in normal road driving, low gear and dual motors are in action is set as v1, and the boundary speed corresponding to the large displacement motor 5 being disengaged is set as v2, the speed of v1 is less than the speed of v2, and the difference between v1 and v2 is less than the set threshold, which can be set to 1km / h or 2km / h. The difference between the two can be set according to the actual situation. In the specific implementation process, the main controller 17 can detect the gear button 16 to determine whether it is in the low gear state, and the main controller 17 can determine the dual motor action mode according to the pressure sensor 12. A speed interval [v1, v2] is set, and the rate of increase of the displacement of the large-displacement motor within the speed interval is set to a first rate of change, and the first rate of change increases linearly with the vehicle speed interval [v1, v2] to control the displacement of the large-displacement motor to increase rapidly, so as to quickly increase the anti-drag torque and reduce the speed. The rate of decrease of the displacement of the large-displacement motor within the speed interval is set to a second rate of change, and the second rate of change is smaller than the first rate of change, so as to control the displacement of the large-displacement motor to decrease slowly and the vehicle speed no longer increases rapidly.

[0036] When it is determined that the vehicle is in a low gear at the same time, the two motors are working at the same time, and the vehicle speed exceeds v1, the displacement of the large-displacement motor is adjusted according to the preset increase ratio A%; when the vehicle speed increases to v2, the displacement of the large-displacement motor is adjusted according to the preset increase ratio B%, where B%>A%; when the vehicle speed is between v1 and v2, the displacement increase ratio of the large-displacement motor is based on the actual value of the vehicle speed and is corresponding to the value between A% and B%; when the vehicle speed drops to less than v1, the vehicle speed is set to v4, v4<v1, the difference between v1 and v4 is less than the set threshold, which can be set to 1km / h, and the size of the difference between the two can be set according to the actual situation. When the vehicle speed drops to less than v1, the vehicle speed is set to v4, v4<v1, and the difference between v1 and v4 is less than the set threshold, which can be set to 1km / h. The size of the difference between the two can be set according to the actual situation. v4, then the adjustment process is exited. When the vehicle speed exceeds v1 again, the adjustment is triggered again. Without active mechanical braking, no matter the position of the accelerator pedal, or whether it is fully released at 0% or fully depressed at 100%, for downhill conditions, the vehicle speed exceeds v1 due to the vehicle load, and the vehicle speed finally remains between v4 and v2. The clutch disengagement control will not be triggered, and the large-displacement motor will remain engaged, always providing reverse torque, thereby avoiding the problem of vehicle stalling caused by the active disengagement of the large-displacement motor when the vehicle is downhill in the low-speed gear dual-motor mode. This ensures smooth control of the vehicle's downhill speed.

[0037] When the vehicle is running in a high-speed gear or switching from a high-speed gear to a low-speed gear, the vehicle is decelerated and the vehicle speed v5 is set, v5<v1. When the main controller 17 detects that the vehicle speed is less than v5, the clutch control valve 11 is controlled to be energized, and the clutch is closed to make the large-displacement motor engage with the drive system, and according to the information of the pressure sensor 12, it is determined whether the large-displacement motor is engaged. However, when the vehicle is accelerated again, when the vehicle speed exceeds v2, the large-displacement motor 5 is disengaged again. When the driving process repeatedly accelerates and decelerates, it is necessary to control the large-displacement motor to be frequently disengaged and engaged from the drive system, so it is necessary to control the clutch to disengage and close, causing slippage. Frequent slippage reduces the life of the clutch. To avoid this phenomenon, the present invention proposes: The vehicle speed v6 is set, and v6 is much smaller than v5, and can be preferably set to 0 km / h, or can be preferably set to 1 km / h, or can be preferably set to 2 km / h, or can be preferably set to 3 km / h. The main controller 17 obtains the accelerator pedal electrical signal, and converts it into the accelerator pedal position ratio according to the set increase / decrease rate. When the main controller determines that the accelerator pedal position ratio exceeds the limit position, the limit position can be preferably set to the 100% position of the pedal, or can be preferably set to exceed the 90% position of the pedal, or can be preferably set to exceed the 80% position of the pedal, then the engagement speed of the large-displacement motor is set to v5, that is, when the vehicle speed drops below v5, the clutch is controlled to close, so that the large-displacement motor is engaged to the drive If the main controller determines that the accelerator pedal position ratio is lower than the preset limit position, the engagement speed of the large-displacement motor is set to v6, that is, when the vehicle speed drops below v6, the clutch is controlled to close so that the large-displacement motor is engaged with the drive system. Otherwise, the large-displacement motor is controlled to remain in a disengaged state. Even if the accelerator pedal is released to a smaller position and the vehicle speed is reduced, if the vehicle speed is still greater than v6, it will still not engage. If the accelerator pedal is pressed again to accelerate, the large-displacement motor is in a disengaged state because it is not engaged. When the vehicle speed exceeds v2, there is no need to control the clutch to disengage the large-displacement motor, thereby reducing the clutch disengagement and closing frequency, reducing clutch slippage, and thereby increasing the clutch service life.

[0038] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0039] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0040] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0041] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0042] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

[0043] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A driving control method for a hydrostatically driven vehicle, characterized in that: Including: Obtain the real-time status data of the vehicle; When it is determined based on the real-time status data of the vehicle that the vehicle is simultaneously in a low gear, both motors are acting simultaneously, and the vehicle speed exceeds the maximum speed set for the low gear, then adjust the displacement of the large-displacement motor so that the vehicle speed is within the set speed range, and the large-displacement motor remains engaged and always provides a counter-dragging torque.

2. The driving control method of a hydrostatic drive vehicle according to claim 1, characterized in that: The adjusting the displacement of the large-displacement motor so that the vehicle speed is within the set speed range includes the following steps: Set the maximum vehicle speed when the vehicle is simultaneously in the normal road surface driving, low gear, and both motors acting simultaneously as v1; Set the boundary vehicle speed corresponding to the disengagement of the large-displacement motor from the drive system as v2, that is, when the vehicle speed exceeds v2, control the clutch to disengage so that the large-displacement motor disengages from the drive system, v1 < v2, and the difference between v1 and v2 is less than the set threshold; Set the speed range [v1, v2], set the increasing change rate of the displacement of the large-displacement motor in this speed range as the first change rate, and the first change rate increases linearly with the vehicle speed range [v1, v2]; set the decreasing change rate of the displacement of the large-displacement motor in this speed range as the second change rate, and the second change rate is less than the first change rate; Set the vehicle speed v4, v4 < v1, and the difference between v1 and v4 is less than the set threshold; When it is determined that the vehicle is simultaneously in a low gear, both motors are acting simultaneously, and the vehicle speed exceeds v1, then adjust the displacement of the large-displacement motor according to the preset increasing ratio A%; When the vehicle speed increases to v2, then adjust the displacement of the large-displacement motor according to the preset increasing ratio B%, quickly increase the counter-dragging torque, and reduce the vehicle speed so that the vehicle speed does not exceed v2, where B% > A%; When the vehicle speed is between v1 and v2, the increasing ratio of the displacement of the large-displacement motor is found according to the actual vehicle speed value from the table corresponding to the values between A% and B%; When the vehicle speed drops below v4, then exit this adjustment process; When the vehicle speed exceeds v1 again, then trigger the adjustment process again. Without active mechanical braking, regardless of the position of the accelerator pedal, for the vehicle speed exceeding v1 caused by the vehicle load in the downhill condition, the vehicle finally maintains the vehicle speed between v4 and v2 during downhill, then the clutch disengagement control will not be triggered, and the large-displacement motor remains engaged and always provides a counter-dragging torque.

3. The driving control method of a hydrostatic drive vehicle according to claim 1, characterized in that: The low gear is determined through the following steps: Obtain the output signal of the gear button; Determine whether the vehicle is in the low gear state or the high gear state based on the output signal of the gear button; The state of both motors acting simultaneously is determined through the following steps: Obtain the output signal of the pressure sensor at the clutch control cylinder port; Determine whether the large-displacement motor is engaged or disengaged based on the output signal of the pressure sensor. If the large-displacement motor is in the engaged state, it means the vehicle is in the dual-motor action mode.

4. The driving control method of a hydrostatic drive vehicle according to claim 1, characterized in that: The drive control method further includes: Obtain the position information of the accelerator pedal; Control the engagement vehicle speed of the large-displacement motor to the drive system according to the position information of the accelerator pedal, thereby reducing the frequency of the large-displacement motor disengaging from the drive system.

5. The driving control method of a hydrostatic drive vehicle according to claim 4, characterized in that: Controlling the engagement speed of the large displacement motor to the drive system according to the position information of the accelerator pedal, thereby reducing the frequency of the large displacement motor being engaged and disengaged from the drive system, comprises the following steps: Set vehicle speed v5, v5<v1; Set vehicle speed v6, v6< <v5; When the vehicle is running at a high gear, or is driving from a high gear to a low gear, if it is determined that the accelerator pedal position ratio exceeds the preset limit position, if the vehicle speed drops below v5, the clutch is controlled to close, so that the large-displacement motor is engaged with the drive system; If it is determined that the accelerator pedal position ratio is lower than the preset limit position, the clutch is controlled to close after the vehicle speed drops below v6, so that the large-displacement motor engages with the drive system, otherwise the large-displacement motor is controlled to remain disengaged.

6. The driving control method of a hydrostatic drive vehicle according to claim 5, characterized in that: The extreme position is the 100% pedal position, a position exceeding 90% pedal position, or a position exceeding 80% pedal position.

7. The driving control method of a hydrostatic drive vehicle according to claim 5, characterized in that: The vehicle speed v6 is 0 km / h, less than 1 km / h, less than 2 km / h or less than 3 km / h.

8. A drive control device for a hydrostatic drive vehicle, characterized in that: include: A vehicle real-time status data acquisition module, used to acquire the vehicle real-time status data; The first drive module is used to adjust the displacement of the large-displacement motor so that the vehicle speed is within the set speed range, and the large-displacement motor remains in an engaged state to always provide anti-drag torque when it is determined based on the real-time status data of the vehicle that the vehicle is in a low-speed gear at the same time, the dual motors are acting at the same time, and the vehicle speed exceeds the maximum speed set for the low-speed gear.

9. The driving control device for a hydrostatically driven vehicle according to claim 8, characterized in that: The drive control device also includes: An accelerator pedal position information acquisition module, used to acquire the accelerator pedal position information; The second driving module is used to control the engagement speed of the large displacement motor to the drive system according to the position information of the accelerator pedal, so as to reduce the frequency of the large displacement motor being engaged and disengaged from the drive system.

10. A drive control system for a hydrostatic drive vehicle, characterized in that: It comprises two motors of different displacements, wherein the larger displacement motor can be disengaged from or engaged with the drive system by controlling the disengagement and closure of the clutch; it comprises a master controller, which is used to operate according to the instructions to execute the method according to any one of claims 1-7.

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