A vehicle control method and control system

Abstract

This application provides a vehicle control method and control system. The control method includes: if the lifting equipment is in a hoisting condition, determining whether to perform a limit speed calculation; if so, monitoring the hydraulic pump pressure to obtain the calculation start time, and controlling the engine speed to rise to a first set speed from the calculation start time; obtaining a first variable; and comparing the first variable with the set variable to obtain the limit speed. The first variable is the change in hydraulic pump pressure per unit rotation of the engine. Therefore, this control method obtains the limit speed by monitoring the change in hydraulic pump pressure. Knowing that this limit speed is the highest engine speed during the current hoisting operation to avoid pressure loss, this control method obtains the highest engine speed corresponding to the current hoisting condition of the lifting equipment, providing a reliable basis for adjusting the engine speed during hoisting, effectively protecting the vehicle and reducing hoisting costs.

Description

Technical Field

[0001] This application relates to the field of crane technology, and more particularly to a vehicle control method and control system. Background Technology

[0002] A truck crane is a lifting device mounted on a specially designed truck chassis. The engine is connected to a hydraulic pump in the hydraulic system. When working, the hydraulic pump generates high-pressure oil to drive different hydraulic components of the vehicle to achieve different lifting actions, such as winching, luffing, and telescopic boom.

[0003] During lifting operations, the vehicle uses remote throttle control to adjust engine speed for different lifting actions. However, different lifting actions require different engine speeds, and the vehicle cannot distinguish the required engine speed for each action. Therefore, to ensure that the engine speed meets the needs of each lifting action, the vehicle sets the maximum remote throttle speed of the engine to a relatively high level, such as 2000 rpm.

[0004] Because the engine and hydraulic pump are mechanically connected, the engine speed and the hydraulic pump speed maintain a specific proportional relationship. When a certain lifting action requires a small hydraulic system flow rate and the engine speed is high, the hydraulic system output flow rate will be greater than the hydraulic main valve's limiting flow rate. This means that once the engine speed reaches the required speed, even if the engine speed is further increased, the overall vehicle movement rate will not increase. Instead, it will cause problems such as high engine fuel consumption and overheating of the vehicle's hydraulic system. Summary of the Invention

[0005] In view of this, this application provides a vehicle control method, the scheme of which is as follows:

[0006] A vehicle control method for a vehicle including a lifting device connected to an engine via a hydraulic pump, the control method comprising:

[0007] Determine whether the lifting equipment is in a hoisting condition;

[0008] If so, determine whether to calculate the limit speed, where the limit speed is the maximum engine speed that satisfies the current lifting action of the lifting equipment;

[0009] If so, then the limit speed is calculated, and the calculation of the limit speed includes:

[0010] Monitor the hydraulic pump pressure and determine the calculation start time based on the change in the hydraulic pump pressure;

[0011] Starting from the calculation start time, control the engine speed to increase to the first set speed;

[0012] During the process of the engine speed rising to the first set speed, a first variable is obtained, which is the change in hydraulic pump pressure per unit number of engine rotations;

[0013] The set variable of the hydraulic pump pressure is called, and the first variable is compared with the set variable to obtain the limit speed, which is the engine speed when the first variable is equal to the set variable for the first time;

[0014] After calculating the limit speed, the limit speed is set as the maximum engine speed of the lifting equipment during the current lifting operation.

[0015] Optionally, monitoring the hydraulic pump pressure and determining the calculation start time based on the change in the hydraulic pump pressure includes:

[0016] Monitor the hydraulic pump pressure. When the hydraulic pump pressure is greater than the first set pressure, obtain a second variable, which is the change in hydraulic pump pressure over time.

[0017] The calculation start time is obtained based on the second variable, which is the moment when the second variable first becomes less than a first preset value.

[0018] Optionally, determining whether to calculate the limit speed includes:

[0019] Determine whether the engine speed is greater than or equal to the second preset speed and whether the duration exceeds the first preset time;

[0020] Determine whether the engine output torque is greater than or equal to a set torque, and whether the duration exceeds a second preset time;

[0021] Determine whether the hydraulic pump pressure is greater than or equal to the second set pressure, and whether the duration exceeds the second preset time;

[0022] The second set pressure is less than the first set pressure.

[0023] Optionally, the control method further includes:

[0024] Determine whether the current lifting operation of the lifting equipment has ended;

[0025] The determination of whether the current lifting action of the lifting equipment has ended includes:

[0026] If the hydraulic pump pressure rises from the second set pressure to the first set pressure and then drops back to the second set pressure, it is determined that the current lifting operation of the lifting equipment has ended.

[0027] Optionally, the control method further includes:

[0028] During the calculation of the limit speed, a third variable is obtained, which is the change in hydraulic pump pressure every third preset time interval;

[0029] If the third variable is greater than or equal to the second set value, and the hydraulic pump pressure is always greater than the first set pressure, then the calculation of the limit speed is terminated.

[0030] Then, the maximum speed of the engine is reset to the original maximum speed, which is the maximum speed set when the vehicle leaves the factory.

[0031] Optionally, the control method further includes:

[0032] After calculating the limit speed, during the current lifting operation of the lifting equipment, a fourth variable is obtained, which is the change in hydraulic pump pressure every fourth preset time interval;

[0033] If the fourth variable is greater than or equal to the third set value, and the hydraulic pump pressure is always greater than the first set pressure, then the calculation of the limit speed is terminated.

[0034] Then, the maximum speed of the engine is reset to the original maximum speed, which is the maximum speed set when the vehicle leaves the factory.

[0035] A control system for controlling the lifting equipment of a vehicle, the control system comprising:

[0036] The first judgment module is used to determine whether the lifting equipment is in a hoisting condition.

[0037] The second judgment module is used to determine whether to calculate the limit speed.

[0038] The monitoring module is used to monitor the pressure of the hydraulic pump;

[0039] During the limitation calculation, the first control unit controls the engine speed to rise to a first set speed and acquires a first variable, which is the change in hydraulic pump pressure per unit number of engine revolutions.

[0040] The first control unit is also used to call the set variable of the hydraulic pump pressure corresponding to the current lifting action of the lifting equipment, and compare the first variable with the set variable to obtain the limit speed, wherein the limit speed is the engine speed when the first variable is equal to the set variable for the first time;

[0041] After calculating the limit speed, the adjustment unit sets the limit speed to the maximum speed of the engine when performing the current hoisting operation.

[0042] Optionally, the control system further includes a third judgment module, which is used to determine whether the current lifting action of the lifting equipment has ended;

[0043] If the hydraulic pump pressure rises from the second set pressure to the first set pressure and then drops back to the second set pressure, the third judgment module determines that the current hoisting action of the lifting equipment has ended.

[0044] Optionally, the control system further includes a second control unit, which is used to obtain a third variable during the calculation of the limit speed, the third variable being the change in hydraulic pump pressure at a third preset time interval;

[0045] If the monitoring module detects that the third variable is greater than or equal to the second set value, and the hydraulic pump pressure is always greater than the first set pressure, then the second control unit terminates the calculation of the limit speed.

[0046] Subsequently, the adjustment unit is also used to reset the maximum speed of the engine to the original maximum speed, which is the maximum speed set when the vehicle leaves the factory.

[0047] Optionally, the control system further includes a third control unit. After calculating the limit speed, during the current hoisting operation of the lifting equipment, the third control unit is used to acquire a fourth variable, which is the change in hydraulic pump pressure every fourth preset time interval.

[0048] If the first monitoring unit detects that the fourth variable is greater than or equal to the third set value, and the hydraulic pump pressure is always greater than the first set pressure, the third control unit is also used to terminate the calculation of the limit speed.

[0049] Subsequently, the adjustment unit is also used to reset the maximum speed of the engine to the original maximum speed, which is the maximum speed set when the vehicle leaves the factory.

[0050] Compared with existing technologies, the beneficial effects of the technical solution provided in this application are as follows:

[0051] The control method provided in this application includes: if the lifting equipment is in a hoisting condition, determining whether to perform a limit speed calculation; if so, monitoring the hydraulic pump pressure to obtain the calculation start time, and controlling the engine speed to rise to a first set speed from the calculation start time; during the engine speed rise, acquiring a first variable, and comparing the first variable with the set variable to obtain the limit speed, wherein the first variable is the hydraulic pump pressure variable per unit rotation of the engine. Therefore, this control method obtains the limit speed by monitoring changes in the hydraulic pump pressure and sets this limit speed as the maximum engine speed for the current hoisting operation. Knowing that this limit speed is the maximum engine speed to avoid pressure loss during the current hoisting operation, this control method obtains the maximum engine speed corresponding to the current hoisting condition of the lifting equipment, providing a reliable basis for adjusting the engine speed during hoisting. This allows for minimizing excessively high engine speeds during hoisting operations, thereby avoiding problems such as high engine fuel consumption and overheating of the vehicle's hydraulic system, effectively protecting the vehicle and reducing hoisting costs. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0053] The structures, proportions, sizes, etc., shown in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0054] Figure 1 A flowchart of a vehicle control method provided in this application;

[0055] Figure 2 A flowchart of another vehicle control method provided in this application;

[0056] Figure 3 This is the pressure change curve of the hydraulic pump;

[0057] Figure 4 The curves showing the changes of the first variable and the set variable;

[0058] Figure 5 This is a hydraulic pump pressure change curve during a compound action.

[0059] Figure 6 This is a hydraulic pump pressure change curve when another compound action occurs. Detailed Implementation

[0060] The embodiments of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely one area of ​​this application, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0061] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0062] As described in the background section, since different lifting operations of a crane require different engine speeds, and the vehicle cannot distinguish the engine speed corresponding to each lifting operation, in order to ensure that the engine speed can meet the requirements of each lifting operation, the vehicle sets the maximum remote throttle speed of the engine to a relatively high speed. As a result, if a certain lifting operation requires a small hydraulic system flow, the engine speed is high, but the vehicle's operating speed will not increase. Instead, it will cause problems such as high engine fuel consumption and overheating of the vehicle's hydraulic system.

[0063] Based on this, this application provides a vehicle control method, wherein the vehicle includes lifting equipment, the lifting equipment being connected to an engine via a hydraulic pump. Figure 1 As shown, Figure 1 A flowchart of a vehicle control method provided in this application is included, the control method comprising:

[0064] S1: Determine whether the lifting equipment is in hoisting condition.

[0065] S2: If yes, determine whether to calculate the limit speed, where the limit speed is the maximum engine speed that satisfies the current lifting action of the lifting equipment;

[0066] S3: If so, then calculate the aforementioned limit speed, where, for example... Figure 2 As shown, Figure 2 A flowchart of a vehicle control method provided in this application shows that calculating the limit speed includes:

[0067] S31: Monitor the hydraulic pump pressure and determine the calculation start time based on the change in the hydraulic pump pressure, wherein the hydraulic pump pressure refers to the output pressure of the hydraulic pump. It should be noted that, as... Figure 3 As shown, Figure 3This is a graph showing the change in hydraulic pump pressure during the lifting operation. Figure 3 In the diagram, line segment 001 represents the first stage of the current lifting operation, line segment 002 represents the second stage, and line segment 003 represents the third stage. P 1x This represents the hydraulic pump pressure. The first stage is the waiting stage, which can be understood as the process of placing the object to be lifted onto the lifting equipment. The second stage is the preparation stage, which can be understood as the process of the hydraulic pump pressure gradually increasing to meet the lifting power requirements. The third stage is the lifting stage, which can be understood as the lifting process itself. According to... Figure 3 It is known that the lifting of the object only begins after the hydraulic pump pressure meets the lifting requirements. Furthermore, the aforementioned limit speed is the highest engine speed corresponding to the lifting phase of the current lifting operation. Therefore, the calculation of this limit speed should be performed during the lifting operation after the hydraulic pump pressure meets the lifting requirements. Thus, this control method determines the calculation start time based on the change in hydraulic pump pressure. Figure 3 t1 is the starting time of the calculation, which is to ensure that the limit speed is calculated during the hoisting process, so that the above limit speed can represent the maximum engine speed during the hoisting operation.

[0068] S32: Starting from the calculation start time, control the engine speed to increase to a first set speed. This application does not limit the specific value of the first set speed; it depends on the actual situation. It should be noted that although the specific value of the first set speed is not limited, it must be ensured that the first set speed is relatively high and less than the engine's original maximum speed. The original maximum speed refers to the maximum engine speed corresponding to the operation of the lifting equipment as set at the factory when the vehicle leaves the factory.

[0069] S33: During the process of the engine speed increasing to the first set speed, a first variable is obtained. The first variable is the change in hydraulic pump pressure per unit number of engine revolutions. For example, taking 100 engine revolutions as a calculation step, the first variable is the change in hydraulic pump pressure when the engine has rotated 100 times. Specifically, the first variable ΔP = P N+100 -P N N represents the number of revolutions the engine makes.

[0070] S34: After obtaining the first variable, the set variable of the hydraulic pump pressure is called, and the first variable is compared with the set variable to obtain the limit speed. The limit speed is the engine speed at which the first variable first equals the set variable, that is, the limit speed is the engine speed at which the change in hydraulic pump pressure caused by the change in engine speed first equals the set variable. Specifically, as shown... Figure 4 As shown, Figure 4 Curve 1 represents the change curve of the first variable, and curve 2 represents the change curve of the set variable. V1 is the aforementioned limit speed. It should be noted that the set variable for the hydraulic pump pressure is determined experimentally and stored in advance in the ECU. This set variable represents the limit for hydraulic pump pressure changes during lifting operations. Exceeding this limit indicates excessive pressure, which will result in pressure loss. Therefore, this limit speed is the highest engine speed that avoids pressure loss during the current lifting operation.

[0071] After calculating the limit speed, the control method further includes:

[0072] S4: Set the limit speed to the maximum engine speed of the lifting equipment during the current lifting operation, so as to keep the engine speed from exceeding the limit speed during the lifting operation.

[0073] Specifically, this control method obtains a limit speed by monitoring changes in hydraulic pump pressure and sets this limit speed as the maximum engine speed for the current lifting operation. As mentioned above, this limit speed is the maximum engine speed that avoids pressure loss during the current lifting operation. Therefore, this control method obtains the maximum engine speed corresponding to the current lifting condition, providing a reliable basis for adjusting the engine speed during lifting. This ensures that different lifting operations have their own corresponding maximum engine speed, thus achieving adaptive adjustment of the maximum engine speed for different lifting conditions. This minimizes excessive engine speed during each lifting operation, preventing problems such as high engine fuel consumption and overheating of the vehicle's hydraulic system, effectively protecting the vehicle and reducing lifting costs.

[0074] For step S31, in one embodiment of this application, monitoring the hydraulic pump pressure and determining the calculation start time based on the change in the hydraulic pump pressure includes:

[0075] Continue as Figure 3 As shown, the hydraulic pump pressure P is monitored. 1x When the hydraulic pump pressure P 1x After the pressure exceeds the first set pressure P1, the second variable ΔP is obtained. 1x The second variable ΔP 1x The hydraulic pump pressure P 1x The change over time. Specifically, the second variable ΔP is obtained. 1x The specific process is as follows: periodically obtain the hydraulic pump pressure P 1x That is, the hydraulic pump pressure P is obtained sequentially at regular intervals. 1x Calculate the difference between two consecutive hydraulic pump pressures to obtain the second variable ΔP mentioned above. 1xIt should be noted that this application pertains to obtaining the hydraulic pump pressure P. 1x The time interval is not limited and can be 1 second, 2 seconds, etc., depending on the actual situation. However, it is necessary to ensure that the second variable ΔP mentioned above is obtained. 1x The time intervals are the same. It should also be noted that hydraulic pump pressure can be monitored using devices such as pressure sensors, depending on the specific circumstances.

[0076] Obtain the second variable ΔP 1x Then, based on the second variable ΔP 1x The calculation start time t1 is obtained, and the calculation start time t1 is the second variable ΔP. 1x The moment when the value is first less than the first preset value ΔP1.

[0077] Specifically, as described above, this control method determines the start time of calculation when the first variable is less than the first preset value. In other words, this control method starts calculating the limit speed only after the hydraulic pump pressure stabilizes, thus avoiding the impact of hydraulic pump pressure fluctuations on the calculation accuracy and ensuring the accuracy of the calculation.

[0078] Based on the above embodiments, in one embodiment of this application, step S2, determining whether to calculate the limit speed, includes:

[0079] The system determines whether the engine speed is greater than or equal to a second preset speed, and whether the duration exceeds a first preset time; that is, whether the engine speed is not less than the second preset speed, and whether the duration exceeds the first preset time. The first preset time is a set value, which may vary depending on the specific circumstances.

[0080] Determine whether the engine output torque is greater than or equal to the set torque and the duration exceeds the second preset time, that is, determine whether the engine output torque is not less than the set torque and the duration exceeds the second preset time.

[0081] The system determines whether the hydraulic pump pressure is greater than or equal to the second set pressure P2, and whether the duration exceeds the second preset time; that is, whether the hydraulic pump pressure is not less than the second set pressure, and whether the duration exceeds the second preset time. The second set pressure is less than the second preset pressure.

[0082] As previously known, the lifting process of a hoisting device includes a waiting phase, a preparation phase, and a hoisting phase. During the waiting phase, the hydraulic pump pressure is also stable. To ensure that the calculation of the limit speed is performed in the subsequent hoisting phase, it is necessary to distinguish whether the current stage of stable hydraulic pump pressure is the waiting phase or the hoisting phase. According to... Figure 3It is known that the hydraulic pump pressure during the waiting phase is lower than that during the hoisting phase. Therefore, the current stage can be determined by analyzing engine speed, engine output torque, and hydraulic pump pressure. Specifically, if the hydraulic pump pressure is not less than the second set pressure P2, the engine speed is not less than the second set speed, and the engine output torque is not less than the set torque, it can be determined that the current stage is not a waiting phase, but rather a subsequent preparation or hoisting phase. Next, it needs to be determined whether it is the preparation or hoisting phase. Since the preparation phase is characterized by a short duration of hydraulic pump pressure increase, the duration for which the hydraulic pump pressure, engine speed, and engine output torque are not less than the second set pressure P2, are not less than the second set speed, and the engine output torque is not less than the set torque can be used to determine whether the current stage is the preparation or hoisting phase. If the duration exceeds a certain value, it indicates that the current stage is the hoisting phase. In summary, when the engine speed is greater than or equal to the second set speed and the duration exceeds the first preset time, the engine output torque is greater than or equal to the set torque and the duration exceeds the second preset time, and the hydraulic pump pressure is also greater than or equal to the second set pressure, it can be determined that the current stage is the hoisting phase, and the calculation of the limit speed can begin.

[0083] It should be noted that the limit speeds for different lifting actions are usually different. Therefore, the limit speed should be calculated for each lifting action, which requires determining whether the current lifting action has ended so that the limit speed can be recalculated before the next lifting action, thereby limiting the engine speed. Therefore, based on the above embodiments, in one embodiment of this application, the control method further includes:

[0084] S5: Determine whether the current hoisting action of the lifting equipment has ended.

[0085] The determination of whether the current lifting action of the lifting equipment has ended includes:

[0086] If the hydraulic pump pressure rises from the second set pressure to the first set pressure and then drops back to the second set pressure, that is, the hydraulic pump pressure changes from a lower value to a higher value and then drops back to a lower value, it indicates that the hoisting action has been completed, and thus it can be determined that the current hoisting action of the lifting equipment has ended.

[0087] The above embodiments describe cases where the lifting equipment performs a single hoisting action, such as simply lifting. However, if the current hoisting action of the lifting equipment is a compound action, that is, the current hoisting action includes multiple actions, such as lifting + rotation, the aforementioned speed limit will no longer apply in this case, and therefore, it is not necessary to calculate the speed limit. Therefore, based on the above embodiments, in one embodiment of this application, the control method includes:

[0088] S6: During the calculation of the limit speed, a third variable is obtained, which is the change in the hydraulic pump pressure at a third preset time interval.

[0089] If the third variable is greater than or equal to the second set value, and the hydraulic pump pressure is always greater than the first set pressure, then the calculation of the limit speed is terminated. It should be noted that if the third variable is greater than or equal to the second set value (i.e., the third variable is not less than the second set value), it indicates that the hydraulic pump pressure has changed significantly, which in turn indicates that the lifting equipment's operation has changed, thus the current lifting operation of the lifting equipment is a composite operation.

[0090] Then, the engine's maximum speed is set to the original maximum speed, which is the maximum speed set when the vehicle leaves the factory, to meet the power requirements of the compound operation. It should be noted that setting the engine's maximum speed to the original maximum speed refers to setting the engine speed corresponding to the operation of the lifting equipment to the original maximum speed.

[0091] The above embodiments describe a compound action occurring during the calculation of the limit speed; however, this compound action may also occur after the limit speed has been calculated. Therefore, in another embodiment of this application, the control method further includes:

[0092] S7: After calculating the limit speed, during the current hoisting operation of the lifting equipment, a fourth variable is obtained, which is the change in the hydraulic pump pressure every fourth preset time interval.

[0093] If the fourth variable is greater than or equal to the third set value, and the hydraulic pump pressure is always greater than the first set pressure, then the calculation of the limit speed is terminated.

[0094] Then, the engine's maximum speed is reset to the original maximum speed, which is the maximum speed set when the vehicle leaves the factory, to meet the power requirements of the compound action.

[0095] It should be noted that this application does not limit the specific values ​​of the second and third settings mentioned above, and they should be set according to the actual situation of the vehicle, such as model and type. However, it should be ensured that the second and third settings are much larger than the second variable. Furthermore, the third preset time and the fourth preset time are also set according to the actual situation, and this application does not limit them.

[0096] To better understand the changes in hydraulic pump pressure during compound actions, two specific examples are described below. For instance... Figure 5 As shown, during the hoisting process, the hydraulic pump pressure P 1xIf ΔP2 changes significantly, exceeding the set value (the third or fourth set value mentioned above), it indicates a change in the lifting action during the current lifting process, i.e., a compound action has occurred. At this point, the calculation of the limit speed is stopped. Furthermore, if this compound action occurs after the limit speed calculation, the limit speed restriction on engine speed is removed. After the hydraulic pump pressure change ΔP2, the final stable value of the hydraulic pump pressure depends on subsequent changes in power demand. If the power demand decreases, the stable value of the hydraulic pump pressure decreases. Figure 5 As shown; if the power demand increases, the stable value of the hydraulic pump pressure will increase, such as... Figure 6 As shown.

[0097] Accordingly, this application also provides a control system that controls a vehicle using the control method described in any of the above embodiments. The vehicle includes lifting equipment connected to an engine via a hydraulic pump. The control system includes:

[0098] The first judgment module is used to determine whether the lifting equipment is in the hoisting condition.

[0099] The second judgment module is used to determine whether to calculate the limit speed.

[0100] A monitoring module is provided to monitor the pressure of the hydraulic pump.

[0101] During the limitation calculation, the first control unit controls the engine speed to rise to a first set speed and acquires a first variable, which is the hydraulic pump pressure per unit rotation of the engine.

[0102] The first control unit is also used to call the set variable of the hydraulic pump pressure corresponding to the current lifting action of the lifting equipment, compare the first variable with the set variable, and obtain the limit speed, the limit speed being the engine speed when the first variable first equals the set variable.

[0103] After calculating the limit speed, the adjustment unit sets the limit speed to the maximum speed of the engine when performing the current hoisting operation.

[0104] As described above, the control system obtains the limit speed by monitoring changes in hydraulic pump pressure and sets this limit speed as the maximum engine speed for the current lifting operation. Knowing that this limit speed is the maximum engine speed to avoid pressure loss during the current lifting operation, the control system can obtain the maximum engine speed corresponding to the current lifting condition. This provides a reliable basis for adjusting the engine speed during lifting, thus minimizing excessive engine speed during lifting operations. This prevents problems such as high engine fuel consumption and overheating of the vehicle's hydraulic system, effectively protecting the vehicle and reducing lifting costs.

[0105] It should be noted that the limit speeds for different lifting actions are usually different. Therefore, the limit speed should be calculated for each lifting action, which requires determining whether the current lifting action has ended. This allows for recalculation of the limit speed before the next lifting action, thus limiting the engine speed. Therefore, in one embodiment of this application, the control system further includes a third judgment module, used to determine whether the current lifting action of the lifting equipment has ended. Specifically, if the monitoring module detects that the hydraulic pump pressure rises from the second set pressure to the first set pressure and then drops back to the second set pressure—that is, the hydraulic pump pressure changes from a lower value to a higher value and then back to a lower value—it indicates that the lifting action has been completed. Therefore, it can be determined that the current lifting action of the lifting equipment has ended, and the third judgment module can then determine that the current lifting action of the lifting equipment has ended.

[0106] The above embodiments describe situations where the lifting equipment performs a single hoisting action, such as simply lifting. However, if the current hoisting action of the lifting equipment is a compound action, i.e., the current hoisting action includes multiple actions, such as lifting + rotation, the aforementioned limit speed will no longer apply in this case, and therefore, it is not necessary to calculate the limit speed. Therefore, in one embodiment of this application, the control system further includes a second control unit. During the calculation of the limit speed, the second control unit is used to acquire a third variable, which is the change in the hydraulic pump pressure at a third preset time interval. If the monitoring module detects that the third variable is greater than or equal to a second set value, and the hydraulic pump pressure is always greater than the first set pressure, then the second control unit terminates the calculation of the limit speed. Afterward, the adjustment unit is also used to reset the maximum speed of the engine to the original maximum speed, which is the maximum speed set when the vehicle leaves the factory.

[0107] The above embodiments describe a compound action occurring during the calculation of the limit speed; however, this compound action may also occur after the limit speed has been calculated. Therefore, in another embodiment of this application, the control system further includes a third control unit. After the limit speed is calculated, during the current lifting operation of the lifting equipment, the third control unit is used to acquire a fourth variable, which is the change in hydraulic pump pressure at a fourth preset time interval. If the first monitoring unit detects that the fourth variable is greater than or equal to a third set value, and the hydraulic pump pressure is always greater than the first set pressure, the third control unit is also used to terminate the calculation of the limit speed. Afterwards, the adjustment unit is also used to reset the engine's maximum speed to the original maximum speed, which is the maximum speed set when the vehicle was manufactured.

[0108] In summary, this application provides a vehicle control method and control system. The control method includes: if the lifting equipment is in a hoisting condition, determining whether to perform a limit speed calculation; if so, monitoring the hydraulic pump pressure to obtain the calculation start time, and controlling the engine speed to rise to a first set speed from the calculation start time; during the engine speed rise, acquiring a first variable, and comparing the first variable with the set variable to obtain the limit speed, wherein the first variable is the hydraulic pump pressure variable per unit rotation of the engine. Therefore, this control method obtains the limit speed by monitoring changes in the hydraulic pump pressure and sets this limit speed as the maximum engine speed for the current hoisting operation. Knowing that this limit speed is the maximum engine speed to avoid pressure loss during the current hoisting operation, this control method obtains the maximum engine speed corresponding to the current hoisting condition of the lifting equipment, providing a reliable basis for adjusting the engine speed during hoisting. This allows for minimizing excessively high engine speeds during hoisting operations, thereby avoiding problems such as high engine fuel consumption and overheating of the vehicle's hydraulic system, effectively protecting the vehicle and reducing hoisting costs.

[0109] The various embodiments in this specification are described in a progressive, parallel, or combined manner. Each embodiment focuses on its differences from other embodiments, and similar or identical areas between embodiments can be referred to interchangeably. For the apparatuses disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and relevant details can be found in the description of the method area.

[0110] It should be noted that, in the description of this application, the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component centrally located at the same time.

[0111] It should also be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes the aforementioned element.

[0112] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A vehicle control method, characterized in that, The vehicle includes lifting equipment connected to an engine via a hydraulic pump, and the control method includes: Determine whether the lifting equipment is in a hoisting condition; If so, determine whether to calculate the limit speed, where the limit speed is the maximum speed of the engine that meets the requirements of the current lifting operation of the lifting equipment; If so, then the limit speed is calculated, and the calculation of the limit speed includes: Monitor the hydraulic pump pressure and determine the calculation start time based on the change in the hydraulic pump pressure; Starting from the calculation start time, the engine speed is controlled to increase to the first set speed; During the process of the engine speed increasing to the first set speed, a first variable is obtained, which is the change in hydraulic pump pressure per unit number of engine rotations; The set variable of the hydraulic pump pressure is called, and the first variable is compared with the set variable to obtain the limit speed. The limit speed is the engine speed when the first variable is equal to the set variable for the first time. After calculating the limit speed, the limit speed is set as the maximum speed of the engine when the lifting equipment is performing the current lifting operation.

2. The vehicle control method according to claim 1, characterized in that, Monitoring the hydraulic pump pressure and determining the calculation start time based on the change in the hydraulic pump pressure includes: Monitor the hydraulic pump pressure. When the hydraulic pump pressure is greater than the first set pressure, obtain a second variable, which is the change in hydraulic pump pressure over time. The calculation start time is obtained based on the second variable, which is the moment when the second variable first becomes less than a first preset value.

3. The vehicle control method according to claim 2, characterized in that, Determining whether to calculate the speed limit includes: Determine whether the engine speed is greater than or equal to the second preset speed and whether the duration exceeds the first preset time; Determine whether the engine output torque is greater than or equal to a set torque, and whether the duration exceeds a second preset time; Determine whether the hydraulic pump pressure is greater than or equal to the second set pressure, and whether the duration exceeds the second preset time; The second set pressure is less than the first set pressure.

4. The vehicle control method according to claim 3, characterized in that, The control method also includes: Determine whether the current lifting operation of the lifting equipment has ended; The determination of whether the current lifting action of the lifting equipment has ended includes: If the hydraulic pump pressure rises from the second set pressure to the first set pressure and then drops back to the second set pressure, it is determined that the current lifting operation of the lifting equipment has ended.

5. The vehicle control method according to claim 1, characterized in that, The control method also includes: During the calculation of the limit speed, a third variable is obtained, which is the change in hydraulic pump pressure every third preset time interval; If the third variable is greater than or equal to the second set value, and the hydraulic pump pressure is always greater than the first set pressure, then the calculation of the limit speed is terminated. Then, the maximum speed of the engine is reset to the original maximum speed, which is the maximum speed set when the vehicle leaves the factory.

6. The vehicle control method according to claim 1, characterized in that, The control method also includes: After calculating the limit speed, during the current lifting operation of the lifting equipment, a fourth variable is obtained, which is the change in hydraulic pump pressure every fourth preset time interval; If the fourth variable is greater than or equal to the third set value, and the hydraulic pump pressure is always greater than the first set pressure, then the calculation of the limit speed is terminated. Then, the maximum speed of the engine is reset to the original maximum speed, which is the maximum speed set when the vehicle leaves the factory.

7. A control system, characterized in that, For controlling the lifting equipment of a vehicle, which is connected to the engine via a hydraulic pump, the control system includes: The first judgment module is used to determine whether the lifting equipment is in a hoisting condition. The second judgment module is used to determine whether to calculate the limit speed. The monitoring module is used to monitor the pressure of the hydraulic pump; During the calculation of the limit speed, the first control unit controls the engine speed to rise to a first set speed and obtains a first variable, which is the change in hydraulic pump pressure per unit number of engine revolutions. The first control unit is also used to call the set variable of the hydraulic pump pressure corresponding to the current lifting action of the lifting equipment, and compare the first variable with the set variable to obtain the limit speed, wherein the limit speed is the speed of the engine when the first variable is equal to the set variable for the first time; After calculating the limit speed, the adjustment unit sets the limit speed to the maximum speed of the engine when performing the current hoisting operation.

8. The control system according to claim 7, characterized in that, The control system also includes a third judgment module, which is used to determine whether the current hoisting action of the lifting equipment has ended; If the hydraulic pump pressure rises from the second set pressure to the first set pressure and then drops back to the second set pressure, the third judgment module determines that the current hoisting action of the lifting equipment has ended.

9. The control system according to claim 7, characterized in that, The control system also includes a second control unit. During the calculation of the limit speed, the second control unit is used to obtain a third variable, which is the change in the hydraulic pump pressure at a third preset time interval. If the monitoring module detects that the third variable is greater than or equal to the second set value, and the hydraulic pump pressure is always greater than the first set pressure, then the second control unit terminates the calculation of the limit speed. Subsequently, the adjustment unit is also used to reset the maximum speed of the engine to the original maximum speed, which is the maximum speed set when the vehicle leaves the factory.

10. The control system according to claim 7, characterized in that, The control system also includes a third control unit. After calculating the limit speed, during the current hoisting operation of the lifting equipment, the third control unit is used to acquire a fourth variable, which is the change in hydraulic pump pressure every fourth preset time interval. If the monitoring module detects that the fourth variable is greater than or equal to the third set value, and the hydraulic pump pressure is always greater than the first set pressure, the third control unit is also used to terminate the calculation of the limit speed. Subsequently, the adjustment unit is also used to reset the maximum speed of the engine to the original maximum speed, which is the maximum speed set when the vehicle leaves the factory.

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