Control method for a hydraulic system, hydraulic system, storage medium and controller

Abstract

The embodiment of the application provides a control method for a hydraulic system, a hydraulic system, a storage medium and a controller. A control port of the hydraulic system is connected with a feedback oil port and a first end of an electric proportional pressure reducing valve, a main oil port is connected with a second end of the electric proportional pressure reducing valve and a receiving oil port, and the method comprises the following steps: acquiring an oil temperature in a hydraulic oil tank in real time; in the case that a working mode of the hydraulic system is switched to a low-temperature mode, determining a first output pressure of a variable pump output to a load end according to a first pressure value of the main oil port and a second pressure value of the control port, so as to determine a flow of the variable pump output to the load end; in the case that the flow does not meet preset working condition requirements in the low-temperature mode, controlling the control port to be disconnected with the feedback oil port, so that the main oil port is connected with the control port through the electric proportional pressure reducing valve; and adjusting a load pressure of the control port to be greater than the second pressure value through the electric proportional pressure reducing valve, so that the flow of the variable pump output to the load end meets the preset working condition requirements.

Description

Technical Field

[0001] This application relates to the field of hydraulic systems, specifically to a control method for hydraulic systems, hydraulic systems, fire trucks, storage media, and controllers. Background Technology

[0002] Load-sensitive hydraulic systems are widely used in the hydraulic systems of construction machinery and vehicles. In a load-sensitive hydraulic system, when the system is under load, the variable pump operates at the pressure required by the load, thus achieving significant energy savings and preventing excess energy from causing the oil to overheat. However, when the system operates at very low ambient temperatures, the low temperature causes the oil viscosity to increase rapidly, resulting in excessive pressure loss in the feedback line. Consequently, the output flow of the variable pump will be less than the flow required by the load, and the output flow will not meet the requirements for low-temperature operating conditions. Summary of the Invention

[0003] The purpose of this application is to provide a control method for a hydraulic system, a hydraulic system, a fire truck, a storage medium, and a controller.

[0004] To achieve the above objectives, the first aspect of this application provides a control method for a hydraulic system. The hydraulic system includes a variable pump equipped with a control port and a main oil port, a load end equipped with a feedback oil port and a receiving oil port, a hydraulic oil tank, and an electro-proportional pressure reducing valve. The control port is connected to the feedback oil port of the load end and the first end of the electro-proportional pressure reducing valve, and the main oil port is connected to the second end of the electro-proportional pressure reducing valve and the receiving oil port of the load end. The control method includes:

[0005] Real-time acquisition of hydraulic oil temperature in the hydraulic oil tank;

[0006] When the hydraulic system's operating mode is switched to low-temperature mode based on the oil temperature, the first pressure value of the main oil port and the second pressure value of the control port are obtained.

[0007] The first output pressure of the variable pump to the load end is determined based on the first pressure value and the second pressure value, and the flow rate of the variable pump to the load end is determined based on the first output pressure.

[0008] Determine whether the flow rate meets the preset operating conditions in low-temperature mode;

[0009] If the flow rate does not meet the preset operating conditions, the control port is disconnected from the feedback oil port at the load end, so that the main oil port is connected to the control port through the electro-proportional pressure reducing valve.

[0010] The load pressure at the control port is adjusted by an electro-proportional pressure reducing valve to make the load pressure greater than the second pressure value, so that the flow rate output by the variable pump to the load end under the action of the load pressure meets the preset operating conditions.

[0011] In one embodiment, adjusting the load pressure at the control port via an electro-proportional pressure reducing valve includes: acquiring characteristic parameters of the electro-proportional pressure reducing valve; determining the opening current of the electro-proportional pressure reducing valve; determining the product of the opening current, characteristic parameters, and a first output pressure as the second output pressure of the electro-proportional pressure reducing valve; and controlling the output pressure of the electro-proportional pressure reducing valve to the second output pressure, so that the load pressure at the control port is adjusted to be greater than the second pressure value via the electro-proportional pressure reducing valve.

[0012] In one embodiment, the hydraulic system further includes an engine connected to a variable displacement pump for powering an electro-proportional pressure reducing valve. Determining the opening current of the electro-proportional pressure reducing valve includes: acquiring the standby pressure of the variable displacement pump; acquiring the real-time speed of the engine; and determining the opening current based on the standby pressure, the real-time speed, and a first pressure value.

[0013] In one embodiment, the opening current is determined according to formula (1):

[0014]

[0015] Where I is the opening current, N is the real-time speed of the engine, P0 is the first pressure value, D is the standby pressure of the variable pump, and K1, K2, and K3 are weighting coefficients.

[0016] In one embodiment, the hydraulic system's operating mode further includes a normal temperature mode, and the control method further includes: when the hydraulic system's operating mode is switched to normal temperature mode according to the oil temperature, the control port is connected to the feedback port at the load end and disconnected from the first end of the electro-proportional pressure reducing valve, and the main oil port is disconnected from the second end of the electro-proportional pressure reducing valve; wherein, in normal temperature mode, the pressure value output by the variable pump to the load end is the pressure value of the main oil port.

[0017] In one embodiment, the hydraulic system further includes a solenoid directional valve. A first end of the solenoid directional valve is connected to the control port of the variable pump, and a second end is connected to the feedback port of the load end and the first end of the electro-proportional pressure reducing valve. If the first output flow of the variable pump does not meet preset operating conditions, the control port is disconnected from the feedback port of the load end, so that the main port is connected to the control port through the electro-proportional pressure reducing valve. This includes: energizing the solenoid directional valve to disconnect the control port of the variable pump from the feedback port of the load end, so that the control port is connected to the first end of the electro-proportional pressure reducing valve through the solenoid directional valve, and the main port is connected to the control port through the electro-proportional pressure reducing valve.

[0018] In one embodiment, the hydraulic system's operating mode further includes a normal temperature mode, and the control method further includes: when the hydraulic system's operating mode is switched to normal temperature mode according to the oil temperature, controlling the solenoid directional valve to de-energize, so that the control port of the variable pump is disconnected from the first end of the electro-proportional pressure reducing valve, and connected to the feedback port of the load end.

[0019] A second aspect of this application provides a controller configured to perform the control method described above for a hydraulic system.

[0020] A third aspect of this application provides a hydraulic system, comprising:

[0021] The variable pump is equipped with a control port and a main oil port. The main oil port is connected to the second end of the electro-proportional pressure reducing valve and the receiving oil port of the load end to supply hydraulic oil to the load end. The control port is connected to the feedback oil port of the load end and the first end of the electro-proportional pressure reducing valve.

[0022] The load end is equipped with a feedback port and a receiving port.

[0023] Hydraulic oil tank, used to store hydraulic oil;

[0024] Electro-proportional pressure reducing valve, used to regulate the load pressure at the control port;

[0025] The controller described above is configured to perform the control method for the hydraulic system described above.

[0026] In one embodiment, the hydraulic system further includes:

[0027] The electromagnetic directional valve has its first end connected to the control port of the variable pump, and its second end connected to the feedback port of the load end and the first end of the electro-proportional pressure reducing valve.

[0028] The engine, connected to the variable pump, powers the electro-proportional pressure reducing valve.

[0029] The fourth aspect of this application provides a fire truck including the aforementioned hydraulic system.

[0030] A fifth aspect of this application provides a machine-readable storage medium storing instructions that, when executed by a processor, configure the processor to perform the aforementioned control method for a hydraulic system.

[0031] The above technical solution enables the hydraulic system to operate normally in low-temperature environments. By controlling the electro-proportional pressure reducing valve to adjust the load pressure of the variable pump, the output pressure and flow rate of the variable pump meet the system's operating requirements in low-temperature environments.

[0032] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0033] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. In the drawings:

[0034] Figure 1 This schematic diagram illustrates an application environment of a control method for a hydraulic system according to an embodiment of this application.

[0035] Figure 2 A schematic diagram illustrating a control method for a hydraulic system according to an embodiment of this application is shown.

[0036] Figure 3 The diagram illustrates the internal structure of a computer device according to an embodiment of this application.

[0037] Figure Labels

[0038] 1. Variable pump 2. Load end

[0039] 3. Electro-proportional pressure reducing valve; 4. Hydraulic oil tank

[0040] 5 First pressure sensor 6 Solenoid directional valve

[0041] 7 Second pressure sensor 8 Engine

[0042] 9 Temperature sensor 10 Reversing valve for boarding / alighting

[0043] A Main Oil Port M Control Port

[0044] C Feedback port D Receive port Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for illustration and explanation of the embodiments of this application and are not intended to limit the embodiments of this application. 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.

[0046] The control method for hydraulic systems provided in this application can be applied to, for example... Figure 1 The application environment shown. Among them, such as... Figure 1 As shown, a hydraulic system is provided, comprising:

[0047] The variable pump 1 is equipped with a control port M and a main oil port A. The main oil port A is connected to the second end of the electro-proportional pressure reducing valve 3 and the receiving oil port D of the load end 2, and is used to supply hydraulic oil to the load end 2. The control port M is connected to the feedback oil port C of the load end 2 and the first end of the electro-proportional pressure reducing valve 3.

[0048] Load end 2 is equipped with feedback port C and receiving port D.

[0049] Hydraulic oil tank 4 is used to store hydraulic oil.

[0050] Electro-proportional pressure reducing valve 3 is used to regulate the load pressure at control port M.

[0051] The electromagnetic directional valve 6 has its first end connected to the control port M of the variable pump 1, and its second end connected to the feedback port C of the load end 2 and the first end of the electro-proportional pressure reducing valve 3.

[0052] Engine 8, connected to variable pump 1, is used to power electro-proportional pressure reducing valve 3.

[0053] The first pressure sensor 5 is installed on the variable pump 1 and is used to detect the pressure at the main oil port in real time.

[0054] The second pressure sensor 7 is installed at the first end of the electro-proportional pressure reducing valve 3 and is used to detect the output pressure of the electro-proportional pressure reducing valve 3.

[0055] Temperature sensor 9 is installed on hydraulic oil tank 4 to detect the temperature of hydraulic oil in hydraulic oil tank 4 in real time.

[0056] The on / off reversing valve 10 is connected to the load end 2 and is used to switch between different sub-load ends.

[0057] The controller (not shown in the figure) is electrically connected to each component in the hydraulic system. It can control the output pressure of the variable pump 1 and adjust the output flow of the variable pump 1 according to the ambient temperature of the hydraulic system and the corresponding working conditions to meet the working conditions at the current temperature.

[0058] Figure 2 A schematic flowchart of a control method for a hydraulic system according to an embodiment of this application is shown. Figure 2 As shown in one embodiment of this application, a control method for a hydraulic system is provided, comprising the following steps:

[0059] Step 201: Obtain the real-time temperature of the hydraulic oil in the hydraulic oil tank.

[0060] Step 202: When the hydraulic system's operating mode is switched to low-temperature mode based on the oil temperature, the first pressure value of the main oil port and the second pressure value of the control port are obtained.

[0061] Step 203: Determine the first output pressure of the variable pump to the load end based on the first pressure value and the second pressure value, and determine the flow rate of the variable pump to the load end based on the first output pressure.

[0062] Step 204: Determine whether the flow rate meets the preset operating conditions in low temperature mode.

[0063] Step 205: If the flow rate does not meet the preset operating conditions, the control port is disconnected from the feedback oil port at the load end, so that the main oil port is connected to the control port through the electro-proportional pressure reducing valve.

[0064] Step 206: Adjust the load pressure at the control port through the electro-proportional pressure reducing valve so that the load pressure is greater than the second pressure value, so that the flow rate output by the variable pump to the load end under the action of the load pressure meets the preset operating condition requirements.

[0065] The function of a hydraulic system is to increase force by changing pressure. Typically, a complete hydraulic system consists of five parts: power element, actuator, control element, auxiliary elements (accessories), and hydraulic oil. Hydraulic systems can be divided into two categories: hydraulic transmission systems and hydraulic control systems. Hydraulic transmission systems primarily transmit power and motion, while hydraulic control systems ensure the hydraulic system output meets specific performance requirements (especially dynamic performance). A hydraulic system consists of signal control and hydraulic power components. The signal control component drives the control valves in the hydraulic power component. A variable displacement pump is a pump with a variable displacement. Variable displacement pumps can be single-acting vane pumps, radial piston pumps, or axial piston pumps, and are widely used in hydraulic transmission fields such as metallurgy, mining, construction machinery, shipbuilding, and civil aviation ground equipment. In this technical solution, the variable displacement pump can be used to deliver hydraulic oil from the hydraulic tank to the load end of the operating condition through transmission pressure. The variable displacement pump is equipped with a control port and a main port. The main port is used to deliver the flow rate to the receiving port at the load end through the transmission pressure of the variable displacement pump. After receiving the flow rate from the variable pump, the load end sends a feedback pressure to the control port connected to the feedback port via the feedback port. Upon receiving the feedback pressure, the variable pump can adjust the output pressure of the main port accordingly, thereby adjusting the pump's flow rate to meet the current operating requirements.

[0066] Furthermore, the controller acquires the hydraulic oil temperature in the hydraulic tank in real time and switches the hydraulic system's operating mode to low-temperature mode based on the oil temperature. The correspondence between temperature and low-temperature mode—specifically, the temperature range within which the system is considered to be in low-temperature mode—can be set according to actual needs. The controller acquires the first pressure value at the main port of the variable pump, the second pressure value at the control port, and the load condition at the load end in low-temperature mode, and calculates the theoretical load pressure required by the load end based on the load condition. The control port is connected to the feedback port at the load end through the system pipeline. When the load end operates under the output pressure of the variable pump, it feeds back a pressure value to the control port through the feedback port. This pressure is fed back to the control port after pipeline losses, and the second pressure value at the control port is the feedback pressure after pipeline losses. Based on the operating characteristics of the variable pump, it has an initial pressure to offset the pressure loss caused by the variable pump's output pressure through the pipeline. The controller combines the variable pump's output pressure, the second pressure value at the control port, and the first pressure value at the main port for comprehensive analysis to calculate the theoretical output pressure of the variable pump in the current low-temperature mode, i.e., the first output pressure. After the controller calculates the theoretical output pressure of the variable pump, it can then calculate the theoretical flow rate that the variable pump delivers to the load end under the action of the theoretical output pressure.

[0067] Furthermore, it is determined whether the theoretical flow rate delivered by the variable pump to the load side at this time meets the flow rate required for normal operation of the load side in low-temperature mode. If the flow rate delivered by the variable pump to the load side cannot meet the actual needs of the load side, it can be determined that the output pressure of the variable pump is too low, resulting in an insufficient flow rate under the low output pressure. The controller then disconnects the control port of the variable pump from the feedback port of the load side and connects it to one end of the electro-proportional pressure reducing valve, so that the control port and the main port of the variable pump are respectively connected to the two ends of the electro-proportional pressure reducing valve. After the electro-proportional pressure reducing valve connects the two ports of the variable pump, the controller can control the electro-proportional pressure reducing valve to calculate the actual output pressure that the electro-proportional pressure reducing valve needs to deliver to the control port based on the output pressure of the main port, i.e., the first pressure value. Here, the electro-proportional pressure reducing valve is an electrically controlled valve that controls the output pressure through current.

[0068] Furthermore, after the electro-proportional pressure reducing valve calculates the pressure to be output to the control port based on the first pressure value, the controller uses the output pressure of the electro-proportional pressure reducing valve as the load pressure required by the current control port and outputs it to the control port, so that the output flow of the variable pump under the load pressure meets the preset operating condition requirements at the current temperature, that is, the flow required for normal operation of the load end.

[0069] The above technical solution enables the hydraulic system to operate normally in low-temperature environments. By controlling the electro-proportional pressure reducing valve to adjust the load pressure at the variable pump control port according to the actual flow demand at the load end, the output pressure of the variable pump is changed, so that the output flow delivered by the variable pump to the load end under the load pressure meets the system's operating requirements in low-temperature environments.

[0070] Figure 2 This is a flowchart illustrating a control method for a hydraulic system in one embodiment. It should be understood that, although... Figure 2 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 2 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0071] In one embodiment, if the flow rate delivered by variable pump 1 to load 2 is insufficient to meet the actual needs of load 2, it is determined that the output pressure of variable pump 1 is too low, resulting in a low flow rate under such low output pressure. The controller then disconnects the control port M of variable pump 1 from the feedback port C of load 2 and connects it to one end of electro-proportional pressure reducing valve 3, thus connecting the control port M of variable pump 1 and the main port A to the two ends of electro-proportional pressure reducing valve 3 respectively. After the electro-proportional pressure reducing valve 3 connects to both ports of variable pump 1, the controller can control the electro-proportional pressure reducing valve 3 to calculate the actual output required to the control port M based on the output pressure of the main port A, i.e., the first pressure value. Specifically, the characteristic parameters of the electro-proportional pressure reducing valve 3 are obtained, and the current opening current of the electro-proportional pressure reducing valve 3 is calculated. The characteristic parameters are fixed values, determined according to the model of the electro-proportional pressure reducing valve 3 purchased according to actual needs. After obtaining the characteristic parameters and the opening current, the controller can calculate the current output pressure of the electro-proportional pressure reducing valve 3 based on the product of the characteristic parameters, the opening current, and the first output pressure of variable pump 1.

[0072] In one embodiment, the hydraulic system further includes an engine 8 connected to a variable pump 1, which provides power to the electro-proportional pressure reducing valve 3 and provides real-time feedback of the opening current to the electro-proportional pressure reducing valve 3. This ensures that the output pressure of the electro-proportional pressure reducing valve 3 always matches the speed of the engine 8, preventing engine stalling due to mismatch between the power and torque of the engine 8 and the demand when the load end 2 suddenly increases. Specifically, the opening current of the electro-proportional pressure reducing valve 3 is related to the speed of the engine 8. The controller obtains the real-time speed of the engine 8 and the standby pressure of the variable pump 1. Based on the real-time speed, standby pressure, and the first pressure value at the oil outlet, the opening current fed back by the engine 8 to the electro-proportional pressure reducing valve 3 can be calculated. The standby pressure refers to an initial pressure set by the variable pump 1 at idle speed. This initial pressure is a fixed value and is generally small, used to offset the pressure loss caused when the pressure is transmitted through the system pipeline. Specifically, the opening current can be determined according to formula (1):

[0073]

[0074] Where I is the opening current, N is the real-time speed of engine 8, P0 is the first pressure value, D is the standby pressure of variable pump 1, and K1, K2, and K3 are weighting coefficients.

[0075] Furthermore, after the electro-proportional pressure reducing valve 3 determines the output pressure based on the opening current fed back by the engine 8, the controller uses the output pressure of the electro-proportional pressure reducing valve 3 as the load pressure required by the current control port M and outputs it to the control port M, so that the output flow of the variable pump 1 under the action of the load pressure meets the preset operating condition requirements at the current temperature, that is, the flow required for the normal operation of the load end 2.

[0076] In one embodiment, the hydraulic system also includes a normal temperature mode. The controller acquires the oil temperature of the hydraulic oil in the hydraulic oil tank 4 in real time, and switches the hydraulic system to normal temperature mode based on the oil temperature. In normal temperature mode, the controller connects control port M to the feedback port C of the load end 2 and disconnects it from the first end of the electro-proportional pressure reducing valve 3, and disconnects main port A from the second end of the electro-proportional pressure reducing valve 3. This means the main port A of the variable pump 1 and control port M are connected to the two ports of the load end 2 respectively. At this time, the pressure output from the variable pump 1 to the load end 2 is the pressure value of main port A. In this technical solution, normal temperature mode can refer to a situation where the load end 2 of the hydraulic system has low demand or the hydraulic oil temperature is within the normal operating temperature range. Normal temperature mode can also be called load-sensitive mode. A system in load-sensitive mode is a hydraulic circuit that senses the system's pressure and flow demand and only provides the required flow and pressure. The system in load-sensitive mode has lower power loss and higher efficiency than conventional hydraulic systems, exhibiting high efficiency and low power loss.

[0077] In one embodiment, the hydraulic system further includes an electromagnetic directional valve 6, which uses the force generated when an electromagnet is energized to move the spool valve core. Specifically, the first end of the electromagnetic directional valve 6 is connected to the control port M of the variable pump 1, and the second end is connected to the feedback port C of the load end 2 and the first end of the electro-proportional pressure reducing valve 3. When the first output flow of the variable pump 1 does not meet the preset operating condition requirements, controlling the control port M to disconnect from the feedback port C of the load end 2, so that the main port A is connected to the control port M through the electro-proportional pressure reducing valve 3, includes: when the first output flow of the variable pump 1 does not meet the preset operating condition requirements, energizing the electromagnetic directional valve 6, causing the control port M of the variable pump 1 to disconnect from the feedback port C of the load end 2, so that the control port M is connected to the first end of the electro-proportional pressure reducing valve 3 through the electromagnetic directional valve 6, and the main port A is connected to the control port M through the electro-proportional pressure reducing valve 3, thereby connecting the control port M and the main port A of the variable pump 1 to the two ends of the electro-proportional pressure reducing valve 3 respectively. After the electro-proportional pressure reducing valve 3 connects to the two ports of the variable pump 1, the controller can calculate the current output pressure of the electro-proportional pressure reducing valve 3 based on the product of the characteristic parameters, the opening current, and the first output pressure of the variable pump 1. After the electro-proportional pressure reducing valve 3 calculates the pressure to be output to the control port M based on the first pressure value, the controller uses the output pressure of the electro-proportional pressure reducing valve 3 as the load pressure required for the current control port M and outputs it to the control port M, so that the output flow rate of the variable pump 1 under the load pressure meets the preset operating condition requirements at the current temperature, that is, the flow rate required for the normal operation of the load end 2.

[0078] Furthermore, when the hydraulic system's operating mode is switched to ambient temperature mode based on the oil temperature, the controller de-energizes the solenoid directional valve 6, disconnecting the control port M of the variable pump 1 from the first end of the electro-proportional pressure reducing valve 3 and connecting it to the feedback port C of the load end 2. That is, the main port A and control port M of the variable pump 1 are respectively connected to the two ports of the load end 2. At this time, the pressure value output by the variable pump 1 to the load end 2 is the pressure value of the main port A.

[0079] In one embodiment, a fire truck, also known as a fire engine, is provided. A fire truck is a vehicle designed and manufactured to be suitable for firefighters, equipped with various firefighting equipment or extinguishing agents, and used by fire brigades for firefighting, assisting in firefighting, or fire rescue. Fire departments in most countries, including China, also use them for other emergency rescue purposes. Fire trucks can transport firefighters to disaster scenes and provide them with various tools for carrying out disaster relief missions. The hydraulic system is an important component of a fire truck.

[0080] The above technical solution enables the hydraulic system to operate normally in low-temperature environments. By controlling the electro-proportional pressure reducing valve to adjust the load pressure at the variable pump control port according to the actual flow demand at the load end, the output pressure of the variable pump is changed, so that the output flow delivered by the variable pump to the load end under the load pressure meets the system's operating requirements in low-temperature environments.

[0081] Compared to existing load-sensitive systems, this technical solution can switch to a low-temperature start-up control mode under set operating conditions. This allows the fire truck's boom to operate at a higher flow rate under low-temperature conditions, unaffected by hydraulic fluid temperature, while maintaining the fire truck's operational efficiency in low-temperature environments. In the low-temperature start-up control mode, the electro-proportional pressure reducing valve's output control pressure is matched to the engine power and torque through an electronic control matching program. This prevents the engine from stalling due to sudden load increases, improving the overall vehicle performance stability. Furthermore, this technical solution allows for free and controllable switching between load-sensitive and low-temperature start-up control modes, combining the energy-saving advantages of load-sensitive systems with the rapid and stable operation of the low-temperature start-up control mode under specific conditions.

[0082] This application provides a storage medium storing a program that, when executed by a processor, implements the aforementioned control method for a hydraulic system. This application also provides a controller for running the program, wherein the program, when running, executes the aforementioned control method for a hydraulic system.

[0083] In one embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 3As shown. The computer device includes a processor A01, a network interface A02, memory (not shown), and a database (not shown) connected via a system bus. The processor A01 provides computing and control capabilities. The memory includes internal memory A03 and a non-volatile storage medium A04. The non-volatile storage medium A04 stores an operating system B01, a computer program B02, and a database (not shown). The internal memory A03 provides an environment for the operation of the operating system B01 and the computer program B02 in the non-volatile storage medium A04. The database stores control data for the hydraulic system. The network interface A02 communicates with external terminals via a network connection. When the computer program B02 is executed by the processor A01, it implements a control method for the hydraulic system.

[0084] Those skilled in the art will understand that Figure 3 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0085] This application provides a device including a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it performs the following steps: real-time acquisition of the hydraulic oil temperature in the hydraulic tank; when switching the hydraulic system's operating mode to a low-temperature mode based on the oil temperature, acquiring a first pressure value at the main oil port and a second pressure value at the control port; determining a first output pressure from the variable pump to the load end based on the first and second pressure values, and determining the flow rate from the variable pump to the load end based on the first output pressure; determining whether the flow rate meets the preset operating condition requirements in the low-temperature mode; if the flow rate does not meet the preset operating condition requirements, disconnecting the control port from the feedback oil port at the load end, so that the main oil port is connected to the control port via an electro-proportional pressure reducing valve; adjusting the load pressure at the control port via the electro-proportional pressure reducing valve to make the load pressure greater than the second pressure value, so that the flow rate from the variable pump to the load end meets the preset operating condition requirements under the load pressure.

[0086] In one embodiment, adjusting the load pressure at the control port via an electro-proportional pressure reducing valve includes: acquiring characteristic parameters of the electro-proportional pressure reducing valve; determining the opening current of the electro-proportional pressure reducing valve; determining the product of the opening current, characteristic parameters, and a first output pressure as the second output pressure of the electro-proportional pressure reducing valve; and controlling the output pressure of the electro-proportional pressure reducing valve to the second output pressure, so that the load pressure at the control port is adjusted to be greater than the second pressure value via the electro-proportional pressure reducing valve.

[0087] In one embodiment, the hydraulic system further includes an engine connected to a variable displacement pump for powering an electro-proportional pressure reducing valve. Determining the opening current of the electro-proportional pressure reducing valve includes: acquiring the standby pressure of the variable displacement pump; acquiring the real-time speed of the engine; and determining the opening current based on the standby pressure, the real-time speed, and a first pressure value.

[0088] In one embodiment, the opening current is determined according to formula (1):

[0089]

[0090] Where I is the opening current, N is the real-time speed of the engine, P0 is the first pressure value, D is the standby pressure of the variable pump, and K1, K2, and K3 are weighting coefficients.

[0091] In one embodiment, the hydraulic system's operating mode further includes a normal temperature mode, and the control method further includes: when the hydraulic system's operating mode is switched to normal temperature mode according to the oil temperature, the control port is connected to the feedback port at the load end and disconnected from the first end of the electro-proportional pressure reducing valve, and the main oil port is disconnected from the second end of the electro-proportional pressure reducing valve; wherein, in normal temperature mode, the pressure value output by the variable pump to the load end is the pressure value of the main oil port.

[0092] In one embodiment, the hydraulic system further includes a solenoid directional valve. A first end of the solenoid directional valve is connected to the control port of the variable pump, and a second end is connected to the feedback port of the load end and the first end of the electro-proportional pressure reducing valve. If the first output flow of the variable pump does not meet preset operating conditions, the control port is disconnected from the feedback port of the load end, so that the main port is connected to the control port through the electro-proportional pressure reducing valve. This includes: energizing the solenoid directional valve to disconnect the control port of the variable pump from the feedback port of the load end, so that the control port is connected to the first end of the electro-proportional pressure reducing valve through the solenoid directional valve, and the main port is connected to the control port through the electro-proportional pressure reducing valve.

[0093] In one embodiment, the hydraulic system's operating mode further includes a normal temperature mode, and the control method further includes: when the hydraulic system's operating mode is switched to normal temperature mode according to the oil temperature, controlling the solenoid directional valve to de-energize, so that the control port of the variable pump is disconnected from the first end of the electro-proportional pressure reducing valve, and connected to the feedback port of the load end.

[0094] This application also provides a computer program product, which, when executed on a data processing device, is suitable for executing an initialization program with the following steps: real-time acquisition of the hydraulic oil temperature in the hydraulic oil tank; when switching the hydraulic system's operating mode to a low-temperature mode based on the oil temperature, acquiring a first pressure value at the main oil port and a second pressure value at the control port; determining a first output pressure from the variable pump to the load end based on the first and second pressure values, and determining the flow rate from the variable pump to the load end based on the first output pressure; determining whether the flow rate meets the preset operating condition requirements in the low-temperature mode; if the flow rate does not meet the preset operating condition requirements, disconnecting the control port from the feedback oil port at the load end, so that the main oil port is connected to the control port through an electro-proportional pressure reducing valve; adjusting the load pressure at the control port through the electro-proportional pressure reducing valve so that the load pressure is greater than the second pressure value, so that the flow rate from the variable pump to the load end under the load pressure meets the preset operating condition requirements.

[0095] In one embodiment, adjusting the load pressure at the control port via an electro-proportional pressure reducing valve includes: acquiring characteristic parameters of the electro-proportional pressure reducing valve; determining the opening current of the electro-proportional pressure reducing valve; determining the product of the opening current, characteristic parameters, and a first output pressure as the second output pressure of the electro-proportional pressure reducing valve; and controlling the output pressure of the electro-proportional pressure reducing valve to the second output pressure, so that the load pressure at the control port is adjusted to be greater than the second pressure value via the electro-proportional pressure reducing valve.

[0096] In one embodiment, the hydraulic system further includes an engine connected to a variable displacement pump for powering an electro-proportional pressure reducing valve. Determining the opening current of the electro-proportional pressure reducing valve includes: acquiring the standby pressure of the variable displacement pump; acquiring the real-time speed of the engine; and determining the opening current based on the standby pressure, the real-time speed, and a first pressure value.

[0097] In one embodiment, the opening current is determined according to formula (1):

[0098]

[0099] Where I is the opening current, N is the real-time speed of the engine, P0 is the first pressure value, D is the standby pressure of the variable pump, and K1, K2, and K3 are weighting coefficients.

[0100] In one embodiment, the hydraulic system's operating mode further includes a normal temperature mode, and the control method further includes: when the hydraulic system's operating mode is switched to normal temperature mode according to the oil temperature, the control port is connected to the feedback port at the load end and disconnected from the first end of the electro-proportional pressure reducing valve, and the main oil port is disconnected from the second end of the electro-proportional pressure reducing valve; wherein, in normal temperature mode, the pressure value output by the variable pump to the load end is the pressure value of the main oil port.

[0101] In one embodiment, the hydraulic system further includes a solenoid directional valve. A first end of the solenoid directional valve is connected to the control port of the variable pump, and a second end is connected to the feedback port of the load end and the first end of the electro-proportional pressure reducing valve. If the first output flow of the variable pump does not meet preset operating conditions, the control port is disconnected from the feedback port of the load end, so that the main port is connected to the control port through the electro-proportional pressure reducing valve. This includes: energizing the solenoid directional valve to disconnect the control port of the variable pump from the feedback port of the load end, so that the control port is connected to the first end of the electro-proportional pressure reducing valve through the solenoid directional valve, and the main port is connected to the control port through the electro-proportional pressure reducing valve.

[0102] In one embodiment, the hydraulic system's operating mode further includes a normal temperature mode, and the control method further includes: when the hydraulic system's operating mode is switched to normal temperature mode according to the oil temperature, controlling the solenoid directional valve to de-energize, so that the control port of the variable pump is disconnected from the first end of the electro-proportional pressure reducing valve, and connected to the feedback port of the load end.

[0103] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0104] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0105] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1The function specified in one or more boxes.

[0106] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0107] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0108] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0109] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0110] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0111] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A control method for a hydraulic system, characterized in that, The hydraulic system includes a variable displacement pump with a control port and a main oil port, a load end with a feedback port and a receiving port, a hydraulic oil tank, and an electro-proportional pressure reducing valve. The control port is connected to the feedback port of the load end and the first end of the electro-proportional pressure reducing valve. The main oil port is connected to the second end of the electro-proportional pressure reducing valve and the receiving port of the load end. The control method includes: The temperature of the hydraulic oil in the hydraulic oil tank is acquired in real time. When the hydraulic system is switched to a low-temperature mode based on the oil temperature, the first pressure value of the main oil port and the second pressure value of the control port are obtained. The first output pressure of the variable pump to the load end is determined based on the first pressure value and the second pressure value, and the flow rate of the variable pump to the load end is determined based on the first output pressure. Determine whether the flow rate meets the preset operating condition requirements under the low temperature mode; If the flow rate does not meet the preset operating condition requirements, the control port is disconnected from the feedback oil port at the load end, so that the main oil port is connected to the control port through the electro-proportional pressure reducing valve. The load pressure at the control port is adjusted by the electro-proportional pressure reducing valve so that the load pressure is greater than the second pressure value, so that the flow rate output by the variable pump to the load end under the action of the load pressure meets the preset operating condition requirements. The adjustment of the load pressure at the control port via the electro-proportional pressure reducing valve includes: Obtain the characteristic parameters of the electro-proportional pressure reducing valve; Determine the opening current of the electro-proportional pressure reducing valve; The product of the opening current, the characteristic parameter, and the first output pressure is determined as the second output pressure of the electro-proportional pressure reducing valve. The output pressure of the electro-proportional pressure reducing valve is controlled to be the second output pressure, so that the load pressure of the control port is adjusted to be greater than the second pressure value through the electro-proportional pressure reducing valve.

2. The control method for a hydraulic system according to claim 1, characterized in that, The hydraulic system also includes an engine connected to the variable pump for providing power to the electro-proportional pressure reducing valve. The engine provides real-time feedback of the opening current to the electro-proportional pressure reducing valve, thereby matching the output pressure of the electro-proportional pressure reducing valve with the engine speed. Determining the opening current of the electro-proportional pressure reducing valve includes: Obtain the standby pressure of the variable pump; Obtain the real-time speed of the engine; The opening current is determined based on the standby pressure, the real-time rotation speed, and the first pressure value.

3. The control method for a hydraulic system according to claim 1, characterized in that, The hydraulic system also includes a normal temperature mode as its operating mode, and the control method further includes: When the hydraulic system's operating mode is switched to the ambient temperature mode based on the oil temperature, the control port is connected to the feedback port of the load end and disconnected from the first end of the electro-proportional pressure reducing valve, and the main port is disconnected from the second end of the electro-proportional pressure reducing valve. In the normal temperature mode, the pressure value output by the variable pump to the load end is the pressure value of the main oil port.

4. The control method for a hydraulic system according to claim 1, characterized in that, The hydraulic system further includes a solenoid directional valve, the first end of which is connected to the control port of the variable pump, and the second end of which is connected to the feedback port of the load end and the first end of the electro-proportional pressure reducing valve. The step of controlling the control port to disconnect from the feedback port of the load end when the first output flow of the variable pump does not meet the preset operating condition requirements, so that the main port is connected to the control port through the electro-proportional pressure reducing valve, includes: If the first output flow of the variable pump does not meet the preset operating condition requirements, the solenoid directional valve is energized to disconnect the control port of the variable pump from the feedback port of the load end, so that the control port is connected to the first end of the electro-proportional pressure reducing valve through the solenoid directional valve, and the main port is connected to the control port through the electro-proportional pressure reducing valve.

5. The control method for a hydraulic system according to claim 4, characterized in that, The hydraulic system also includes a normal temperature mode as its operating mode, and the control method further includes: When the hydraulic system's operating mode is switched to the ambient temperature mode based on the oil temperature, the solenoid directional valve is de-energized, causing the control port of the variable pump to disconnect from the first end of the electro-proportional pressure reducing valve and connect to the feedback port of the load end.

6. A controller, characterized in that, It is configured to perform the control method for a hydraulic system according to any one of claims 1 to 5.

7. A hydraulic system, characterized in that, The hydraulic system includes: The variable pump is equipped with a control port and a main oil port. The main oil port is connected to the second end of the electro-proportional pressure reducing valve and the receiving oil port of the load end, and is used to supply hydraulic oil to the load end. The control port is connected to the feedback oil port of the load end and the first end of the electro-proportional pressure reducing valve. The load end is equipped with a feedback port and a receiving port; A hydraulic oil tank is used to store the hydraulic oil; The electro-proportional pressure reducing valve is used to adjust the load pressure at the control port; The controller according to claim 6.

8. The hydraulic system according to claim 7, characterized in that, The hydraulic system also includes: An electromagnetic directional valve, wherein the first end of the electromagnetic directional valve is connected to the control port of the variable pump, and the second end is connected to the feedback port of the load end and the first end of the electro-proportional pressure reducing valve. An engine, connected to the variable pump, is used to provide power to the electro-proportional pressure reducing valve. The engine provides real-time feedback of the opening current to the electro-proportional pressure reducing valve, thereby matching the output pressure of the electro-proportional pressure reducing valve with the engine speed.

9. A fire truck, characterized in that, Includes the hydraulic system according to claim 7 or 8.

10. A machine-readable storage medium storing instructions thereon, characterized in that, When executed by a processor, this instruction causes the processor to be configured to perform a control method for a hydraulic system according to any one of claims 1 to 5.

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