An energy-saving hydraulic control system for heavy-duty reach stackers with multi-pump flow distribution and merging, and its usage method.

Abstract

A multi-pump flow distribution and merging energy-saving hydraulic control system and its usage method for heavy-duty reach stackers are disclosed. The system includes a load-sensitive pump group, a pressure feedback shuttle valve group, a multi-way valve, a telescopic and luffing balance valve group, a spreader oil supply valve group, a steering gear, and a controller. The pressure feedback shuttle valve group has two shuttle valves that collect the LS port pressure of different components and feed it back to the corresponding pump group. The controller is connected to the engine and dynamically adjusts the pump group based on pressure and flow sensor data. The method involves on-demand flow distribution and power merging, adapting to three working conditions: no-load, medium-load, and heavy-load. In no-load conditions, the multi-pump full-displacement merging achieves rapid response; in medium-load conditions, selective pump activation achieves power matching; and in heavy-load conditions, differentiated flow output ensures the stability of core operations. This invention achieves precise control of flow and power, reduces pressure and flow losses, balances operational efficiency and energy saving, and achieves deep power matching between the engine and hydraulic system, significantly reducing the operating fuel consumption of heavy-duty reach stackers.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, specifically to an energy-saving hydraulic control system and its usage method for heavy-duty front cranes with multi-pump flow distribution and merging. Background Technology

[0002] Heavy-duty reach stackers are core equipment for container loading and unloading in ports and logistics parks. They need to operate under high load for extended periods, and their power systems suffer from high fuel consumption and significant energy loss, which contradicts the development concept of green logistics.

[0003] Currently, energy-saving improvements for heavy-duty reach stackers in the industry are mainly divided into two categories: engine fuel consumption control and hydraulic control.

[0004] Engine fuel consumption control and energy saving: Fuel consumption is reduced by optimizing the power system architecture, adaptive load adjustment, and intelligent idle speed management. For example, hydrostatic technology is used to replace the traditional transmission, EDM ecological driving mode is set, and automatic speed reduction is implemented when not in operation. This type of solution mainly focuses on optimizing the engine itself and does not solve the energy loss problem from the core energy supply link of the hydraulic system.

[0005] Hydraulic control energy saving: Although the use of load-sensitive variable pumps and LS control system, potential energy recovery device, high-pressure hydraulic circuit, etc. can reduce hydraulic system losses to a certain extent, the existing solution has a single flow distribution strategy and cannot achieve precise multi-pump coordination and flow merging according to the load requirements of different working conditions of the front crane. The power matching degree of the pump set is low, and the balance between energy saving effect and working efficiency is poor.

[0006] In summary, the existing technology lacks a hydraulic control system that can adapt to all working conditions of heavy-duty reach stackers under no-load, medium-load, and heavy-load conditions, realize intelligent flow distribution and merging of multiple pumps, and deeply match engine power, which urgently needs further improvement. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an energy-saving hydraulic control system and method for heavy-duty front cranes with multi-pump flow distribution and merging. The system and method are based on load-sensitive adaptive control of multi-pump collaboration to realize on-demand flow distribution and power merging regulation, which can accurately adapt to different working conditions, improve working efficiency while significantly reducing system energy consumption, and achieve deep power matching between engine and hydraulic system.

[0008] This invention is achieved through the following technical solution: an energy-saving hydraulic control system for heavy-duty reach stackers with multi-pump flow distribution and merging, comprising a load-sensitive pump group, the output end of which is connected to a multi-way valve, a spreader oil supply valve group, and a steering gear. The multi-way valve is connected to a telescopic cylinder and a luffing cylinder respectively through a telescopic balance valve group and a luffing balance valve group. The LS port of the multi-way valve, the spreader oil supply valve group, and the steering gear is connected to the LS port of the load-sensitive pump group through a pressure feedback shuttle valve group. The system also includes a controller, the input end of which is connected to a pressure sensor and a flow sensor. The pressure sensor and flow sensor collect real-time pressure and flow demand data of each actuator in the system. The output end of the controller communicates with the engine ECU via a CAN bus, and the engine provides power to the load-sensitive pump group.

[0009] The pressure feedback shuttle valve group includes a two-way shuttle valve network consisting of pressure feedback shuttle valve I and pressure feedback shuttle valve II, used to collect the system's highest load pressure and feed it back to the load-sensitive pump group. The load-sensitive pump group includes four load-sensitive pumps with identical structures, namely load-sensitive pump I, load-sensitive pump II, load-sensitive pump III, and load-sensitive pump IV. The input end of pressure feedback shuttle valve I is connected to the LS port of the multi-way valve and the LS port of the spreader oil supply valve group, and the output end is connected to the LS port of load-sensitive pump II. The input end of pressure feedback shuttle valve II is connected to the LS port of the multi-way valve and the LS port of the steering gear, and the output end is connected to the LS ports of load-sensitive pump III and load-sensitive pump IV. The LS port of load-sensitive pump I is directly connected to the LS port of the multi-way valve.

[0010] Furthermore, the load-sensitive pump includes a variable pump, an LS valve, a pressure shut-off valve, and a variable piston.

[0011] The multi-way valve includes a three-position seven-way proportional pilot valve and a two-position three-way proportional valve. The pilot pressure is fed back to the three-position seven-way proportional pilot valve through the two-position three-way proportional valve, and the opening size and direction of its main valve port are controlled by the three-position seven-way proportional pilot valve, thereby controlling the flow rate and direction of hydraulic oil flowing into the telescopic cylinder and the luffing cylinder, so as to realize the adjustment of the cylinder speed and telescopic action.

[0012] Both the telescopic balance valve group and the luffing balance valve group are equipped with directional control valves and cartridge valves. Through the coordinated action of the directional control valves and cartridge valves, the luffing and telescopic functions of the telescopic cylinder and the luffing cylinder are realized, while ensuring the stability of the cylinder action.

[0013] The load-sensitive pump unit is connected to the engine through two power take-off ports of the gearbox. The engine provides power to the load-sensitive pump unit. The controller dynamically adjusts the displacement and load of the load-sensitive pump unit according to the engine's real-time torque and speed parameters to achieve power matching between the engine and the main pump.

[0014] The pressure and flow sensors are installed in the hydraulic circuits of each actuator to collect pressure and flow demand data of the telescopic cylinder, luffing cylinder, spreader oil supply valve group and steering gear in real time, and transmit the data to the controller. The controller has pre-stored pressure thresholds for working condition determination and actuator action priority rules.

[0015] A method for using a multi-pump flow distribution and merging energy-saving hydraulic control system for heavy-duty reach stackers, applicable to any of the above-mentioned multi-pump flow distribution and merging energy-saving hydraulic control systems for heavy-duty reach stackers, wherein the controller, based on real-time data collected by pressure sensors and flow sensors, and in conjunction with engine parameters, performs differentiated control of the load-sensitive pump group to adapt to three working conditions: no-load, medium-load, and heavy-load. Specifically, the method includes the following steps:

[0016] S1. No-load operation control: When the pressure at the LS port of the steering gear and spreader oil supply valve group is close to 0, the pressure feedback shuttle valve I and pressure feedback shuttle valve II, after pressure comparison, trigger the four load-sensitive pumps to run at full displacement to quickly establish system pressure. The hydraulic oil is then delivered to the telescopic cylinder and luffing cylinder after being combined through the multi-way valve to achieve rapid response of luffing and boom extension.

[0017] S2, Medium-load operating condition control: The controller receives pressure and flow data from each actuator. Based on the preset algorithm and engine power matching principle, it selectively activates the partial load sensitive pump through the pressure signal transmission of pressure feedback shuttle valve I and pressure feedback shuttle valve II, and precisely adjusts the pump's output displacement. The non-essential load sensitive pump automatically shuts down, so that the engine operates in the high-efficiency power range.

[0018] S3, Heavy-duty operation control: Four load-sensitive pumps output differentiated flow rates according to the load requirements of each actuator. The controller dynamically optimizes the pump output based on the engine's real-time torque and speed parameters, allocates flow rates according to the actuator's action priority, distributes pumps to different hydraulic circuits during compound actions, and achieves flow merging of pumps during single actions.

[0019] In step S2, the controller, constrained by the engine's high-efficiency zone, calculates the hydraulic power P based on the real-time pressure p and flow rate Q, where P = pQ / 60, ensuring that the total power of the pump set does not exceed the engine's available power. When only light-load main operation needs to be performed, only the load-sensitive pump I needs to be activated to meet the flow requirements. When lifting medium-weight loads, the controller transmits a pressure signal through the pressure feedback shuttle valve I, simultaneously activating load-sensitive pumps I and II to achieve flow superposition. When a combined steering and main operation action needs to be performed, the controller compares the pressure signal through the pressure feedback shuttle valve II and selectively activates load-sensitive pumps III and / or IV to supplement the flow to the steering gear.

[0020] In step S3, the action priority of the actuator is sorted in the order of hoisting, luffing, telescoping, steering, and spreader operation. Actions with higher priority get hydraulic flow first, while actions with lower priority adjust their operating speed adaptively according to the remaining flow to ensure the stability of core actions under heavy load.

[0021] The division of no-load, medium-load, and heavy-load operating conditions is based on the comparison between the real-time load pressure of the system and the preset pressure threshold. The controller automatically judges the operating condition and switches the control strategy according to the data collected by the pressure sensor, so as to realize the adaptive switching of operating conditions.

[0022] The present invention has the following advantages:

[0023] 1. This invention uses four load-sensitive pumps in conjunction with two pressure feedback shuttle valve groups to form the core power control unit, which realizes the on-demand distribution of flow and power merging. The action with higher load takes priority to obtain the main flow, and the other actions are adaptively adjusted according to the remaining flow, which greatly reduces flow and pressure loss and has a significant energy-saving effect.

[0024] 2. The controller communicates with the engine ECU in real time via the CAN bus, and can dynamically adjust the pump displacement and load according to the engine's real-time torque and speed parameters to achieve deep power matching between the engine and the main pump, so that the engine always operates in the high-efficiency power range and further reduce fuel consumption.

[0025] 3. The system can accurately adapt to three working conditions: no-load, medium-load, and heavy-load. When no-load, multiple pumps with full displacement are combined to achieve rapid response of the actuator. When medium-load, selective pump start-up reduces energy consumption. When heavy-load, differentiated flow output ensures the stability of core actions, taking into account both work efficiency and energy saving effect.

[0026] 4. The LS valve is used to achieve constant difference control between pump output pressure and load pressure. Combined with the maximum load pressure acquisition and feedback of the shuttle valve group, the system pressure loss is minimized. At the same time, the proportional pilot control of the multi-way valve enables precise adjustment of the actuator action, improving the operating accuracy of the equipment. Attached Figure Description

[0027] The accompanying drawings, as part of this invention, are provided to further illustrate the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation thereof. Clearly, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0028] In the attached diagram:

[0029] Figure 1 This is a schematic diagram of the hydraulic control system of the present invention;

[0030] Figure 2 This is a schematic diagram of the telescopic and amplitude-changing valve group of the hydraulic control system of the present invention;

[0031] Figure 3 This is a schematic diagram of the multi-way valve, steering gear, and spreader oil supply valve group of the hydraulic control system of the present invention;

[0032] Figure 4 This is a schematic diagram of the load-sensitive pump group of the hydraulic control system of the present invention.

[0033] In the diagram: 1.1 Load-sensitive pump I, 1.2 Load-sensitive pump II, 1.3 Load-sensitive pump III, 1.4 Load-sensitive pump IV, 2.1 Pressure feedback shuttle valve I, 2.2 Pressure feedback shuttle valve II, 3 Multi-way valve, 4 Telescopic balance valve assembly, 5 Luffing balance valve assembly, 6 Telescopic cylinder, 7 Luffing cylinder, 8 Variable pump, 9 LS valve, 10 Pressure shut-off valve, 11 Variable piston, 12 Three-position seven-way proportional pilot valve, 13 Two-position three-way proportional valve, 14 Spreader oil supply valve assembly, 15 Steering gear.

[0034] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0036] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limiting this invention.

[0037] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0038] like Figures 1 to 4The diagram illustrates an energy-saving hydraulic control system for heavy-duty reach stackers, featuring multi-pump flow distribution and merging. It includes a load-sensitive pump group, the output of which is connected to a multi-way valve 3, a spreader supply valve group 14, and a steering gear 15. The multi-way valve 3 is connected to a telescopic cylinder 6 and a luffing cylinder 7 via a telescopic balance valve group 4 and a luffing balance valve group 5, respectively. The LS ports of the multi-way valve 3, spreader supply valve group 14, and steering gear 15 are connected to the LS port of the load-sensitive pump group via a pressure feedback shuttle valve group. The system also includes a controller, the input of which is connected to a pressure sensor and a flow sensor. These sensors collect real-time pressure and flow demand data from each actuator in the system. The controller's output communicates with the engine ECU via a CAN bus, and the engine provides power to the load-sensitive pump group. The load-sensitive pump assembly of this invention is connected to a pressure feedback shuttle valve assembly via a hydraulic circuit. The pressure feedback shuttle valve assembly is hydraulically connected to the LS pressure feedback port of a multi-way valve. The main oil circuit of the multi-way valve is connected to a telescopic balance valve assembly and a luffing balance valve assembly, respectively. The telescopic balance valve assembly is connected to the telescopic cylinder, and the luffing balance valve assembly is connected to the luffing cylinder. The spreader oil supply valve assembly and the LS port of the steering gear are both hydraulically connected to the pressure feedback shuttle valve assembly to provide them with pressure signals. The controller is connected to the load-sensitive pump assembly, pressure sensor, flow sensor, and engine ECU via wiring harnesses, and realizes real-time communication between the engine ECU and the hydraulic control system via a CAN bus.

[0039] like Figures 1 to 4The diagram illustrates an energy-saving hydraulic control system for heavy-duty reach stackers, featuring multi-pump flow distribution and merging. The pressure feedback shuttle valve group comprises a two-way shuttle valve network consisting of pressure feedback shuttle valve I2.1 and pressure feedback shuttle valve II2.2, used to collect the system's highest load pressure and feed it back to the load-sensitive pump group. The load-sensitive pump group includes four identical load-sensitive pumps: load-sensitive pump I1.1, load-sensitive pump II1.2, load-sensitive pump III1.3, and load-sensitive pump IV1.4. The input end of pressure feedback shuttle valve I2.1 is connected to the LS port of multi-way valve 3 and the LS port of the spreader supply valve group 14, while its output end is connected to the LS port of load-sensitive pump II1.2. The input end of pressure feedback shuttle valve II2.2 is connected to the LS port of multi-way valve 3 and the LS port of the diverter 15, while its output end is connected to the LS ports of load-sensitive pumps III1.3 and IV1.4. The LS port of load-sensitive pump I1.1 is directly connected to the LS port of multi-way valve 3. The pressure feedback shuttle valve group of this invention consists of two independent and cooperative shuttle valve networks, namely pressure feedback shuttle valve I and pressure feedback shuttle valve II. One end connects to the LS pressure feedback port of each core component of the system to collect load signals, and the other end connects to the LS port of the load-sensitive pump group to transmit control signals. Specifically, the input end of pressure feedback shuttle valve I is hydraulically connected to the LS port of the multi-way valve and the LS port of the spreader oil supply valve group to collect load pressure signals for luffing, telescopic, hoisting, and spreader operations; the output end is hydraulically connected to the LS port of load-sensitive pump II to transmit the filtered pressure signal unidirectionally to the pump; the input end of pressure feedback shuttle valve II is hydraulically connected to the LS port of the multi-way valve and the LS port of the steering gear to collect load pressure signals for luffing, telescopic, hoisting, and steering operations; the output end is hydraulically connected to the LS ports of load-sensitive pump III and load-sensitive pump IV to transmit the filtered pressure signals synchronously to the two pumps; the LS port of load-sensitive pump I is directly hydraulically connected to the LS port of the multi-way valve as a direct link for the main operating pressure signal, complementing the branch feedback of the shuttle valve group and jointly forming the pressure control signal network of the pump group.

[0040] like Figures 1 to 4 This invention discloses an energy-saving hydraulic control system for heavy-duty reach stackers, featuring multi-pump flow distribution and merging. The load-sensitive pump includes a variable displacement pump 8, an LS valve 9, a pressure shut-off valve 10, and a variable displacement piston 11. The components of the load-sensitive pump work together to achieve pump displacement regulation and pressure control. The pressure regulation of the LS valve satisfies the formula: ΔP 1s =P p -P a =F 1s In the formula, ΔP 1s The constant pressure difference; P p P is the pump outlet pressure; a For load pressure; F 1sThe LS valve spring force ensures that the output pressure of the load-sensitive pump is only a constant pressure difference higher than the load pressure, minimizing system pressure loss; the pressure shut-off valve is used to prevent system overpressure and avoid damage to the hydraulic system due to overload; the variable piston is used to adjust the swashplate angle of the variable pump to change the displacement.

[0041] like Figures 1 to 4 This invention discloses an energy-saving hydraulic control system for heavy-duty reach stackers, featuring multi-pump flow distribution and merging. The multi-way valve 3 includes a three-position seven-way proportional pilot valve 12 and a two-position three-way proportional valve 13. Pilot pressure is fed back to the three-position seven-way proportional pilot valve 12 via the two-position three-way proportional valve 13. The three-position seven-way proportional pilot valve 12 controls the opening size and direction of its main valve port, thereby controlling the flow rate and direction of hydraulic oil flowing into the telescopic cylinder 6 and the luffing cylinder 7, thus regulating the cylinder speed and telescopic movement. This multi-way valve is the core control element of the hydraulic system, integrating an LS pressure feedback port, a three-position seven-way proportional pilot valve, and a two-position three-way proportional valve. It plays a crucial role in regulating hydraulic oil flow / direction, providing load pressure signal feedback, and coordinating with other valve groups / pump groups to adapt to different operating conditions. The pilot pressure is fed back to the three-position seven-way proportional pilot valve via the two-position three-way proportional valve. The three-position seven-way proportional pilot valve controls the opening size and direction of its main valve port based on the magnitude and direction of the pilot pressure. The main valve port flow rate is calculated using the following formula: ,in, For valve outlet flow rate, The valve orifice flow coefficient, The flow area of ​​the orifice is denoted by . The pressure difference across the valve port. The formula for calculating and regulating flow rate is used to determine the oil density. When the three-position seven-way proportional pilot valve is in its upper or lower working position, in addition to fulfilling the actuation requirements of the luffing and telescopic cylinders, it simultaneously replicates the real-time system working pressure to the LS pressure feedback port of the multi-way valve. This pressure signal serves as the core load signal and is transmitted to the pressure feedback shuttle valve assembly, providing a basis for the subsequent opening and displacement adjustment of the load-sensitive pump assembly. Simultaneously, the main oil circuit uses a built-in two-position three-way solenoid valve to control the merging / diversion of hydraulic oil according to working conditions. Under no-load conditions, it achieves merging of hydraulic oil from multiple pumps; under medium / heavy load conditions, it diverts the oil to different actuators as needed.

[0042] like Figures 1 to 4This invention discloses an energy-saving hydraulic control system for heavy-duty reach stackers, featuring multi-pump flow distribution and merging. Both the telescopic balance valve group 4 and the luffing balance valve group 5 are equipped with directional control valves and cartridge valves. Through the coordinated action of the directional control valves and cartridge valves, the luffing and telescopic functions of the telescopic and luffing cylinders are achieved, while simultaneously ensuring the stability of cylinder operation. The hydraulic oil output from the multi-way valves of this invention is delivered to the cylinders after passing through the telescopic balance valve group and the luffing balance valve. It works in conjunction with the directional control valves and cartridge valves within the valve group, utilizing the pressure regulation characteristics of the cartridge valves to ensure the stability of cylinder operation and prevent problems such as cylinder slippage and stalling under load, thus adapting to the heavy-duty operation requirements of heavy-duty reach stackers.

[0043] like Figures 1 to 4 This invention discloses an energy-saving hydraulic control system for heavy-duty reach stackers, featuring multi-pump flow distribution and merging. The load-sensitive pump group is connected to the engine via two power take-off ports on the gearbox. The engine provides power to the load-sensitive pump group. The controller dynamically adjusts the displacement and load of the load-sensitive pump group based on the engine's real-time torque and speed parameters, achieving power matching between the engine and the main pump. In this invention, the engine serves as the sole power source for the pump group consisting of four load-sensitive pumps. It is mechanically connected to the pump group via the two power take-off ports on the gearbox to supply power. Simultaneously, the engine ECU and the hydraulic system controller communicate in real-time via a CAN bus, transmitting real-time engine torque, speed, and other parameters to the controller. The controller, considering the system load's pressure and flow requirements, dynamically adjusts the number of pumps activated, their displacement, and differentiated flow output, achieving deep power matching between the engine and the main pump. This ensures that the total power consumption of the pump group matches the engine's available power, keeping the engine operating within its high-efficiency power range. Furthermore, changes in the hydraulic system load are transmitted back to the engine load through the pump group, forming a closed-loop linkage relationship where the engine supplies power, the pump group delivers power on demand, and dynamic adaptation occurs bidirectionally.

[0044] The working principles of the controller, sensors, pressure feedback shuttle valve assembly, and engine ECU are as follows:

[0045] The controller compares the real-time load pressure collected by the sensor with the preset pressure threshold in the controller to automatically determine whether the current operation is no-load, medium-load or heavy-load. If the hydraulic load changes suddenly (such as a sudden increase from medium load to heavy load), the pressure and flow sensors will collect the changed parameters in real time and transmit them to the controller. The controller will immediately re-analyze the engine parameters and the new load parameters and adjust the number of pumps to be opened and the displacement.

[0046] The controller calculates the available power of the engine based on the engine's real-time torque and speed. Combined with the flow and pressure requirements of the hydraulic system, it calculates the total displacement and number of pumps required by the load-sensitive pump group to ensure that the power consumption of the pump group matches the available power of the engine. At the same time, the pressure feedback shuttle valve group feeds back the highest load pressure of each actuator to the controller and the pump group LS valve in real time. The controller combines this pressure signal to fine-tune the output pressure of the pump to ensure that the pump outlet pressure is only a constant difference higher than the load pressure, thereby reducing pressure loss and further optimizing the engine power consumption.

[0047] For compound actions, the flow ratio of each actuator is allocated according to the priority rules to determine the differentiated output strategy of the pump group. At the same time, when the engine torque or speed fluctuates due to load changes, the ECU will transmit parameters to the controller in real time. If the available power of the engine is insufficient, the controller will reduce the flow supply to non-core actuators, prioritize the core actions, and avoid engine overload and shutdown.

[0048] like Figures 1 to 4 The diagram illustrates an energy-saving hydraulic control system for heavy-duty reach stackers with multi-pump flow distribution and merging. The pressure and flow sensors are installed in the hydraulic circuits of each actuator to collect real-time pressure and flow demand data from the telescopic cylinder, luffing cylinder, spreader oil supply valve group, and steering gear, and transmit the data to the controller. The controller pre-stores pressure thresholds for working condition determination and actuator action priority rules. The pressure and flow sensors of this invention collect real-time pressure and flow demand data from the telescopic cylinder, luffing cylinder, spreader oil supply valve group, and steering gear, and transmit this real-time data to the controller. The controller, as the core control unit of the system, receives various data collected by the sensors and, in conjunction with real-time engine torque, speed, and other parameters, analyzes and judges the data based on a preset algorithm and engine power matching principle. It then dynamically regulates the number of load-sensitive pumps, their displacement, and differentiated flow output. Simultaneously, it automatically judges and switches control strategies for no-load, medium-load, and heavy-load conditions. The sensors provide real-time and accurate load data support for the controller's precise control, while the controller processes the signals collected by the sensors and converts them into specific control commands. The two form a closed-loop linkage relationship of "collection-transmission-processing-control," which is a crucial foundation for achieving multi-condition load-sensitive adaptive control and energy saving in the system.

[0049] A method for using a multi-pump flow distribution and merging energy-saving hydraulic control system for heavy-duty reach stackers, applicable to any of the above-mentioned multi-pump flow distribution and merging energy-saving hydraulic control systems for heavy-duty reach stackers, has the core logic of on-demand distribution and power merging. The actuators with higher loads obtain the main flow, while the speeds of other actuators are adjusted based on the remaining flow. The controller, based on real-time data collected by pressure and flow sensors and combined with engine parameters, performs differentiated control of the load-sensitive pump group to adapt to three working conditions: no-load, medium-load, and heavy-load. Specifically, it includes the following steps:

[0050] S1. No-load operation control: Under no-load conditions, the system has not built up sufficient pressure. The pressure at the LS port of the steering gear 15 and the spreader oil supply valve group 14 is close to 0. After pressure comparison, the pressure feedback shuttle valve I 2.1 and pressure feedback shuttle valve II 2.2 trigger the four load-sensitive pumps to run at full displacement to quickly build up the system pressure to the set pressure of the LS valve. After the hydraulic oil passes through the two-position three-way solenoid valve in the multi-way valve to control the flow path, it is quickly delivered to the telescopic cylinder and the luffing cylinder. At the same time, the steering priority valve ensures that the flow directly reaches the luffing or telescopic cylinder. Other actions such as spreader lateral movement are allocated the remaining flow to achieve rapid response of luffing and boom extension, greatly shorten the equipment preparation time and improve the operation efficiency.

[0051] Specifically, in the electronic control system, when the sensor detects that the pressure at the LS port of the steering gear and spreader oil supply valve group is close to 0, and the engine torque and speed are in the low range with sufficient available power, the controller triggers the four load-sensitive pumps to operate at full displacement, without limiting the engine power. At the same time, in the hydraulic system, pressure feedback shuttle valve I receives the weak pressure from the multi-way valve and the 0 pressure from the spreader oil supply valve group, and after filtering, transmits the weak pressure from the multi-way valve to load-sensitive pump II. Pressure feedback shuttle valve II receives the weak pressure from the multi-way valve and the 0 pressure from the steering gear, and after filtering, transmits the weak pressure from the multi-way valve to load-sensitive pumps III and IV simultaneously. Combining the direct pressure signal from load-sensitive pump I and the multi-way valve, all four load-sensitive pumps receive a consistent base pressure signal, triggering full displacement operation and quickly establishing the system pressure to the LS valve set value, meeting the rapid response requirements of luffing and boom extension.

[0052] S2, Medium-load operating condition control: The system establishes a stable load pressure. The controller receives pressure and flow data from each actuator. Based on the preset algorithm and engine power matching principle, it selectively activates some load-sensitive pumps through the pressure signal transmission of pressure feedback shuttle valve I2.1 and pressure feedback shuttle valve II2.2, and precisely adjusts the pump's output displacement. When the system pressure is stable and the flow demand decreases, the unnecessary load-sensitive pumps automatically stop, allowing the engine to operate in the high-efficiency power range.

[0053] Specifically, the controller uses the engine's high-efficiency range as a constraint. Based on real-time pressure p and flow rate Q, it calculates the hydraulic power P, P = pQ / 60, ensuring that the total power of the pump set does not exceed the engine's available power. In the electronic control system, when the sensor detects that the load pressure is in the medium range, the flow demand changes with the work action, and the LS port pressure of different actuators varies. The controller uses the engine's high-efficiency power range as the core constraint to match the power consumption of the pump set. At the same time, in the hydraulic system, when only light-load main work actions need to be completed, such as luffing and telescopic, with no action on the spreader or steering, the LS port pressure is 0. Both pressure feedback shuttle valve I and pressure feedback shuttle valve II only transmit the main working pressure of the multi-way valve to the corresponding pump set. The controller, based on the pressure magnitude, only activates load-sensitive pump I, or activates load-sensitive pump I simultaneously. The flow rate is superimposed with that of load-sensitive pump II. When lifting medium-weight loads, such as during main operation and spreader operation, pressure is generated at the LS port of the spreader. Pressure feedback shuttle valve I selects the higher pressure from the multi-way valve and the spreader oil supply valve group and transmits it to load-sensitive pump II. The controller opens load-sensitive pump I and load-sensitive pump II according to the total pressure requirement to meet the flow rate requirements of the combined operation. When the main operation and steering operation need to be combined, pressure is generated at the LS port of the steering gear. Pressure feedback shuttle valve II selects the higher pressure from the multi-way valve and the steering gear and transmits it to load-sensitive pump III and load-sensitive pump IV. The controller selectively opens one or two pumps according to the steering pressure to supplement the flow rate of the steering system. At the same time, the combination of load-sensitive pump I and load-sensitive pump II is used to ensure the main operation requirements.

[0054] S3. Heavy-duty operation control: Four load-sensitive pumps output differentiated flow rates according to the load requirements of each actuator. The controller dynamically optimizes the pump output based on the engine's real-time torque and speed parameters, and allocates flow rates according to the actuator's action priority. The actuator action priority is ordered in the order of hoisting, luffing, telescopic, steering, and spreader operation. Higher priority actions receive hydraulic flow first, while lower priority actions adaptively adjust their operating speed based on the remaining flow rate to ensure the stability of core actions under heavy load. When a combined action is required (such as hoisting + steering), the system automatically allocates pumps to different hydraulic circuits, with each circuit not interfering with the others, ensuring the smoothness and accuracy of the action. When a single high-speed / high-pressure action is required, the system can combine the flow rates of multiple pumps to meet the needs of high-flow and high-pressure operations.

[0055] Specifically, in the electronic control system, when the load pressure detected by the sensor exceeds a high threshold, multiple actuators may operate simultaneously. The LS port pressures of different actuators are all at high values, resulting in differentiated flow demands. The controller receives dynamic parameters of engine torque and speed in real time, dynamically matching the pump output with the engine's maximum available power as the upper limit. Simultaneously, in the hydraulic system, under heavy loads, the reach stack bears a large load, and multiple actuators may operate simultaneously, resulting in high pressures at each LS port. The core function of the pressure feedback shuttle valve assembly is to filter the highest load pressure in each operating link. Pressure feedback shuttle valve I continuously filters the highest pressure of the multi-way valve (main operation) and the spreader oil supply valve assembly, transmitting it to the load-sensitive pump II to ensure the core pressure signals for the main operation and spreader operation. Shuttle valve II continuously filters the highest pressure of the multi-way valve (main operation) and steering gear, transmitting it to load-sensitive pumps III and IV to ensure the core pressure signals for main operation and steering operation. The controller combines the highest pressure signal fed back by the shuttle valve group with the engine's real-time torque and speed parameters to differentiate the displacement of the four pumps and allocate flow according to the priority of hoisting > luffing > telescoping > steering > spreader operation. During compound operations, the pressure feedback shuttle valve group provides independent highest pressure signals to the load-sensitive pump groups of different operation links, allowing the load-sensitive pump groups to be distributed to different hydraulic circuits without interference. At the same time, during a single heavy-duty or high-speed operation, the unified high-pressure signal fed back by the pressure feedback shuttle valve group triggers the confluence of multiple pumps to meet the requirements of large flow and high pressure.

[0056] In the method of using a multi-pump flow distribution and merging energy-saving hydraulic control system for heavy-duty reach stackers, the division of no-load, medium-load, and heavy-load operating conditions is based on the comparison between the real-time load pressure of the system and the preset pressure threshold stored in the controller. The controller automatically judges the operating condition and switches the control strategy according to the data collected by the pressure sensor to achieve adaptive switching of operating conditions. If the hydraulic load changes suddenly (such as a sudden increase from medium load to heavy load), the pressure and flow sensors will collect the changed parameters in real time and transmit them to the controller. The controller immediately re-analyzes the engine parameters and the new load parameters, and adjusts the number and displacement of the pump group. In all operating conditions, the pressure feedback shuttle valve group feeds back the highest load pressure of each actuator to the controller and the pump group LS valve in real time. The controller combines the pressure signal to fine-tune the output pressure of the pump, ensuring that the pump outlet pressure is only a constant difference higher than the load pressure, reducing pressure loss, and further optimizing engine power consumption. In addition, if the engine torque and speed fluctuate due to load changes, the ECU will transmit parameters to the controller in real time. If the available engine power is insufficient, the controller will reduce the flow supply to non-core actuators, prioritize core actions, and avoid engine overload shutdown.

[0057] This invention discloses an energy-saving hydraulic control system and method for heavy-duty reach stackers with multi-pump flow distribution and merging. Four load-sensitive pumps are used as core power components. A multi-way valve, a spreader oil supply valve group, and the LS port of the steering gear are connected to the corresponding pump group via two pressure feedback shuttle valve groups. Combined with pressure and flow sensors and a controller, real-time communication between the engine and hydraulic system is achieved via a CAN bus. The controller performs condition-specific regulation of the pump group based on collected load data and engine parameters, including no-load full-displacement merging, medium-load selective pump start-up, and heavy-load differentiated flow output. Simultaneously, the LS valve controls the constant difference between the pump output pressure and the load pressure, and the multi-way valve precisely regulates the cylinder action. This solution achieves on-demand flow distribution and deep power matching between the engine and pump group, significantly reducing pressure and flow losses. It improves operational efficiency by enabling rapid response of luffing and boom extension under no-load conditions while reducing energy consumption under medium and heavy-load conditions, balancing equipment performance and energy saving, and is suitable for the high-load operation requirements of port reach stackers.

[0058] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0059] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features found in other embodiments but not others, combinations of features from different embodiments are also within the scope of protection of this invention and form different embodiments. For example, in the embodiments described above, those skilled in the art can use them in combination based on known technical solutions and the technical problems to be solved by this application.

[0060] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. An energy-saving hydraulic control system for heavy-duty reach stackers with multi-pump flow distribution and merging, characterized in that: The system includes a load-sensitive pump assembly, the output of which is connected to a multi-way valve (3), a spreader oil supply valve assembly (14), and a steering gear (15). The multi-way valve (3) is connected to a telescopic cylinder (6) and a luffing cylinder (7) via a telescopic balance valve assembly (4) and a luffing balance valve assembly (5), respectively. The LS ports of the multi-way valve (3), the spreader oil supply valve assembly (14), and the steering gear (15) are connected to the LS port of the load-sensitive pump assembly via a pressure feedback shuttle valve assembly. The system also includes a controller, the input of which is connected to a pressure sensor and a flow sensor. The pressure sensor and the flow sensor collect pressure and flow demand data of each actuator in the system in real time. The output of the controller communicates with the engine ECU via a CAN bus. The engine provides power to the load-sensitive pump assembly. The pressure feedback shuttle valve group includes a two-way shuttle valve network consisting of pressure feedback shuttle valve I (2.1) and pressure feedback shuttle valve II (2.2), which is used to collect the highest load pressure of the system and feed it back to the load sensitive pump group. The load sensitive pump group includes four load sensitive pumps with the same structure, namely load sensitive pump I (1.1), load sensitive pump II (1.2), load sensitive pump III (1.3) and load sensitive pump IV (1.4). The input end of pressure feedback shuttle valve I (2.2) is connected to the LS port of multi-way valve (3) and the LS port of spreader oil supply valve group (14), and the output end is connected to the LS port of load sensitive pump II (1.2). The input end of pressure feedback shuttle valve II (2.2) is connected to the LS port of multi-way valve (3) and the LS port of diverter (15), and the output end is connected to the LS ports of load sensitive pump III (1.3) and load sensitive pump IV (1.4). The LS port of load sensitive pump I (1.1) is directly connected to the LS port of multi-way valve (3).

2. The energy-saving hydraulic control system for heavy-duty reach stackers with multi-pump flow distribution and merging as described in claim 1, characterized in that: The load-sensitive pump includes a variable pump (8), an LS valve (9), a pressure shut-off valve (10), and a variable piston (11).

3. The energy-saving hydraulic control system for heavy-duty reach stackers with multi-pump flow distribution and merging as described in claim 1, characterized in that: The multi-way valve (3) includes a three-position seven-way proportional pilot valve (12) and a two-position three-way proportional valve (13). The pilot pressure is fed back to the three-position seven-way proportional pilot valve (12) through the two-position three-way proportional valve (13), and the opening size and direction of its main valve port are controlled by the three-position seven-way proportional pilot valve (12), thereby controlling the flow rate and direction of hydraulic oil flowing into the telescopic cylinder (6) and the amplitude-changing cylinder (7), so as to realize the adjustment of cylinder speed and telescopic action.

4. The energy-saving hydraulic control system for heavy-duty front-end cranes with multi-pump flow distribution and merging as described in claim 1, characterized in that: Both the telescopic balance valve group (4) and the luffing balance valve group (5) are equipped with directional control valves and cartridge valves. Through the coordinated action of the directional control valves and cartridge valves, the luffing and telescopic functions of the telescopic cylinder and the luffing cylinder are realized, while ensuring the stability of the cylinder action.

5. The energy-saving hydraulic control system for heavy-duty front-end cranes with multi-pump flow distribution and merging as described in claim 1, characterized in that: The load-sensitive pump unit is connected to the engine through two power take-off ports of the gearbox. The engine provides power to the load-sensitive pump unit. The controller dynamically adjusts the displacement and load of the load-sensitive pump unit according to the engine's real-time torque and speed parameters to achieve power matching between the engine and the main pump.

6. The energy-saving hydraulic control system for heavy-duty reach stackers with multi-pump flow distribution and merging as described in claim 1, characterized in that: The pressure and flow sensors are installed in the hydraulic circuits of each actuator to collect pressure and flow demand data of the telescopic cylinder, luffing cylinder, spreader oil supply valve group and steering gear in real time, and transmit the data to the controller. The controller has pre-stored pressure thresholds for working condition determination and actuator action priority rules.

7. A method of using a multi-pump flow distribution and merging energy-saving hydraulic control system for heavy-duty reach stackers, applied to the multi-pump flow distribution and merging energy-saving hydraulic control system for heavy-duty reach stackers as described in any one of claims 1-6, characterized in that: Based on real-time data collected by pressure and flow sensors, and combined with engine parameters, the controller performs differentiated control of the load-sensitive pump set to adapt to three operating conditions: no-load, medium-load, and heavy-load. Specifically, this includes the following steps: S1, No-load operation control: The LS port pressure of the steering gear (15) and the spreader oil supply valve group (14) is close to 0. After the pressure feedback shuttle valve I (2.1) and pressure feedback shuttle valve II (2.2) compare the pressure, they trigger the four load-sensitive pumps to run at full displacement to quickly establish the system pressure. The hydraulic oil is delivered to the telescopic cylinder (6) and the luffing cylinder (7) after the multi-way valve is combined, so as to realize the rapid response of luffing and boom extension. S2, Medium-load operating condition control: The controller receives pressure and flow data from each actuator. Based on the preset algorithm and engine power matching principle, it selectively activates the partial load sensitive pump through the pressure signal transmission of pressure feedback shuttle valve I (2.1) and pressure feedback shuttle valve II (2.2), and precisely adjusts the pump's output displacement. The non-essential load sensitive pump automatically shuts down, so that the engine operates in the high-efficiency power range. S3, Heavy-duty operation control: Four load-sensitive pumps output differentiated flow rates according to the load requirements of each actuator. The controller dynamically optimizes the pump output based on the engine's real-time torque and speed parameters, allocates flow rates according to the actuator's action priority, distributes pumps to different hydraulic circuits during compound actions, and achieves flow merging of pumps during single actions.

8. The method of using the energy-saving hydraulic control system for heavy-duty front-end cranes with multi-pump flow distribution and merging as described in claim 7, characterized in that: In step S2, the controller uses the engine's high-efficiency zone as a constraint and calculates the hydraulic power P based on the real-time pressure p and flow rate Q, P=pQ / 60, ensuring that the total power of the pump set does not exceed the engine's available power. When only light-load main operation needs to be completed, only load-sensitive pump I (1.1) needs to be turned on to meet the flow requirements. When lifting medium-weight loads, the controller transmits pressure signals through pressure feedback shuttle valve I (2.1) and simultaneously turns on load-sensitive pump I (1.1) and load-sensitive pump II (1.2) to achieve flow superposition. When steering + main operation compound operation needs to be completed, the controller compares the pressure signals through pressure feedback shuttle valve II (2.2) and selectively turns on load-sensitive pump III (1.3) and / or load-sensitive pump IV (1.4) to supplement the flow of the steering gear.

9. The method of using the energy-saving hydraulic control system for heavy-duty front-end cranes with multi-pump flow distribution and merging as described in claim 7, characterized in that: In step S3, the action priority of the actuator is sorted in the order of hoisting, luffing, telescoping, steering, and spreader operation. Actions with higher priority get hydraulic flow first, while actions with lower priority adjust their operating speed adaptively according to the remaining flow to ensure the stability of core actions under heavy load.

10. The method of using the energy-saving hydraulic control system for heavy-duty front-end cranes with multi-pump flow distribution and merging as described in claim 7, characterized in that: The division of no-load, medium-load, and heavy-load operating conditions is based on the comparison between the real-time load pressure of the system and the preset pressure threshold. The controller automatically judges the operating condition and switches the control strategy according to the data collected by the pressure sensor, so as to realize the adaptive switching of operating conditions.

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