Hydraulic system based on load-sensitive self-adaptive preheating and engineering machinery

Abstract

The utility model relates to hydraulic preheat technical field provides a kind of based on load sensitive self-adapting preheat's hydraulic system and engineering machinery, preheat module is set to the oil outlet communication of plunger pump, load sensitive control oil port of setting and distribution valve, the oil outlet of preheat module, the load sensitive module connected with the load sensitive control port of plunger pump, preheat module directly takes oil from plunger pump oil outlet, realizes oil heating when low temperature start by independent circuit, further improves heating rate, working efficiency, and avoid main circuit pollution or pressure fluctuation, improve cold start reliability;Load sensitive module real-time perception both ends oil inlet transmission load pressure, analysis preheat power demand (preheat oil flow rate) / system load pressure demand, dynamically adjust the output flow and pressure of plunger pump, avoid redundant energy consumption, significantly reduce power consumption;Simple structure, low cost.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic preheating technology, and in particular to a hydraulic system and engineering machinery based on load-sensitive adaptive preheating. Background Technology

[0002] When construction machinery is in operation, its hydraulic system needs to be maintained at a suitable temperature so that the hydraulic fluid has a viscosity suitable for flow in the pipeline. When the construction machinery is first started, the hydraulic fluid in its system is close to the ambient temperature, requiring a warm-up operation for a corresponding period of time based on the hydraulic fluid temperature, so that the hydraulic fluid temperature reaches the requirements for normal operation of the hydraulic system.

[0003] In conventional hydraulic schematics for existing construction machinery, if the hydraulic system needs to be preheated, the system's cooling is stopped while steering or working in place to allow the hydraulic oil to raise its temperature using its own heat. This method not only takes a long time and reduces work efficiency, but also, operating the system at high power for preheating when the hydraulic oil is too viscous at low temperatures will overload the pump and other hydraulic components, reducing the system's lifespan.

[0004] Therefore, a preheating solution has been added to the existing market that uses a combination of electro-proportional valves and unloading valves in conjunction with priority valves and relief valves in the main circuit to preheat the hydraulic oil. Its core is to achieve the circulation and heating of hydraulic oil through "forced throttling and unloading + pressure differential control of relief valve". The warm-up process requires multi-stage linkage of controller → electro-proportional valve → unloading valve → priority valve → relief valve. The oil temperature rise response is slow, and the structure is complex and the cost is high. Utility Model Content

[0005] This invention provides a hydraulic system and engineering machinery based on load-sensitive adaptive preheating, which solves the technical problems of existing hydraulic oil preheating systems, such as complex structure, slow oil temperature rise response, and high cost.

[0006] To solve the above technical problems, this utility model provides a hydraulic system based on load-sensitive adaptive preheating, including a piston pump, a distribution valve, a load-sensitive module, and a preheating module connected to the piston pump; the oil outlet of the piston pump is connected to the oil inlet of the distribution valve and the oil inlet of the preheating module, and its load-sensitive control port is connected to the oil outlet of the load-sensitive module; one end of the oil inlet of the load-sensitive module is connected to the load-sensitive control oil port of the distribution valve, and the other end of the oil inlet is connected to the LS port of the preheating module;

[0007] The LS port of the preheating module and the load-sensitive control port of the distribution valve transmit load pressure from the two inlets of the load-sensitive module. Adjusting the outlet pressure of the load-sensitive module drives the plunger pump to adjust the outlet flow rate, thereby adjusting the preheating oil flow rate of the preheating module.

[0008] This basic solution includes a preheating module connected to the outlet of the plunger pump, and a load-sensitive module connected to the load-sensitive control port of the distribution valve, the outlet of the preheating module, and the load-sensitive control port of the plunger pump. The preheating module draws oil directly from the plunger pump outlet and heats the oil during low-temperature starts through an independent circuit, further improving the heating rate and working efficiency, while avoiding contamination or pressure fluctuations in the main circuit and enhancing cold-start reliability. The load-sensitive module senses the load pressure transmitted through the two inlets in real time, analyzes the preheating power requirement (preheating oil flow rate) / system load pressure requirement, and dynamically adjusts the output flow and pressure of the plunger pump to avoid unnecessary energy consumption and significantly reduce power consumption. The structure is simple and the cost is low.

[0009] In a further embodiment, the preheating module includes a first electro-proportional valve, a first directional valve, and a first throttle orifice. The first electro-proportional valve is connected to the control terminal of the first directional valve. The oil inlet of the first directional valve is connected to the oil outlet of the plunger pump, and the oil outlet serves as the LS port, connected to the other end oil inlet of the load-sensitive module. The oil inlet of the first throttle orifice is connected to the oil outlet of the first directional valve, and the oil outlet is connected to the oil tank.

[0010] The first directional valve has a built-in second throttle orifice, and the opening degree of the second throttle orifice is proportional to the output of the first electro-proportional valve.

[0011] This solution uses a first directional valve and a first throttling orifice as the preheating channel. The preheating power is controlled by the electrical control properties of the first electro-proportional valve. Since the opening of the first directional valve is controlled by the first electro-proportional valve, the opening of the second throttling orifice inside it is also controlled by the first electro-proportional valve. Thus, by adjusting the current of the first electro-proportional valve, the opening of the second throttling orifice in the first directional valve can be adjusted. The adjustable opening of the second throttling orifice, combined with the fixed opening of the first throttling orifice, achieves adjustable heating function, fully meeting the preheating requirements under different flow rates. The first electro-proportional valve, the first directional valve, and the first throttling orifice have a simple structure, effectively reducing the equipment and installation costs of the preheating function.

[0012] In a further embodiment, the load-sensitive module includes a first shuttle valve, which includes a first oil inlet, a second oil inlet, and an oil outlet. The first oil inlet of the first shuttle valve is connected to the load-sensitive control oil port of the distribution valve, the second oil inlet is connected to the oil outlet of the preheating module, and the oil outlet is connected to the load-sensitive control port of the plunger pump.

[0013] In this scheme, the first oil inlet of the first shuttle valve is connected to the load-sensitive control port of the distribution valve, the second oil inlet is connected to the oil outlet of the preheating module, and the oil outlet is connected to the load-sensitive control port of the plunger pump. The shuttle valve automatically compares the load pressure of the distribution valve and the preheating module, detects and transmits load pressure changes in real time, and enables the plunger pump to quickly adjust its output and quickly achieve hydraulic oil heating.

[0014] In a further embodiment, a temperature control module is also included, which includes a main controller and a temperature sensor. The main controller is electrically connected to the preheating module and the temperature sensor. The temperature sensor is installed near the oil tank, and its detection end is inserted into the oil in the oil tank.

[0015] This solution is based on the preheating module, which is configured with a corresponding temperature control module. The temperature sensor provides real-time feedback on the oil preheating status, which assists the main controller in controlling the preheating progress and realizing remote automated preheating control.

[0016] In a further embodiment, a pilot oil supply valve is also included, the inlet of which is connected to the outlet of the plunger pump, and the outlet is connected to the pilot pressure oil supply port of the distribution valve; the outlet of the pilot oil supply valve is also connected to the inlet of the first directional valve.

[0017] After the first electro-proportional valve is activated, it operates in the upper position. The pilot oil from the outlet of the pilot oil supply valve enters the first electro-proportional valve. The pilot oil pressure generated by the pilot oil output from the outlet of the first electro-proportional valve acts on the control end of the first directional valve to execute the opening control of the first directional valve.

[0018] This solution controls the opening of the first directional valve by controlling the pilot oil output from the outlet of the first electro-proportional valve. The opening of the preheating oil circuit is steplessly adjusted by an electrical signal, thereby precisely controlling the preheating flow rate and assisting the first directional valve (second throttle orifice) in adjusting the preheating power.

[0019] In a further embodiment, the distribution valve includes at least one set of working ports, which are connected to hydraulic actuators, including boom cylinders and bucket cylinders.

[0020] In a further embodiment, a first check valve is also included, the inlet of which is connected to the outlet of the plunger pump, and the outlet is connected to the inlet of the distribution valve and the inlet of the preheating module.

[0021] This design incorporates a first check valve between the distribution valve and the plunger pump to prevent oil backflow, protect the plunger pump, and maintain system stability.

[0022] In a further embodiment, the first electro-proportional valve includes a two-position three-way electro-proportional valve.

[0023] In a further embodiment, the first directional valve includes a two-position two-way directional valve.

[0024] This solution uses a two-position three-way proportional valve and a two-position two-way directional valve to construct a preheating module. Based on dynamic switching and proportional regulation, it can reduce useless power consumption.

[0025] This utility model also provides an engineering machinery, including an engineering machinery body and a hydraulic system based on load-sensitive adaptive preheating as described above, wherein the hydraulic system is disposed on the engineering machinery body. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a hydraulic system based on load-sensitive adaptive preheating provided in Embodiment 1 of this utility model;

[0027] Figure 2 This is provided in Embodiment 1 of the present utility model. Figure 1 Enlarged view of the preheating module;

[0028] Among them: plunger pump 1, distribution valve 2, load sensitive module 3, preheating module 4, first electro-proportional valve 41, first reversing valve 42, first throttle orifice 43, second throttle orifice 44; temperature sensor 5, pilot oil supply valve 6, boom cylinder 7, bucket cylinder 8, first check valve 9. Detailed Implementation

[0029] The embodiments of this utility model are described in detail below with reference to the accompanying drawings. The embodiments are given for illustrative purposes only and should not be construed as limiting the utility model. The accompanying drawings are for reference and illustration only and do not constitute a limitation on the scope of patent protection of this utility model, because many changes can be made to this utility model without departing from the spirit and scope of this utility model.

[0030] Example 1

[0031] This utility model provides a hydraulic system based on load-sensitive adaptive preheating, such as... Figure 1 As shown, in this embodiment, a plunger pump 1 is included, along with a distribution valve 2, a load-sensitive module 3, and a preheating module 4 connected to the plunger pump 1. The oil outlet of the plunger pump 1 is connected to the oil inlet of the distribution valve 2 and the oil inlet P of the preheating module 4, and its load-sensitive control port is connected to the oil outlet of the load-sensitive module 3. One end of the oil inlet of the load-sensitive module 3 is connected to the load-sensitive control port of the distribution valve 2, and the other end of the oil inlet is connected to the LS port of the preheating module 4. The oil outlet T of the preheating module 4 is connected to the oil tank.

[0032] The LS port of the preheating module 4 and the load-sensitive control port of the distribution valve 2 transmit load pressure from the two inlets of the load-sensitive module 3, respectively. Adjusting the outlet pressure of the load-sensitive module 3 drives the plunger pump 1 to adjust the outlet flow rate, thereby adjusting the preheating oil flow rate of the preheating module 4.

[0033] The oil inlet of the plunger pump 1 is connected to the oil tank.

[0034] In this embodiment, see Figure 2 The preheating module 4 includes a first electro-proportional valve 41, a first directional valve 42, and a first throttle orifice 43. The first electro-proportional valve 41 is connected to the control terminal of the first directional valve 42. The oil inlet of the first directional valve 42 is connected to the oil outlet of the plunger pump 1, and the oil outlet is connected as the LS port to the other end of the oil inlet of the load-sensitive module 3. The oil inlet of the first throttle orifice 43 is connected to the oil outlet of the first directional valve 42, and the oil outlet is connected to the oil tank.

[0035] The first reversing valve 42 has a built-in second throttle orifice 44, and the opening degree of the second throttle orifice 44 is proportional to the output of the first electro-proportional valve 41.

[0036] In this embodiment, the first electro-proportional valve 41 includes a two-position three-way electro-proportional valve.

[0037] In this embodiment, the first reversing valve 42 includes a two-position two-way reversing valve.

[0038] In this embodiment, a preheating module 4 is constructed using a two-position three-way proportional valve and a two-position two-way directional valve. Based on dynamic switching and proportional adjustment, unnecessary power consumption can be reduced.

[0039] In this embodiment, a first reversing valve 42 and a first throttling orifice 43 are used as preheating channels. The preheating power is controlled by the electrical control properties of the first electro-proportional valve 41. Since the opening of the first reversing valve 42 is controlled by the first electro-proportional valve 41, the opening of the second throttling orifice 44 inside it is also controlled by the first electro-proportional valve 41. Thus, by adjusting the current of the first electro-proportional valve 41, the opening of the second throttling orifice 44 in the first reversing valve 42 can be adjusted. The adjustable opening of the second throttling orifice 44, combined with the fixed opening of the first throttling orifice 43, achieves adjustable heating function, fully meeting the preheating requirements under different flow rates. The first electro-proportional valve 41, the first reversing valve 42, and the first throttling orifice 43 have simple structures, effectively reducing the equipment cost and installation cost of the preheating function.

[0040] In this embodiment, the load-sensitive module 3 includes a first shuttle valve, which includes a first oil inlet, a second oil inlet, and an oil outlet. The first oil inlet of the first shuttle valve is connected to the load-sensitive control oil port of the distribution valve 2, the second oil inlet is connected to the oil outlet of the preheating module 4, and the oil outlet is connected to the load-sensitive control port of the plunger pump 1.

[0041] The first oil inlet of the first shuttle valve can also be connected to the LSN port of other hydraulic systems as needed for load-sensitive control.

[0042] In this embodiment, the first oil inlet of the first shuttle valve is connected to the load-sensitive control port of the distribution valve 2, the second oil inlet is connected to the oil outlet of the preheating module 4, and the oil outlet is connected to the load-sensitive control port of the plunger pump 1. The shuttle valve automatically compares the load pressure of the distribution valve 2 and the preheating module 4, detects and transmits load pressure changes in real time, and enables the plunger pump 1 to quickly adjust its output and quickly achieve hydraulic oil heating.

[0043] In this embodiment, a temperature control module is also included. The temperature control module includes a main controller and a temperature sensor 5. The main controller is electrically connected to the preheating module 4 and the temperature sensor 5. The temperature sensor 5 is installed near the oil tank, and its detection end is inserted into the oil in the oil tank.

[0044] The main controller includes, but is not limited to, the whole machine controller or PLC controller, which are conventional controllers in this field and are not shown in the figure.

[0045] In this embodiment, a corresponding temperature control module is configured based on the preheating module 4. The temperature sensor 5 provides real-time feedback on the oil preheating status, assisting the main controller in controlling the preheating progress and realizing remote automated preheating control.

[0046] In this embodiment, a pilot oil supply valve 6 is also included. The oil inlet of the pilot oil supply valve 6 is connected to the oil outlet of the plunger pump 1, and the oil outlet is connected to the pilot pressure oil supply port of the distribution valve 2. The oil outlet of the pilot oil supply valve 6 is also connected to the oil inlet PX of the first reversing valve 42.

[0047] After the first electro-proportional valve 41 is activated, it operates in the upper position. The pilot oil from the outlet of the pilot oil supply valve 6 enters the first electro-proportional valve 41. The pilot oil pressure generated by the pilot oil output from the outlet of the first electro-proportional valve 41 acts on the control end of the first directional valve 42 to execute the opening control of the first directional valve 42.

[0048] The pilot oil supply valve 6 in this embodiment is a prior art technique and will not be described in detail here.

[0049] In this embodiment, the opening degree of the first directional valve 42 is controlled by controlling the pilot oil output from the outlet of the first electro-proportional valve 41. The opening degree of the preheating oil circuit is steplessly adjusted by the electrical signal, thereby accurately controlling the preheating flow rate and assisting the first directional valve 42 (second throttle orifice 44) in adjusting the preheating power.

[0050] In this embodiment, the distribution valve 2 includes at least one set of working ports (such as...). Figure 1 (A1, B1 and A2, B2), the working oil port is connected to the hydraulic actuator, which includes, but is not limited to, boom cylinder 7 and bucket cylinder 8.

[0051] Among them, the distribution valve 2 is also connected to other systems through its oil inlet P2. If it is necessary to preheat other oil circuits / tanks, the preheating module 4 can be connected as needed, or a separate set of "preheating module 4 + load sensitive module 3 + temperature control module" can be set up.

[0052] In this embodiment, a first check valve 9 is also included. The oil inlet of the first check valve 9 is connected to the oil outlet of the plunger pump 1, and the oil outlet is connected to the oil inlet of the distribution valve 2 and the oil inlet of the preheating module 4.

[0053] In this embodiment, a first check valve 9 is provided between the distribution valve 2 and the plunger pump 1 to prevent oil backflow, protect the plunger pump 1, and maintain system stability.

[0054] The working principle of this embodiment is as follows:

[0055] (1) Normal operation, without low-temperature preheating

[0056] When the working device is operated, pilot oil from pilot supply valve 6 enters distribution valve 2 through pilot pressure supply port XDP, and distribution valve 2 opens its control valve port. Subsequently, the load pressure signal is output to the first shuttle valve through the load-sensitive control port (LS port) of distribution valve 2, which pushes the first shuttle valve to open and feeds back the pressure signal to the load-sensitive control port (X2 port) of plunger pump 1, causing plunger pump 1 to gradually increase its displacement and output hydraulic oil. The pressurized oil from plunger pump 1 is output from the outlet port P2 of plunger pump 1, flows into the inlet port of distribution valve 2 through the first check valve 9, and finally enters the working cylinder to realize the operation of the working device.

[0057] (2) Perform oil preheating

[0058] When performing low-temperature preheating, the main controller controls the first electro-proportional valve 41 to be energized, and the first electro-proportional valve 41 operates in the upper position; at this time, the pilot oil from the pilot oil supply valve 6 enters the first directional valve 42 through the first electro-proportional valve 41, controlling the first directional valve 42 to switch to the left position.

[0059] The load pressure from the main oil circuit of the system flows through the oil inlet P of the preheating module 4 and through the first directional valve 42 to be output from the LS port of the preheating module 4, feeding back the load signal to the load sensitive control port (X2 port) of the plunger pump 1, so that the plunger pump 1 adjusts the displacement to output pressure oil.

[0060] At the same time, the high-flow-rate pressurized oil passes through the second throttle hole 44 and the first throttle hole 43 inside the first directional valve 42 in sequence, converting the energy of the pressurized oil into heat energy and realizing the heating of the hydraulic oil.

[0061] The main controller outputs different currents to the first electro-proportional valve 41 to control the pilot oil pressure at its outlet, thereby controlling the pilot switching pressure of the first directional valve 42. This adjusts the opening of the second throttle orifice 44 inside the first directional valve 42. The second throttle orifice 44 and the fixed first throttle orifice 43 form a pressure drop regulation, which can feed back different load pressure signals to the plunger pump 1 to achieve different energy conversion power and different preheating flow rates. In other words, different flow rates and pressures can be adapted by adjusting different input currents.

[0062] The specific preheating process is as follows:

[0063] Step 1: After the machine starts in a low-temperature environment, the main controller temporarily stops inputting current to the first proportional valve 41, allowing the machine to idle for a certain period of time (e.g., for 3 minutes) to preheat the engine or motor and reach the normal operating state of the machine.

[0064] Step 2: The main controller outputs a small current to the first electro-proportional valve 41. At this time, the first electro-proportional valve 41 is in the upper position, causing the first directional valve 42 to open with a small opening. This feeds back a small load signal to the plunger pump 1, which outputs pressurized oil with a small displacement. When the pressurized oil passes through the first directional valve 42 and the first throttle orifice 43, a small heating power can be achieved. Maintaining this current for a certain period of time (e.g., for 5 minutes) can provide better lubrication for the system pipelines, preparing for full-power heating.

[0065] Step 3: The main controller gradually increases the current input to the first proportional valve, reaching the maximum current within a certain time (e.g., within 5 minutes). This causes the first directional valve 42 to open to its maximum degree. Under the action of the first throttle orifice 43, the maximum load signal is fed back to the piston pump 1, causing the piston pump 1 to output pressurized oil at its maximum displacement. When the pressurized oil passes through the first directional valve 42 and the first throttle orifice 43, the maximum heating power is achieved. This state continues until the hydraulic oil temperature reaches the predetermined temperature (until the temperature sensor 5 reports that the hydraulic oil temperature has reached 5 degrees Celsius), at which point step 4 is executed.

[0066] Step 4: When the temperature sensor 5 reports to the main controller that the hydraulic oil temperature has reached the predetermined temperature, the main controller gradually reduces the input current of the first electro-proportional valve 41, and the area of ​​the second throttle orifice 44 inside the second directional valve also decreases accordingly, thereby gradually reducing the heating power until it is shut off.

[0067] This basic scheme includes a preheating module 4 connected to the oil outlet of the plunger pump 1, and a load-sensitive module 3 connected to the load-sensitive control port of the distribution valve 2, the oil outlet of the preheating module 4, and the load-sensitive control port of the plunger pump 1. The preheating module 4 directly draws oil from the oil outlet of the plunger pump 1 and heats the oil during low-temperature startup through an independent circuit, further improving the heating rate and working efficiency, while avoiding contamination or pressure fluctuations in the main circuit and enhancing cold-start reliability. The load-sensitive module 3 senses the load pressure transmitted through the oil inlets at both ends in real time, analyzes the preheating power requirement (preheating oil flow rate) / system load pressure requirement, and dynamically adjusts the output flow and pressure of the plunger pump 1 to avoid unnecessary energy consumption and significantly reduce power consumption. The structure is simple and the cost is low.

[0068] Example 2

[0069] This utility model embodiment also provides an engineering machinery, including an engineering machinery body and a hydraulic system based on load-sensitive adaptive preheating as described in Embodiment 1 above, wherein the hydraulic system is disposed on the engineering machinery body.

[0070] Among them, the main body of the construction machinery includes, but is not limited to, loaders and graders.

[0071] The above embodiments are preferred embodiments of the present utility model, but the embodiments of the present utility model are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present utility model shall be considered equivalent substitutions and shall be included within the protection scope of the present utility model.

Claims

1. A hydraulic system based on load-sensitive adaptive preheating, characterized in that: The system includes a plunger pump, a distribution valve, a load-sensitive module, and a preheating module connected to the plunger pump; the outlet of the plunger pump is connected to the inlet of the distribution valve and the inlet of the preheating module, and its load-sensitive control port is connected to the outlet of the load-sensitive module; one end of the load-sensitive module's inlet is connected to the load-sensitive control port of the distribution valve, and the other end of the inlet is connected to the LS port of the preheating module. The LS port of the preheating module and the load-sensitive control port of the distribution valve transmit load pressure from the two inlets of the load-sensitive module. Adjusting the outlet pressure of the load-sensitive module drives the plunger pump to adjust the outlet flow rate, thereby adjusting the preheating oil flow rate of the preheating module.

2. The hydraulic system based on load-sensitive adaptive preheating as described in claim 1, characterized in that: The preheating module includes a first electro-proportional valve, a first directional valve, and a first throttle orifice. The first electro-proportional valve is connected to the control terminal of the first directional valve. The oil inlet of the first directional valve is connected to the oil outlet of the plunger pump. The oil outlet serves as the LS port and is connected to the other end of the oil inlet of the load-sensitive module. The oil inlet of the first throttle orifice is connected to the oil outlet of the first directional valve, and the oil outlet is connected to the oil tank. The first directional valve has a built-in second throttle orifice, and the opening degree of the second throttle orifice is proportional to the output of the first electro-proportional valve.

3. The hydraulic system based on load-sensitive adaptive preheating as described in claim 1, characterized in that: The load-sensitive module includes a first shuttle valve, which includes a first oil inlet, a second oil inlet, and an oil outlet. The first oil inlet of the first shuttle valve is connected to the load-sensitive control oil port of the distribution valve, the second oil inlet is connected to the oil outlet of the preheating module, and the oil outlet is connected to the load-sensitive control port of the plunger pump.

4. A hydraulic system based on load-sensitive adaptive preheating as described in claim 2, characterized in that: It also includes a temperature control module, which includes a main controller and a temperature sensor. The main controller is electrically connected to the preheating module and the temperature sensor. The temperature sensor is installed near the oil tank, and its detection end is inserted into the oil in the oil tank.

5. A hydraulic system based on load-sensitive adaptive preheating as described in claim 4, characterized in that: It also includes a pilot oil supply valve, the inlet of which is connected to the outlet of the plunger pump, and the outlet of which is connected to the pilot pressure oil supply port of the distribution valve; the outlet of the pilot oil supply valve is also connected to the inlet of the first directional valve. After the first electro-proportional valve is activated, it operates in the upper position. The pilot oil from the outlet of the pilot oil supply valve enters the first electro-proportional valve. The pilot oil pressure generated by the pilot oil output from the outlet of the first electro-proportional valve acts on the control end of the first directional valve to execute the opening control of the first directional valve.

6. A hydraulic system based on load-sensitive adaptive preheating as described in claim 1, characterized in that: The distribution valve includes at least one set of working ports, which are connected to hydraulic actuators, including boom cylinders and bucket cylinders.

7. A hydraulic system based on load-sensitive adaptive preheating as described in claim 1, characterized in that: It also includes a first check valve, the oil inlet of which is connected to the oil outlet of the plunger pump, and the oil outlet is connected to the oil inlet of the distribution valve and the oil inlet of the preheating module.

8. A hydraulic system based on load-sensitive adaptive preheating as described in claim 2, characterized in that: The first electro-proportional valve includes a two-position three-way electro-proportional valve.

9. A hydraulic system based on load-sensitive adaptive preheating as described in claim 2, characterized in that: The first directional valve includes a two-position two-way directional valve.

10. An engineering machinery, characterized in that: It includes a construction machinery body and a hydraulic system based on load-sensitive adaptive preheating as described in any one of claims 1 to 9, wherein the hydraulic system is disposed on the construction machinery body.

Images