CN105714872B - A kind of pressure and the adjustable hydraulic energy recovery of capacity and stocking system and its method of work - Google Patents

Abstract

The invention provides a hydraulic energy recovery and storage system with adjustable pressure and capacity, comprising: an oil cylinder (1), a variable hydraulic pump (2), a hydraulic switch network, a hydraulic cylinder (6), and a hydraulic accumulator (7) , a pneumatic accumulator (9), a three-position three-way valve (20) and a two-position three-way valve (21); wherein, the variable hydraulic pump (2) is connected to the oil cylinder (1), and the output end is connected to the hydraulic switch network; the hydraulic switch The network is connected with the hydraulic accumulator (7); the hydraulic accumulator (7) is an inflatable hydraulic tank with a lower hydraulic chamber and an upper compressed air chamber; the compressed air chamber of the hydraulic accumulator (7) passes through a three-position three-way The valve (20) communicates with the pneumatic accumulator (9); the hydraulic cylinder (6) communicates with the hydraulic switch network. The energy recovery unit composed of a hydraulic accumulator (7) and a pneumatic accumulator (9) can realize dual-parameter adjustment of recovery pressure and recovery energy capacity, ensuring stable operation of the system while maximizing energy recovery and utilization efficiency, which can greatly reduce fuel consumption and emissions. The present invention also provides a working method based on the hydraulic energy recovery and storage system with adjustable pressure and capacity.

Description

A hydraulic energy recovery and storage system with adjustable pressure and capacity and its working method

technical field

The invention relates to a hydraulic energy recovery and storage system with adjustable pressure and capacity and a working method thereof.

Background technique

With the continuous increase of oil prices and the increasing impact of exhaust emissions on the environment, energy conservation and emission reduction have become the focus of research. After more than ten years of development, the application of hybrid technology in passenger vehicles has become increasingly mature, and various models emerge in endlessly. Due to the small number of engineering vehicles compared with passenger vehicles, the energy-saving and emission-reduction technology of engineering vehicles has not been paid much attention by various countries.

Engineering vehicles mainly use hydraulically driven actuators to move, and hydraulic cylinders need to be extended and recovered frequently. The hydraulic energy is finally lost in the form of heat energy during the conversion process with other energies, which greatly reduces the fuel economy of engineering vehicles. In response to this problem, some people have proposed a scheme to convert the hydraulic energy of engineering vehicles into electrical energy for recovery, but in the process of recovery and utilization, the hydraulic energy needs to be converted into electrical energy, and then the electrical energy is converted into hydraulic energy. The loss in the conversion process of the form is huge, so the fuel economy improvement is not obvious. Others have proposed the use of hydraulic accumulators to recover the hydraulic energy of engineering vehicles. However, due to the complex and changeable operating conditions of engineering vehicles, the hydraulic energy recovery system with fixed capacity and pressure has not been able to fully recover hydraulic energy.

Therefore, it is necessary to improve the hydraulic energy recovery system and its working method on the premise of ensuring the stable operation of engineering vehicles, so as to improve the energy recovery and utilization rate as much as possible, and realize the energy saving and emission reduction of engineering vehicles.

Contents of the invention

The purpose of the present invention is to realize the full recovery of the hydraulic energy of the engineering vehicle, and propose a hydraulic energy recovery system with adjustable pressure and capacity and its working method.

The invention provides a hydraulic energy recovery and storage system with adjustable pressure and capacity, including: oil cylinder, variable hydraulic pump, hydraulic switch network, hydraulic cylinder, hydraulic accumulator, air pressure accumulator, three-position three-way valve and two Position three-way valve; wherein, the variable hydraulic pump is connected to the oil cylinder, and the output end is connected to the hydraulic switch network; the hydraulic switch network is connected to the hydraulic accumulator; the hydraulic accumulator has a lower hydraulic chamber and an upper compressed air chamber; the compression of the hydraulic accumulator The air chamber communicates with the air pressure accumulator through the three-position three-way valve; the hydraulic cylinder is connected with the hydraulic switch network.

Among them, the hydraulic switch network is composed of switching valves 1 to 9, a one-way valve, and a two-position three-way valve: one end of the switching valve 1 is connected to the variable hydraulic pump, the other end is connected to one end of the one-way valve, and the other end of the one-way valve is simultaneously Connect on-off valves five to seven; on-off valve five and on-off valve six are connected in series, on-off valve eight and on-off valve nine are connected in series, and the two branches are connected in series and then connected in parallel. On the middle pipeline; one end of the switch valve two is connected between the switch valve one and the one-way valve, and the other end is connected to the two-position three-way valve and then connected to the hydraulic chamber of the hydraulic accumulator; one end of the switch valve four is connected to the switch valve at the same time 3. On-off valves seven to nine are connected to the hydraulic chamber of the hydraulic accumulator at the other end; wherein, the one-way valve and on-off valve four are connected to different ends of on-off valve seven.

Wherein, the air pressure accumulator is an air tank.

Preferably, another one-way valve is added on the pipeline before the two-position three-way valve is respectively connected with the switch valve four and the hydraulic chamber of the hydraulic accumulator.

As a preference, a pressure reducing valve 1 is set on the pipeline between the variable hydraulic pump and the switching valve 1, and the pressure reducing valve 1 communicates with the oil cylinder. By controlling the pressure reducing valve 1, the hydraulic oil in the hydraulic switch network can be discharged. Into the oil cylinder, so as to realize the adjustment of the oil pressure in the hydraulic switch network.

As a preference, the lower hydraulic chamber of the hydraulic accumulator is connected with a pressure reducing valve 2, and the pressure reducing valve 2 communicates with the oil cylinder. By controlling the pressure reducing valve 2, the hydraulic oil in the hydraulic chamber of the hydraulic accumulator can be discharged into the in the cylinder.

As preferably, an air pressure relief valve is arranged on the pipeline between the air pressure accumulator and the three-position three-way valve, and the air pressure pressure relief valve communicates with the atmosphere. By controlling the air pressure pressure relief valve, the air pressure pressure relief valve in the air pressure accumulator can be The compressed air is discharged into the atmosphere, so as to realize the pressure regulation of the compressed air chamber of the pneumatic accumulator or/and hydraulic accumulator.

Preferably, the hydraulic energy recovery and storage system further includes a hydraulic accumulator booster. The booster device is a hydraulic pump, which is connected between the switch valve two and the two-position three-way valve, and its hydraulic oil input end is connected to the right position of the two-position three-way valve. The hydraulic pump can store energy in the hydraulic accumulator. When the pressure of the hydraulic oil stored in the hydraulic accumulator is low, the two-position three-way valve is controlled to be in the right position, and the hydraulic oil is used to drive the hydraulic cylinder after being pressurized by the hydraulic pump. The power input end of the hydraulic pump is connected with the output shaft of the motor/generator of the engineering vehicle through a clutch.

Preferably, the hydraulic energy recovery and storage system further includes an air tank pressurization device. The air tank pressurizing device is a high-pressure air pump. The gas input port of the high-pressure air pump is connected with the atmosphere, and the output port is connected with the air tank. The high-pressure air pump can perform pressurization operation on the air tank to make the pressure of the air tank reach the desired working pressure. The high-pressure air pump is driven by the motor/generator of the engineering vehicle.

The present invention also provides the working method of the hydraulic energy recovery and storage system:

The engineering vehicle engine is controlled to run at the optimum operating point.

The engineering vehicle engine drives the variable hydraulic pump through the clutch, and drives the variable hydraulic pump to provide high-pressure hydraulic oil to the hydraulic energy recovery and storage system. The mechanical energy output by the engineering vehicle engine is first converted into the hydraulic energy of the high-pressure hydraulic oil; when the output power of the engineering vehicle engine When the energy required by the hydraulic cylinder to lift the load is exceeded, a part of the hydraulic energy will be stored in the hydraulic energy recovery and storage system. At this time, the three-position three-way valve is in the neutral position and is closed, and the hydraulic energy is first stored in the In the hydraulic accumulator, when the energy storage pressure of the hydraulic accumulator exceeds its own maximum operating pressure, by controlling the three-position three-way valve to make it in the left position, the compressed air chamber of the hydraulic accumulator and the air pressure energy storage The accumulator is connected to store part of the hydraulic energy in the form of pneumatic energy in the pneumatic accumulator.

For the hydraulic energy in the hydraulic cylinder: when the load of the hydraulic cylinder decreases, the three-position three-way valve is in the neutral position and is in a closed state. The high-pressure hydraulic oil in the hydraulic cylinder will first be stored in the hydraulic accumulator. When the hydraulic accumulator When the energy storage pressure of the accumulator exceeds its own maximum operating pressure, by controlling the three-position three-way valve to make it in the left position, the compressed air chamber of the hydraulic accumulator communicates with the air pressure accumulator, and the hydraulic accumulator Part of the high-pressure gas is charged into the pneumatic accumulator through the three-position three-way valve.

When it is necessary to release energy, first control the three-position three-way valve in the neutral position, the compressed air chamber of the hydraulic accumulator is disconnected from the pneumatic accumulator, the hydraulic accumulator releases energy first, and when the pressure drops to a certain set threshold, Control the three-position three-way valve to be in the left position, and the compressed air chamber of the hydraulic accumulator is boosted by the air pressure accumulator to further release the energy stored in the air pressure accumulator. When the air pressure in the air pressure accumulator drops to When the ultimate pressure is set, the valves of all hydraulic energy storage and recovery systems and gas tanks are controlled to be closed, and the release of energy from the hydraulic energy recovery and storage system is stopped; the cycle is like this.

When the output energy of the engineering vehicle engine is less than the energy required to lift the load, the required energy can be jointly provided by the engineering vehicle engine and the hydraulic energy recovery and storage system, which not only improves fuel economy, but also greatly enhances the belt load of the system. load capacity.

The present invention uses a hydraulic accumulator and an air tank to recover hydraulic energy, and adjusts the pressure and capacity double parameters, which can ensure the control of the recovery pressure, ensure the recovery speed of the hydraulic rod, and recover and utilize the hydraulic energy to a greater extent. At the same time, the recovery capacity can also have a variety of auxiliary adjustment methods to ensure that the energy of the system is fully recovered. In the present invention, a matrix type hydraulic switch network is creatively adopted to realize the configuration of oil circuits in all directions.

A hydraulic energy recovery and storage system with adjustable pressure and capacity and its working method proposed by the present invention can improve the recovery and utilization rate of energy as much as possible under the premise of ensuring the stable operation of the vehicle, improve the fuel economy of the vehicle, and realize Energy saving and emission reduction of engineering vehicles. And under the limit of the rated output power, the vehicle can be equipped with an engine with a smaller capacity, or under the same installed capacity, it has a stronger load carrying capacity, which does not sacrifice vehicle performance, but also reduces the cost of construction and use.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of the present invention.

In the figure: oil cylinder 1, variable hydraulic pump 2, pressure reducing valve 1 3, hydraulic pump 4, check valve 1 5, hydraulic cylinder 6, hydraulic accumulator (inflatable hydraulic tank) 7, air pressure pressure reducing valve 8, air pressure Accumulator (air tank) 9, air pump 10, on-off valve 11-19, three-position three-way valve 20, two-position three-way valve 21, pressure reducing valve two 22, muffler 23, one-way valve two 24.

Detailed ways

For the technical means that the present invention realizes, purpose of the invention and technical effect are easy to understand, below in conjunction with accompanying drawing 1 the present invention is described in further detail:

In Fig. 1, the hydraulic energy recovery and storage system with adjustable pressure and capacity of the present invention includes: oil cylinder 1, variable hydraulic pump 2, hydraulic switch network, hydraulic cylinder 6, hydraulic accumulator 7, air pressure accumulator 9, three One-position three-way valve 20 and two-position three-way valve 21. Wherein, the variable hydraulic pump 2 is connected to the oil cylinder 1, and the output end is connected to the hydraulic switch network. The hydraulic switch network communicates with the hydraulic accumulator 7 . The hydraulic accumulator 7 is an air-filled hydraulic tank with a lower hydraulic chamber and an upper compressed air chamber. The compressed air chamber of the hydraulic accumulator 7 communicates with the pneumatic accumulator 9 through a three-position three-way valve 20 . The hydraulic cylinder 6 is connected to the hydraulic switch network.

Among them, the hydraulic switch network is composed of switching valves 1 to 9 11-19, a one-way valve 5, and a two-position three-way valve 21. Among them, one end of switch valve one 11 is connected with variable hydraulic pump 2, the other end is connected with one end of one-way valve one 5, and the other end of one-way valve 5 is connected with switch valves five to seven 15-17 at the same time, and switch valves five to nine 15-19 form a bridging pipeline (that is, on-off valve five 15 is connected in series with on-off valve six 16, on-off valve eight 18 is connected in series with on-off valve nine 19, and the two branches are connected in series and then connected in parallel, and then the two ends of on-off valve seven 17 respectively connected to the intermediate pipelines of the two serial branches); one end of switch valve two 12 is connected between switch valve one 11 and one-way valve one 5, and the other end is connected with two-position three-way valve 21 and hydraulic accumulator 7 The hydraulic chamber connection of switch valve four 14 is connected with switch valve three 13 and switch valve seven to nine 17-19 at the same time, and the other end is connected with the hydraulic chamber of hydraulic accumulator 7; wherein, one-way valve one 5 and switch valve four 14 is connected to the different ends of switching valve seven 17. Wherein, another one-way valve can be added between the two-position three-way valve 21 and the switching valve four 14 and the hydraulic chamber of the hydraulic accumulator 7 respectively.

A hydraulic pump 4 can be added to the hydraulic energy recovery and storage system with adjustable pressure and capacity of the present invention. The hydraulic pump 4 is connected between the switch valve 2 12 and the two-position three-way valve 21, and its hydraulic oil input end is connected to the right side of the two-position three-way valve 21. The hydraulic pump 4 is connected to the output shaft of the motor/generator (not shown in the figure) of the engineering vehicle through a clutch, and the hydraulic pump 4 can boost the hydraulic oil stored in the hydraulic accumulator. When the hydraulic oil pressure in the energy device 7 is low, the two-position three-way valve 21 is controlled to be in the right position, and the hydraulic oil is used to drive the hydraulic cylinder 6 after being pressurized by the hydraulic pump 4 .

In addition, a pressure reducing valve 3 can be set on the pipeline between the variable hydraulic pump 2 and the switch valve 11. The pressure reducing valve 3 communicates with the oil cylinder 1. By controlling the pressure reducing valve 3, the hydraulic switch can be The high-pressure hydraulic oil in the network is discharged into the oil cylinder 1, so as to realize the adjustment of the oil pressure in the hydraulic switch network, as one of the auxiliary means for pressure and volume adjustment.

In addition, the lower hydraulic chamber of the hydraulic accumulator 7 is connected with a pressure reducing valve 22, which communicates with the oil cylinder 1. By controlling the pressure reducing valve 22, the pressure in the hydraulic chamber of the hydraulic accumulator 7 can be The hydraulic oil is discharged into the oil cylinder 1, which becomes one of the auxiliary means for adjusting the pressure and volume.

In addition, an air pressure relief valve 8 is set on the pipeline between the air pressure accumulator 9 and the three-position three-way valve 20. The air pressure pressure relief valve 8 communicates with the atmosphere. By controlling the air pressure pressure relief valve 8, the air pressure can be reduced. The compressed air in the accumulator 9 is discharged into the atmosphere, so as to realize the pressure adjustment of the compressed air chamber of the pneumatic accumulator 9 and/or hydraulic accumulator 7 . The air pressure accumulator 9 is an air tank.

As one of the auxiliary means for pressure and volume adjustment, a high-pressure air pump 10 can be added to the air pressure accumulator 9 . The gas input port of the high-pressure air pump 10 is connected to the atmosphere, and the output port is connected to the gas tank. The high-pressure gas pump 10 can perform a pressurization operation on the gas tank to make the pressure of the gas tank reach the desired working pressure. The high-pressure air pump 10 is driven by an electric motor/generator (not shown in the figure) of the engineering vehicle.

The working principle of the hydraulic energy recovery and storage system with adjustable pressure and capacity of the present invention will be introduced below.

The hydraulic cavity of the hydraulic cylinder 6 is connected in parallel with the aforementioned bridging pipeline. The cylinder piston of the hydraulic cylinder 6 is connected to the driven mechanism, such as the lifting table of the elevator, the boom or stick of the excavator, etc., and the cylinder piston of the hydraulic cylinder 6 is driven by hydraulic oil to lift the load when it rises. The gravitational potential energy in the load descending process is stored in the hydraulic accumulator 7 or/and the pneumatic accumulator 9 in the form of hydraulic energy.

After the hydraulic oil passes through the one-way valve 5, it needs to pass through the hydraulic valve group for oil circuit configuration. On-off valves one to nine 11-19, two-position three-way valve 21 and three-position three-way valve 20 form a hydraulic switch network and a pneumatic switch circuit. The switching states of different valves realize different hydraulic/pneumatic energy flows. The logic switch state can realize the flexible configuration of oil circuit/air circuit. According to Figure 1, the main operating conditions are analyzed as follows:

Working condition 1: variable hydraulic pump 2 outputs hydraulic oil, controls on-off valve one 11, on-off valve six 16, on-off valve eight 18, on-off valve three 13 to the right, and the rest of the on-off valves are closed, the rodless hydraulic chamber of hydraulic cylinder 6 The interior is filled with oil, and the hydraulic cylinder 6 is extended, which can realize operations such as lifting of engineering vehicles.

Working condition 2: control on-off valve two 12 right position, two-position three-way valve 21 left or right position (in the right position, connect hydraulic pump 4 to pressurize the hydraulic oil in the accumulator and then output), on-off valve six 16, on-off valve eight 18, on-off valve three 13 right positions, all the other on-off valves are closed, the rodless hydraulic cavity of hydraulic cylinder 6 is filled with oil, and hydraulic cylinder 6 is elongated.

Working condition 3: On-off valve one 11 is in the right position, variable hydraulic pump 2 outputs hydraulic oil, on-off valve five 15, on-off valve four 14, on-off valve nine 19 are on the right, the rest of the on-off valves are closed, hydraulic cylinder 6 has no rod cavity Oil, the hydraulic cylinder 6 is shortened, the hydraulic accumulator 7 stores energy, and the potential energy in the process of the piston of the hydraulic cylinder 6 descending is recovered and stored in the form of hydraulic energy.

Working condition 4: All switch valves are closed, and the three-position three-way valve 20 is in the left or right position to adjust the back pressure of the hydraulic accumulator 7 (that is, the air pressure in the upper compressed air chamber of the hydraulic accumulator 7), so as to realize the hydraulic energy The pressure and capacity of the recovery system can be adjusted. When the three-position three-way valve 20 is in the left position, the pneumatic accumulator 9 communicates with the compressed air cavity of the hydraulic accumulator 7, and the back pressure of the hydraulic accumulator can be adjusted: if the compressed air cavity of the hydraulic accumulator 7 The pressure of the pressure is lower than the pressure of the pneumatic accumulator 9, the energy stored in the pneumatic accumulator 9 will return to the hydraulic accumulator 7, and the back pressure of the hydraulic accumulator 7 will rise; if the compression of the hydraulic accumulator 7 The pressure of the air cavity is higher than the pressure of the air accumulator 9, the air accumulator 9 can be charged, and part of the recovered energy is stored in the air accumulator 9. When the three-position three-way valve 20 is in the neutral position, the compressed air cavity of the hydraulic accumulator 7 is disconnected from the air pressure accumulator 9 . When the three-position three-way valve 20 is in the right position, the air in the compressed air chamber of the hydraulic accumulator 7 can be discharged through the muffler 23, so as to realize the decompression operation of the compressed air chamber of the hydraulic accumulator 7, which is also the pressure on the hydraulic accumulator. 7 An adjustment method for pressure and capacity.

Working condition 5: On-off valve one 11 is on the right, on-off valve seven 17, on-off valve four 14 are on the right, the rest of the on-off valves are all closed, and the hydraulic energy generated by the vehicle engine (not shown in the figure) driving the variable hydraulic pump 2 can be directly Stored in the hydraulic accumulator 7.

In order to better recover and utilize hydraulic energy and improve the efficiency of the entire system, the above working conditions can be combined or exist independently.

The following is a description of the working method of the pressure and capacity adjustable hydraulic energy recovery and storage system of the present invention.

According to Figure 1, during the operation of the engineering vehicle, the vehicle engine (not shown in the figure) is controlled to run at the desired optimal operating point with fuel saving or emission reduction as the control index, and the vehicle engine passes through the clutch (not shown in the figure). output) to drive the variable hydraulic pump 2, and drive the variable hydraulic pump 2 to provide high-pressure hydraulic oil to the hydraulic energy recovery and storage system, and the mechanical energy output by the vehicle engine is first converted into hydraulic energy of the high-pressure hydraulic oil. When the engine output exceeds the energy required to lift the load, part of the hydraulic energy will be stored in the hydraulic energy recovery and storage system. At this time, the three-position three-way valve 20 is in the neutral position and is in a closed state. The hydraulic energy is firstly stored in the hydraulic accumulator 7. When the accumulator pressure of the hydraulic accumulator 7 exceeds its maximum operating pressure, the three-position Position the three-way valve 20 so that it is in the left position, the compressed air cavity of the hydraulic accumulator 7 communicates with the air pressure accumulator 9, and part of the hydraulic energy is stored in the air pressure accumulator 9 in the form of air pressure, thereby increasing The energy storage capacity ensures maximum recovery of energy.

The hydraulic energy in the hydraulic cylinder 6 can also be stored in the same way: during the descent of the hydraulic cylinder 6, the three-position three-way valve 20 is in the neutral position and is in a closed state, and the high-pressure hydraulic oil in the rodless cavity of the hydraulic cylinder will be stored first. In the hydraulic accumulator 7. When the energy storage pressure of the hydraulic accumulator 7 exceeds its own maximum operating pressure, the compressed air chamber of the hydraulic accumulator 7 communicates with the air pressure accumulator 9 by controlling the three-position three-way valve 20 so that it is in the left position , the high-pressure gas in the hydraulic accumulator 7 is partially charged into the gas tank through the three-position three-way valve 20 .

When the output energy of the vehicle engine is less than the energy required to lift the load, the required energy is jointly provided by the vehicle engine and the hydraulic energy recovery and storage system. At this time, the three-position three-way valve 20 is controlled to be in the neutral position, the compressed air chamber of the hydraulic accumulator 7 is disconnected from the air pressure accumulator 9, and the hydraulic accumulator 7 first releases energy; when the pressure drops to a certain set threshold, Control the three-position three-way valve 20 to be in the left position, and the compressed air chamber of the hydraulic accumulator 7 is boosted by the air pressure accumulator 9 to further release the energy stored in the air pressure accumulator 9. When the air pressure accumulator 9 When the air pressure drops to the set limit pressure, all hydraulic and pneumatic valves are controlled to be closed, and the release of energy from the hydraulic energy recovery and storage system is stopped. Such circulation, recovery and utilization of hydraulic energy improves the fuel economy of the entire system.

The oil cylinders involved in the description of the present invention all refer to the oil cylinder 1 .

The storage methods of hydraulic energy in the present invention are flexible and diverse, and can be directly stored as hydraulic energy, or further stored as pneumatic energy. The scheme design realizes the adjustable storage pressure and volume of hydraulic energy, and increases the efficiency of energy recovery.

The present invention is not limited to the above description of the embodiments, those skilled in the art according to the content disclosed by the present invention, do not need to go through the improvement and modification carried out by creative work on the basis of the present invention, such as hydraulic tanks, air pressure tanks, pressurization devices and venting devices. The selection and setting of the pressure device, etc., should all be within the protection scope of the present invention.

Claims (9)

1. a kind of pressure and the adjustable hydraulic energy recovery of capacity and stocking system, it is characterised in that including：Oil cylinder (1), variable liquid Press pump (2), hydraulic selector network, hydraulic cylinder (6), hydraulic accumulator (7), gas-loaded accumulator (9), three-position three-way valve (20) and two Position three-way valve (21)；Wherein, the hydraulic oil input of the volume adjustable hydraulic pump (2) connects the oil cylinder (1), output end connection institute State hydraulic selector network；The hydraulic selector network connects with the hydraulic accumulator (7)；The hydraulic accumulator (7) has Lower hydraulic chamber and top compression air chamber；The compressed air cell of the hydraulic accumulator (7) passes through the three-position three-way valve (20) connected with the gas-loaded accumulator (9)；

The hydraulic selector network is made up of (21) switch valve one to nine (11-19), check valve one (5), two position three-way valve：It is described One end of switch valve one (11) is connected with the volume adjustable hydraulic pump (2), and the other end is connected with one end of the check valve one (5), The other end of the check valve one (5) connects the switch valve five to seven (15-17) simultaneously；(the 15- of switch valve five to nine 19) bridge line is formed, i.e., described switch valve five (15) concatenates with the switch valve six (16), the switch valve eight (18) and institute State switch valve nine (19) concatenation, the two concatenations branch road again and connects, the both ends of the switch valve seven (17) be connected to this two In the intermediate duct for concatenating branch road；The hydraulic cavities of the hydraulic cylinder (6) are attempted by the bridge line；The switch valve two (12) one end is connected between the switch valve one (11) and the check valve one (5), and the other end connects the two-position three way Hydraulic cavities of the valve (21) afterwards with the hydraulic accumulator (7) are connected；Opened connect simultaneously described in one end of the switch valve four (14) Valve three (13), the switch valve seven to nine (17-19) are closed, the other end is connected with the hydraulic cavities of the hydraulic accumulator (7)；Its In, the check valve one (5) and the switch valve four (14) are connected to the different ends of the switch valve seven (17).

2. a kind of pressure according to claim 1 and the adjustable hydraulic energy recovery of capacity and stocking system, it is characterised in that Wherein, the gas-loaded accumulator (9) is gas tank.

3. a kind of pressure according to claim 1 and the adjustable hydraulic energy recovery of capacity and stocking system, it is characterised in that Pipe before the two position three-way valve (21) is connected with the hydraulic cavities of the switch valve four (14) and the hydraulic accumulator (7) Lu Shang, set up another check valve.

4. a kind of pressure according to claim 1 and the adjustable hydraulic energy recovery of capacity and stocking system, it is characterised in that One pressure-reducing valve one (3), the decompression are set on the pipeline between the volume adjustable hydraulic pump (2) and the switch valve one (11) Valve one (3) connects with the oil cylinder (1), can be by the hydraulic oil in the hydraulic selector network by controlling the pressure-reducing valve one (3) It is discharged into the oil cylinder (1), so as to realize the regulation to oil pressure in hydraulic selector network.

5. a kind of pressure according to claim 1 and the adjustable hydraulic energy recovery of capacity and stocking system, it is characterised in that The lower hydraulic chamber of the hydraulic accumulator (7) connects a pressure-reducing valve two (22), the pressure-reducing valve two (22) and the oil cylinder (1) connect, by controlling the pressure-reducing valve two (22), the hydraulic oil in the hydraulic cavities of the hydraulic accumulator (7) can be discharged into institute State in oil cylinder (1).

6. a kind of pressure according to claim 1 and the adjustable hydraulic energy recovery of capacity and stocking system, it is characterised in that One air pressure reducing device (8) is set on the pipeline between the gas-loaded accumulator (9) and the three-position three-way valve (20), it is described Air pressure reducing device (8) and atmosphere, can be by the compression in the gas-loaded accumulator (9) by controlling the air pressure reducing device (8) Air is discharged into air, so as to realize to the compressed air cell of the gas-loaded accumulator (9) or/and the hydraulic accumulator (7) Pressure is adjusted.

7. a kind of pressure according to claim 1 and the adjustable hydraulic energy recovery of capacity and stocking system, it is characterised in that Hydraulic energy recovery and stocking system also include hydraulic accumulator supercharging device, and the supercharging device is hydraulic pump (4), the liquid Press pump (4) is connected between the switch valve two (12) and the two position three-way valve (21), and the hydraulic oil of the hydraulic pump (4) is defeated Enter the right position that end connects the two position three-way valve (21), the hydraulic pump (4) can be in the hydraulic cavities of the hydraulic accumulator (7) The hydraulic oil of storage carries out boost operations, when the hydraulic oil in the hydraulic cavities for being stored in the hydraulic accumulator (7) pressure compared with When low, the two position three-way valve (21) is controlled to be in right position, hydraulic oil is described for driving after the hydraulic pump (4) pressurization Hydraulic cylinder (6) acts.

8. a kind of pressure according to claim 2 and the adjustable hydraulic energy recovery of capacity and stocking system, the hydraulic energy Recovery and stocking system also include gas tank pressue device, and the gas tank pressue device is a high-pressure pump (10), the high pressure gas The gas input port and atmosphere of pump (10), gas delivery port are connected with gas tank.

9. a kind of a kind of adjustable hydraulic energy recovery of pressure and capacity based on described in claim any one of 1-8 and stocking system Method of work, hydraulic energy recovery and stocking system are applied to engineering truck, it is characterised in that：

Engineering vehicle engine control is operated in into optimal working point；

Engineering vehicle engine drives the volume adjustable hydraulic pump (2) by clutch, drives the volume adjustable hydraulic pump (2) to described Hydraulic energy reclaims and stocking system provides high pressure liquid force feed, and the mechanical energy of engineering vehicle engine output is converted to the high pressure first The hydraulic energy of hydraulic oil；

When the power output of engineering vehicle engine is beyond the required energy of the hydraulic cylinder (6) lifting load, a part Hydraulic energy is stored in the hydraulic energy recovery and stocking system, and now, the three-position three-way valve (20) is in middle position, in pass Closed state, hydraulic energy are stored in the hydraulic accumulator (7) first, when the energy-storage pressure of the hydraulic accumulator (7) surpasses When crossing the maximum operating pressure of its own, by controlling the three-position three-way valve (20) to be in left position, the hydraulic accumulator (7) Compressed air cell connected with the gas-loaded accumulator (9), section hydraulic can be stored in the air pressure in a manner of air pressure In accumulator (9)；

For the hydraulic energy in hydraulic cylinder (6)：During hydraulic cylinder (6) load declines, during three-position three-way valve (20) is in Position, in closed mode, the high pressure liquid force feed in hydraulic cylinder (6) can be firstly stored in hydraulic accumulator (7), work as hydraulic accumulator (7) when energy-storage pressure exceedes the maximum operating pressure of its own, by controlling three-position three-way valve (20), left position is at, The compressed air cell of hydraulic accumulator (7) connects with gas-loaded accumulator (9), and the partial high pressure gas in hydraulic accumulator (7) leads to Three-position three-way valve (20) is crossed to be filled into gas-loaded accumulator (9)；

When the power output of engineering vehicle engine is less than the required energy of the hydraulic cylinder (6) lifting load, this is required Energy is provided jointly by engineering vehicle engine and hydraulic energy recovery and stocking system, now, controls the 3-position-3-way Valve (20) is in middle position, and compressed air cell and the gas-loaded accumulator (9) of the hydraulic accumulator (7) disconnect, the hydraulic pressure Accumulator (7) releases energy first, when the pressure of the compressed air cell of the hydraulic accumulator (7) drops to certain given threshold When, control the three-position three-way valve (20) to be in left position, the pressure by the gas-loaded accumulator (9) to the hydraulic accumulator (7) Contracting air chamber is boosted, and the energy stored in gas-loaded accumulator is further discharged, when under the air pressure in gas-loaded accumulator When dropping to setting limit pressure, whole hydraulic pressure and air pressure valve are closed in control, are stopped from hydraulic energy recovery and stocking system Release energy；By described above, circulation work.