Energy recovery system and method for hydro-pneumatic suspension

Abstract

This invention discloses an energy recovery system and method for an oil-gas suspension. The energy recovery system includes a suspension actuator, a dual-piston assembly, a piezoelectric stack, and a disc spring assembly. The first piston assembly divides the actuator into a rodless chamber and a rod chamber, with a second piston assembly inserted upside down into the blind hole of its piston rod. The piezoelectric stack is divided into two groups: one group is located on the bottom surface of the rod chamber, and the other group is placed between the two piston assemblies. The disc spring assembly contains five disc springs; the first disc spring connects to the upper and lower end faces of the blind hole, and the rest are placed on both sides of the two piston rods and connected by a pad. The system adopts a dual-path energy recovery: large-scale vibration energy recovery is achieved through a hydraulic motor-coupling-permanent magnet generator-rectifier-battery; small-scale energy recovery is achieved through disc springs-piezoelectric stack-diode-supercapacitor assembly. It features high energy utilization, compact structure, and long service life, and can store vibration energy in the battery and supercapacitor respectively.

Description

Technical Field

[0001] This invention relates to the field of hydropneumatic suspension actuators, and more particularly to an energy recovery system and method for hydropneumatic suspensions. Background Technology

[0002] Hydropneumatic suspension systems, due to their nonlinear stiffness, wide damping adjustment range, and high load-bearing capacity, are widely used in mining dump trucks, armored vehicles, and heavy engineering equipment. However, when operating on complex road surfaces (such as mining areas and off-road terrain), frequent vibrations and impacts cause a significant amount of mechanical energy to be converted into the internal energy of the hydraulic oil, leading to problems such as increased oil temperature, seal aging, and shortened lifespan. Simultaneously, this energy is dissipated as heat, resulting in energy waste. Therefore, there is an urgent need to design an energy recovery system for hydropneumatic suspension systems to address these issues.

[0003] Chinese patent application CN 120156243A discloses a multi-mode energy-feeding suspension actuator and its control method, which integrates piezoelectric materials and a linear motor within the suspension. Hydraulic oil compression deforms the piezoelectric material, and the piston rod drives the linear motor in reciprocating motion, generating electrical energy from the piezoelectric material and the permanent magnet, respectively. However, integrating the linear motor into the suspension inevitably presents mechanical coupling problems due to motor jamming, as it shares a piston rod with the air spring. Furthermore, this actuator only generates energy through piezoelectric material deformation when the piston rod is compressed; when the piston rod is stretched, the piezoelectric material does not contribute to energy feeding. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an energy recovery system and method for hydropneumatic suspensions. On one hand, a piston compresses a disc spring, further compressing a piezoelectric stack to generate electrical energy through deformation, forming a piezoelectric stage recovery. This electrical energy is stored in a supercapacitor to power a high-speed switching valve. On the other hand, hydraulic oil flows into a hydraulic motor, driving a permanent magnet generator to generate electrical energy, forming a hydraulic stage recovery. This electrical energy is stored in a battery to power a hydraulic pump. This invention achieves graded recovery of vibration energy from hydropneumatic suspensions, offering advantages such as high energy utilization, long service life, and simple structure.

[0005] To achieve the above objectives, the present invention provides an energy recovery system for an oil-gas suspension, comprising a suspension actuator, several piston assemblies, several disc springs, several pads, several piezoelectric stacks, diodes, several supercapacitors, an electronic control unit, a hydraulic motor, several couplings, a permanent magnet generator, a rectifier, a battery, a motor, a hydraulic pump, and a high-speed switching valve assembly.

[0006] The first piston assembly is placed inside the suspension actuator cylinder. The upper chamber of the first piston assembly is the rodless chamber of the suspension actuator cylinder, and the lower chamber is the rod chamber of the suspension actuator cylinder.

[0007] The first piston assembly consists of the first piston and the first piston rod.

[0008] The first piston rod has a blind hole at its center, and the top of the first disc spring coincides with the top surface of the blind hole of the first piston rod.

[0009] Preferably, the second piston rod is inserted backward into the blind hole of the first piston rod, and the top surface of the second piston rod coincides with the bottom end of the first disc spring.

[0010] The second and fourth disc springs are placed on the left and right sides of the first piston rod, and the top ends of the second and fourth disc springs coincide with the lower end face of the first piston, and are placed in the rod chamber of the suspension actuator.

[0011] Preferably, the first pad and the third pad are provided below the second disc spring and the fourth disc spring.

[0012] Preferably, the first piezoelectric stack and the third piezoelectric stack are disposed below the first pad and the third pad, and the first piezoelectric stack and the third piezoelectric stack are located at the bottom of the rod cavity of the suspension actuator.

[0013] Preferably, the third disc spring and the fifth disc spring are placed on the left and right sides of the second piston rod, and the bottom ends of the third disc spring and the fifth disc spring coincide with the upper end surface of the second piston.

[0014] Preferably, the second pad and the fourth pad are provided above the third disc spring and the fifth disc spring.

[0015] Preferably, the second piezoelectric stack and the fourth piezoelectric stack are provided above the second pad and the fourth pad, and the second piezoelectric stack and the fourth piezoelectric stack coincide with the lower end face of the first piston rod.

[0016] Preferably, the energy generated by the plurality of piezoelectric stacks is unidirectionally stored in the supercapacitor group via the diode, and the electronic control unit determines whether it is necessary to supply power to the high-speed switching valve group.

[0017] The hydraulic motor is connected to the rodless chamber of the suspension actuator and is connected to the permanent magnet generator through a first coupling.

[0018] Preferably, the energy generated by the permanent magnet generator is alternating current, which is converted into direct current by the rectifier and stored in the battery.

[0019] On the other hand, the present invention also provides an energy recovery method for hydropneumatic suspension, comprising the following steps:

[0020] The first energy recovery step: When the piston assembly reciprocates, the hydraulic oil in the rodless chamber of the suspension actuator flows into the hydraulic motor; the combined pressure and flow of the hydraulic oil drives the motor rotor to rotate, and the motor output shaft drives the permanent magnet generator rotor to rotate at high speed through the first coupling, and the stator winding cuts the magnetic field lines to generate three-phase alternating current. This alternating current is converted into direct current by a rectifier and directly stored in the battery to power the motor.

[0021] Second-scale energy recovery step: Based on the hydraulic stage, the system simultaneously deploys a piezoelectric stack:

[0022] (1) Compression stroke: The second piston assembly moves upward, and the second and fourth piezoelectric stacks are compressed step by step by the first, third and fifth disc springs to generate electrical energy;

[0023] (2) Extension stroke: The second piston assembly moves downward, and the first and third piezoelectric stacks built into the rod cavity of the suspension actuator are compressed in the opposite direction by the second and fourth disc springs to generate electrical energy.

[0024] The pulsed electrical energy output from the two sets of piezoelectric stacks is rectified in parallel and then fed into the supercapacitor group. The electronic control unit monitors the enable signal of the high-speed switching valve group. When the electronic control unit detects the rising edge of the enable signal of a certain high-speed switching valve, it controls the opening of the MOS transistor located on the electronic control unit, and the electrical energy is transferred from the supercapacitor group to the coil of the high-speed switching valve to open it.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] (1) Since the permanent magnet generator is separated from the oil-gas suspension, the coil windings and permanent magnets of the generator can be prevented from being contaminated by oil. At the same time, the permanent magnet generator and the suspension do not share a piston assembly, so the leveling function of the oil-gas suspension will not be affected by mechanical coupling failure caused by generator jamming.

[0027] (2) Since the piezoelectric stack is both built into the suspension and placed between the external piston assembly, the piezoelectric stack can generate energy regardless of whether the suspension is in a compressed or stretched state, which significantly improves the vibration energy utilization rate, reduces system energy consumption, and realizes the self-supply of energy for the oil and gas suspension. Attached Figure Description

[0028] Figure 1 A schematic diagram of a dual-scale energy recovery system for hydropneumatic suspension provided in an embodiment of the present invention;

[0029] Figure 2This is a schematic diagram of the first piston assembly structure provided in an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the second piston assembly structure provided in an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the permanent magnet generator structure provided in an embodiment of the present invention;

[0032] The components include: 1. Suspension actuator; 2. First piston assembly; 2.1. First piston; 2.2. First piston rod; 2.3. Upper end face of blind hole; 2.4. Lower end face of first piston; 2.5. Lower end face of first piston rod; 3. First disc spring; 4. Second piston assembly; 4.1. Second piston rod; 4.2. Second piston; 4.3. Upper end face of second piston rod; 4.4. Upper end face of second piston; 5. Second disc spring; 6. First pad; 7. First piezoelectric stack; 8. Second piezoelectric stack; 9. Second pad; 10. Third disc spring; 11. 12. Fourth disc spring; 13. Third pad; 14. Third piezoelectric stack; 15. Fourth pad; 16. Fifth disc spring; 17. Diode; 18. Supercapacitor bank; 19. Electronic control unit; 20. High-speed switching valve group; 21. Accumulator group; 22. Hydraulic motor; 23. First coupling; 24. Permanent magnet generator; 24.1. Rotor; 24.2. Stator; 24.3. Copper wire winding; 25. Rectifier; 26. Battery; 27. Motor; 28. Second coupling; 29. ​​Hydraulic pump; 30. Oil tank. Detailed Implementation

[0033] The system and method of the present invention will be further described below with reference to the accompanying drawings and embodiments, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The accompanying drawings form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the invention, but are not intended to limit the scope of the invention.

[0034] The following is a detailed description of an energy recovery system for an oil-gas suspension according to an embodiment of the present invention, with reference to the accompanying drawings.

[0035] Please see Figure 1 , Figure 2According to an embodiment of the present invention, an energy recovery system for a hydropneumatic suspension includes a suspension actuator 1, a first piston assembly 2, a first disc spring 3, a second piston assembly 4, a second disc spring 5, a first pad 6, a first piezoelectric stack 7, a second piezoelectric stack 8, a second pad 9, a third disc spring 10, a fourth disc spring 11, a third pad 12, a third piezoelectric stack 13, a fourth piezoelectric stack 14, a fourth pad 15, a fifth disc spring 16, a diode 17, a supercapacitor group 18, an electronic control unit 19, a high-speed switching valve group 20, an accumulator group 21, a hydraulic motor 22, a first coupling 23, a permanent magnet generator 24, a rectifier 25, a battery 26, a motor 27, a second coupling 28, a hydraulic pump 29, and an oil tank 30.

[0036] The suspension actuator cylinder 1 has a first piston assembly 2 inside. The upper chamber of the first piston assembly 2 is the rodless chamber of the suspension actuator cylinder 1, and the lower chamber is the rod chamber of the suspension actuator cylinder 1. The rodless chamber of the suspension actuator cylinder 1 has two oil holes, used for filling and draining oil into the rodless chamber and for allowing hydraulic oil to flow into the hydraulic motor, respectively. The rod chamber of the suspension actuator cylinder 1 has one oil hole, used for filling and draining oil into the rod chamber.

[0037] The first piston assembly 2 mainly includes the first piston 2.1 and the first piston rod 2.2. A blind hole is provided at the center of the first piston rod 2.2, and the top end of the first disc spring 3 is connected to the upper end face 2.3 of the blind hole. The second piston assembly 4 mainly includes the second piston rod 4.1 and the second piston 4.2. The second piston rod 4.1 is inserted upside down into the blind hole of the first piston rod 2.2, and the upper end face 4.3 of the second piston rod is connected to the lower end of the first disc spring 3. A certain space is left between the lower end face 2.5 of the first piston rod and the upper end face 4.4 of the second piston inserted upside down into the blind hole for placing other piezoelectric stacks, disc springs, pads, etc.

[0038] In the rod chamber of the suspension actuator cylinder 1, the second disc spring 5 and the fourth disc spring 11 are provided on the left and right sides of the first piston rod 2.2, and the upper ends of the second disc spring 5 and the fourth disc spring 11 are connected to the lower end face 2.4 of the first piston; the lower ends of the second disc spring 5 and the fourth disc spring 11 are respectively connected to the first pad 6 and the third pad 12 for fixation; the first piezoelectric stack 7 and the third piezoelectric stack 13 are respectively connected below the first pad 6 and the third pad 12, located on the bottom end face of the rod chamber of the suspension actuator cylinder 1.

[0039] The second piston rod 4.1 is provided with the third disc spring 10 and the fifth disc spring 16 on its left and right sides, and the lower ends of the third disc spring 10 and the fifth disc spring 16 are connected to the upper end face 4.4 of the second piston; the upper ends of the third disc spring 10 and the fifth disc spring 16 are respectively connected to the second pad 9 and the fourth pad 15 for fixation; the second piezoelectric stack 8 and the fourth piezoelectric stack 14 are respectively connected above the second pad 9 and the fourth pad 15, and the upper ends of the second piezoelectric stack 8 and the fourth piezoelectric stack 14 are connected to the lower end face 2.5 of the first piston rod.

[0040] The diode 17 is connected to the plurality of piezoelectric stacks via wires, and is used to unidirectionally transfer and store the energy generated by the deformation of the first piezoelectric stack 7, the second piezoelectric stack 8, the third piezoelectric stack 13, and the fourth piezoelectric stack 14 into the supercapacitor group 18.

[0041] The energy stored in the supercapacitor group 18 is transmitted to the electronic control unit 19 through wires. The electronic control unit 19 provides energy to the high-speed switching valve group 20 according to the movement of the piston rod. The high-speed switching valve group 20 supplies oil to and returns oil to the rod chamber and rodless chamber of the suspension actuator 1 by adjusting the switching state.

[0042] The hydraulic motor 22 is connected to the rodless chamber of the suspension actuator 1 via hydraulic lines. Hydraulic oil in the rodless chamber of the suspension actuator 1 flows into the hydraulic motor 22, causing the rotor of the hydraulic motor 22 to rotate. The rotor of the hydraulic motor 22 is connected to the permanent magnet generator 24 via the first coupling 23, further driving the rotor of the permanent magnet generator 24 to rotate, further cutting the permanent magnet to generate electrical energy. The copper wire winding of the permanent magnet generator 24 transmits the generated electrical energy to the rectifier 25 through wires, converting the alternating current into direct current, and then storing it in the battery 26 through wires.

[0043] The battery 26 supplies the stored energy to the motor 27 via wires. The motor 27 drives the hydraulic pump 29 via the second coupling 28 to draw hydraulic oil from the oil tank 30 and supply it to the high-speed switching valve assembly 20.

[0044] Preferably, this embodiment discloses an energy recovery method for a hydropneumatic suspension. This method, during the operation of the hydropneumatic suspension, performs dual-scale recovery of the vibration energy generated by the up-and-down movement of the first piston assembly 2 and the second piston assembly 4, and uses the recovered energy to power the high-speed switching valve assembly 20 and the hydraulic pump 29. The energy recovery method for the hydropneumatic suspension is described in detail below:

[0045] Please see Figures 1 to 4In this embodiment, it is assumed that the compressibility of the first disc spring 3 is slightly greater than the sum of the compressibility of the third disc spring 10 and the fifth disc spring 16 and the deformability of the second piezoelectric stack 8 and the fourth piezoelectric stack 14, and the compressibility of the second disc spring 5 and the fourth disc spring 11 and the sum of the deformability of the first piezoelectric stack 7 and the third piezoelectric stack 13.

[0046] The first-scale energy recovery step: When the first piston assembly 2 moves, hydraulic oil in the rodless chamber of the suspension actuator 1 flows into the hydraulic motor 22. The pressure and flow of the hydraulic oil drive the rotor or piston of the hydraulic motor 22, causing the hydraulic motor 21 to rotate. The hydraulic motor 22 drives the rotor 23.1 of the permanent magnet generator 24 to rotate via the first coupling 23. When the rotor 23.1 rotates, the magnetic field of the permanent magnet passes through the copper wire winding 23.3 of the stator 23.2, generating an induced electromotive force, thereby producing electrical energy. Since the electrical energy generated by the permanent magnet generator 24 is alternating current (AC), a rectifier 25 is needed to convert the AC to direct current (DC) and store it in the battery 26.

[0047] The second-scale energy recovery step involves a piezoelectric stack that is both internally integrated into the suspension actuator 1 and externally positioned between the lower end face 2.5 of the first piston rod and the upper end face 4.4 of the second piston. The piezoelectric stack deforms and generates electrical energy when the hydropneumatic suspension is in either a stretched or compressed state. Therefore, energy recovery methods for the hydropneumatic suspension in both stretched and compressed states are described separately.

[0048] (1) When the hydropneumatic suspension is in a compressed state, it recovers energy by relying on the second piezoelectric stack 8 and the fourth piezoelectric stack 14 between the lower end face 2.5 of the first piston rod and the upper end face 4.4 of the second piston. The hydropneumatic suspension is compressed, causing the second piston assembly 4 to move upward. The second piston rod 4.1 compresses the first disc spring 3, and the second piston 4.2 compresses the third disc spring 10 and the fifth disc spring 16, causing them to deform. The third disc spring 10 and the fifth disc spring 16 compress the second piezoelectric stack 8 and the fourth piezoelectric stack 14 through the second pad 9 and the fourth pad 15, and cause them to begin to deform, generating electrical energy stored in the supercapacitor group 18. When the second piezoelectric stack 8 and the fourth piezoelectric stack 14 reach their maximum deformation, the second piston assembly 4 continues to move upward, causing the third disc spring 10 and the fifth disc spring 16 to be gradually compressed to their limit; when the third disc spring 10 and the fifth disc spring 16 can no longer be compressed, the first disc spring 3 is gradually compressed to its limit. When the first disc spring 3 cannot be compressed, the second piston assembly 4 pushes the first piston assembly 2 to move upward together.

[0049] (2) When the hydropneumatic suspension is in a stretched state, it recovers energy by relying on the first piezoelectric stack 7 and the third piezoelectric stack 13 built into the rod chamber of the suspension actuator 1. The stretching of the hydropneumatic suspension causes the first piston assembly 2 to move downward. The first piston 2.1 compresses the second disc spring 5 and the fourth disc spring 11, causing them to deform. The second disc spring 5 and the fourth disc spring 11 compress the first piezoelectric stack 7 and the third piezoelectric stack 13 through the first pad 6 and the third pad 12, causing them to begin to deform and generate electrical energy stored in the supercapacitor group 18. When the first piezoelectric stack 7 and the third piezoelectric stack 13 reach their maximum deformation, the first piston assembly 2 continues to move downward, causing the second disc spring 5 and the fourth disc spring 11 to be gradually compressed to their limit. When the second disc spring 5 and the fourth disc spring 11 can no longer be compressed, the first disc spring 3 is gradually compressed to its limit by the first piston rod 2.2. When the first disc spring 3 can no longer be compressed, the first piston assembly 2 pushes the second piston assembly 4 to move downward together.

[0050] The energy stored in the supercapacitor bank 18 is used by the electronic control unit 19 to determine whether to supply power to the high-speed switching valve group 20. The logic is as follows: the electronic control unit 19 can monitor the enable signal of the high-speed switching valve group 20. When the electronic control unit 19 detects the rising edge of the enable signal of a certain high-speed switching valve, it controls the MOSFET in the electronic control unit 19 to turn on, thereby transferring the energy in the supercapacitor bank 18 to the coil of the high-speed switching valve, so that the high-speed switching valve is turned on.

[0051] Therefore, regardless of whether the hydropneumatic suspension is in a compressed or stretched state, large-scale recovery of suspension vibration energy can be achieved through "hydraulic motor - coupling - permanent magnet generator - rectifier - battery"; when the hydropneumatic suspension is in a compressed or stretched state, small-scale recovery of suspension vibration energy is achieved through "disc spring - piezoelectric stack - diode - supercapacitor group" by relying on the piezoelectric stack externally placed in the first piston assembly 2 and the second piston assembly 4, and the piezoelectric stack internally placed in the rod cavity of the suspension actuator 1, respectively.

[0052] As can be seen from the above results, the control method proposed in this invention can realize energy recovery of the hydropneumatic suspension.

[0053] Those skilled in the art will understand that the above embodiments and descriptions are merely the principles of the present invention, but the scope of protection of the present invention is not limited thereto. Any transformations and substitutions that involve the scope of the present invention should be included within the scope of protection of the present invention.

Claims

1. An energy recovery method for hydropneumatic suspension, characterized in that, The method is implemented through an energy recovery system, which includes: Suspension actuator; The piston assembly includes a first piston assembly and a second piston assembly, and each piston assembly consists of a piston and a piston rod. The first piston assembly is disposed in the suspension actuator cylinder and is divided into a rodless chamber and a rod chamber. A blind hole is provided at the center of the lower end face of the first piston rod of the first piston assembly, and the second piston rod of the second piston assembly is inserted backward into the blind hole of the first piston rod. The piezoelectric stack includes a first piezoelectric stack, a second piezoelectric stack, a third piezoelectric stack, and a fourth piezoelectric stack. The first piezoelectric stack and the third piezoelectric stack are connected to the bottom surface of the rod cavity of the suspension actuator, and the second piezoelectric stack and the fourth piezoelectric stack are connected between the first piston assembly and the second piston assembly. A pad, the pad comprising a first pad, a second pad, a third pad, and a fourth pad; The disc springs include a first disc spring, a second disc spring, a third disc spring, a fourth disc spring, and a fifth disc spring. The top end of the first disc spring is connected to the upper end face of a blind hole opened on the lower end face of the first piston rod, and the bottom end of the first disc spring is connected to the upper end face of the second piston rod. The second disc spring and the fourth disc spring are respectively placed on the left and right sides of the first piston rod, and the top ends of the second disc spring and the fourth disc spring are connected to the lower end face of the first piston rod, the bottom end of the second disc spring is connected to the top end of the first pad, and the bottom end of the fourth disc spring is connected to the top end of the third pad. The third disc spring and the fifth disc spring are respectively placed on the left and right sides of the second piston rod, and the bottom ends of the third disc spring and the fifth disc spring are connected to the upper end face of the second piston rod, the top end of the third disc spring is connected to the bottom end of the second pad, and the top end of the fifth disc spring is connected to the bottom end of the fourth pad. The piezoelectric stack is connected to the diode via a wire, which unidirectionally transfers energy to the supercapacitor bank. The supercapacitor bank is connected to the electronic control unit via a wire, which supplies the energy stored in the supercapacitor bank to the high-speed switching valve group through the electronic control unit. The hydraulic motor is connected to the rodless chamber of the suspension actuator via hydraulic lines. The rotor of the hydraulic motor is connected to the rotor of the permanent magnet generator via a first coupling, driving the permanent magnet generator to rotate and generate energy. The energy generated by the permanent magnet generator is alternating current, which is converted into direct current by a rectifier, stored in a battery, and used to power the motor. The energy recovery method includes the following steps: First-scale energy recovery step: When the piston assembly reciprocates, the hydraulic oil in the rodless chamber of the suspension actuator flows into the hydraulic motor; the combined action of the hydraulic oil pressure and flow rate drives the motor rotor to rotate, and the motor output shaft drives the permanent magnet generator rotor to rotate at high speed through the first coupling, and the stator winding cuts the magnetic field lines to generate three-phase alternating current; after the alternating current is converted into direct current by the rectifier, it is directly stored in the battery and powers the motor. Second-scale energy recovery step: Building upon the first-scale energy recovery, the system simultaneously deploys piezoelectric stacks. (1) Compression stroke: The second piston assembly moves upward, and the second and fourth piezoelectric stacks are compressed step by step by the first, third and fifth disc springs to generate electrical energy; (2) Extension stroke: The second piston assembly moves downward, and the first and third piezoelectric stacks built into the rod cavity of the suspension actuator are compressed in the opposite direction by the second and fourth disc springs, generating electrical energy; The electrical energy generated by the two sets of piezoelectric stacks is rectified in parallel and then fed into the supercapacitor bank. The control unit decides whether to supply power to the high-speed switching valve group.

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