Fuel pump assembly with pressure release valve for new energy hybrid vehicle

Abstract

The invention relates to the technical field of new energy vehicles, in particular to a fuel pump assembly with a pressure relief valve for a new energy hybrid power vehicle, and adopts the technical scheme that the fuel pump assembly comprises a pump head mechanism, an oil conveying mechanism and a pressure relief mechanism, a first diaphragm, a first jacking frame, a second jacking frame and a second diaphragm are clamped between the diaphragm supporting frame and the oil conveying shell, and the first jacking frame is arranged on the periphery of the second jacking frame in a sleeving mode and used for enabling stress to be evenly distributed in the center areas and the edge areas of the first diaphragm and the second diaphragm in the reciprocating motion process of the diaphragms; the pressure relief mechanism comprises a pressure relief valve body and a corrugated connecting pipe, one end of the corrugated connecting pipe is connected with the outlet end of the pressure relief valve body, the other end of the corrugated connecting pipe communicates with an oil inlet channel of the oil conveying mechanism, and the corrugated connecting pipe is used for conducting pressure relief fluid through flexible deformation when the system pressure exceeds the limit. The problems that under the high-frequency vibration working condition of the hybrid electric vehicle, the diaphragm is prone to cracking, and leakage is prone to occurring at the pressure relief connecting position are solved.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle technology, specifically to a fuel pump assembly for new energy hybrid vehicles with a pressure relief valve. Background Technology

[0002] Against the backdrop of the rapid development of new energy hybrid vehicle technology, the fuel pump assembly, as a core component connecting the fuel tank and the engine fuel supply system, directly affects the stability of the vehicle's power output and driving safety. Hybrid vehicles, due to frequent engine start-stop cycles, drastic dynamic fluctuations in fuel line pressure, and complex vibration spectra in their operating environment, place far more stringent demands on the vibration resistance of key fuel pump connections and the fatigue durability of core sealing components than traditional gasoline vehicles. Currently, the industry generally adopts a traditional architecture combining a single diaphragm pump chamber and an independent pressure relief module. While this can maintain basic functions under normal operating conditions, its structural design's insufficient matching with actual operating conditions becomes increasingly apparent in the high-dynamic load scenarios unique to hybrid systems.

[0003] In existing technologies, fuel pump diaphragm assemblies typically employ a single-layer diaphragm with a central return spring, where the force of the return spring is directly concentrated at the diaphragm's central drive point. The pressure relief valve's outlet is generally rigidly connected to the fuel circuit using a metal conduit. However, under the combined conditions of high-frequency vibration and transient pressure changes in hybrid vehicles, the driving and return forces are highly concentrated in the central region of the diaphragm assembly, resulting in a significant stress gradient between the diaphragm's edge fixing area and the central drive point. This localized stress continuously exceeds the material's fatigue limit, triggering early microcracks in the diaphragm that propagate rapidly, leading to pump chamber seal failure. Simultaneously, the rigid connection structure of the pressure relief outlet lacks deformation buffering capacity, making the connection interface prone to fretting wear and loosening under continuous vibration, significantly increasing the risk of seal failure. These structural defects make it difficult for existing fuel pumps to meet the safety requirements for long-term reliable operation in hybrid applications.

[0004] Therefore, there is an urgent need to develop a fuel pump assembly with a pressure relief valve for new energy hybrid vehicles to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a fuel pump assembly for new energy hybrid vehicles with a pressure relief valve, which has the advantages of fatigue resistance of double-layer diaphragm and vibration resistance of corrugated connecting pipe, effectively solving the problems of easy cracking of diaphragm and easy leakage at pressure relief connection under high-frequency vibration conditions of hybrid vehicles.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a fuel pump assembly for a new energy hybrid vehicle with a pressure relief valve, comprising a pump head mechanism, an oil delivery mechanism, and a pressure relief mechanism. The pump head mechanism includes a diaphragm support frame, and a first diaphragm, a first lifting frame, a second lifting frame, and a second diaphragm are clamped between the diaphragm support frame and the oil delivery housing. The first lifting frame is sleeved on the outer periphery of the second lifting frame, and is used to ensure uniform force distribution between the central and edge regions of the first and second diaphragms during the reciprocating motion of the diaphragms. The pressure relief mechanism includes a pressure relief valve body and a corrugated connecting pipe. One end of the corrugated connecting pipe is connected to the outlet end of the pressure relief valve body, and the other end is connected to the oil inlet channel of the oil delivery mechanism, and is used to conduct pressure relief fluid through flexible deformation when the system pressure exceeds the limit.

[0007] Preferably, it also includes a drive mechanism, the drive mechanism including a protective shell, a transmission cam rotatably mounted inside the protective shell via a sealed bearing, a lifting block rotatably mounted on the transmission cam, a servo motor fixedly mounted on the side of the protective shell, and the transmission shaft of the servo motor connected to the transmission cam; When the above technical solution is adopted, the sealed bearing effectively prevents fuel medium from entering the drive cavity, the servo motor provides precise and controllable speed and torque output, and the rotational cooperation between the lifting block and the transmission cam smoothly converts the rotary motion into linear reciprocating motion, which significantly improves the drive response accuracy and motion stability under high-frequency start-stop conditions and reduces transmission shock.

[0008] Preferably, the pump head mechanism further includes a lifting shaft, a lifting elastic element, and a lifting cover. The top of the lifting shaft passes through the lifting cover, the first diaphragm, the first lifting frame, the second lifting frame, and the second diaphragm sequentially along the axial direction. The lifting elastic element is sleeved on the outer periphery of the lifting shaft and supported below the lifting cover. The lifting cover is sleeved on the lifting shaft and its top surface abuts against the bottom surface of the first diaphragm. The diaphragm support frame is also provided with a mounting bracket and a communicating cavity. The mounting bracket is used for fixed installation of the assembly, and the communicating cavity is used to accommodate the lifting block and communicate with the protective shell. When the above technical solution is adopted, the lifting cover evenly distributes the driving force to the central area of ​​the first diaphragm. With the nested layout of the first lifting frame and the second lifting frame, the stress distribution of the central driving area and the edge fixed area of ​​the double-layer diaphragm tends to be uniform during the reciprocating motion, effectively suppressing the initiation of microcracks caused by local stress concentration. The lifting elastic component provides a stable restoring force, and the connecting cavity ensures the sealing and connection of the driving end, thereby improving the fatigue life and sealing reliability of the diaphragm assembly under high-frequency vibration conditions.

[0009] Preferably, the pressure relief mechanism further includes a top cover, which is fixedly installed at the top opening of the oil supply housing, and the pressure relief valve body is installed on the top cover; When the above technical solution is adopted, the top cover and the oil supply housing form a rigid sealing connection interface, which enhances the structural rigidity of the pressure relief valve mounting base, effectively resists the loosening of the connection caused by system pressure fluctuations and external vibrations, and ensures that the pressure relief valve body maintains sealing integrity and operational reliability during long-term operation.

[0010] Preferably, the oil conveying mechanism further includes an oil inlet pipe and an oil outlet pipe, which are integrally formed on both sides of the oil conveying shell. An oil inlet connector is installed at the end of the oil inlet pipe, and an oil outlet connector is installed at the end of the oil outlet pipe. The other end of the corrugated connecting pipe is sealed and connected to the connecting hole on the side wall of the oil inlet pipe. When the above technical solution is adopted, the integrated structure of the oil delivery shell and the inlet and outlet oil pipes eliminates the need for welding or threaded connection interfaces, significantly reducing potential leakage points; the inlet and outlet oil joints enable rapid connection of pipelines; the corrugated connection pipe and the inlet oil pipe connection design allow the pressure relief fluid to flow back to the low-pressure inlet oil channel, avoiding high pressure impact on downstream pipelines, while using the inlet oil channel to buffer the pressure relief energy.

[0011] Preferably, the bottom of the oil delivery housing has an inner groove, the opening at the bottom of the inner groove is sealed by a second diaphragm, the oil delivery housing has an oil delivery chamber, the bottom of the oil delivery chamber has an opening on one side, and a first sealing element is elastically installed therethrough by a first elastic element; the other side of the oil delivery housing adjacent to the oil inlet pipe has an opening for communication between the oil delivery chamber and the inner groove, and a second sealing element is elastically installed therethrough by a second elastic element, the lower end face of the second sealing element is in contact with the outer surface of the second diaphragm; When the above technical solution is adopted, the inner groove and the second diaphragm form an independent sealed chamber. The second seal achieves dynamic fitting and sealing under the push of the diaphragm. The first seal and the second seal work together to significantly improve the bidirectional sealing stability of the oil delivery chamber under pressure alternation and vibration conditions, and effectively prevent fuel leakage.

[0012] Preferably, a positioning frame is fixedly installed inside the oil delivery housing, and the positioning frame is connected to the oil delivery housing by positioning bolts; When the above technical solution is adopted, the positioning frame provides a vertical motion guide track for the first seal and the second seal, constrains the movement trajectory of the seal, avoids uneven wear, jamming or tilting of the sealing surface, ensures uniform pressure on the sealing surface, maintains long-term stable sealing performance, and extends the service life of key sealing components.

[0013] Preferably, the drive shaft and the drive cam are connected by a key, and the lifting block and the drive cam are connected by a revolute joint; When the above technical solution is adopted, the key connection structure ensures that the power transmission is free from slippage and lag, and the rotating pair connection significantly reduces the friction coefficient and wear rate of the contact surface between the lifting block and the transmission cam, improves the transmission efficiency and motion smoothness, and enhances the durability and reliability of the drive mechanism under millions of reciprocating working conditions.

[0014] Preferably, the oil inlet and outlet connectors adopt a quick-connect interface structure; When the above technical solution is adopted, the quick-connect interface enables the rapid installation and removal of fuel lines and self-locking sealing. The internal sealing elements and snap-fit ​​structure of the interface effectively resist loosening and displacement caused by vibration during vehicle operation, improve assembly efficiency and connection reliability, and reduce on-site maintenance time and cost.

[0015] Preferably, the corrugated connecting pipe is a metal braided flexible hose structure; When the above technical solution is adopted, the metal braided layer provides high strength pressure resistance and fatigue resistance, and the bellows body provides flexible deformation capabilities for axial compression, tension and radial bending. It effectively absorbs high-frequency vibration, thermal expansion and contraction displacement and installation tolerance during the operation of hybrid vehicles, avoids stress concentration and fretting wear at the connection interface, and significantly improves the sealing durability and structural safety of the pressure relief channel under complex dynamic conditions.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention, through a pump head mechanism comprising a first diaphragm, a first lifting frame, a second lifting frame, and a second diaphragm held and fixed by a diaphragm support frame and an oil delivery housing, wherein the first lifting frame is sleeved around the outer periphery of the second lifting frame to form a nested driving structure, allows the driving force to be synergistically transmitted to the center and edge regions of the double-layer diaphragm during the reciprocating motion of the diaphragm via the double-layer lifting frame. This effectively balances the stress distribution between the first and second diaphragms, significantly reduces the stress gradient between the edge fixing area and the central driving point, and prevents local stress from continuously exceeding the material fatigue limit, thereby inhibiting the initiation and propagation of microcracks and improving the performance of the diaphragm assembly in high-frequency start-stop systems of hybrid vehicles. It improves fatigue life under vibration conditions; at the same time, by setting a corrugated connecting pipe in the pressure relief mechanism that connects the outlet end of the pressure relief valve body to the oil inlet channel of the oil supply mechanism, it uses its axial and radial flexible deformation capability to absorb high-frequency vibration, thermal expansion and contraction displacement and installation deviation during vehicle operation, replacing the hard connection method of traditional rigid metal pipes, effectively eliminating stress concentration and fretting wear risk at the connection interface, ensuring the sealing integrity and structural stability of the pressure relief fluid conduction path, and effectively solving the problem of early diaphragm cracking and leakage failure at the pressure relief connection caused by the violent dynamic fluctuation of oil circuit pressure and complex vibration spectrum in hybrid vehicles. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the main structure of the present invention; Figure 2This is a frontal cross-sectional view of the present invention. Figure 3 This is a schematic diagram of the pump head mechanism of the present invention; Figure 4 This is a schematic diagram of the disassembled drive mechanism of the present invention; Figure 5 This is a schematic diagram of the oil conveying mechanism of the present invention; Figure 6 This is a schematic diagram of the left-side cross-sectional structure of the oil delivery mechanism of the present invention; Figure 7 This is a schematic diagram of the pressure relief mechanism of the present invention.

[0018] In the diagram: 1. Drive mechanism; 11. Protective shell; 111. Sealed bearing; 12. Transmission cam; 13. Lifting block; 14. Servo motor; 141. Transmission shaft; 2. Pump head mechanism; 21. Diaphragm support frame; 211. First diaphragm; 212. First lifting frame; 213. Second lifting frame; 214. Second diaphragm; 215. Lifting connecting shaft; 216. Lifting elastic element; 217. Lifting cover; 22. Mounting bracket; 23. Connecting cavity 3. Oil delivery mechanism; 31. Oil delivery housing; 311. Oil delivery chamber; 312. First seal; 313. First elastic element; 314. Second seal; 315. Second elastic element; 316. Inner groove; 32. Positioning frame; 321. Positioning bolt; 33. Oil outlet pipe; 331. Oil outlet connector; 34. Oil inlet pipe; 341. Oil inlet connector; 4. Pressure relief mechanism; 41. Top cover; 42. Pressure relief valve body; 43. Corrugated connecting pipe. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: As Figures 1 to 7 As shown, one embodiment of the present invention is provided: a fuel pump assembly for a new energy hybrid vehicle with a pressure relief valve, including a drive mechanism 1, a pump head mechanism 2, an oil delivery mechanism 3 and a pressure relief mechanism 4, wherein the top of the drive mechanism 1 is fixedly connected to the pump head mechanism 2 by connecting bolts, the top of the pump head mechanism 2 is mounted with the oil delivery mechanism 3 by connecting bolts, and the top of the oil delivery mechanism 3 is connected to the pressure relief mechanism 4 by threads. The drive mechanism 1 is used to provide power to drive the pump head mechanism 2 to reciprocate, so as to realize the intake and output of fuel; The pump head mechanism 2 is used to generate periodic pressure changes under the action of the drive mechanism 1 to complete the pressurized delivery of fuel; The fuel delivery mechanism 3 is used to export and deliver the high-pressure fuel generated by the pump head mechanism 2 to the engine fuel supply system; The pressure relief mechanism 4 is used to automatically open the pressure relief channel when the system pressure rises abnormally, to prevent the oil circuit system from being damaged by overpressure.

[0021] Specifically, the drive mechanism 1 includes a protective housing 11. A transmission cam 12 is rotatably mounted inside the protective housing 11 via a sealed bearing 111. A lifting block 13 is rotatably mounted on the top of the transmission cam 12 via a pin. A servo motor 14 is fixedly mounted on one side of the protective housing 11 via a vibration damping pad. The transmission shaft 141 on the servo motor 14 is connected to the transmission cam 12 via a spline key. The speed control circuit, speed feedback module, and communication protocol with the vehicle ECU of the servo motor 14 are well-known technologies in the art and will not be explained here.

[0022] The pump head mechanism 2 includes a diaphragm support frame 21. A communicating cavity 23 is welded to the top of the diaphragm support frame 21, and an mounting frame 22 is welded to the back of the communicating cavity 23. The top of the diaphragm support frame 21 sequentially clamps and installs a first diaphragm 211, a first lifting frame 212, a second lifting frame 213, and a second diaphragm 214 from bottom to top. The first lifting frame 212 is sleeved on the outer periphery of the second lifting frame 213 to form a nested driving structure, with a buffer gap of 0.20mm±0.05mm reserved between them. The first lifting frame 212 is clamped on the opposite side of the first diaphragm 211 and the second diaphragm 214. The second lifting frame 213 is rigidly connected to the top of the lifting shaft 215 by a nut. During the oil suction stroke, the lifting shaft 215 moves upward and pushes the lifting cover 217 upward, thereby pushing the central area of ​​the second diaphragm 214 to bulge upward to form an initial deformation wave. After the buffer gap is eliminated, the first lifting frame 212 is pushed simultaneously, so that the edge area of ​​the first diaphragm 211 deforms upward in tandem, forming a double-curvature wave-shaped profile that smoothly transitions from the center to the edge. During the oil pressure stroke, the lifting elastic element 216 releases stored energy, and the double-layer lifting frame guides the double-layer diaphragm to rebound evenly along the original deformation path to the initial plane state. This nested drive structure allows the driving force to be transmitted to the center and edge regions of the double-layer diaphragm through the double-layer lifting frame during the reciprocating motion of the diaphragm. This balances the stress distribution of the first diaphragm 211 and the second diaphragm 214, reduces the stress gradient between the edge fixed area and the center drive point, and experimentally verified a reduction of 38% to 45%. It also prevents local stress from continuously exceeding the fatigue limit of the fluororubber material of about 18MPa, inhibits the initiation and propagation of microcracks, and improves the fatigue life of the diaphragm assembly under the high-frequency start-stop conditions of hybrid vehicles with a start-stop frequency of not less than 8 times / min and a vibration acceleration of not less than 0.5g under vibration conditions. Accelerated life tests have verified that the life is improved by not less than 2.1 times. A lifting cover 217 is fitted on the lifting shaft 215 inside the diaphragm support frame 21. The top of the lifting cover 217 contacts the bottom of the first diaphragm 211 but is not fixedly connected. A lifting spring 216 is fitted on the lifting shaft 215 below the lifting cover 217. The lifting spring 216 is a helical compression spring located on the outside of the lifting shaft 215 below the lifting cover 217. When the lifting block 13 rises, it pushes the lifting shaft 215 upward, compressing the lifting elastic element 216, causing the first diaphragm 211 and the second diaphragm 214 to deform upward simultaneously, expanding the pump chamber volume and realizing the oil suction process; when the lifting block 13 falls, the lifting elastic element 216 rebounds, pushing the lifting shaft 215 downward, and the double-layer diaphragm returns to its original state, compressing the pump chamber volume and completing the oil pressing action.

[0023] The oil delivery mechanism 3 includes an oil delivery housing 31. An oil delivery chamber 311 is provided on one side inside the oil delivery housing 31. A first sealing element 312 is elastically installed in the oil delivery housing 31 through an opening and a first elastic element 313. The first sealing element 312 is located above the first elastic element 313. The first elastic element 313 is a compression spring, which is used to maintain the continuous sealing pressure of the first sealing element 312 on the outlet of the oil delivery chamber 311. A positioning frame 32 is fixedly installed on the inner side of the oil supply housing 31 by positioning bolts 321. The positioning frame 32 is used to support and guide the vertical movement of the first sealing element 312. One side of the oil tank 31 has an integrally formed oil inlet pipe 34, on which an oil inlet connector 341 is installed; the other side has an integrally formed oil outlet pipe 33, on which an oil outlet connector 331 is installed. The oil inlet pipe 34 has a connection hole on the side wall near the pressure relief mechanism 4. The connection hole has an internal thread for connecting and installing with the pressure relief mechanism 4. The bottom of the oil conveying housing 31 has an inner groove 316. The inner groove 316 has no structure inside, and its bottom surface is open and sealed by the second diaphragm 214. An opening on the inner side of the oil supply housing 31, near the oil inlet pipe 34, is connected to the inner groove 316. A second seal 314 is elastically installed through a second elastic member 315. The second seal 314 is located below the second elastic member 315 and is pushed by the second diaphragm 214, allowing it to move vertically within the opening. The second elastic member 315 is a tension spring used to dynamically adjust the contact pressure of the second seal 314.

[0024] The pressure relief mechanism 4 includes a top cover 41, which is threadedly installed on the top of the oil supply housing 31. A pressure relief valve body 42 is threadedly installed on the top of the top cover 41. One end of the outlet of the pressure relief valve body 42 is connected to one end of a corrugated connecting pipe 43 by a clamp. The other end of the corrugated connecting pipe 43 is screwed into the connection hole of the oil inlet pipe 34 through a threaded joint with a sealing ring. The corrugated connecting pipe 43 uses a stainless steel corrugated pipe base, covered with a stainless steel wire braided reinforcement layer, and has 8 uniform annular corrugations on the pipe wall. The axial compensation is ±6mm, the radial deflection angle is ±4°, and the burst pressure is not less than 3.5MPa. This structure utilizes its axial and radial flexible deformation capabilities to absorb high-frequency vibrations (50Hz to 500Hz), thermal expansion and contraction displacement (-40℃ to +120℃), cumulative displacement of no more than 4mm, and installation deviation (radial deviation of no more than 1.5mm) during vehicle operation. When the fuel system pressure exceeds the set threshold of 0.65MPa±0.05MPa in the pressure relief valve body 42, the piston inside the pressure relief valve body 42 automatically moves upward to open the pressure relief channel, and the high-pressure fuel is guided to the low-pressure area of ​​the fuel inlet pipe 34 through the corrugated connecting pipe 43.

[0025] This structural design uses the servo motor 14 of the drive mechanism 1 to drive the transmission cam 12, which in turn drives the lifting block 13 to achieve precise reciprocating motion. This, in turn, drives the double-layer diaphragm assembly in the pump head mechanism 2 to complete the oil suction and pressure cycle. Combined with the sealing and guiding structure of the oil delivery mechanism 3, it achieves stable pressurized fuel delivery. The pressure relief mechanism 4 and the oil delivery mechanism 3 form a closed-loop pressure relief circuit, which can respond to pressure relief when the system pressure is abnormal, thereby improving the safety and reliability of the fuel pump assembly under the complex operating conditions of hybrid vehicles.

[0026] Example 2: To further optimize the structural strength and sealing performance of the pump head mechanism 2, and to enhance the stability of the internal flow channel of the oil delivery mechanism 3, such as... Figure 1 , Figure 2 , Figure 3 , Figure 5 and Figure 6 As shown, this embodiment is optimized based on embodiment one as follows: the diaphragm support frame 21 of the pump head mechanism 2 is precision die-cast from high-strength aluminum alloy material, and its top is provided with radially distributed reinforcing ribs; The first diaphragm 211 and the second diaphragm 214 are both made of fluororubber and aramid fiber composite material by compression molding and vulcanization, with an elastic recovery rate of not less than 95%; the contact surfaces of the first lifting frame 212 and the second lifting frame 213 are mirror polished with a roughness Ra value of not more than 0.4μm, and the buffer gap between them is precisely controlled at 0.22mm±0.03mm. The lifting shaft 215 is a hollow cylindrical structure with a stepped surface at the top; the lifting elastic element 216 is a helical compression spring with a pre-compression amount of 3mm, maintaining a preload of 15N to 18N within the maximum stroke range of 8mm. The oil conveying mechanism 3's oil conveying shell 31 is formed by high-pressure casting of aluminum alloy, and the surface is treated with hard anodizing with a film thickness of 25μm±5μm; the oil conveying chamber 311 is provided with a spiral guide groove with a groove depth of 1.5mm, a groove width of 3mm, and a lead of 30mm. The first sealing element 312 is a composite disc-shaped structure with an outer diameter of 28 mm and a thickness of 3 mm, made of polytetrafluoroethylene coated with fluororubber. It is embedded in the opening in the inner wall of the oil conveying housing 31 and is clamped by the first elastic element 313 with a pressure of 12 N to 15 N. The second seal 314 is made of the same composite material and is installed in the transition sealing area between the positioning frame 32 and the oil supply housing 31. It is provided with a tensile tension of 8N to 10N by the second elastic element 315. In addition, both the oil inlet connector 341 and the oil outlet connector 331 adopt quick-connect interfaces; the corrugated connecting pipe 43 adopts a metal braided hose structure.

[0027] Example 3: In order to achieve efficient linkage and improved pressure response sensitivity between the oil delivery mechanism 3 and the pressure relief mechanism 4, such as... Figure 1 , Figure 2 , Figure 6 and Figure 7 As shown, this embodiment is optimized based on embodiment one as follows: the top of the oil supply housing 31 is provided with a precision internal thread, and it is sealed to the external thread on the top cover 41 of the pressure relief mechanism 4 by means of sealant. The pressure relief valve body 42 has a piston inside, a pressure regulating spring above the piston, and an adjustment knob on top. By rotating the adjustment knob, the preload of the pressure regulating spring is set, and the pressure relief threshold is adjusted within the range of 0.2MPa to 0.8MPa. One end of the bellows connecting pipe 43 is connected to the outlet flange of the pressure relief valve body 42 by a clamp, and the other end is screwed into the connection hole of the oil inlet pipe 34 through a threaded joint with a sealing ring, forming a closed-loop pressure relief channel. When the system pressure rises to the set threshold, the piston inside the pressure relief valve body 42 moves upward against the resistance of the pressure regulating spring, opening the pressure relief passage. High-pressure fuel is guided to the low-pressure area of ​​the fuel inlet pipe 34 through the corrugated connecting pipe 43. The flexible structure of the corrugated connecting pipe 43 absorbs the displacement caused by temperature changes or vehicle vibration, with an axial displacement of ±3mm and a radial displacement of ±1.2mm. The second elastic element 315 inside the oil supply housing 31 is a tension spring. Its upper end is hooked to the bottom hanging point of the positioning frame 32, and its lower end is hooked to the base hanging point of the oil supply housing 31. As the lifting shaft 215 moves up and down, the second elastic element 315 extends and retracts, adjusting the contact pressure of the second sealing element 314 on the sealing surface to vary from 8N ​​to 10N. The first elastic element 313 is a compression spring. Its upper end abuts against the countersunk hole at the top of the first sealing element 312, and its lower end is supported on the stepped surface of the inner wall of the oil supply housing 31, ensuring that the first sealing element 312 remains in contact under the negative pressure condition of -0.05MPa.

[0028] Example 4: To improve the transmission efficiency, operational smoothness, and environmental adaptability of drive mechanism 1, such as... Figure 1 , Figure 2 , Figure 4As shown, this embodiment is optimized based on embodiment one as follows: the servo motor 14 is a brushless DC motor, and the transmission shaft 141 is provided with a spline that mates with the inner spline groove of the transmission cam 12; the body of the transmission cam 12 is precision forged from alloy structural steel, and the surface is hardened by gas nitriding with a hardening layer depth of 0.35mm to 0.45mm and a surface hardness of HV850 to HV950; the bottom of the lifting block 13 is fitted with a bearing with a friction coefficient of 0.002 to 0.005; Meanwhile, the drive mechanism 1 and the pump head mechanism 2 are connected by connecting bolts, and the connection surface is coated with sealant; the mounting bracket 22 is provided with mounting holes; a double sealing gasket is provided between the diaphragm support frame 21 of the pump head mechanism 2 and the oil delivery housing 31 of the oil delivery mechanism 3; the signal processing circuit, protection module and diagnostic function built into the servo motor 14 are mature technical solutions in this field, and will not be explained here.

[0029] When using this invention, firstly, the drive mechanism 1 is fixed to the designated bracket in the vehicle's power compartment through the mounting holes on the mounting bracket 22, and the protective shell 11 is connected to the pump head mechanism 2 through connecting bolts; then, the oil delivery mechanism 3 is installed on the top of the pump head mechanism 2 through connecting bolts, and then the top cover 41 of the pressure relief mechanism 4 is screwed into the threaded hole on the top of the oil delivery shell 31, with the torque controlled at 15 N·m ± 2 N·m; finally, the oil inlet connector 341 is connected to the fuel tank outlet pipe of the vehicle, and the oil outlet connector 331 is connected to the engine fuel supply rail; After the vehicle is started, the vehicle controller sends a control signal to the servo motor 14. The servo motor 14 operates at the set speed, driving the transmission cam 12 to rotate through the transmission shaft 141. The lifting block 13 moves up and down along the cam profile with a stroke of 8mm and a frequency adjustable from 2Hz to 10Hz. This pushes the lifting shaft 215 to drive the double-layer diaphragm assembly to deform alternately, realizing the intake of fuel and high-pressure output. When the system pressure exceeds the pressure relief threshold, the pressure relief valve body 42 responds and opens. High-pressure fuel is guided to the fuel inlet pipe 34 through the corrugated connecting pipe 43, and the system pressure drops back to a safe range.

[0030] Experimental Verification Section: To objectively verify the technical effects of this invention, systematic comparative experiments were conducted in accordance with relevant technical standards: Sample settings The experimental group consisted of 10 fuel pump assemblies with the structure of Embodiment 1 of the present invention, numbered SY01 to SY10; Control group A is a single-layer diaphragm structure that retains only the first diaphragm 211 and a single top lifting frame, with the rest of the structure being the same as the experimental group. There are 10 units in total, numbered DBA01 to DBA10. Control group B uses a stainless steel rigid conduit to replace the corrugated connecting pipe 43 for the pressure relief connection. The rest of the structure is the same as the experimental group. There are 10 units in total, numbered DBB01 to DBB10. All samples were assembled using the same batch of materials and the same production line.

[0031] Test conditions Start-stop operation: Simulates high-frequency start-stop of a hybrid vehicle 8 times / min, for a total of 100,000 cycles; Vibration conditions: random vibration spectrum from 5 Hz to 500 Hz, PSD value 0.04 g² / Hz, RMS value 0.35 g, for 500 hours; Temperature cycling: -40℃ to +120℃, 2 hours per cycle, 50 cycles in total; Pressure fluctuation: 0.1MPa to 0.8MPa sinusoidal fluctuation, frequency 2Hz, lasting for 300 hours; Fuel medium: 92-octane gasoline meeting China VI standard containing 10% ethanol, temperature 40℃±5℃.

[0032] 3. Test Results

[0033] 4. Conclusion Analysis The experimental group showed a 110.7% (2.11 times) increase in the number of initial crack cycles compared to the control group A, a 43.2% decrease in the stress gradient at the edge center, and a 75% reduction in residual deformation of the diaphragm. The experimental group showed no leakage at the pressure relief connection throughout the entire process, and the maximum stress at the connection interface was reduced by 62.4% compared to control group B. All experimental samples underwent a combined accelerated test of 100,000 start-stop cycles, 500 hours of vibration, and 50 cycles of temperature cycling. No diaphragm cracking, no connection leakage, and no sealing failure were observed. The performance degradation rate was less than 5%, meeting the 150,000-kilometer design life requirement for hybrid vehicles.

[0034] In summary, the present invention solves the problems of early fatigue cracking of the diaphragm and leakage failure at the pressure relief connection of the fuel pump in hybrid vehicles under high-frequency start-stop and complex vibration conditions by the coordinated design of the nested double-layer diaphragm lifting structure in the pump head mechanism 2 and the flexible corrugated connecting pipe 43 in the pressure relief mechanism 4.

[0035] When using this invention, firstly, the drive mechanism 1 is fixed to the designated bracket in the vehicle's power compartment through the mounting holes on the mounting bracket 22, and the protective shell 11 is connected to the pump head mechanism 2 through connecting bolts; then, the oil delivery mechanism 3 is installed on the top of the pump head mechanism 2 through connecting bolts, and then the top cover 41 of the pressure relief mechanism 4 is screwed into the threaded hole on the top of the oil delivery shell 31, with the torque controlled at 15 N·m ± 2 N·m; finally, the oil inlet connector 341 is connected to the fuel tank outlet pipe of the vehicle, and the oil outlet connector 331 is connected to the engine fuel supply rail; After the vehicle is started, the vehicle controller sends a control signal to the servo motor 14. The servo motor 14 operates at the set speed, driving the transmission cam 12 to rotate through the transmission shaft 141. The lifting block 13 moves up and down along the cam profile with a stroke of 8mm and a frequency that is adjustable from 2Hz to 10Hz. This pushes the lifting shaft 215 to drive the double-layer diaphragm assembly to deform alternately, realizing the intake of fuel and high-pressure output. When the system pressure exceeds the pressure relief threshold, the pressure relief valve body 42 responds and opens. The high-pressure fuel is guided to the fuel inlet pipe 34 through the corrugated connecting pipe 43, and the system pressure drops back to a safe range.

[0036] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0037] Furthermore, it should be understood that although this specification describes the embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A fuel pump assembly for a new energy hybrid vehicle with a pressure relief valve, comprising a pump head mechanism (2), a fuel delivery mechanism (3), and a pressure relief mechanism (4), characterized in that: The pump head mechanism (2) includes a diaphragm support frame (21), which holds a first diaphragm (211), a first lifting frame (212), a second lifting frame (213), and a second diaphragm (214) between the diaphragm support frame (21) and the oil delivery housing (31). The first lifting frame (212) is sleeved on the outer periphery of the second lifting frame (213) to ensure that the force is evenly distributed in the central and edge areas of the first diaphragm (211) and the second diaphragm (214) during the reciprocating motion of the diaphragm. The pressure relief mechanism (4) includes a pressure relief valve body (42) and a corrugated connecting pipe (43). One end of the corrugated connecting pipe (43) is connected to the outlet end of the pressure relief valve body (42), and the other end is connected to the oil inlet channel of the oil delivery mechanism (3). It is used to conduct pressure relief fluid through flexible deformation when the system pressure exceeds the limit.

2. The fuel pump assembly for a new energy hybrid vehicle with a pressure relief valve according to claim 1, characterized in that, It also includes a drive mechanism (1), which includes a protective shell (11). A transmission cam (12) is rotatably mounted inside the protective shell (11) via a sealed bearing (111). A lifting block (13) is rotatably mounted on the transmission cam (12). A servo motor (14) is fixedly mounted on the side of the protective shell (11). The transmission shaft (141) of the servo motor (14) is connected to the transmission cam (12) to convert the rotational motion into linear reciprocating motion to drive the pump head mechanism (2).

3. A fuel pump assembly for a new energy hybrid vehicle with a pressure relief valve according to claim 2, characterized in that, The pump head mechanism (2) further includes a lifting shaft (215), a lifting elastic member (216), and a lifting cover (217). The top of the lifting shaft (215) passes through the lifting cover (217), the first diaphragm (211), the first lifting frame (212), the second lifting frame (213), and the second diaphragm (214) in sequence along the axial direction. The lifting elastic member (216) is sleeved on the outer periphery of the lifting shaft (215) and supported below the lifting cover (217). The lifting cover (217) is sleeved on the lifting shaft (215) and its top surface abuts against the bottom surface of the first diaphragm (211). The diaphragm support frame (21) is also provided with a mounting frame (22) and a communicating cavity (23). The mounting frame (22) is used for assembly fixing and the communicating cavity (23) is used to accommodate the lifting block (13) and communicate with the protective shell (11).

4. The fuel pump assembly for a new energy hybrid vehicle with a pressure relief valve according to claim 1, characterized in that, The pressure relief mechanism (4) also includes a top cover (41), which is fixedly installed at the top opening of the oil supply housing (31). The pressure relief valve body (42) is installed on the top cover (41) to achieve a sealed assembly between the pressure relief valve body (42) and the oil supply housing (31).

5. A fuel pump assembly for a new energy hybrid vehicle with a pressure relief valve according to claim 1, characterized in that, The oil delivery mechanism (3) also includes an oil inlet pipe (34) and an oil outlet pipe (33). The oil inlet pipe (34) and the oil outlet pipe (33) are integrally formed on both sides of the oil delivery housing (31). An oil inlet connector (341) is installed at the end of the oil inlet pipe (34), and an oil outlet connector (331) is installed at the end of the oil outlet pipe (33). The other end of the corrugated connecting pipe (43) is sealed and connected to the connecting hole on the side wall of the oil inlet pipe (34) to form a fuel input and output channel and a pressure relief fluid return path.

6. A fuel pump assembly for a new energy hybrid vehicle with a pressure relief valve according to claim 5, characterized in that, The bottom of the oil delivery housing (31) is provided with an inner groove (316), and the opening at the bottom of the inner groove (316) is sealed by a second diaphragm (214). The oil delivery housing (31) is provided with an oil delivery chamber (311), and the bottom of the oil delivery chamber (311) is opened on one side, and a first sealing element (312) is elastically installed through a first elastic element (313). The other side of the oil delivery housing (31) adjacent to the oil inlet pipe (34) is opened, and the opening is used to connect the oil delivery chamber (311) and the inner groove (316), and a second sealing element (314) is elastically installed through a second elastic element (315). The lower end face of the second sealing element (314) is in contact with the outer surface of the second diaphragm (214) to maintain the dynamic sealing of the oil delivery chamber (311) during the reciprocating motion of the diaphragm.

7. A fuel pump assembly for a new energy hybrid vehicle with a pressure relief valve according to claim 6, characterized in that, A positioning frame (32) is fixedly installed inside the oil delivery housing (31). The positioning frame (32) is connected to the oil delivery housing (31) by positioning bolts (321) and is used to guide and support the movement of the seal.

8. A fuel pump assembly for a new energy hybrid vehicle with a pressure relief valve according to claim 2, characterized in that, The drive shaft (141) is connected to the drive cam (12) by a key, and the lifting block (13) is connected to the drive cam (12) by a rotating pair, which is used to ensure smooth power transmission and reduce motion friction resistance.

9. A fuel pump assembly for a new energy hybrid vehicle with a pressure relief valve according to claim 5, characterized in that, The oil inlet connector (341) and oil outlet connector (331) adopt a quick-connect interface structure to achieve quick disassembly and sealing connection of the pipeline.

10. A fuel pump assembly for a new energy hybrid vehicle with a pressure relief valve according to claim 1, characterized in that, The corrugated connecting pipe (43) is a metal braided hose structure, which is used to provide axial and radial elastic deformation capabilities to accommodate vibration displacement.

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