CN107131075B - Straight-through piezoelectric type internal guide gas injection valve with floating valve seat - Google Patents

Abstract

The invention aims to provide a piezoelectric type internal guide gas injection valve with a through type floating valve seat, which realizes the reverse leakage function caused by unbalanced internal and external pressure of the gas injection valve through a floating valve seat structure, and ensures the working reliability of the gas injection valve; the air inlet and the flow guiding process are realized through the straight-through structure and the flow guiding cavity structure; the control of the valve core and the air path are realized through the control of the piezoelectric actuator, and the air injection function is realized; the inner guide structure is matched with the pressure balance hole and the pressure balance groove, so that the perpendicularity of the valve core is ensured, the stable work and the reliable work of air flow are realized, and the high response speed is realized; the high flow is realized by the mixed air inlet mode of direct air inlet of the axial main air groove and air inlet of the circumferential air-filling holes, the air injection efficiency of the engine is effectively improved, the air flow interference can be avoided, and the stability of the air path is realized; the surface sealing and high reliability of the gas injection valve are realized through the multi-channel annular band structure between the valve core and the valve seat.

Description

Straight-through piezoelectric type internal guide gas injection valve with floating valve seat

Technical Field

The invention relates to a gas injection valve, in particular to a gas injection valve of a gas system of a natural gas engine.

Background

With the increasing stricter of emission regulations of ships and the continuous rising of fuel prices, gas engines and dual-fuel engines are increasingly important in the international market place. The fuel injection system is used as a key component of a gas engine and a dual-fuel engine, and the performance of the fuel injection system directly influences the dynamic property and the emission property of the engine. The gas injection valve is one of core parts of the gas engine with gas fuel electric control multi-point injection and comprises a dual-fuel engine, can realize the timing and quantitative stage gas supply and gas inlet layering of each cylinder, and has very important influence on the dynamic property and the emission property of the gas engine or the dual-fuel engine. Under the condition of severe engine working conditions, the injection valve is easy to generate reverse leakage. At the same time, in order to achieve more flexible jet control. Therefore, it is necessary to design an injection valve having a reverse leakage preventing function and a variable lift. Meanwhile, a high-flow gas injection valve with high response speed, high control precision and good reliability needs to be developed, so that the circulation capacity of the high-flow gas injection valve can meet the normal working requirement of a natural gas engine in a high-load state.

Disclosure of Invention

The invention aims to provide a piezoelectric type internal guide gas injection valve with a floating valve seat, which has the advantages of high response speed, stable gas injection, high reliability and reverse leakage prevention function.

The purpose of the invention is realized in the following way:

the invention relates to a piezoelectric internal guide gas injection valve with a straight-through type floating valve seat, which is characterized in that: comprises a valve body, a floating valve seat, a piezoelectric crystal, a control valve rod, a hydraulic amplifier, a baffle plate and a valve core assembly, wherein a fixed block is fixed above the inner part of the valve body, a straight groove is formed in the middle of the fixed block, the piezoelectric crystal is arranged in the straight groove, the middle of the valve body is provided with the baffle plate, the hydraulic amplifier is arranged above the baffle plate, the valve core assembly is arranged below the baffle plate, the baffle plate is respectively provided with a through hole and a vent hole, the hydraulic amplifier comprises a large piston, a small piston and a sleeve, the sleeve is arranged on the baffle plate, the end part of the upper end of the sleeve is provided with a thick outlet, the inner side of the end part of the upper end of the sleeve is provided with a thin outlet, the large piston is arranged in the thick outlet, a large piston supporting spring is arranged between the flange of the large piston and the sleeve, a small piston supporting spring is arranged between the flange of the small piston and the sleeve, hydraulic oil is filled in the sleeve below the large piston and the small piston, the valve core assembly comprises an armature, a spring seat, a bottom plate, a valve core, the armature, the bottom plate and the valve core are arranged from top to bottom and are simultaneously connected together through fastening bolts, the spring seat is positioned outside the armature and forms an annular groove with the armature, the lower surface of the partition plate is provided with the annular groove, two ends of a main reset spring are respectively arranged in the annular groove of the partition plate and the annular groove of the spring seat, the guide pin is fixed with the armature, a pressure balance hole is arranged in the guide pin, a pressure balance groove is arranged on the bottom plate, the valve core is of a hollow structure, and the pressure balance hole, the pressure balance groove is communicated with the hollow part of the valve core, the valve core is provided with a sealing ring belt, and the sealing ring belt forms a ring cavity; the floating valve seat comprises a guide base and a valve seat, wherein the guide base is fixed below the valve body, the valve seat is positioned below the valve core, a T-shaped structure is arranged on the inner ring of the guide base, the outer ring of the valve seat is arranged in the guide base through the T-shaped structure matched with the outer ring of the valve seat, two ends of a valve seat reset spring are respectively fixed on the valve seat and the valve core, an air outlet ring belt is arranged on the valve seat, the air outlet ring belt is positioned below the annular cavity, and an air outlet is arranged below the air outlet ring belt.

The invention may further include:

1. the double air leakage preventing structure is arranged between the valve seat and the guide base, the deformable sealing ring is arranged above the joint of the valve seat and the guide base, the pressing gasket is additionally arranged above the inner edge of the deformable sealing ring, the two layers of sealing rubber rings are arranged at the joint of the T-shaped structure of the valve seat and the guide base, and the elastic gasket is arranged at the joint of the T-shaped structure of the valve seat and the guide base.

2. An air inlet is formed between the upper part of the fixed block and the valve body, a flow guiding cavity is formed below the air inlet, and the flow guiding cavity is communicated with a space below the partition plate through an air vent;

the gas flows into the valve body vertically from the gas inlet, flows into the valve body along the flow guide cavity, is filled in the valve body, after the piezoelectric crystal is electrified, the valve core moves upwards to be separated from the surface of the valve seat, the gas circuit is opened, the gas valve is opened, the gas flows in a mixed gas inlet mode of the axial main gas groove and the circumferential gas filling hole, passes through the annular cavity, and flows out vertically from the gas outlet; the piezoelectric crystal is powered off, under the action of the main reset spring, the armature drives the valve core to move downwards until the surface of the valve core is attached to the surface of the valve seat, the valve core is restored to the initial position, the gas circuit is closed, and the gas valve is closed.

The invention has the advantages that: the invention adopts a structure with the floating valve seat, can effectively prevent the reverse leakage of the gas injection valve, has the function of shock absorption, and ensures the working reliability and safety of the gas injection valve; according to the invention, the pressure balance hole is formed in the center of the guide pin, and a certain number of pressure balance grooves are formed in the bottom plate, so that the armature is prevented from being subjected to axial force, the pressure of an inner gas circuit and an outer gas circuit at the armature is more easily balanced, and the response speed of the armature is improved; according to the invention, the four ribs of the valve core are provided with the circumferential air supplementing holes, so that the flow area is increased, the valve core quality is reduced, and the reliability is improved. The flow guide cone angle with a certain angle is arranged at the circumferential air filling hole of the valve core, so that the flow loss is reduced, and the flow coefficient is increased. The invention adopts a mixed air inlet mode of directly air inlet of the axial main air groove and air inlet of the circumferential air-filling holes, increases the air inlet flow coefficient, increases the air inlet amount, can avoid air flow interference and ensures that the air paths reach balance. The jet efficiency of the engine is effectively improved.

Drawings

FIG. 1 is a schematic diagram of the structure of the present invention;

FIG. 2 is a schematic view of a valve core assembly according to the present invention;

FIG. 3 is a schematic diagram of the gas path of the present invention;

FIG. 4 is a top view of the valve core structure;

FIG. 5 is a three-dimensional block diagram of a valve core structure;

FIG. 6 is an enlarged view of a floating valve seat structure;

FIG. 7 is a floating valve seat force diagram.

Detailed Description

The invention is described in more detail below, by way of example, with reference to the accompanying drawings:

referring to fig. 1-7, fig. 1 is a schematic diagram of the overall structure of the straight-through piezoelectric internal guide gas injection valve with a floating valve seat, which comprises four parts of a valve body 1, a piezoelectric actuator 3, a valve core assembly 15 and a floating valve seat 17. The piezoelectric actuator 3 is connected with the valve body 1 through upper threads. A valve core assembly 15 and a floating valve seat 17 are sequentially arranged below the piezoelectric actuator from top to bottom.

The piezoelectric actuator 3 consists of a piezoelectric crystal 2, a control valve rod 4, a hydraulic amplifier and an auxiliary reset spring 9, wherein the hydraulic amplifier consists of a large piston 5, a large piston supporting spring 6, a small piston 10, a small piston supporting spring 11 and a sleeve 8, the hydraulic amplifier is arranged above a baffle 13 on a valve body, the sleeve 8 is filled with fuel oil with certain pressure, and sealing rings 7 are arranged on the matching surfaces among the large piston 5, the small piston 10 and the sleeve 8; a control valve rod 4 is arranged below the piezoelectric crystal 2, the lower surface of the control valve rod 4 is contacted with the upper surface of a large piston 5 in the hydraulic amplifier, four large pistons and four small pistons in the hydraulic amplifier are symmetrically arranged, the piezoelectric crystal 2, the control valve rod 4 and the large piston 5 are tightly attached together under the action of a large piston supporting spring 6, a small piston 10 in the hydraulic amplifier is tightly attached to the lower surface of a guide pin 18 by utilizing a small piston supporting spring 11, and an auxiliary reset spring 4 is arranged on the upper surface of the guide pin 18.

Fig. 2 shows a valve core assembly 15 mainly comprising a guide pin 9, an armature 19, a spring seat 20, a fastening bolt 27, a gasket 25, a bottom plate 21 and a valve core 22. The method is characterized in that: the armature 19, the spacer 25, the base plate 21 and the valve core 22 are linked together by a fastening bolt 27, and the spring seat 20 is mounted on the base plate 21. The center of the guide pin 9 is provided with a pressure balance hole 24, the bottom plate 21 is provided with a certain number of pressure balance grooves 26, so that the armature 19 is prevented from being subjected to axial force, the internal and external air path pressures at the armature 19 are more easily balanced, and the response speed of the armature 19 is improved; the guide pin 9 is screwed to the armature 19. The main return spring 14 is located between the diaphragm 5 and the spring seat 20, and the auxiliary return spring 8 is located between the guide pin 9 and the control valve stem 4. After the piezoelectric crystal 2 is electrified, the piezoelectric crystal 2 is excited by current to stretch, so that the control valve rod 4 moves downwards, the large piston 5 on the hydraulic amplifier moves downwards along with the control valve rod, the liquid pressure in the sleeve 8 in the hydraulic amplifier is increased, the small piston on the hydraulic amplifier moves upwards under the action of the liquid pressure, the guide pin 18 steadily moves upwards after receiving the upward acting force of the four small pistons 10, the guide pin 18 serves as a part of the valve core assembly 15, the valve core assembly 15 integrally moves upwards along with the guide pin, the axial movement and the circumferential positioning of the armature 19 are controlled by the cooperation between the guide pin 9 and the partition plate 5 in the whole moving process until the upper surface of the spring seat 20 is contacted with the lower surface of the partition plate 5, the armature 19 is maintained at the position for a period of time, the piezoelectric crystal 2 is cut off, the piezoelectric crystal 2 starts to shorten, the large piston 5 starts to move upwards under the action of the large piston supporting spring 6, the guide pin 18 starts to move downwards along with the auxiliary piston under the action of the main reset spring, the small piston 10 and the whole valve core assembly 15 move downwards until the small piston assembly 15 returns to the initial position, the corresponding to the small piston assembly is closed, and the valve core assembly returns to the initial position.

The four ribs 29 of the valve core 22 are respectively provided with 2 circumferential air supplementing holes 33, so that the response speed is improved, the flow area is increased, the quality is reduced, and the reliability is improved. The circumferential air-filling holes 33 are provided with a flow-guiding cone angle with a certain angle, so that the flow loss is reduced, and the flow coefficient is increased. The mixed air inlet mode of direct air inlet of the axial main air groove 35 and air inlet of the circumferential air-filling holes 33 is adopted, the air inlet flow coefficient is increased, the air inlet amount is increased, and meanwhile, air flow interference can be avoided, so that the air path reaches balance. The air outlet ring belt 16 is adopted between the valve core 22 and the valve seat 39, the surface is sealed, the pressure is stabilized and balanced, the impact can be reduced by the wider ring belt area, and the reliability is improved.

The gas path is shown in fig. 4, gas flows vertically into the valve body 1 from the gas inlet 30, flows into the valve body 1 along the flow guide cavity 31, and after the piezoelectric crystal 2 is electrified, the gas valve is opened, the gas flows in a mixed gas inlet mode of the axial main gas groove 35 and the circumferential gas-filling holes 33, passes through the annular cavity 32, and finally flows out vertically from the gas outlet 34; the piezoelectric crystal 2 is powered off and the gas valve is closed.

As shown in fig. 3, the present invention employs a floating valve seat 17 structure in order to prevent reverse leakage of fuel gas and to improve reliability and safety of the fuel gas injection valve. The floating valve seat 17 can lock the gas valve when the external pressure and the internal pressure of the gas valve are high, so that the reverse leakage of the gas is effectively prevented. The floating valve seat 17 is composed of 7 parts: guide base 37, valve seat 39, and valve seat return spring 43, packing 38, pressing washer 24, deformable seal 41, elastic washer 42. The guide base 37 is fixed to the valve body 1 by bolts, and the valve seat 39 is mounted on the guide base 37. The inner ring of the guide base 37 is provided with a T-shaped structure which is matched with the T-shaped structure of the outer ring of the valve seat 39. The valve seat return spring 43 is fixed to the valve seat 39 and the valve element 22 at both ends, respectively, and maintains a certain preload.

In order to prevent air leakage between the valve seat 39 and the guide base 37, a dual air leakage preventing structure is additionally arranged between the valve seat 39 and the guide base 37, a deformable sealing ring 41 is arranged above the joint of the valve seat 39 and the guide base 37, the outer edge of the deformable sealing ring 41 is tightly pressed in the mounting groove on the guide base 37 and the valve body 1, and the outer edge is fixed by the pretightening force of the bolt between the guide base 37 and the valve body 1. The pressing washer 24 is additionally arranged above the inner edge of the deformable sealing ring 41 and is fixed on the valve seat 39 through the screw 40, and the pressing washer 24 ensures uniform stress and enhances tightness. The deformable sealing ring 41 is made of deformable soft plastic, so that the movement of the valve seat 39 is not affected. The second sealing is that two layers of sealing rubber rings 38 are additionally arranged at the T-shaped connection part of the valve seat 39 and the guide base 37, so that the sealing performance is further enhanced. A layer of elastic washer 42 is additionally arranged at the T-shaped connection part between the valve seat 39 and the guide base 37, so that vibration impact force during contact is reduced, and the shock absorption effect is achieved. The reliability of the gas valve is effectively increased.

The valve seat 39 is acted upon by the valve seat return spring 43 elastic force F4, the gas valve external gas pressures F1 and F2, the gas valve internal gas pressure F3, and the valve spool 22 pressing force. The valve core 22 is acted on by the elastic force of the main return spring 14. When the gas pressure below the gas valve is greater than the gas pressure inside the gas valve, the gas pressure outside the gas valve F1 and F2 respectively act on the lower part of the valve seat 39 and the position of the gas outlet ring belt 16, the contact area below the valve seat 39 is far greater than that of the gas outlet ring belt 16, so that F1 is far greater than F2, and before the external gas pressure expands to cause the upward movement of the valve core 22, the external gas pressure overcomes the spring pretightening force of the main return spring 14, and the valve seat 39 moves upward together with the valve core 22. The valve seat 39 moves upward until the spring seat 20 contacts the diaphragm 13. At this time, even if the piezoelectric crystal 2 is energized, the valve element 22 cannot move upward, and the gas valve cannot be opened. The gas valve is locked.

When the gas pressure inside and outside the gas valve is restored to normal, the valve seat 39 moves downward to return to the original position by the valve seat return spring 43. If the piezoelectric crystal 2 is electrified at this time, the valve core 22 still keeps still, and the gas valve is normally opened. When the gas valve is to be closed, the piezoelectric crystal 2 is powered off, the valve core 22 moves downwards under the action of the main return spring 14, and the gas valve is closed. If the piezo-electric crystal 2 is not energized at this time, the valve seat 39 moves back down with the valve spool 22 under the action of the main return spring 14, and the gas valve remains closed. When the gas valve is to be opened, the piezoelectric crystal 2 is electrified, the valve core 22 moves upwards, and the gas valve is normally opened.

According to the working process, the through-type internal guide gas injection valve with the floating valve seat 17 adopts the structure with the floating valve seat 17, so that the reverse leakage of the gas injection valve can be effectively prevented under the condition that the internal and external air pressures of the injection valve are abnormal, the gas injection valve has a damping function, and the working reliability and safety of the gas injection valve are ensured; meanwhile, the pressure balance hole 24 is formed in the center of the guide pin 9, a certain number of pressure balance grooves 26 are formed in the bottom plate 21, so that the armature 19 is prevented from being subjected to axial force, the internal and external air path pressure at the armature 19 is more easily balanced, and the response speed of the armature 19 is improved; the four ribs 29 of the valve core 22 are provided with circumferential air supplementing holes 33, so that the flow area is increased, the quality of the valve core 22 is reduced, and the reliability is improved. The circumferential air-filling hole 33 of the valve core 22 is provided with a flow-guiding cone angle with a certain angle, so that the flow loss is reduced, and the flow coefficient is increased. The invention adopts a mixed air inlet mode of directly air inlet of the axial main air groove 35 and air inlet of the circumferential air-filling holes 33, increases the air inlet flow coefficient, increases the air inlet amount, can avoid air flow interference and ensures that the air paths reach balance. The jet efficiency of the engine is effectively improved.

The technical scheme of the invention is as follows: a piezoelectric internal guide gas injection valve with a through type floating valve seat is composed of a valve body, a piezoelectric actuator, a valve core assembly and a floating valve seat. The piezoelectric actuator is connected with the valve body through threads above the piezoelectric actuator. The piezoelectric actuator consists of a piezoelectric crystal, a control valve rod, a hydraulic amplifier and an auxiliary reset spring, wherein the hydraulic amplifier consists of a large piston, a large piston supporting spring, a small piston supporting spring and a sleeve, the hydraulic amplifier is arranged above a partition plate on a valve body, fuel oil with certain pressure is fully distributed in the sleeve, and sealing rings 7 are arranged on the matching surfaces among the large piston, the small piston and the sleeve; the lower surface of the control valve rod is contacted with the upper surface of a large piston in the hydraulic amplifier, the four large pistons and the four small pistons in the hydraulic amplifier are symmetrically arranged, the piezoelectric crystal, the control valve rod and the large piston are tightly attached together under the action of a large piston supporting spring, the small piston in the hydraulic amplifier is tightly attached to the lower surface of a guide pin by utilizing a small piston supporting spring, and an auxiliary reset spring is arranged on the surface of the guide pin. A valve core assembly and a floating valve seat are sequentially arranged below the piezoelectric actuator from top to bottom. The valve core assembly mainly comprises an armature, a spring seat, a fastening bolt, a gasket, a bottom plate and a valve core. The armature, the gasket, the bottom plate and the valve core are linked together through a fastening bolt, the spring seat is arranged on the bottom plate, and a certain number of pressure balance grooves are formed in the bottom plate. The main reset spring is positioned between the partition plate and the spring seat, and the center of the guide pin is provided with a pressure balance hole. The ribs of the valve core are respectively provided with circumferential air-filling holes. Three air outlet annular zones are adopted between the valve core and the valve seat, the surfaces are sealed, the pressure is stabilized and balanced, and the valve core and the valve seat have wider annular zone areas. The floating valve seat consists of a guide base, a valve seat reset spring, a sealing rubber ring, a pressing gasket, a deformable sealing ring and an elastic gasket. The guide base is fixed on the valve body through bolts, and the valve seat is installed on the guide base. The guide base inner ring is provided with a T-shaped structure which is matched with the T-shaped structure of the valve seat outer ring. The two ends of the valve seat reset spring are respectively fixed on the valve seat and the valve core, and a certain pretightening force is maintained. The double air leakage preventing structure is additionally arranged between the valve seat and the guide base, the deformable sealing ring is arranged above the joint of the valve seat and the guide base, the outer edge of the deformable sealing ring is tightly pressed in the mounting groove on the guide base and the valve body, and the deformable sealing ring is fixed by the pretightening force of the bolt between the guide base and the valve body. The upper part of the inner edge of the deformable sealing ring is additionally provided with a pressing gasket which is fixed on the valve seat through a screw. The deformable sealing ring is made of deformable soft plastic, so that the movement of the valve seat is not influenced. The second double seal is that two layers of sealing rubber rings are additionally arranged at the T-shaped connection part of the valve seat and the guide base.

Claims (3)

1. A piezoelectric internal guiding gas injection valve with a straight-through type floating valve seat is characterized in that: comprises a valve body, a floating valve seat, a piezoelectric crystal, a control valve rod, a hydraulic amplifier, a baffle plate and a valve core assembly, wherein a fixed block is fixed above the inner part of the valve body, a straight groove is formed in the middle of the fixed block, the piezoelectric crystal is arranged in the straight groove, the middle of the valve body is provided with the baffle plate, the hydraulic amplifier is arranged above the baffle plate, the valve core assembly is arranged below the baffle plate, the baffle plate is respectively provided with a through hole and a vent hole, the hydraulic amplifier comprises a large piston, a small piston and a sleeve, the sleeve is arranged on the baffle plate, the end part of the upper end of the sleeve is provided with a thick outlet, the inner side of the end part of the upper end of the sleeve is provided with a thin outlet, the large piston is arranged in the thick outlet, a large piston supporting spring is arranged between the flange of the large piston and the sleeve, a small piston supporting spring is arranged between the flange of the small piston and the sleeve, hydraulic oil is filled in the sleeve below the large piston and the small piston, the valve core assembly comprises an armature, a spring seat, a bottom plate, a valve core, the armature, the bottom plate and the valve core are arranged from top to bottom and are simultaneously connected together through fastening bolts, the spring seat is positioned outside the armature and forms an annular groove with the armature, the lower surface of the partition plate is provided with the annular groove, two ends of a main reset spring are respectively arranged in the annular groove of the partition plate and the annular groove of the spring seat, the guide pin is fixed with the armature, a pressure balance hole is arranged in the guide pin, a pressure balance groove is arranged on the bottom plate, the valve core is of a hollow structure, and the pressure balance hole, the pressure balance groove is communicated with the hollow part of the valve core, the valve core is provided with a sealing ring belt, and the sealing ring belt forms a ring cavity; the floating valve seat comprises a guide base and a valve seat, wherein the guide base is fixed below the valve body, the valve seat is positioned below the valve core, a T-shaped structure is arranged on the inner ring of the guide base, the outer ring of the valve seat is arranged in the guide base through the T-shaped structure matched with the outer ring of the valve seat, two ends of a valve seat reset spring are respectively fixed on the valve seat and the valve core, an air outlet ring belt is arranged on the valve seat, the air outlet ring belt is positioned below the annular cavity, and an air outlet is arranged below the air outlet ring belt.

2. A straight-through piezoelectric internal pilot gas injection valve with a floating valve seat as defined in claim 1, wherein: the double air leakage preventing structure is arranged between the valve seat and the guide base, the deformable sealing ring is arranged above the joint of the valve seat and the guide base, the pressing gasket is additionally arranged above the inner edge of the deformable sealing ring, the two layers of sealing rubber rings are arranged at the joint of the T-shaped structure of the valve seat and the guide base, and the elastic gasket is arranged at the joint of the T-shaped structure of the valve seat and the guide base.

3. A straight-through piezoelectric internal pilot gas injection valve with a floating valve seat as claimed in claim 1 or 2, characterized in that: an air inlet is formed between the upper part of the fixed block and the valve body, a flow guiding cavity is formed below the air inlet, and the flow guiding cavity is communicated with a space below the partition plate through an air vent;

the gas flows into the valve body vertically from the gas inlet, flows into the valve body along the flow guide cavity, is filled in the valve body, after the piezoelectric crystal is electrified, the valve core moves upwards to be separated from the surface of the valve seat, the gas circuit is opened, the gas valve is opened, the gas flows in a mixed gas inlet mode of the axial main gas groove and the circumferential gas filling hole, passes through the annular cavity, and flows out vertically from the gas outlet; the piezoelectric crystal is powered off, under the action of the main reset spring, the armature drives the valve core to move downwards until the surface of the valve core is attached to the surface of the valve seat, the valve core is restored to the initial position, the gas circuit is closed, and the gas valve is closed.

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