Marine dual fuel engine methanol injector

Abstract

The application discloses a methanol injector for a marine dual-fuel engine, which comprises an upper end cover, a pressure regulating rod, an upper valve body, a needle valve seat, a lower screw sleeve, an upper push rod, a lower needle valve, an electromagnetic coil, a pressure regulating spring, an upper spring seat and an upper push rod and lower needle valve rotating device comprising a clutch mechanism and a rotating mechanism, the clutch mechanism comprises an upper end surface ratchet, a lower end surface ratchet and an upper end surface ratchet reset spring, the upper end surface ratchet is in clearance fit with the lower end of the pressure regulating rod, the lower end surface ratchet is fixed on the top end of the lower needle valve, a plane bearing is supported on the upper end of the upper push rod, the pressure regulating spring is supported between the upper spring seat and the plane bearing, the upper end surface ratchet reset spring is supported between the lower side surface of the upper spring seat and the upper side surface of the plane bearing, and the rotating mechanism comprises a pair of spiral grooves, a cylindrical pin and a copper sleeve. The application is simple to operate and convenient for periodical maintenance. The service life of the lower needle valve and the needle valve seat coupling piece is significantly prolonged, the use cost is reduced, and the reliability of the application is improved.

Description

TECHNICAL FIELD

[0001] The application relates to a methanol fuel injector of a marine dual-fuel engine, in particular to a methanol injector capable of making the wear of a sealing cone surface more uniform, and belongs to the technical field of marine engines. BACKGROUND

[0002] With the increasingly stringent global ship emission regulations of the International Maritime Organization, the use of methanol fuel, which is easy to store, low in emission and high in energy efficiency, by a marine dual-fuel engine can not only reduce the dependence of a diesel engine on petroleum energy, but also greatly reduce pollutant emission.

[0003] The methanol fuel is different from diesel fuel and gasoline fuel, and has a certain corrosiveness to metal materials, so that the needle valve material has a higher requirement. At present, the methanol injector has the problems of low service life of the needle valve and the needle valve seat and poor sealing, and the main reasons are as follows:

[0004] 1) Since methanol has strong corrosiveness to metal and the impact on the contact area of the needle valve and the needle valve seat is large, the contact surface of the needle valve and the needle valve seat of the traditional methanol injector is fixed and does not change, and after long-term use, the slight deformation of the needle valve and the needle valve seat is more likely to aggravate the corrosion degree of methanol to the needle valve and the needle valve seat, so that the service life of the methanol injector is significantly shortened.

[0005] 2) Due to the impurities of the methanol fuel or the surface wear between the needle valve and the needle valve seat, the sealing property of the coupling of the needle valve and the needle valve seat is reduced, and under the action of high impact, the surface material of the needle valve head is separated and peeled off, which seriously affects the sealing property of the precision coupling and causes the problems of inaccurate injection and oil dripping of the injector, and the harm caused by the problems is much higher than that of the traditional diesel injector.

[0006] 3) The high-speed movement impact force of the needle valve is large, and under the action of high temperature and high pressure, the contact stress fatigue phenomenon of the contact surface of the needle valve and the needle valve body is easily caused, and finally the surface deformation is caused, so that the methanol injector cannot work normally.

[0007] 4) After long-term work of the needle valve, the sealing surface of the needle valve and the needle valve seat is unevenly worn, heat accumulation occurs at different positions of the needle valve, deformation occurs, the adhesive wear of the needle valve is accelerated, cracks and contact point tears are generated on the metal surface, and the sealing property of the precision fitting surface of the needle valve and the needle valve seat is seriously reduced. SUMMARY

[0008] The application aims to provide a methanol injector of a marine dual-fuel engine with a rotatable needle valve, improve the working reliability of the methanol injector, and prolong the service life thereof.

[0009] The application is implemented by the following technical scheme:

[0010] A methanol injector of a dual-fuel engine for a ship comprises an upper end cover, a pressure regulating rod, an upper valve body, a needle valve seat, a lower screw sleeve, an upper valve rod, a lower needle valve, an electromagnetic coil, a pressure regulating spring, an upper spring seat, and an upper valve rod and lower needle valve rotating device, the upper end cover is an inverted cylinder, the lower end of the upper end cover is fixed on the top end of the upper valve body by several fastening screws; the upper spring seat, the electromagnetic coil and the pressure regulating spring are located in the upper end cover, the pressure regulating spring is sleeved on the lower end of the pressure regulating rod and the upper end of the upper valve rod, the upper spring seat is located on the top end of the pressure regulating spring and is fixedly connected with the pressure regulating rod; the pressure regulating nut is screwed on the upper end thread of the pressure regulating rod penetrating through the upper end cover, the pressure regulating spring is located in the electromagnetic coil; the lower end of the upper valve body is threadedly connected with the upper end of the lower screw sleeve and is sealed by a radial sealing ring; the needle valve seat is embedded and fixed in the lower part of the lower screw sleeve, the lower end valve sleeve of the needle valve seat penetrates through the center of the bottom of the lower screw sleeve; the lower end of the pressure regulating rod is adjacent to the top end of the upper valve rod, the end face of the lower end of the upper valve body abuts against the end face of the upper end of the needle valve seat, and they are positioned by a pair of guide pins; the upper valve rod is threadedly connected with the top end of the lower needle valve in the stepped center hole of the needle valve seat after penetrating through the center hole of the upper valve body, the lower end tapered tip of the lower needle valve abuts against the tapered counterbore in the lower end of the needle valve seat after penetrating through the methanol storage cavity in the middle part of the needle valve seat, and blocks the several methanol injection holes in the bottom of the lower end valve sleeve; one end of the methanol inlet connector is screwed into the upper end of the upper valve body on one side and communicates with the upper side of the methanol storage cavity through the conveying channel, and the lower side of the methanol storage cavity communicates with the upper end of the stepped center hole of the needle valve seat; the upper valve rod and lower needle valve rotating device are arranged in the upper end cover, the upper valve rod and lower needle valve rotating device comprises a clutch mechanism and a rotating mechanism, the clutch mechanism comprises an upper end face ratchet, a lower end face ratchet and an upper end face ratchet return spring, the upper end face ratchet is gap-fitted with the lower end of the pressure regulating rod, the lower end face ratchet is fixed on the top end of the upper valve rod, a plain bearing is supported on the upper end of the upper valve rod, and the pressure regulating spring is supported between the upper spring seat and the plain bearing; the upper end face ratchet return spring sleeved on the lower end of the pressure regulating rod is located in the pressure regulating spring and is supported between the lower side of the upper spring seat and the upper side of the upper end face ratchet; the rotating mechanism is arranged between the lower end of the outer circumferential surface of the pressure regulating rod and the inner hole of the upper end face ratchet.

[0011] The purpose of the application can also be further achieved by the following technical measures.

[0012] Further, the rotating mechanism comprises a pair of helical grooves, guide pins and copper sleeves, the helical grooves are symmetrically arranged on the lower end of the outer circumferential surface of the pressure regulating rod, and one end of the guide pin is respectively fixed in the inner hole of the upper end face ratchet; the inner hole of the copper sleeve is respectively embedded on the other end of the guide pin, the outer circle of the copper sleeve is embedded in the helical groove, the inner hole of the copper sleeve and the other end of the guide pin, and the outer circle of the copper sleeve and the helical groove are all gap-fitted.

[0013] Further, the material of the upper end face ratchet is iron-nickel alloy.

[0014] Further, the helical pitch angle of the helical groove is greater than or equal to 65 degrees.

[0015] Further, the upper valve rod upper end is supported in the upper valve body central hole and is in clearance fit with the upper valve body central hole; the lower needle valve upper end passes through the needle valve seat stepped central hole and is in clearance fit with the large end hole of the upper part of the needle valve seat stepped central hole, and the ratio of the diameter D1 of the lower needle valve lower end to the diameter D2 of the small end hole of the lower part of the needle valve seat stepped central hole is D1 / D2=0.77-0.83.

[0016] Further, the upper valve rod outer circumferential surface and the lower needle valve outer circumferential surface are both chrome-plated, and the surface hardness of the upper valve rod outer circumferential surface and the surface hardness of the lower needle valve outer circumferential surface are both HRC>=50.

[0017] The clutch mechanism and the rotating mechanism of the present application make the methanol injector have two modes of direct injection and rotary injection. In the direct injection mode, the electromagnetic coil is electrified, the upper end surface ratchet is magnetized and quickly moves upward under the action of the electromagnetic field, and the upper end surface ratchet return spring is compressed at the same time. At this time, the high-pressure methanol liquid output by the high-pressure injection pump passes through the methanol inlet joint, the conveying hole, the methanol storage cavity and the needle valve seat stepped central hole in turn. The methanol liquid pressure in the methanol storage cavity is greater than the pre-tightening pressure of the pressure regulating spring. The lower needle valve drives the upper valve rod to quickly move upward. The distance between the upper end surface ratchet and the lower end surface ratchet is increased. The clutch mechanism and the rotating mechanism are both inaction, and the direct injection function of the methanol injector is realized.

[0018] When the methanol injector has been operated for a long time, the wear of the lower needle valve and the needle valve seat is increased, and the impurities in the conical counterbore are increased, the rotary injection mode can be converted. The electromagnetic coil is de-energized, the magnetic field force quickly disappears, the upper end surface ratchet quickly demagnetizes, and the upper end surface ratchet reversely rotates and moves downward under the elastic force of the upper end surface ratchet return spring and the coupling action of the pair of guide pins and the pair of spiral grooves of the pressure regulating rod. At this time, the methanol liquid pressure in the methanol storage cavity is greater than the pre-tightening pressure of the pressure regulating spring. The lower needle valve drives the upper valve rod to quickly move upward, so that the lower end surface ratchet and the upper end surface ratchet quickly mesh. The meshed upper end surface ratchet and lower end surface ratchet continue to move upward under the elastic force of the upper end surface ratchet return spring, and rotate around the pressure regulating rod center under the coupling action of the pair of guide pins of the upper end surface ratchet and the pair of spiral grooves of the pressure regulating rod, so as to realize the rotation of the lower needle valve.

[0019] When the methanol fuel is sprayed out from the methanol injection hole, the liquid pressure of the methanol in the methanol storage cavity is lower than the pre-tightening pressure of the pressure regulating spring, under the action of the elastic force of the pressure regulating spring, the lower end surface ratchet drives the upper valve rod and the lower needle valve to directly drop without rotating, in multiple working cycles, the relative contact position of the lower end tapered tip of the lower needle valve and the tapered counterbore of the lower end of the needle valve seat is constantly changed, so that the wear of the lower end tapered tip of the lower needle valve and the sealing tapered surface of the needle valve seat is more uniform, so that the good sealing of the lower needle valve and the needle valve seat needle valve precision coupling is realized, the point contact fatigue, pitting and pitting caused by individual points are prevented. At the same time, through the rotating movement of the lower needle valve, the lower needle valve and the upper valve rod can be uniformly heated at each position, and deformation caused by uneven heating of the two is avoided, which leads to different movements. The operation of the present application is simple, convenient for regular maintenance, prolongs the service life of the lower needle valve and the needle valve seat coupling, reduces the use cost, and improves the reliability of the present application.

[0020] The advantages and characteristics of the present application will be illustrated and explained by the following non-limiting description of preferred embodiments, which are given by way of example only, with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a structural schematic diagram of the present application;

[0022] Figure 2 is Figure 1 I part of the enlarged view;

[0023] Figure 3 is Figure 1 II part of the enlarged view;

[0024] Figure 4 is Figure 2 A-A section view of the enlarged view of the present application. DETAILED DESCRIPTION

[0025] The present application will be further described below in conjunction with the drawings and examples.

[0026] In the description of the present application, the terms indicating the orientation or positional relationship such as "upper", "lower", "left", "right", "inner", "outer" and the like are based on the orientation or positional relationship shown in the drawings, and do not indicate or imply that the device referred to must have a particular orientation.

[0027] As Figures 1-4As shown, the present application comprises an upper end cover 1, a pressure regulating rod 2, an upper valve body 3, a needle valve seat 4, a lower screw sleeve 5, an upper valve rod 6, a lower needle valve 7, an electromagnetic coil 8, a pressure regulating spring 9, an upper spring seat 10, and an upper valve rod and lower needle valve rotating device 20. The upper end cover 1 is an inverted cylinder, and the lower end of the upper end cover 1 is fixed on the top end of the upper valve body 3 by several fastening screws 11. The upper spring seat 10, the electromagnetic coil 8, and the pressure regulating spring 9 are all located inside the upper end cover 1. The pressure regulating spring 9 is sleeved on the lower end of the pressure regulating rod 2 and the upper end of the upper valve rod 6, and the upper spring seat 10 is located on the top end of the pressure regulating spring 9 and is fixedly connected with the pressure regulating rod 2 by a fastening screw 21. A pressure regulating nut 22 is screwed on the upper end of the pressure regulating rod 2 that penetrates through the upper end cover 1. By turning the pressure regulating nut 22, the pre-tightening force of the upper spring seat 10 on the pressure regulating spring 9 can be changed, the moving resistance of the lower needle valve 7 can be changed, and thus the opening force of the lower needle valve 7 can be adjusted. The pressure regulating spring 9 is located inside the electromagnetic coil 8. The lower end of the upper valve body 3 is threadedly connected with the upper end of the lower screw sleeve 5 and is sealed by a radial sealing ring 51. The needle valve seat 4 is embedded and fixed in the lower part of the lower screw sleeve 5, and the lower end valve sleeve 41 of the needle valve seat 4 penetrates through the center of the bottom of the lower screw sleeve 5. The lower end of the pressure regulating rod 2 is adjacent to the top end of the upper valve rod 6, and the end face of the lower end of the upper valve body 3 abuts against the end face of the upper end of the needle valve seat 4, and they are positioned by a pair of guide pins 42. The upper valve rod 6 is threadedly connected with the top end of the lower needle valve 7 in the stepped center hole 43 of the needle valve seat after penetrating through the center hole 31 of the upper valve body, so as to improve the coaxiality of the transmission of the upper valve rod 6 and the lower needle valve 7. The lower end tapered tip 71 of the lower needle valve penetrates through the methanol storage cavity 44 in the middle part of the needle valve seat 4 and abuts against the tapered counterbore 45 at the lower end of the needle valve seat 4, so as to block the several methanol injection holes 411 at the bottom of the lower end valve sleeve 41. The right end of the methanol inlet joint 32 is screwed and fixed on the right side of the upper end of the upper valve body 3, and is communicated with the upper side of the methanol storage cavity 44 through the conveying channel 33, and the lower side of the methanol storage cavity 44 is communicated with the upper end of the stepped center hole 43 of the needle valve seat.

[0028] The upper valve rod and lower needle valve rotating device 20 is arranged in the upper end cover 1 and comprises a clutch mechanism 23 and a rotating mechanism 24. The clutch mechanism 23 comprises an upper end face ratchet wheel 231, a lower end face ratchet wheel 232, and an upper end face ratchet wheel reset spring 233. The upper end face ratchet wheel 231 is gap-fitted with the lower end of the pressure regulating rod 2. The lower end face ratchet wheel 232 is fixed on the top end of the upper valve rod 6 by a lower fastening screw 234. A plane bearing 235 is supported on the upper end of the upper valve rod 6. The pressure regulating spring 9 is supported between the upper spring seat 10 and the plane bearing 235. The upper end face ratchet wheel reset spring 236 sleeved on the lower end of the pressure regulating rod 2 is located inside the pressure regulating spring 9 and is supported between the lower side of the upper spring seat 10 and the upper side of the upper end face ratchet wheel 231.

[0029] The rotating mechanism 24 is arranged between the lower end of the outer circumferential surface of the pressure regulating rod 2 and the inner hole of the upper end face ratchet 231, and comprises a pair of helical grooves 241, guide pins 242 and copper sleeves 243. The helical grooves 241 are symmetrically arranged on the lower end of the outer circumferential surface of the pressure regulating rod 2, and the guide pins 242 are fixed on the inner hole of the upper end face ratchet 231 in a radial direction. The inner holes of the copper sleeves are respectively embedded on the other ends of the guide pins 242, the outer circles of the copper sleeves 243 are embedded in the helical grooves 241, the inner holes of the copper sleeves 243 are matched with the other ends of the guide pins 242, and the outer circles of the copper sleeves 243 are matched with the helical grooves 241. The helical grooves 241 have a helical angle α≥65°, which ensures that the upper end face ratchet 231 can be easily moved up and down without self-locking when it rotates in a forward or reverse direction, and the pressure regulating rod 2 will not rotate. The upper end face ratchet 231 drives the lower end face ratchet 232 engaged therewith to rotate slightly by 3-5°, so that the lower end tapered tip 71 of the lower needle valve 7 is uniformly ground with the tapered counterbore 45 of the lower end of the needle valve seat 4. The clearance matching between the inner holes of the copper sleeves 243 and the other ends of the guide pins 242 plays a role of reducing friction. The hardness of the copper sleeves 243 is lower than that of the helical grooves 241, which can avoid wearing the helical grooves 241.

[0030] The outer circumferential surface of the upper valve rod 6 and the outer circumferential surface of the lower needle valve 7 are both chrome-plated, which can effectively resist the corrosion of methanol fuel. The surface hardness of the outer circumferential surface of the upper valve rod 6 and the surface hardness of the outer circumferential surface of the lower needle valve 7 are both HRC≥50, which prolongs the service life of the upper valve rod 6 and the lower needle valve 7 as precision machined parts.

[0031] The lower end of the upper valve rod 6 is supported in the upper center hole 31 of the upper valve body and is clearance-fitted with the upper center hole 31 of the upper valve body. In this embodiment, the ratio of the diameter D1 of the lower end of the lower needle valve to the diameter D2 of the small end hole of the lower part of the stepped center hole 43 of the needle valve seat is D1 / D2=0.8. Such a structure allows the upper and lower ends of the upper valve rod 6 and the lower needle valve 7, which are integrally connected by threaded fixing, to be accurately positioned, while reducing the fitting length of the upper valve rod 6 and the upper valve body 3, and the lower needle valve 7 and the needle valve seat 4, thereby significantly reducing the manufacturing cost of the parts of the present application. The diameter D1 of the lower end of the lower needle valve is smaller than the diameter D2 of the small end hole of the lower part of the stepped center hole 43 of the needle valve seat, so that an annular cavity is formed between the small end hole of the lower part of the stepped center hole 43 and the outer edge of the lower end of the lower needle valve, which facilitates the upward thrust of the high-pressure formaldehyde liquid on the middle conical surface of the lower needle valve 7 to open the present application, thereby improving the opening sensitivity of the present application.

[0032] The material of the upper end surface ratchet wheel 231 is iron-nickel alloy, the strength of which is much higher than that of pure iron, and it has high coercive force. When the electromagnetic coil 8 is powered, the upper end surface ratchet wheel 231 made of iron-nickel alloy is quickly magnetized to compress the upper end surface ratchet return spring and move upward, so that the lower end surface ratchet wheel 232 cannot engage with the upper end surface ratchet wheel 231 after rising. When the electromagnetic coil 8 is de-energized, the residual magnetic field strength of the upper end surface ratchet wheel 231 immediately decreases to 0 and loses magnetism, so that the upper end surface ratchet wheel 231 quickly falls under the elastic force of the upper end surface ratchet return spring 236, thereby quickly engaging with the lower end surface ratchet wheel 232, and the reaction is very sensitive.

[0033] In addition to the above-mentioned embodiments, the present application can also have other implementation manners, and any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the protection scope required by the present application.

Claims

1. A methanol injector for a marine dual-fuel engine, comprising an upper end cover, a pressure regulating rod, an upper valve body, a needle valve seat, a lower threaded sleeve, an upper valve stem, a lower needle valve, an electromagnetic coil, a pressure regulating spring, and an upper spring seat. The upper end cover is inverted cylindrical, and its lower end is fixed to the top of the upper valve body by several fastening screws. The upper spring seat, the electromagnetic coil, and the pressure regulating spring are all located inside the upper end cover. The pressure regulating spring is sleeved on the lower end of the pressure regulating rod and the upper end of the upper valve stem. The upper spring seat is located on the top of the pressure regulating spring and is fixedly connected to the pressure regulating rod. The pressure regulating nut is screwed onto the upper thread of the pressure regulating rod that extends out of the upper end cover, and the pressure regulating spring is located inside the electromagnetic coil. The lower end of the upper valve body is threadedly connected to the upper end of the lower threaded sleeve and sealed by a radial sealing ring. The needle valve seat is embedded in... The valve is fixed in the lower part of the lower screw sleeve, and the lower end of the valve sleeve of the needle valve seat protrudes from the center of the bottom of the lower screw sleeve; the lower end of the pressure regulating rod is adjacent to the top of the upper valve rod, the lower end face of the upper valve body abuts against the upper end face of the needle valve seat, and is positioned by a pair of cylindrical pins; the upper valve rod passes through the center hole of the upper valve body and is connected to the top of the lower needle valve in the stepped center hole of the needle valve seat by a thread, and the lower end of the lower needle valve cone passes through the methanol storage cavity in the middle of the needle valve seat and abuts against the tapered countersunk hole at the lower end of the lower valve sleeve of the needle valve seat, blocking several methanol spray holes at the bottom of the lower valve sleeve; one end of the methanol inlet connector is screwed into and fixed on one side of the upper end of the upper valve body, and communicates with the upper side of the methanol storage cavity through the conveying channel, and the lower side of the methanol storage cavity communicates with the upper end of the stepped center hole of the needle valve seat; its characteristic is that... It also includes an upper valve stem and lower needle valve rotating device disposed within the upper end cover. The upper valve stem and lower needle valve rotating device includes a clutch mechanism and a rotating mechanism. The clutch mechanism includes an upper end face ratchet, a lower end face ratchet, and an upper end face ratchet return spring. The upper end face ratchet is clearance-fitted with the lower end of the pressure regulating rod. The lower end face ratchet is fixed on the top of the upper valve stem. A plane bearing supports the upper end of the upper valve stem. The pressure regulating spring is supported between the upper spring seat and the plane bearing. The upper end face ratchet return spring, which is sleeved on the lower end of the pressure regulating rod, is located inside the pressure regulating spring and is supported between the lower side of the upper spring seat and the upper side of the upper end face ratchet. The rotating mechanism is disposed between the lower end of the outer circumference of the pressure regulating rod and the inner hole of the upper end face ratchet. The rotating mechanism includes a pair of spiral grooves, guide pins and copper sleeves. The spiral grooves are symmetrically arranged on the lower end of the outer peripheral surface of the pressure regulating rod. One end of the guide pin is radially fixed in the inner hole of the ratchet on the upper end face. The inner hole of the copper sleeve is respectively embedded in the other end of the guide pin. The outer circle of the copper sleeve is embedded in the spiral groove. The inner hole of the copper sleeve and the other end of the guide pin, and the outer circle of the copper sleeve and the spiral groove are all clearance fits. The upper end of the upper valve stem is supported in the upper center hole of the upper valve body and is in clearance fit with the upper center hole of the upper valve body; the upper end of the lower needle valve passes through the center hole of the stepped needle valve seat and is in clearance fit with the large end hole at the upper part of the stepped center hole of the needle valve seat. The ratio of the lower end diameter D1 of the lower needle valve to the small end hole diameter D2 at the lower part of the stepped center hole of the needle valve seat is: D1 / D2 = 0.77~0.

83.

2. The marine dual-fuel engine methanol injector as described in claim 1, characterized in that, The upper ratchet is made of an iron-nickel alloy.

3. The marine dual-fuel engine methanol injector as described in claim 1, characterized in that, The helix angle α of the spiral groove is ≥65°.

4. The marine dual-fuel engine methanol injector as described in claim 1, characterized in that, Both the outer circumferential surface of the upper valve stem and the outer circumferential surface of the lower needle valve are chrome-plated, and the surface hardness of the outer circumferential surface of the upper valve stem and the outer circumferential surface of the lower needle valve are both HRC≥50.

Images