A proportional valve for a high-pressure pump of a coal-fired engine

Abstract

The present invention discloses a proportional valve for a high-pressure pump of a coal-fired engine, comprising a sliding valve pair, a sliding valve spring, a sliding valve spring seat, an adjusting screw, a relief valve assembly, a throttle screw, a proportional electromagnet, and a valve body. The sliding valve pair is provided with a sealing ring and a lubricating oil channel, the sliding valve is provided with a center hole, and the working surface is plated with a special coating. The sliding valve spring seat is provided with a center hole and a concave spherical surface. The adjusting screw is provided with a center hole and a spherical surface. The relief valve assembly is provided with a sealing ring, the working surface of the relief valve is plated with a special coating, the relief valve spring seat is provided with a center hole, and the adjusting screw is provided with a center hole. The valve body is provided with a fuel inlet interface, a fuel return interface, a lubricating oil interface, and a lubricating oil channel, which lubricates the proportional valve while also providing lubricating oil for the high-pressure pump. The present invention can adapt to ultra-clean coal-fired liquid fuel and can effectively improve the sensitivity, stability, reliability, and service life of the proportional valve.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and in particular to a proportional valve for a high-pressure pump of a coal-fired engine. Background Art

[0002] Coal is the primary source of mineral energy in my country. Efficient and clean utilization of domestic coal resources can meet increasingly stringent energy, power, and environmental demands. The development and maturity of ultra-clean coal liquid fuel technology has provided a new approach for the efficient and clean utilization of coal. Ultra-clean coal liquid fuel offers low cost, high thermal efficiency, lower post-combustion emissions than fuel oil, is non-flammable and non-explosive, and is easy to store and transport. Like fuel oil, ultra-clean coal liquid fuel is also a suitable fuel for engines. Coal-fired engines fueled by ultra-clean coal liquid fuel are primarily used in industries such as power generation and transportation.

[0003] The fuel injection system is the heart of a coal-fired engine and has a significant impact on engine performance. The high-pressure pump is one of the most critical components of a coal-fired engine's fuel injection system, and its performance directly impacts the system's operation. A proportional valve, typically installed at the pump's fuel inlet, controls the amount of fuel entering the pump based on demand, balancing the pump's supply with the system's injection requirements and regulating fuel injection pressure.

[0004] As a key control component, the proportional valve requires high sensitivity, stability, reliability, and longevity. However, compared to fuel oil, ultra-clean coal fuel liquid has larger particles and is more corrosive, which can adversely affect the proportional valve. Existing proportional valves in engine high-pressure pumps are difficult to adapt to ultra-clean coal fuel liquid, and their structure, performance, and service life require further optimization and improvement. Therefore, further research and development of proportional valve technology is needed to adapt it not only to fuel oil but also to ultra-clean coal fuel liquid to meet the development needs of coal-fired engines. Summary of the Invention

[0005] In order to adapt to ultra-clean coal-fired liquid fuel, overcome the defects in the existing technology, and meet the development needs of coal-fired engines, the present invention provides a proportional valve for a high-pressure pump of a coal-fired engine to adapt to both diesel and ultra-clean coal-fired liquid fuel, reduce corrosion and wear of moving parts, reduce slide valve sticking, fuel leakage and other faults, increase reliability, and extend service life.

[0006] The technical solutions of the present invention are as follows:

[0007] The invention provides a proportional valve for a high-pressure pump of a coal-fired engine, comprising a proportional electromagnet and a valve body, a slide valve assembly installed in a first valve cavity of the valve body, a relief valve assembly in a second valve cavity, and an adjusting screw installed in the first cavity.

[0008] According to one embodiment of the present invention, the first valve chamber A and the first cavity B are connected and are located on the same central axis. The first valve chamber A and the second valve chamber C are arranged side by side and are connected through an oil hole. A first annular groove A1 and a second annular groove A2 are provided in the first valve chamber A, and a third annular groove C1 is provided in the second valve chamber C.

[0009] According to one embodiment of the present invention, the sliding valve assembly includes a sliding valve pair, a sliding valve spring and a sliding valve spring seat; the sliding valve pair includes a sliding valve and a sliding valve sleeve with a clearance fit; one end of the adjusting screw extends into the valve body and is connected to the sliding valve spring seat, one end of the sliding valve spring is installed on the sliding valve spring seat, and the other end is against one end of the sliding valve, and the other end of the sliding valve is connected to the push rod of the proportional electromagnet; the push rod of the proportional electromagnet drives the sliding valve to move, thereby adjusting the amount of fuel entering the high-pressure pump; the adjusting screw adjusts the opening pressure of the sliding valve; the sliding valve is respectively provided with sealing rings near both ends, and the sliding valve sleeve is respectively provided with sealing rings near both ends and in the middle to prevent the super-clean coal fuel liquid from leaking from the gap between the sliding valve pair and from the gap between the sliding valve sleeve and the valve body.

[0010] According to one embodiment of the present invention, the relief valve assembly includes a relief valve and a relief valve sleeve with a clearance fit; the relief valve sleeve is provided with sealing rings on both sides of the relief valve port, which are respectively matched with the valve body and the relief valve, to prevent the ultra-clean coal fuel liquid from leaking from the gap between the relief valve and the relief valve sleeve and the gap between the relief valve sleeve and the valve body.

[0011] According to one embodiment of the present invention, the spool valve, the spool valve spring seat, and the adjusting screw are all provided with central holes and are sequentially connected. The spool valve is provided with multiple radial through holes at one end, distal from the guide cone, and near the end surface, which are connected to the central hole of the spool valve. This allows the interior cavity of the proportional valve body to communicate with the external space, preventing the confined air in the proportional valve body cavity from affecting the movement of the spool valve. The guide cone serves as a guide during assembly.

[0012] According to one embodiment of the present invention, the sliding valve sleeve is provided with a central hole for accommodating the sliding valve, and the sliding valve sleeve is provided with a plurality of flow control windows and a plurality of through holes evenly distributed along the circumference in the middle section. The flow control windows are connected to the overflow valve assembly through the annular groove A1 and the oil channel, and the through holes are connected to the annular groove A2 and the oil hole to connect to the high-pressure pump.

[0013] According to an embodiment of the present invention, the slide valve is provided with an annular groove in the middle section. By controlling the movement of the slide valve, the flow area of ​​the flow control window is changed to adjust the amount of fuel entering the high-pressure pump.

[0014] According to an embodiment of the present invention, the sliding valve is respectively designed with a first sealing ring groove and a second sealing ring groove on both sides of the ring groove for installing a sealing ring.

[0015] According to an embodiment of the present invention, a special coating is applied to the working surface of the slide valve to improve the corrosion resistance, wear resistance and anti-seizure capability of the slide valve.

[0016] According to one embodiment of the present invention, the sliding valve sleeve has first and second lubricating oil ring grooves on the outer surfaces of both ends of the midsection, respectively, and third and fourth lubricating oil ring grooves on corresponding positions on the inner bore surface, respectively. The first and third lubricating oil ring grooves are connected by a plurality of oil holes evenly distributed along the circumference, and the second and fourth lubricating oil ring grooves are connected by a plurality of oil holes evenly distributed along the circumference. Lubricating oil can flow from the first and second lubricating oil ring grooves into the third and fourth lubricating oil ring grooves, and then into the clearance between the sliding valve components for lubrication.

[0017] According to an embodiment of the present invention, an annular boss is designed at one end of the sliding valve sleeve for mounting a sealing ring.

[0018] According to an embodiment of the present invention, a third sealing ring groove and a fourth sealing ring groove are designed at one end and the middle position of the sliding valve sleeve for installing a sealing ring.

[0019] According to one embodiment of the present invention, the slide valve spring seat is provided with a concave spherical surface, and the adjusting screw is designed with a spherical surface matching therewith, so that the slide valve spring can be automatically aligned during the movement of the slide valve or the turning of the adjusting screw.

[0020] According to one embodiment of the present invention, the relief valve assembly further includes a relief valve spring, a relief valve spring seat, a plug, a nut and an adjusting screw; the relief valve sleeve is installed in the valve body through a threaded connection, the end of the adjusting screw presses against the relief valve spring seat, one end of the relief valve spring is installed on the relief valve spring seat, the other end of the relief valve spring presses against one end of the relief valve, and the adjusting screw adjusts the opening pressure of the relief valve.

[0021] According to one embodiment of the present invention, a special coating is plated on the working surface of the relief valve to improve the corrosion resistance, wear resistance and anti-seizure capability of the relief valve.

[0022] According to one embodiment of the present invention, a sealing cone surface is provided on the relief valve sleeve, and a sealing cone surface is provided on the relief valve that cooperates with the sealing cone surface. The closing and opening of the relief valve assembly are controlled by the movement of the relief valve, and the connection and disconnection with the flow control window on the sliding valve sleeve are achieved through the oil hole.

[0023] According to one embodiment of the present invention, a fifth sealing ring groove and a sixth sealing ring groove are provided on both sides of the overflow port, respectively, on the outer periphery and the center hole surface of the overflow valve sleeve, for installing sealing rings to prevent the ultra-clean coal fuel liquid from leaking from the gap between the overflow valve and the overflow valve sleeve and the gap between the overflow valve sleeve and the valve body.

[0024] According to one embodiment of the present invention, the overflow valve, the overflow valve spring seat and the adjusting screw are all designed with a central hole, which are connected in sequence to connect the inner cavity of the overflow valve assembly with the external space, thereby preventing the enclosed air in the inner cavity from affecting the movement of the overflow valve.

[0025] According to one embodiment of the present invention, the valve body is provided with a fuel inlet interface, a fuel return interface and a lubricating oil interface; the fuel inlet interface is connected to the first annular groove A1 through an oil hole; the fuel return interface

[0026] (82) is connected to the third ring groove C1 through the oil hole; the lubricating oil interface is connected to the first lubricating oil ring groove (126) through the oil hole; the lubricating oil interface is connected to the second lubricating oil ring groove through the oil hole.

[0027] According to one embodiment of the present invention, the valve body is provided with a lubricating oil channel, the throttling screw is installed in the lubricating oil channel, the lubricating oil interface is connected to the high-pressure pump through the lubricating oil channel, and the valve body is designed with an oil hole connecting the second annular groove A2 and the high-pressure pump.

[0028] The present invention provides a proportional valve for a high-pressure pump of a coal-fired engine, which is adaptable to ultra-clean coal liquid fuel and can effectively improve the sensitivity, stability, reliability and service life of the proportional valve. Specific beneficial effects include at least:

[0029] 1. At least two sealing rings are designed on the slide valve to prevent the mixture of ultra-clean coal fuel liquid and lubricating oil from leaking from the gap between the slide valve parts. A sealing ring is designed at each end of the slide valve sleeve to prevent the mixture of ultra-clean coal fuel liquid and lubricating oil from leaking from the gap between the slide valve sleeve and the proportional valve body, thereby avoiding corrosion of parts such as the slide valve spring and the proportional valve solenoid.

[0030] 2. A center hole is designed in the slide valve. A plurality of radial through holes evenly distributed along the circumferential direction are designed on the end of the slide valve away from the conical surface to communicate with the center hole of the slide valve. The slide valve spring seat is also designed with a center hole, and the adjusting screw is also designed with a center hole, so that the inner cavity of the proportional valve body is connected with the external space to prevent the enclosed air in the cavity of the proportional valve body from affecting the movement of the slide valve.

[0031] 3. The working surface of the slide valve and the relief valve is coated to improve the corrosion resistance, wear resistance and anti-seizure ability of the slide valve and the relief valve, and can adapt to the characteristics of ultra-clean coal fuel liquid with large particles and high corrosiveness.

[0032] 4. Lubricating oil channels are designed in the slide valve sleeve and the proportional valve body to provide lubricating oil for the slide valve pair, improve the anti-seizure ability of the slide valve pair, and also provide lubricating oil for the high-pressure pump.

[0033] 5. The slide valve spring seat is designed with a concave spherical surface, and the adjusting screw is designed with a matching spherical surface. During the movement of the slide valve or the turning of the adjusting screw, the slide valve spring can automatically align.

[0034] 6. Both the slide valve and the relief valve adopt the screw pressure adjustment method. Compared with the gasket pressure adjustment method, the screw pressure adjustment method is more convenient.

[0035] 7. A sealing ring is designed on the outer circle of the relief valve sleeve near one end of the hexagonal structure to prevent the ultra-clean coal fuel liquid from leaking into the external space. A sealing ring is designed inside the relief valve hole to prevent the ultra-clean coal fuel liquid from leaking through the gap between the relief valve and the relief valve sleeve, and to avoid corrosion of parts such as the spring.

[0036] 8. The relief valve spring seat is designed with a center hole, and the adjusting screw is designed with a center hole to make the inner cavity of the relief valve assembly and the outside

[0037] The spaces are connected to prevent the enclosed air in the inner cavity from affecting the movement of the relief valve.

[0038] 9. A throttling screw is installed in the lubricating oil hole leading to the high-pressure pump, which can limit the amount of lubricating oil entering the high-pressure pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention is further described below with reference to the accompanying drawings and embodiments:

[0040] Figure 1 This is the outline diagram of the proportional valve of the high-pressure pump of a coal-fired engine;

[0041] Figure 2 Cross-section of the proportional valve of the high-pressure pump of a coal-fired engine Figure 1 ;

[0042] Figure 3 Cross-section of the proportional valve of the high-pressure pump of a coal-fired engine Figure 2 ;

[0043] Figure 4 It is a cross-sectional view of the sliding valve assembly;

[0044] Figure 5 A cross-sectional view of the slide valve;

[0045] Figure 6 It is a cross-sectional view of the sliding valve sleeve;

[0046] Figure 7 A cross-sectional view of the relief valve assembly;

[0047] Figure 8It is a cross-sectional view of the relief valve;

[0048] Figure 9 It is a cross-sectional view of the relief valve sleeve;

[0049] Figure 10 The valve body is cut away Figure 1 ;

[0050] Figure 11 The valve body is cut away Figure 2 ;

[0051] Figure 12 The valve body is cut away Figure 3 ;

[0052] Figure 13 Schematic diagram of the lubricating oil hole of the proportional valve Figure 1 ;

[0053] Figure 14 Schematic diagram of the lubricating oil hole of the proportional valve Figure 2 .

[0054] Explanation of main reference numerals: 1-sliding valve pair, 11-sliding valve, 111-sliding valve center hole, 112-sliding valve radial through hole, 113-sliding valve ring groove, 114-first sealing ring groove, 115-second sealing ring groove, 12-sliding valve sleeve, 121-annular boss, 122-sliding valve sleeve center hole, 123-third sealing ring groove, 124-fourth sealing ring groove, 125-flow control window, 126-first lubricating oil ring groove, 127-second lubricating oil ring groove, 128-third lubricating oil ring groove, 129-fourth lubricating oil ring groove, 130-sliding valve sleeve through hole, 2-sliding valve spring, 3-sliding valve spring seat, 4-adjusting screw, 5-relief valve assembly, 51-relief Valve, 511-sealing cone, 52-overflow valve sleeve, 521-fifth sealing ring groove, 522-sixth sealing ring groove, 523-overflow port, 524-sealing cone, 53-overflow valve spring, 54-overflow valve spring seat, 55-screw plug, 56-nut, 57-adjusting screw, 6-throttle screw plug, 7-proportional solenoid, 8-valve body, 81-fuel inlet interface, 82-return fuel interface, 83-lubricating oil interface, 84-first oil hole, 85-second oil hole, 86-lubricating oil channel, 87-oil hole, 88-oil hole, A-first valve cavity, A1-first annular groove, A2-second annular groove, B-second valve cavity, C-first cavity, C1-third annular groove. DETAILED DESCRIPTION

[0055] The structure of the present invention is further described in detail below with reference to the accompanying drawings.

[0056] like Figure 1 、 2As shown in Figures 3 and 10, a proportional valve for a high-pressure pump of a coal-fired engine in this embodiment includes a sliding valve pair 1, a sliding valve spring 2, a sliding valve spring seat 3, an adjusting screw 4, a relief valve assembly 5, a throttle screw 6, a proportional solenoid 7 and a valve body 8.

[0057] The valve body 8 comprises a first valve chamber A, a first cavity B, and a second valve chamber C. The first valve chamber A and the first cavity B are connected and located on the same central axis. The first cavity A and the second valve chamber C are arranged side by side and connected through an oil hole. A first annular groove A1 and a second annular groove A2 are provided in the first valve chamber A, and a third annular groove C1 is provided in the second valve chamber C.

[0058] The spool valve assembly 1, spool valve spring 2, and spool valve spring seat 3 are installed in the first valve chamber A of the valve body 8. The spool valve assembly 1 includes a spool valve 11 and a spool valve sleeve 12. The concave spherical surface 32 of the spool valve spring seat 3 contacts and engages with the spherical surface 42. The spool valve spring 2 is installed between the spool valve 11 and the spool valve spring seat 3. The spool valve sleeve is connected to the housing of the proportional solenoid, which presses the spool valve sleeve against the valve body.

[0059] The proportional electromagnet 7 is tightly fitted with the valve body and connected to the valve body 8 via screws, thereby pressing the sliding valve assembly 1 into the first cavity A.

[0060] The adjusting screw 4 is installed in the first cavity B of the valve body 8 and can be locked by a nut.

[0061] The relief valve assembly 5 is installed in the second valve chamber C through a threaded connection, and includes a relief valve 51, a relief valve sleeve 52, a relief valve spring 53, a relief valve spring seat 54, a screw plug 55, a nut 56 and an adjusting screw 57.

[0062] Ultra-clean coal fuel liquid flows from the fuel inlet port 81 of the valve body 8 through the oil hole into the first annular groove A1. It then enters the slide valve annular groove 113 through the flow control window 125, and then enters the high-pressure pump through the slide valve sleeve through-hole 130 and the oil hole 87. Furthermore, the ultra-clean coal fuel liquid flows from the first annular groove A1 through the oil hole to the relief valve assembly 5. When the pressure of the ultra-clean coal fuel liquid exceeds the opening pressure of the relief valve assembly 5, the relief valve assembly 5 opens, and the ultra-clean coal fuel liquid enters the third annular groove C1. It then flows through the oil hole to the return fuel port 82 and back to the fuel tank. The proportional solenoid 7 drives the movement of the slide valve 11, adjusting the amount of fuel entering the high-pressure pump by changing the flow area of ​​the flow control window 125.

[0063] In one embodiment of the present invention, Figure 5As shown, the slide valve 11 is designed with a central hole 111. Near the end of the slide valve 11, distal from the conical surface, x radial through holes 112 are designed. An annular groove 113 is designed around the outer periphery of the midsection of the slide valve 11, connecting the flow control window 125 with the through hole 130. A first sealing ring groove 114 and a second sealing ring groove 115 are designed on either side of the annular groove 113. The working surface of the slide valve 11 is coated with a special coating, such as tungsten carbide in this embodiment.

[0064] In one embodiment of the present invention, Figure 6 As shown, one end of the sliding valve sleeve 12 is designed with an annular boss 121 for mounting a sealing ring. The sliding valve sleeve 12 is designed with a central hole 122 for accommodating the sliding valve 11. A third sealing ring groove 123 is designed in the middle section of the sliding valve sleeve 12, and a fourth sealing ring groove 124 is designed at the other end. The middle section of the sliding valve sleeve 12 is designed with a circle of flow control windows 125 evenly distributed along the circumference. A circle of through holes 130 is also designed with a certain distance between them, and the distance between the two should be less than the width of the annular groove 113.

[0065] On the outer surface of the sliding valve sleeve 12, on the outer sides of the flow control window 125 and the outer sides of the through hole 130 at both ends of the middle section, a first lubricating oil ring groove 126 and a second lubricating oil ring groove 127 are respectively designed, and the inner hole surface of the sliding valve sleeve 12 is correspondingly designed with a third lubricating oil ring groove 128 and a fourth lubricating oil ring groove 129. The first lubricating oil ring groove 126 and the third lubricating oil ring groove 128 are connected by a plurality of oil holes evenly distributed along the circumference, and the second lubricating oil ring groove 127 and the fourth lubricating oil ring groove 129 are connected by a plurality of oil holes evenly distributed along the circumference.

[0066] In this embodiment, Figure 2 As shown, the slide valve spring seat 3 is designed with a central hole. The slide valve spring seat 3 is designed with a concave spherical surface. The adjusting screw 4 is designed with a central hole. The adjusting screw 4 is designed with a spherical surface that matches the concave spherical surface.

[0067] In this embodiment, Figure 7 、 8 As shown in Figures 9 and 9, the relief valve housing 52 of the relief valve assembly 5 is provided with a circle of relief ports 523 connected to the central hole. On either side of the relief port 523, a fifth sealing ring groove 521 and a sixth sealing ring groove 522 are provided on the outer periphery and the central hole of the relief valve housing 52, respectively. Sealing rings are installed therein to prevent leakage of ultra-clean coal fuel liquid from the gap between the relief valve and the relief valve housing, and from the gap between the relief valve housing and the valve body of the proportional valve.

[0068] The relief valve spring seat 54 is designed with a central hole, and the adjusting screw 57 is designed with a central hole, so that the inner cavity of the relief valve assembly is connected with the external space to prevent the enclosed air in the inner cavity from affecting the movement of the relief valve.

[0069] The working surface of the relief valve 51 is plated with a special coating, for example, tungsten carbide in this embodiment.

[0070] In one embodiment of the present invention, Figure 2 As shown, the throttle screw plug 6 is designed with a throttle hole. The throttle screw plug 6 is designed with an inner hexagonal structure.

[0071] In one embodiment of the present invention, Figure 10 、 11 As shown in Figures 1 and 12, the valve body 8 is designed with a first valve chamber A that accommodates the proportional solenoid 7, the sliding valve assembly 1, the sliding valve spring 2, and the sliding valve spring seat 3; a first cavity B that accommodates the adjusting screw 4; and a second valve chamber C that accommodates the relief valve assembly 5. A first annular groove A1 and a second annular groove A2 are designed within the first valve chamber A. An annular groove C1 is designed within the second valve chamber C. The first valve chamber A and the first cavity B are connected, and the two cavities are located on the same central axis. The second valve chamber C is arranged side by side with the first cavity B and is connected to the first valve chamber A through an oil hole.

[0072] The valve body 8 is designed with a fuel inlet interface 81, a fuel return interface 82 and a lubricating oil interface 83. The fuel inlet interface 81 is connected to the first annular groove A1 through an oil hole. The fuel return interface 82 is connected to the third annular groove C1 through an oil hole. The lubricating oil interface 83 is connected to the first lubricating oil annular groove 126 through an oil hole 84. The lubricating oil interface 83 is connected to the second lubricating oil annular groove 127 through an oil hole 85. The valve body 8 is designed with a lubricating oil channel 86. The throttle screw 6 is installed in the lubricating oil channel 86. The lubricating oil interface 83 is connected to the high-pressure pump through the lubricating oil channel 86. The valve body 8 is designed with an oil hole connecting the second annular groove A2 and the high-pressure pump

[0073] 87. The valve body 8 is designed with 4 screw holes to facilitate integration of the proportional valve into the high-pressure pump.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A proportional valve for a high-pressure pump of a coal-fired engine, comprising a proportional solenoid (7) and a valve body (8), a slide valve assembly installed in a first valve cavity (A) of the valve body (8), a relief valve assembly (5) in a second valve cavity (C), and an adjusting screw (4) installed in a first cavity (B); characterized in that: The first valve chamber (A) and the first cavity (B) are connected and located on the same central axis. The first valve chamber (A) and the second valve chamber (C) are arranged in parallel and connected through an oil hole (88). A first annular groove (A1) and a second annular groove (A2) are provided in the first valve chamber (A), and a third annular groove (C1) is provided in the second valve chamber (C). The slide valve assembly includes a slide valve pair (1), a slide valve spring (2) and a slide valve spring seat (3); the slide valve pair (1) includes a slide valve (11) and a slide valve sleeve (12) with clearance fit; one end of the adjusting screw (4) extends into the valve body and is connected to the slide valve spring seat (3); one end of the slide valve spring (2) is installed on the slide valve spring seat (3), and the other end abuts against one end of the slide valve (11); the other end of the slide valve (11) is connected to the push rod of the proportional solenoid (7) The push rod of the proportional electromagnet (7) drives the slide valve (11) to move and adjust the amount of fuel entering the high-pressure pump; the regulating screw (4) adjusts the opening pressure of the slide valve (11); the slide valve (11) is provided with sealing rings at positions near both ends, and the slide valve sleeve (12) is provided with sealing rings at positions near both ends and in the middle to prevent the ultra-clean coal fuel liquid from leaking from the gap between the slide valve pair (1) and from the gap between the slide valve sleeve (12) and the valve body (8); The relief valve assembly (5) comprises a relief valve (51) and a relief valve sleeve (52) with clearance fit; the relief valve sleeve (52) is provided with sealing rings on both sides of the overflow port (523) that fit with the valve body (8) and the relief valve (51), respectively, to prevent the ultra-clean coal fuel liquid from leaking from the gap between the relief valve (51) and the relief valve sleeve (52) and the gap between the relief valve sleeve (52) and the valve body (8); The slide valve (11), the slide valve spring seat (3) and the adjusting screw (4) are all provided with a central hole and are connected in sequence; the slide valve (11) is provided with a plurality of radial through holes (112) at an end away from the guide cone surface, near the end surface, which are connected to the central hole of the slide valve, so that the inner cavity of the proportional valve body is connected with the external space, thereby preventing the enclosed air in the inner cavity of the proportional valve body from affecting the movement of the slide valve; The sliding valve sleeve (12) is provided with a central hole (122) for accommodating the sliding valve (11), and the sliding valve sleeve (12) is provided with a plurality of flow control windows (125) uniformly distributed along the circumference and a plurality of through holes (130) uniformly distributed along the circumference in the middle section, the flow control windows (125) are connected to the overflow valve assembly (5) through the first annular groove (A1) and the oil passage, and the through holes (130) are connected to the second annular groove (A2) and the oil hole (87), and further connected to the high-pressure pump; The slide valve (11) is provided with an annular groove (113) in the middle section thereof. By moving the slide valve (11), the flow area of ​​the flow control window (125) is changed to adjust the amount of fuel entering the high-pressure pump. The slide valve (11) is provided with a first sealing ring groove (114) and a second sealing ring groove (115) on both sides of the ring groove (113), respectively, for installing a sealing ring; The outer surfaces of the sliding valve sleeve (12) at both ends of the middle section are respectively provided with a first lubricating oil ring groove (126) and a second lubricating oil ring groove (127), and the inner hole surface is respectively provided with a third lubricating oil ring groove (128) and a fourth lubricating oil ring groove (129) at corresponding positions. The first lubricating oil ring groove (126) and the third lubricating oil ring groove (128) are connected through a plurality of oil holes evenly distributed along the circumference, and the second lubricating oil ring groove (127) and the fourth lubricating oil ring groove (129) are connected through a plurality of oil holes evenly distributed along the circumference. Lubricating oil can enter the third lubricating oil ring groove (128) and the fourth lubricating oil ring groove (129) from the first lubricating oil ring groove (126) and the second lubricating oil ring groove (127), and then enter the gap of the sliding valve pair (1) for lubrication. One end of the sliding valve sleeve (12) is designed with an annular boss (121) for mounting a sealing ring; A third sealing ring groove (123) and a fourth sealing ring groove (124) are designed at one end and the middle position of the sliding valve sleeve (12) for installing a sealing ring; The valve body (8) is provided with a fuel inlet interface (81), a fuel return interface (82), and a lubricating oil interface (83); the fuel inlet interface (81) is connected to the first annular groove (A1) through an oil hole; the fuel return interface (82) is connected to the third annular groove (C1) through an oil hole; the lubricating oil interface (83) is connected to the first lubricating oil annular groove (126) through an oil hole (84); the lubricating oil interface (83) is connected to the second lubricating oil annular groove (127) through another oil hole (85); The valve body (8) is provided with a lubricating oil passage (86), a throttling screw (6) is installed in the lubricating oil passage (86), the lubricating oil interface (83) is connected to the high-pressure pump through the lubricating oil passage (86), and the valve body (8) is designed with an oil hole (87) that connects the second annular groove (A2) and the high-pressure pump.

2. The proportional valve for a high-pressure pump of a coal-fired engine according to claim 1, characterized in that: The slide valve spring seat (3) is provided with a concave spherical surface, and the adjusting screw (4) is designed with a spherical surface that matches the concave spherical surface, so that the slide valve spring can be automatically aligned during the movement of the slide valve or the turning of the adjusting screw.

3. The proportional valve for a high-pressure pump of a coal-fired engine according to claim 1, characterized in that: The relief valve assembly (5) further comprises a relief valve spring (53), a relief valve spring seat (54), a screw plug (55), a nut (56) and an adjusting screw (57); the relief valve sleeve (52) is mounted in the valve body (8) by a threaded connection, the end of the adjusting screw (57) bears against the relief valve spring seat (54), one end of the relief valve spring (53) is mounted on the relief valve spring seat (54), the other end of the relief valve spring (53) bears against one end of the relief valve (51), and the adjusting screw (57) adjusts the opening pressure of the relief valve (51); The relief valve sleeve (52) is provided with a sealing conical surface (524), and the relief valve (51) is provided with a sealing conical surface (511) that cooperates with the sealing conical surface (524). The movement of the relief valve (51) controls the closing and opening of the relief valve assembly (5), and the connection and disconnection with the flow control window (125) on the sliding valve sleeve (12) are achieved through the oil hole.

4. The proportional valve for a high-pressure pump of a coal-fired engine according to claim 1, characterized in that: On both sides of the overflow port (523), a fifth sealing ring groove (521) and a sixth sealing ring groove (522) are provided on the outer periphery and the central hole surface of the overflow valve sleeve (52), respectively, for installing sealing rings to prevent the ultra-clean coal fuel liquid from leaking from the gap between the overflow valve (51) and the overflow valve sleeve (52) and the gap between the overflow valve sleeve (52) and the valve body (8).

5. The proportional valve for a high-pressure pump of a coal-fired engine according to claim 3, characterized in that: The relief valve (51), the relief valve spring seat (54) and the adjusting screw (57) are all designed with a central hole, which are connected in sequence so that the inner cavity of the relief valve assembly is connected with the external space, thereby preventing the enclosed air in the inner cavity from affecting the movement of the relief valve.

6. The proportional valve for a high-pressure pump of a coal-fired engine according to any one of claims 1 to 5, characterized in that: The working surfaces of the slide valve (11) and the relief valve (51) are plated with an anti-corrosion and wear-resistant coating, thereby improving the corrosion resistance, wear resistance and anti-seizure capability of the slide valve (11) and the relief valve (51).

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