A common rail fuel injector filtering restrictor valve

Abstract

The present application relates to a kind of common rail fuel injector filtering flow limiting valve, belong to diesel engine technical field.The filtering flow limiting valve of the present application includes: oil inlet connector, valve core, filter element, valve seat and spring.The present application combines laser drilling filter screen with flow limiting valve, provides a flow limiting valve with filtering function, its structure is compact, can be hidden to the inside of the oil inlet connector of common rail fuel injector.The present application not only can complete flow limiting and filtering function of flow limiting valve and laser drilling filter screen, but also can cut off oil line in time when filter screen is blocked, prevent filter screen before and after pressure difference too large when filter screen is blocked, make filter screen produce deformation or damage.The function of the present application is that traditional flow limiting valve and filter screen cannot be realized.

Description

Technical Field

[0001] This invention belongs to the field of diesel engine technology, specifically relating to a common rail injector filter flow restrictor valve. Background Technology

[0002] As the core of next-generation diesel engine technology, the common rail system has been widely used in vehicles, power, ships, and military fields. Common rail systems are continuously evolving towards higher fuel injection pressures, faster injection rates, and more compact structures. This places higher demands on the reliability of the common rail system.

[0003] The filter is an essential part of the common rail system. Its function is to filter out impurities in the fuel and prevent particulate matter from entering the equipment and causing wear. After fine filtration, the fuel can meet the cleanliness requirements of the common rail system. However, in order to prevent debris generated by wear or failure of the fuel supply pump from entering the injectors and causing them to stick, it is usually necessary to install a slit filter element or a laser-perforated filter screen at the injector inlet.

[0004] Another protective device in the common rail system is the flow restrictor valve, which is a safety protection valve. Its function is to automatically cut off the fuel line when the fuel flow rate is too high, so as to prevent damage to other equipment in the system. It is usually installed at the inlet of the common rail injector or common rail pipe. When the injector is stuck and cannot close, the fuel flow at the injector and common rail pipe inlet will increase abnormally. At this time, the flow restrictor valve closes, so that the fuel line is quickly cut off, preventing excessive fuel from entering the cylinder and damaging the engine. The engine can still run with the fault at this time.

[0005] In existing co-rail systems, a filter and a flow restrictor valve may be installed simultaneously, but they are usually installed separately. When the filter is clogged, it has no force on the valve core of the flow restrictor valve, causing the flow restrictor valve to fail to cut off the oil circuit. Impurities pass through the filter under the pressure difference and enter the injector. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] The technical problem to be solved by the present invention is how to provide a common rail injector filter flow restrictor valve to solve the problem that in the prior art, the common rail system may have a filter device and a flow restrictor valve installed at the same time, but they are generally installed separately. When the filter device is blocked, the filter device has no force on the valve core of the flow restrictor valve, so the flow restrictor valve cannot cut off the oil circuit. Impurities pass through the filter device and enter the injector under the action of pressure difference.

[0008] (II) Technical Solution

[0009] To solve the above-mentioned technical problems, the present invention proposes a common rail injector filter flow restrictor valve, the filter flow restrictor valve comprising: an oil inlet connector, a valve core, a filter element, a valve seat, and a spring;

[0010] The outer thread 1 at the top of the oil inlet connector and the sealing cone surface 1 on the top surface are connected to the external oil pipe; after the thread 2 at the bottom of the oil inlet connector is tightened with the thread 3 inside the valve seat, the sealing plane 1 at the bottom of the oil inlet connector is pressed with the sealing plane 2 inside the valve seat to form a seal; a blind hole is formed inside the oil inlet connector, and the top surface of the blind hole is composed of a limiting surface and a sealing cone surface 2 extending upward around the limiting surface; the sealing cone surface 1 is connected to the blind hole through the oil inlet passage.

[0011] The valve core consists of a coarse cylinder, a thin cylinder, and a trapezoidal column from top to bottom. The outer wall of the coarse cylinder forms the valve core guide surface. A countersunk hole is provided at the top of the coarse cylinder. The sealing cone surface four of the countersunk hole is used to mate with the sealing cone surface two of the oil inlet connector. The outer diameter of the coarse cylinder matches the diameter of the blind hole of the oil inlet connector. Several flow holes are provided in the middle of the thin cylinder. The holes inside the coarse cylinder and the thin cylinder are connected and have the same inner diameter. The side wall of the trapezoidal column forms the sealing cone surface three. During assembly, a spring is fitted around the thin cylinder.

[0012] The filter element consists of, from top to bottom: a ring with a top limiting cone surface and a filter screen. The outer diameter of the ring is interference-fitted with the inner diameter of the valve core, and the limiting cone surface at the top of the ring is located between sealing cone surface two and sealing cone surface four, for mating with sealing cone surface two and sealing cone surface four.

[0013] The valve seat is a cylindrical tube with an internal through hole including an upper mounting hole and a lower oil outlet hole. The mounting hole is coarser and the oil outlet hole is finer. The top of the mounting hole is threaded with thread three and the bottom is a sealing plane two. The bottom side of the mounting hole is connected to the low-pressure return oil circuit through the return oil passage. At the bottom of the mounting hole, it is connected to the downstream high-pressure oil circuit through the countersunk hole and the oil outlet hole. The side wall of the countersunk hole is a sealing cone surface five, which is used to mate with the sealing cone surface three of the valve core.

[0014] Furthermore, the top of the spring rests against the bottom of the thick cylinder, and the bottom of the spring rests against the sealing plane.

[0015] Furthermore, the length of the valve core is the same as the length of the blind hole.

[0016] Furthermore, the length of the filter element is the same as or slightly shorter than the length of the through hole inside the valve core.

[0017] Furthermore, the filter screen is a laser-perforated filter screen.

[0018] Furthermore, the sealing cone surface two of the oil inlet connector and the sealing cone surface four of the countersunk hole at the top of the valve core form a seal under the pressure of the spring force; the limiting surface, the limiting cone surface and the sealing cone surface four restrict the relative movement between the filter element and the valve core.

[0019] Furthermore, the valve core guide surface transitions to the inner wall of the oil inlet connector with a clearance of 0.01~0.03mm, ensuring that the valve core remains coaxial with the inner wall of the oil inlet connector during operation, and maintaining the pressure on the upper part of the valve core when the sealing cone surface two separates from the sealing cone surface four.

[0020] Furthermore, the valve seat return oil passage is connected to the low-pressure return oil passage, and the key structure of the valve seat can be directly machined on the basis of the injector body.

[0021] Furthermore, when fuel flows normally, the valve core is at the top under the action of spring force. At this time, the sealing cone surface three and the sealing cone surface five are separated. Fuel flows into the inner cavity of the filter element through the oil inlet channel. After the particles are filtered by the laser-perforated filter screen, it flows out through the flow hole of the valve core. Finally, the fuel flows into the high-pressure oil circuit of the injector through the oil outlet hole of the valve seat.

[0022] Furthermore, when the injector becomes stuck, the fuel flow rate increases abnormally, and a large pressure difference is generated between the upper and lower end faces of the valve core, causing the valve core to move downward against the spring force. At this time, the sealing cone surface three and the sealing cone surface five are pressed together to form a seal, cutting off the fuel supply to the downstream high-pressure oil circuit connected to the oil outlet.

[0023] (III) Beneficial Effects

[0024] This invention proposes a common rail injector filter flow restrictor valve. It combines a laser-perforated filter screen with a flow restrictor valve, providing a flow restrictor valve with filtering function. Its compact structure allows it to be concealed inside the fuel inlet connector of the common rail injector. This invention not only performs the flow restrictor valve and laser-perforated filter screen functions, but also promptly cuts off the fuel line when the filter screen becomes clogged, preventing excessive pressure difference across the filter screen that could cause deformation or damage. The functionality of this invention is impossible to achieve with traditional flow restrictor valves and filters. Attached Figure Description

[0025] Figure 1 This invention relates to a common rail injector filter flow limiting valve;

[0026] Figure 2 For oil inlet connector;

[0027] Figure 3 For valve core;

[0028] Figure 4 For filter elements;

[0029] Figure 5 For valve seat;

[0030] Figure 6 It is a spring. Detailed Implementation

[0031] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0032] This invention relates to common rail injectors, and more specifically to a flow limiting valve for a common rail injector.

[0033] The main components and assembly relationships of the common rail injector filter flow restrictor valve of the present invention are as follows: Figure 1-6 As shown.

[0034] The filter flow limiting valve includes: an oil inlet connector, a valve core, a filter element, a valve seat, and a spring;

[0035] The outer thread 1 at the top of the oil inlet connector and the sealing cone surface 1 on the top surface are connected to the external oil pipe; after the thread 2 at the bottom of the oil inlet connector is tightened with the thread 3 inside the valve seat, the sealing plane 1 at the bottom of the oil inlet connector is pressed with the sealing plane 2 inside the valve seat to form a seal.

[0036] A blind hole is formed inside the oil inlet connector. The top surface of the blind hole consists of a limiting surface and a sealing cone surface 2 extending upward around the limiting surface. The sealing cone surface 1 communicates with the blind hole through the oil inlet passage.

[0037] The valve core consists of a coarse cylinder, a thin cylinder, and a trapezoidal column from top to bottom. The outer wall of the coarse cylinder forms the valve core guide surface. A countersunk hole is provided at the top of the coarse cylinder. The sealing cone surface four of the countersunk hole is used to mate with the sealing cone surface two of the oil inlet connector. The outer diameter of the coarse cylinder matches the diameter of the blind hole of the oil inlet connector. Several flow holes are provided in the middle of the thin cylinder. The holes inside the coarse cylinder and the thin cylinder are connected and have the same inner diameter. The side wall of the trapezoidal column forms the sealing cone surface three. During assembly, a spring is fitted around the thin cylinder.

[0038] The filter element comprises, from top to bottom: a ring with a top limiting cone surface and a filter screen. The outer diameter of the ring is interference-fitted with the inner diameter of the valve core, and the limiting cone surface at the top of the ring is located between sealing cone surface two and sealing cone surface four, for mating with sealing cone surface two and sealing cone surface four.

[0039] The valve seat is a cylindrical tube with an internal through hole including an upper mounting hole and a lower oil outlet hole. The mounting hole is coarser and the oil outlet hole is finer. The top of the mounting hole is threaded with thread three and the bottom is a sealing plane two. The bottom side of the mounting hole is connected to the low-pressure return oil circuit through the return oil passage. At the bottom of the mounting hole, it is connected to the downstream high-pressure oil circuit through the countersunk hole and the oil outlet hole. The side wall of the countersunk hole is a sealing cone surface five, which is used to mate with the sealing cone surface three of the valve core.

[0040] Furthermore, the top of the spring rests against the bottom of the thick cylinder, and the bottom of the spring rests against the sealing plane.

[0041] Furthermore, the length of the valve core is approximately the same as the length of the blind hole.

[0042] Furthermore, the length of the filter element is the same as or slightly shorter than the length of the through hole inside the valve core.

[0043] Furthermore, the filter screen is a laser-perforated filter screen.

[0044] The sealing cone surface two of the oil inlet connector and the sealing cone surface four of the countersunk hole at the top of the valve core form a seal under the pressure of the spring force; the limiting surface, the limiting cone surface, and the sealing cone surface four restrict the relative movement between the filter element and the valve core; the valve core guide surface transitions to the inner wall of the oil inlet connector with a clearance of 0.01~0.03mm, ensuring that the valve core remains coaxial with the inner wall of the oil inlet connector during operation, and maintaining the pressure on the upper part of the valve core when the sealing cone surface two separates from the sealing cone surface four; the valve seat return oil passage is connected to the low-pressure return oil passage. Figure 1 The key structure of the valve seat shown can be directly machined from the injector body.

[0045] When fuel flows normally, the valve core is at the top under the action of spring force. At this time, the sealing cone surface three and the sealing cone surface five are separated. The fuel flows into the inner cavity of the filter element through the fuel inlet passage, filters the particles through the laser-perforated filter screen, and then flows out through the flow hole of the valve core. Finally, the fuel flows into the high-pressure fuel circuit of the injector through the fuel outlet hole of the valve seat.

[0046] When the injector jams, the fuel flow rate increases abnormally, and a large pressure difference is generated between the upper and lower end faces of the valve core. This causes the valve core to move downward against the spring force. At this time, the sealing cone surface three and the sealing cone surface five are pressed together to form a seal, cutting off the fuel supply to the downstream high-pressure oil circuit connected to the oil outlet.

[0047] When the filter element becomes clogged over time, its flow capacity decreases, and the pressure difference between the upper and lower ends of the valve core also becomes too large. The pressure difference between the upper and lower ends of the valve core causes the valve core to move downward against the spring force, cutting off the connection between the oil inlet and outlet, thus limiting the flow of the engine.

[0048] This invention combines a laser-perforated filter with a flow restrictor valve, providing a flow restrictor valve with filtering function. Its compact structure allows it to be concealed inside the inlet connector of a common rail injector. It not only performs the flow restriction and filtering functions of both a flow restrictor valve and a laser-perforated filter, but also promptly cuts off the fuel line when the filter becomes clogged, preventing excessive pressure difference across the filter and thus avoiding deformation or damage. This functionality is impossible to achieve with traditional flow restrictor valves and filters.

[0049] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A common rail injector filter flow restrictor valve, characterized in that, The filter flow limiting valve includes: an oil inlet connector, a valve core, a filter element, a valve seat, and a spring; The outer thread 1 at the top of the oil inlet connector and the sealing cone surface 1 on the top surface are connected to the external oil pipe; after the thread 2 at the bottom of the oil inlet connector is tightened with the thread 3 inside the valve seat, the sealing plane 1 at the bottom of the oil inlet connector is pressed with the sealing plane 2 inside the valve seat to form a seal; a blind hole is formed inside the oil inlet connector, and the top surface of the blind hole is composed of a limiting surface and a sealing cone surface 2 extending upward around the limiting surface; the sealing cone surface 1 is connected to the blind hole through the oil inlet passage. The valve core consists of a coarse cylinder, a thin cylinder, and a trapezoidal column from top to bottom. The outer wall of the coarse cylinder forms the valve core guide surface. A countersunk hole is provided at the top of the coarse cylinder. The sealing cone surface four of the countersunk hole is used to mate with the sealing cone surface two of the oil inlet connector. The outer diameter of the coarse cylinder matches the diameter of the blind hole of the oil inlet connector. Several flow holes are provided in the middle of the thin cylinder. The holes inside the coarse cylinder and the thin cylinder are connected and have the same inner diameter. The side wall of the trapezoidal column forms the sealing cone surface three. During assembly, a spring is fitted around the thin cylinder. The top of the spring rests against the bottom of the coarse cylinder, and the bottom of the spring rests against the sealing plane two. The filter element, from top to bottom, includes: a ring with a top limiting cone surface and a filter screen. The outer diameter of the ring is interference-fitted with the inner diameter of the valve core, and the limiting cone surface at the top of the ring is located between sealing cone surface two and sealing cone surface four, for mating with sealing cone surface two and sealing cone surface four. The sealing cone surface two of the oil inlet connector and the sealing cone surface four of the countersunk hole at the top of the valve core form a seal under the pressure of the spring force. The limiting surface, the limiting cone surface, and the sealing cone surface four restrict the relative movement between the filter element and the valve core. The valve seat is a cylindrical tube with an internal through hole including an upper mounting hole and a lower oil outlet hole. The mounting hole is coarser and the oil outlet hole is finer. The top of the mounting hole is threaded with thread three and the bottom is a sealing plane two. The bottom side of the mounting hole is connected to the low-pressure return oil circuit through the return oil passage. At the bottom of the mounting hole, it is connected to the downstream high-pressure oil circuit through the countersunk hole and the oil outlet hole. The side wall of the countersunk hole is a sealing cone surface five, which is used to mate with the sealing cone surface three of the valve core. in, The filter is a laser-perforated filter.

2. The common rail injector filter flow restrictor valve as described in claim 1, characterized in that, The length of the valve core is the same as the length of the blind hole.

3. The common rail injector filter flow restrictor valve as described in claim 2, characterized in that, The length of the filter element is the same as or slightly shorter than the length of the through hole inside the valve core.

4. The common rail injector filter flow restrictor valve as described in claim 1, characterized in that, The valve core guide surface transitions to the inner wall of the oil inlet connector with a clearance of 0.01~0.03mm, ensuring that the valve core remains coaxial with the inner wall of the oil inlet connector during operation. Furthermore, when the second sealing cone surface separates from the fourth sealing cone surface, it helps to maintain the pressure on the upper part of the valve core.

5. The common rail injector filter flow restrictor valve as described in claim 4, characterized in that, The valve seat return oil passage is connected to the low-pressure return oil passage.

6. The common rail injector filter flow restrictor valve as described in any one of claims 1-5, characterized in that, When fuel flows normally, the valve core is at the top under the action of spring force. At this time, the sealing cone surface three and the sealing cone surface five are separated. Fuel flows into the inner cavity of the filter element through the oil inlet passage. After the particles are filtered by the laser-perforated filter screen, it flows out through the flow hole of the valve core. Finally, the fuel flows into the high-pressure oil circuit of the injector through the oil outlet hole of the valve seat.

7. The common rail injector filter flow restrictor valve as described in claim 6, characterized in that, When the injector jams, the fuel flow rate increases abnormally, and a large pressure difference is generated between the upper and lower end faces of the valve core. This causes the valve core to move downward against the spring force. At this time, the sealing cone surface three and the sealing cone surface five are pressed together to form a seal, cutting off the fuel supply to the downstream high-pressure oil circuit connected to the oil outlet.

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