A fuel metering valve for a diesel engine high pressure common rail pump that is resistant to harsh oils

Abstract

A fuel metering valve for a diesel engine high-pressure common rail pump that is resistant to harsh oils includes a valve body and a valve core. A filter is provided at the lower end of the valve body. The valve body and valve core form a flow valve pair. The valve body and valve core are made of corrosion-resistant and oxidation-resistant precipitation-hardened stainless steel. The pair structure and stainless steel material make the present invention easy to process and grind, with high hardness, good wear resistance, high dimensional accuracy, strong resistance to corrosion from harsh oils, and long service life. A filter is provided at the lower end of the valve body to prevent foreign particles from entering the fuel flow cavity, preventing foreign particles from blocking engine moving parts and affecting engine combustion. A buckle is designed at one end of the filter, and the buckle is assembled in the slot of the valve body. Compared with the existing fuel metering valve, the present invention increases the ability to resist foreign particles from harsh oils, is not easy to get stuck, improves engine emission indicators, reduces engine failure rate, improves the ability of parts to resist corrosion from harsh oils, and increases the life of parts.

Description

Technical Field

[0001] The invention relates to the technical field of a fuel metering valve for a diesel engine high pressure common rail pump, in particular to a fuel metering valve for a diesel engine high pressure common rail pump which is resistant to harsh oil products. Background Art

[0002] High-pressure common rail fuel injection system has become one of the main development trends of diesel engine technology in the world today, and is an important means for diesel engines to reduce pollutant emissions. The high-pressure common rail fuel system includes common rail pump, common rail pipe, injector, ECU, sensor and other components. The common rail pump is a key component in the common rail system, and its oil volume is precisely controlled by the metering valve. The metering valve oil volume adjustment is always in the positive pressure zone, and the position close to the plunger cavity makes the oil volume adjustment respond quickly. The metering valve has an important impact on the performance of the common rail pump and is a key component to improve the performance of the common rail pump. In recent years, domestic emission regulations have been continuously upgraded, and the implementation of the National VI emission in July 2019 has put higher and higher requirements on the quality of domestic diesel, and put forward more stringent requirements on the resistance of diesel common rail components to harsh oil products. With the long-term operation of the engine, the wear of parts, mechanical vibration, and material aging are inevitable. The resulting foreign matter and debris will cause the oil quality to deteriorate, which will have a greater impact on engine emissions. As the actuator that controls the fuel entering the engine, the fuel metering valve directly controls the amount of fuel entering the engine. It is crucial to resist and prevent the impurities of harsh oil products for engine performance.

[0003] The existing fuel metering valves used in diesel engine high-pressure common rail pumps are prone to rust, sticking, corrosion and other faults, causing engine performance loss or excessive emissions, and the market feedback shows that the failure rate is relatively high.

[0004] The fuel metering valve is a key component for controlling the fuel entering the engine. Currently, due to the failure of this component in the domestic market, it is impossible to repair the component and can only be replaced directly, resulting in high engine maintenance costs. Summary of the invention

[0005] The above problems can be effectively solved by improving the design and materials.

[0006] A fuel metering valve for a diesel engine high-pressure common rail pump that is resistant to harsh oil products, comprising a rear choke sleeve, a housing, a coil component, a front choke sleeve and a valve body;

[0007] The coil component is provided with a front choke sleeve and a rear choke sleeve, which are connected by welding through a magnetic isolation ring to form a sealed oil storage cavity; the rear choke sleeve and the magnetic isolation ring are connected by laser welding, and the welding point adopts a 45° wedge-shaped surface to improve the welding reliability;

[0008] The front choke sleeve adopts a wedge-shaped magnetic isolation angle, which can adjust the good horizontal characteristics of the electromagnetic force of the metering valve and facilitate proportional control;

[0009] An armature and an armature shaft are provided between the rear choke sleeve and the front choke sleeve, and the armature and the armature shaft are connected by interference fitting;

[0010] A gap sheet is provided on the upper end surface of the front choke sleeve, and the gap sheet can prevent the armature from contacting the front choke sleeve, causing the armature to be unable to demagnetize and return in time; the gap sheet is a circular structure, and three circular protrusions are evenly distributed on both end surfaces, and the circular protrusions provide oil drainage gaps to form a smooth oil drainage gap, thereby avoiding blockage of the oil drainage hole caused by plane contact;

[0011] The lower end of the front choke sleeve is provided with a valve body, and the front choke sleeve and the valve body are connected by radial annular riveting, which avoids the risk of the inner hole of the valve body being deformed due to assembly, resulting in the risk of the valve core being stuck, and also improves the assembly consistency; a valve core is arranged in the valve body to form a flow valve pair, and the valve body and the valve core are made of corrosion-resistant and oxidation-resistant precipitation hardened stainless steel materials. The pair structure and stainless steel materials make the present invention easy to process and grind, with high hardness, good wear resistance, high dimensional accuracy, strong resistance to corrosion from harsh oil products, and long service life; the upper end of the valve core is offset against the plane of the lower end face of the front choke sleeve, which ensures that the initial position of the valve core is accurate and improves the maximum flow consistency;

[0012] A spring is provided at the lower end of the valve core. The spring adopts a conical structure. The conical shape increases the spring ring gap, increases the flow area, and avoids the risk of throttling of the spring ring gap at a large flow rate. A spring seat is installed at the lower end of the spring. An oil inlet hole is provided at the center of the spring seat. The spring seat is assembled in the valve body. The pre-compression stroke of the spring is adjusted by controlling the assembly depth of the spring seat.

[0013] A filter is provided at the lower end of the valve body to prevent foreign particles from entering the fuel flow cavity, thereby preventing foreign particles from blocking the engine moving parts and affecting engine combustion; a buckle is designed at one end of the filter, and the buckle is assembled in the slot of the valve body.

[0014] Furthermore, the coil component is placed inside the shell, and a pressing plate and a corrugated gasket are provided between the coil component and the shell.

[0015] Furthermore, sliding bearings are provided in the rear choke sleeve and the front choke sleeve to provide movement guidance for the armature and the armature shaft, and the armature and the armature shaft can move flexibly in the oil storage cavity.

[0016] Furthermore, the armature shaft initially leaves an empty travel section with the valve core to avoid large dispersion of the armature shaft extension end due to assembly and accumulation of parts size chains, thereby causing poor consistency of maximum flow, and the empty travel section is 0.1 mm.

[0017] Furthermore, a flange is installed on the step end face of the front choke sleeve, and the flange and the front choke sleeve are connected by interference fitting; two steps are provided on the front choke sleeve to prevent the flange from damaging the next-level assembly surface when assembling downward, causing poor welding between the magnetic isolation ring and the front choke sleeve of the next level; the upper end face of the flange is connected to the lower end of the shell.

[0018] Furthermore, a first O-type sealing ring and a second O-type sealing ring are symmetrically provided on the front choke sleeve and the valve body respectively.

[0019] Furthermore, the coil component adopts different interface forms and can be applicable to various connection methods of different host manufacturers.

[0020] The valve body of the present invention is equipped with a precision filter at the oil inlet, which, compared with the existing fuel metering valve, has increased resistance to foreign particles of bad oil products, is not easy to get stuck, improves engine emission indicators, and reduces engine failure rate.

[0021] The flow valve of the present invention adopts corrosion-resistant and oxidation-resistant high-quality precipitation hardened stainless steel material, and compared with the existing fuel metering valve, the ability of the parts to resist corrosion from harsh oil products is improved, and the service life of the parts is increased.

[0022] The present invention greatly increases the operating life of the fuel metering valve under extreme conditions of severe oil products, reduces the frequency of market failures, and reduces maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the present invention.

[0024] Figure 2 1 is a top view of the gap sheet of the present invention.

[0025] Figure 3 It is a side view of the gap piece of the present invention.

[0026] Figure 4 It is a schematic diagram of the structure of the flow valve of the present invention.

[0027] Figure 5 It is a schematic diagram of the structure of the wedge-shaped magnetic isolation corner of the forehead cover of the present invention.

[0028] Figure 6 It is a schematic diagram of the 45° wedge-shaped surface welding structure of the rear choke sleeve and the magnetic isolation ring of the present invention.

[0029] Figure 7 It is a schematic diagram of the structure of the idle travel section between the armature shaft and the valve core of the present invention. DETAILED DESCRIPTION

[0030] like Figure 1As shown, a fuel metering valve for a diesel engine high-pressure common rail pump that is resistant to harsh oil products comprises a rear choke sleeve 1, a housing 5, a coil component 7, a front choke sleeve 9 and a valve body 14:

[0031] The coil component 7 is provided with a front choke sleeve 9 and a rear choke sleeve 1, which are welded and connected by a magnetic isolation ring 6 to form a sealed oil storage cavity; the rear choke sleeve 1 and the magnetic isolation ring 6 are connected by laser welding. Figure 6 As shown, the welding place adopts 45° wedge-shaped surface 21 to connect, which can improve the welding reliability;

[0032] like Figure 5 As shown, the front choke sleeve 9 adopts a wedge-shaped magnetic isolation angle 20, which can adjust the good horizontal characteristics of the electromagnetic force of the metering valve and facilitate proportional control;

[0033] An armature 4 and an armature shaft 10 are provided between the rear choke sleeve 1 and the front choke sleeve 9, and the armature 4 and the armature shaft 10 are connected by interference fitting;

[0034] The upper end surface of the front choke sleeve 9 is provided with a gap sheet 8, which can prevent the armature 4 from contacting the front choke sleeve 9, causing the armature 4 to be unable to demagnetize and recover in time; the gap sheet 8 is a circular structure, such as Figure 2 and Figure 3 As shown, three circular protrusions 23 are evenly distributed on each of the two end surfaces, and the circular protrusions 23 provide an oil discharge gap, forming a smooth oil discharge gap to avoid blockage of the oil discharge hole caused by plane contact;

[0035] A valve body 14 is provided at the lower end of the front choke sleeve 9. The front choke sleeve 9 and the valve body 14 are connected by radial annular riveting, which avoids the risk of the inner hole of the valve body 14 being deformed due to assembly, resulting in the risk of the valve core 13 being stuck, and also improves the assembly consistency; a valve core 13 is provided in the valve body 14 to form a flow valve pair. The valve body 14 and the valve core 13 are made of corrosion-resistant and oxidation-resistant precipitation hardening stainless steel. The pair structure and stainless steel material make the present invention easy to process and grind, with high hardness, good wear resistance, high dimensional accuracy, strong resistance to corrosion from harsh oil products, and long service life; the upper end of the valve core 13 is against the plane of the lower end surface of the front choke sleeve 9, ensuring the accuracy of the initial position of the valve core 13 and improving the consistency of the maximum flow;

[0036] like Figure 4 As shown, a spring 15 is provided at the lower end of the valve core 13. The spring 15 adopts a conical structure. The conical shape increases the spring ring gap, increases the flow area, and avoids the risk of throttling of the spring ring gap at a large flow rate; a spring seat 16 is installed at the lower end of the spring 15, and an oil inlet hole is provided at the center of the spring seat 16. The spring seat 16 is assembled in the valve body 14, and the pre-compression stroke of the spring 15 is adjusted by controlling the assembly depth of the spring seat 16;

[0037] A filter screen 17 is provided at the lower end of the valve body 14 to prevent foreign particles from entering the fuel flow cavity, thereby preventing foreign particles from blocking the engine moving parts and affecting engine combustion; Figure 4 As shown, a buckle 22 is designed at one end of the filter screen 17 , and the buckle 22 is assembled in the slot of the valve body 14 .

[0038] The coil component 7 is placed inside the housing 5 , and a pressing plate 2 and a corrugated gasket 3 are provided between the coil component 7 and the housing 5 .

[0039] Sliding bearings 19 are provided in both the rear choke sleeve 1 and the front choke sleeve 9 to provide movement guidance for the armature 4 and the armature shaft 10, so that the armature 4 and the armature shaft 10 can move flexibly in the oil storage cavity.

[0040] Initially, the armature shaft 10 and the valve core 13 have an idle stroke section of 0.1 mm to avoid large dispersion of the extended end of the armature shaft 10 due to assembly and accumulation of parts size chains, thereby causing poor consistency of the maximum flow rate.

[0041] A flange 11 is installed on the step end face of the front choke sleeve 9, and the flange 11 and the front choke sleeve 9 are connected by interference fitting; two steps are provided on the front choke sleeve 9 to prevent the flange 11 from damaging the next-level assembly surface when assembling downward, causing poor welding between the magnetic isolation ring 6 and the front choke sleeve 9 of the next level; the upper end face of the flange 11 is connected to the lower end of the shell 5.

[0042] A first O-type sealing ring 12 and a second O-type sealing ring 18 are symmetrically provided on the front choke sleeve 9 and the valve body 14 respectively.

[0043] The coil component 7 adopts different interface forms and can be applicable to various connection methods of different host manufacturers.

Claims

1. A fuel metering valve for a diesel engine high-pressure common rail pump resistant to harsh oil products, comprising a rear choke sleeve (1), a housing (5), a coil component (7), a front choke sleeve (9) and a valve body (14), characterized in that: A front choke sleeve (9) and a rear choke sleeve (1) are installed in the coil component (7), and the front choke sleeve (9) and the rear choke sleeve (1) are welded and connected via a magnetic isolation ring (6) to form a sealed oil storage cavity; the rear choke sleeve (1) and the magnetic isolation ring (6) are laser welded and connected at a welding point with a 45° wedge-shaped surface (21); The front choke sleeve (9) adopts a wedge-shaped magnetic isolation angle (20); An armature (4) and an armature shaft (10) are provided between the rear choke sleeve (1) and the front choke sleeve (9), and the armature (4) and the armature shaft (10) are connected by interference fitting; The upper end surface of the front choke sleeve (9) is provided with a gap sheet (8), and the gap sheet (8) can prevent the armature (4) from contacting the front choke sleeve (9), causing the armature (4) to be unable to demagnetize and return in time; the gap sheet (8) is a circular structure, and three circular protrusions (23) are evenly distributed on each of the two end surfaces, and the circular protrusions (23) provide an oil discharge gap; A valve body (14) is provided at the lower end of the front choke sleeve (9), and the front choke sleeve (9) and the valve body (14) are connected by radial annular riveting; a valve core (13) is provided in the valve body (14) to form a flow valve pair, and the valve body (14) and the valve core (13) are made of corrosion-resistant and oxidation-resistant precipitation-hardened stainless steel. The upper end of the valve core (13) abuts against the plane of the lower end surface of the front choke sleeve (9) to ensure that the initial position of the valve core (13) is accurate; a spring (15) is provided at the lower end of the valve core (13), and the spring (15) adopts a conical structure, and the conical shape increases the spring ring gap and the flow area; a spring seat (16) is installed at the lower end of the spring (15), and an oil inlet hole is provided at the center of the spring seat (16); the spring seat (16) is assembled in the valve body (14), and the pre-compression stroke of the spring (15) is adjusted by controlling the assembly depth of the spring seat (16); A filter screen (17) is provided at the lower end of the valve body (14); a buckle (22) is provided at one end of the filter screen (17); the buckle (22) is assembled in a slot of the valve body (14); The coil component (7) is placed inside the housing (5), and a pressing plate (2) and a corrugated gasket (3) are provided between the coil component (7) and the housing (5); The rear choke sleeve (1) and the front choke sleeve (9) are both provided with sliding bearings (19) to provide movement guidance for the armature (4) and the armature shaft (10); the front choke sleeve (9) and the valve body (14) are respectively symmetrically provided with a first O-type sealing ring (12) and a second O-type sealing ring (18).

2. The fuel metering valve for a diesel engine high pressure common rail pump resistant to harsh oil products according to claim 1 is characterized in that: The armature shaft (10) and the valve core (13) initially leave an empty travel section, thereby preventing large dispersion of the extended end of the armature shaft (10) due to assembly and accumulation of part size chains, thereby causing poor consistency in maximum flow.

3. The fuel metering valve for a diesel engine high pressure common rail pump resistant to harsh oil products according to claim 1 is characterized in that: The step end face of the front choke sleeve (9) is provided with a flange (11), and the flange (11) and the front choke sleeve (9) are connected by interference fit; the front choke sleeve (9) is provided with two steps to prevent the flange (11) from damaging the next-level assembly surface when assembling downward, thereby preventing the magnetic isolation ring (6) and the front choke sleeve (9) from being poorly welded together; the upper end face of the flange (11) is connected to the lower end of the housing (5).

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