Passive pre-combustion chamber spark plug adaptive to middle fuel injection
By designing a passive pre-combustion chamber spark plug adapted to centrally located fuel injection, and adopting an integral structure and spatially distributed jet orifices, the problem of uneven distribution of jet flame in centrally located fuel injection engines is solved, improving combustion stability and fuel economy, and is suitable for gasoline engines.
Patent Information
- Application Number
- CN202422170775.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-05
- Publication Date
- 2025-10-17
- Estimated Expiration
- 2034-09-05
AI Technical Summary
Existing passive pre-chamber spark plugs in mid-mounted fuel injection engines have the problem of uneven jet flame distribution, resulting in unstable combustion and poor fuel economy.
A passive pre-combustion chamber spark plug adapted for central fuel injection was designed. It adopts an integral structure, including a metal shell, ceramic body, inner gasket, center electrode assembly, built-in resistor, wiring screw, outer gasket, side electrode assembly and pre-combustion chamber cap. The side electrode assembly consists of two opposing side electrodes and a support ring. The jet holes are spatially distributed on the pre-combustion chamber cap. The center lines of the three sets of jet holes intersect the center line of the spark plug at different points, so as to achieve uniform flame distribution in the combustion chamber.
It achieves uniform flame distribution under centrally located fuel injection conditions, improving combustion stability and fuel economy. It does not require modification of the engine cylinder head and is simple to manufacture in large quantities.
Smart Images
Figure CN223451390U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to the technical field of spark plug, especially relates to a passive precombustion chamber spark plug suitable for middle placement oil injection. BACKGROUND
[0002] The ignition point of gasoline is high, and the compression ignition mode cannot be used to realize combustion when being applied to an automobile. Therefore, in order to realize stable combustion of gasoline, a spark plug must be used. The spark plug is an essential key component for a gasoline engine.
[0003] Research shows that the lean burn technology has great potential in energy saving and emission reduction of gasoline engines. However, lean combustion will reduce the ignition and combustion speed, and the low combustion speed will greatly delay the combustion phase and increase the combustion cycle variation.
[0004] Research shows that stable lean combustion needs to increase the ignition energy and prolong the spark duration. In the currently developed lean gasoline engine, combustion instability is one of the main problems. In order to solve the problem of combustion instability under lean combustion conditions, researchers have developed new high-energy and high-efficiency ignition technologies, such as laser ignition technology, multi-spark ignition technology, multi-center electrode ignition technology, and precombustion chamber ignition technology. Among them, the precombustion chamber ignition technology has attracted much attention in recent years.
[0005] At present, foreign countries have tried to apply the precombustion chamber ignition technology to conventional gasoline engines and have obtained some results. Domestic researchers are trying to apply the precombustion chamber ignition technology to existing engines. However, the passive precombustion chamber spark plug with conventional jet holes uniformly distributed at the same height and along the spark plug axis has a contradiction between the need for uniform distribution of precombustion jet flame in the combustion chamber and the condition of being arranged at a certain angle with the center axis of the combustion chamber. There is a problem that the passive precombustion jet flame cannot be uniformly distributed in the combustion chamber of the middle placement oil injection engine. UTILITY MODEL CONTENTS
[0006] The utility model discloses a passive precombustion chamber spark plug of adapting to middle injection, and the passive precombustion chamber spark plug structure includes: the metal shell with external thread matched with the engine cylinder cover, the coaxial and hollow ceramic body fixed in the metal shell, the inner gasket of metal material between the metal shell and the hollow ceramic body for sealing, the center electrode assembly fixed in the hollow ceramic body firing portion coaxial with the hollow ceramic body, the built-in resistance body fixed above the center electrode assembly coaxial with the hollow ceramic body for electromagnetic radiation inhibition, the wiring screw rod connected with the ignition coil high voltage output end fixed above the resistance body coaxial with the hollow ceramic body, the outer gasket installed at the metal shell flange for realizing the gas sealing function between the spark plug and the cylinder cover, the side electrode assembly fixed on the metal shell inner wall coaxial with the metal shell and forming the ignition gap with the center electrode assembly, the precombustion chamber cap coaxial with the metal shell and welded together with the metal shell, and the multiple jet holes arranged on the precombustion chamber cap for realizing the exchange of internal and external substances and energy in the precombustion chamber in spatial distribution.
[0007] Further, the passive precombustion chamber spark plug is a whole type passive precombustion chamber spark plug, which can be directly replaced with the traditional spark plug and does not need to make any change to the engine cylinder cover.
[0008] Further, the side electrode assembly is composed of two opposite side electrodes and a side electrode support ring.
[0009] Further, the side electrode support ring is fixed on the metal shell inner wall.
[0010] Further, the multiple jet holes are spatially distributed on the precombustion chamber cap, and the number of the multiple jet holes is six, which can be divided into three groups.
[0011] Further, the intersection positions of the center lines of the two jet holes in each group of the three groups of jet holes with the center line of the passive precombustion chamber spark plug are different.
[0012] Further, the center lines of the jet holes in any group (each group of jet holes has two jet holes) of the three groups of precombustion chamber holes intersect with the center line of the passive precombustion chamber spark plug, but the intersection points of the three groups are different in position on the center line of the passive precombustion chamber spark plug.
[0013] Further, the angles between the center lines of the three groups of precombustion chamber jet holes and the center line of the passive precombustion chamber spark plug are different.
[0014] Further, the diameters of the plurality of jet holes located at any one side of the intake side and the exhaust side of the engine are the same.
[0015] Compared with the prior art, the utility model has the beneficial effects mainly shown in the following:
[0016] 1. The passive pre-chamber spark plug of the utility model is integrally designed, compact in structure, and can be directly used to replace the conventional spark plug without changing the engine cylinder head.
[0017] 2. The passive pre-chamber spark plug of the utility model uses a supporting ring to fix the side electrode, and this method is simple in process and easy to realize mass production.
[0018] 3. The passive pre-chamber spark plug of the utility model uses a double-side electrode mode to cope with the complex oil-gas mixture flow field and concentration field inside the pre-chamber and realize reliable ignition.
[0019] 4. The pre-chamber jet hole of the passive pre-chamber spark plug of the utility model is designed in space, and can realize that the direction of the jet hole of the pre-chamber spark plug under the condition of middle oil injection is just able to compensate for the inclination angle of the pre-chamber spark plug under the condition of middle oil injection, so that the uniform distribution of the pre-chamber jet flame in the combustion chamber is realized, thereby laying a foundation for improving the combustion stability and fuel economy of the pre-chamber jet ignition engine. BRIEF DESCRIPTION OF DRAWINGS
[0020] Figure 1 It is an outline drawing of the passive pre-chamber spark plug of the utility model.
[0021] Figure 2 It is an internal structure drawing of the passive pre-chamber spark plug of the utility model.
[0022] Figure 3 It is a structure schematic view of the side electrode assembly in the utility model.
[0023] Figure 4 It is a key size schematic view of the side electrode assembly.
[0024] Figure 5 It is a structure schematic view of the pre-chamber cap in the utility model.
[0025] Figure 6 It is a coordinate system schematic view of the center line of the pre-chamber cap in the utility model.
[0026] Figure 7 It is an F-F cross section schematic view of the pre-chamber cap.
[0027] Figure 8 It is a G-G cross section schematic view of the pre-chamber cap.
[0028] Figure 9 It is an H-H cross section schematic view of the pre-chamber cap.
[0029] Figure 10 Figure 1 is a schematic diagram of the position relationship between the jet hole and the engine intake and exhaust.
[0030] Figure 11 Figure 2 is a schematic diagram of the distribution of the jet flame bundle of the middle oil injection pre-chamber in the combustion chamber.
[0031] Figure 12 Figure 3 is a schematic diagram of the position relationship between the passive pre-chamber spark plug of the middle oil injection and the engine.
[0032] In the figure, 1 is a metal shell, 2 is a ceramic body, 3 is an inner gasket, 4 is a center electrode assembly, 5 is a resistance body, 6 is a wiring screw, 7 is an outer gasket, 8 is a side electrode assembly, 81 is a side electrode, 82 is a side electrode support ring, 9 is a pre-chamber cap, 10 is a jet hole, 11 is a pre-chamber, and 12 is an ignition gap.
[0033] In the figure, 21 is an intake valve, 22 is a direct injection oil injector, 23 is an exhaust valve, 24 is a jet flame bundle, 25 is a cylinder pressure sensor, 26 is a cylinder head, 27 is a cylinder block, 28 is a connecting rod, and 29 is a piston. DETAILED DESCRIPTION
[0034] The passive pre-chamber spark plug adapted to the middle oil injection of the utility model will be described in more detail below in connection with the schematic diagram, wherein the preferred embodiments of the utility model are represented, and it should be understood that the utility model described herein can be modified by those skilled in the art, and the advantageous effects of the utility model can still be achieved, therefore, the following description should be understood as the extensive knowledge of those skilled in the art, and not as the limitation of the utility model.
[0035] The passive pre-chamber spark plug adapted to the middle oil injection of the utility model has the appearance as shown in Figure 1 As can be seen from the figure, it is a whole passive pre-chamber spark plug. Figure 2 The structure of the passive pre-chamber spark plug of the utility model is shown, and specifically comprises: containing a metal shell 1, a ceramic body 2, an inner gasket 3, a center electrode assembly 4, an embedded resistance body 5, a wiring screw 6, an outer gasket 7, a side electrode assembly 8, a pre-chamber cap 9, and a jet hole 10. The metal shell 1, the ceramic body 2, and the pre-chamber cap 9 jointly form a pre-chamber 11. The center electrode assembly 4 and the side electrode assembly 8 form an ignition gap 12, and the ignition gap 12 is located inside the pre-chamber 11.
[0036] The passive pre-chamber spark plug of the utility model adopts the design of the side electrode assembly type, as shown in Figure 3The side electrode assembly includes two side electrodes 82 and a side electrode support ring 81. In the production of the side electrode assembly, first, two side electrode positioning holes with a diameter Φ1 are machined on the side electrode support ring 81, then the two side electrodes 82 are fixed on the two positioning holes of the support ring respectively, and then the side electrode support ring 81 is fixed on the inner wall of the metal shell 1 by laser welding. The key dimensions of the side electrode assembly are as shown in the table below. Figure 4 The outer diameter of the pre-chamber cap 9 is Φ8, the inner diameter is Φ6.5, and the height is 2.5.
[0037] The outer shape of the pre-chamber cap 9 is as shown in the figure. Figure 5 As can be seen from the figure, the outer shape of the pre-chamber cap 9 is curved, and the jet holes 10 are distributed on the surface of the pre-chamber cap 9 in a spatial distribution pattern. In order to clearly express the characteristics of the jet holes on the pre-chamber cap 9, a coordinate system passing through the center line of the pre-chamber cap is established, and reference is made to Figure 6 , three groups of jet holes are obtained as F-F, G-G and H-H. With the F-F direction, G-G direction and H-H direction as the reference, the pre-chamber cap 9 is cut in the direction of F-F, G-G and H-H, and the detailed characteristics of the three groups of jet holes on the pre-chamber cap 9 can be obtained.
[0038] The first group of jet hole cross-sectional characteristics obtained by cutting in the direction of F-F are as shown in the figure. Figure 7 As can be seen from Figure 7 , the main characteristics of this group of jet holes are: the hole diameter of the jet hole is Φ1.2, the center lines of the two jet holes intersect with the center line of the pre-chamber spark plug and the intersection point coincides, the angle between the center line of the jet hole and the center line of the pre-chamber spark plug is 94°, and the distance from the intersection point of the center line of the jet hole to the outer contour low surface of the pre-chamber firing part is 2.45.
[0039] The second group of jet hole cross-sectional characteristics obtained by cutting in the direction of G-G are as shown in the figure. Figure 8 As can be seen from Figure 8 , the main characteristics of this group of jet holes are: the hole diameter of the jet hole is Φ1.2, the center lines of the two jet holes intersect with the center line of the pre-chamber spark plug and the intersection point coincides, the angle between the center line of the jet hole and the center line of the pre-chamber spark plug is 67°, and the distance from the intersection point of the center line of the jet hole to the outer contour low surface of the pre-chamber firing part is 3.9.
[0040] The third group of jet hole cross-sectional characteristics obtained by cutting in the direction of H-H are as shown in the figure. Figure 9 As can be seen from Figure 9 , the main characteristics of this group of jet holes are: the hole diameter of the jet hole is Φ1.2, the center lines of the two jet holes intersect with the center line of the pre-chamber spark plug and the intersection point coincides, the angle between the center line of the jet hole and the center line of the pre-chamber spark plug is 55°, and the distance from the intersection point of the center line of the jet hole to the outer contour low surface of the pre-chamber firing part is 3.85.
[0041] The passive pre-chamber spark plug and engine of the present patent, the relationship between the jet hole 10 and the intake and exhaust of the engine is shown in Figure 10 . Figure 10 The intake valve 21, the fuel injector 22, and the cylinder pressure sensor 25 can be seen. Figure 10 It can be seen that the fuel injector 22 is designed as a center injection, and the pre-chamber spark plug is arranged at an angle with the center line of the cylinder to adapt to the center injection and match the combustion chamber. As shown in Figure 10 , the cross section along the center line of the fuel injector-pre-chamber spark plug, the cross section passes through the center line of the engine cylinder. In use, in order to ensure more thorough scavenging in the pre-chamber, the intake flow passes through the main combustion chamber and the pre-chamber in the direction from the intake valve to the exhaust valve.
[0042] The schematic diagram of the center injection pre-chamber flame bundle of the present patent is shown in Figure 11 . Figure 11 The intake valve 21, the fuel injector 22, the exhaust valve 23, the pre-chamber jet flame bundle 24, and the cylinder pressure sensor 25 can be seen. Figure 11 It can be seen that for the center injection design, the space design of the pre-chamber jet hole on the pre-chamber cap can compensate for the influence of the inclined installation of the spark plug under the condition of center injection, and can realize the uniform distribution of the jet flame bundle in the combustion chamber under the condition that the pre-chamber spark plug is arranged at an angle with the cylinder axis.
[0043] The center injection passive pre-chamber spark plug and engine of the present patent, as shown in Figure 12 , is a schematic diagram of the assembly of the pre-chamber spark plug and the engine. In the figure, 21 is an intake valve, 22 is a fuel injector, 23 is an exhaust valve, 24 is a jet flame bundle, 26 is a cylinder head, 27 is a cylinder block, 28 is a connecting rod, and 29 is a piston. The cylinder block and the cylinder head, the fuel injector, the pre-chamber spark plug, and the intake valve, the exhaust valve, and the fuel injector together form a combustion chamber of the engine. During engine operation, the combustion chamber and the outside exchange materials through the intake valve 21, the exhaust valve 23, and the fuel injector 22, and the heat energy generated by fuel combustion is converted into mechanical energy through the piston 29, and the reciprocating motion of the piston is converted into the rotary motion of the crankshaft through the connecting rod 28, realizing the leap of heat energy generated by fuel combustion into mechanical energy.
[0044] The pre-chamber spark plug and the engine cylinder head are designed together to realize the positioning of the side electrode of the spark plug. The improvement of lean burn fuel economy is essentially to form a dense mixture around the center electrode assembly 4 of the spark plug, and to use a relatively lean combustible mixture at a position away from the center electrode assembly 4, that is, the in-cylinder combustible mixture is distributed according to the concentration gradient. At the same time, considering that the flow field state in the cylinder has many uncertainties during engine operation, therefore, the side electrode orientation technology of the spark plug is adopted, which is helpful to improve the ignition stability in the lean burn environment.
[0045] The above are only preferred embodiments of the present application, and do not have any limiting effect on the present application. Any person skilled in the art, without departing from the technical solution of the present application, makes any form of equivalent replacement or modification of the technical solution and technical content disclosed by the present application, and the change belongs to the content of the technical solution of the present application, and still belongs to the protection scope of the present application.
Claims
1. A passive pre-combustion chamber spark plug adapted for center fuel injection, characterized in that: The invention comprises a metal shell fixed to the engine cylinder head, a ceramic body extending into the top end of the metal shell, and a pre-combustion chamber cap fixed to the bottom end thereof, wherein the metal shell, the ceramic body and the pre-combustion chamber cap are coaxially arranged, the bottom end of the pre-combustion chamber cap extending out of the bottom end of the metal shell, and a pre-combustion chamber is formed between the metal shell, the ceramic body and the pre-combustion chamber cap; A side electrode assembly is fixed between the pre-combustion chamber cap and the ceramic body. A central electrode assembly for ignition is coaxially arranged inside the ceramic body. The bottom end of the central electrode assembly extends out of the ceramic body and into the side electrode assembly, forming an ignition gap with the side electrode assembly. The ignition gap is located inside the pre-combustion chamber. A plurality of jet holes for evenly distributing the jet flame in the combustion chamber are distributed in the space of the pre-combustion chamber cap, and the plurality of jet holes are communicated with the pre-combustion chamber.
2. The passive pre-combustion chamber spark plug adapted for center fuel injection according to claim 1, characterized in that: The plurality of jet holes are divided into three groups, each group of the jet holes has two jet holes, and the two jet holes in each group are symmetrically arranged in a plane passing through the central axis of the passive pre-combustion chamber spark plug.
3. The passive pre-combustion chamber spark plug adapted for center fuel injection according to claim 2, characterized in that: In the three groups of jet holes, the intersection positions of the center lines of the two jet holes in each group and the center line of the passive pre-combustion chamber spark plug are all different.
4. The passive pre-combustion chamber spark plug adapted for center fuel injection according to claim 2, characterized in that: In the three groups of jet holes, the included angles between the center lines of the two jet holes in each group and the center line of the passive pre-combustion chamber spark plug are all unequal.
5. The passive pre-combustion chamber spark plug adapted for center fuel injection according to claim 1, characterized in that: The side electrode assembly includes a side electrode support ring and a side electrode. There are two side electrodes. The side electrode support ring is fixed on the inner wall of the metal shell. The two side electrodes are relatively fixed to the inner wall of the side electrode support ring, and the two side electrodes are perpendicular to the air intake direction.
6. The passive pre-combustion chamber spark plug adapted for center fuel injection according to claim 1, characterized in that: The diameters of the plurality of jet holes located on either the intake side or the exhaust side of the engine are the same.
7. The passive pre-combustion chamber spark plug adapted for center fuel injection according to claim 1, characterized in that: It also includes a built-in resistor and a wiring screw arranged inside the ceramic body and coaxially with the central electrode assembly. The built-in resistor is arranged above the central electrode assembly to suppress electromagnetic radiation; the wiring screw is arranged above the built-in resistor, and the top end of the wiring screw extends out of the top end of the ceramic body and is connected to the high-voltage output end of the ignition coil.
8. The passive pre-combustion chamber spark plug adapted for center fuel injection according to claim 1, characterized in that: An inner gasket made of metal material is provided between the metal shell and the ceramic body for sealing.
9. The passive pre-combustion chamber spark plug adapted for center fuel injection according to claim 1, characterized in that: The metal shell is provided with an outer gasket at the flange for achieving sealing between the passive pre-combustion chamber spark plug and the engine cylinder head.