Pre-combustion chamber jet ignition device for broadening lean burn limit of methanol engine based on flow baffle

Abstract

The invention provides a pre-combustion chamber jet ignition device for broadening the lean burn limit of a methanol engine based on a flow baffle, which comprises a pre-combustion chamber shell, a fuel injector body, a spark plug body and the flow baffle, and is characterized in that the upper part of the pre-combustion chamber shell is provided with a fuel injector mounting groove for mounting the fuel injector body and a spark plug mounting groove for mounting the spark plug body; a primary jet flow cavity is formed in the middle, and a secondary jet flow cavity is formed in the lower part; a jet hole is formed in the bottom end of the second-stage jet cavity and communicates with a main combustion chamber of the engine. The combustor is used for spraying high-energy flames to the main combustion chamber so as to ignite combustible mixed gas in the main combustion chamber; the flow baffle is mounted at the internal joint of the first-stage jet flow cavity and the second-stage jet flow cavity; the pre-combustion chamber shell is fixed to an engine cylinder cover through a pressing plate and bolts. The energy of combustion flames generated by the pre-combustion chamber is improved, the injection duration is prolonged, the methanol lean-burn limit is finally widened, and the cold start problem of a methanol engine can be solved.

Description

Technical Field

[0001] The present invention belongs to the field of internal combustion engines, and particularly relates to a pre-chamber jet ignition device for broadening the lean burn limit of a methanol engine based on a baffle plate. Background Art

[0002] As the main energy source for human development, petroleum has limited reserves and produces pollutants during use. Therefore, an increasing number of researchers globally are committed to developing alternative fuels such as low-carbon and zero-carbon fuels. As one of the representative alternative fuels, methanol has a very wide range of sources and can be produced from various raw materials such as coal, natural gas, and biomass. With the development of technology, the characteristics of low production cost, convenient storage, and transportation of methanol have attracted wide attention in the field of internal combustion engines.

[0003] Methanol has a low cetane number and properties such as low vapor pressure and high latent heat of vaporization. When the engine starts, the heat absorbed by methanol fuel is about 8 times that of gasoline, while the evaporation amount of methanol is only 1 / 4 of that of gasoline. As a result, the concentration of the methanol mixture in the main combustion chamber of the engine fails to meet the requirements for spark ignition, which leads to misfire problems in the methanol engine under low load and lean burn conditions. Additionally, there are difficulties in cold starting in low-temperature environments. With the progress of modern science and technology, the pre-chamber jet ignition technology capable of solving the above problems has emerged.

[0004] The pre-chamber is an important component of the pre-chamber jet ignition technology. The combustion process of the combustible mixture in the pre-chamber will directly affect the generation of high-energy active substances in the pre-chamber and the process of spraying them into the main combustion chamber. The energy of high-energy active substances generated by the existing pre-chambers and their injection time are limited and insufficient to broaden the lean burn limit of methanol. Therefore, how to broaden the lean burn limit of methanol in the engine and cold start has become an urgent problem to be solved. Summary of the Invention

[0005] In view of this, the present invention aims to propose a pre-chamber jet ignition device for broadening the lean burn limit of a methanol engine based on a baffle plate to increase the energy of the combustion flame generated by the pre-chamber and extend the injection duration, ultimately broadening the lean burn limit of methanol and being able to solve the cold start problem of the methanol engine.

[0006] To achieve the above object, the technical solution of the present invention is realized as follows: A pre-chamber jet ignition device for broadening the lean burn limit of a methanol engine based on a baffle plate includes a pre-chamber housing, an injector body, a spark plug body, and a baffle plate. The upper part of the pre-chamber housing is provided with an injector installation groove for installing the injector body and a spark plug installation groove for installing the spark plug body. The middle part forms a primary jet cavity, and the lower part forms a secondary jet cavity; The bottom end of the secondary jet cavity is provided with jet holes, and the jet holes are communicated with the main combustion chamber of the engine; it is used to inject high-energy flame into the main combustion chamber, thereby igniting the combustible mixture in the main combustion chamber; The baffle is installed at the internal connection of the primary jet cavity and the secondary jet cavity; the pre-combustion chamber housing is fixed to the engine cylinder head through a pressing plate and bolts.

[0007] Furthermore, the upper end of the fuel injector body is connected to a fuel pipe, which is used to supply methanol fuel to the fuel injector. The fuel injector body controls the injection frequency and injection volume of fuel sprayed into the pre-combustion chamber cavity through an electronic control system, thereby forming a combustible mixture in the pre-combustion chamber cavity; The spark plug body controls the energization and de-energization moments of the spark plug body through an electronic control system, thereby controlling the moment of igniting the combustible mixture in the pre-combustion chamber.

[0008] Furthermore, the baffle is a conical curved surface structure with holes, and the diameter of the curved surface gradually decreases from top to bottom; the baffle divides the pre-combustion chamber cavity into a primary jet cavity and a secondary jet cavity. There are baffle holes on the small end surface of the baffle, and the baffle holes communicate the primary jet cavity and the secondary jet cavity; The spark plug body is used to ignite the combustible mixture in the primary jet cavity, forming a flame that spreads around. Among them, the vertically downward jet flame propagates in the secondary jet cavity and is sprayed into the main combustion chamber through the jet holes; The vertically downward propagating flame ignites the combustible mixture in the secondary jet cavity, forming a high-temperature diffusion flame. The upper end of this flame is blocked by the high-pressure gas and the baffle in the primary jet cavity, forming a local disturbance flame. The disturbance flame cannot propagate upward. Therefore, the high-temperature diffusion flame can only pass through the jet holes downward into the main combustion chamber, ultimately realizing the strengthening of the jet flame ejected from the pre-combustion chamber.

[0009] Furthermore, the aperture of the baffle hole is 2-4 mm; the center line of the baffle hole coincides with the center line of the pre-combustion chamber cavity.

[0010] Furthermore, both the pre-combustion chamber housing and the baffle are made of steel.

[0011] Furthermore, the volume ratio range of the primary jet cavity and the secondary jet cavity is 1:1 - 2:1.

[0012] Compared with the prior art, the pre-combustion chamber jet ignition device based on a baffle to broaden the lean burn limit of a methanol engine of the present invention has the following advantages: (1) A pre-chamber jet ignition device for widening the lean burn limit of a methanol engine based on a baffle. The baffle is a conical surface with holes, which can divide the pre-chamber cavity into two parts: a primary jet cavity and a secondary jet cavity. The flame propagating vertically downward in the primary jet cavity can shorten the ignition delay of the combustible mixture in the main combustion chamber by the pre-chamber.

[0013] (2) A pre-chamber jet ignition device for widening the lean burn limit of a methanol engine based on a baffle. The combustion of the combustible mixture in the secondary jet cavity can further increase the energy of the pre-chamber jet flame, thereby improving the cold start performance of the methanol engine and widening the lean burn limit. Description of the Drawings

[0014] The drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 Schematic diagram of a pre-chamber jet ignition device for widening the lean burn limit of a methanol engine based on a baffle according to an embodiment of the present invention; Figure 2 Cross-sectional view of a pre-chamber jet ignition device for widening the lean burn limit of a methanol engine based on a baffle according to an embodiment of the present invention; Figure 3 Schematic diagram of the baffle according to an embodiment of the present invention.

[0015] Description of the reference numerals in the drawings: 1. Pre-chamber housing; 101. Injector mounting groove; 102. Spark plug mounting groove; 103. Jet hole; 2. Injector body; 201. Injector nozzle hole; 3. Spark plug body; 301. Spark plug electrode; 4. Baffle; 401. Baffle hole; 5. Primary jet cavity; 6. Secondary jet cavity; 701. Vertically propagating flame; 702. Disturbing flame; 703. Jet flame. Detailed Embodiments

[0016] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0017] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0018] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific circumstances.

[0019] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0020] A pre-chamber jet ignition device for broadening the lean burn limit of a methanol engine based on a baffle 4, as Figures 1-3 shown, includes a pre-chamber housing 1, an injector body 2, a spark plug body 3, and a baffle 4. An injector mounting groove 101 for mounting the injector body 2 and a spark plug mounting groove 102 for mounting the spark plug body 3 are provided in the upper part of the pre-chamber housing 1. A primary jet chamber 5 is formed in the middle part, and a secondary jet chamber 6 is formed in the lower part; A jet hole 103 is provided at the bottom end of the secondary jet chamber 6, and the jet hole 103 communicates with the main combustion chamber of the engine; it is used to inject high-energy flame into the main combustion chamber, thereby igniting the combustible mixture in the main combustion chamber; The baffle 4 is installed at the internal connection of the primary jet chamber 5 and the secondary jet chamber 6; the pre-chamber housing 1 is fixed to the engine cylinder head through a pressing plate and bolts.

[0021] Preferably, an injector hole 201 is provided on the injector body 2. The upper end of the injector body 2 is connected to a fuel pipe, which is used to supply methanol fuel to the injector. The injector body 2 is controlled by a circuit control system to control the injection frequency and injection volume of fuel into the pre-chamber cavity, thereby forming a combustible mixture in the pre-chamber cavity; The spark plug body 3 is provided with a spark plug motor 301. The spark plug body 3 controls the energization and de-energization times of the spark plug body 3 through a circuit control system, thereby controlling the time to ignite the combustible mixture in the pre-chamber.

[0022] Preferably, the baffle 4 is a conical curved surface structure with holes, and the diameter of the curved surface gradually decreases from top to bottom; the baffle 4 divides the pre-chamber cavity into a primary jet cavity 5 and a secondary jet cavity 6. A baffle hole 401 is provided on the small end surface of the baffle 4, and the baffle hole 401 communicates the primary jet cavity and the secondary jet cavity 6; The spark plug body 3 is used to ignite the combustible mixture in the primary jet cavity 5 to form a flame that spreads around. Among them, the flame that jets vertically downward propagates in the secondary jet cavity 6 and is sprayed into the main combustion chamber through the jet hole 103; The vertically propagating flame 701 that propagates vertically downward ignites the combustible mixture in the secondary jet cavity 6 to form a high-temperature diffusion flame. The upper end of this flame is blocked by the high-pressure gas in the primary jet cavity 5 and the baffle 4 to form a local disturbance flame 702. The disturbance flame 702 cannot propagate upward. Therefore, the high-temperature diffusion flame can only pass downward through the jet hole 103 into the main combustion chamber, finally realizing the strengthening of the jet flame 703 ejected from the pre-chamber.

[0023] Preferably, the aperture of the baffle hole 401 is 2-4 mm; a smaller aperture can accelerate the flow rate of the flame when passing through, forming a high-energy jet flame 703, thereby enhancing the penetration and ignition ability of the lean mixture in the main combustion chamber; too large an aperture will cause the pressure in the primary jet cavity 5 to be released too quickly, reducing the combustion intensity of the secondary jet cavity 6; while too small an aperture may hinder the flame propagation. The aperture range of 2-4 mm can ensure the efficient transmission of the flame while maintaining the pressure gradient between the two jet cavities, ensuring the full combustion of the mixture in the secondary jet cavity 6; The center line of the baffle hole 401 coincides with the center line of the pre-chamber cavity. The alignment of the center lines ensures that the flame propagates axially symmetrically in the pre-chamber, reducing the turbulent disturbance or energy loss caused by deflection, making the flame more concentrated and evenly sprayed into the main combustion chamber; the symmetric structure can prevent the flame from deflecting or locally extinguishing in the secondary jet cavity 6, ensuring that the high-temperature flame continuously passes downward through the jet hole 103 to strengthen the ignition effect on the mixture in the main combustion chamber.

[0024] Preferably, both the pre-chamber housing 1 and the baffle 4 are made of steel material.

[0025] Preferably, the volume ratio range of the primary jet chamber 5 and the secondary jet chamber 6 is 1:1 - 2:1. Within this range, it is beneficial for the flame to spread rapidly in the pre-combustion chamber. After the flame in the primary jet chamber 5 is ignited, it quickly spreads to the secondary jet chamber 6. Due to the reasonable setting of the volume ratio, the propagation speed of the flame in the secondary jet chamber 6 is increased, and it can pass through the jet holes 103 into the main combustion chamber more quickly, thereby shortening the ignition delay time and improving the combustion efficiency.

[0026] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A pre-chamber jet ignition device for widening the lean combustion limit of a methanol engine based on a baffle plate, characterized in that: It includes a pre - combustion chamber housing, an injector body, a spark plug body, and a baffle. An injector mounting groove for mounting the injector body and a spark plug mounting groove for mounting the spark plug body are provided in the upper part of the pre - combustion chamber housing. A primary jet chamber is formed in the middle part, and a secondary jet chamber is formed in the lower part. A jet hole is provided at the bottom end of the secondary jet chamber, and the jet hole communicates with the main combustion chamber of the engine; it is used to inject high - energy flame into the main combustion chamber, thereby igniting the combustible mixture in the main combustion chamber. The baffle is installed at the internal connection of the primary jet chamber and the secondary jet chamber; the pre - combustion chamber housing is fixed to the engine cylinder head through a pressing plate and bolts.

2. The pre-chamber jet ignition device for widening the lean burn limit of a methanol engine based on a baffle according to claim 1, characterized in that: The upper end of the injector body is connected to a fuel pipe, which is used to supply methanol fuel to the injector. The injector body controls the frequency and injection volume of fuel sprayed into the pre - combustion chamber cavity through a circuit control system, thereby forming a combustible mixture in the pre - combustion chamber cavity. The spark plug body controls the energization and de - energization moments of the spark plug body through a circuit control system, thereby controlling the moment of igniting the combustible mixture in the pre - combustion chamber.

3. A pre-chamber jet ignition device for widening the lean burn limit of a methanol engine based on a baffle plate according to claim 1, characterized in that: The baffle is a conical curved surface structure with holes, and the diameter of the curved surface gradually decreases from top to bottom; the baffle divides the pre - combustion chamber cavity into a primary jet chamber and a secondary jet chamber. A baffle hole is provided on the small end surface of the baffle, and the baffle hole connects the primary jet chamber and the secondary jet chamber. The spark plug body is used to ignite the combustible mixture in the primary jet chamber, forming a flame that spreads around. Among them, the flame jetting vertically downward propagates in the secondary jet chamber and is sprayed into the main combustion chamber through the jet hole. The vertically propagating flame jetting vertically downward ignites the combustible mixture in the secondary jet chamber, forming a high - temperature diffusion flame. The upper end of this flame is blocked by the high - pressure gas in the primary jet chamber and the baffle, forming a local disturbance flame. The disturbance flame cannot propagate upward. Therefore, the high - temperature diffusion flame can only pass through the jet hole downward into the main combustion chamber, finally realizing the strengthening of the jet flame ejected from the pre - combustion chamber.

4. A pre-chamber jet ignition device for widening the lean burn limit of a methanol engine based on a baffle plate according to claim 3, characterized in that: The aperture of the baffle hole is 2 - 4 mm; the center line of the baffle hole coincides with the center line of the pre - combustion chamber cavity.

5. A pre-chamber jet ignition device for widening the lean burn limit of a methanol engine based on a baffle plate according to claim 4, characterized in that: Both the pre - combustion chamber housing and the baffle are made of steel materials.

6. A pre-chamber jet ignition device for widening the lean burn limit of a methanol engine based on a baffle plate according to claim 1, characterized in that: The volume ratio range of the primary jet chamber and the secondary jet chamber is 1:1 - 2:1.

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