Direct injection mixed intake structure of LNG gas engine

Abstract

This invention discloses a direct injection mixing intake structure for an LNG gas engine, comprising a multi-point injection module. The multi-point injection module includes a guide vane, an intake manifold, a mixer, and nozzles. The intake manifold is connected to the guide vane, the mixer is located in the intake channel of the intake manifold, and the nozzles are mounted on the guide vane and connected to the mixer. Several sets of guide vanes from the multi-point injection modules are sequentially connected in series to form a gas passage. The nozzles of each set of multi-point injection modules inject the gas from the gas passage into the mixer of their respective multi-point injection module, where it mixes with air supplied to the intake manifold of that multi-point injection module to form a mixed gas. Each set of multi-point injection modules corresponds one-to-one with each cylinder of the gas engine, effectively ensuring that the mixed gas drawn into each cylinder maintains a uniform and stable air-fuel ratio.

Description

[Technical Field]

[0001] This invention relates to the technical field of gas internal combustion engines, and in particular to the technical field of a direct injection mixed intake structure for an LNG gas engine. [Background Technology]

[0002] A gas engine is a device that generates kinetic energy by burning combustible gases such as natural gas and hydrogen. Depending on the method of natural gas storage, gas engines that burn natural gas can be divided into LNG (Liquefied Natural Gas) engines and CNG (Compressed Natural Gas) engines. In recent years, gas engines using natural gas as fuel have gradually become a new focus in fields such as shipping, oilfield drilling power generation, and mining. Compared to traditional diesel engines, they are cheaper and more environmentally friendly (reducing CO2 emissions by approximately 20%, CO by 97%, hydrocarbons by approximately 72%, and nitrogen oxides by approximately 30% in exhaust gases, and are virtually free of harmful substances such as lead, sulfides, and benzene). With the national need for carbon peaking and energy conservation and emission reduction, and the tight global oil supply, actively promoting the conversion from oil to gas is of great significance to my country's low-carbon economy.

[0003] For existing gas engines that burn natural gas, they typically employ, for example... Figure 1 The diagram shows a main intake manifold. (See attached image.) Figure 1 During operation, air enters the gas manifold 8 along direction A, while the common rail injection 6 simultaneously injects natural gas along direction B into the gas manifold 8, where it mixes with the air. This mixture is then drawn into and burned in each cylinder 7. However, because the distances between the air and natural gas inlets of the gas manifold 8 and the outlets of the mixed gas are not uniform, the amounts of air and natural gas drawn into each cylinder 7 are not equal (i.e., the air-fuel ratio is unstable), resulting in different combustion temperatures. This uneven combustion can easily lead to cylinder knocking, cylinder scoring, or cylinder explosion. Furthermore, natural gas itself requires a relatively high air-fuel ratio (natural gas: air = 1:17) to achieve complete combustion. Compared to diesel, natural gas, in addition to its higher air-fuel ratio requirement, also suffers from higher ignition points, lower flame propagation rates under lean-burn conditions, unstable combustion, large cycle variations, lower combustion volume, and lower thermal efficiency. These problems collectively hinder the conversion of oil to gas in shipbuilding, oilfield drilling power generation, and mining industries, and urgently need to be addressed. [Summary of the Invention]

[0004] The purpose of this invention is to solve the problems in the prior art and to propose a direct injection mixing intake structure for an LNG gas engine, which can effectively ensure that the mixed gas drawn into each cylinder maintains a uniform and stable air-fuel ratio.

[0005] To achieve the above objectives, this invention proposes a direct injection mixing intake structure for an LNG gas engine, comprising a multi-point injection module. The multi-point injection module includes a guide vane, an intake manifold, a mixer, and nozzles. The intake manifold is connected to the guide vane, the mixer is located within the intake channel of the intake manifold, and the nozzles are mounted on the guide vane and connected to the mixer. Several groups of guide vanes from the multi-point injection modules are sequentially connected in series to form a gas passage. The nozzles of each group of multi-point injection modules inject the gas from the gas passage into the mixer of their respective multi-point injection module, where it mixes with air supplied to the intake manifold of that multi-point injection module to form a mixed gas. Each group of multi-point injection modules corresponds one-to-one with each cylinder of the gas engine, and each cylinder automatically draws in the mixed gas generated by its corresponding multi-point injection module.

[0006] Preferably, the gas guide includes a support base and a conduit. The support base is sleeved outside the conduit and has several mounting ports for fixing the nozzles. Each mounting port is connected to the pipe body channel of the conduit. The conduits of the gas guides of each multi-point injection module are connected in sequence, and the pipe body channels are connected in series to form a gas passage.

[0007] Furthermore, the free end of the conduit located at one end of the gas passage is sealed by a sealing plate, and a connecting pipe is installed at the free end of the conduit located at the other end of the gas passage.

[0008] Preferably, an intake channel is formed between the two opposite sidewalls of the intake manifold, and a notch connected to the intake channel is provided on the other sidewall of the intake manifold.

[0009] Furthermore, the mixer includes a connecting pipe, a ring pipe, and a nozzle. One end of the connecting pipe is connected to the outer wall of the ring pipe, and the other end passes through a notch and is connected to the nozzle, thereby sending the gas ejected from the nozzle into the ring channel of the ring pipe. A plurality of air jets communicating with the ring channel are arranged around the inner wall and / or outer wall of the ring pipe, and a plurality of the nozzles are respectively installed at each air jet.

[0010] Furthermore, the two ends of the central channel of the ring pipe are directly opposite the inlet and outlet of the air intake channel, respectively.

[0011] Preferably, each group of the multi-point injection modules has at least two nozzles.

[0012] Furthermore, the number of gas passages is at least one, and when the number of gas passages is two or more, each gas passage is independent and not connected to the others.

[0013] Furthermore, the number of gas passages is one, and natural gas and hydrogen are simultaneously introduced into the passage as fuel. Each of the nozzles injects a mixture of natural gas and hydrogen.

[0014] Furthermore, there are two gas channels, which are independent of each other and are not connected to each other, and are respectively supplied with natural gas and hydrogen as fuel. Each set of multi-point injection modules uses different nozzles to inject natural gas and hydrogen respectively.

[0015] The natural gas accounts for 92% to 98% of the volume, and the hydrogen accounts for 8% to 2% of the volume.

[0016] The beneficial effects of this invention are:

[0017] 1. This invention employs a multi-point injection module composed of an air guide, an intake manifold, a mixer, and a nozzle. The air guides of several sets of multi-point injection modules are connected in series to form a gas passage. At the same time, each set of multi-point injection modules is set to correspond one-to-one with each cylinder of the gas engine. The gas and air are mixed at the intake manifold of each multi-point injection module to form a mixed gas. The mixed gas is then automatically drawn directly from the air inlet of each cylinder, which can effectively ensure that the mixed gas drawn by each cylinder maintains a uniform and stable air-fuel ratio. This better adapts to the current trend of converting oil to gas and meets the needs of carbon peaking, energy saving, and emission reduction.

[0018] 2. This invention utilizes the nozzles of each group of multi-point injection modules to precisely inject equivalent direct gas at the cylinder inlet, which can effectively shorten the gas supply pipeline and effectively improve the efficiency of gas entering the cylinder and burning to do work, thereby achieving the purpose of instantaneous response injection, mixing and combustion of gas;

[0019] 3. By adding hydrogen to natural gas, this invention can effectively improve the combustion rate of natural gas by taking advantage of the characteristics of hydrogen's fast combustion rate and wide lean-burn limit. On the one hand, it accelerates the work of the cylinder, ensuring that the gas engine has strong and sustainable torque and total power and achieves more powerful performance. On the other hand, it can also achieve better emission standards.

[0020] 4. By simultaneously setting multiple nozzles on each group of multi-point injection modules, the present invention can not only adjust the gas injection speed by controlling the number of nozzles activated, but also allow different nozzles to inject natural gas and hydrogen separately as needed, thereby ensuring that the ratio of natural gas and hydrogen in the mixed gas remains stable.

[0021] The features and advantages of the present invention will be described in detail through embodiments and in conjunction with the accompanying drawings. [Attached Image Description]

[0022] Figure 1 It is the main pipe intake structure of existing gas engines that burn natural gas;

[0023] Figure 2 This is a three-dimensional structural diagram of Example 1;

[0024] Figure 3 This is a three-dimensional structural diagram of the multi-point injection module with a connecting pipe in Embodiment 1;

[0025] Figure 4 This is a three-dimensional structural diagram of the multi-point injection module without a connecting pipe in Embodiment 1;

[0026] Figure 5 This is a three-dimensional structural diagram of the air guide with a connecting pipe in Embodiment 1;

[0027] Figure 6 This is a three-dimensional structural diagram of the intake manifold of Embodiment 1;

[0028] Figure 7 This is a three-dimensional structural diagram of the mixer in Example 1;

[0029] Figure 8 This is a schematic diagram of the gas passage structure in Example 1;

[0030] Figure 9 This is a schematic diagram of the gas passage structure in Example 2.

[0031] In the diagram: 1-Air guide, 11-Support, 111-Installation port, 12-Conduit, 121-Pipe body channel, 13-Connecting pipe, 2-Intake manifold, 21-Intake channel, 22-Notch, 3-Mixer, 31-Connecting pipe, 32-Ring pipe, 33-Air nozzle, 4-Nozzle, 5-Gas passage, 6-Common rail injection, 7-Cylinder, 8-Gas main pipe.

Detailed Implementation Methods

[0032] Example 1:

[0033] See Figures 1 to 8This invention discloses a direct injection mixing intake structure for an LNG gas engine, comprising a multi-point injection module. The multi-point injection module includes a guide vane 1, an intake manifold 2, a mixer 3, and a nozzle 4. The intake manifold 2 is connected to the guide vane 1. The mixer 3 is located within the intake channel 21 of the intake manifold 2. The nozzle 4 is mounted on the guide vane 1 and connected to the mixer 3. Several groups of guide vanes 1 of the multi-point injection modules are sequentially connected and connected in series to form a gas passage 5. The nozzle 4 of each group of multi-point injection modules injects the gas from the gas passage 5 into the mixer 3 of its respective multi-point injection module, where it mixes with the air supplied to the intake manifold 2 of its respective multi-point injection module to form a mixed gas. Each group of multi-point injection modules corresponds one-to-one with each cylinder 7 of the gas engine, and each cylinder 7 automatically draws in the mixed gas generated by its corresponding multi-point injection module.

[0034] The gas guide 1 includes a support base 11 and a conduit 12. The support base 11 is sleeved outside the conduit 12 and has two mounting ports 111 for fixing the nozzle 4. The two mounting ports 111 are respectively connected to the pipe channel 121 of the conduit 12. The conduits 12 of the gas guide 1 of each multi-point injection module are connected in sequence and the pipe channels 121 are connected in series to form a gas passage 5.

[0035] The free end of the conduit 12 located at one end of the gas passage 5 is sealed by a sealing plate, and the free end of the conduit 12 located at the other end of the gas passage 5 is also equipped with a connecting pipe 13.

[0036] An intake channel 21 is formed between the two opposite side walls of the intake manifold 2, and a notch 22 connected to the intake channel 21 is provided on the other side wall of the intake manifold 2.

[0037] The mixer 3 includes a connecting pipe 31, an annular pipe 32, and a nozzle 33. One end of the connecting pipe 31 is connected to the outer wall of the annular pipe 32, and the other end passes through the notch 22 and is connected to the nozzle 4, thereby sending the gas ejected from the nozzle 4 into the annular channel of the annular pipe 32. A plurality of air jets connected to the annular channel are arranged around the inner wall and / or outer wall of the annular pipe 32. A plurality of nozzles 33 are respectively installed at each air jet.

[0038] The two ends of the central channel of the ring pipe 32 are respectively aligned with the inlet and outlet of the air intake channel 21.

[0039] Each set of the multi-point injection modules has two nozzles 4.

[0040] The number of gas passages 5 is one, and natural gas and hydrogen are simultaneously introduced into the passage as fuel. Each of the nozzles 4 injects a mixture of natural gas and hydrogen.

[0041] The working process of this invention:

[0042] During operation, natural gas and hydrogen flow along... Figure 8 The gas is fed into the same gas passage 5 from directions C and D, forming a mixture of natural gas and hydrogen. Natural gas accounts for 95% of the volume, while hydrogen accounts for 5%. Subsequently, the nozzles 4 of each multi-point injection module inject the mixture of natural gas and hydrogen along the connecting pipe 31 into the annular channel of the ring pipe 32, and then through each nozzle 33 into the intake channel of the intake manifold 2. Simultaneously, air is fed into the intake channels of the intake manifold 2 of each multi-point injection module, mixing with the mixture of natural gas and hydrogen to form a gas mixture. Finally, each cylinder 7 draws in the gas mixture produced by its corresponding multi-point injection module.

[0043] The injection speed of the mixed gas in each group of multi-point injection modules can be controlled by the number of nozzles 4 activated in each group of multi-point injection modules. For example, when both nozzles 4 of each group of multi-point injection modules are activated simultaneously, high-speed injection of the mixed gas is achieved, while when only one of the two nozzles 4 of each group of multi-point injection modules is activated, low-speed injection of the mixed gas is achieved.

[0044] In addition, hydrogen can be produced by pyrolysis during vehicle operation.

[0045] Example 2:

[0046] See Figure 9 The number of gas channels 5 is two. The two gas channels 5 are independent of each other and are not connected to each other. They are respectively supplied with natural gas and hydrogen as fuel. Each group of multi-point injection modules uses different nozzles 4 to inject natural gas and hydrogen respectively.

[0047] Everything else is the same as in Example 1.

[0048] The working process of this invention:

[0049] During operation, natural gas and hydrogen flow along... Figure 9 The gas is fed into two gas passages 5 in directions E and F. Natural gas comprises 95% by volume, while hydrogen comprises 5%. Subsequently, each multi-point injection module uses different nozzles 4 to inject natural gas and hydrogen along the connecting pipe 31 into the annular channel of the ring pipe 32, and then through each nozzle 33 into the intake passage of the intake manifold 2. Simultaneously, air is fed into the intake passage of each multi-point injection module's intake manifold 2, thus mixing the natural gas, hydrogen, and air to form a gas mixture. Finally, each cylinder 7 draws in the gas mixture produced by its corresponding multi-point injection module.

[0050] The above embodiments are illustrative of the present invention and are not intended to limit the present invention. Any simple modifications to the present invention are within the scope of protection of the present invention.

Claims

1. A direct injection mixing-type air intake structure for an LNG gas engine, characterized in that: The system includes a multi-point injection module, which includes an air guide (1), an intake manifold (2), a mixer (3), and a nozzle (4). The intake manifold (2) is connected to the air guide (1). The mixer (3) is located in the intake passage (21) of the intake manifold (2). The nozzle (4) is installed on the air guide (1) and connected to the mixer (3). Several sets of air guides (1) of the multi-point injection module are connected in sequence and series to form a gas passage (5). The nozzle (4) of each set of the multi-point injection module injects the gas in the gas passage (5) into the mixer (3) of the multi-point injection module and mixes it with the air sent into the intake manifold (2) of the multi-point injection module to form a mixed gas. Each set of the multi-point injection module is set one-to-one with each cylinder (7) of the gas engine. Each cylinder (7) automatically draws in the mixed gas generated by the corresponding multi-point injection module. The air guide (1) includes a support base (11) and a conduit (12). The support base (11) is sleeved outside the conduit (12) and has a number of mounting ports (111) for fixing the nozzle (4). Each mounting port (111) is connected to the pipe channel (121) of the conduit (12). The conduits (12) of the air guide (1) of each multi-point injection module are connected in sequence and the pipe channels (121) are connected in series to form a gas passage (5). The number of nozzles (4) in each group of the multi-point injection modules is at least two; The number of gas passages (5) is at least one, and when the number of gas passages (5) is two or more, each gas passage (5) is independent and not connected to each other.

2. The direct injection mixing intake structure for an LNG gas engine as described in claim 1, characterized in that: The free end of the conduit (12) located at one end of the gas passage (5) is sealed by a sealing plate, and the free end of the conduit (12) located at the other end of the gas passage (5) is also equipped with a connecting pipe (13).

3. The direct injection mixing intake structure for an LNG gas engine as described in claim 1, characterized in that: An intake channel (21) is formed between the two opposite side walls of the intake manifold (2), and a notch (22) connected to the intake channel (21) is provided on the other side wall of the intake manifold (2).

4. The direct injection mixing air intake structure for an LNG gas engine as described in claim 3, characterized in that: The mixer (3) includes a connecting pipe (31), a ring pipe (32) and a nozzle (33). One end of the connecting pipe (31) is connected to the outer wall of the ring of the ring pipe (32), and the other end passes through the notch (22) and is connected to the nozzle (4) to send the gas ejected from the nozzle (4) into the ring channel of the ring pipe (32). The inner wall and / or outer wall of the ring of the ring pipe (32) are provided with a number of air jets that communicate with the ring channel. The nozzles (33) are installed at each air jet.

5. The direct injection mixing intake structure for an LNG gas engine as described in claim 4, characterized in that: The two ends of the central channel of the ring pipe (32) are respectively opposite to the inlet and outlet of the air intake channel (21).

6. The direct injection mixing intake structure for an LNG gas engine as described in claim 1, characterized in that: The number of gas passages (5) is one, and natural gas and hydrogen are simultaneously introduced into the passage as gas. Each of the nozzles (4) injects a mixture of natural gas and hydrogen.

7. The direct injection mixing intake structure for an LNG gas engine as described in claim 1, characterized in that: The number of gas channels (5) is two. The two gas channels (5) are independent of each other and are not connected to each other. Natural gas and hydrogen are respectively introduced as gas. Each group of multi-point injection modules uses different nozzles (4) to inject natural gas and hydrogen respectively.

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