Intake dual-flow channel cylinder head and method

Abstract

The present invention provides an intake dual-flow channel cylinder head and method, which relate to the field of engine cylinder heads, including a cylinder head substrate, wherein independent gas flow channels, air flow channels and exhaust flow channels are arranged in the cylinder head substrate, wherein the gas flow channel is located on one side of the cylinder body axis matched with the cylinder head substrate, and the air flow channel is located on the other side of the cylinder body axis matched with the cylinder head substrate, and a cooling water cavity isolated from the gas flow channel and the air flow channel is arranged between the gas flow channel and the air flow channel. Aiming at the problems of "backfire", "blasting" and poor mixing effect in the cylinder caused by unreasonable cylinder head structure of current hydrogen-rich and hydrogen engines, opposed dual flow channels are used to completely separate the gas and air channels to ensure mixing of the gas and air in the cylinder, thereby solving the problems of "backfire" in the premixing method and gas leakage in non-completely independent flow channels, and the opposed dual flow channels improve the mixing effect in the cylinder and improve the thermal efficiency of the engine.

Description

Technical Field

[0001] The present invention relates to the field of engine cylinder heads, and in particular to an intake dual-flow channel cylinder head and a method thereof. Background Art

[0002] The combustion in the cylinder of a gas engine usually uses a spark plug to ignite the mixture of gas and air in the cylinder. In existing natural gas and biogas engines (such as Jichai G190 series, H190 series; Caterpillar G34 series, G35 series, G36 series; Jenbacher 3 / 4 / 6 series), the gas and air are mixed mostly by premixing and multi-point mixing in the intake manifold / intake duct. Premixing technology means that the gas and air are mixed before the compressor or before the intake pipe, and the passage before the intake pipe is a mixture of gas and air; multi-point mixing technology in the intake duct means that the gas and air are mixed in the intake manifold or intake duct, and the air duct is a mixture of gas and air.

[0003] Compared with natural gas and other fuel gases, hydrogen burns faster and has a wider explosion limit, making it more prone to "backfire" and "explosion" problems. In hydrogen-rich engines and hydrogen engines, premixing and intake manifold / intake duct multi-point mixing methods cannot solve safety problems such as "backfire", and the stronger the engine power, the greater the risk of "backfire". Some hydrogen engines under development use direct injection of gas into the cylinder, which has high requirements for gas pressure. Industrial exhaust and other hydrogen-containing sources are difficult to meet this requirement, and are difficult to use in high-power hydrogen-rich engines or hydrogen engines. Some hydrogen-rich engines use opening control valves such as butterfly valves. During the engine working cycle, the gas continuously fills the gas intake system in front of the valve. There is still a risk of "backfire" during the valve overlap period, load and speed fluctuations, and when the valve is not tightly sealed.

[0004] In the prior art, there is a scheme for separately conveying gas and air into the cylinder for mixing in the cylinder, but the flow passages for conveying gas and air are formed by dividing the same intake passage, and the air and gas flow passages are connected to the cylinder in parallel. However, as the engine runs, its separation structure is prone to failure and leakage, resulting in the connection between the gas and air flow passages to form a premixing effect, inducing "backfire" and "backfire" problems. After the air and gas are input into the cylinder through the parallel air and gas flow passages, due to the influence of their flow passage structure, the mixing effect of air and gas in the cylinder is poor, affecting the thermal efficiency of the gas. Summary of the invention

[0005] The purpose of the present invention is to address the defects of the prior art and provide an intake dual-flow channel cylinder head and method, which uses opposed dual flow channels to completely separate the gas and air channels to ensure that the gas and air are mixed in the cylinder, solving the problems of "backfire" in the premixing method and gas leakage in non-completely independent flow channels. The opposed dual flow channels improve the mixing effect in the cylinder and improve the thermal efficiency of the engine.

[0006] The first object of the present invention is to provide an intake dual-flow channel cylinder head, which adopts the following scheme:

[0007] It includes a cylinder head base, in which are provided independent gas flow channels, air flow channels and exhaust flow channels. The gas flow channel is located on one side of the cylinder body axis matched with the cylinder head base, and the air flow channel is located on the other side of the cylinder body axis matched with the cylinder head base. A cooling water cavity is provided between the gas flow channel and the air flow channel to isolate the two.

[0008] Furthermore, the gas flow channel and the air flow channel are designed to be opposed to each other, and the inlet of the gas flow channel and the inlet of the air flow channel are located on different sides of the cylinder head base.

[0009] Furthermore, a first curved section is provided in the air flow channel, and a first air inlet valve is provided at the throat of the air flow channel. The first curved section guides part of the air flow in the air flow channel to be output from the throat position along a tangential direction parallel to the first curved section.

[0010] Furthermore, a second curved section is provided in the gas flow passage, and a second air inlet valve is provided at the throat of the gas flow passage. The second curved section guides part of the gas flow in the gas flow passage to be output from the throat position along a tangential direction parallel to the second curved section.

[0011] Furthermore, the positions of the air flow channel and the gas flow channel are symmetrically distributed relative to the axis of the matching cylinder body, and part of the guided gas flow and part of the air flow collide in the cylinder body to form a vortex, thereby performing mixing in the cylinder.

[0012] Furthermore, the inlet of the gas flow channel is equipped with a gas injection valve, and the gas injection valve is used to control the timing and duration of gas supply.

[0013] Furthermore, the gas flow channel is connected to the gas inlet pipe through a gas pipe, and the gas injection valve is installed on the gas pipe.

[0014] A second object of the present invention is to provide a working method of the intake dual-flow channel cylinder head as described in the first object, comprising:

[0015] Connect the gas flow channel inlet to the gas source, and connect the air flow channel inlet on the opposite side of the gas flow channel inlet to the air source;

[0016] After the gas is guided through the gas flow channel, part of the gas is tilted and input into the cylinder body relative to the axis of the gas flow channel throat; after the air is guided through the air flow channel, part of the air is tilted and input into the cylinder body relative to the axis of the air flow channel throat, and collides with part of the gas tilted and input into the cylinder body to form a vortex, thereby mixing in the cylinder.

[0017] Furthermore, the supply timing and duration of the gas in the gas flow passage are controlled, the gas supply timing is controlled after the engine exhaust valve is closed, and the gas supply stop timing is controlled before the intake valve of the gas flow passage is closed.

[0018] Furthermore, the gas intake process avoids the compression stroke, and the gas and air enter the engine cylinder through corresponding flow passages during the intake stroke and are mixed in the cylinder.

[0019] Compared with the prior art, the present invention has the following advantages and positive effects:

[0020] (1) In order to solve the problems of "backfire" and "backfire" and poor mixing effect in the cylinder caused by unreasonable cylinder head structure in current hydrogen-rich and hydrogen engines, opposed double flow passages are used to completely separate the gas and air passages to ensure that the gas and air are mixed in the cylinder, solving the problems of "backfire" in the premixing method and gas leakage in non-completely independent flow passages. The opposed double flow passages improve the mixing effect in the cylinder and improve the thermal efficiency of the engine.

[0021] (2) The first inlet of the air flow channel and the second inlet of the gas channel are located on opposite surfaces of the cylinder head substrate and remain separated, ensuring that the gas and air are not mixed in the cylinder head substrate before entering the cylinder body, and there is no combustible mixture in the intake system and the air channel.

[0022] (3) A cooling water chamber is also provided in the area between the air flow channel and the gas flow channel to protect the area between the air flow channel and the gas flow channel that is prone to damage and leakage, reduce the adverse effect of high heat of the cylinder block on the internal structure of the cylinder head base, and completely separate the air flow channel and the gas flow channel.

[0023] (4) The gas intake is controlled by the injection valve, and the gas supply is controllable at all times, avoiding the combustible gas scavenging and backflow existing in intake control methods such as butterfly valves, further ensuring the safety of the intake system. Compared with the premixing method, it reduces the gas scavenging consumption and improves the thermal efficiency by more than 3%. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0025] Figure 1 Schematic diagram of the distribution of the flow channels of the intake dual-flow channel cylinder head in Examples 1 and 2 of the present invention.

[0026] Figure 2 Schematic diagram of the air flow channels of the intake dual-flow channel cylinder head in embodiments 1 and 2 of the present invention.

[0027] Figure 3Schematic diagram of the gas flow passages of the intake dual-flow passage cylinder head in embodiments 1 and 2 of the present invention.

[0028] Figure 4 Schematic diagram of the positions of the air flow channel, the gas flow channel and the cooling water cavity in Examples 1 and 2 of the present invention.

[0029] Figure 5 It is a cross-sectional schematic diagram of the air flow channel and the gas flow channel in Examples 1 and 2 of the present invention.

[0030] Figure 6 Schematic diagram of the arrangement position of the gas injection valve in Examples 1 and 2 of the present invention.

[0031] Among them, 1. exhaust flow channel, 2. air flow channel, 3. cylinder head base, 4. gas flow channel, 5. gas injection valve, 6. gas source, 7. cooling water chamber, 8. gas intake pipe, 9. second intake valve, 10. first intake valve. DETAILED DESCRIPTION

[0032] Example 1

[0033] In a typical embodiment of the present invention, Figure 1-Figure 6 As shown, an intake dual-flow channel cylinder head is provided.

[0034] When the existing premixing and intake manifold / intake port multi-point injection technology is applied to hydrogen-rich and hydrogen engines, there are problems of "backfire" and "backfire", which limit the power output of the engine when using hydrogen-rich and hydrogen fuels. During the operation of the engine, the entire gas channel is filled with gas, and "backfire" is prone to occur during the valve opening overlap angle, load fluctuations, or when the valve is not tightly sealed due to various reasons, leading to safety problems. Due to the structural form of the gas and air flow channels, the failure of the flow channel separation structure causes the gas and air flow channels to be connected, resulting in a premixing effect and inducing "backfire" and "backfire" problems. There is also the problem of poor mixing effect in the cylinder.

[0035] Based on this, the present embodiment provides an intake dual-flow channel cylinder head, which uses opposing dual flow channels to completely separate the gas flow channel 4 and the air flow channel 2, ensuring that the gas and air are mixed in the cylinder, solving the problems of "backfire" in the premixing method and gas leakage in non-completely independent flow channels. The opposed dual flow channels improve the mixing effect in the cylinder and improve the thermal efficiency of the engine.

[0036] The above-mentioned intake dual-flow channel cylinder head will be described in detail below with reference to the accompanying drawings.

[0037] See also Figure 1The intake dual-flow channel cylinder head includes a cylinder head base 3, on which are provided independent gas flow channels 4, air flow channels 2 and exhaust flow channels 1, the gas flow channels 4 being located on one side of the axis of the cylinder body matched with the cylinder head base 3, and the air flow channels 2 being located on the other side of the axis of the cylinder body matched with the cylinder head base 3, and a cooling water cavity 7 is provided between the gas flow channels 4 and the air flow channels 2 to be isolated from the two; after the cylinder head base 3 is matched with the cylinder body, the gas flow channels 4, the air flow channels 2 and the exhaust flow channels 1 are respectively communicated with the inside of the cylinder body.

[0038] The gas flow channel 4 and the air flow channel 2 are designed to be opposed to each other, so that the cylinder head space can be fully utilized. Compared with the traditional method of obtaining two flow channels arranged on the same side by dividing the gas flow channel, the gas flow channel 4 and the air flow channel 2 in this embodiment have a larger arrangement space, and the size of the gas flow channel 4 on the cylinder head base 3 can be enlarged, so that the inlet area of ​​the gas flow channel 4 is increased by more than 30% compared with the traditional same-side arrangement.

[0039] As for the supply of gas and air, after the inlet area of ​​the gas flow channel 4 is increased, the gas intake volume is improved under the same intake pressure, which compensates for the adverse effects of gaseous hydrogen enrichment and low calorific value of hydrogen on the engine output power. At the same time, combined with the opposing distribution of the gas flow channel 4 and the air flow channel 2, the gas and air flow in opposite directions during the intake process, thereby enhancing the mixing in the cylinder.

[0040] Figure 2 The figure shows a schematic diagram of the structure of the air flow channel 2, wherein one end of the air flow channel 2 is a first inlet, and the other end is a first throat. The first throat is equipped with a first intake valve 10, and the first intake valve 10 is an air intake valve. Between the first inlet and the first throat, the air flow channel 2 is provided with a first curved section, and the air entering the air flow channel 2 is guided through the first curved section so that part of the air is close to the distal side of the corresponding arc of the first curved section. When the guided air passes through the first throat position and enters the cylinder, part of the air is caused to be output along a tangential direction parallel to the first curved section, and part of the air is output along an inclined direction relative to the axis of the first intake valve 10.

[0041] Figure 3 The figure shows a schematic diagram of the structure of the gas flow channel 4. One end of the gas flow channel 4 is a second inlet, and the other end is a second throat. The second throat is equipped with a second intake valve 9, and the second intake valve 9 is a gas intake valve. Between the second inlet and the second throat, the gas flow channel 4 is provided with a second curved section. The gas entering the gas flow channel 4 is guided by the second curved section, so that part of the gas is close to the distal side of the corresponding arc of the second curved section. When the guided gas passes through the second throat position and enters the cylinder, part of the gas is output along the tangential direction parallel to the second curved section, and part of the gas is output along the inclined direction relative to the axis of the second intake valve 9.

[0042] Figure 5It is a cross-sectional schematic diagram of the air flow channel 2 and the gas flow channel 4. The gas flow channel 4 and the intake flow channel are located on both sides of the cylinder axis, and their distribution positions are symmetrical relative to the cylinder axis. The corresponding first curved section and second curved section have opposite bending directions. After part of the air flow is output obliquely through the first throat, it gradually moves toward the axis of the second intake valve 9; after part of the gas flow is output obliquely through the second throat, it gradually moves toward the axis of the first intake valve 10; after part of the air flow and part of the gas flow flow flow in opposite directions, airflow collision occurs in the cylinder body of the cylinder to form a vortex, thereby strengthening the mixing of gas and air in the cylinder body.

[0043] Traditionally, the gas flow channel is divided to obtain two flow channels arranged on the same side. The curvatures of the two flow channels tend to be consistent. Part of the airflow guided by the curved section still maintains parallel flow after being output through the throat position. Effective collision and mixing cannot be formed between the gas and the air, resulting in low mixing efficiency.

[0044] The gas and air are completely isolated before entering the cylinder to achieve in-cylinder mixing. The collision of gas and air forms a vortex to improve the mixing effect. Compared with traditional direct injection, it can reduce the gas intake pressure from 1.5-30MPa to below 1MPa, reducing the pressure requirement for the gas source.

[0045] like Figure 1 , Figure 4 As shown, the air flow channel 2 and the gas flow channel 4 in the cylinder head base 3 are independent of each other. At the same time, a cooling water chamber 7 is also provided in the area between the air flow channel 2 and the gas flow channel 4 to protect the area between the air flow channel 2 and the gas flow channel 4 that is prone to damage and leakage, thereby reducing the adverse effect of high temperature of the cylinder body on the internal structure of the cylinder head base 3, and completely separating the air flow channel 2 and the gas flow channel 4. The first inlet of the air flow channel 2 and the second inlet of the gas channel are on opposite surfaces of the cylinder head base 3 and remain separated, ensuring that the gas and air are not mixed in the cylinder head base 3 before entering the cylinder body, and there is no combustible mixture in the intake system and the air channel.

[0046] In order to further ensure stable power output when using hydrogen-rich and hydrogen fuels, a gas injection valve 5 is added to the flow path of the gas in this embodiment. The gas injection valve 5 is located at the first inlet position of the gas flow channel 4, such as Figure 6 As shown, the on / off and opening size of the connection between the gas inlet pipe 8 and the gas flow channel 4 are controlled, thereby controlling the gas supply timing and duration.

[0047] Traditionally, the gas intake volume is controlled by a butterfly valve, and the gas channel and the cylinder are separated only by the intake valve. During the operation of the engine, the entire gas flow channel 4 is filled with gas. During the overlapping angle of the valve opening, when the gas enters the exhaust system and the piston moves upward, the mixed gas flows back into the gas system, or when the engine speed / load fluctuates, there is a risk of backfire, leading to safety problems. This embodiment is aimed at the "backfire" problem of the butterfly valve control intake volume technology in the application of hydrogen-rich and hydrogen engines, and configures the gas flow channel 4 to circulate and inject gas at a fixed time to eliminate the "backfire" risk of the butterfly valve control intake volume method.

[0048] Specific, combined Figure 1 , Figure 5 and Figure 6 A gas injection valve 5 is provided at the inlet of the gas flow channel 4 to control the timing and duration of gas supply. The opening timing of the gas injection valve 5 is controlled after the exhaust valve of the engine is closed, thereby avoiding the valve overlap scavenging process.

[0049] At the same time, the gas cycle intake volume is calculated according to the power, engine thermal efficiency, speed and gas calorific value, and then the injection valve opening duration is determined according to the gas intake pressure difference and the flow coefficient of the gas injection valve 5. The gas intake pressure difference is controlled between 0.1MPa and 0.15MPa, and the duration is controlled between 90° and 120° crankshaft angles, so that the injection valve closing time is controlled before the first intake valve 10 is closed, thereby blocking the backflow of the mixture in the cylinder to the gas system.

[0050] In order to reduce the gas pressure requirement, the gas intake process avoids the compression stroke. The gas and air enter the engine cylinder through corresponding flow channels during the intake stroke and are mixed in the cylinder. The maximum gas injection pressure is less than 0.5MPa.

[0051] The gas intake is controlled by the injection valve, and the gas supply is controllable at all times, avoiding the combustible gas scavenging and backflow existing in intake control methods such as butterfly valves, further ensuring the safety of the intake system. Compared with the premixing method, it reduces the gas scavenging consumption and improves the thermal efficiency by more than 3%.

[0052] Compared with the premixing mode, the control system adjusts the duration of the gas injection valve 5 and the gas pressure when the load changes, which is independent of the supercharger response speed. Therefore, the transient response characteristics of the engine are better than the premixing intake mode.

[0053] Combination Figure 2 , Figure 3 In order to ensure the position accuracy of the intake and exhaust runners 1 relative to the cylinder head base 3, three-dimensional software is used to design the opposing intake and exhaust runners 1, and 3D printing technology is used to generate double runners and cooling water chamber 7 sand cores for blank casting; a machining center is used to complete the cylinder head processing, and finally the assembly of the cylinder head base 3 components and the installation of the gas injection valve 5 are completed.

[0054] Specifically, the intake dual-flow cylinder head in this embodiment is designed on 190 mm cylinder diameter and 200 mm cylinder diameter engines for use in hydrogen-rich gas engines. The following is an example of an intake dual-flow cylinder head for a 200 mm cylinder diameter hydrogen-rich engine.

[0055] Air duct design: According to the cylinder diameter, door position, and valve mechanism layout, the exhaust flow channel 1, air flow channel 2, and gas flow channel 4 are designed separately using 3D design software. The air flow channel 2 and gas flow channel 4 are designed independently and separately from each other. The design of the air flow channel 2 and the gas flow channel 4 takes the flow coefficient as the optimization target.

[0056] Cylinder head design: design the cooling water cavity 7, and design the cylinder head base 3 structure in three-dimensional design software according to the air channel and the cooling water cavity 7. The cylinder head includes an exhaust flow channel 1, an air flow channel 2, and a gas flow channel 4 which are separated from each other.

[0057] Cylinder head manufacturing: Based on the three-dimensional design model of the flow channel and the cylinder head base 3, 3D printing technology is used to generate double flow channels and cooling water chamber 7 sand cores, and blank casting is performed; the cylinder head is processed and assembled using a machining center.

[0058] Selection of gas injection valve 5: Select gas injection valve 5 according to gas flow and injection pressure requirements. The injection valve has a diameter of 47 mm and is installed before the cylinder head gas intake passage to control the duration and gas pressure of the gas in the passage between the gas intake pipe 8 and the gas flow passage 4.

[0059] Example 2

[0060] In another typical embodiment of the present invention, Figure 1-Figure 6 As shown, a working method of an intake dual-flow channel cylinder head is given.

[0061] The following steps are involved:

[0062] Connect the inlet of the gas flow channel 4 to the gas source 6, and connect the inlet of the air flow channel 2 on the opposite side of the inlet of the gas flow channel 4 to the air source;

[0063] After the gas is guided through the gas flow channel 4, part of the gas is tilted and input into the cylinder relative to the axis of the throat of the gas flow channel 4; after the air is guided through the air flow channel 2, part of the air is tilted and input into the cylinder relative to the axis of the throat of the air flow channel 2, and collides with part of the gas tilted and input into the cylinder to form a vortex, thereby performing mixing in the cylinder.

[0064] In order to improve the stable power output when using hydrogen-rich and hydrogen fuels, the supply timing and duration of the gas in the gas flow channel 4 are controlled. The gas supply timing is controlled after the engine exhaust valve is closed, and the gas supply stop timing is controlled before the intake valve of the gas flow channel 4 is closed.

[0065] In order to reduce the gas pressure requirement, the gas intake process avoids the compression stroke. The gas and air enter the engine cylinder through corresponding flow channels during the intake stroke and are mixed in the cylinder. The maximum gas injection pressure is less than 0.5MPa.

[0066] The gas intake is controlled by the injection valve, and the gas supply is controllable at all times, avoiding the combustible gas scavenging and backflow existing in intake control methods such as butterfly valves, further ensuring the safety of the intake system. Compared with the premixing method, it reduces the gas scavenging consumption and improves the thermal efficiency by more than 3%.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An intake dual-flow channel cylinder head, characterized in that: It comprises a cylinder head base body, in which mutually independent gas flow passages, air flow passages and exhaust flow passages are arranged, the gas flow passage is located on one side of the cylinder body axis matched with the cylinder head base body, the air flow passage is located on the other side of the cylinder body axis matched with the cylinder head base body, and a cooling water cavity is arranged between the gas flow passage and the air flow passage to be isolated from the two; the gas flow passage and the air flow passage are designed to be opposite to each other; The air flow channel is provided with a first curved section, and the throat of the air flow channel is equipped with a first air inlet valve; the first curved section guides part of the air flow in the air flow channel to be output from the throat position along a tangential direction parallel to the first curved section; A second curved section is provided in the gas flow passage, and the second curved section guides a part of the gas flow in the gas flow passage to be output from the throat position along a tangential direction parallel to the second curved section.

2. The intake dual-flow cylinder head according to claim 1, characterized in that: The inlet of the fuel gas flow passage and the inlet of the air flow passage are located on different sides of the cylinder head base.

3. The intake dual-flow cylinder head according to claim 1, characterized in that: The throat of the fuel gas flow passage is matched with a second intake valve.

4. The intake dual-flow cylinder head according to claim 1, characterized in that: The positions of the air flow channel and the gas flow channel are symmetrically distributed relative to the axis of the matched cylinder body. The guided part of the gas flow and part of the air flow collide in the cylinder body to form a vortex, and are mixed in the cylinder.

5. The intake dual-flow cylinder head according to claim 1, characterized in that: The inlet of the gas flow channel is equipped with a gas injection valve, which is used to control the timing and duration of gas supply.

6. The intake dual-flow channel cylinder head according to claim 5, characterized in that: The gas flow channel is connected to the gas inlet pipe through the gas pipe, and the gas injection valve is installed on the gas pipe.

7. A method for operating an intake dual-flow cylinder head as claimed in any one of claims 1 to 6, characterized in that: include: Connect the gas flow channel inlet to the gas source, and connect the air flow channel inlet on the opposite side of the gas flow channel inlet to the air source; After the gas is guided through the gas flow channel, part of the gas is tilted and input into the cylinder body relative to the axis of the gas flow channel throat; after the air is guided through the air flow channel, part of the air is tilted and input into the cylinder body relative to the axis of the air flow channel throat, and collides with part of the gas tilted and input into the cylinder body to form a vortex, thereby mixing in the cylinder.

8. The operating method of the intake dual-flow channel cylinder head according to claim 7, characterized in that: The supply timing and duration of the gas in the gas flow passage are controlled, the gas supply timing is controlled after the engine exhaust valve is closed, and the gas supply stop timing is controlled before the intake valve of the gas flow passage is closed.

9. The operating method of the intake dual-flow channel cylinder head according to claim 8, characterized in that: The gas intake process avoids the compression stroke, and the gas and air enter the engine cylinder through corresponding flow channels during the intake stroke and mix in the cylinder.

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