Engine control method and engine

Abstract

The invention belongs to the technical field of engines, and discloses an engine control method and an engine. The engine control method comprises the steps that according to preset injection pressure and preset injection amount, the corresponding limit starting scavenging crankshaft angle range when scavenging is started for a pre-combustion chamber is determined; according to the temperature of the main combustion chamber, the pressure of the main combustion chamber, the preset injection pressure and the limit starting scavenging crank angle range, it is determined that the precombustion chamber starting scavenging condition is met; and starting to scavenge the pre-combustion chamber at the preset injection pressure and the preset injection amount. By the adoption of the engine control method, the scavenging quality and efficiency of scavenging of the pre-combustion chamber can be effectively improved, and the ignition efficiency and reliability of ignition of fuel gas in the pre-combustion chamber can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and in particular to an engine control method and an engine. Background Art

[0002] Pre-combustion chamber ignition is one of the main ways to achieve engine ignition. It uses a spark plug in the pre-combustion chamber to ignite the pilot gas, and sprays the ignited high-temperature and high-pressure pilot gas into the main combustion chamber through the channel between the pre-combustion chamber and the main combustion chamber to ignite the gas in the main combustion chamber. This can significantly shorten the combustion duration of the gas in the main combustion chamber, ignite lean gas, reduce combustion temperature, reduce NOx emissions, improve combustion efficiency, and reduce engine gas consumption, etc., so it is widely studied and applied. Specifically, pre-combustion chamber ignition includes active ignition and passive ignition. Active ignition refers to the gas in the pre-combustion chamber being fed from the outside of the engine by an independent pipeline and ignited by a spark plug; passive ignition refers to the gas in the pre-combustion chamber being pressed into the main combustion chamber by a piston and ignited by a spark plug.

[0003] For active ignition, the existing technology usually arranges to scavenge the pre-combustion chamber at the end of the exhaust stage of the main combustion chamber and the intake stage of the main combustion chamber, and injects fuel gas into the pre-combustion chamber during the compression stage of the main combustion chamber. Although it is possible to ignite the fuel gas in the main combustion chamber, the scavenging quality and scavenging efficiency of the pre-combustion chamber, and the ignition efficiency and ignition reliability of igniting the fuel gas in the pre-combustion chamber all need to be improved. Summary of the invention

[0004] The object of the present invention is to provide an engine control method and an engine to solve the above-mentioned problems existing in the active ignition in the prior art.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] An engine control method, comprising:

[0007] Determining a limit scavenging crank angle range corresponding to when scavenging of the pre-combustion chamber starts according to a preset injection pressure and a preset injection amount;

[0008] Determining that the pre-combustion chamber scavenging start condition is met according to the temperature of the main combustion chamber, the pressure of the main combustion chamber, the preset injection pressure and the limit scavenging start crank angle range;

[0009] The pre-combustion chamber starts to be scavenged at the preset injection pressure and the preset injection amount.

[0010] As a preferred embodiment of the above engine control method, the step of determining the limit scavenging crank angle range corresponding to the start of scavenging of the pre-combustion chamber according to the preset injection pressure and the preset injection amount includes:

[0011] The limit start scavenging crank angle range is retrieved from a table according to the preset injection pressure and the preset injection amount; wherein the table is formed by the preset injection pressure, the preset injection amount and the limit start scavenging crank angle range.

[0012] As a preferred embodiment of the above-mentioned engine control method, the step of determining the condition for starting scavenging in the pre-combustion chamber according to the temperature of the main combustion chamber, the pressure of the main combustion chamber, the preset injection pressure and the limit scavenging crank angle range comprises:

[0013] Determine whether the crankshaft angle is within the limit start scavenging crankshaft angle range; determine whether the temperature of the main combustion chamber is less than or equal to the set temperature; determine whether the pressure difference is greater than or equal to the set scavenging pressure difference; the pressure difference = preset injection pressure - pressure of the main combustion chamber;

[0014] If the crankshaft angle is within the limit scavenging crankshaft angle range, the temperature of the main combustion chamber is less than or equal to the set temperature, and the pressure difference is greater than or equal to the set scavenging pressure difference, it is determined that the pre-combustion chamber scavenging start condition is met.

[0015] As a preferred solution of the above engine control method, the value range of the set temperature is: 600K~800K;

[0016] The value range of the set scavenging air pressure difference is: 4bar~7bar.

[0017] As a preferred solution of the above engine control method, the preset injection pressure has a value range of: 7 bar to 10 bar;

[0018] The value range of the preset injection amount is: (0.5%*total gas amount) to (1%*total gas amount);

[0019] The total fuel gas volume is the total amount of fuel gas injected into the pre-combustion chamber and the main combustion chamber in each working cycle of the engine; the volume of the pre-combustion chamber accounts for 1% to 1.5% of the volume of the main combustion chamber.

[0020] As a preferred solution of the above engine control method, the preset injection pressure is 8 bar, the preset injection amount is (1%*total fuel gas amount), and the limit start scavenging crankshaft angle range is: -345°CA to -180°CA.

[0021] As a preferred solution of the above engine control method, after starting to scavenge the pre-combustion chamber with the preset injection pressure and the preset injection amount, the method further includes the following steps:

[0022] Determine whether the pressure difference is less than the set intake-combustion pressure difference; the pressure difference = preset injection pressure - the pressure of the main combustion chamber; if the pressure difference is less than the set intake-combustion pressure difference, start injecting fuel into the pre-combustion chamber at the preset injection pressure and the preset injection amount.

[0023] As a preferred solution of the above engine control method, the value range of the set intake-fuel pressure difference is: (1 bar, 4 bar).

[0024] An engine, the engine comprising a pre-combustion chamber structure, the pre-combustion chamber structure comprising a pre-combustion chamber body, the pre-combustion chamber body being provided with a pre-combustion chamber and an intake passage communicating with the pre-combustion chamber, for implementing the above-mentioned engine control method.

[0025] As a preferred embodiment of the above engine, the pre-combustion chamber comprises a spherical first sub-chamber, a conical second sub-chamber and a cylindrical third sub-chamber; along the height direction of the pre-combustion chamber, the first sub-chamber is connected with the large end of the second sub-chamber and is located above the second sub-chamber, and the third sub-chamber is connected with the small end of the second sub-chamber and is located below the second sub-chamber;

[0026] The air intake passage comprises a sub-air intake passage connected to the first sub-chamber; the sub-air intake passage is arc-shaped; along the height direction of the pre-combustion chamber, the opening of the sub-air intake passage faces downward, and the sub-air intake passage is located at the top of the first sub-chamber.

[0027] Beneficial effects of the present invention:

[0028] The present invention provides an engine control method and an engine. The engine control method includes: determining the corresponding limit scavenging crank angle range when starting to scavenging the pre-combustion chamber according to the preset injection pressure and the preset injection amount; determining the conditions for starting to scavenging the pre-combustion chamber according to the temperature of the main combustion chamber, the pressure of the main combustion chamber, the preset injection pressure and the limit scavenging crank angle range; and starting to scavenging the pre-combustion chamber with the preset injection pressure and the preset injection amount. By adopting the engine control method, the scavenging quality and scavenging efficiency of scavenging the pre-combustion chamber can be effectively improved, and the ignition efficiency and ignition reliability of igniting the gas in the pre-combustion chamber can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a cross-sectional view of a pre-combustion chamber structure provided by a specific embodiment of the present invention along a first viewing angle;

[0030] Figure 2 is a cross-sectional view of a pre-combustion chamber structure provided by a specific embodiment of the present invention along a second viewing angle;

[0031] Figure 3 is a structural schematic diagram of a pre-combustion chamber structure provided by a specific embodiment of the present invention along a third viewing angle;

[0032] Figure 4 It is a simulation analysis comparison diagram of the residual exhaust gas amount at the end of scavenging between the pre-combustion chamber structure of the prior art and the pre-combustion chamber structure of the present invention;

[0033] Figure 5 It is a simulation analysis comparison diagram of the fuel gas volume at the ignition moment between the pre-combustion chamber structure of the prior art and the pre-combustion chamber structure of the present invention;

[0034] Figure 6 is a flow chart of an engine control method provided by a specific embodiment of the present invention;

[0035] Figure 7 is a temperature curve of a pre-combustion chamber and a pressure curve of a pre-combustion chamber provided by a specific embodiment of the present invention;

[0036] Figure 8 It is a comparison diagram of residual exhaust gas mass fraction curves of the precombustion chamber structure of the prior art and the precombustion chamber structure of the present invention.

[0037] In the figure:

[0038] 1. Pre-combustion chamber body; 11. Pre-combustion chamber; 111. First sub-chamber; 112. Second sub-chamber; 113. Third sub-chamber; 12. Air intake channel; 121. Sub-air intake channel; 122. Annular channel; 13. Central mounting hole; 14. Air vent;

[0039] 2. Air intake manifold. DETAILED DESCRIPTION

[0040] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0041] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0043] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0044] The present invention provides an engine, which includes a pre-combustion chamber structure, such as Figure 1-3 As shown, the pre-combustion chamber structure includes a pre-combustion chamber body 1, which is provided with a pre-combustion chamber 11 and an air intake passage 12 connected to the pre-combustion chamber 11. Scavenging gas is transported into the pre-combustion chamber 11 through the air intake passage 12, so that the pre-combustion chamber 11 can be scavenged; fuel gas is transported into the pre-combustion chamber 11 through the air intake passage 12, so that the fuel gas in the pre-combustion chamber 11 can ignite the fuel gas in the main combustion chamber, thereby realizing active ignition.

[0045] Preferably, if Figure 1 and Figure 2As shown, the intake channel 12 includes a plurality of sub-intake channels 121, and the plurality of sub-intake channels 121 are divided into a plurality of sub-intake channel groups. The plurality of sub-intake channel groups are distributed at intervals along the height direction of the pre-combustion chamber 11. The plurality of sub-intake channels 121 of each sub-intake channel group are distributed at intervals along the circumference of the pre-combustion chamber 11 and are all connected to the pre-combustion chamber 11. A plurality of sub-intake channels 121 are provided, and the plurality of sub-intake channel groups are spaced apart along the height direction of the pre-combustion chamber 11, so that the coverage area of ​​the intake channel 12 is large, and the scavenging effect on the pre-combustion chamber 11 can be improved, thereby effectively reducing the amount of gas injected into the pre-combustion chamber 11 leaking into the main combustion chamber, thereby improving the working performance of the pre-combustion chamber structure; secondly, the plurality of sub-intake channels 121 of each sub-intake channel group are spaced apart along the circumference of the pre-combustion chamber 11, which can improve the scavenging uniformity, scavenging effect, scavenging efficiency and gas intake efficiency. When gas is injected into the pre-combustion chamber 11, the amount of gas leaking into the main combustion chamber can be effectively reduced, and the uniformity of gas distribution can be effectively improved.

[0046] Further preferably, the plurality of sub-intake channel groups are evenly spaced and distributed along the height direction of the pre-combustion chamber 11. The plurality of sub-intake channels 121 of each sub-intake channel group are evenly spaced and distributed along the circumference of the pre-combustion chamber 11. This is to further improve the scavenging uniformity and the fuel gas distribution uniformity. In this embodiment, the number of sub-intake channel groups is exemplarily set to two, and the two sub-intake channel groups are spaced and distributed along the height direction of the pre-combustion chamber 11.

[0047] More preferably, if Figure 1 and Figure 2 As shown, in two adjacent sub-intake channel groups along the height direction of the pre-combustion chamber 11, the multiple sub-intake channels 121 in one sub-intake channel group and the multiple sub-intake channels 121 in the other sub-intake channel group are staggered in the circumferential direction of the pre-combustion chamber 11. The coverage of the sub-intake channels 121 can be further increased, so that the scavenging uniformity and the fuel gas distribution uniformity can be further improved. As an alternative, in two adjacent sub-intake channel groups along the height direction of the pre-combustion chamber 11, the multiple sub-intake channels 121 in one sub-intake channel group correspond one-to-one with the multiple sub-intake channels 121 in the other sub-intake channel group and are arranged at the same position along the circumference of the pre-combustion chamber 11.

[0048] Preferably, if Figure 1 and Figure 2As shown, the sub-intake channel 121 is arc-shaped. Along the height direction of the pre-combustion chamber 11, the opening of the sub-intake channel 121 faces downward. So that along the height direction of the pre-combustion chamber 11, the gas sprayed into the pre-combustion chamber 11 from each sub-intake channel 121 is inclined downward, which can further improve the scavenging effect and scavenging efficiency. As an alternative, the sub-intake channel 121 can also be set to be straight, and the angle between the direction of the gas flowing from the straight sub-intake channel 121 to the pre-combustion chamber 11 and the direction of the pre-combustion chamber 11 from top to bottom is greater than or equal to 90° and less than 180°. So that along the height direction of the pre-combustion chamber 11, the gas sprayed into the pre-combustion chamber 11 from each sub-intake channel 121 can also be inclined downward, which helps to discharge the exhaust gas generated in the previous cycle in the pre-combustion chamber 11.

[0049] More preferably, if Figure 1 and Figure 2 As shown, along the direction from top to bottom of the pre-combustion chamber 11, the angles corresponding to the multiple sub-intake channel groups gradually increase. As the angles corresponding to the multiple sub-intake channel groups gradually increase, the gas sprayed into the central area of ​​the pre-combustion chamber 11 by each sub-intake channel group is distributed in sequence from top to bottom along the height direction of the pre-combustion chamber 11, thereby further improving the scavenging effect and scavenging efficiency. Among them, the central area of ​​the pre-combustion chamber 11 refers to the area where the central axis of the pre-combustion chamber 11 is located. It can be understood that the direction from top to bottom of the pre-combustion chamber 11, the direction from bottom to top of the pre-combustion chamber 11, the height direction of the pre-combustion chamber 11 and the central axis of the pre-combustion chamber 11 are all parallel.

[0050] Further preferably, the aperture of the sub-intake channel 121 gradually decreases from the input end of the sub-intake channel 121 to the output end of the sub-intake channel 121. It can be understood that the cross-sectional area of ​​the sub-intake channel 121 perpendicular to its own extension direction gradually decreases from the input end of the sub-intake channel 121 to the output end of the sub-intake channel 121. This can effectively increase the speed at which the gas is sprayed from the sub-intake channel 121 into the pre-combustion chamber 11, thereby further improving the scavenging effect and the efficiency of the intake gas. As an alternative, the apertures of the sub-intake channel 121 are equal at all locations along the input end of the sub-intake channel 121 to the output end of the sub-intake channel 121.

[0051] Among them, Figure 1 and Figure 2 As shown, the intake channel 12 further includes an annular channel 122 located in the pre-combustion chamber body 1, and the annular channel 122 is connected to each sub-intake channel 121 of each sub-intake channel group, so that gas can be delivered to the pre-combustion chamber 11 through each sub-intake channel 121 synchronously.

[0052] Specifically, Figure 1-3As shown, the pre-combustion chamber structure further includes an intake manifold 2, one end of which is connected to the annular channel 122, and the other end is used to communicate with the scavenging gas source and the fuel gas source, so as to realize the delivery of scavenging gas and fuel gas into the pre-combustion chamber 11.

[0053] Preferably, the sum of the end surface areas of the output ends of the sub-intake channels 121 is equal to the intake cross-sectional area of ​​the intake manifold 2 perpendicular to its own extension direction, so as to avoid pressure loss caused by conveying gas.

[0054] Preferably, in this embodiment, if Figure 1 and Figure 2 As shown, the pre-combustion chamber 11 includes a spherical first sub-chamber 111, a conical second sub-chamber 112, and a cylindrical third sub-chamber 113. Along the height direction of the pre-combustion chamber 11, the first sub-chamber 111 is connected to the large end of the second sub-chamber 112 and is located above the second sub-chamber 112, and the third sub-chamber 113 is connected to the small end of the second sub-chamber 112 and is located below the second sub-chamber 112. Along the height direction of the pre-combustion chamber 11, the intake channel 12 is located at the top of the first sub-chamber 111. That is, the sub-intake channel 121 and the annular channel 122 are both located at the top of the first sub-chamber 111.

[0055] In the prior art, the gas flow dead zone of the pre-combustion chamber is mainly concentrated at the top of the pre-combustion chamber. Therefore, the first sub-chamber 111 is set to be spherical, and the inner peripheral wall of the spherical shape can guide the gas flow, so that the gas flow dead zone of the pre-combustion chamber 11 can be effectively reduced compared with the prior art, thereby further improving the scavenging effect. Among them, the gas flow dead zone refers to the gas in the local space of the pre-combustion chamber 11 that basically does not participate in the gas flow, but only moves locally in place.

[0056] Specifically, in this embodiment, Figure 4 As shown, the left one is a simulation analysis diagram of the residual exhaust gas volume of the pre-combustion chamber structure before optimization at the end of scavenging, and the right one is a simulation analysis diagram of the residual exhaust gas volume of the pre-combustion chamber structure of the present invention at the end of scavenging. Figure 4 It can be clearly seen that the right pre-combustion chamber structure has significantly fewer dead zones for gas flow than the left pre-combustion chamber structure; secondly, the amount of residual exhaust gas in the area encircled by the dotted circle in the right pre-combustion chamber structure is significantly reduced compared to the corresponding area in the left pre-combustion chamber structure.

[0057] Specifically, in this embodiment, Figure 5 As shown, the left one is a simulation analysis diagram of the gas volume at the ignition time of the pre-combustion chamber structure before optimization, and the right one is a simulation analysis diagram of the gas volume at the ignition time of the pre-combustion chamber structure of the present invention. Figure 5It can be clearly seen that the right pre-combustion chamber structure has significantly fewer gas flow dead zones than the left pre-combustion chamber structure, and the gas is more evenly distributed in the pre-combustion chamber 11.

[0058] As an alternative, the pre-combustion chamber 11 includes a cylindrical first sub-chamber 111, a conical second sub-chamber 112, and a cylindrical third sub-chamber 113. Along the height direction of the pre-combustion chamber 11, the first sub-chamber 111 is connected to the large end of the second sub-chamber 112 and is located above the second sub-chamber 112, and the third sub-chamber 113 is connected to the small end of the second sub-chamber 112 and is located below the second sub-chamber 112. Along the height direction of the pre-combustion chamber 11, the intake passage 12 is located at the top of the first sub-chamber 111.

[0059] Specifically, Figure 1-3 As shown, the top of the pre-combustion chamber body 1 is provided with a central mounting hole 13 connected to the first sub-chamber 111, and the central mounting hole 13 is used to install a spark plug, so as to ignite the gas in the pre-combustion chamber 11. Preferably, the central axis of the central mounting hole 13 is colinear with the central axis of the pre-combustion chamber 11. The annular channel 122 and the plurality of sub-intake channels 121 are distributed on the periphery of the central mounting hole 13.

[0060] Specifically, Figure 1-3 As shown, the bottom end of the pre-combustion chamber body 1 is provided with a vent hole 14 connected to the third sub-chamber 113, and the vent hole 14 is connected to the main combustion chamber of the engine. During scavenging, the exhaust gas in the pre-combustion chamber 11 flows to the main combustion chamber through the vent hole 14 and is discharged from the main combustion chamber. During ignition, the ignited gas in the pre-combustion chamber 11 is sprayed into the main combustion chamber through the vent hole 14, igniting the gas in the main combustion chamber to achieve active ignition.

[0061] Preferably, if Figure 1-3 As shown, there are multiple vent holes 14, and the multiple vent holes 14 are spaced apart along the circumference of the pre-combustion chamber 11 to improve the uniformity of gas injection and the efficiency and reliability of igniting the gas in the main combustion chamber. Further preferably, the multiple vent holes 14 are spaced apart evenly along the circumference of the pre-combustion chamber 11 to further improve the uniformity of gas injection.

[0062] Specifically, in this embodiment, the gas supplied by the scavenging gas source is air. The scavenging gas source is a separately provided air cylinder, and the air intake manifold 2 is used to communicate with the air cylinder and the fuel gas source. As an alternative, the gas supplied by the scavenging gas source is fuel gas.

[0063] Specifically, in this embodiment, the fuel gas supplied by the fuel gas source is methane. The fuel gas source and the fuel gas source of the main combustion chamber are the same fuel gas source. In other embodiments, the fuel gas may also be hydrogen or other hydrocarbons.

[0064] The present invention also provides an engine control method for the engine implemented above. By adopting the engine control method, the scavenging quality and scavenging efficiency of the pre-combustion chamber 11 can be effectively improved, and the ignition efficiency and ignition reliability of the gas in the pre-combustion chamber 11 can be effectively improved.

[0065] like Figure 6 As shown, the engine control method includes:

[0066] S100, determining a limit scavenging crank angle range corresponding to when scavenging the pre-combustion chamber 11 starts according to a preset injection pressure and a preset injection amount.

[0067] Specifically, the preset injection pressure has a value range of 7 bar to 10 bar. The preset injection pressure has a value range based on experience obtained from a large number of previous tests.

[0068] Specifically, the preset injection amount has a range of (0.5%*total gas amount) to (1%*total gas amount). The total gas amount is the total amount of gas injected into the pre-combustion chamber 11 and the main combustion chamber in each working cycle of the engine; the volume of the pre-combustion chamber 11 accounts for 1% to 1.5% of the volume of the main combustion chamber. The preset injection amount has an empirical range obtained from a large number of previous tests.

[0069] It can be understood that, for engines of different specifications, the selected preset injection pressures are the same or different, and the selected preset injection quantities are the same or different.

[0070] Specifically, step S100 includes: according to the preset injection pressure and the preset injection amount, the limit start scavenging crank angle range is retrieved from the table. The table is formed by the preset injection pressure, the preset injection amount and the limit start scavenging crank angle range. The table is an empirical table obtained from a large number of previous tests.

[0071] According to the detected limit scavenging crank angle range, the corresponding scavenging crank angle is limited to avoid starting scavenging in the pre-combustion chamber 11 too early or too late, so as to effectively ensure the scavenging effect of scavenging the pre-combustion chamber 11.

[0072] It is understandable that for engines of different specifications, the corresponding tables are different. The limit start scavenging crank angle range selected according to the preset injection pressure and the preset injection amount is the same or different.

[0073] S200, determining whether the scavenging conditions for the pre-combustion chamber 11 are met based on the temperature of the main combustion chamber, the pressure of the main combustion chamber, the preset injection pressure and the limit scavenging crank angle range.

[0074] Specifically, step S200 includes:

[0075] Determine whether the crankshaft angle is within the limit start scavenging crankshaft angle range; determine whether the temperature of the main combustion chamber is less than or equal to the set temperature; determine whether the pressure difference is greater than or equal to the set scavenging pressure difference. Wherein, pressure difference = preset injection pressure - pressure of the main combustion chamber.

[0076] If the crankshaft angle is within the limit scavenging crankshaft angle range, the temperature of the main combustion chamber is less than or equal to the set temperature, and the pressure difference is greater than or equal to the set scavenging pressure difference, it is determined that the scavenging conditions for the pre-combustion chamber 11 are met.

[0077] S300, starting to scavenge the pre-combustion chamber 11 with a preset injection pressure and a preset injection amount.

[0078] Specifically, when the pressure difference is greater than or equal to the set scavenging pressure difference, it indicates that the pressure of the main combustion chamber is relatively low at this time; when the temperature of the main combustion chamber is less than or equal to the set temperature, it indicates that the temperature of the main combustion chamber is also relatively low at this time. Therefore, when the temperature and pressure of the main combustion chamber are both relatively low, the pre-combustion chamber 11 begins to be scavenged, so that the scavenging gas injected into the pre-combustion chamber 11 can flow efficiently and smoothly from the vent hole 14 into the main combustion chamber after scavenging the pre-combustion chamber 11, and finally be discharged from the main combustion chamber. This effectively improves the scavenging effect and scavenging efficiency of scavenging the pre-combustion chamber 11.

[0079] In this embodiment, the scavenging gas is air. Compared with scavenging the pre-combustion chamber 11 with fuel gas, scavenging the pre-combustion chamber 11 with air can effectively avoid residual fuel gas caused when the pre-combustion chamber 11 is scavenged, thereby facilitating the control of the subsequent injection amount of fuel gas into the pre-combustion chamber 11.

[0080] Specifically, the range of the set temperature is 600K to 800K. It is understandable that the value of the set temperature is at least related to factors such as the engine specifications, the preset injection pressure and the preset injection amount. For different engine specifications, preset injection pressures and preset injection amounts, the values ​​of the set temperature are the same or different. The range of the set temperature is an empirical range obtained from a large number of previous tests.

[0081] Specifically, the scavenging pressure difference is set to a value range of 4 bar to 7 bar. It is understandable that the value of the scavenging pressure difference is at least related to factors such as the engine specifications, the preset injection pressure and the preset injection amount. For different engine specifications, preset injection pressures and preset injection amounts, the values ​​of the scavenging pressure difference are set to be the same or different. The range of the scavenging pressure difference is an empirical range obtained from a large number of previous tests.

[0082] Wherein, after step S300, the method further includes:

[0083] S400, determine whether the pressure difference is less than the set fuel-intake pressure difference. If the pressure difference is less than the set fuel-intake pressure difference, execute step S500.

[0084] S500 , fuel begins to be injected into the pre-combustion chamber 11 at a preset injection pressure and a preset injection amount.

[0085] Specifically, when the pressure difference is less than the set intake and combustion pressure difference, it indicates that the pressure and temperature of the main combustion chamber will gradually increase, and the engine will gradually enter the compression stage. Therefore, when the pressure difference is set to be less than the set intake and combustion pressure difference, the pre-combustion chamber 11 starts to inject gas, so that the amount of gas leaking into the main combustion chamber can be effectively reduced, thereby effectively improving the ignition efficiency and ignition reliability of the gas in the pre-combustion chamber 11.

[0086] Specifically, the value range of the fuel-intake pressure difference is set to (1 bar, 4 bar). That is, the minimum value of the fuel-intake pressure difference is greater than 1 bar, and the maximum value of the fuel-intake pressure difference is less than 4 bar. It can be understood that the value of the fuel-intake pressure difference is at least related to factors such as the engine specifications, preset injection pressure and preset injection amount. For different engine specifications, preset injection pressures and preset injection amounts, the values ​​of the fuel-intake pressure difference are set to be the same or different. The fuel-intake pressure difference range is set to an empirical range obtained from a large number of previous tests.

[0087] Preferably, in this embodiment, the value of the set fuel-intake pressure difference is the same as the value of the set scavenging pressure difference, so that when the scavenging of the pre-combustion chamber 11 is stopped, the pre-combustion chamber 11 starts to inject gas synchronously. In other embodiments, the value of the set fuel-intake pressure difference may be set to be smaller than the value of the set scavenging pressure difference, so that the pre-combustion chamber 11 starts to inject gas after the scavenging of the pre-combustion chamber 11 is stopped for a period of time.

[0088] Specifically, after step S500, the following steps are further included:

[0089] After S600, the process further includes: when the pressure difference is less than or equal to 1 bar, controlling to stop injecting gas into the pre-combustion chamber 11. When the pressure difference is less than or equal to 1 bar, the pressure of the pre-combustion chamber 11 fluctuates and is unstable, which may easily lead to unstable injection of gas into the pre-combustion chamber 11. Therefore, when the pressure difference is less than or equal to 1 bar, controlling to stop injecting gas into the pre-combustion chamber 11.

[0090] Therefore, by adopting this engine control method, the scavenging effect and scavenging efficiency of the pre-combustion chamber 11 can be effectively improved, and the ignition efficiency and ignition reliability of the fuel gas in the pre-combustion chamber 11 can be effectively improved.

[0091] Specifically, in this embodiment, the preset injection pressure is 8 bar, the preset injection amount is (1%*total gas amount), the set temperature is 600K, and the set pressure difference is 4 bar. The crank angle range of scavenging from the limit selected in the table by the preset injection pressure is: -345°CA~-180°CA. Figure 7 It can be seen that when the crankshaft angle is -345°CA, scavenging of the pre-combustion chamber 11 starts; when the crankshaft angle is -180°CA, scavenging of the pre-combustion chamber 11 stops and fuel gas injection into the pre-combustion chamber 11 starts; when the crankshaft angle is -85°CA, fuel gas injection into the pre-combustion chamber 11 stops.

[0092] Specifically, in this embodiment, combined with Figure 7 and Figure 8 It can be seen that the residual exhaust gas mass fraction is reduced by approximately 0.01 at the end of the scavenging of the pre-combustion chamber 11, thereby improving the scavenging effect. The exhaust gas mainly includes carbon dioxide.

[0093] Specifically, in this embodiment, when the injection of the fuel gas is stopped, the amount of fuel gas in the pre-combustion chamber 11 remains substantially unchanged.

[0094] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An engine control method, characterized in that: include: Determining a limit scavenging crank angle range corresponding to when scavenging of the pre-combustion chamber (11) starts according to a preset injection pressure and a preset injection amount; Determining whether the scavenging start condition of the pre-combustion chamber (11) is met based on the temperature of the main combustion chamber, the pressure of the main combustion chamber, the preset injection pressure and the limit scavenging start crank angle range; The pre-combustion chamber (11) begins to be scavenged at the preset injection pressure and the preset injection amount.

2. The engine control method according to claim 1, characterized in that: The step of determining the limit crank angle range for starting scavenging of the pre-combustion chamber (11) according to the preset injection pressure and the preset injection amount comprises: The limit start scavenging crank angle range is retrieved from a table according to the preset injection pressure and the preset injection amount; wherein the table is formed by the preset injection pressure, the preset injection amount and the limit start scavenging crank angle range.

3. The engine control method according to claim 1, characterized in that: The step of determining the conditions for starting scavenging in the pre-combustion chamber (11) according to the temperature of the main combustion chamber, the pressure of the main combustion chamber, the preset injection pressure and the limit scavenging crank angle range comprises: Determine whether the crankshaft angle is within the limit start scavenging crankshaft angle range; determine whether the temperature of the main combustion chamber is less than or equal to the set temperature; determine whether the pressure difference is greater than or equal to the set scavenging pressure difference; the pressure difference = preset injection pressure - pressure of the main combustion chamber; If the crankshaft angle is within the limit scavenging crankshaft angle range, the temperature of the main combustion chamber is less than or equal to the set temperature, and the pressure difference is greater than or equal to the set scavenging pressure difference, it is determined that the scavenging start condition of the pre-combustion chamber (11) is met.

4. The engine control method according to claim 3, characterized in that: The set temperature has a value range of 600K to 800K; The value range of the set scavenging air pressure difference is: 4bar~7bar.

5. The engine control method according to any one of claims 1 to 4, characterized in that: The preset injection pressure has a value range of 7 bar to 10 bar; The value range of the preset injection amount is: (0.5%*total gas amount) to (1%*total gas amount); The total fuel gas volume is the total amount of fuel gas injected into the pre-combustion chamber (11) and the main combustion chamber in each working cycle of the engine; the volume of the pre-combustion chamber (11) accounts for 1% to 1.5% of the volume of the main combustion chamber.

6. The engine control method according to claim 5, characterized in that: The preset injection pressure is 8 bar, the preset injection amount is (1%*total fuel gas amount), and the limit start scavenging crank angle range is: -345°CA to -180°CA.

7. The engine control method according to any one of claims 1 to 4, characterized in that: After the pre-combustion chamber (11) begins to be scavenged with the preset injection pressure and the preset injection amount, the following steps are also included: Determine whether the pressure difference is less than the set intake-combustion pressure difference; the pressure difference = preset injection pressure - the pressure of the main combustion chamber; if the pressure difference is less than the set intake-combustion pressure difference, start injecting fuel into the pre-combustion chamber (11) at the preset injection pressure and the preset injection amount.

8. The engine control method according to claim 7, characterized in that: The value range of the set fuel intake pressure difference is: (1 bar, 4 bar).

9. An engine, comprising a pre-combustion chamber structure, wherein the pre-combustion chamber structure comprises a pre-combustion chamber body (1), wherein the pre-combustion chamber body (1) is provided with a pre-combustion chamber (11) and an intake passage (12) communicating with the pre-combustion chamber (11), wherein: Used to implement the engine control method described in any one of claims 1-8.

10. The engine according to claim 9, characterized in that The pre-combustion chamber (11) comprises a spherical first sub-chamber (111), a conical second sub-chamber (112) and a cylindrical third sub-chamber (113); along the height direction of the pre-combustion chamber (11), the first sub-chamber (111) is connected with the large end of the second sub-chamber (112) and is located above the second sub-chamber (112), and the third sub-chamber (113) is connected with the small end of the second sub-chamber (112) and is located below the second sub-chamber (112); The air intake channel (12) comprises a sub-air intake channel (121) communicating with the first sub-chamber (111); The sub-intake channel (121) is arc-shaped; along the height direction of the pre-combustion chamber (11), the opening of the sub-intake channel (121) faces downward, and the sub-intake channel (121) is located at the top of the first sub-chamber (111).

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