Control method and device for stratified combustion of engine

Abstract

The invention provides a control method and device for stratified combustion of an engine, and relates to the technical field of engines, the method comprises the steps that in the compression stroke stage of the engine, the position of a flow field in an air cylinder of the engine is adjusted according to the lift difference of a plurality of air inlet valves; under the condition that the position of the flow field is located at the target position, the area, with the airflow speed smaller than the preset speed, in the flow field is determined as the center area of the flow field, and the target position is the position away from an oil injector by a preset distance; and the oil injector is controlled to inject fuel oil to the central area, and the spark plug is controlled to ignite. Fuel oil layering is formed in an air cylinder of the engine, and the layering effect of stratified combustion of the engine is improved.

Description

Technical Field

[0001] The present application relates to the field of engine technology, and in particular to a control method and device for engine stratified combustion. Background Art

[0002] In the field of engine technology, stratified combustion mode is a major combustion mode. Compared with homogeneous combustion, it has a larger air-fuel ratio and greatly improves the thermal efficiency of the engine.

[0003] At present, when the center-mounted fuel injector is combined with the preset ignition strategy, a higher fuel concentration is formed near the spark plug before the top dead center ignition, which can achieve stable ignition and gradually reduce the air-fuel ratio outward to form a stratified effect. However, with the demand for engine miniaturization, the side-mounted fuel injector has become the mainstream setting mode of the fuel injector in the engine. One way to achieve stratified combustion under the side-mounted fuel injector setting mode is to use the structural setting of the fuel injector to directly spray fuel to the position of the spark plug to form a higher fuel concentration near the spark plug, but this method can only ensure the formation of a high concentration of fuel in a smaller range, and the stratified effect of stratified combustion is not good.

[0004] Therefore, when the fuel injector in the engine is a side-mounted fuel injector, how to improve the stratified effect of the engine stratified combustion is an urgent problem to be solved. Summary of the invention

[0005] In order to solve the problem that the stratification effect of engine stratified combustion is poor when the injector in the engine is a side-mounted injector, the embodiments of the present application provide a control method, device, electronic device and computer-readable storage medium for engine stratified combustion to improve the stratification effect of engine stratified combustion.

[0006] In a first aspect, an embodiment of the present application provides a method for controlling stratified combustion of an engine, comprising:

[0007] During the compression stroke of the engine, adjusting the position of the flow field in the cylinder of the engine according to the lift difference of multiple intake valves;

[0008] When the position of the flow field is at a target position, determining a region in the flow field where the airflow velocity is less than a preset velocity as a central region of the flow field, wherein the target position is a position at a preset distance from the injector;

[0009] The fuel injector is controlled to spray fuel toward the central area, and the spark plug is controlled to ignite.

[0010] As an optional implementation of the embodiment of the present application, controlling the fuel injector to inject fuel toward the central area includes:

[0011] Determining injection parameters according to the lift differences of the plurality of intake valves and the operating parameters of the engine; the operating parameters of the engine include: the engine speed and the intake pressure of the intake valve, and the injection parameters include injection timing and injection control parameters;

[0012] When the injection timing is reached, the injector is controlled according to the injection control parameter to inject fuel toward the central area.

[0013] As an optional implementation of the embodiment of the present application, the injection timing includes a target crankshaft angle of the engine, and the injection control parameters include: the injection pressure of the injector, the amount of injected fuel, and the injection duration of the injected fuel;

[0014] When the injection timing is reached, controlling the injector to inject fuel toward the central area according to the injection control parameter comprises:

[0015] When the crankshaft angle of the engine reaches the target crankshaft angle, the injector is controlled to inject fuel into the central area under the injection pressure, and the amount of fuel injected within the injection duration is controlled to be the injected fuel amount.

[0016] As an optional implementation of the embodiment of the present application, when the position of the flow field is at the target position, determining the area in the flow field where the airflow speed is less than a preset speed as the central area of ​​the flow field includes:

[0017] When the flow field is at a target position, the flow field is sliced ​​along a direction perpendicular to the spray axis of the injector, and the air flow velocity in the central area of ​​the obtained flow field slice is smaller than the air flow velocity in the edge area of ​​the flow field slice;

[0018] An area in the flow field slice where the airflow velocity is less than a preset velocity is determined as the central area of ​​the flow field.

[0019] As an optional implementation of the embodiment of the present application, the method further includes:

[0020] Calculating a preset air-fuel ratio range according to the power of the engine, fuel consumption information of a vehicle corresponding to the engine, and an exhaust emission standard of the vehicle;

[0021] The target crank angle is determined based on the preset air-fuel ratio range, the intake pressures of the plurality of intake valves, and the injection control parameter.

[0022] As an optional implementation of the embodiment of the present application, the method further includes:

[0023] Obtain simulation results corresponding to three-dimensional fluid simulation experiments;

[0024] The target position corresponding to the flow field is determined in the simulation result according to the lift differences of the plurality of intake valves.

[0025] In a second aspect, an embodiment of the present application provides a control device for stratified combustion of an engine, the device comprising:

[0026] An adjustment module, used for adjusting the position of the flow field in the cylinder of the engine according to the lift difference of multiple intake valves during the compression stroke of the engine;

[0027] a determination module, configured to determine, when the position of the flow field is at a target position, a region in the flow field where the airflow velocity is less than a preset velocity as a central region of the flow field, wherein the target position is a position at a preset distance from the injector;

[0028] The control module is used to control the fuel injector to inject fuel into the central area and control the spark plug to ignite.

[0029] As an optional implementation of the embodiment of the present application, the control module is specifically used to determine the injection parameters according to the lift difference of the multiple intake valves and the operating parameters of the engine; the operating parameters of the engine include: the speed of the engine and the intake pressure of the intake valve, and the injection parameters include injection timing and injection control parameters;

[0030] When the injection timing is reached, the injector is controlled according to the injection control parameter to inject fuel toward the central area.

[0031] As an optional implementation of the embodiment of the present application, the injection timing includes a target crankshaft angle of the engine, and the injection control parameters include: the injection pressure of the injector, the amount of injected fuel, and the injection duration of the injected fuel;

[0032] The control module is specifically used to control the injector to inject fuel into the central area under the injection pressure when the crankshaft angle of the engine reaches the target crankshaft angle, and control the amount of fuel injected within the injection duration to be the injected fuel amount.

[0033] As an optional implementation of the embodiment of the present application, the determination module is specifically used to slice the flow field in a direction perpendicular to the spray axis of the injector when the position of the flow field is at the target position, so that the air flow velocity in the central area of ​​the obtained flow field slice is less than the air flow velocity in the edge area of ​​the flow field slice;

[0034] An area in the flow field slice where the airflow velocity is less than a preset velocity is determined as the central area of ​​the flow field.

[0035] As an optional implementation of the embodiment of the present application, the device further includes:

[0036] A calculation module, used to calculate a preset air-fuel ratio range according to the power of the engine, the fuel consumption information of the vehicle corresponding to the engine, and the exhaust emission standard of the vehicle;

[0037] The target crank angle is determined based on the preset air-fuel ratio range, the intake pressures of the plurality of intake valves, and the injection control parameter.

[0038] As an optional implementation of the embodiment of the present application, the device further includes:

[0039] An acquisition module is used to obtain simulation results corresponding to a three-dimensional fluid simulation experiment;

[0040] The target position corresponding to the flow field is determined in the simulation result according to the lift differences of the plurality of intake valves.

[0041] In a third aspect, an embodiment of the present application provides an electronic device, comprising: a memory and a processor, wherein the processor is used to execute the engine stratified combustion control method described in the first aspect or any optional implementation of the first aspect when calling a computer program.

[0042] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method for controlling engine stratified combustion described in the first aspect or any optional embodiment of the first aspect is implemented.

[0043] In a fifth aspect, an embodiment of the present application provides a vehicle, characterized in that the vehicle is equipped with the engine stratified combustion control device described in the third aspect or the electronic device described in the fifth aspect or the storage medium described in the seventh aspect.

[0044] Compared with the prior art, the technical solution provided by the embodiments of the present application has the following advantages:

[0045] In the control method of engine stratified combustion provided in the embodiment of the present application, during the compression stroke stage of the engine, the position of the flow field in the cylinder of the engine is adjusted according to the lift difference of multiple intake valves; when the position of the flow field is at the target position, the area in the flow field where the airflow velocity is less than the preset velocity is determined as the central area of ​​the flow field, wherein the target position is a position at a preset distance from the injector; the injector is controlled to inject fuel to the central area, and the spark plug is controlled to ignite. Since the airflow velocity in the central area is small and less than the preset velocity when injecting fuel to the central area, the fuel spray can be kept on the spray axis of the injector and slowly evaporate and diffuse, forming an effect of high fuel concentration in the central area and gradually decreasing concentration outward, forming fuel stratification, and improving the stratification effect of engine stratified combustion. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0047] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0048] Figure 1 A flow chart of a method for controlling engine stratified combustion according to one or more embodiments of the present application;

[0049] Figure 2 A schematic diagram of the structure of a cylinder provided according to one or more embodiments of the present application;

[0050] Figure 3 A schematic diagram of a flow field in a cylinder provided by an embodiment of the present application;

[0051] Figure 4 A schematic diagram of a flow field in a cylinder provided by an embodiment of the present application;

[0052] Figure 5 A schematic diagram of the central area of ​​a flow field in one embodiment of the present application;

[0053] Figure 6 A structural block diagram of a control device for engine stratified combustion provided by one or more embodiments of the present application;

[0054] Figure 7 A structural block diagram of a control device for engine stratified combustion provided by one or more embodiments of the present application;

[0055] Figure 8 The present invention is a diagram of the internal structure of an electronic device provided according to one or more embodiments of the present application. DETAILED DESCRIPTION

[0056] In order to make the purpose, implementation mode and advantages of the present application clearer, the exemplary implementation mode of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0057] Based on the exemplary embodiments described in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the claims attached to this application. In addition, although the disclosure in this application is introduced according to one or several exemplary examples, it should be understood that each aspect of these disclosures can also constitute a complete implementation method separately. It should be noted that the brief description of the terms in this application is only for the convenience of understanding the implementation methods described below, and is not intended to limit the implementation methods of this application. Unless otherwise specified, these terms should be understood according to their common and usual meanings.

[0058] First, the application scenario of the embodiment of the present application is described. The engine has multiple combustion modes, including homogeneous combustion, stratified combustion, etc. Among them, the stratified combustion mode is a main combustion mode. Compared with homogeneous combustion, it can achieve a larger air-fuel ratio and greatly improve the thermal efficiency of the engine. The engine adopting the stratified combustion mode usually adopts a center-mounted injector, but when the engine adopts the center-mounted injector to achieve stratified combustion, it is mainly achieved by the combustion chamber structure and the spark plug, and the setting is relatively solid. When the engine usually adopts a side-mounted injector, it can effectively interact with the airflow and does not occupy the top space of the combustion chamber, which is conducive to the miniaturization of the engine. However, it is difficult to achieve stratified combustion of the engine using a side-mounted injector. If it depends on the setting structure of the cylinder to spray fuel to the spark plug position, stratified combustion can only be achieved under specific oil pressure and load, which is not universal, and the injected fuel does not match the airflow, which can only ensure a high concentration of fuel in a small range. The fuel concentration is greatly affected by the airflow, and the stratification effect is not good.

[0059] Based on this, an embodiment of the present application provides a control method and device for stratified combustion of an engine, wherein the method forms a lift difference by setting intake valves with different lifts in the cylinder of the engine, so that a coupled flow field of a tumble flow field and a vortex flow field is formed in the cylinder. During the movement of the flow field, a central area where the air flow velocity is less than a preset velocity will appear. When the injector is controlled to spray fuel into the central area, the fuel in the central area will not diffuse rapidly with the air flow, but will remain in the center of the cylinder, thereby forming a stratified effect in which the fuel concentration is high in the center of the cylinder and the fuel concentration gradually decreases from the center to the outside, thereby improving the stratified combustion effect of the engine.

[0060] The control method for engine stratified combustion provided in the embodiment of the present application can be executed by the electronic device provided in the embodiment of the present application, or by the control device for engine stratified combustion provided in the embodiment of the present application, or by one or more functional entities on the vehicle, which is not specifically limited in the embodiment of the present application.

[0061] The following is a detailed description of the engine stratified combustion control method provided in the embodiments of the present application through several specific examples.

[0062] Figure 1 The control method flow chart of the engine stratified combustion provided in the embodiment of the present application is shown in FIG. Figure 1 As shown, the control method for stratified combustion of a vehicle engine provided in this embodiment includes the following steps:

[0063] S11. During the compression stroke of the engine, adjusting the position of the flow field in the cylinder of the engine according to the lift difference of a plurality of intake valves.

[0064] For example, the intake valve may be two or three, etc., which is not specifically limited in the present embodiment. Figure 2 middle, Figure 2 A schematic diagram of the structure of a cylinder provided for an embodiment of the present application, wherein 21 and 22 are intake valves, 23 and 24 are exhaust valves, and the dual intake valves in the embodiment of the present application have a valve lift difference. Under different operating conditions of the engine, the crankshaft angles for forming tumble flow fields and vortex flow fields may be different, and the principle of generating the vortex flow field is the horizontal plane component brought about by the different lifts of the dual valves.

[0065] The flow field is the flow field formed by the intake air passing through the multiple intake valves of the cylinder. The lift difference of the multiple intake valves is different, and the position of the formed flow field may be different. When the multiple intake valves have a lift difference, in addition to forming a tumble flow field with the Y axis as the central axis direction, a vortex flow field with the Z axis as the central axis will also be formed. Figure 3As shown in FIG. 1 , as the piston moves in the cylinder, the coupled flow field will rotate with the Y-axis as the center axis. Before the compression top dead center, a tumble cross-cutting flow field with the X-axis as the center axis and a certain offset angle θ is formed. Figure 4 shown.

[0066] S12. When the flow field is at a target position, a region in the flow field where the airflow velocity is less than a preset velocity is determined as a central region of the flow field.

[0067] The target position is a position at a preset distance from the injector, and the injector is a side injector. Figure 3 The position of the injector on the cylinder shown in FIG. 1 is shown with the intake valve as a double intake valve. When in the target position, the vortex center of the flow field is perpendicular to the fuel spray sprayed by the side injector. In order to determine the target position more accurately, the position of the flow field in the cylinder of the engine can be adjusted in combination with controlling the airflow size of the intake port.

[0068] Among them, the determination of the target position can be obtained through a three-dimensional fluid simulation experiment, such as performing a simulation experiment through the CONVERGE three-dimensional fluid simulation software, determining the engine's operating conditions and working parameters, and controlling the engine's operating conditions and working parameters to perform a three-dimensional fluid simulation experiment, wherein the engine's operating parameters include: the engine's rotation speed and the intake pressure of the intake valve. For example, taking a 1.5T mainstream four-stroke control engine as an example, the engine's rotation speed is controlled to be 3000rpm, and the intake pressure of the intake valve is 1.55bar. A three-dimensional fluid simulation experiment is performed. During the intake stroke of the engine, at 496°aTDC, a structural tumble flow field with the Y-axis as the central axis and a structural vortex flow field with the Z-axis as the central axis can be formed, with reference to Figure 2 As shown, the lift of the dual intake valves is different, resulting in different components of the tumble flow horizontal plane, forming a vortex, and then forming a coupled flow field of tumble flow and vortex. In this three-dimensional fluid simulation experiment, the lift difference of the intake valve is adjusted. Under the action of the horizontal vortex component, the flow field in the cylinder continues to rotate from the intake stroke. Near 636°aTDC of the compression stroke, the tumble flow field centered on the Y axis rotates to the tumble flow field centered on the X axis. As the piston continues to compress upward, the flow field in the cylinder is sliced. The principle of slicing is perpendicular to the injector spray axis. The air flow velocity in the center of the slice is small, and it is surrounded by strong tumble flow. In this example, the preset velocity can be 20m / s, that is, the area with air flow velocity V<20m / s is determined as the central area.

[0069] The position of the flow field is determined as the target position. In the actual operation of the engine, the target position of the flow field can be determined according to the preset distance, that is, according to the simulation results of the three-dimensional fluid simulation experiment, the corresponding relationship between the engine's operating parameters, the lift difference of multiple intake valves and the target position or the preset distance can be established. Therefore, based on the corresponding relationship, when the lift difference of the intake valve is adjusted, the target position can be determined accordingly.

[0070] Exemplarily, when determining the target position, a simulation result corresponding to a three-dimensional fluid simulation experiment is obtained; and the target position corresponding to the flow field is determined in the simulation result according to the lift difference of a plurality of intake valves.

[0071] Exemplarily, when the central area is determined periodically, when the position of the flow field is at the target position, the flow field is sliced ​​along a direction perpendicular to the spray axis of the injector, and the air flow velocity in the central area of ​​the obtained flow field slice is less than the air flow velocity in the edge area of ​​the flow field slice, then the area in the flow field slice where the air flow velocity is less than the preset velocity is determined as the central area of ​​the flow field.

[0072] S13, controlling the fuel injector to spray fuel toward the central area, and controlling the spark plug to ignite.

[0073] The spark plug is arranged at the center of the cylinder head of the cylinder. The fuel injector in the embodiment of the present application may be a single-hole high-pressure fuel injector. The schematic diagram of the position of the central area 41 is shown in FIG. Figure 5 As shown, exemplarily, the injection parameters are determined based on the lift difference of the multiple intake valves and the operating parameters of the engine, wherein the operating parameters of the engine include: the engine speed and the intake pressure of the intake valve, and the injection parameters include injection timing and injection control parameters; when the injection timing is reached, the injector is controlled according to the injection control parameters to spray fuel into the central area.

[0074] The injection timing can be determined according to the crankshaft angle. For example, the injection timing includes the target crankshaft angle of the engine. The injection control parameters include: the injection pressure of the injector, the amount of injected fuel, and the injection duration of the injected fuel. The injection duration can be timed according to the crankshaft angle.

[0075] Then, when the injection timing is reached, the injector is controlled to inject fuel to the central area according to the injection control parameters, including: when the crankshaft angle of the engine reaches the target crankshaft angle, the injector is controlled to inject fuel to the central area under the injection pressure, and the amount of fuel injected within the injection duration is controlled to be the injected fuel amount, and when the injected fuel amount reaches the injected fuel amount, the injection of fuel is controlled to be stopped.

[0076] Following the above example, taking a 1.5T mainstream four-stroke control engine as an example, the engine speed is controlled to be 3000rpm, the intake pressure of the intake valve is 1.55bar, and a three-dimensional fluid simulation experiment is performed. In the intake stroke of the engine, at 496°aTDC, a structural tumble flow field with the Y axis as the central axis and a structural vortex flow field with the Z axis as the central axis can be formed. Figure 2 As shown in the figure, the lift of the dual intake valves is different, which makes the horizontal component of the tumble flow different, forming a vortex, and then forming a coupled flow field of tumble flow and vortex. In this three-dimensional fluid simulation experiment, the lift difference of the intake valve is adjusted. Under the action of the horizontal vortex component, the flow field in the cylinder continues to rotate from the intake stroke. Near 636°aTDC of the compression stroke, the tumble flow field centered on the Y axis rotates to the tumble flow field centered on the X axis. The effect of stratified combustion is verified by three-dimensional fluid simulation experiments, combined with Figure 2 As shown, in this three-dimensional fluid simulation experiment, the area with air flow velocity V<20m / s is determined as the central area, the target crankshaft angle is 660°aTDC, the injection pressure is controlled to be 350bar, the fuel injection is 11CAD, and the injection fuel amount is 1.6mg. The results of the three-dimensional fluid simulation experiment show that the central area with air flow velocity V<20m / s, the spray pressure is 350bar, and the fuel is injected into the cylinder at 660°aTDC. At this time, the fuel is injected into the weak speed area, and the fuel in this area will not diffuse rapidly with the flow, but remain in the center of the cylinder. That is, when the crankshaft angle of the engine reaches the target crankshaft angle, the injector is controlled to inject fuel into the central area under the injection pressure, and the amount of fuel injected within the injection time is controlled to be the injection fuel amount. The spray formed by the injection during the injection process is not changed by the traditional tumble and vortex flow field, but continues to evaporate and diffuse slowly on the spray axis, forming an effect of high fuel concentration in the central area and gradually decreasing concentration outward. For example, the equivalence ratio of fuel to air in the central area is 1.25, and it is 1.18, 1.21, 1.06, 0.99, 0.93, etc. outwards, and the concentration of fuel gradually decreases.

[0077] Therefore, during the actual operation of the engine, when the flow field is at the target position, the injector is controlled to spray fuel toward the central area, and the spark plug is controlled to ignite. This allows the fuel spray to remain on the axis and evaporate and diffuse slowly, forming a stratified effect in which the fuel concentration is high in the center of the cylinder and gradually decreases outward, thereby improving the stratified effect of the engine and the effect of stratified combustion.

[0078] In the above embodiment, the injection timing includes the target crankshaft angle of the engine, and the target crankshaft angle can be determined in the following manner: calculating a preset air-fuel ratio range based on the power of the engine, the fuel consumption information of the vehicle corresponding to the engine, and the exhaust emission standard of the vehicle; determining the target crankshaft angle based on the preset air-fuel ratio range, the intake pressure of the multiple intake valves, and the injection control parameters.

[0079] Among them, when the fuel is injected at the target crankshaft angle, the effect of stratified combustion is the best, and the effect of stratified combustion can be measured by the content of each gas component in the exhaust gas emitted by the engine combustion. The preset air-fuel ratio range is related to the working conditions of the engine, such as the power of the engine, and is also related to the fuel consumption information of the vehicle, the exhaust emission standard of the vehicle, etc., because at different air-fuel ratios, the content of each gas component in the exhaust gas emitted by the engine combustion is different.

[0080] Among them, the crankshaft angle of the engine can be monitored in real time by acquiring the monitoring data of the crankshaft position sensor to determine whether the target crankshaft angle has been reached, and the fuel consumption information of the vehicle corresponding to the engine can be acquired, including: collecting the monitoring data of the accelerator pedal sensor of the vehicle; and acquiring the fuel consumption information of the vehicle by processing the monitoring data of the accelerator pedal sensor.

[0081] By injecting fuel at the target crankshaft angle and controlling the spark plug ignition, stratified combustion has the best effect, which can make the exhaust gas emitted by the vehicle meet the exhaust emission standards and reduce pollution to the environment.

[0082] In the control method of engine stratified combustion provided in the embodiment of the present application, during the compression stroke stage of the engine, the position of the flow field in the cylinder of the engine is adjusted according to the lift difference of multiple intake valves; when the position of the flow field is at the target position, the area in the flow field where the airflow velocity is less than the preset velocity is determined as the central area of ​​the flow field, wherein the target position is a position at a preset distance from the injector; the injector is controlled to inject fuel to the central area, and the spark plug is controlled to ignite. Since the airflow velocity in the central area is small and less than the preset velocity when injecting fuel to the central area, the fuel spray can be kept on the spray axis of the injector and slowly evaporate and diffuse, forming an effect of high fuel concentration in the central area and gradually decreasing concentration outward, forming fuel stratification, and improving the stratification effect of engine stratified combustion.

[0083] It should be noted that when controlling the position of the flow field in the cylinder, utilizing the lift difference of multiple intake valves is one feasible method. It can also be achieved by designing the airway, the airway vortex valve, the airway tumble valve, etc.

[0084] Based on the same inventive concept, as an implementation of the above-mentioned method, an embodiment of the present application also provides a control device for executing the engine stratified combustion provided by the above-mentioned embodiment. The device embodiment corresponds to the above-mentioned method embodiment. For ease of reading, the present device embodiment will no longer repeat the details of the above-mentioned method embodiment one by one, but it should be clear that the control device for the engine stratified combustion in this embodiment can correspond to all the contents in the above-mentioned method embodiment.

[0085] Reference Figure 6 As shown, Figure 6 This is a structural block diagram of a control device for stratified combustion of an engine provided in an embodiment of the present application. The control device 600 for stratified combustion of an engine includes:

[0086] An adjustment module 610, configured to adjust the position of the flow field in the cylinder of the engine according to the lift difference of a plurality of intake valves during the compression stroke of the engine;

[0087] A determination module 620, configured to determine, when the position of the flow field is at a target position, a region in the flow field where the airflow velocity is less than a preset velocity as a central region of the flow field, wherein the target position is a position at a preset distance from the injector;

[0088] The control module 630 is used to control the injector to inject fuel into the central area and control the spark plug to ignite.

[0089] As an optional implementation of the embodiment of the present application, the control module 630 is specifically used to determine the injection parameters according to the lift difference of the multiple intake valves and the operating parameters of the engine; the operating parameters of the engine include: the engine speed and the intake pressure of the intake valve, and the injection parameters include injection timing and injection control parameters; when the injection timing is reached, the injector is controlled to spray fuel into the central area according to the injection control parameters.

[0090] As an optional implementation of the embodiment of the present application, the injection timing includes the target crankshaft angle of the engine, and the injection control parameters include: the injection pressure of the injector, the injected fuel amount, and the injection duration of the injected fuel; the control module 630 is specifically used to control the injector to inject fuel to the central area under the injection pressure when the crankshaft angle of the engine reaches the target crankshaft angle, and control the fuel amount injected within the injection duration to be the injected fuel amount.

[0091] As an optional implementation of the embodiment of the present application, the determination module 620 is specifically used to slice the flow field along a direction perpendicular to the spray axis of the injector when the position of the flow field is at the target position, so that the air flow velocity in the central area of ​​the flow field slice is smaller than the air flow velocity in the edge area of ​​the flow field slice; and determine the area in the flow field slice where the air flow velocity is smaller than the preset velocity as the central area of ​​the flow field.

[0092] Figure 7 A structural block diagram of a control device for stratified combustion of an engine provided in another embodiment of the present application, Figure 6 Based on the device shown, it also includes:

[0093] The calculation module 710 is used to calculate a preset air-fuel ratio range according to the power of the engine, the fuel consumption information of the vehicle corresponding to the engine, and the exhaust emission standard of the vehicle; and determine the target crankshaft angle based on the preset air-fuel ratio range, the intake pressure of the multiple intake valves, and the injection control parameters.

[0094] As an optional implementation of the embodiment of the present application, the device further includes:

[0095] The acquisition module 720 is used to acquire simulation results corresponding to the three-dimensional fluid simulation experiment; and determine the target position corresponding to the flow field in the simulation results according to the lift differences of multiple intake valves.

[0096] The control device for engine stratified combustion provided by the embodiment of the present application, when executing the control method for engine stratified combustion, adjusts the position of the flow field in the cylinder of the engine according to the lift difference of multiple intake valves during the compression stroke stage of the engine; when the position of the flow field is at the target position, determines the area in the flow field where the airflow velocity is less than the preset velocity as the central area of ​​the flow field, wherein the target position is a position at a preset distance from the injector; controls the injector to spray fuel to the central area, and controls the spark plug to ignite. Since the airflow velocity in the central area is small and less than the preset velocity when the fuel is sprayed to the central area, the fuel spray can be kept on the spray axis of the injector and evaporate and diffuse slowly, forming an effect of high fuel concentration in the central area and gradually decreasing concentration outward, forming fuel stratification, and improving the stratification effect of engine stratified combustion.

[0097] In one embodiment, an electronic device is provided, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of any one of the engine stratified combustion control methods described in the above method embodiments are implemented.

[0098] When the electronic device provided in the embodiment of the present application performs the control method of engine stratified combustion, during the compression stroke stage of the engine, the position of the flow field in the cylinder of the engine is adjusted according to the lift difference of multiple intake valves; when the position of the flow field is at the target position, the area in the flow field where the airflow velocity is less than the preset velocity is determined as the central area of ​​the flow field, wherein the target position is a position at a preset distance from the injector; the injector is controlled to inject fuel to the central area, and the spark plug is controlled to ignite. Since the airflow velocity in the central area is small and less than the preset velocity when injecting fuel to the central area, the fuel spray can be kept on the spray axis of the injector and slowly evaporate and diffuse, forming an effect of high fuel concentration in the central area and gradually decreasing concentration outward, forming fuel stratification, and improving the stratification effect of engine stratified combustion.

[0099] For example, Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. Figure 8 As shown, the electronic device provided in this embodiment includes: a memory 81 and a processor 82, the memory 81 is used to store computer programs; the processor 82 is used to execute the steps of the engine stratified combustion control method provided in the above method embodiment when calling the computer program, and its implementation principle and technical effect are similar, which will not be repeated here. Those skilled in the art can understand that Figure 7 The structure shown in the figure is merely a block diagram of a partial structure related to the scheme of the present application, and does not constitute a limitation on the electronic device to which the scheme of the present application is applied. The specific electronic device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0100] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of any one of the engine stratified combustion control methods described in the above method embodiments are implemented.

[0101] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory or optical memory, etc. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in various forms, such as static random access memory (SRAM) and dynamic random access memory (DRAM).

[0102] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0103] For the convenience of explanation, the above description has been made in conjunction with specific embodiments. However, the above discussion in some embodiments is not intended to be exhaustive or limit the embodiments to the specific forms disclosed above. According to the above teachings, various modifications and variations can be obtained. The selection and description of the above embodiments are to better explain the principles and practical applications, so that those skilled in the art can better use the embodiments and various different variations of the embodiments suitable for specific use considerations.

Claims

1. A control method for engine stratified combustion, characterized in that: The method comprises: During the compression stroke of the engine, adjusting the position of the flow field in the cylinder of the engine according to the lift difference of multiple intake valves; When the position of the flow field is at a target position, determining a region in the flow field where the airflow velocity is less than a preset velocity as a central region of the flow field, wherein the target position is a position at a preset distance from the injector; The fuel injector is controlled to spray fuel toward the central area, and the spark plug is controlled to ignite.

2. The method according to claim 1, characterized in that The step of controlling the fuel injector to inject fuel toward the central area includes: Determining injection parameters according to the lift differences of the plurality of intake valves and the operating parameters of the engine; the operating parameters of the engine include: the engine speed and the intake pressure of the intake valve, and the injection parameters include injection timing and injection control parameters; When the injection timing is reached, the injector is controlled according to the injection control parameter to inject fuel toward the central area.

3. The method according to claim 2, characterized in that The injection timing includes a target crankshaft angle of the engine, and the injection control parameters include: the injection pressure of the injector, the amount of injected fuel, and the injection duration of the injected fuel; When the injection timing is reached, controlling the injector to inject fuel toward the central area according to the injection control parameter comprises: When the crankshaft angle of the engine reaches the target crankshaft angle, the injector is controlled to inject fuel into the central area under the injection pressure, and the amount of fuel injected within the injection duration is controlled to be the injected fuel amount.

4. The method according to claim 1, characterized in that When the position of the flow field is at the target position, determining the area in the flow field where the airflow speed is less than a preset speed as the central area of ​​the flow field includes: When the flow field is at a target position, the flow field is sliced ​​along a direction perpendicular to the spray axis of the injector, and the air flow velocity in the central area of ​​the obtained flow field slice is smaller than the air flow velocity in the edge area of ​​the flow field slice; An area in the flow field slice where the airflow velocity is less than a preset velocity is determined as the central area of ​​the flow field.

5. The method according to claim 3, characterized in that: The method further comprises: Calculating a preset air-fuel ratio range according to the power of the engine, fuel consumption information of a vehicle corresponding to the engine, and an exhaust emission standard of the vehicle; The target crank angle is determined based on the preset air-fuel ratio range, the intake pressures of the plurality of intake valves, and the injection control parameter.

6. The method according to claim 5, characterized in that The method further comprises: Obtain simulation results corresponding to three-dimensional fluid simulation experiments; The target position corresponding to the flow field is determined in the simulation result according to the lift differences of the plurality of intake valves.

7. A control device for engine stratified combustion, characterized in that: The cylinder of the engine includes a dual intake valve, and the device includes: An adjustment module, used for adjusting the position of the flow field in the cylinder according to the lift difference of multiple intake valves during the compression stroke stage of the engine; a determination module, configured to determine, when the position of the flow field is at a target position, a region in the flow field where the airflow velocity is less than a preset velocity as a central region of the flow field, wherein the target position is a position at a preset distance from the injector; The control module is used to control the fuel injector to inject fuel into the central area and control the spark plug to ignite.

8. An electronic device, comprising: A memory and a processor, wherein the memory stores a computer program, and wherein the processor implements the engine stratified combustion control method according to any one of claims 1 to 6 when executing the computer program.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the engine stratified combustion control method according to any one of claims 1 to 6 is implemented.

10. A vehicle, characterized in that: The vehicle is provided with the engine stratified combustion control device according to claim 7, or the electronic device according to claim 8, or the storage medium according to claim 9.

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