Fuel oil control method and device of multi-cylinder engine and computer readable storage medium

Abstract

The invention discloses a fuel oil control method and device of a multi-cylinder engine and a computer readable storage medium, and belongs to the field of engine control. A first air pressure value of a first load sensor (located on an air inlet branch of a single appointed air cylinder) and a second air pressure value of a second load sensor (located on a total air inlet pipeline of each air cylinder) can be synthesized to determine the air inlet pressure of the air cylinder, so that the target oil injection quantity of the air cylinder is determined and the oil injection quantity is controlled; the air inlet pressure of a single air cylinder can be comprehensively determined based on the air pressure values of the two load sensors at different positions, and the detection precision of the second load sensor is improved through the design of the one-way valve, so that the air inlet pressure of each air cylinder in the multi-cylinder engine and the corresponding air inlet amount can be accurately determined, and fuel control is carried out; therefore, the air-fuel ratio of each cylinder can reach the theoretical optimal interval, and the emission performance and the fuel economy of the engine are optimized.

Description

Technical Field

[0001] This invention relates to the field of engine control, and in particular to a fuel control method, apparatus, and computer-readable storage medium for a multi-cylinder engine. Background Technology

[0002] The actual air-fuel ratio of an engine has a direct impact on emissions performance and fuel economy. To ensure that the actual air-fuel ratio of the engine reaches the theoretically optimal range, the amount of fuel injected into each cylinder needs to be controlled based on the intake air volume of the cylinders in the engine. However, there is a lack of mature fuel control methods in related technologies. Because it is difficult to accurately determine the intake air volume of each cylinder in a multi-cylinder engine, the air-fuel ratio of each cylinder in the engine is also difficult to reach the theoretically optimal range during fuel control, resulting in poor emissions performance and fuel economy of the engine.

[0003] Therefore, how to provide a solution to the above-mentioned technical problems is a problem that needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide a fuel control method, device, and computer-readable storage medium for a multi-cylinder engine. This invention includes a first load sensor installed in the intake branch of a single designated cylinder, and a second load sensor installed in the main intake manifold of all cylinders. When any cylinder is in its intake stroke, the first pressure value from the first load sensor and the second pressure value from the second load sensor can be combined to determine the intake pressure of that cylinder. Then, based on the intake volume corresponding to that intake pressure, the target fuel injection quantity for that cylinder is determined and fuel injection quantity control is performed. Because the intake pressure of a single cylinder can be determined by combining the pressure values ​​from two load sensors at different locations, and the design of the one-way valve improves the detection accuracy of the second load sensor, this invention can accurately determine the intake pressure and corresponding intake volume of each cylinder in a multi-cylinder engine and perform fuel control. This helps to achieve the theoretically optimal air-fuel ratio for each cylinder, thereby optimizing the engine's emission performance and fuel economy.

[0005] To solve the above-mentioned technical problems, the present invention provides a fuel control method for a multi-cylinder engine, comprising: Identify the intake stroke of each cylinder in a multi-cylinder engine; For any cylinder, when the cylinder is in the intake stroke, the intake pressure of the cylinder is determined according to the first pressure value of the first load sensor and the second pressure value of the second load sensor. The first load sensor is installed in the intake branch of a single designated cylinder in the multi-cylinder engine, and the second load sensor is installed in the main intake pipe of each cylinder in the multi-cylinder engine. Each cylinder's intake branch is equipped with a one-way valve that leads from the main intake pipe to the cylinder. The target fuel injection quantity of the cylinder is determined based on the intake air volume corresponding to the intake pressure of the cylinder, so as to control the fuel injection quantity.

[0006] On the other hand, for any cylinder, when the cylinder is in the intake stroke, determining the intake pressure of the cylinder based on the first pressure value of the first load sensor and the second pressure value of the second load sensor includes: For any cylinder, when the cylinder is in the intake stroke, the minimum air pressure value of the first load sensor in the intake stroke is taken as the first target air pressure value, and the minimum air pressure value of the second load sensor in the intake stroke is taken as the second target air pressure value. Determine the pressure deviation between the first target air pressure value and the second target air pressure value; Using the first target air pressure value as the reference air pressure value, the reference air pressure value is compensated and corrected according to the air pressure deviation to obtain the intake pressure of the cylinder.

[0007] On the other hand, for any cylinder, after taking the minimum air pressure value of the first load sensor during the intake stroke as the first target air pressure value and the minimum air pressure value of the second load sensor during the intake stroke as the second target air pressure value, and before determining the intake pressure of the cylinder based on the first target air pressure value and the second target air pressure value through a preset third correspondence, the fuel control method for the multi-cylinder engine further includes: Determine whether the first target air pressure value and the second target air pressure value exceed the corresponding physical limit; If either the first target air pressure value or the second target air pressure value exceeds the corresponding physical limit, then the one of the first target air pressure value and the second target air pressure value that does not exceed the corresponding physical limit shall be used as the intake pressure of the cylinder.

[0008] On the other hand, after determining whether the first target air pressure value and the second target air pressure value exceed the corresponding physical limits, the fuel control method for the multi-cylinder engine further includes: If both the first target air pressure value and the second target air pressure value exceed the corresponding physical limit, then the preset fault state replacement value will be used as the intake pressure of the cylinder.

[0009] On the other hand, identifying the intake stroke of each cylinder in a multi-cylinder engine includes: After power-on, based on the first air pressure value of the first load sensor, the first correspondence between the crankshaft angle of the multi-cylinder engine and the intake stroke of each cylinder is determined. Based on the first correspondence and the real-time crankshaft angle of the multi-cylinder engine, the intake stroke of each cylinder is identified.

[0010] On the other hand, the process of determining the first correspondence between the crankshaft angle of the multi-cylinder engine and the intake stroke of each cylinder based on the first air pressure value of the first load sensor after power-on includes: After power-on, the first air pressure value of the first load sensor is determined to correspond to the target air pressure value range of the intake stroke in the second correspondence relationship; the second correspondence relationship is the correspondence between intake pressure and stroke. The angle range of crankshaft rotation when the first air pressure value is within the target air pressure value range is determined as the angle range corresponding to the intake stroke of the specified cylinder. Based on the angle range corresponding to the intake stroke of the specified cylinder and the working sequence of each cylinder, the angle range corresponding to the intake stroke of the remaining cylinders is determined. The angle range corresponding to the intake stroke of each cylinder is taken as the first correspondence between the crankshaft angle of a multi-cylinder engine and the intake stroke of each cylinder.

[0011] On the other hand, identifying the intake stroke of each cylinder in a multi-cylinder engine includes: Under steady-state conditions, identify the intake stroke of each cylinder in a multi-cylinder engine; The fuel control method for the multi-cylinder engine also includes: Under transitional operating conditions, the intake volume corresponding to the current speed and throttle opening is determined according to the fourth correspondence, and used as the intake volume of each cylinder. The fourth correspondence is the relationship between the engine speed of a multi-cylinder engine and the throttle opening and intake air volume.

[0012] On the other hand, if either the first target air pressure value or the second target air pressure value exceeds the corresponding physical limit, then the one of the first target air pressure value and the second target air pressure value that does not exceed the corresponding physical limit is taken as the intake air pressure of the cylinder. The fuel control method for the multi-cylinder engine further includes: For any cylinder, when the cylinder is in the intake stroke, the minimum air pressure value of the second load sensor in the intake stroke is taken as the second target air pressure value. Record the throttle opening and engine speed of the multi-cylinder engine at the moment of acquisition of the second target air pressure value; The fourth correspondence is constructed based on the throttle opening and speed of the multi-cylinder engine at the time of acquisition of the second target air pressure value, and the intake air volume corresponding to the second target air pressure value.

[0013] To address the aforementioned technical problems, the present invention also provides a fuel control device for a multi-cylinder engine, comprising: Memory, used to store computer programs; A processor is used to execute the computer program to implement the steps of the fuel control method for a multi-cylinder engine as described above.

[0014] To address the aforementioned technical problems, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the fuel control method for a multi-cylinder engine as described above.

[0015] Beneficial Effects: This invention provides a fuel control method for a multi-cylinder engine. Considering that a multi-cylinder engine can accommodate two load sensors, if the pressure crosstalk between the intake branches of each cylinder is isolated by a one-way valve, the measurement accuracy of the second load sensor located in the main intake pipe can be improved. This invention sets a first load sensor in the intake branch of a single designated cylinder and a second load sensor in the main intake pipe of each cylinder. When any cylinder is in the intake stroke, the first pressure value of the first load sensor and the second pressure value of the second load sensor can be combined to determine the intake pressure of that cylinder. Then, based on the intake volume corresponding to the intake pressure, the target fuel injection quantity of that cylinder can be determined and the fuel injection quantity can be controlled. Since the intake pressure of a single cylinder can be determined by combining the pressure values ​​of two load sensors at different locations, and the design of the one-way valve improves the detection accuracy of the second load sensor, this invention can accurately determine the intake pressure and corresponding intake volume of each cylinder in a multi-cylinder engine and perform fuel control. Therefore, it is beneficial for the air-fuel ratio of each cylinder to reach the theoretical optimal range, thereby optimizing the engine's emission performance and fuel economy.

[0016] The present invention also provides a fuel control device and a computer-readable storage medium for a multi-cylinder engine, which have the same beneficial effects as the fuel control method for the multi-cylinder engine described above. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the relevant technologies and the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic flowchart of a fuel control method for a multi-cylinder engine provided by the present invention; Figure 2 A schematic diagram of the structure of a fuel control system for a multi-cylinder engine provided by the present invention; Figure 3 A cylinder pressure waveform diagram of a multi-cylinder engine provided by the present invention; Figure 4This is a schematic diagram of the structure of a fuel control device for a multi-cylinder engine provided by the present invention. Detailed Implementation

[0019] The core of this invention is to provide a fuel control method, device, and computer-readable storage medium for a multi-cylinder engine. This invention sets up a first load sensor in the intake branch of a single designated cylinder and a second load sensor in the main intake pipe of all cylinders. When any cylinder is in its intake stroke, the first pressure value from the first load sensor and the second pressure value from the second load sensor can be combined to determine the intake pressure of that cylinder. Then, based on the intake volume corresponding to that intake pressure, the target fuel injection quantity for that cylinder is determined and fuel injection quantity control is performed. Because the intake pressure of a single cylinder can be determined by combining the pressure values ​​from two load sensors at different locations, and the design of the one-way valve improves the detection accuracy of the second load sensor, this invention can accurately determine the intake pressure and corresponding intake volume of each cylinder in a multi-cylinder engine and perform fuel control. This helps to achieve the theoretically optimal air-fuel ratio for each cylinder, thereby optimizing the engine's emission performance and fuel economy.

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please refer to Figure 1 , Figure 1 This is a flowchart illustrating a fuel control method for a multi-cylinder engine provided by the present invention. The fuel control method for the multi-cylinder engine includes: S101: Identify the intake stroke of each cylinder in a multi-cylinder engine; Specifically, considering the technical problems mentioned above, the actual intake volume of each cylinder in a multi-cylinder engine deviates due to manufacturing tolerances and differences in the dynamic characteristics of the combustion system. Furthermore, considering that a multi-cylinder engine can accommodate two load sensors, isolating the pressure crosstalk between the intake branches of each cylinder using a one-way valve can improve the measurement accuracy of the second load sensor located in the main intake pipe. Therefore, this embodiment of the invention aims to determine the cylinder's intake pressure based on the first pressure value of the first load sensor and the second pressure value of the second load sensor, and then determine the target fuel injection quantity of the cylinder based on the intake volume corresponding to the cylinder's intake pressure. The first load sensor can be located in the intake branch of a single designated cylinder in the multi-cylinder engine to measure the pressure value of that single designated cylinder, while the second load sensor can be located in the main intake pipe of all cylinders in the multi-cylinder engine to measure the pressure value of each cylinder sequentially.

[0022] Specifically, considering that the amount of fuel injected into a cylinder in fuel control needs to be determined by the amount of air intake in the cylinder, and the amount of air intake in a cylinder depends on the minimum air pressure value of that cylinder during the intake stroke, in order to determine the amount of fuel injected into a cylinder in this step, the intake stroke of each cylinder in a multi-cylinder engine can be identified first, so as to use it as the data basis for subsequent steps.

[0023] S102: For any cylinder, when the cylinder is in the intake stroke, the intake pressure of the cylinder is determined according to the first pressure value of the first load sensor and the second pressure value of the second load sensor. The first load sensor is installed in the intake branch of a single designated cylinder in the multi-cylinder engine, and the second load sensor is installed in the main intake pipe of each cylinder in the multi-cylinder engine. Each cylinder's intake branch is equipped with a one-way valve that leads from the main intake pipe to the cylinder. Specifically, when any cylinder is in the intake stroke, its intake pressure can be determined. The core of this invention is to determine the cylinder's intake pressure based on the first pressure value of the first load sensor and the second pressure value of the second load sensor. Since the pressure values ​​of the two load sensors can be combined and mutually corrected and compensated, the accuracy of the determined cylinder's intake pressure can be improved, which is beneficial to improving the accuracy of the final target fuel injection quantity.

[0024] S103: Determine the target fuel injection quantity of the cylinder based on the intake volume corresponding to the intake pressure of the cylinder, so as to control the fuel injection quantity.

[0025] Specifically, after determining the cylinder's intake pressure, the target fuel injection quantity of the cylinder can be determined based on the intake volume corresponding to the cylinder's intake pressure, so as to control the fuel injection quantity. The intake volume can be determined using the ideal gas equation: PV=mRT, where P is the intake pressure, V is the volume at the intake manifold of the cylinder, R is a constant, m is the intake volume in the intake manifold of the cylinder, and T is the intake temperature.

[0026] The number of cylinders in a multi-cylinder engine can be varied, and the application scenarios of a multi-cylinder engine can be arbitrary. This embodiment of the invention does not limit the specific application scenarios.

[0027] Specifically, for a better explanation of the embodiments of the present invention, please refer to... Figure 2 , Figure 2 This is a schematic diagram of the structure of a fuel control system for a multi-cylinder engine provided by the present invention. Figure 2 The multi-cylinder engine in the middle includes four cylinders, Figure 2 Both the first and second load sensors are mounted on the engine's throttle body. The first load sensor is located on the intake manifold of cylinder 1 within the throttle body, while the second load sensor is located at the main intake manifold of the four cylinder intake branches. During actual calibration testing, it was found that when the second load sensor collects the pressure signal of a certain cylinder, because it is a four-cylinder engine with a 180° interval between the intake timings of each cylinder, and the angle from ambient pressure to the pressure representing the intake volume and back to ambient pressure exceeds 180° (generally between 200-360°), it is easily interfered with by the pressure signals of other cylinders, resulting in cylinder pressure distortion and an inability to effectively correct the intake pressure of that cylinder. Therefore, in this embodiment of the invention, a one-way valve is provided in the intake branch of each cylinder, which leads from the main intake pipe to the cylinder. In this way, the air pressure value of each cylinder collected by the second load sensor is not affected by the air pressure of other cylinders. That is, the air pressure value of the second load sensor only represents the intake pressure of the single cylinder being detected; thereby improving the signal confidence of the second load pressure sensor.

[0028] This invention provides a fuel control method for a multi-cylinder engine. Considering that a multi-cylinder engine can accommodate two load sensors, the measurement accuracy of the second load sensor located in the main intake manifold can be improved by isolating the air pressure crosstalk between the intake branches of each cylinder through a one-way valve. This invention sets a first load sensor in the intake branch of a single designated cylinder and a second load sensor in the main intake manifold of each cylinder. When any cylinder is in the intake stroke, the first air pressure value of the first load sensor and the second air pressure value of the second load sensor can be combined to determine the intake pressure of that cylinder. Then, based on the intake volume corresponding to the intake pressure, the target fuel injection quantity of that cylinder can be determined and the fuel injection quantity can be controlled. Since the intake pressure of a single cylinder can be determined by combining the air pressure values ​​of two load sensors at different locations, and the design of the one-way valve improves the detection accuracy of the second load sensor, this invention can accurately determine the intake pressure and corresponding intake volume of each cylinder in a multi-cylinder engine and perform fuel control. Therefore, it is beneficial for the air-fuel ratio of each cylinder to reach the theoretical optimal range, thereby optimizing the engine's emission performance and fuel economy.

[0029] Based on the above embodiments: As an optional embodiment, for any cylinder, when the cylinder is in the intake stroke, determining the cylinder's intake pressure based on the first pressure value of the first load sensor and the second pressure value of the second load sensor includes: For any cylinder, when the cylinder is in the intake stroke, the minimum air pressure value of the first load sensor in the intake stroke is taken as the first target air pressure value, and the minimum air pressure value of the second load sensor in the intake stroke is taken as the second target air pressure value. Determine the pressure deviation between the first target air pressure value and the second target air pressure value; Using the first target air pressure value as the reference air pressure value, the reference air pressure value is compensated and corrected according to the air pressure deviation to obtain the cylinder intake pressure.

[0030] Specifically, considering that for any given cylinder, the first load sensor can more accurately reflect the intake pressure of a single cylinder, while the second load sensor can be used as a reference to compensate for the pressure value of the first load sensor, in this embodiment of the invention, for any given cylinder, when the cylinder is in the intake stroke, the minimum pressure value of the first load sensor during the intake stroke is taken as the first target pressure value, and the minimum pressure value of the second load sensor during the intake stroke is taken as the second target pressure value; and the first target pressure value is used as the reference pressure value, and the reference pressure value is compensated and corrected according to the pressure deviation to obtain the intake pressure of the cylinder; the calculation process is relatively simple and quick, and the obtained intake pressure has high accuracy.

[0031] Alternatively, as an optional embodiment, using a first target air pressure value as a reference air pressure value, and compensating and correcting the reference air pressure value according to the air pressure deviation, the intake pressure of the cylinder is obtained including: Based on the first target air pressure value and the second target air pressure value, the intake pressure of the cylinder is determined through a preset third correspondence. The third correspondence includes: P j =P1+(P1-P2)×fac / 2; Among them, P j P1 is the intake pressure of the cylinder, P2 is the first target air pressure value, P2 is the second target air pressure value, and fac is the preset correction coefficient.

[0032] Specifically, for any cylinder, the minimum air pressure value during the intake stroke can be used as the intake pressure of that cylinder. Therefore, in this embodiment of the invention, for any cylinder, when the cylinder is in the intake stroke, the minimum air pressure value of the first load sensor during the intake stroke is used as the first target air pressure value, and the minimum air pressure value of the second load sensor during the intake stroke is used as the second target air pressure value. Then, based on the first target air pressure value and the second target air pressure value, the intake pressure of the cylinder is determined through a preset third correspondence relationship.

[0033] The third correspondence can use the intake pressure of a specified single cylinder determined by the first load sensor as a reference. The reference is corrected by the calculation result of the difference between the first target air pressure value and the second target air pressure value and the correction coefficient, and finally the intake pressure of the cylinder is obtained, which can improve the measurement accuracy of the cylinder intake pressure.

[0034] Of course, in addition to this specific form, the third correspondence can also take other specific forms, which are not limited in this embodiment of the invention.

[0035] Among them, you can refer to Figure 3 , Figure 3 The present invention provides a cylinder pressure waveform diagram of a multi-cylinder engine. The waveform shown in the figure is the pressure waveform of a certain cylinder in a certain cycle. The time interval T1 and T2 corresponds to the intake stroke of the corresponding cylinder, and the minimum pressure value (that is, the pressure value at time T3) can be used as the intake pressure of the cylinder.

[0036] As an optional embodiment, for any cylinder, when the cylinder is in the intake stroke, after taking the minimum air pressure value of the first load sensor during the intake stroke as the first target air pressure value and the minimum air pressure value of the second load sensor during the intake stroke as the second target air pressure value, and before determining the cylinder's intake pressure based on the first target air pressure value and the second target air pressure value through a preset third correspondence, the fuel control method for a multi-cylinder engine further includes: Determine whether the first target air pressure value and the second target air pressure value exceed the corresponding physical limit; If either the first target air pressure value or the second target air pressure value exceeds the corresponding physical limit, then the one of the first target air pressure value and the second target air pressure value that does not exceed the corresponding physical limit shall be used as the intake air pressure of the cylinder.

[0037] Specifically, considering the possibility of malfunctions in both the first and second load sensors, in order to avoid the impact of malfunctions on the accuracy of intake pressure measurement, this embodiment of the invention sets corresponding physical limits for the first and second target air pressure values, and can determine whether the first and second target air pressure values ​​exceed the corresponding physical limits. If one of them exceeds the corresponding physical limit, the one that does not exceed the corresponding physical limit can be used as the intake pressure of the cylinder, thereby avoiding the impact of malfunctions on the accuracy of intake pressure measurement. For example, when the first target air pressure value exceeds the corresponding physical limit, the second target air pressure value can be used as the intake pressure of the cylinder.

[0038] As an optional embodiment, after determining whether the first target air pressure value and the second target air pressure value exceed the corresponding physical limit, the fuel control method for a multi-cylinder engine further includes: If both the first target air pressure value and the second target air pressure value exceed the corresponding physical limit, the preset fault state replacement value will be used as the cylinder intake pressure.

[0039] Specifically, considering the possibility that both load sensors may simultaneously exceed their corresponding physical limits, in order to reliably control fuel in such cases, this embodiment of the invention can identify such cases and use a preset fault state substitution value as the cylinder intake pressure. The preset fault state substitution value can be used as the cylinder intake pressure within a certain accuracy range so that the engine can continue to operate uninterruptedly.

[0040] The fault state replacement value can be set flexibly and autonomously based on experience and historical data, and this embodiment of the invention does not limit it.

[0041] As an optional embodiment, identifying the intake stroke of each cylinder in a multi-cylinder engine includes: After power-on, based on the first air pressure value of the first load sensor, the first correspondence between the crankshaft angle of the multi-cylinder engine and the intake stroke of each cylinder is determined. Based on the first correspondence and the real-time crankshaft angle of the multi-cylinder engine, the intake stroke of each cylinder is identified.

[0042] Specifically, considering that the first correspondence between the crankshaft angle of the multi-cylinder engine and the intake stroke of each cylinder can be used to efficiently and accurately identify the intake stroke of each cylinder, in this embodiment of the invention, after power-on, the first correspondence between the crankshaft angle of the multi-cylinder engine and the intake stroke of each cylinder can be determined according to the first air pressure value of the first load sensor. Then, based on the first correspondence and the real-time crankshaft angle of the multi-cylinder engine, the intake stroke of each cylinder can be identified.

[0043] As an optional embodiment, after power-on, determining the first correspondence between the crankshaft angle of the multi-cylinder engine and the intake stroke of each cylinder based on the first air pressure value of the first load sensor includes: After power-on, the first air pressure value of the first load sensor is determined to correspond to the target air pressure value range of the intake stroke in the second correspondence relationship; the second correspondence relationship is the correspondence between intake pressure and stroke. The angle range of crankshaft rotation when the first air pressure value is within the target air pressure value range is determined as the angle range corresponding to the intake stroke of the specified cylinder. Based on the angle range corresponding to the intake stroke of the specified cylinder and the working sequence of each cylinder, determine the angle range corresponding to the intake stroke of the remaining cylinders. The angle range corresponding to the intake stroke of each cylinder is taken as the first correspondence between the crankshaft angle of a multi-cylinder engine and the intake stroke of each cylinder.

[0044] For details, please refer to Figure 3 It can be seen that the target air pressure range of the first air pressure value of the first load sensor corresponding to the second correspondence stroke can be determined by the correspondence between intake pressure and stroke. Figure 3 The T1 to T2 interval is defined, and the crankshaft angle interval when the first air pressure value is within the target air pressure value interval is defined as the angle interval corresponding to the intake stroke of the specified cylinder. After having the angle interval corresponding to the intake stroke of a single specified cylinder, the angle interval corresponding to the intake stroke of the remaining cylinders can be determined according to the angle interval corresponding to the intake stroke of the specified cylinder and the working sequence of each cylinder. Finally, the angle interval corresponding to the intake stroke of each cylinder can be used as the first correspondence between the crankshaft angle of the multi-cylinder engine and the intake stroke of each cylinder.

[0045] Of course, in addition to this specific form, "after power-on, the first correspondence between the crankshaft angle of the multi-cylinder engine and the intake stroke of each cylinder is determined based on the first air pressure value of the first load sensor" can also be in other forms, and the embodiments of the present invention are not limited here.

[0046] As an optional embodiment, identifying the intake stroke of each cylinder in a multi-cylinder engine includes: Under steady-state conditions, identify the intake stroke of each cylinder in a multi-cylinder engine; Fuel control methods for multi-cylinder engines also include: Under transitional operating conditions, the intake volume corresponding to the current speed and throttle opening is determined according to the fourth correspondence, and used as the intake volume of each cylinder. The fourth correspondence is the relationship between the engine speed of a multi-cylinder engine and the throttle opening and intake volume.

[0047] Specifically, considering that the accuracy of identifying the intake volume by throttle opening is higher under transitional operating conditions, the steps mentioned above to identify the intake stroke of each cylinder in a multi-cylinder engine and determine the intake volume can be performed under steady-state conditions. However, for transitional operating conditions, the intake volume corresponding to the current speed and throttle opening can be determined according to the fourth correspondence, which can be used as the intake volume of each cylinder, thereby improving the accuracy of intake volume identification under transitional operating conditions.

[0048] As an optional embodiment, if either the first target air pressure value or the second target air pressure value exceeds the corresponding physical limit, then the one of the first target air pressure value and the second target air pressure value that does not exceed the corresponding physical limit is taken as the intake air pressure of the cylinder. The fuel control method for a multi-cylinder engine further includes: For any cylinder, when the cylinder is in the intake stroke, the minimum air pressure value of the second load sensor in the intake stroke is taken as the second target air pressure value. Record the throttle opening and engine speed of the multi-cylinder engine at the moment of acquisition of the second target air pressure value; Based on the recorded throttle opening and speed of the multi-cylinder engine at the time of acquisition of the second target air pressure value, and the intake volume corresponding to the second target air pressure value, a fourth correspondence is constructed.

[0049] Specifically, considering that under steady-state conditions, the fourth correspondence can be accurately determined by recording the throttle opening and speed at the time of collecting the second target air pressure value, this embodiment of the invention can record the throttle opening and speed of the multi-cylinder engine at the time of collecting the second target air pressure value, and construct the fourth correspondence based on the recorded throttle opening and speed of the multi-cylinder engine at the time of collecting the second target air pressure value, as well as the intake volume corresponding to the second target air pressure value, so as to use it as the data basis for intake volume identification under transitional conditions, which is beneficial to improving the accuracy of intake volume identification under transitional conditions.

[0050] Of course, in addition to these, there are many other ways to determine the fourth correspondence, and the embodiments of the present invention are not limited here.

[0051] Please refer to Figure 4 , Figure 4This invention provides a structural schematic diagram of a fuel control device for a multi-cylinder engine, which includes: Memory 41 is used to store computer programs; The processor 42 is used to execute a computer program to implement the steps of the fuel control method for a multi-cylinder engine as described in the foregoing embodiments.

[0052] For a description of the fuel control device for a multi-cylinder engine provided in this embodiment of the invention, please refer to the aforementioned embodiment of the fuel control method for a multi-cylinder engine. This embodiment of the invention will not be repeated here.

[0053] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the fuel control method for a multi-cylinder engine as described in the foregoing embodiments.

[0054] For a description of the computer-readable storage medium provided in the embodiments of the present invention, please refer to the aforementioned embodiments of the fuel control method for a multi-cylinder engine; the embodiments of the present invention will not be repeated here.

[0055] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. It should also be noted that in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0056] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fuel control method for a multi-cylinder engine, characterized in that, include: Identify the intake stroke of each cylinder in a multi-cylinder engine; For any cylinder, when the cylinder is in the intake stroke, the intake pressure of the cylinder is determined according to the first pressure value of the first load sensor and the second pressure value of the second load sensor. The first load sensor is installed in the intake branch of a single designated cylinder in the multi-cylinder engine, and the second load sensor is installed in the main intake pipe of each cylinder in the multi-cylinder engine. Each cylinder's intake branch is equipped with a one-way valve that leads from the main intake pipe to the cylinder. The target fuel injection quantity of the cylinder is determined based on the intake air volume corresponding to the intake pressure of the cylinder, so as to control the fuel injection quantity.

2. The fuel control method for a multi-cylinder engine according to claim 1, characterized in that, For any cylinder, when the cylinder is in the intake stroke, determining the intake pressure of the cylinder based on the first pressure value of the first load sensor and the second pressure value of the second load sensor includes: For any cylinder, when the cylinder is in the intake stroke, the minimum air pressure value of the first load sensor in the intake stroke is taken as the first target air pressure value, and the minimum air pressure value of the second load sensor in the intake stroke is taken as the second target air pressure value. Determine the pressure deviation between the first target air pressure value and the second target air pressure value; Using the first target air pressure value as the reference air pressure value, the reference air pressure value is compensated and corrected according to the air pressure deviation to obtain the intake pressure of the cylinder.

3. The fuel control method for a multi-cylinder engine according to claim 2, characterized in that, For any cylinder, when the cylinder is in the intake stroke, after taking the minimum air pressure value of the first load sensor during the intake stroke as the first target air pressure value and the minimum air pressure value of the second load sensor during the intake stroke as the second target air pressure value, before determining the intake pressure of the cylinder based on the first target air pressure value and the second target air pressure value through a preset third correspondence, the fuel control method for the multi-cylinder engine further includes: Determine whether the first target air pressure value and the second target air pressure value exceed the corresponding physical limit; If either the first target air pressure value or the second target air pressure value exceeds the corresponding physical limit, then the one of the first target air pressure value and the second target air pressure value that does not exceed the corresponding physical limit shall be used as the intake pressure of the cylinder.

4. The fuel control method for a multi-cylinder engine according to claim 3, characterized in that, After determining whether the first target air pressure value and the second target air pressure value exceed the corresponding physical limits, the fuel control method for the multi-cylinder engine further includes: If both the first target air pressure value and the second target air pressure value exceed the corresponding physical limit, then the preset fault state replacement value will be used as the intake pressure of the cylinder.

5. The fuel control method for a multi-cylinder engine according to claim 1, characterized in that, The identification of the intake stroke of each cylinder in a multi-cylinder engine includes: After power-on, based on the first air pressure value of the first load sensor, the first correspondence between the crankshaft angle of the multi-cylinder engine and the intake stroke of each cylinder is determined. Based on the first correspondence and the real-time crankshaft angle of the multi-cylinder engine, the intake stroke of each cylinder is identified.

6. The fuel control method for a multi-cylinder engine according to claim 5, characterized in that, The step of determining the first correspondence between the crankshaft angle of the multi-cylinder engine and the intake stroke of each cylinder based on the first air pressure value of the first load sensor after power-on includes: After power-on, the first air pressure value of the first load sensor is determined to correspond to the target air pressure value range of the intake stroke in the second correspondence relationship; the second correspondence relationship is the correspondence between intake pressure and stroke. The angle range of crankshaft rotation when the first air pressure value is within the target air pressure value range is determined as the angle range corresponding to the intake stroke of the specified cylinder. Based on the angle range corresponding to the intake stroke of the specified cylinder and the working sequence of each cylinder, the angle range corresponding to the intake stroke of the remaining cylinders is determined. The angle range corresponding to the intake stroke of each cylinder is taken as the first correspondence between the crankshaft angle of a multi-cylinder engine and the intake stroke of each cylinder.

7. The fuel control method for a multi-cylinder engine according to any one of claims 1 to 6, characterized in that, The identification of the intake stroke of each cylinder in a multi-cylinder engine includes: Under steady-state conditions, identify the intake stroke of each cylinder in a multi-cylinder engine; The fuel control method for the multi-cylinder engine also includes: Under transitional operating conditions, the intake volume corresponding to the current speed and throttle opening is determined according to the fourth correspondence, and used as the intake volume of each cylinder. The fourth correspondence is the relationship between the engine speed of a multi-cylinder engine and the throttle opening and intake air volume.

8. The fuel control method for a multi-cylinder engine according to claim 7, characterized in that, If either the first target air pressure value or the second target air pressure value exceeds the corresponding physical limit, then the one of the first target air pressure value and the second target air pressure value that does not exceed the corresponding physical limit is taken as the intake air pressure of the cylinder. The fuel control method for the multi-cylinder engine further includes: For any cylinder, when the cylinder is in the intake stroke, the minimum air pressure value of the second load sensor in the intake stroke is taken as the second target air pressure value. Record the throttle opening and engine speed of the multi-cylinder engine at the moment of acquisition of the second target air pressure value; The fourth correspondence is constructed based on the throttle opening and speed of the multi-cylinder engine at the time of acquisition of the second target air pressure value, and the intake air volume corresponding to the second target air pressure value.

9. A fuel control device for a multi-cylinder engine, characterized in that, include: Memory, used to store computer programs; A processor for executing the computer program to implement the steps of the fuel control method for a multi-cylinder engine as claimed in any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the fuel control method for a multi-cylinder engine as described in any one of claims 1 to 8.

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