Method and system for determining engine air-fuel ratio transmission delay

Abstract

The method and system for determining the engine air-fuel ratio transmission delay provided by the present invention is to determine the engine air-fuel ratio steady-state theoretical transmission delay by obtaining the first time from the fuel supply instruction to the exhaust valve opening, the local time for the exhaust gas to be transmitted to the air-fuel ratio sensor, and the third time of the steady-state theoretical response of the air-fuel ratio sensor; determine the transient response time correction amount according to the air-fuel ratio state change learning value and the engine air-fuel ratio steady-state theoretical transmission delay; and determine the engine air-fuel ratio transient transmission delay in combination with the engine air-fuel ratio steady-state theoretical transmission delay. Compared with the prior art, this case takes into account the engine air-fuel ratio transmission delay, confirms the transient response time correction amount according to the air-fuel ratio state change learning value, and after adding the correction process, determines the engine air-fuel ratio transient transmission delay more accurately and efficiently.

Description

Technical Field

[0001] The present invention relates to the technical field of engine detection, and in particular to a method and system for determining engine air-fuel ratio transmission delay. Background Art

[0002] During the operation of the engine, the ratio of air flow to fuel flow is called the air-fuel ratio: the air-fuel ratio is one of the important indicators reflecting the emission, power and economy of the engine vehicle. Accurate control of the air-fuel ratio can effectively improve the power and economy of the engine and reduce the emission of harmful pollutants.

[0003] During the operation of the automobile engine, when one or more of a series of parameters such as speed, output torque and internal heat balance of the engine change with time, this operating condition is called transient operating condition, that is, the engine is not stable. About 40%-80% of harmful emissions and fuel consumption are generated under transient engine conditions. Usually, an air-fuel ratio sensor installed in the exhaust pipe is used to measure the exhaust gas to obtain the air-fuel ratio of the mixture. Since the position for measuring the air-fuel ratio is in the exhaust pipe, the signal output by the air-fuel ratio sensor only reflects the concentration of the mixed gas after combustion. Therefore, the change in the air-fuel ratio of the mixture caused by the change in fuel injection amount or air amount cannot be immediately sensed by the air-fuel ratio sensor, but there is a transmission delay. The transmission delay determines the dynamics of the air-fuel ratio closed-loop control, which is determined by the engine speed, load, installation position of the air-fuel ratio sensor and the response characteristics of the air-fuel ratio sensor itself. Under transient conditions, in order to reduce emissions and fuel consumption, the air-fuel ratio control deviation needs to be corrected quickly and accurately, requiring the air-fuel ratio control system to have a faster response speed and higher control accuracy. Accurate calculation of the air-fuel ratio transmission delay is one of the key links.

[0004] Therefore, it is an urgent problem to be solved by those skilled in the art to provide a method and system for determining engine air-fuel ratio transmission delay to solve the above-mentioned problem. Summary of the invention

[0005] The object of the present invention is to provide a method for determining the transmission delay of the air-fuel ratio of an engine, which has clear logic, is safe, effective, reliable and easy to operate, and can effectively improve the response speed and control accuracy of the air-fuel ratio control.

[0006] Based on the above objectives, the technical solution provided by the present invention is as follows:

[0007] A method for determining engine air-fuel ratio transmission delay comprises the following steps:

[0008] determining a steady-state theoretical transmission delay of the engine air-fuel ratio based on a first time from a fuel supply command to exhaust valve opening, a second time for exhaust gas to be transmitted to an air-fuel ratio sensor, and a third time for a steady-state theoretical response of the air-fuel ratio sensor;

[0009] Determining a transient response time correction amount according to the steady-state theoretical transmission delay of the engine air-fuel ratio and a learning value of the air-fuel ratio state change;

[0010] The engine air-fuel ratio transient transmission delay is determined according to the steady-state theoretical transmission delay and the transient response time correction amount.

[0011] Preferably, obtaining the fuel supply instruction to the first time of exhaust valve opening includes the following steps:

[0012] Obtaining the crankshaft angle when the engine exhaust valve is opened, the crankshaft angle when fuel is supplied, and the engine speed;

[0013] According to the crankshaft angle when the exhaust valve of the engine is opened, the crankshaft angle when the fuel is supplied, and the engine speed, obtaining the first time from the fuel supply instruction to the exhaust valve opening;

[0014] The formula for obtaining the first time from the fuel supply instruction to the exhaust valve opening is specifically:

[0015] ;

[0016] in, The first time from the fuel supply command to the exhaust valve opening, is the crankshaft angle when the exhaust valve opens, is the crankshaft angle at the time of fuel supply, is the engine speed.

[0017] Preferably, the step of obtaining the second time when the exhaust gas is transmitted to the air-fuel ratio sensor comprises the following steps:

[0018] Obtain exhaust pipe volume and exhaust gas volume flow rate;

[0019] acquiring a second time for the exhaust gas to be transmitted to the air-fuel ratio sensor according to the exhaust pipe volume and the exhaust gas volume flow rate;

[0020] The formula for obtaining the second time for the exhaust gas to be transmitted to the air-fuel ratio sensor is specifically:

[0021] ;

[0022] in, The second time that the exhaust gas is transmitted to the air-fuel ratio sensor. is the exhaust pipe volume, is the exhaust gas volume flow rate.

[0023] Preferably, obtaining the exhaust gas volume flow rate comprises the following steps:

[0024] Obtain exhaust pipe temperature, exhaust pipe pressure and exhaust gas mass flow rate;

[0025] Obtaining the exhaust gas volume flow rate according to the exhaust pipe temperature, the exhaust pipe pressure, the exhaust gas mass flow rate and the ideal gas constant;

[0026] The formula for obtaining the exhaust gas volume flow rate is specifically:

[0027] ;

[0028] in, is the exhaust gas volume flow rate, is the ideal gas constant, is the exhaust pipe temperature, is the exhaust pipe pressure, is the exhaust gas mass flow rate.

[0029] Preferably, the formula for the third time of the steady-state theoretical response of the air-fuel ratio sensor is specifically:

[0030] ;

[0031] in, The third time of the steady-state theoretical response of the air-fuel ratio sensor, is the exhaust gas mass flow rate, is the exhaust pipe temperature.

[0032] Preferably, the formula for determining the steady-state theoretical transmission delay of the engine air-fuel ratio is specifically:

[0033] ;

[0034] in, is the theoretical transmission delay of the steady-state air-fuel ratio of the engine, The first time from the fuel supply command to the exhaust valve opening, The second time that the exhaust gas is transmitted to the air-fuel ratio sensor. It is the third time of the steady-state theoretical response of the air-fuel ratio sensor.

[0035] Preferably, determining the transient response time correction amount according to the steady-state theoretical transmission delay of the engine air-fuel ratio and the air-fuel ratio state change learning value comprises the following steps:

[0036] Control the fuel supply to increase or decrease to obtain different air-fuel ratio state change curves;

[0037] taking the deviation between the air-fuel ratio change time period and the steady-state transmission delay as the air-fuel ratio state change learning value;

[0038] The corresponding air-fuel ratio state change learning value is selected according to the current air-fuel ratio state to obtain the transient response time correction amount.

[0039] Preferably, determining the transient transmission delay of the engine air-fuel ratio according to the steady-state theoretical transmission delay and the transient response time correction amount comprises the following steps:

[0040] Integrating and solving the sum of the steady-state theoretical transmission delay and the transient response time correction amount to obtain the transient transmission delay of the engine air-fuel ratio;

[0041] The formula for obtaining the transient transmission delay of the engine air-fuel ratio is as follows:

[0042] ;

[0043] ;

[0044] in, is the transient transmission delay of the engine air-fuel ratio, is the theoretical transmission delay of the steady-state engine air-fuel ratio, is the transient response time correction.

[0045] A system for determining engine air-fuel ratio transmission delay, comprising:

[0046] a steady-state theoretical transmission delay module, for determining a steady-state theoretical transmission delay of an engine air-fuel ratio according to a first time from a fuel supply command to an exhaust valve opening, a second time from exhaust gas transmission to an air-fuel ratio sensor, and a third time of a steady-state theoretical response of the air-fuel ratio sensor;

[0047] A transient response time correction module, used to determine a transient response time correction according to a steady-state theoretical transmission delay of the engine air-fuel ratio and a learning value of an air-fuel ratio state change;

[0048] The transient transmission delay module is used to determine the transient transmission delay of the engine air-fuel ratio according to the steady-state theoretical transmission delay and the transient response time correction amount.

[0049] The method for determining the engine air-fuel ratio transmission delay provided by the present invention is to determine the steady-state theoretical transmission delay of the engine air-fuel ratio by obtaining the first time from the fuel supply instruction to the exhaust valve opening, the local time for the exhaust gas to be transmitted to the air-fuel ratio sensor, and the third time of the steady-state theoretical response of the air-fuel ratio sensor; determine the transient response time correction amount according to the air-fuel ratio state change learning value and the steady-state theoretical transmission delay; and determine the transient transmission delay of the engine air-fuel ratio in combination with the steady-state theoretical transmission delay.

[0050] Compared with the prior art, this case takes transmission delay into consideration and confirms the transient response time correction amount according to the air-fuel ratio state change learning value. After adding the correction process, the transient transmission delay of the engine air-fuel ratio can be determined more accurately and efficiently.

[0051] The present invention also provides an engine air-fuel ratio transmission delay determination system, which has the same technical concept as the method, solves the same technical problem, and should have the same beneficial effects, so it will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] 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, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0053] Figure 1 A flow chart of a method for determining engine air-fuel ratio transmission delay provided by an embodiment of the present invention;

[0054] Figure 2 A flow chart of obtaining a fuel supply instruction to the first time of exhaust valve opening provided by an embodiment of the present invention;

[0055] Figure 3 A flow chart for obtaining a second time for exhaust gas to be transmitted to an air-fuel ratio sensor provided by an embodiment of the present invention;

[0056] Figure 4 A flow chart for obtaining the exhaust gas volume flow provided by an embodiment of the present invention;

[0057] Figure 5 A flowchart of step S2 provided in an embodiment of the present invention;

[0058] Figure 6 A schematic diagram of the structure of a system for determining an engine air-fuel ratio transmission delay provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0059] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] The embodiments of the present invention are written in a progressive manner.

[0061] The embodiment of the present invention provides a method and system for determining transmission delay of an engine air-fuel ratio, which mainly solves the technical problem in the prior art that an air-fuel ratio control system is affected by transmission delay, resulting in slow response speed and low control accuracy.

[0062] like Figure 1 As shown, a method for determining engine air-fuel ratio transmission delay comprises the following steps:

[0063] S1. Determine the engine air-fuel ratio steady-state theoretical transmission delay according to the first time from the fuel supply command to the exhaust valve opening, the second time from the exhaust gas transmission to the air-fuel ratio sensor, and the third time of the steady-state theoretical response of the air-fuel ratio sensor;

[0064] S2. Determine the transient response time correction value according to the theoretical transmission delay of the steady-state air-fuel ratio of the engine and the learning value of the air-fuel ratio state change;

[0065] S3. Determine the engine air-fuel ratio transient transmission delay based on the steady-state theoretical transmission delay and the transient response time correction amount.

[0066] In step S1, a detection device is set to obtain a first time from when a fuel supply instruction is issued to when the system executes to open the exhaust valve, a second time when the exhaust gas is transmitted to the air-fuel ratio sensor, and a third time when the air-fuel ratio sensor responds to a steady-state theoretical response, and the steady-state theoretical transmission delay of the engine air-fuel ratio is determined by the first time, the second time, and the third time;

[0067] In step S2, a transient response time correction amount is determined according to the steady-state theoretical transmission delay of the engine air-fuel ratio and the selected state change learning value;

[0068] In step S3, the steady-state theoretical transmission delay and the transient response time correction determined in step S2 are used to determine the transient delay of the engine air-fuel ratio.

[0069] like Figure 2 As shown, preferably, obtaining the fuel supply instruction to the first time of exhaust valve opening includes the following steps:

[0070] A1. Obtain the crankshaft angle when the engine exhaust valve is open, the crankshaft angle when fuel is supplied, and the engine speed;

[0071] A2. obtaining the first time from the fuel supply instruction to the exhaust valve opening according to the crankshaft angle when the engine exhaust valve is opened, the crankshaft angle when the fuel is supplied, and the engine speed;

[0072] The formula for obtaining the first time from the fuel supply command to the exhaust valve opening is as follows:

[0073] ;

[0074] in, The first time from the fuel supply command to the exhaust valve opening, is the crankshaft angle when the exhaust valve opens, is the crankshaft angle at the time of fuel supply, is the engine speed.

[0075] In step A1, a detection device disposed on an exhaust valve of the engine is used to detect and obtain a crankshaft angle when the exhaust valve is opened, a crankshaft angle when fuel is supplied, and a corresponding engine speed;

[0076] In step A2, the first time from the fuel supply instruction to the exhaust valve opening is determined according to the crank angle when the exhaust valve is opened, the crank angle when the fuel is supplied, the engine speed and the above formula.

[0077] like Figure 3 As shown, preferably, obtaining the second time when the exhaust gas is transmitted to the air-fuel ratio sensor includes the following steps:

[0078] B1. Obtain the exhaust pipe volume and exhaust gas volume flow rate;

[0079] B2. obtaining the second time for the exhaust gas to be transmitted to the air-fuel ratio sensor according to the exhaust pipe volume and the exhaust gas volume flow rate;

[0080] The formula for obtaining the second time of exhaust gas transmission to the air-fuel ratio sensor is as follows:

[0081] ;

[0082] in, The second time that the exhaust gas is transmitted to the air-fuel ratio sensor. is the exhaust pipe volume, is the exhaust gas volume flow rate.

[0083] In step B1, the exhaust pipe volume and the acquired exhaust gas volume flow are detected and acquired by a detection device disposed in the exhaust pipe;

[0084] In step B2, the second time for the exhaust gas to be transmitted to the air-fuel ratio sensor is obtained according to the exhaust pipe volume, the exhaust gas volume flow rate, and the above formula.

[0085] like Figure 4 As shown, preferably, obtaining the exhaust gas volume flow rate includes the following steps:

[0086] C1. Obtain exhaust pipe temperature, exhaust pipe pressure and exhaust gas mass flow rate;

[0087] C2. Obtain the exhaust gas volume flow rate according to the exhaust pipe temperature, exhaust pipe pressure, exhaust gas mass flow rate and ideal gas constant;

[0088] The formula for obtaining the exhaust gas volume flow rate is as follows:

[0089] ;

[0090] in, is the exhaust gas volume flow rate, is the ideal gas constant, is the exhaust pipe temperature, is the exhaust pipe pressure, is the exhaust gas mass flow rate.

[0091] In step C1, the exhaust pipe temperature, the exhaust pipe pressure and the exhaust gas mass flow rate are further detected by a detection device disposed in the exhaust pipe;

[0092] In step C2, the exhaust gas volume flow is calculated and determined according to the exhaust pipe temperature, exhaust pipe pressure, exhaust gas mass flow and ideal gas constant and the above formula, and the exhaust gas volume flow is used to calculate the second time for the exhaust gas to be transmitted to the air-fuel ratio sensor.

[0093] Preferably, the formula for the third time of the steady-state theoretical response of the air-fuel ratio sensor is specifically:

[0094] ;

[0095] in, The third time of the steady-state theoretical response of the air-fuel ratio sensor, is the exhaust gas mass flow rate, is the exhaust pipe temperature.

[0096] In actual application, the third time of the steady-state theoretical response of the air-fuel ratio sensor is determined by the exhaust gas mass flow rate and the exhaust pipe temperature.

[0097] Preferably, the formula for determining the steady-state theoretical transmission delay of the engine air-fuel ratio is specifically:

[0098] ;

[0099] in, is the theoretical transmission delay of the steady-state air-fuel ratio of the engine, The first time from the fuel supply command to the exhaust valve opening, The second time that the exhaust gas is transmitted to the air-fuel ratio sensor. It is the third time of the steady-state theoretical response of the air-fuel ratio sensor.

[0100] During actual use, the first time from the fuel supply command to the exhaust valve opening, the second time from the exhaust gas transmission to the air-fuel ratio sensor, and the third time from the steady-state theoretical response of the air-fuel ratio sensor are summed to obtain the steady-state theoretical transmission delay of the engine air-fuel ratio.

[0101] like Figure 5 As shown, preferably, step S2 includes the following steps:

[0102] D1. Control the fuel supply to increase or decrease to obtain different air-fuel ratio state change curves;

[0103] D2. The deviation between the air-fuel ratio change time period and the steady-state transmission delay is used as the air-fuel ratio state change learning value;

[0104] D3. Select the corresponding air-fuel ratio state change learning value according to the current air-fuel ratio state to obtain the transient response time correction amount.

[0105] In step D1, the air-fuel ratio state change is divided into from lean to rich and from rich to lean by the learning device, the fuel supply amount is controlled to increase or decrease to achieve different air-fuel ratio state changes, and different air-fuel ratio state change curves are integrated to generate;

[0106] In step D2, the deviation between the air-fuel ratio change time period and the steady-state transmission delay in different air-fuel ratio state change curves is used as the air-fuel ratio state change learning value ;

[0107] In step D3, the transient response time correction value Select the corresponding learning value according to the current air-fuel ratio state get.

[0108] Preferably, step S3 comprises the following steps:

[0109] The sum of the steady-state theoretical transmission delay and the transient response time correction is integrated and solved to obtain the transient transmission delay of the engine air-fuel ratio;

[0110] The formula for obtaining the transient transmission delay of the engine air-fuel ratio is as follows:

[0111] ;

[0112] ;

[0113] in, is the transient transmission delay of the engine air-fuel ratio, is the theoretical transmission delay of the steady-state engine air-fuel ratio, is the transient response time correction.

[0114] In actual application, the sum of the steady-state theoretical transmission delay and the transient response time correction is integrated according to the above formula to obtain the transient transmission delay of the engine air-fuel ratio.

[0115] In this embodiment, as shown in the figure, the upper thin solid line is the time-varying transmission delay time, corresponding to the air-fuel ratio transmission delay time caused by the change in engine operating conditions, the lower thick solid line is the air-fuel ratio of the mixture, and the dotted line is the air-fuel ratio after the transmission delay. It can be seen that each air-fuel ratio will reach the end point independently of the transmission delay, which means that no air-fuel ratio is skipped; as long as the transmission delay time remains unchanged, the time when the air-fuel ratio reaches the end point can be accurately calculated; only the transmission delay will affect the time when the air-fuel ratio reaches the end point.

[0116] like Figure 6 As shown, a system for determining engine air-fuel ratio transmission delay includes:

[0117] a steady-state theoretical transmission delay module, for determining a steady-state theoretical transmission delay of an engine air-fuel ratio according to a first time from a fuel supply command to an exhaust valve opening, a second time from exhaust gas transmission to an air-fuel ratio sensor, and a third time of a steady-state theoretical response of the air-fuel ratio sensor;

[0118] A transient response time correction module is used to determine a transient response time correction according to a theoretical transmission delay of a steady-state air-fuel ratio of the engine and a learning value of a state change of the air-fuel ratio;

[0119] The transient transmission delay module is used to determine the transient transmission delay of the engine air-fuel ratio according to the steady-state theoretical transmission delay and the transient response time correction amount.

[0120] In actual application, the present invention also provides an engine air-fuel ratio transmission delay determination system, including a steady-state theoretical transmission delay module, a transient response time correction module and a transient transmission delay module.

[0121] In the embodiments provided in the present application, it should be understood that the disclosed methods and systems can be implemented in other ways. The system embodiments described above are merely schematic. For example, the division of modules is only a logical function division. There may be other division methods in actual implementation, such as: multiple modules or components can be combined, or can be integrated into another system, or some features can be ignored, or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0122] In addition, all functional modules in the embodiments of the present invention may be integrated into one processor, or each module may be a separate device, or two or more modules may be integrated into one device; each functional module in the embodiments of the present invention may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0123] A person of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiment can be completed by program instructions and related hardware. The aforementioned program instructions can be stored in a computer-readable storage medium. When the program instructions are executed, the steps of the above method embodiment are executed; and the aforementioned storage medium includes: a mobile storage device, a read-only memory (ROM), a magnetic disk or an optical disk, and other media that can store program codes.

[0124] It should be understood that the use of "system", "device", "unit" and / or "module" in this application is only a method for distinguishing different components, elements, parts, parts or assemblies at different levels. However, if other words can achieve the same purpose, the word can be replaced by other expressions.

[0125] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "a kind" and / or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements. The elements defined by the sentence "includes a..." do not exclude the existence of other identical elements in the process, method, commodity or device that includes the elements.

[0126] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0127] If a flow chart is used in the present application, the flow chart is used to illustrate the operations performed by the system according to the embodiment of the present application. It should be understood that the preceding or following operations are not necessarily performed accurately in order. On the contrary, each step can be processed in reverse order or simultaneously. At the same time, other operations can also be added to these processes, or a certain step or several steps of operations can be removed from these processes.

[0128] The above is a detailed description of a method and system for determining an engine air-fuel ratio transmission delay provided by the present invention. The above description of the disclosed embodiments enables professionals and technicians in the field to implement or use the present invention. Various modifications to these embodiments will be apparent to professionals and technicians in the field, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features disclosed herein.

Claims

1. A method for determining engine air-fuel ratio transmission delay, characterized in that: The steps include: determining a steady-state theoretical transmission delay of the engine air-fuel ratio based on a first time from a fuel supply command to exhaust valve opening, a second time for exhaust gas to be transmitted to an air-fuel ratio sensor, and a third time for a steady-state theoretical response of the air-fuel ratio sensor; Determining a transient response time correction amount according to the steady-state theoretical transmission delay of the engine air-fuel ratio and a learning value of the air-fuel ratio state change; Determining a transient transmission delay of an engine air-fuel ratio according to the steady-state theoretical transmission delay and the transient response time correction amount; The method of determining the transient response time correction value according to the steady-state theoretical transmission delay of the engine air-fuel ratio and the air-fuel ratio state change learning value comprises the following steps: Control the fuel supply to increase or decrease to obtain different air-fuel ratio state change curves; taking the deviation between the air-fuel ratio change time period in the different air-fuel ratio state change curves and the engine air-fuel ratio steady-state transmission delay as the air-fuel ratio state change learning value; Selecting the corresponding air-fuel ratio state change learning value according to the current air-fuel ratio state to obtain the transient response time correction value; The step of determining the transient transmission delay of the engine air-fuel ratio according to the steady-state theoretical transmission delay and the transient response time correction amount comprises the following steps: Integrating and solving the sum of the steady-state theoretical transmission delay and the transient response time correction amount to obtain the transient transmission delay of the engine air-fuel ratio; The formula for obtaining the transient transmission delay of the engine air-fuel ratio is as follows: ； ； in, is the transient transmission delay of the engine air-fuel ratio, is the theoretical transmission delay of the steady-state air-fuel ratio of the engine, is the transient response time correction.

2. The method for determining engine air-fuel ratio transmission delay according to claim 1, characterized in that: Obtaining the fuel supply instruction to the first time of exhaust valve opening includes the following steps: Obtaining the crankshaft angle when the engine exhaust valve is opened, the crankshaft angle when fuel is supplied, and the engine speed; According to the crankshaft angle when the exhaust valve of the engine is opened, the crankshaft angle when the fuel is supplied, and the engine speed, obtaining the first time from the fuel supply instruction to the exhaust valve opening; The formula for obtaining the first time from the fuel supply instruction to the exhaust valve opening is specifically: ； in, The first time from the fuel supply command to the exhaust valve opening, is the crankshaft angle when the exhaust valve opens, is the crankshaft angle at the time of fuel supply, is the engine speed.

3. The method for determining engine air-fuel ratio transmission delay as claimed in claim 2, characterized in that: The step of obtaining the second time when the exhaust gas is transmitted to the air-fuel ratio sensor comprises the following steps: Obtain the exhaust pipe volume and exhaust gas volume flow rate; acquiring a second time for the exhaust gas to be transmitted to the air-fuel ratio sensor according to the exhaust pipe volume and the exhaust gas volume flow rate; The formula for obtaining the second time for the exhaust gas to be transmitted to the air-fuel ratio sensor is specifically: ； in, The second time that the exhaust gas is transmitted to the air-fuel ratio sensor. is the exhaust pipe volume, is the exhaust gas volume flow rate.

4. The method for determining engine air-fuel ratio transmission delay as claimed in claim 3, characterized in that: Obtaining the exhaust gas volume flow rate comprises the following steps: Obtain exhaust pipe temperature, exhaust pipe pressure and exhaust gas mass flow rate; Obtaining the exhaust gas volume flow rate according to the exhaust pipe temperature, the exhaust pipe pressure, the exhaust gas mass flow rate and the ideal gas constant; The formula for obtaining the exhaust gas volume flow rate is specifically: ； in, is the exhaust gas volume flow rate, is the ideal gas constant, is the exhaust pipe temperature, is the exhaust pipe pressure, is the exhaust gas mass flow rate.

5. The method for determining engine air-fuel ratio transmission delay as claimed in claim 4, characterized in that: The formula for the third time of the steady-state theoretical response of the air-fuel ratio sensor is specifically: ； in, The third time of the steady-state theoretical response of the air-fuel ratio sensor, is the exhaust gas mass flow rate, is the exhaust pipe temperature.

6. The method for determining engine air-fuel ratio transmission delay as claimed in claim 5, characterized in that: The formula for determining the steady-state theoretical transmission delay of the engine air-fuel ratio is specifically: ； in, is the theoretical transmission delay of the steady-state air-fuel ratio of the engine, The first time from the fuel supply command to the exhaust valve opening, The second time that the exhaust gas is transmitted to the air-fuel ratio sensor. It is the third time of the steady-state theoretical response of the air-fuel ratio sensor.

7. An engine air-fuel ratio transmission delay determination system, characterized in that: include: a steady-state theoretical transmission delay module, for determining a steady-state theoretical transmission delay of an engine air-fuel ratio according to a first time from a fuel supply command to an exhaust valve opening, a second time from exhaust gas transmission to an air-fuel ratio sensor, and a third time of a steady-state theoretical response of the air-fuel ratio sensor; A transient response time correction module, used to determine a transient response time correction according to a steady-state theoretical transmission delay of the engine air-fuel ratio and a learning value of an air-fuel ratio state change; A transient transmission delay module, used to determine the transient transmission delay of the engine air-fuel ratio according to the steady-state theoretical transmission delay and the transient response time correction amount; The transient response time correction module is specifically used to control the increase or decrease of the fuel supply to obtain different air-fuel ratio state change curves; taking the deviation between the air-fuel ratio change time period in the different air-fuel ratio state change curves and the engine air-fuel ratio steady-state transmission delay as the air-fuel ratio state change learning value; Selecting the corresponding air-fuel ratio state change learning value according to the current air-fuel ratio state to obtain the transient response time correction amount; The transient transmission delay module is specifically used to integrate and solve the sum of the steady-state theoretical transmission delay and the transient response time correction amount to obtain the transient transmission delay of the engine air-fuel ratio; The formula for obtaining the transient transmission delay of the engine air-fuel ratio is as follows: ； ； in, is the transient transmission delay of the engine air-fuel ratio, is the theoretical transmission delay of the steady-state air-fuel ratio of the engine, is the transient response time correction.

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