Method and device for confirming gas path pressure abnormity of dual-fuel nozzle

Abstract

The invention discloses a method and device for confirming gas path gas pressure abnormity of a dual-fuel nozzle, and relates to the technical field of automobiles. The method comprises the following steps that the current oil-gas pressure difference of an engine is obtained; if the current oil-gas pressure difference of the engine is larger than the first preset oil-gas pressure difference of the engine, the rotating speed roughness of all air cylinders of the engine is obtained; and according to the deviation degree between the rotating speed roughness of each cylinder of the engine and the rotating speed roughness threshold value, determining the position of the cylinder with abnormal air pressure. By acquiring the rotating speed roughness of each cylinder, the position of the cylinder with abnormal air pressure is determined and the abnormal cylinder is locked according to the deviation degree between the rotating speed roughness of each cylinder of the engine and the rotating speed roughness threshold, so that the reliability of the engine is improved. According to the rotating speed roughness of the air cylinder, based on the crankshaft rotating speed signal of the engine, the crankshaft angular acceleration corresponding to the acting stroke of each cylinder is obtained, and whether the air pressure of the current air cylinder is abnormal or not can be judged according to the deviation value of the deviation degree of the crankshaft angular acceleration corresponding to the acting stroke of each cylinder and the rotating speed roughness threshold value.

Description

Technical Field

[0001] The present application relates to the field of automobile technology, and in particular to a method and device for confirming abnormal air pressure in an air path of a dual-fuel nozzle. Background Art

[0002] With the implementation of the National VI Emissions Regulations and the future industry development trend of carbon peak and carbon neutrality, engine alternative fuel technology, dual-fuel injection technology, hybrid technology, etc. are also becoming more mature. Among them, engine dual-fuel direct injection combustion in the cylinder is an important development direction, mainly including diesel + natural gas, diesel + ammonia, diesel + alcohol and other technical solutions. This technical route can maintain the same power and reliability as the diesel engine on the same platform, while having better economy and emission performance. As a key component of this technical route, the dual-fuel nozzle has good performance and reliability, and a complete fault warning and control mechanism, which is the main basis for ensuring good engine performance.

[0003] Since the engine has multiple dual-fuel nozzles, it is difficult to determine the location of the abnormality. The dual-fuel nozzles may have various problems such as oil leakage in the air path, which may cause deterioration of engine performance, uneven combustion in each cylinder, coking and blockage of the nozzle orifices, and other more serious failures, which affect their use. Summary of the invention

[0004] The present application provides a method and device for confirming air pressure anomalies in the air path of a dual-fuel nozzle, so as to improve the existing problems of difficulty in determining the abnormal location, deterioration of engine performance caused by oil blowby in the air path, uneven combustion in each cylinder, coking and blockage of the nozzle orifice, and other more serious faults.

[0005] In a first aspect, the present application provides a method for controlling air pressure in an air path of a dual-fuel nozzle, comprising the following steps:

[0006] Get the current oil-gas pressure difference of the engine;

[0007] If the current oil-gas pressure difference of the engine is greater than the first preset oil-gas pressure difference of the engine, the speed roughness of each cylinder of the engine is obtained;

[0008] The position of the cylinder with abnormal air pressure is determined according to the deviation between the speed roughness of each cylinder of the engine and the speed roughness threshold.

[0009] Since dual-fuel nozzles are generally designed with coaxial dual valves, oil and gas fuels share the same nozzle for injection control. Due to the pressure sealing design of the nozzle needle valve, the lubrication and heat dissipation requirements of the jet needle valve and safety considerations, there is a certain design gap between the oil chamber and the air chamber inside the nozzle. Usually, the oil pressure of the common rail system is higher than the air pressure. Since there is a small design gap (about 5μm) between the oil chamber and the air chamber inside the dual-fuel nozzle, when the nozzle is working normally, due to the oil pressure being higher than the air pressure (10bar~20bar), a small amount of fuel will leak into the air path and be injected into the cylinder along with the jet to participate in combustion. A small amount of fuel leaking into the air path is beneficial to the lubrication and heat dissipation of the jet needle valve, and can also extend the service life of the nozzle.

[0010] The amount of oil leakage in the air circuit of a dual-fuel nozzle changes linearly with the pressure difference between the oil and gas. The greater the pressure difference between the oil and gas, the greater the amount of oil leakage. If the pressure difference between the oil and gas is too large or the dual-fuel nozzle fails, the amount of oil leakage into the air circuit will increase, and even the fuel may leak back into the air rail, which will cause problems such as deterioration of engine combustion, poor consistency of each cylinder, and coking and blockage of the spray hole, seriously affecting the performance of the vehicle and driving experience.

[0011] Considering the pipeline pressure drop, the gas inlet pressure of the engine is usually lower than the gas pressure at the outlet of the engine oil and gas balance valve. If the gas inlet pressure of the engine is higher than the gas pressure at the outlet of the engine oil and gas balance valve, it is considered that the gas rail pressure is abnormal and there is a risk of oil leakage in the gas path. When the oil and gas pressure difference is often caused by excessive oil leakage in the gas path due to nozzle needle valve wear, it is necessary to determine the fault location and eliminate the hidden danger in time.

[0012] The present application obtains the speed roughness of each cylinder, determines the position of the cylinder with abnormal air pressure according to the deviation between the speed roughness of each cylinder of the engine and the speed roughness threshold, locks the abnormal cylinder, and improves the reliability of the engine. The speed roughness of the cylinder is based on the crankshaft angular acceleration corresponding to the power stroke of each cylinder obtained by the engine crankshaft speed signal. According to the deviation value of the deviation between the crankshaft angular acceleration corresponding to the power stroke of each cylinder and the speed roughness threshold, it can be judged whether the current cylinder has abnormal air pressure. The speed roughness threshold can be determined by the standard map of the speed roughness threshold corresponding to each cylinder under different working conditions and pre-calibrated in the control system. When the engine is working normally, the consistency of the injection and combustion work of each cylinder is good, so the crankshaft angular acceleration corresponding to the work of each cylinder is at the same level. If a cylinder has abnormal injection and combustion, it will cause a large difference between the combustion work of the cylinder and other cylinders, so that the crankshaft angular acceleration corresponding to the work of the cylinder is abnormal. When it exceeds the threshold (pre-calibrated) when the engine can maintain normal operation at this working point, it can be confirmed that the cylinder is working abnormally. If the whole machine gas rail pressure is abnormal at the same time, it can be confirmed that the gas path of the cylinder is abnormal. The first preset oil-gas pressure difference of the engine can be calibrated according to the actual working conditions, or it can be a set fixed value, such as 20-40 bar.

[0013] After confirming that the current cylinder gas circuit is abnormal, the following measures can be taken: report faults related to abnormal oil flow in the gas circuit to remind the driver to go to the station as soon as possible for processing; according to actual platform needs, limit the engine torque after reporting the fault to ensure safety; correct and limit the injection amount of the faulty cylinder, for example, control the injection and jet of the dual-fuel nozzle of the faulty cylinder according to the minimum safe oil amount of the nozzle to prevent fuel flooding in the cylinder.

[0014] In some embodiments, determining the cylinder position with abnormal air pressure according to the deviation between the speed roughness of each cylinder of the engine and the speed roughness threshold comprises:

[0015] Comparing the absolute value of the difference between the speed roughness of each cylinder and the speed roughness of a preset cylinder with the size of the preset difference;

[0016] If the absolute value of the difference between the rotational speed roughness in the cylinder and the rotational speed roughness of the preset cylinder is greater than the preset difference, it is determined that the cylinder is a cylinder with abnormal gas path pressure.

[0017] When the vehicle is running normally, each cylinder of the engine performs combustion and work in the normal ignition sequence of 1-5-3-6-2-4, the air volume, injection volume and combustion work of each cylinder are relatively consistent, and the overall operation of the engine is relatively smooth. Therefore, when there is no gas path failure, the speed roughness of each cylinder of the engine runs at the same level, and the speed roughness of each cylinder runs within the speed roughness range of the preset cylinder, where the speed roughness of the preset cylinder can be set in advance according to the working conditions, for example, it can be 30~100r / s 2 range. When the gas circuit of some cylinders is abnormal, the speed roughness of the abnormal cylinder will deviate from the speed roughness of the preset cylinder. By comparing the absolute value of the difference between the speed roughness of each cylinder and the speed roughness of the preset cylinder with the preset difference, it can be determined whether the cylinder has abnormal gas circuit pressure. Usually, when the absolute value of the difference between the speed roughness and the speed roughness of the preset cylinder is greater than 30% of the speed roughness of the preset cylinder, the cylinder is considered to have abnormal gas circuit pressure. It should be noted that the number of cylinders with abnormal gas circuit pressure can be one or more. As long as the absolute value of the difference between the speed roughness of the cylinder and the speed roughness of the preset cylinder is greater than the preset difference, it is considered to be abnormal.

[0018] In some embodiments, if the absolute value of the difference between the speed roughness in the cylinder and the speed roughness of the preset cylinder is greater than the preset difference, then judging that the cylinder is a cylinder with abnormal gas path pressure includes:

[0019] If the absolute value of the difference between the speed roughness of the cylinder and the speed roughness of the preset cylinder is greater than the preset difference, compare the ratio of the speed roughness of the cylinder to the speed roughness of other normal cylinders;

[0020] If the ratio of the speed roughness of the cylinder to the speed roughness of other normal cylinders exceeds a preset ratio range, the cylinder is determined to be a cylinder with abnormal gas path pressure.

[0021] In order to improve the accuracy of fault judgment and eliminate the influence of cylinder dispersion on judgment, when the absolute value of the difference between the speed roughness of the cylinder and the speed roughness of the preset cylinder is greater than the preset difference, the ratio of the speed roughness of the cylinder to the speed roughness of other normal cylinders is further compared. If the ratio of the speed roughness of the cylinder to the speed roughness of other normal cylinders exceeds the preset ratio range, the cylinder is judged to be a cylinder with abnormal gas path pressure. It should be noted that the other cylinders here refer to cylinders whose absolute value of the difference between the speed roughness and the speed roughness of the preset cylinder is less than or equal to the preset difference, that is, they are defaulted to normal cylinders. When the suspected abnormal cylinder is further compared with the default normal cylinder in terms of the speed roughness ratio, it can be further confirmed that the suspected abnormal cylinder is an abnormal cylinder, reducing the influence of cylinder dispersion. Usually, the preset ratio range can be in the range of 1.15 to 1.25.

[0022] In some embodiments, if the current oil-gas pressure difference of the engine is greater than the first preset oil-gas pressure difference of the engine, the speed roughness of each cylinder of the engine is obtained, and the speed roughness of the cylinder is α1, which satisfies:

[0023] α1=d(2π*N) / dt;

[0024] Wherein, N is the engine speed;

[0025] t is time.

[0026] The speed roughness of the cylinder is the crankshaft angular acceleration of the cylinder, which is the derivative of the crankshaft speed of the cylinder with respect to time. The crankshaft speed of the cylinder is related to the speed. The speed roughness of the cylinder can be obtained through the speed and time.

[0027] In some embodiments, after obtaining the current oil-gas pressure difference of the engine, the method further includes:

[0028] If the engine's oil-gas pressure difference is greater than the second preset engine's oil-gas pressure difference and less than the first preset engine's oil-gas pressure difference, adjust the fuel pressure so that the degree of deviation between the oil-gas pressure difference and the target pressure difference is less than or equal to the oil-gas pressure difference deviation degree threshold.

[0029] The existing dual-fuel nozzle gas path oil leakage control is mainly achieved from the design side by controlling the nozzle design gap and the oil-gas pressure difference. This solution does not take into account the changes in the oil-gas pressure difference during actual application, such as insufficient air pressure caused by lack of air in the gas cylinder and the increase in the needle valve gap caused by the wear of the nozzle needle valve. These factors will cause the gas path oil leakage to increase, thus adversely affecting the performance and reliability of the engine.

[0030] If the oil-gas pressure difference of the engine is greater than the second preset oil-gas pressure difference of the engine, and less than the first preset oil-gas pressure difference of the engine, the first preset oil-gas pressure difference of the engine is an abnormally dangerous pressure difference value, and the second preset oil-gas pressure difference of the engine is an abnormally warning pressure difference value, that is, when the oil-gas pressure difference of the engine deviates from the normal value range, but has not yet reached a dangerous level, the fuel pressure can be adjusted so that the oil-gas pressure difference is within the preset range and does not exceed the abnormal warning pressure difference value, thereby stabilizing the oil-gas pressure difference and reducing oil blowby. The first preset oil-gas pressure difference of the engine is greater than the second preset oil-gas pressure difference of the engine, and the second preset oil-gas pressure difference of the engine can be calibrated according to actual working conditions, or it can be a set fixed value, such as 10 to 20 bar, and the first preset oil-gas pressure difference of the engine can be calibrated according to actual working conditions, or it can be a set fixed value, such as 20 to 40 bar.

[0031] In some embodiments, if the fuel-gas pressure difference of the engine is greater than the second preset fuel-gas pressure difference of the engine and less than the first preset fuel-gas pressure difference of the engine, adjusting the fuel pressure so that the degree of deviation between the fuel-gas pressure difference and the target pressure difference is less than or equal to the fuel-gas pressure difference deviation degree threshold comprises:

[0032] If the engine oil-gas pressure difference is greater than the second preset engine oil-gas pressure difference and less than the first preset engine oil-gas pressure difference, obtaining an engine oil-gas pressure difference correction value according to the degree of deviation between the current engine oil-gas pressure difference and the target engine pressure difference;

[0033] The fuel pressure at the fuel inlet of the engine is corrected according to the engine oil-gas pressure difference correction value so that the degree of deviation between the current engine oil-gas pressure difference and the target pressure difference of the engine is less than or equal to the engine oil-gas pressure difference deviation degree threshold.

[0034] By increasing the monitoring of the common rail oil pressure, i.e., the engine inlet oil pressure and the engine oil-gas balance valve outlet air pressure, the current oil-gas pressure difference of the engine is monitored in real time, and the current oil-gas pressure difference of the engine is compared with the target pressure difference. If the current oil-gas pressure difference of the engine deviates too much from the target pressure difference, it is considered that the current oil-gas pressure difference of the engine is too large. At this time, the engine oil-gas pressure difference is corrected to obtain the correction value of the engine oil-gas pressure difference. According to the correction value of the engine oil-gas pressure difference, the fuel pressure at the fuel inlet of the engine is corrected, so that the degree of deviation between the current oil-gas pressure difference of the engine and the target pressure difference of the engine is less than or equal to the deviation degree threshold, so that the oil-gas pressure difference of the engine maintains a dynamically stable pressure difference range, the oil-gas pressure difference is guaranteed to be within a safe range, the amount of oil blowby in the gas path is reduced, and the problems of engine performance deterioration, uneven combustion of each cylinder, and coking and clogging of the nozzle orifice are improved. Usually, the target pressure difference of the engine is 10 to 15 bar.

[0035] It should be noted that before controlling the steady-state balance of the oil-gas pressure difference, it is necessary to perform closed-loop control of the gas cylinder gas supply boost pressure to keep the actual gas supply pressure consistent with the target gas supply pressure. If the gas cylinder gas supply pressure is normal, the gas supply pressure of the engine is normal. Usually, based on the actual gas supply pressure and the minimum gas supply pressure, it can be judged whether the current engine gas supply pressure is normal: if the actual gas supply pressure ≤ the minimum gas supply pressure, a low gas cylinder supply pressure fault is reported; if the minimum gas supply pressure < the actual gas supply pressure ≤ the actual fuel rail pressure, the gas supply pressure is considered normal.

[0036] If the degree of deviation between the current oil-gas pressure difference of the engine and the target pressure difference of the engine is greater than the deviation threshold, that is, the current oil-gas pressure difference of the engine is too large, then the current oil-gas pressure difference of the engine is corrected, and the difference between the target pressure difference of the engine and the current oil-gas pressure difference of the engine is the oil-gas pressure difference correction value of the engine. It should be noted that the target pressure difference of the engine may be different under different working conditions. For example, the target pressure difference of the engine under certain working conditions is 10 bar, the target pressure difference of the engine under certain working conditions is 12 bar, and the target pressure difference of the engine under certain working conditions is 15 bar. It can be selected according to the actual situation. By correcting the current oil-gas pressure difference of the engine, the current oil-gas pressure difference of the engine can be made closer to the target pressure difference, and the oil-gas pressure difference of the engine can be stabilized in a safe range of dynamic balance, thereby reducing the situation of large amounts of oil blowby in the gas path and improving engine performance.

[0037] In some embodiments, the actual fuel pressure at the fuel inlet of the engine is P1, the actual fuel pressure at the outlet of the engine oil-gas balance valve is P2, the corrected fuel pressure of the engine is P3, the current fuel-gas pressure difference of the engine is ΔP1, the target pressure difference of the engine is ΔP, and the corrected fuel-gas pressure difference of the engine is ΔP2, which satisfies:

[0038] △P1=P1-P2;

[0039] △P2=△P-△P1;

[0040] △P=P3-P2;

[0041] P3=P1+△P1+△P2.

[0042] By adding the engine oil-gas pressure difference correction value to the fuel pressure at the engine's fuel inlet, the fuel pressure at the engine's fuel inlet is corrected, so that the corrected oil-gas pressure difference value can be closer to the target oil-gas pressure difference value, and the engine's oil-gas pressure difference value can be dynamically stabilized. It should be noted that at the end of the use of the gas tank, due to insufficient gas in the gas tank, the gas pressure difference cannot be controlled to increase. At this time, only the fuel pressure at the engine's fuel inlet can be controlled. By adding the difference to the fuel pressure at the engine's fuel inlet, the oil-gas pressure difference can be controlled, so that the current engine's oil-gas pressure difference can be closer to the target pressure difference, and the engine's oil-gas pressure difference can be stabilized in a safe range of dynamic balance, thereby reducing the situation of large amounts of oil blowby in the gas circuit and improving engine performance.

[0043] In some embodiments, if the fuel-gas pressure difference of the engine is greater than the second preset fuel-gas pressure difference of the engine and less than the first preset fuel-gas pressure difference of the engine, adjusting the fuel pressure so that the degree of deviation between the fuel-gas pressure difference and the target pressure difference is less than or equal to the fuel-gas pressure difference deviation degree threshold comprises:

[0044] If the oil-gas pressure difference of the engine is greater than the second preset oil-gas pressure difference of the engine and less than the first preset oil-gas pressure difference of the engine, obtaining the oil-gas pressure difference of each cylinder of the engine;

[0045] If the oil-gas pressure difference of the cylinder is greater than the second preset oil-gas pressure difference of the cylinder and less than the first preset oil-gas pressure difference of the cylinder, a cylinder oil-gas pressure difference correction value is obtained according to the degree of deviation between the current oil-gas pressure difference of the cylinder and the target pressure difference of the cylinder;

[0046] The fuel pressure of the cylinder is corrected according to the cylinder oil-gas pressure difference correction value so that the deviation degree between the current oil-gas pressure difference of the cylinder and the target pressure difference of the cylinder is less than or equal to the cylinder oil-gas pressure difference deviation degree threshold.

[0047] When the needle valve clearance caused by the wear of the cylinder nozzle needle valve increases, it affects the oil-gas pressure difference of the current cylinder, but does not affect the oil-gas pressure difference of other cylinders. At this time, adjustments can be made for a single cylinder. When the oil-gas pressure difference of a cylinder is greater than the oil-gas pressure difference of the second preset cylinder and less than the oil-gas pressure difference of the first preset cylinder, the oil-gas pressure difference of the first preset cylinder is a dangerous value, usually a serious abnormal situation such as damage or failure, and the oil-gas pressure difference of the second preset cylinder is a warning value, usually a natural situation such as wear of the cylinder nozzle needle valve. Therefore, the fuel pressure of the cylinder is corrected within the dangerous value, so that the deviation degree of the current oil-gas pressure difference of the cylinder from the target pressure difference of the cylinder is less than or equal to the cylinder oil-gas pressure difference deviation degree threshold, which can stabilize the oil-gas pressure difference of the abnormal cylinder, while not affecting the operation of other cylinders, reducing the situation of large amount of oil in the gas path, and improving engine performance. Among them, the oil-gas pressure difference of the first preset cylinder is greater than the oil-gas pressure difference of the second preset cylinder, and its specific value can be calibrated in advance according to the actual working conditions.

[0048] In some embodiments, the fuel pressure of the cylinder is P4, the gas pressure of the cylinder is P5, the corrected fuel pressure of the cylinder is P6, the oil-gas pressure difference of the cylinder is ΔP3, the target pressure difference of the cylinder is ΔP', and the oil-gas pressure difference correction value of the cylinder is ΔP4, which satisfies:

[0049] △P3=P4-P5;

[0050] △P4=△P'-△P3;

[0051] △P'=P6-P5;

[0052] P6=P4+△P3+△P4.

[0053] Due to the abnormality of the air circuit, the air pressure is difficult to adjust. The oil pressure difference of the cylinder can be controlled within the appropriate range by correcting the oil pressure.

[0054] In a second aspect, the present application provides a device for confirming abnormal gas pressure in a gas path of a dual-fuel nozzle, comprising:

[0055] A first acquisition unit, used to acquire the current oil-gas pressure difference of the engine;

[0056] a second acquisition unit, configured to acquire the speed roughness of each cylinder of the engine if the current oil-gas pressure difference of the engine is greater than a first preset oil-gas pressure difference of the engine; and

[0057] The execution unit is used to determine the cylinder position with abnormal air pressure according to the deviation between the speed roughness of each cylinder of the engine and the speed roughness threshold.

[0058] By obtaining the speed roughness of each cylinder, according to the deviation between the speed roughness of each cylinder of the engine and the speed roughness threshold, the position of the cylinder with abnormal air pressure is determined, and the abnormal cylinder is locked to improve the reliability of the engine. The speed roughness of the cylinder is based on the crankshaft angular acceleration corresponding to the power stroke of each cylinder obtained based on the engine crankshaft speed signal. According to the deviation value of the deviation between the crankshaft angular acceleration corresponding to the power stroke of each cylinder and the speed roughness threshold, it can be judged whether the current cylinder has abnormal air pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments 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 creative work.

[0060] Figure 1 The present invention is a flowchart of a method for confirming abnormal gas pressure in a gas path of a dual-fuel nozzle according to an embodiment of the present invention.

[0061] Figure 2 The present invention is a flowchart of a method for confirming abnormal gas pressure in a gas path of a dual-fuel nozzle according to an embodiment of the present invention.

[0062] Figure 3 The present invention is a flowchart of a method for confirming abnormal gas pressure in a gas path of a dual-fuel nozzle according to an embodiment of the present invention.

[0063] Figure 4 The present invention is a flowchart of a method for confirming abnormal gas pressure in a gas path of a dual-fuel nozzle according to an embodiment of the present invention.

[0064] Figure 5 The present invention is a flowchart of a method for confirming abnormal gas pressure in a gas path of a dual-fuel nozzle according to an embodiment of the present invention.

[0065] Figure 6 The present invention is a flowchart of a method for confirming abnormal gas pressure in a gas path of a dual-fuel nozzle according to an embodiment of the present invention.

[0066] Figure 7 Schematic diagram of a device for confirming abnormal gas pressure in a gas path of a dual-fuel nozzle according to an embodiment of the present application. DETAILED DESCRIPTION

[0067] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0068] With the implementation of the National VI Emissions Regulations and the future industry development trend of carbon peak and carbon neutrality, engine alternative fuel technology, dual-fuel injection technology, hybrid technology, etc. are also becoming more mature. Among them, engine dual-fuel direct injection combustion in the cylinder is an important development direction, mainly including diesel + natural gas, diesel + ammonia, diesel + alcohol and other technical solutions. This technical route can maintain the same power and reliability as the diesel engine on the same platform, while having better economy and emission performance. As a key component of this technical route, the dual-fuel nozzle has good performance and reliability, and a complete fault warning and control mechanism, which is the main basis for ensuring good engine performance.

[0069] Dual-fuel nozzles have various problems such as oil blowby in the air path causing deterioration of engine performance, uneven combustion in each cylinder, coking and blockage of the nozzle orifices, and other more serious failures, which affect their use.

[0070] In view of this, the present application provides a method and device for confirming abnormal air pressure in the air path of a dual-fuel nozzle, so as to improve the existing problems that the fault location is difficult to confirm, the engine performance deterioration caused by oil leakage in the air path, uneven combustion in each cylinder, coking and blockage of the nozzle orifice, and other more serious faults.

[0071] First, as Figure 1 As shown, the present application provides a method for controlling the air pressure of an air path of a dual-fuel nozzle, comprising the following steps:

[0072] S100, obtaining the current oil-gas pressure difference of the engine;

[0073] S200, if the current oil-gas pressure difference of the engine is greater than a first preset oil-gas pressure difference of the engine, obtaining the speed roughness of each cylinder of the engine;

[0074] S300: Determine the position of the cylinder with abnormal air pressure according to the deviation between the speed roughness of each cylinder of the engine and the speed roughness threshold.

[0075] Since dual-fuel nozzles are generally designed with coaxial dual valves, oil and gas fuels share the same nozzle for injection control. Due to the pressure sealing design of the nozzle needle valve, the lubrication and heat dissipation requirements of the jet needle valve and safety considerations, there is a certain design gap between the oil chamber and the air chamber inside the nozzle. Usually, the oil pressure of the common rail system is higher than the air pressure. Since there is a small design gap (about 5μm) between the oil chamber and the air chamber inside the dual-fuel nozzle, when the nozzle is working normally, due to the oil pressure being higher than the air pressure (10bar~20bar), a small amount of fuel will leak into the air path and be injected into the cylinder along with the jet to participate in combustion. A small amount of fuel leaking into the air path is beneficial to the lubrication and heat dissipation of the jet needle valve, and can also extend the service life of the nozzle.

[0076] The amount of oil leakage in the air circuit of a dual-fuel nozzle changes linearly with the pressure difference between the oil and gas. The greater the pressure difference between the oil and gas, the greater the oil leakage. If the pressure difference between the oil and gas is too large or the dual-fuel nozzle fails, the amount of oil leakage into the air circuit will increase, and even the fuel will leak back into the air rail, which will cause problems such as deterioration of engine combustion, poor consistency of each cylinder, and coking and blockage of the spray hole, seriously affecting the performance of the vehicle and driving experience.

[0077] Considering the pipeline pressure drop, the gas inlet pressure of the engine is usually lower than the gas pressure at the outlet of the engine oil and gas balance valve. If the gas inlet pressure of the engine is higher than the gas pressure at the outlet of the engine oil and gas balance valve, it is considered that the gas rail pressure is abnormal and there is a risk of oil leakage in the gas path. When the oil and gas pressure difference is often caused by excessive oil leakage in the gas path due to nozzle needle valve wear, it is necessary to determine the fault location and eliminate the hidden danger in time.

[0078] The present application obtains the speed roughness of each cylinder, determines the position of the cylinder with abnormal air pressure according to the deviation between the speed roughness of each cylinder of the engine and the speed roughness threshold, locks the abnormal cylinder, and improves the reliability of the engine. The speed roughness of the cylinder is based on the crankshaft angular acceleration corresponding to the power stroke of each cylinder obtained by the engine crankshaft speed signal. According to the deviation value of the deviation between the crankshaft angular acceleration corresponding to the power stroke of each cylinder and the speed roughness threshold, it can be judged whether the current cylinder has abnormal air pressure. The speed roughness threshold can be determined by the standard map of the speed roughness threshold corresponding to each cylinder under different working conditions and pre-calibrated in the control system. When the engine is working normally, the consistency of the injection and combustion work of each cylinder is good, so the crankshaft angular acceleration corresponding to the work of each cylinder is at the same level. If a cylinder has abnormal injection and combustion, it will cause a large difference between the combustion work of the cylinder and other cylinders, so that the crankshaft angular acceleration corresponding to the work of the cylinder is abnormal. When it exceeds the threshold (pre-calibrated) when the engine can maintain normal operation at this working point, it can be confirmed that the cylinder is working abnormally. If the whole machine gas rail pressure is abnormal at the same time, it can be confirmed that the gas path of the cylinder is abnormal. The first preset oil-gas pressure difference of the engine can be calibrated according to the actual working conditions, or it can be a set fixed value, such as 20-40 bar.

[0079] After confirming that the current cylinder gas circuit is abnormal, the following measures can be taken: report faults related to abnormal oil flow in the gas circuit to remind the driver to go to the station as soon as possible for processing; according to actual platform needs, limit the engine torque after reporting the fault to ensure safety; correct and limit the injection amount of the faulty cylinder, for example, control the injection and jet of the dual-fuel nozzle of the faulty cylinder according to the minimum safe oil amount of the nozzle to prevent fuel flooding in the cylinder.

[0080] Combined with the first aspect, Figure 2 As shown, in some embodiments provided in the present application, determining the cylinder position with abnormal air pressure according to the deviation between the speed roughness of each cylinder of the engine and the speed roughness threshold includes:

[0081] S301, comparing the absolute value of the difference between the speed roughness of each cylinder and the speed roughness of a preset cylinder with the preset difference;

[0082] S302: If the absolute value of the difference between the speed roughness in the cylinder and the speed roughness of the preset cylinder is greater than the preset difference, the cylinder is determined to be a cylinder with abnormal gas path pressure.

[0083] When the vehicle is running normally, each cylinder of the engine performs combustion and work in the normal ignition sequence of 1-5-3-6-2-4, the air volume, injection volume and combustion work of each cylinder are relatively consistent, and the overall operation of the engine is relatively smooth. Therefore, when there is no gas path failure, the speed roughness of each cylinder of the engine runs at the same level, and the speed roughness of each cylinder runs within the speed roughness range of the preset cylinder, where the speed roughness of the preset cylinder can be set in advance according to the working conditions, for example, it can be 30~100r / s 2 range. When the gas circuit of some cylinders is abnormal, the speed roughness of the abnormal cylinder will deviate from the speed roughness of the preset cylinder. By comparing the absolute value of the difference between the speed roughness of each cylinder and the speed roughness of the preset cylinder with the preset difference, it can be determined whether the cylinder has abnormal gas circuit pressure. Usually, when the absolute value of the difference between the speed roughness and the speed roughness of the preset cylinder is greater than 30% of the speed roughness of the preset cylinder, the cylinder is considered to have abnormal gas circuit pressure. It should be noted that the number of cylinders with abnormal gas circuit pressure can be one or more. As long as the absolute value of the difference between the speed roughness of the cylinder and the speed roughness of the preset cylinder is greater than the preset difference, it is considered to be abnormal.

[0084] Combined with the first aspect, Figure 3 As shown, in some embodiments provided in the present application, if the absolute value of the difference between the speed roughness in the cylinder and the speed roughness of the preset cylinder is greater than the preset difference, then judging that the cylinder is a cylinder with abnormal gas path pressure includes:

[0085] S3021. If the absolute value of the difference between the speed roughness of the cylinder and the speed roughness of the preset cylinder is greater than the preset difference, compare the ratio of the speed roughness of the cylinder to the speed roughness of other normal cylinders;

[0086] S3022: If the ratio of the speed roughness of the cylinder to the speed roughness of other normal cylinders exceeds a preset ratio range, the cylinder is determined to be a cylinder with abnormal gas path pressure.

[0087] In order to improve the accuracy of fault judgment and eliminate the influence of cylinder dispersion on judgment, when the absolute value of the difference between the speed roughness of the cylinder and the speed roughness of the preset cylinder is greater than the preset difference, the ratio of the speed roughness of the cylinder to the speed roughness of other normal cylinders is further compared. If the ratio of the speed roughness of the cylinder to the speed roughness of other normal cylinders exceeds the preset ratio range, the cylinder is judged to be a cylinder with abnormal gas path pressure. It should be noted that the other cylinders here refer to cylinders whose absolute value of the difference between the speed roughness and the speed roughness of the preset cylinder is less than or equal to the preset difference, that is, they are defaulted to normal cylinders. When the suspected abnormal cylinder is further compared with the default normal cylinder in terms of the speed roughness ratio, it can be further confirmed that the suspected abnormal cylinder is an abnormal cylinder, reducing the influence of cylinder dispersion. Usually, the preset ratio range can be in the range of 1.15 to 1.25.

[0088] In combination with the first aspect, in some embodiments provided in the present application, if the current oil-gas pressure difference of the engine is greater than the first preset oil-gas pressure difference of the engine, then in obtaining the speed roughness of each cylinder of the engine, the speed roughness of the cylinder is α1, satisfying:

[0089] α1=d(2π*N) / dt;

[0090] Wherein, N is the engine speed;

[0091] t is time.

[0092] The speed roughness of the cylinder is the crankshaft angular acceleration of the cylinder, which is the derivative of the crankshaft speed of the cylinder with respect to time. The crankshaft speed of the cylinder is related to the speed. The speed roughness of the cylinder can be obtained through the speed and time.

[0093] Combined with the first aspect, Figure 4 As shown, in some embodiments provided in the present application, after obtaining the current oil-gas pressure difference of the engine, the method further includes:

[0094] S400. If the engine oil-gas pressure difference is greater than the second preset engine oil-gas pressure difference and less than the first preset engine oil-gas pressure difference, adjust the fuel pressure so that the deviation between the oil-gas pressure difference and the target pressure difference is less than or equal to the oil-gas pressure difference deviation threshold.

[0095] The existing dual-fuel nozzle gas path oil leakage control is mainly achieved from the design side by controlling the nozzle design gap and the oil-gas pressure difference. This solution does not take into account the changes in the oil-gas pressure difference during actual application, such as insufficient air pressure caused by lack of air in the gas cylinder and the increase in the needle valve gap caused by the wear of the nozzle needle valve. These factors will cause the gas path oil leakage to increase, thus adversely affecting the performance and reliability of the engine.

[0096] If the oil-gas pressure difference of the engine is greater than the second preset oil-gas pressure difference of the engine, and less than the first preset oil-gas pressure difference of the engine, the first preset oil-gas pressure difference of the engine is an abnormally dangerous pressure difference value, and the second preset oil-gas pressure difference of the engine is an abnormally warning pressure difference value, that is, when the oil-gas pressure difference of the engine deviates from the normal value range, but has not yet reached a dangerous level, the fuel pressure can be adjusted so that the oil-gas pressure difference is within the preset range and does not exceed the abnormal warning pressure difference value, thereby stabilizing the oil-gas pressure difference and reducing oil blowby. The first preset oil-gas pressure difference of the engine is greater than the second preset oil-gas pressure difference of the engine, and the second preset oil-gas pressure difference of the engine can be calibrated according to actual working conditions, or it can be a set fixed value, such as 10 to 20 bar, and the first preset oil-gas pressure difference of the engine can be calibrated according to actual working conditions, or it can be a set fixed value, such as 20 to 40 bar.

[0097] Combined with the first aspect, Figure 5 As shown, in some embodiments provided in the present application, if the fuel-gas pressure difference of the engine is greater than the second preset fuel-gas pressure difference of the engine and less than the first preset fuel-gas pressure difference of the engine, adjusting the fuel pressure so that the degree of deviation between the fuel-gas pressure difference and the target pressure difference is less than or equal to the fuel-gas pressure difference deviation degree threshold includes:

[0098] S401, if the engine oil-gas pressure difference is greater than the second preset engine oil-gas pressure difference and less than the first preset engine oil-gas pressure difference, obtaining an engine oil-gas pressure difference correction value according to the degree of deviation between the current engine oil-gas pressure difference and the target engine pressure difference;

[0099] S402. Correct the fuel pressure at the fuel inlet of the engine according to the engine oil-gas pressure difference correction value so that the degree of deviation between the current engine oil-gas pressure difference and the target pressure difference of the engine is less than or equal to the engine oil-gas pressure difference deviation degree threshold.

[0100] By increasing the monitoring of the common rail oil pressure, i.e., the engine inlet oil pressure and the engine oil-gas balance valve outlet air pressure, the current oil-gas pressure difference of the engine is monitored in real time, and the current oil-gas pressure difference of the engine is compared with the target pressure difference. If the current oil-gas pressure difference of the engine deviates too much from the target pressure difference, it is considered that the current oil-gas pressure difference of the engine is too large. At this time, the engine oil-gas pressure difference is corrected to obtain the correction value of the engine oil-gas pressure difference. According to the correction value of the engine oil-gas pressure difference, the fuel pressure at the fuel inlet of the engine is corrected, so that the degree of deviation between the current oil-gas pressure difference of the engine and the target pressure difference of the engine is less than or equal to the deviation degree threshold, so that the oil-gas pressure difference of the engine maintains a dynamically stable pressure difference range, the oil-gas pressure difference is guaranteed to be within a safe range, the amount of oil blowby in the gas path is reduced, and the problems of engine performance deterioration, uneven combustion of each cylinder, and coking and clogging of the nozzle orifice are improved. Usually, the target pressure difference of the engine is 10 to 15 bar.

[0101] It should be noted that before controlling the steady-state balance of the oil-gas pressure difference, it is necessary to perform closed-loop control of the gas cylinder gas supply boost pressure to keep the actual gas supply pressure consistent with the target gas supply pressure. If the gas cylinder gas supply pressure is normal, the gas supply pressure of the engine is normal. Usually, based on the actual gas supply pressure and the minimum gas supply pressure, it can be judged whether the current engine gas supply pressure is normal: if the actual gas supply pressure ≤ the minimum gas supply pressure, a low gas cylinder supply pressure fault is reported; if the minimum gas supply pressure < the actual gas supply pressure ≤ the actual fuel rail pressure, the gas supply pressure is considered normal.

[0102] If the degree of deviation between the current oil-gas pressure difference of the engine and the target pressure difference of the engine is greater than the deviation threshold, that is, the current oil-gas pressure difference of the engine is too large, then the current oil-gas pressure difference of the engine is corrected, and the difference between the target pressure difference of the engine and the current oil-gas pressure difference of the engine is the oil-gas pressure difference correction value of the engine. It should be noted that the target pressure difference of the engine may be different under different working conditions. For example, the target pressure difference of the engine under certain working conditions is 10 bar, the target pressure difference of the engine under certain working conditions is 12 bar, and the target pressure difference of the engine under certain working conditions is 15 bar. It can be selected according to the actual situation. By correcting the current oil-gas pressure difference of the engine, the current oil-gas pressure difference of the engine can be made closer to the target pressure difference, and the oil-gas pressure difference of the engine can be stabilized in a safe range of dynamic balance, thereby reducing the situation of large amounts of oil blowby in the gas path and improving engine performance.

[0103] In combination with the first aspect, in some embodiments provided in the present application, the actual fuel pressure at the fuel inlet of the engine is P1, the actual fuel pressure at the outlet of the engine oil-gas balance valve is P2, the corrected fuel pressure of the engine is P3, the current oil-gas pressure difference of the engine is △P1, the target pressure difference of the engine is △P, and the oil-gas pressure difference correction value of the engine is △P2, which satisfies:

[0104] △P1=P1-P2;

[0105] △P2=△P-△P1;

[0106] △P=P3-P2;

[0107] P3=P1+△P1+△P2.

[0108] By adding the engine oil-gas pressure difference correction value to the fuel pressure at the engine's fuel inlet, the fuel pressure at the engine's fuel inlet is corrected, so that the corrected oil-gas pressure difference value can be closer to the target oil-gas pressure difference value, and the engine's oil-gas pressure difference value can be dynamically stabilized. It should be noted that at the end of the use of the gas tank, due to insufficient gas in the gas tank, the gas pressure difference cannot be controlled to increase. At this time, only the fuel pressure at the engine's fuel inlet can be controlled. By adding the difference to the fuel pressure at the engine's fuel inlet, the oil-gas pressure difference can be controlled, so that the current engine's oil-gas pressure difference can be closer to the target pressure difference, and the engine's oil-gas pressure difference can be stabilized in a safe range of dynamic balance, thereby reducing the situation of large amounts of oil blowby in the gas circuit and improving engine performance.

[0109] Combined with the first aspect, Figure 6 As shown, in some embodiments provided in the present application, if the fuel-gas pressure difference of the engine is greater than the second preset fuel-gas pressure difference of the engine and less than the first preset fuel-gas pressure difference of the engine, adjusting the fuel pressure so that the degree of deviation between the fuel-gas pressure difference and the target pressure difference is less than or equal to the fuel-gas pressure difference deviation degree threshold includes:

[0110] S403, if the oil-gas pressure difference of the engine is greater than the second preset oil-gas pressure difference of the engine and less than the first preset oil-gas pressure difference of the engine, obtain the oil-gas pressure difference of each cylinder of the engine;

[0111] S404, if the oil-gas pressure difference of the cylinder is greater than the second preset oil-gas pressure difference of the cylinder and less than the first preset oil-gas pressure difference of the cylinder, obtain a cylinder oil-gas pressure difference correction value according to the degree of deviation between the current oil-gas pressure difference of the cylinder and the target pressure difference of the cylinder;

[0112] S405. Correct the fuel pressure of the cylinder according to the cylinder oil-gas pressure difference correction value so that the degree of deviation between the current cylinder oil-gas pressure difference and the target cylinder pressure difference is less than or equal to the cylinder oil-gas pressure difference deviation degree threshold.

[0113] When the needle valve clearance caused by the wear of the cylinder nozzle needle valve increases, it affects the oil-gas pressure difference of the current cylinder, but does not affect the oil-gas pressure difference of other cylinders. At this time, adjustments can be made for a single cylinder. When the oil-gas pressure difference of a cylinder is greater than the oil-gas pressure difference of the second preset cylinder and less than the oil-gas pressure difference of the first preset cylinder, the oil-gas pressure difference of the first preset cylinder is a dangerous value, usually a serious abnormal situation such as damage or failure, and the oil-gas pressure difference of the second preset cylinder is a warning value, usually a natural situation such as wear of the cylinder nozzle needle valve. Therefore, the fuel pressure of the cylinder is corrected within the dangerous value, so that the deviation degree of the current oil-gas pressure difference of the cylinder from the target pressure difference of the cylinder is less than or equal to the cylinder oil-gas pressure difference deviation degree threshold, which can stabilize the oil-gas pressure difference of the abnormal cylinder, while not affecting the operation of other cylinders, reducing the situation of large amount of oil in the gas path, and improving engine performance. Among them, the oil-gas pressure difference of the first preset cylinder is greater than the oil-gas pressure difference of the second preset cylinder, and its specific value can be calibrated in advance according to the actual working conditions.

[0114] In combination with the first aspect, in some embodiments provided in the present application, the fuel pressure of the cylinder is P4, the gas pressure of the cylinder is P5, the corrected fuel pressure of the cylinder is P6, the oil-gas pressure difference of the cylinder is △P3, the target pressure difference of the cylinder is △P', and the cylinder oil-gas pressure difference correction value is △P4, which satisfies:

[0115] △P3=P4-P5;

[0116] △P4=△P'-△P3;

[0117] △P'=P6-P5;

[0118] P6=P4+△P3+△P4.

[0119] Due to the abnormality of the air circuit, the air pressure is difficult to adjust. The oil pressure difference of the cylinder can be controlled within the appropriate range by correcting the oil pressure.

[0120] Second, as Figure 7 As shown, the present application provides a device for confirming abnormal gas pressure in a gas path of a dual-fuel nozzle, comprising:

[0121] A first acquisition unit, used to acquire the current oil-gas pressure difference of the engine;

[0122] a second acquisition unit, configured to acquire the speed roughness of each cylinder of the engine if the current oil-gas pressure difference of the engine is greater than a first preset oil-gas pressure difference of the engine; and

[0123] The execution unit is used to determine the cylinder position with abnormal air pressure according to the deviation between the speed roughness of each cylinder of the engine and the speed roughness threshold.

[0124] By obtaining the speed roughness of each cylinder, according to the deviation between the speed roughness of each cylinder of the engine and the speed roughness threshold, the position of the cylinder with abnormal air pressure is determined, and the abnormal cylinder is locked to improve the reliability of the engine. The speed roughness of the cylinder is based on the crankshaft angular acceleration corresponding to the power stroke of each cylinder obtained based on the engine crankshaft speed signal. According to the deviation value of the deviation between the crankshaft angular acceleration corresponding to the power stroke of each cylinder and the speed roughness threshold, it can be judged whether the current cylinder has abnormal air pressure.

[0125] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, device, product or equipment that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or equipment. The terms "first", "second" and "third" are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit "first", "second" and "third" to be different types.

[0126] In the description of the embodiments of the present application, "exemplary", "for example" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary", "for example" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "for example" or "for example" is intended to present related concepts in a specific way.

[0127] In the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; the “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, “multiple” refers to two or more than two.

[0128] In some processes described in the embodiments of the present application, multiple operations or steps that appear in a specific order are included, but it should be understood that these operations or steps may not be executed in the order in which they appear in the embodiments of the present application or in parallel, and the sequence number of the operation is only used to distinguish the different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed in sequence or in parallel, and these operations or steps may be combined.

[0129] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, disk, CD) as described above, and includes a number of instructions for a terminal device to execute the methods described in each embodiment of the present application.

[0130] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for confirming abnormal gas pressure in a dual-fuel nozzle, characterized in that: The following steps are involved: Get the current oil-gas pressure difference of the engine; If the current oil-gas pressure difference of the engine is greater than the first preset oil-gas pressure difference of the engine, the speed roughness of each cylinder of the engine is obtained; The position of the cylinder with abnormal air pressure is determined according to the deviation between the speed roughness of each cylinder of the engine and the speed roughness threshold.

2. The method for confirming abnormal gas pressure in the gas path of a dual-fuel nozzle according to claim 1, characterized in that: Determining the cylinder position with abnormal air pressure according to the deviation between the speed roughness of each cylinder of the engine and the speed roughness threshold comprises: Comparing the absolute value of the difference between the speed roughness of each cylinder and the speed roughness of a preset cylinder with the size of the preset difference; If the absolute value of the difference between the rotational speed roughness in the cylinder and the rotational speed roughness of the preset cylinder is greater than the preset difference, it is determined that the cylinder is a cylinder with abnormal gas path pressure.

3. The method for confirming abnormal gas pressure in the gas path of a dual-fuel nozzle according to claim 2, characterized in that: If the absolute value of the difference between the speed roughness in the cylinder and the speed roughness of the preset cylinder is greater than the preset difference, then judging that the cylinder is a cylinder with abnormal gas path pressure includes: If the absolute value of the difference between the speed roughness of the cylinder and the speed roughness of the preset cylinder is greater than the preset difference, compare the ratio of the speed roughness of the cylinder to the speed roughness of other normal cylinders; If the ratio of the speed roughness of the cylinder to the speed roughness of other normal cylinders exceeds a preset ratio range, the cylinder is determined to be a cylinder with abnormal gas path pressure.

4. The method for confirming abnormal gas pressure in the gas path of a dual-fuel nozzle according to claim 1, characterized in that: If the current oil-gas pressure difference of the engine is greater than the first preset oil-gas pressure difference of the engine, the speed roughness of each cylinder of the engine is obtained, and the speed roughness of the cylinder is α1, which satisfies: α1=d(2π*N) / dt; Wherein, N is the engine speed; t is time.

5. The method for confirming abnormal gas pressure in the gas path of a dual-fuel nozzle according to claim 1, characterized in that: After obtaining the current oil-gas pressure difference of the engine, the method further includes: If the engine's oil-gas pressure difference is greater than the second preset engine's oil-gas pressure difference and less than the first preset engine's oil-gas pressure difference, adjust the fuel pressure so that the degree of deviation between the oil-gas pressure difference and the target pressure difference is less than or equal to the oil-gas pressure difference deviation degree threshold.

6. The method for confirming abnormal gas pressure in the gas path of a dual-fuel nozzle according to claim 5, characterized in that: If the fuel-gas pressure difference of the engine is greater than the second preset fuel-gas pressure difference of the engine and less than the first preset fuel-gas pressure difference of the engine, adjusting the fuel pressure so that the degree of deviation between the fuel-gas pressure difference and the target pressure difference is less than or equal to the fuel-gas pressure difference deviation degree threshold comprises: If the engine oil-gas pressure difference is greater than the second preset engine oil-gas pressure difference and less than the first preset engine oil-gas pressure difference, obtaining an engine oil-gas pressure difference correction value according to the degree of deviation between the current engine oil-gas pressure difference and the target engine pressure difference; The fuel pressure at the fuel inlet of the engine is corrected according to the engine oil-gas pressure difference correction value so that the degree of deviation between the current engine oil-gas pressure difference and the target pressure difference of the engine is less than or equal to the engine oil-gas pressure difference deviation degree threshold.

7. The method for confirming abnormal gas pressure in the gas path of a dual-fuel nozzle according to claim 6, characterized in that: The actual fuel pressure at the fuel inlet of the engine is P1, the actual fuel pressure at the outlet of the engine oil-gas balance valve is P2, the corrected fuel pressure of the engine is P3, the current oil-gas pressure difference of the engine is △P1, the target pressure difference of the engine is △P, and the correction value of the oil-gas pressure difference of the engine is △P2, which satisfies: △P1=P1-P2; △P2=△P-△P1; △P=P3-P2; P3=P1+△P1+△P2.

8. The method for confirming abnormal gas pressure in the gas path of a dual-fuel nozzle according to claim 5, characterized in that: If the fuel-gas pressure difference of the engine is greater than the second preset fuel-gas pressure difference of the engine and less than the first preset fuel-gas pressure difference of the engine, adjusting the fuel pressure so that the degree of deviation between the fuel-gas pressure difference and the target pressure difference is less than or equal to the fuel-gas pressure difference deviation degree threshold comprises: If the oil-gas pressure difference of the engine is greater than the second preset oil-gas pressure difference of the engine and less than the first preset oil-gas pressure difference of the engine, obtaining the oil-gas pressure difference of each cylinder of the engine; If the oil-gas pressure difference of the cylinder is greater than the second preset oil-gas pressure difference of the cylinder and less than the first preset oil-gas pressure difference of the cylinder, a cylinder oil-gas pressure difference correction value is obtained according to the degree of deviation between the current oil-gas pressure difference of the cylinder and the target pressure difference of the cylinder; The fuel pressure of the cylinder is corrected according to the cylinder oil-gas pressure difference correction value so that the deviation degree between the current oil-gas pressure difference of the cylinder and the target pressure difference of the cylinder is less than or equal to the cylinder oil-gas pressure difference deviation degree threshold.

9. The method for confirming abnormal gas pressure in the gas path of a dual-fuel nozzle according to claim 8, characterized in that: The fuel pressure of the cylinder is P4, the gas pressure of the cylinder is P5, the corrected fuel pressure of the cylinder is P6, the oil-gas pressure difference of the cylinder is △P3, the target pressure difference of the cylinder is △P', and the correction value of the oil-gas pressure difference of the cylinder is △P4, which satisfies: △P3=P4-P5; △P4=△P'-△P3; △P'=P6-P5; P6=P4+△P3+△P4.

10. A device for confirming abnormal gas pressure in a gas path of a dual-fuel nozzle, characterized in that: include: A first acquisition unit, used to acquire the current oil-gas pressure difference of the engine; a second acquisition unit, configured to acquire the speed roughness of each cylinder of the engine if the current oil-gas pressure difference of the engine is greater than a first preset oil-gas pressure difference of the engine; as well as The execution unit is used to determine the cylinder position with abnormal air pressure according to the deviation between the speed roughness of each cylinder of the engine and the speed roughness threshold.

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