Method for detecting working state of injector in high-pressure common rail multi-cylinder diesel engine bench test

Abstract

The application provides a high-pressure common rail multi-cylinder diesel engine bench test injector working state detection method, comprising: S1, obtaining the working state characteristics of the injector; S2, according to the state characteristics obtained in step S1, according to a preset troubleshooting method, troubleshooting whether there is a power supply abnormal fault, a nozzle blockage fault and a needle valve sticking and wear fault. The application has the beneficial effects that: the high-pressure common rail multi-cylinder diesel engine bench test injector working state detection method is based on a multi-channel signal fusion online detection method in the crank angle domain, which integrates electric signals, pressure signals, temperature signals and flow signals, etc., the abnormal working characteristics covered completely cover the faults of high-pressure common rail injector power supply abnormality, nozzle blockage and needle valve sticking and wear, and the signal extraction is convenient, and the abnormal working state detection of the injector is accurate.

Description

Technical Field

[0001] This invention belongs to the field of bench testing of high-pressure common rail multi-cylinder diesel engines, and in particular relates to a method for detecting the working status of injectors in bench testing of high-pressure common rail multi-cylinder diesel engines. Background Technology

[0002] The common rail injector injects high-pressure fuel into the combustion chamber at the optimal injection timing and quantity, based on control signals issued by the electronic control unit (ECU).

[0003] Existing diesel engine fault diagnosis and health management systems have the following main drawbacks:

[0004] ① Low accuracy in injector fault diagnosis: First, fault feature extraction is difficult. Damage and failure in the common rail system often occur internally, making disassembly and assembly inconvenient and on-site fault location difficult. Currently, the most successful method is pressure signal-based fault diagnosis, but the common rail system operates in a harsh environment and is susceptible to random external interference, making it difficult to detect fault symptoms in a timely manner. Furthermore, pressure signal-based fault features have high dispersion, making it difficult to extract effective fault features. Second, fault decision-making is difficult. Extensive simulation statistics show that one detection information in the fuel system covers multiple features, and each fault mode requires multiple detection information for fault location. Moreover, the fault features covered by a single signal are limited, and the fault features of a single fault mode have high dispersion, making fault features easily overlooked, resulting in difficult fault decision-making.

[0005] ② Assessing the reliability of fuel injectors is challenging: First, while high-precision fault diagnosis is crucial, improving the reliability and lifespan of high-pressure common rail injectors hinges on real-time acquisition of their health status and prediction of remaining lifespan. Second, in actual bench tests, performance degradation of high-pressure common rail injectors is often sporadic. Therefore, describing the performance degradation curve of the entire failure process from the perspective of failure modes and ensuring long-term prediction accuracy with limited historical data is extremely difficult, and online detection methods are lacking.

[0006] Therefore, this invention addresses the current lack of online detection methods for the working status of injectors in high-pressure common rail diesel engine bench tests. Taking into account the overall engine and safety emissions, it proposes an online detection method based on multi-channel signal fusion in the crankshaft angular domain. This method effectively extracts abnormal operating characteristics of the injectors and enables rapid and accurate diagnosis of high-pressure common rail injector faults in bench tests. Summary of the Invention

[0007] In view of this, the present invention aims to propose a method for detecting the operating status of injectors in high-pressure common rail multi-cylinder diesel engines on a bench test, specifically an online detection method for the operating status of injectors in high-pressure common rail multi-cylinder diesel engines, and to verify this method. The results show that the online detection method based on multi-channel signal fusion in the crankshaft angular domain can achieve accurate detection of the operating status of injectors in high-pressure common rail multi-cylinder diesel engines.

[0008] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0009] Methods for testing the working condition of injectors in high-pressure common rail multi-cylinder diesel engines on bench tests, including:

[0010] S1. Obtain the working status characteristics of the fuel injector;

[0011] S2. Based on the status characteristics obtained in step S1, check for power supply abnormality, nozzle blockage, needle valve jamming, and wear according to the preset troubleshooting method.

[0012] In step S1, the acquired working status features include:

[0013] Obtain the voltage and current values ​​of the solenoid valve in operation;

[0014] Obtain combustion pressure and exhaust temperature values ​​for in-cylinder combustion.

[0015] Obtain fuel consumption values ​​indicating whether the injection nozzle is clogged and whether the needle valve is stuck or worn;

[0016] The pre-defined troubleshooting methods include methods for determining abnormal operation of the solenoid valve coil:

[0017] The voltage and current of the solenoid valve are detected during operation. The measured values ​​and phases are compared with the normal values. If there is a difference after comparison, it is determined that the power supply to the injector solenoid valve is abnormal; otherwise, it indicates that the power supply to the solenoid valve is normal.

[0018] Furthermore, the pre-defined troubleshooting methods include methods for determining whether the nozzle is normally open or normally closed:

[0019] If there is no abnormality in the power supply to the solenoid valve, the combustion situation in the cylinder is monitored in real time by the cylinder pressure sensors and K-type thermocouple sensors arranged in each cylinder. A comprehensive comparison is needed to draw a conclusion.

[0020] If the difference between the cylinder pressure and exhaust temperature of a single cylinder and the values ​​of other cylinders exceeds a first preset threshold, then check whether the injector has a normally open or normally closed mechanical fault.

[0021] Furthermore, the pre-set troubleshooting methods include methods for judging nozzle blockage and needle valve sticking and wear: This involves directly monitoring the fuel consumption values ​​of each cylinder and the total return flow rate of the high-pressure common rail to determine whether the nozzles and needle valves of each cylinder's injectors are stuck or worn. This includes:

[0022] If the difference between the fuel consumption value of a single cylinder and the value of other cylinders exceeds the second preset threshold, and the total return flow rate is lower than the third preset threshold, it is determined that the injector nozzle of this cylinder is blocked or the needle valve is stuck.

[0023] If the difference between the fuel consumption value of a single cylinder and the values ​​of other cylinders exceeds the fourth preset threshold, and the total return oil flow rate is higher than the fifth preset threshold, it is determined that the needle valve and its guide surface are worn, and the fuel injection quantity increases.

[0024] Furthermore, this solution discloses an electronic device, including a processor and a memory connected in communication with the processor and used to store executable instructions of the processor, wherein the processor is used to execute a method for detecting the working status of injectors in a high-pressure common rail multi-cylinder diesel engine bench test.

[0025] Furthermore, this solution discloses a server, including at least one processor and a memory communicatively connected to the processor. The memory stores instructions executable by the at least one processor, which are executed by the processor to cause the at least one processor to perform a method for detecting the working status of injectors in a high-pressure common rail multi-cylinder diesel engine bench test.

[0026] Furthermore, this solution discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, implements a method for detecting the working status of injectors in a high-pressure common rail multi-cylinder diesel engine bench test.

[0027] Compared with existing technologies, the high-pressure common rail multi-cylinder diesel engine bench test injector working status detection method of the present invention has the following advantages:

[0028] The high-pressure common rail multi-cylinder diesel engine bench test injector working status detection method described in this invention integrates electrical signals, pressure signals, temperature signals, and flow signals based on the multi-channel signal fusion online detection method in the crankshaft angular domain. The abnormal working characteristics covered completely cover the power supply abnormalities, nozzle blockage, needle valve jamming, and wear faults of the high-pressure common rail injector. Moreover, the signal extraction is convenient and the abnormal working status detection of the injector is accurate. Attached Figure Description

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0030] Figure 1 This is a schematic diagram of the high-pressure common rail injector injection system according to an embodiment of the present invention.

[0031] Figure 2 This is a schematic diagram showing the high-pressure common rail injector stopping injection according to an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of signal acquisition for the online detection system for the working status of fuel injectors according to an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the online detection method for multi-channel signal fusion based on crankshaft angular domain as described in an embodiment of the present invention.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1-Return oil hole; 2-Ball valve; 3-Drain oil hole; 4-Control chamber; 5-Needle valve return spring; 6-Needle valve; 7-Accumulator chamber; 8-Injection hole; 9-High-pressure oil pipe; 10-Voltage signal; 11-Current signal; 12-Cylinder pressure measurement signal in angle region; 13-Injector; 14-Exhaust manifold temperature; 15-Common rail; 16-Flow rate value; 17-High-pressure common rail return oil; 18-Fuel consumption value. Detailed Implementation

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0037] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0038] The working principle of the high-pressure common rail injector is as follows: High-pressure fuel enters the injector through the high-pressure fuel line 9 and is divided into two parts: one part enters the accumulator chamber 7 inside the needle valve body, and the other part enters the control chamber 4. When the solenoid valve is energized, the ball valve 2 opens, and the high-pressure fuel in the control chamber flows out from the drain hole 3 and finally flows into the fuel tank through the return hole 1. The pressure in the control chamber decreases, and the force acting on the needle valve 6 decreases. When "control chamber pressure + needle valve return spring 5 pressure < accumulator chamber pressure inside the needle valve body", the needle valve opens, and the nozzle 8 begins to inject fuel. When the solenoid valve is de-energized, the ball valve closes, the pressure in the control chamber increases, and the force acting on the needle valve increases. When "control chamber pressure + needle valve return spring pressure > accumulator chamber pressure inside the needle valve body", the needle valve closes, and the nozzle stops injecting fuel. The common rail injector injects high-pressure fuel into the combustion chamber at the optimal injection timing and quantity according to the control signal issued by the electronic control unit (ECU).

[0039] The working principle of the injector can clarify the mechanism of abnormal operation of the high-pressure common rail injector: the injector is connected to the cylinder, the inside of the injector is under high pressure for a long time, and the outside of the nozzle is under high temperature and high pressure circulation for a long time. Therefore, its abnormal state usually manifests as abnormal operation of the solenoid valve coil and mechanical failure (nozzle blockage and needle valve assembly failure).

[0040] Solenoid valve coil malfunction: The solenoid valve coil is the actuator that controls the opening and closing of the fuel injector. If the power supply to the solenoid valve is abnormal, it will directly lead to abnormal fuel injection by the fuel injector.

[0041] Injector clogging: The fuel injector is connected to the cylinder. During long-term operation, incomplete combustion of the air-fuel mixture in the cylinder forms carbon deposits that clog the injector orifice. Additionally, poor fuel cleanliness can also cause injector clogging. Injector clogging not only leads to reduced fuel injection and decreased power, but also results in poor fuel atomization, incomplete combustion, and worsened emissions.

[0042] Needle valve assembly failure: The needle valve and needle valve body are precisely fitted together. When impurities or acidic substances in the fuel corrode the needle valve and cause it to stick, the effective stroke of the needle valve will decrease, the injection duration and injection quantity will decrease, and the diesel engine power will drop. In addition, the high-speed repetitive reciprocating motion of the needle valve will also cause wear between the needle valve and its guide surface, which will lead to an increase in the gap between the needle valve and the guide surface. A large amount of fuel will enter the fuel reservoir, prolonging the needle valve opening and injection duration, increasing the injection quantity, and resulting in insufficient air content, which in turn leads to poor combustion quality and deterioration of emissions.

[0043] Existing diesel engine fault diagnosis and health management systems have the following main drawbacks:

[0044] ① Low accuracy in injector fault diagnosis: First, fault feature extraction is difficult. Damage and failure in the common rail system often occur internally, making disassembly and assembly inconvenient and on-site fault location difficult. Currently, the most successful method is pressure signal-based fault diagnosis, but the common rail system operates in a harsh environment and is susceptible to random external interference, making it difficult to detect fault symptoms in a timely manner. Furthermore, pressure signal-based fault features have high dispersion, making it difficult to extract effective fault features. Second, fault decision-making is difficult. Extensive simulation statistics show that one detection information in the fuel system covers multiple features, and each fault mode requires multiple detection information for fault location. Moreover, the fault features covered by a single signal are limited, and the fault features of a single fault mode have high dispersion, making fault features easily overlooked, resulting in difficult fault decision-making.

[0045] ② Assessing the reliability of fuel injectors is challenging: First, while high-precision fault diagnosis is crucial, improving the reliability and lifespan of high-pressure common rail injectors hinges on real-time acquisition of their health status and prediction of remaining lifespan. Second, in actual bench tests, performance degradation of high-pressure common rail injectors is often sporadic. Therefore, describing the performance degradation curve of the entire failure process from the perspective of failure modes and ensuring long-term prediction accuracy with limited historical data is extremely difficult, and online detection methods are lacking.

[0046] Therefore, this invention addresses the current lack of online detection methods for the working status of injectors in high-pressure common rail diesel engine bench tests. Taking into account the overall engine and safety emissions, it proposes an online detection method based on multi-channel signal fusion in the crankshaft angular domain. This method effectively extracts abnormal operating characteristics of the injectors and enables rapid and accurate diagnosis of high-pressure common rail injector faults in bench tests.

[0047] The online detection method based on multi-channel signal fusion in the crankshaft angular domain is used to detect abnormal working conditions of high-pressure common rail injectors. It mainly covers directly measured electrical signals, pressure signals, temperature signals, and flow signals. High-pressure fuel is distributed to each cylinder injector via the common rail 6. Taking a single injector as an example, the working state characteristics of injector 4 are extracted according to the working principle of the high-pressure common rail diesel engine. These include voltage (1) and current signals (2) to detect whether the solenoid valve power supply is normal, cylinder pressure measurement signals (3) under the angular domain to detect whether the high-pressure fuel injection timing and injection quantity are normal, exhaust manifold temperature (5) measured by a K-type thermocouple sensor, and fuel consumption value (9) and high-pressure common rail return flow value (7) measured by a mass fuel consumption meter. Specifically: 1. Voltage and current values ​​used to detect the working state of the solenoid valve; 2. Combustion pressure and exhaust temperature values ​​used to detect the combustion situation in the cylinder; 3. Fuel consumption value used to detect whether the injection orifice is blocked. The fault characteristics covered by these three signals completely encompass power supply abnormalities, nozzle blockages, needle valve sticking, and wear faults in high-pressure common rail injectors. Furthermore, the signals are easy to extract and provide accurate fault location for injectors.

[0048] 1. Method for judging abnormal operation of solenoid valve coil: By detecting the voltage (1) and current (2) of the solenoid valve in operation, it is possible to effectively judge whether the power supply of the injector solenoid valve is normal. The voltage and current are directly measured with a clamp multimeter. If the measured value and phase are different from the normal value, it is judged that the solenoid valve is abnormal.

[0049] 2. Method for judging nozzle blockage: If the voltage and current measured by the clamp multimeter are normal, it indicates that there is no abnormality in the power supply of the solenoid valve. The combustion in the cylinder can be monitored in real time by the cylinder pressure sensor and K-type thermocouple sensor arranged in each cylinder. However, when extracting such signals, it is necessary to make a comprehensive comparison to draw conclusions. If the cylinder pressure and exhaust temperature values ​​of a single cylinder are significantly different from those of other cylinders, it can be checked whether the injector is a normally open or normally closed mechanical fault.

[0050] 3. Method for troubleshooting needle valve assembly faults: The nozzle is the most important actuator of the fuel injector. By directly monitoring the fuel consumption value of each cylinder and the total return flow rate of the high-pressure common rail, it can be determined whether the nozzle of each cylinder's fuel injector is blocked. If the fuel consumption value of a single cylinder is significantly lower than that of other cylinders, and the total return flow rate is significantly lower, it can be considered that the nozzle of this cylinder's fuel injector is blocked or the needle valve is stuck. If the fuel consumption value of a single cylinder is significantly higher than that of other cylinders, and the return flow rate is significantly higher, it can be considered that the needle valve and its guide surface are worn, resulting in an increase in the amount of fuel injected.

[0051] Those skilled in the art will recognize that the units and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0052] In the several embodiments provided in this application, it should be understood that the disclosed methods and systems can be implemented in other ways. For example, the division of units described above is merely a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. The aforementioned units may or may not be physically separated. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments of the present invention according to actual needs.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for detecting the working status of injectors in a high-pressure common rail multi-cylinder diesel engine bench test, characterized in that, include: S1. Obtain the working status characteristics of the fuel injector; S2. Based on the status characteristics obtained in step S1, check whether there are power supply abnormality faults, nozzle blockage faults, needle valve jamming, or wear faults according to the preset troubleshooting method. In step S1, the acquired working status features include: Obtain the voltage and current values ​​of the solenoid valve in operation; Obtain combustion pressure and exhaust temperature values ​​for in-cylinder combustion. Obtain fuel consumption values ​​for whether the injection nozzle is blocked and whether the needle valve is stuck or worn; In step S2, the preset troubleshooting methods include a method for judging abnormal operation of the solenoid valve coil: The voltage and current of the solenoid valve are detected during operation. The measured values ​​and phases are compared with the normal values. If there is a difference after comparison, it is determined that the power supply of the injector solenoid valve is abnormal. Otherwise, it indicates that the power supply of the solenoid valve is normal. The pre-defined troubleshooting methods include methods for determining whether the nozzle is normally open or normally closed: If there is no abnormality in the power supply to the solenoid valve, the combustion situation in the cylinder is monitored in real time by the cylinder pressure sensors and K-type thermocouple sensors arranged in each cylinder. A comprehensive comparison is needed to draw a conclusion. If the difference between the cylinder pressure and exhaust temperature of a single cylinder and the values ​​of other cylinders exceeds the first preset threshold, check whether the injector has a normally open or normally closed mechanical fault. Pre-defined troubleshooting methods include methods for checking nozzle blockage, needle valve sticking, and wear: This involves directly monitoring the fuel consumption values ​​of each cylinder and the total return flow rate of the high-pressure common rail to determine if the injector nozzles of each cylinder are blocked, including: If the difference between the fuel consumption value of a single cylinder and the value of other cylinders exceeds the second preset threshold, and the total return flow rate is lower than the third preset threshold, it is determined that the injector nozzle of this cylinder is blocked or the needle valve is stuck. If the difference between the fuel consumption value of a single cylinder and the values ​​of other cylinders exceeds the fourth preset threshold, and the total return oil flow rate is higher than the fifth preset threshold, it is determined that the needle valve and its guide surface are worn, and the fuel injection quantity increases.

2. An electronic device, comprising a processor and a memory communicatively connected to the processor and used for storing processor-executable instructions, characterized in that: The processor is used to execute the high-pressure common rail multi-cylinder diesel engine bench test injector working status detection method as described in claim 1.

3. A server, characterized in that: It includes at least one processor and a memory communicatively connected to the processor, the memory storing instructions executable by the at least one processor, the instructions being executed by the processor to cause the at least one processor to perform the high-pressure common rail multi-cylinder diesel engine bench test injector operating status detection method as described in claim 1.

4. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by the processor, it implements the method for detecting the working status of injectors in a high-pressure common rail multi-cylinder diesel engine bench test as described in claim 1.

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