Common rail system diagnostic method, diagnostic device, common rail system, engine, computer readable medium, and program product

Abstract

The invention provides a common rail system diagnosis method and device, a common rail system, an engine, a computer readable medium and a program product. The diagnosis method comprises the steps that the exhaust temperature of an air cylinder is obtained; internal pressure of the common rail pipe is obtained; obtaining the rear-end pressure of the flow-limiting valve matched with the air cylinder; and if the exhaust temperature is smaller than the exhaust temperature threshold value, the internal pressure of the common rail pipe is larger than the internal pressure threshold value of the common rail pipe, and the rear-end pressure of the flow-limiting valve is smaller than the rear-end pressure threshold value of the flow-limiting valve, it is judged that the working state of the flow-limiting valve matched with the air cylinder is closed. According to the diagnosis method, the working state information of the flow-limiting valve in the common rail system can be determined, the diagnosis method is suitable for being carried out in the actual operation process of an engine, the misjudgment risk is low, the working state information of the flow-limiting valve can be used for engine fault positioning, and the manual work amount, time, cost and the like of fault maintenance can be reduced.

Description

Technical Field

[0001] The present application relates to a common rail system diagnosis method, a diagnosis device, a common rail system, an engine, a computer-readable medium, and a program product. Background Art

[0002] The common-rail system is widely used due to its high efficiency in reducing diesel engine emissions. To ensure the reliability of the common-rail system, a flow limiting valve is typically installed between the high-pressure common rail pipe and the electronically controlled fuel injector 40. If the injector 40 becomes stuck or otherwise malfunctions, the flow limiting valve closes, cutting off the fuel flow to the injector 40. This prevents excessive fuel from entering the cylinder, preventing engine loss of control and protecting personnel and equipment.

[0003] Currently, testing of the flow restrictor valve in a common rail system primarily focuses on its closing flow characteristics and other performance characteristics, often requiring disassembly of engine components and testing under test conditions. Consequently, conventional fault diagnosis and repair procedures require disassembly of engine components after a fault occurs, and testing to determine the operating performance of the flow restrictor valve. This indirectly infers its actual operating status and impact during operation, and serves as a basis for fault location. This results in extensive manual labor, is time-consuming, and expensive. Furthermore, there is a need in the art to further develop methods for testing the operating status of the flow restrictor valve in a common rail system that are applicable to actual operating conditions.

[0004] In view of this, the inventors of the present application propose a common rail system diagnostic method, a diagnostic device, and a common rail system to solve at least one or a combination of the above technical problems. Summary of the Invention

[0005] The purpose of this application is to provide a common rail system diagnosis method.

[0006] Another object of the present application is to provide a common rail system diagnostic device.

[0007] Another object of the present application is to provide a common rail system.

[0008] Another object of the present application is to provide an engine.

[0009] Another object of the present application is to provide a computer-readable medium.

[0010] Another object of the present application is to provide a computer program product.

[0011] A common rail system diagnostic method according to the first aspect of the present application includes:

[0012] Get the exhaust temperature of the cylinder;

[0013] Obtain the internal pressure of the common rail pipe;

[0014] Obtaining the pressure at the rear end of the flow limiting valve matching the cylinder;

[0015] If the exhaust temperature is lower than the exhaust temperature threshold, the common rail internal pressure is higher than the common rail internal pressure threshold, and the pressure at the rear end of the flow limiting valve is lower than the pressure at the rear end of the flow limiting valve threshold, it is determined that the working state of the flow limiting valve matching the cylinder is closed.

[0016] The diagnostic method described above can determine the working status information of the flow limiting valve in the common rail system. In other words, it can determine that the flow limiting valve is in a closed working state. The principle is: when the cylinder exhaust temperature is lower than the exhaust temperature threshold, possible situations include injector failure or flow limiting valve closure, which affects the injection and combustion process and reduces the heat released, or the temperature measuring equipment used to measure the cylinder exhaust temperature fails, resulting in the obtained cylinder exhaust temperature being incorrect, etc., and it is necessary to combine other criteria for diagnosis; when the internal pressure of the common rail pipe is higher than the internal pressure threshold of the common rail pipe, possible situations include injector failure or flow limiting valve closure, which causes water hammer effect inside the common rail pipe and rail pressure surge; through dual verification based on exhaust temperature and internal pressure of the common rail pipe, the possibility of temperature and rail pressure measuring equipment failure is eliminated, the risk of misjudgment is reduced, and the judgment conclusion is improved. reliability; if the above two conditions are met, the possible situation is determined to be injector failure or flow limiting valve closure, and then if the pressure at the rear end of the flow limiting valve is less than the valve rear pressure threshold, it means that the fuel has not passed through the flow limiting valve, resulting in a decrease in the pressure at the rear end of the flow limiting valve, and thus it is determined that the working state of the flow limiting valve in this case is closed; the exhaust temperature of the cylinder, the internal pressure of the common rail pipe, and the pressure at the rear end of the flow limiting valve are all information that can be obtained during actual operation, so the method is suitable for implementation during the actual operation of the engine; the working state of the flow limiting valve can be obtained by using the method, and then the fault location can be performed based on this to ensure stable and reliable operation of the engine; compared with traditional diagnostic methods, the working state information of the flow limiting valve can be obtained without disassembling components after a fault occurs and performing tests on a test bench, which is conducive to reducing the manual workload, time and cost of fault repair.

[0017] In one or more embodiments of the diagnostic method, the method further comprises:

[0018] The exhaust temperature of each of the plurality of cylinders is obtained, a fault location is determined based on the cylinders whose exhaust temperature is less than the exhaust temperature threshold, and the pressure at the rear end of the flow limiting valve at the fault location is obtained using the same pressure measuring device.

[0019] In one or more embodiments of the diagnostic method, the method further comprises:

[0020] During the actual operation of the common rail system, the exhaust gas temperature and the internal pressure of the common rail pipe are monitored in real time, and the following steps are performed:

[0021] S1. Repeatedly determine whether the exhaust temperature of the cylinder is less than the exhaust temperature threshold until the determination result is yes, and then proceed to step S2;

[0022] S2. Determine whether the internal pressure of the common rail pipe is greater than the internal pressure threshold of the common rail pipe;

[0023] If yes, proceed to step S3;

[0024] If not, it is determined to be a first fault state;

[0025] S3, obtaining the pressure at the rear end of the flow limiting valve matching the cylinder, and determining whether the pressure at the rear end of the flow limiting valve is less than a pressure threshold at the rear end of the flow limiting valve;

[0026] If yes, it is determined that the working state of the flow limiting valve is closed;

[0027] If not, it is determined to be the second fault state.

[0028] In one or more embodiments of the diagnostic method, step S1 further includes: if the exhaust temperature is greater than or equal to the exhaust temperature threshold, determining that the operating state of the flow limiting valve is open.

[0029] In one or more embodiments of the diagnostic method, the method further comprises:

[0030] If it is determined to be the first fault state, then performing temperature acquisition module fault detection; and /

[0031] or,

[0032] If it is determined to be the second fault state, injector fault detection is performed.

[0033] In one or more embodiments of the diagnostic method, the method further comprises:

[0034] Outputting an indication signal according to the diagnosis result; and / or using a non-contact pressure sensor to obtain the pressure at the rear end of the flow limiting valve.

[0035] According to a second aspect of the present application, a diagnostic device for a common rail system includes: a memory for storing instructions executable by the processor; and a processor for executing the instructions to implement the diagnostic method described above.

[0036] In one or more embodiments of the diagnostic device, it further includes: a temperature acquisition module for obtaining the cylinder exhaust temperature; a first pressure acquisition module for obtaining the internal pressure of the common rail pipe; and a second pressure acquisition module for obtaining the rear end pressure of the flow limiting valve.

[0037] In one or more embodiments of the diagnostic device, the second pressure acquisition module is configured with a non-contact pressure sensor.

[0038] In one or more embodiments of the diagnostic device, it further includes: a signal indicator for outputting an indication signal according to the diagnostic result.

[0039] According to a third aspect of the present application, a common rail system includes: a common rail system diagnostic device, and a common rail pipe, a flow limiting valve, and an injector connected in sequence; the common rail system diagnostic device is used to implement the diagnostic method as described above; the injector is connected to a cylinder.

[0040] According to a fourth aspect of the present application, an engine includes: a common rail system and a cylinder; wherein the common rail system includes a common rail system diagnostic device, and a common rail pipe, a flow limiting valve, and an injector connected in sequence; the common rail system diagnostic device is used to implement the diagnostic method described above; and the injector is connected to the cylinder.

[0041] According to a fifth aspect of the present application, a computer-readable medium has a computer program thereon, and the program is executed by a processor to implement the above-mentioned diagnostic method.

[0042] A computer program product according to a sixth aspect of the present application includes a computer program, which implements the above-mentioned diagnostic method when executed by a processor. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The above and other features, properties and advantages of the present application will become more apparent through the following description in conjunction with the accompanying drawings and embodiments. In the accompanying drawings, the same reference numerals always represent the same features. It should be noted that these drawings are only for illustration and are not drawn to scale. They should not be used to limit the actual scope of protection claimed in this application. Among them:

[0044] Figure 1 Schematic diagram of the common rail system and the common rail system flow limiting valve diagnostic device according to an embodiment of the present application.

[0045] Figure 2 Schematic diagram of the structure of a common rail system flow limiting valve diagnostic device according to an embodiment of the present application.

[0046] Figure 3 1 is a flow chart of a common rail system flow limiting valve diagnosis method according to an embodiment of the present application.

[0047] Figure 4 Schematic diagram of the pressure change inside the common rail pipe after the flow limiting valve is closed according to an embodiment of the present application.

[0048] Description of reference numerals:

[0049] 1. Common rail system;

[0050] 10. Common rail system diagnostic device; 11. Temperature acquisition module; 12. First pressure acquisition module; 13. Second pressure acquisition module; 14. Memory; 15. Processor; 16. Signal indicator;

[0051] 20. Common rail pipe; 30. Flow limiting valve; 40. Fuel injector;

[0052] 51. Fuel tank; 52. Coarse filter; 53. Low-pressure oil pump; 54. Fine filter; 55. High-pressure oil pump; 56. Distribution valve; 57. Pressure-limiting valve;

[0053] 2. Cylinder.

[0054] 100. Engine. DETAILED DESCRIPTION

[0055] Reference will now be made in detail to the various embodiments of the present application, examples of which are shown in the accompanying drawings and described below. Although the present application will be described in conjunction with the exemplary embodiments, it should be appreciated that this specification is not intended to limit the present application to those exemplary embodiments. On the contrary, the present application is intended to cover not only these exemplary embodiments, but also various alternative forms, modifications, equivalent forms, and other embodiments that may be included within the spirit and scope of the present application as defined by the appended claims.

[0056] This application uses specific terms to describe the embodiments of this application. For example, "one embodiment" and / or "an embodiment" refer to a feature, structure, or characteristic associated with at least one embodiment of this application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" mentioned twice or more in different places in this application does not necessarily refer to the same embodiment; and certain features, structures, or characteristics in one or more embodiments of this application may be appropriately combined. In this application, the terms "first," "second," etc. are used solely to distinguish descriptions and should not be understood to indicate or imply positional relationships or rankings of importance. In the subsequent description, unless otherwise expressly specified or limited, the directions or positional relationships indicated by "upper," "lower," "left," "right," "front," "back," or other directional terms are based on the directions or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this application and simplify the description. They do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and / or implemented in a specific orientation, and therefore should not be understood to limit this application. In the following description, unless otherwise specified or limited, the terms "connected" and "connected" should be understood in a broad sense; for example, they can refer to direct connection or indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0057] This application uses flowcharts to illustrate the operations performed according to the embodiments of this application. It should be appreciated that, depending on the actual situation, the steps do not necessarily need to be performed in the order shown in the diagrams, and other operations may be added to these processes, or one or more steps may be removed from these processes.

[0058] It can be understood that the common rail system diagnostic method, diagnostic device, and common rail system provided in the present application are applicable to ship engines, but are not limited thereto. They can also be applied to other applicable occasions where the working status of the flow limiting valve in the common rail system needs to be detected, such as vehicles, engineering machinery engines, fuel-fired power generation equipment, etc.

[0059] like Figure 1 As shown, taking a common rail system of a marine diesel engine as an example, the common rail system 1 includes: a common rail pipe 20; a plurality of matching flow limiting valves 30 and a plurality of injectors 40, which are arranged on the common rail pipe 20; the plurality of injectors 40 are matched and connected to a plurality of cylinders 2; the common rail pipe 20, the flow limiting valve 30, the injectors 40, and the cylinders 2 are connected in sequence; the flow limiting valve 30 is located between the common rail pipe 20 and the injectors 40, and is used to cut off the oil inlet flow path to the injectors 40 when the fuel flow passing through it is too large, so as to prevent excessive fuel from being sprayed into the cylinders 2, prevent engine loss of control, and protect the safety of personnel and equipment.

[0060] like Figure 3The diagnostic method of the common rail system 1 shown includes:

[0061] Get the exhaust temperature T of cylinder 2;

[0062] Get the common rail internal pressure P A ;

[0063] Obtain the pressure P at the rear end of the flow limiting valve matching cylinder 2 B ;

[0064] If the exhaust temperature T is less than the exhaust temperature threshold T1, the internal pressure of the common rail pipe P A Greater than the common rail internal pressure threshold P1, the pressure at the rear end of the limiting valve P B If the pressure is less than the pressure threshold P2 at the rear end of the flow limiting valve, it is determined that the working state of the flow limiting valve 30 matching the cylinder 2 is closed;

[0065] Among them, the pressure at the rear end of the flow limiting valve P B Refers to the oil pressure of the fuel between the matching flow limiting valve 30 and the injector 40; the exhaust temperature threshold T1 refers to the judgment standard for judging whether the exhaust temperature T of cylinder 2 is abnormally reduced, which is determined before the relevant judgment step; when it is detected that the exhaust temperature T of cylinder 2 is less than the exhaust temperature threshold T1, it can be said that the cylinder exhaust temperature T is abnormally reduced at this time; the common rail internal pressure threshold P1 refers to the judgment standard for judging whether the internal pressure P of the common rail is abnormally reduced. A The abnormal increase judgment standard, specifically, is used to judge the abnormal surge of rail pressure due to the water hammer effect inside the common rail pipe 20, which is determined before the relevant judgment step; when the common rail pipe internal pressure P is detected A When it is greater than the common rail internal pressure threshold, it can be said that the common rail internal pressure P A Abnormal increase; the pressure threshold value P2 at the rear end of the flow limiting valve refers to the criterion for judging the abnormal decrease of the fuel pressure at the rear end of the flow limiting valve 30, that is, between the flow limiting valve 30 and the injector 40, which is determined before the relevant judgment step; when the pressure at the rear end of the pressure limiting valve P is detected B When the pressure at the rear end of the flow limiting valve is less than the pressure threshold value P2, it can be said that the pressure at the rear end of the pressure limiting valve P B Specifically, in some embodiments, at least one of the exhaust temperature threshold T1, the common rail internal pressure threshold P1, and the limiting valve rear end pressure threshold P2 may be determined based on relevant operating condition information acquired in real time when the engine is in a stable operating state.

[0066] The diagnostic method described above can determine the working state information of the flow limiting valve 30 in the common rail system 1. In other words, it can determine whether the flow limiting valve is in the closed working state. The principle is that when the cylinder exhaust temperature T is less than the exhaust temperature threshold value T1, possible situations include a failure of the injector 40 or a closure of the flow limiting valve, which affects the injection and combustion process and reduces the heat released, or a failure of the temperature measuring device used to measure the cylinder exhaust temperature T, resulting in an error in the obtained cylinder exhaust temperature T; when the internal pressure P of the common rail pipe is A When the pressure is greater than the common rail internal pressure threshold, the possible situations include the injector 40 failure or the flow limiting valve closing, which causes the water hammer effect inside the common rail 20 and the rail pressure surges; based on the exhaust temperature T and the common rail internal pressure P A Performing secondary verification is helpful to eliminate the possibility of temperature measurement equipment failure, so as to reduce the risk of misjudgment. If the above two conditions are met, it means that the possible fault situation is located in the injector 40 failure or the flow limiting valve is closed. Furthermore, if the pressure P at the rear end of the flow limiting valve is B If the pressure is less than the threshold value P2 after the valve, it means that the fuel has not passed through the flow limiting valve 30, resulting in the pressure P at the rear end of the flow limiting valve. B Decreases, thereby determining that the working state of the flow limiting valve 30 is closed; the exhaust temperature T of cylinder 2 and the internal pressure P of the common rail pipe A , pressure P at the rear end of the flow limiting valve B All of this information can be obtained during actual operation by detection equipment installed on the engine. Therefore, this method is suitable for being carried out during the actual operation of the engine and the common rail system 1 to monitor the common rail system 1 in real time. By using this method to obtain the working status of the flow limiting valve, further countermeasures can be implemented based on this information, such as fault diagnosis and adjustment of engine operating strategies such as injection strategies, so as to ensure stable and reliable operation of the engine. Compared with traditional diagnostic methods, the working status information of the flow limiting valve can be obtained without disassembling components after a fault occurs and testing under experimental conditions, which helps to reduce the manual workload, time and cost of fault repair.

[0067] In one or more embodiments, the step of determining the exhaust temperature threshold T1 may include: determining a base exhaust temperature T1 expected to be reached by a single cylinder 2 according to certain operating conditions. base , introduce the lower allowable deviation of exhaust temperature T ε (and / or correction coefficient α) to ensure that the judgment standard is reliable; according to the basic exhaust temperature T base , Exhaust temperature allowable deviation T ε and / or correction coefficient α, determine the engine exhaust temperature threshold T1. For example, determine T1 = α (T base +T ε ); where T ε The value can be T base10%, α can be 50%, T ε It may also be specifically determined based on influencing factors such as engine coolant temperature, operating condition stability, and measurement accuracy of measuring equipment, but is not limited thereto.

[0068] In one or more embodiments, the step of determining the common rail internal pressure threshold value P1 may include: determining the expected basic rail pressure fluctuation amplitude P in the common rail 20 according to certain operating conditions. base1 ; Determine the allowable deviation P of the basic rail pressure fluctuation amplitude ε1 (and / or correction coefficient α); according to the basic rail pressure fluctuation amplitude P base1 , and the allowable deviation P of the basic rail pressure fluctuation amplitude ε1 and / or correction coefficient to determine the common rail internal pressure threshold P1. For example, determine P1 = P base1 +P ε1 Among them, P ε1 It can be taken as P base1 9% of, but not limited to,

[0069] In one or more embodiments, the step of determining the pressure threshold value P2 at the rear end of the flow limiting valve may include: determining the base valve rear end pressure fluctuation amplitude P2 expected to be reached by the oil pressure between the flow limiting valve 30 and the injector 40 according to certain operating conditions; base2 , the allowable deviation P of the basic valve back pressure fluctuation amplitude ε1 (and / or correction coefficient α); according to the basic valve after the pressure fluctuation amplitude P base2 , and the allowable deviation P of the pressure fluctuation amplitude after the base rail valve ε1 and / or correction coefficient to determine the pressure threshold P2 at the rear end of the flow limiting valve. For example, P2 = P base2 +P ε2 , where P ε2 It can be taken as P base2 20% of, but not limited to.

[0070] In one or more embodiments, at least one of the exhaust temperature threshold T1, the common rail internal pressure threshold P1, and the flow limiting valve rear end pressure threshold P2 is verified and optimized by experimental testing and / or simulation calculation. Figure 4 As shown, the simulation simulates the rail pressure fluctuation caused by the water hammer effect inside the common rail pipe 20 when the limiting valve 30 is closed when the internal pressure of the common rail pipe is 160 MPa. The common rail internal pressure threshold value P1 is corrected to improve the reliability of the judgment, but the present invention is not limited to this.

[0071] In one or more embodiments, the diagnostic method may be performed during the actual operation of the common rail system 1 to monitor the working status of the flow limiting valve 30 in the common rail system 1 in real time.

[0072] In one or more embodiments, the diagnostic method further comprises:

[0073] The exhaust temperature T of each cylinder 2 is obtained, and the fault location is determined based on the cylinder 2 whose exhaust temperature T is less than the exhaust temperature threshold T1. The same pressure sensor is used to obtain the pressure behind the flow limiting valve at the fault location.

[0074] It can be understood that since the common rail system 1 includes multiple groups of flow limiting valves 30 and injectors 40, which are correspondingly connected to multiple cylinders 2, each group of flow limiting valves 30, injectors 40 and cylinders 2 may fail. Therefore, the cylinder exhaust temperature is used to locate the fault to determine the fault location to be further detected. The same pressure measuring equipment is then used to detect different fault locations, in other words, the pressure behind the flow limiting valve between different groups of flow limiting valves 30 and injectors 40 is detected. Compared with configuring sensors in each group, this is more convenient for engineering implementation and saves costs.

[0075] In one or more embodiments, a non-contact pressure sensor is used to obtain the pressure behind the flow limiting valve. A non-contact pressure sensor is a device that indirectly measures fluid pressure by detecting changes in a physical quantity caused by fluid pressure without direct contact with the fluid being measured. For example, such a device utilizes the principle of detecting changes in acoustic, optical, or electromagnetic signals. In some embodiments, the non-contact pressure sensor is configured as an ultrasonic pressure sensor.

[0076] In one or more embodiments, the diagnostic method further comprises:

[0077] During the actual operation of the common rail system 1, the exhaust temperature T and the internal pressure P of the common rail pipe are monitored in real time. A , and perform the following steps:

[0078] S1. Repeatedly determine whether the exhaust temperature T of cylinder 2 is less than the exhaust temperature threshold T1 until the determination result is yes, that is, the exhaust temperature T is less than the exhaust temperature threshold T1, and then execute step 2;

[0079] S2. Determine the internal pressure P of the common rail pipe A Is it greater than the common rail internal pressure threshold P1?

[0080] If yes, that is, the internal pressure of the common rail pipe P A If the pressure is greater than the common rail internal pressure threshold P1, step S3 is executed;

[0081] If not, that is, the internal pressure of the common rail pipe P AIf the pressure is less than or equal to the common rail internal pressure threshold P1, it is determined to be a first fault state;

[0082] S3, obtain the pressure P at the rear end of the flow limiting valve matching the cylinder 2 B , and judge the pressure P at the rear end of the flow limiting valve B Is it less than the pressure threshold P2 at the rear end of the flow limiting valve?

[0083] If yes, that is, the pressure P at the rear end of the flow limiting valve B If the pressure is less than the common rail internal pressure threshold value P2, it is determined that the working state of the flow limiting valve 30 is closed;

[0084] If not, that is, the pressure P at the rear end of the flow limiting valve B If the pressure is greater than or equal to the common rail internal pressure threshold value P2, it is determined to be a second fault state.

[0085] Diagnosis is performed under actual working conditions, which is conducive to timely obtaining diagnostic information and then responding, thereby reducing maintenance time, etc.; through step S1, it is determined that a fault has occurred, and the cylinder 2 where the fault is located and its corresponding flow limiting valve 30 and injector 40 are located; through step S2, the fault occurrence is repeatedly verified and the cause of the fault is further located, which is conducive to improving the reliability of the diagnosis result and reducing the risk of misjudgment; and, if step S2 determines that the internal pressure of the common rail pipe P A If the pressure is less than or equal to the common rail internal pressure threshold value P1, it means that there is no water hammer effect and rail pressure surge in the common rail 20 due to fuel blockage. In other words, there is no closure of the flow limiting valve 30 or failure of the injector 40, such as the injector 40 being stuck, etc., and it is determined as the first fault state to facilitate further diagnosis of the cause of the fault. By locating the cause of the fault in step S3, it can be determined whether the flow limiting valve 30 is closed, and if step 3 determines that the pressure at the rear end of the flow limiting valve P B If the pressure is greater than or equal to the common rail internal pressure threshold value P2, it means that the fuel can pass through the flow limiting valve 30. In other words, the flow limiting valve 30 is not closed. Determining it as the second fault state is conducive to further diagnosis of the cause of the fault. The use of steps S1 to S3 makes the diagnostic results more detailed and facilitates fault location.

[0086] In one or more embodiments, step S1 further includes: if the exhaust temperature T is greater than or equal to the exhaust temperature threshold T1, that is, the exhaust temperature T of the cylinder 2 meets the expected normal condition, it is presumed that the relevant components are operating normally, and then the operating state of the flow limiting valve 30 is determined to be open. This design facilitates determining the operating status of the common rail system 1 and the engine.

[0087] In one or more embodiments, when it is determined that the first fault state is in step S2 and the second fault state is in step S3 , it is determined that the operating state of the flow restriction valve 30 is open.

[0088] In one or more embodiments, different indication signals are output based on different diagnostic results. Specifically, different indication signals may be output based on a single or combined determination result of each of steps S1 to S3. For example, based on the diagnostic result of step S1, a signal indicating that the flow limiting valve 30 is open or a signal indicating that the cylinder exhaust temperature T is abnormal may be output. For another example, based on the diagnostic results of steps S1 to S3, a signal indicating at least one of: the flow limiting valve 30 is closed, the flow limiting valve 30 is open, a first fault state, and a second fault state may be output. However, the present invention is not limited thereto.

[0089] In one or more embodiments, the diagnostic method further comprises:

[0090] If the first fault state is determined, fault response measures such as temperature acquisition module 11 fault detection are executed; and / or, if the second fault state is determined, fault response measures such as injector 40 fault detection are executed. As described above, if an abnormal decrease in cylinder exhaust temperature T is detected without a pressure surge in the common rail 20, the possible cause may be a fault in the temperature acquisition module 11 causing an erroneous measurement value. Therefore, executing temperature acquisition module 11 fault detection when the first fault state is determined facilitates rapid fault troubleshooting. If an abnormal decrease in cylinder exhaust temperature T is detected, a pressure surge in the common rail 20 occurs, and there is no abnormal decrease in pressure behind the flow restrictor valve, the possible cause may be a stuck injector 40. Therefore, executing injector 40 fault detection and other measures when the second fault state is determined facilitates rapid fault troubleshooting.

[0091] like Figure 1 A common rail system diagnostic device 10 is shown, which can be used to perform diagnosis during the actual operation of the common rail system 1. The device includes: a memory 14 for storing instructions executable by the processor 15; the processor 15 is configured to execute the instructions to implement the steps of the diagnostic method described above that can be implemented by a computer program. The diagnostic method is described in detail above and will not be repeated here.

[0092] In one or more embodiments, the diagnostic device 10 further includes: a temperature acquisition module 11, for example, including a plurality of temperature sensors for obtaining the cylinder exhaust temperature T; a first pressure acquisition module 12, for example, including a plurality of rail pressure sensors for obtaining the common rail internal pressure P A The second pressure acquisition module 13, for example, includes one or more pressure sensors for obtaining the rear end pressure P of the limiting valve B; The processor 15 is connected to the temperature acquisition module 11, the first pressure acquisition module 12, and the second pressure acquisition module 13, and is used to receive signals obtained by the temperature acquisition module 11, the first pressure acquisition module 12, and the second pressure acquisition module 13, and execute instructions according to these signals to implement the steps of the diagnostic method described above that can be implemented by a computer program; the memory 14 is used to store instructions that can be executed by the processor 15.

[0093] Specifically, the temperature acquisition module 11 can be configured to include a plurality of temperature sensors, which are respectively arranged on the branch pipes of the exhaust manifold corresponding to each cylinder 2, for continuously monitoring the exhaust temperature T of the cylinder 2 during the diagnosis process; the first pressure acquisition module 12 can be configured to include a rail pressure sensor located at one end of the common rail pipe 20, for continuously monitoring the internal pressure P of the common rail pipe during the diagnosis process. A The second pressure acquisition module 13 can be configured to include a non-contact pressure sensor, such as an ultrasonic pressure sensor. The use of a non-contact pressure sensor is beneficial to structural layout. An ultrasonic pressure sensor refers to a device that can measure pressure based on the propagation characteristics of ultrasonic waves in the measured fluid (fuel). When ultrasonic waves propagate in the measured fluid, their propagation speed will be affected by the fluid pressure. By measuring the propagation time or frequency change of ultrasonic waves in the flow channel, the pressure of the measured fluid can be inferred. In one or more embodiments, the second pressure acquisition module 13 includes an ultrasonic pressure sensor that can be movably configured in the common rail system 1, and can measure the pressure P at the rear end of the flow limiting valve between the flow limiting valve 30 and the injector 40 corresponding to the cylinder 2 with an abnormally low exhaust temperature T. B using the same ultrasonic pressure sensor to detect several groups of injectors 40 and the flow limiting valve 30 in the faulty group, easy to implement engineering applications, and low cost.

[0094] like Figure 2 As shown, the above-mentioned memory 14 and processor 15 are not limited to a specific memory 14 or processor 15. For example, in some cases, the memory 14 and processor 15 can have a distributed structure. For example, they can include a memory 14 and a processor 15 located on the diagnostic device side and the backend cloud, respectively, and the above-mentioned method is implemented by the diagnostic device side and the backend cloud together. Furthermore, in the embodiment adopting a distributed structure, the specific execution terminal of each step can be adjusted according to the actual situation, and the specific scheme of each step implemented on a specific terminal should not limit the scope of protection of this application.

[0095] In one or more embodiments, the diagnostic device further includes: a signal indicator 16 connected to the processor 15, for outputting different indication signals according to different diagnostic results obtained by the processor 15; please refer to the above description for details, which will not be repeated here.

[0096] According to a third aspect of the present application, a common rail system 1 includes a common rail system diagnostic device 10; a common rail pipe 20; and a plurality of matching flow limiting valves 30 and a plurality of injectors 40, which are arranged on the common rail pipe 20; the plurality of injectors 40 are matched and connected to a plurality of cylinders 2; wherein the common rail system diagnostic device 10 includes: a temperature acquisition module 11 for obtaining the cylinder exhaust temperature T; a first pressure acquisition module 12 for obtaining the internal pressure P of the common rail pipe A ; The second pressure acquisition module 13 is used to obtain the pressure at the rear end of the flow limiting valve; the processor 15 is connected to the temperature acquisition module 11, the first pressure acquisition module 12, and the second pressure acquisition module 13, and is used to receive information obtained by the temperature acquisition module 11, the first pressure acquisition module 12, and the second pressure acquisition module 13, and execute instructions based on this information to implement the steps in the method described above that can be implemented by a computer program. Please refer to the description above for details, which will not be repeated here.

[0097] Specifically, if Figure 1 As shown, the common rail system 1 can also be configured as a dual-pump redundant structure, including a fuel tank 51, a coarse filter 52, a low-pressure fuel pump 53, a fine filter 54, and a high-pressure fuel pump 55 connected in sequence; and / or, the common rail system 1 can also be configured to include multiple high-pressure fuel pumps 55 connected in parallel to multiple common rail pipes 20 via a distribution valve 56; and / or, a pressure limiting valve 57 can also be configured on the common rail pipe 20; but the present invention is not limited thereto.

[0098] The present application also provides an engine, which includes: a common rail system 1 and a cylinder 2; wherein the common rail system 1 includes a common rail system diagnostic device 10, and a common rail pipe 20, a flow limiting valve 30, and an injector 40 connected in sequence; the common rail system diagnostic device 10 is used to implement the diagnostic method described above; the injector 40 is connected to the cylinder 2; the diagnostic method is described in detail above and will not be repeated here.

[0099] The present application also provides a computer-readable medium having a computer program thereon, which is executed by the processor 15 to implement the steps in the diagnostic method described above that can be implemented by a computer program. Please refer to the above description for details and will not be repeated here.

[0100] It is understandable that the computer-readable storage medium may also be in a system form, that is, including multiple computer-readable storage sub-media, so as to jointly implement the steps of the control method described above through multiple computer-readable storage media.

[0101] The present application also provides a computer program product, including a computer program, which, when executed by the processor 15, implements the steps in the above-mentioned diagnostic method that can be implemented by a computer program. Please refer to the above description for details, which will not be repeated here.

[0102] In summary, the common rail system diagnostic method, diagnostic device, common rail system, engine, etc. described in the above embodiments have beneficial effects including but not limited to at least one of the following:

[0103] The method can determine the working status information of the flow limiting valve in the common rail system; adopt a secondary verification based on the exhaust temperature and the internal pressure of the common rail pipe to eliminate the possibility of failure of the detection equipment, which is conducive to reducing the risk of misjudgment and improving the reliability of the diagnosis results; the exhaust temperature of the cylinder, the internal pressure of the common rail pipe, and the rear end pressure of the flow limiting valve are all information that can be obtained by the detection equipment configured in the engine during actual operation. Therefore, the diagnostic method is suitable for being carried out during the actual operation of the engine and the common rail system to monitor the common rail system in real time; the working status of the flow limiting valve is obtained by the diagnostic method, and corresponding countermeasures can be further implemented based on this, such as fault diagnosis and adjustment of engine operation strategies such as injection strategies to ensure stable and reliable operation of the engine; compared with traditional diagnostic methods, the working status information of the flow limiting valve can be obtained without disassembling components after a fault occurs and testing under test conditions, which is conducive to reducing the workload, time and cost of fault repair.

[0104] Although the present application is disclosed above with reference to preferred embodiments, this is not intended to limit the present application. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, any modifications, equivalent variations, and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application shall fall within the scope of protection defined by the claims of the present application.

[0105] The various illustrative logic modules and circuits described in conjunction with the embodiments disclosed herein may be implemented or executed using a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0106] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor so that the processor can read and write information from / to the storage medium. In an alternative, the storage medium may be integrated into the processor. The processor and storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and storage medium may reside in a user terminal as discrete components.

[0107] In one or more exemplary embodiments, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software as a computer program product, the functions may be stored on or transmitted via a computer-readable medium as one or more instructions or code. Computer-readable media include both computer storage media and communication media, including any media that facilitates the transfer of a computer program from one location to another. A storage medium may be any available medium that can be accessed by a computer. By way of example and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Any connection is also properly referred to as a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where disks typically reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

Claims

1. A common rail system diagnostic method, characterized in that: include: Get the exhaust temperature of the cylinder; Obtain the internal pressure of the common rail pipe; Obtaining the pressure at the rear end of the flow limiting valve matching the cylinder; If the exhaust temperature is lower than the exhaust temperature threshold, the common rail internal pressure is higher than the common rail internal pressure threshold, and the pressure at the rear end of the flow limiting valve is lower than the pressure at the rear end of the flow limiting valve threshold, it is determined that the working state of the flow limiting valve matching the cylinder is closed.

2. The diagnostic method according to claim 1, wherein Also includes: The exhaust temperature of each of the plurality of cylinders is obtained, a fault location is determined based on the cylinders whose exhaust temperature is less than the exhaust temperature threshold, and the pressure at the rear end of the flow limiting valve at the fault location is obtained using the same pressure measuring device.

3. The diagnostic method according to claim 1, wherein Also includes: During the actual operation of the common rail system, the exhaust gas temperature and the internal pressure of the common rail pipe are monitored in real time, and the following steps are performed: S1. Repeatedly determine whether the exhaust temperature of the cylinder is less than the exhaust temperature threshold until the determination result is yes, and then proceed to step S2; S2. Determine whether the internal pressure of the common rail pipe is greater than the internal pressure threshold of the common rail pipe; If yes, proceed to step S3; If not, it is determined to be a first fault state; S3, obtaining the pressure at the rear end of the flow limiting valve matching the cylinder, and determining whether the pressure at the rear end of the flow limiting valve is less than a pressure threshold at the rear end of the flow limiting valve; If yes, it is determined that the working state of the flow limiting valve is closed; If not, it is determined to be the second fault state.

4. The diagnostic method according to claim 3, characterized in that The step S1 further includes: if the exhaust temperature is greater than or equal to the exhaust temperature threshold, determining that the working state of the flow limiting valve is open.

5. The diagnostic method according to claim 3, characterized in that Also includes: If it is determined to be the first fault state, performing temperature acquisition module fault detection; and / or, If it is determined to be the second fault state, injector fault detection is performed.

6. The diagnostic method according to claim 1, characterized in that Also includes: Outputting an indication signal according to the diagnosis result; and / or using a non-contact pressure sensor to obtain the pressure at the rear end of the flow limiting valve.

7. A common rail system diagnostic device, characterized in that: include: a memory for storing instructions executable by the processor; A processor, configured to execute the instructions to implement the diagnostic method according to any one of claims 1 to 6.

8. The diagnostic device according to claim 7, characterized in that Also includes: A temperature acquisition module, used to obtain the cylinder exhaust temperature; A first pressure acquisition module, configured to obtain the internal pressure of the common rail pipe; The second pressure acquisition module is used to obtain the pressure at the rear end of the flow limiting valve.

9. The diagnostic device according to claim 8, characterized in that The second pressure acquisition module is configured with a non-contact pressure sensor.

10. The diagnostic device according to claim 7, wherein: Also includes: The signal indicator is used to output an indication signal according to the diagnosis result.

11. A common rail system, characterized in that: include: A common rail system diagnostic device, and a common rail pipe, a flow limiting valve, and a fuel injector connected in sequence; the common rail system diagnostic device is used to implement the diagnostic method according to any one of claims 1 to 6; the fuel injector is connected to a cylinder.

12. An engine, characterized in that: include: A common rail system and a cylinder; wherein the common rail system includes a common rail system diagnostic device, and a common rail pipe, a flow limiting valve, and an injector connected in sequence; the common rail system diagnostic device is used to implement the diagnostic method according to any one of claims 1 to 6; the injector is connected to the cylinder.

13. A computer readable medium having a computer program thereon, the program being executed by a processor to implement the diagnostic method according to any one of claims 1 to 6.

14. A computer program product comprising a computer program, wherein when the computer program is executed by a processor, the computer program implements the diagnostic method according to any one of claims 1 to 6.

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