Sequential turbocharging control valve fault diagnosis method and system

Abstract

The present application relates to a method and system for diagnosing faults of sequential turbocharging control valves of a diesel engine, obtaining hydraulic oil pressure data for driving the sequential turbocharging control valves during operation of the diesel engine; if the hydraulic oil pressure changes more than a first threshold value for one time within a set time period, the corresponding sequential turbocharging control valve has a fault; obtaining rotational speed data of each turbocharger, extracting the rotational speed of the controlled turbocharger and the rotational speed of the commonly used turbocharger, and using (rotational speed of controlled turbocharger-rotational speed of commonly used turbocharger) / rotational speed of commonly used turbocharger to obtain the turbocharger rotational speed deviation percentage; when the turbocharger rotational speed deviation percentage corresponding to the faulty sequential turbocharging control valve is greater than a second threshold value, the intake valve of the corresponding sequential turbocharging control valve has a jamming fault, and when the turbocharger rotational speed deviation percentage is less than a third threshold value, the exhaust valve of the corresponding sequential turbocharging control valve has a jamming fault. By reading and analyzing the turbocharger rotational speed and the hydraulic oil pressure change, the jamming fault of the corresponding control valve is diagnosed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of engine control technology, in particular to a sequential turbo charging control valve fault diagnosis method and system. BACKGROUND

[0002] The statements in this section merely provide background information related to the present application and do not necessarily constitute the prior art.

[0003] The sequential turbo charging (STC) technology on the diesel engine refers to a turbocharging system composed of two or more than two turbochargers in parallel, when running, according to different diesel engine operating condition requirements, the turbochargers are sequentially put into operation in a certain order, so that the diesel engine can better cope with the required operating conditions.

[0004] The sequential turbo charging control valve is a component in the sequential turbo charging system for controlling the on-off function of the turbocharger gas path, which can be divided into "exhaust valve" installed at the outlet of the compressor and "intake valve" installed at the inlet of the turbine, the two valves are collectively referred to as sequential turbo charging control valve.

[0005] Due to the complex structure of the sequential turbo charging system, it involves multiple turbochargers and corresponding control valves, making it difficult to accurately locate the position of the fault when a fault occurs, especially for the sequential turbo charging control valve, when in action, by opening and closing the gas path, the working state of the turbocharger is controlled, the existing technology checks by disassembling the control, which is time-consuming and laborious. SUMMARY

[0006] In order to solve the technical problems existing in the background art, the present application provides a diesel engine sequential turbo charging control valve fault diagnosis method and system, by reading and analyzing the turbocharger speed and hydraulic oil pressure change, setting the sequential turbo charging control valve sticking alarm limit value, diagnosing the fault of the sequential turbo charging control valve sticking.

[0007] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0008] The first aspect of the present application provides a diesel engine sequential turbo charging control valve fault diagnosis method, comprising the following steps:

[0009] Obtain the hydraulic oil pressure data for driving the sequential turbo charging control valve during the operation of the diesel engine;

[0010] If the hydraulic oil pressure changes more than 1 times within a set time period, the corresponding sequential turbo charging control valve has a fault;

[0011] The rotational speed data of each supercharger is acquired, and the controlled supercharger rotational speed and the common supercharger rotational speed are extracted, and the supercharger rotational speed deviation percentage is obtained by using (controlled supercharger rotational speed-common supercharger rotational speed) / common supercharger rotational speed.

[0012] When the supercharger rotational speed deviation percentage corresponding to the faulty sequential supercharging control valve is greater than the second threshold value, the intake valve of the corresponding sequential supercharging control valve has a sticking fault, and when the supercharger rotational speed deviation percentage is less than the third threshold value, the exhaust valve of the corresponding sequential supercharging control valve has a sticking fault.

[0013] Further, the diesel engine is equipped with multiple groups of superchargers, which are divided into common superchargers and controlled superchargers.

[0014] Further, the common superchargers are always in working state with the operation of the diesel engine, and the remaining superchargers are controlled superchargers, which are switched into working state according to the load change of the diesel engine.

[0015] Further, the sequential supercharging control valve has a group of arranged intake valves and exhaust valves, each group of intake valves and exhaust valves corresponding to a supercharger and being used to control the intake and exhaust of the supercharger, respectively.

[0016] Further, within a set time period, if the hydraulic oil pressure changes more than the first threshold value for 1 time, the corresponding sequential supercharging control valve has a fault, including the following steps:

[0017] Within the first set time period, when the pressure of the hydraulic oil changes more than the first threshold value, it is considered that a pressure fluctuation occurs, and it is judged as a sequential supercharging switching process;

[0018] The number of pressure fluctuations of the hydraulic oil within a second set time period is acquired;

[0019] When the number of pressure fluctuations is 1, the corresponding sequential supercharging control valve has a fault.

[0020] Further, within a set time period, if the hydraulic oil pressure changes more than the first threshold value for 1 time, the corresponding sequential supercharging control valve has a fault, and further including the following steps:

[0021] When the number of pressure fluctuations is 2, the corresponding sequential supercharging control valve operates normally.

[0022] Further, when the sequential supercharging control valve operates normally and is switched into working state, the exhaust valve acts before the intake valve.

[0023] Further, A is set as the supercharger rotational speed deviation percentage, that is, A=(controlled supercharger rotational speed-common supercharger rotational speed) / common supercharger rotational speed.

[0024] Further, when A is greater than the second threshold value, it is determined that the supercharger speed positive deviation is too large, the intake valve corresponding to the controlled supercharger is stuck, and corresponding reminder information or early warning information is reported;

[0025] When A is less than the third threshold value, it is determined that the supercharger speed negative deviation is too large, the exhaust valve corresponding to the controlled supercharger is stuck, and corresponding reminder information or early warning information is reported.

[0026] The second aspect of the present application provides a system for implementing the above-mentioned diesel engine sequential supercharging control valve fault diagnosis method, comprising:

[0027] The data acquisition unit is configured to obtain hydraulic oil pressure data for driving the sequential supercharging control valve to act and the speed data of each supercharger during diesel engine operation;

[0028] The data processing unit is configured to, within a set time period, if the number of times that the hydraulic oil pressure changes by more than the first threshold value is 1, the corresponding sequential supercharging control valve is faulty.

[0029] The controlled supercharger speed and the commonly used supercharger speed are extracted, and the supercharger speed deviation percentage is obtained by using: (controlled supercharger speed - commonly used supercharger speed) / commonly used supercharger speed;

[0030] When the supercharger speed deviation percentage of the supercharger corresponding to the faulty sequential supercharging control valve is greater than the second threshold value, the intake valve in the corresponding sequential supercharging control valve is stuck, and when the supercharger speed deviation percentage is less than the third threshold value, the exhaust valve in the corresponding sequential supercharging control valve is stuck.

[0031] The diagnosis and warning unit is configured to, when the intake valve or the exhaust valve in the sequential supercharging control valve is stuck, report corresponding reminder information or early warning information.

[0032] Compared with the prior art, the above one or more technical solutions have the following beneficial effects:

[0033] By extracting the hydraulic oil pressure reflecting the action of the sequential supercharging control valve and the speed of each supercharger in the operation data of the diesel engine as the judgment data, using the feature that there are two control valve action processes when the sequential supercharging intervention works as the judgment basis, and by analyzing the characteristics of the obtained data curve, the sequential supercharging control valve with stuck fault is located, it is distinguished whether the intake valve or the exhaust valve is faulty, and corresponding reminders are issued, so that the engine operation fault can be located in time and accurately, and the next step of disposal can be helped to the maintenance personnel. BRIEF DESCRIPTION OF DRAWINGS

[0034] The accompanying drawings, which form a part of this specification, are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification. The embodiments of the application, together with its details, are described in this specification.

[0035] Figure 1 is a schematic diagram of a diesel engine sequential supercharging control valve fault diagnosis process provided by one or more embodiments of the present application;

[0036] Figure 2 is a schematic diagram of a curve of two pressure fluctuations of a sequential supercharging control valve provided by one or more embodiments of the present application;

[0037] Figure 3 is a schematic diagram of a curve of one pressure fluctuation of a sequential supercharging control valve provided by one or more embodiments of the present application. DETAILED DESCRIPTION

[0038] The application will be further described with reference to the drawings and embodiments.

[0039] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0040] It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. It should also be noted that, as used in this specification and the appended claims, the singular form "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Furthermore, it is to be understood that the terms "comprising," "including," and "having" can be used interchangeably.

[0041] Sequential supercharging, principle: for a diesel engine with two or more than two superchargers, by controlling the opening and closing of the valve, the selective work of the supercharger is realized.

[0042] For example, at low load or low speed, the number of working superchargers is reduced, and the working efficiency of the remaining superchargers is improved; at high load or high speed, the number of working superchargers is increased to meet the power demand of the diesel engine.

[0043] The following embodiments give a diesel engine sequential supercharging control valve fault diagnosis method and system, by reading and analyzing the change of supercharger speed and hydraulic oil pressure, setting the sequential supercharging control valve sticking alarm limit value, diagnosing the fault of the sequential supercharging control valve sticking.

[0044] Embodiment one:

[0045] The method comprises the following steps:

[0046] Obtaining hydraulic oil pressure data for driving the action of the sequential supercharging control valve during the operation of the diesel engine;

[0047] If the number of times that the hydraulic oil pressure changes by more than the first threshold value within a set time period is 1, the corresponding sequential supercharging control valve is determined to be faulty;

[0048] Obtaining the rotational speed data of each supercharger, extracting the rotational speed of the controlled supercharger and the rotational speed of the commonly used supercharger, and obtaining the supercharger rotational speed deviation percentage by using: (rotational speed of controlled supercharger-rotational speed of commonly used supercharger) / rotational speed of commonly used supercharger;

[0049] When the supercharger rotational speed deviation percentage corresponding to the faulty sequential supercharging control valve is greater than the second threshold value, the corresponding intake valve of the sequential supercharging control valve is determined to be stuck, and when the supercharger rotational speed deviation percentage is less than the third threshold value, the corresponding exhaust valve of the sequential supercharging control valve is determined to be stuck.

[0050] The embodiment is applicable to a diesel engine with a sequential supercharging system and a hydraulic drive mode for sequential supercharging.

[0051] The sequential supercharging system comprises a plurality of superchargers, of which 1-2 are commonly used superchargers that are always in working state with the operation of the engine, and the rest are controlled superchargers that are sequentially involved in work with the increase of the engine speed and load.

[0052] Each controlled supercharger is provided with at least one intake valve and one exhaust valve for controlling the intake and exhaust of the supercharger.

[0053] During the sequential supercharging switching process, the hydraulic oil drives the action of the hydraulic cylinder, the exhaust valve is actuated first, the exhaust gas drives the supercharger to rotate when flowing through the supercharger, and after a certain interval of time, the intake valve is actuated again, at which time the compressed air enters the diesel engine.

[0054] The fault diagnosis process of the embodiment, as shown in Figure 1 includes the following steps:

[0055] Grabbing the diesel engine data in the running state. In this embodiment, the data collector is used to obtain the running data of the diesel engine to be diagnosed. The data collector is not limited in specific type, and any hardware device capable of reading the diesel engine running state data can be used. The diesel engine data obtained is output in the form of a curve with time as the horizontal coordinate.

[0056] Extracting the hydraulic oil pressure data in the diesel engine data, when the hydraulic oil pressure fluctuation value within 5 seconds is greater than 10 bar, it is determined that the sequential supercharging switching process, further determine the number of hydraulic oil pressure fluctuations within 5 seconds; when the hydraulic oil pressure fluctuation value within 5 seconds is not greater than 10 bar, return to the data extraction step.

[0057] In this embodiment, the first set time period and the second set time period are both 5 seconds, and the first threshold value is 10 bar.

[0058] When the number of hydraulic oil pressure fluctuations within 5 seconds is 2 times, it is determined that the sequential supercharging normal switching, (when the sequential supercharging intervention works, the exhaust valve acts first and the intake valve acts later, there are two control valve action processes, so the hydraulic oil pressure fluctuates 2 times is normal state), as shown in Figure 2 .

[0059] Figure 2 The horizontal coordinate in is time, and each grid in the horizontal coordinate is 5 seconds. It can be seen that the pressure of the hydraulic oil fluctuates twice within 5 seconds (has two troughs). The first fluctuation drops below 60 bar, and then recovers to 100 bar. The second fluctuation drops below 80 bar, and then recovers to 100 bar.

[0060] When the number of hydraulic oil pressure fluctuations within 5 seconds is 1 time, it is determined that the sequential supercharging control valve has a sticking phenomenon, as shown in Figure 3 , then the next step is determined.

[0061] Figure 3 The horizontal coordinate in is time, and each grid in the horizontal coordinate is 5 seconds. It can be seen that the pressure of the hydraulic oil fluctuates, and within 5 seconds, it drops below 60 bar, and then recovers to 100 bar, and only one fluctuation occurs. When the first fluctuation occurs, it is considered that only one group of the intake valve and the exhaust valve in the sequential supercharging control valve works normally, and the other group may have a sticking phenomenon, but it needs to be further determined whether the intake valve or the exhaust valve is stuck.

[0062] Obtaining the speed of each supercharger of the engine, extracting the controlled supercharger speed and the commonly used supercharger speed;

[0063] Setting A as the supercharger speed deviation percentage, that is, A = (controlled supercharger speed - commonly used supercharger speed) / commonly used supercharger speed;

[0064] When A > 10%, it is determined that the supercharger speed positive deviation is too large, the intake valve of the controlled supercharger is stuck, and the corresponding warning information or early warning information is reported;

[0065] When A < -10%, it is determined that the turbocharger speed negative deviation is too large, the exhaust valve of the controlled turbocharger is stuck, and corresponding reminder information or early warning information is reported.

[0066] In this embodiment, the second threshold is 10%, and the third threshold is -10%.

[0067] The above process extracts the hydraulic oil pressure reflecting the action of the sequential supercharging control valve and the speed of each turbocharger in the operation data of the diesel engine as judgment data, uses the characteristic that there are two control valve action processes when the sequential supercharging intervention works as a judgment basis, locates the sequential supercharging control valve that has stuck by analyzing the characteristics of the obtained data curve, distinguishes whether the intake valve or the exhaust valve of the sequential supercharging control valve has stuck, and issues a corresponding reminder. Thus, the engine operation fault can be located in time and accurately, and the next step of disposal can be facilitated for the maintenance personnel.

[0068] Embodiment two:

[0069] The system for implementing the sequential supercharging control valve fault diagnosis method of the diesel engine in embodiment one comprises:

[0070] The data acquisition unit is configured to obtain the hydraulic oil pressure data for driving the action of the sequential supercharging control valve and the speed data of each turbocharger during the operation of the diesel engine.

[0071] The data processing unit is configured to, within a set time period, if the number of times that the hydraulic oil pressure changes by more than the first threshold value is 1, the corresponding sequential supercharging control valve has a fault.

[0072] The controlled turbocharger speed and the common turbocharger speed are extracted, and the turbocharger speed deviation percentage is obtained by using (controlled turbocharger speed-common turbocharger speed) / common turbocharger speed.

[0073] When the turbocharger speed deviation percentage of the sequential supercharging control valve corresponding to the fault appears is greater than the second threshold value, the intake valve in the corresponding sequential supercharging control valve has a stuck fault, and when the turbocharger speed deviation percentage is less than the third threshold value, the exhaust valve in the corresponding sequential supercharging control valve has a stuck fault.

[0074] The diagnosis and early warning unit is configured to, when the intake valve or the exhaust valve in the sequential supercharging control valve has a stuck fault, report corresponding reminder information or early warning information.

[0075] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of diagnosing a fault of a control valve of a sequential turbocharging system for a diesel engine, characterized by, The method comprises the following steps: Obtaining hydraulic oil pressure data for driving the action of the sequential supercharging control valve during diesel engine operation; If the hydraulic oil pressure changes more than 1 time within a set time period, the corresponding sequential supercharging control valve is determined to have a fault; Obtaining the rotational speed data of each supercharger, extracting the controlled supercharger rotational speed and the commonly used supercharger rotational speed, and obtaining the supercharger rotational speed deviation percentage by using: (controlled supercharger rotational speed - commonly used supercharger rotational speed) / commonly used supercharger rotational speed; When the supercharger rotational speed deviation percentage of the sequential supercharging control valve corresponding to the fault is greater than a second threshold value, the intake valve of the corresponding sequential supercharging control valve is determined to have a jamming fault, and when the supercharger rotational speed deviation percentage is less than a third threshold value, the exhaust valve of the corresponding sequential supercharging control valve is determined to have a jamming fault.

2. The method of diagnosing a failure of a control valve of a sequential turbocharging system for a diesel engine according to claim 1, characterized by, The diesel engine is equipped with multiple sets of superchargers, which are divided into commonly used superchargers and controlled superchargers.

3. The method of diagnosing a failure of a control valve of a sequential turbocharging system for a diesel engine according to claim 2, characterized by, The commonly used superchargers are always in a working state during the operation of the diesel engine, and the remaining superchargers are controlled superchargers, which are switched into a working state according to the load change of the diesel engine.

4. The method of diagnosing a failure of a control valve of a sequential turbocharging system for a diesel engine according to claim 1, characterized by, The sequential supercharging control valve has a set of intake valves and exhaust valves, and each set of intake valves and exhaust valves corresponds to a supercharger and is used to control the intake and exhaust of the supercharger.

5. The method of diagnosing a failure of a control valve of a sequential turbocharging system for a diesel engine according to claim 1, characterized by, If the hydraulic oil pressure changes more than 1 time within a set time period, the corresponding sequential supercharging control valve is determined to have a fault, which comprises the following steps: If the hydraulic oil pressure changes more than 1 time within a set time period, the corresponding sequential supercharging control valve is determined to have a fault, which comprises the following steps: If the hydraulic oil pressure changes more than 1 time within a set time period, the corresponding sequential supercharging control valve is determined to have a fault, which comprises the following steps: If the hydraulic oil pressure changes more than 1 time within a set time period, the corresponding sequential supercharging control valve is determined to have a fault, which comprises the following steps:

6. The method of diagnosing a failure of a control valve of a sequential turbocharging system for a diesel engine according to claim 5, characterized by, If the hydraulic oil pressure changes more than 1 time within a set time period, the corresponding sequential supercharging control valve is determined to have a fault, which comprises the following steps: When the pressure fluctuation frequency is 2, the corresponding sequential supercharging control valve is determined to be in normal operation.

7. The method of diagnosing a failure of a control valve of a sequential turbocharging system for a diesel engine according to claim 6, characterized by, When the sequential supercharging control valve is in normal operation and is switched into a working state, the exhaust valve is actuated before the intake valve.

8. The method of diagnosing a failure of a control valve of a sequential turbocharging system for a diesel engine according to claim 1, characterized by, A is the supercharger rotational speed deviation percentage, that is, A = (controlled supercharger rotational speed - commonly used supercharger rotational speed) / commonly used supercharger rotational speed.

9. The method of diagnosing a failure of a control valve of a sequential turbocharging system for a diesel engine according to claim 8, characterized by, When A is greater than the second threshold value, it is determined that the positive deviation of the supercharger rotational speed is too large, the intake valve corresponding to the controlled supercharger is jammed, and corresponding warning information or early warning information is reported; When A is less than the third threshold value, it is determined that the negative deviation of the supercharger rotational speed is too large, the exhaust valve corresponding to the controlled supercharger is jammed, and corresponding warning information or early warning information is reported.

10. A fault diagnosis system for a control valve of a diesel engine sequential turbocharging, characterized by, The method comprises the following steps: The data acquisition unit is configured to obtain the hydraulic oil pressure data for driving the action of the sequential supercharging control valve during diesel engine operation and the rotational speed data of each supercharger; The data processing unit is configured to determine that the corresponding sequential supercharging control valve has a fault if the hydraulic oil pressure changes more than 1 time within a set time period; The controlled supercharger rotational speed and the commonly used supercharger rotational speed are extracted, and the supercharger rotational speed deviation percentage is obtained by using: (controlled supercharger rotational speed - commonly used supercharger rotational speed) / commonly used supercharger rotational speed; When the turbo speed deviation percentage corresponding to the malfunctioning sequential supercharging control valve is greater than the second threshold value, a stuck fault occurs in the intake valve of the corresponding sequential supercharging control valve, and is less than the third threshold value, a stuck fault occurs in the exhaust valve of the corresponding sequential supercharging control valve; The diagnosis and early warning unit is configured to report corresponding reminder information or early warning information when a stuck fault occurs in the intake valve or the exhaust valve of the sequential supercharging control valve.

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