A control method and control system for a diesel engine runaway

Abstract

The application provides a diesel engine runaway control method and control system, comprising a diesel engine speed acquisition and processing method, a diesel engine runaway fault diagnosis method, a diesel engine runaway fault processing method, the diesel engine speed acquisition and processing method is used for judging whether the diesel engine has an overspeed problem, the diesel engine runaway fault diagnosis method is used for judging a runaway fault, and the diesel engine runaway fault processing method is used for processing the runaway fault. The application has the beneficial effects that the cause of the diesel engine runaway can be judged, different control strategies are adopted to effectively control the diesel engine, and thus the safety of the diesel engine work is improved.

Description

Technical Field

[0001] This invention belongs to the field of diesel engine technology, and in particular relates to a control method and control system for a diesel engine flying car. Background Technology

[0002] Diesel engine runaway refers to a malfunction in which the engine speed becomes uncontrollable, increasing and exceeding the engine's maximum operating speed. Prolonged operation of a diesel engine in a runaway state often leads to serious malfunctions such as cylinder knock, connecting rod bending, crankshaft breakage, and cylinder block cracking, and can even directly threaten personal safety.

[0003] Diesel engine runaway is mostly caused by high-pressure pump jamming, but sometimes it can also be caused by sudden loss of load during operation or the transmission dragging the diesel engine when the vehicle is going downhill.

[0004] Therefore, determining whether a diesel engine runaway is caused by a stuck high-pressure pump or other reasons, and adopting different control strategies to improve the safety of diesel engine operation, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] In view of this, the present invention aims to propose a control method and control system for diesel engine runaway, which is used to determine the cause of diesel engine runaway and adopt different control strategies to effectively control the diesel engine and improve the safety of diesel engine operation.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0007] A method for controlling diesel engine overspeed includes a diesel engine speed acquisition and processing method, a diesel engine overspeed fault diagnosis method, and a diesel engine overspeed fault handling method. The diesel engine speed acquisition and processing method is used to determine whether the diesel engine has an overspeed problem, the diesel engine overspeed fault diagnosis method is used to determine the overspeed fault, and the diesel engine overspeed fault handling method is used to handle the overspeed fault.

[0008] Furthermore, the diesel engine speed acquisition and processing method includes the following steps:

[0009] A1. Dual-channel, dual-redundant acquisition of speed signals;

[0010] A2. Determine if the difference between the two speed signals is ≤50 r / min;

[0011] A3. Yes, then the first speed signal is used for diesel engine speed control and overspeed fault judgment.

[0012] A4. If not, the signal with the lower speed value is the fault signal, and a fault alarm is set. The signal with the higher value is used for diesel engine speed control and overspeed fault diagnosis.

[0013] Furthermore, the diesel engine overrun fault diagnosis method includes the following steps:

[0014] B1. During diesel engine operation, the fuel supply amount of the high-pressure pump rack is collected in real time;

[0015] B2. When the speed is higher than the maximum operating speed of the diesel engine, determine the fuel supply amount of the high-pressure pump;

[0016] B3. Determine whether the displacement of the oil supply rack returns to zero within 0.5 seconds;

[0017] B4. Yes, then the diesel engine runaway is caused by the sudden loss of load during diesel engine operation or the transmission dragging backward when the vehicle is going downhill.

[0018] B5. No, then the diesel engine runaway is caused by the high-pressure pump jamming.

[0019] Furthermore, the diesel engine overrun fault handling method includes the following steps:

[0020] C1. During the operation of the diesel engine, the diesel engine speed and the fuel supply amount of the high-pressure pump are collected in real time;

[0021] C2. When the speed is higher than the maximum operating speed of the diesel engine, determine the amount of fuel supplied by the high-pressure pump;

[0022] C3. Determine whether the displacement of the oil supply rack returns to zero within 0.5 seconds;

[0023] C4. If yes, the control system will reduce fuel and will not perform engine shutdown control.

[0024] C5. If not, the control system will forcibly cut off the oil supply and shut down the machine.

[0025] Furthermore, a control system for a diesel-powered aircraft includes:

[0026] The system includes a speed acquisition module, a high-pressure pump oil supply rack acquisition module, a control unit, an oil cut-off module, and a high-pressure pump oil supply rack drive module. All of these modules are connected to the control unit.

[0027] The speed acquisition module is used to acquire diesel engine speed information in real time;

[0028] The high-pressure pump fuel supply rack acquisition module is used to acquire the fuel supply rack value of the diesel engine high-pressure pump in real time.

[0029] The control unit processes and analyzes the speed signal and the high-pressure pump oil supply rack signal, controls the diesel engine and determines the cause of the overrun, and takes corresponding handling strategies based on the cause of the diesel engine overrun.

[0030] The fuel cut-off module receives a command from the control unit and performs a fuel cut-off operation to disconnect the diesel engine's fuel circuit;

[0031] The high-pressure pump oil supply rack drive module adjusts the oil supply of the high-pressure pump through the control unit. Upon receiving the oil reduction command, it controls the high-pressure pump rack to return to zero, thereby achieving the purpose of oil reduction.

[0032] Compared with existing technologies, the control method and control system for a diesel engine flying car described in this invention have the following advantages:

[0033] The present invention discloses a method and control system for controlling diesel engine runaway, which can determine the cause of diesel engine runaway and adopt different control strategies to effectively control the diesel engine, thereby improving the safety of diesel engine operation. Attached Figure Description

[0034] 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:

[0035] Figure 1 This is a schematic diagram of the diesel engine speed acquisition and processing method according to an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of the diesel engine overspeed fault diagnosis method according to an embodiment of the present invention;

[0037] Figure 3 This is a schematic flowchart of the diesel engine overspeed fault control method according to an embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram of the composition structure of the diesel engine control system according to an embodiment of the present invention. Detailed Implementation

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0040] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0041] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0042] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0043] like Figures 1 to 4 As shown, in the first aspect, this application provides a diesel engine speed acquisition and processing method. The technical solution of this invention is implemented as follows: the diesel engine speed value is acquired in real time during diesel engine operation to determine whether there is an overspeed problem. In order to improve the reliability of the system, a dual-path redundancy design for speed is adopted. Under normal circumstances, two speed signals are acquired simultaneously, with the first signal used as the control signal. At the same time, the system compares the two speed signals in real time. When the difference between the two speed signals is ≥50 r / min (which can be calibrated), for the safety of diesel engine operation, the speed signal with the higher value is selected, and the one with the lower speed value is determined to be a fault signal, and a fault alarm is set. The one signal with the higher value is used for diesel engine speed control and overspeed fault judgment.

[0044] Secondly, this application provides a diagnostic method for diesel engine runaway faults. During diesel engine operation, the position of the high-pressure pump fuel supply rack is collected in real time. After the diesel engine speed rapidly increases and exceeds the maximum operating speed (which can be calibrated), the position of the fuel supply rack is judged in real time. If the rack position does not return to zero within 0.5 seconds (which can be calibrated) after the speed exceeds the maximum operating speed, it is judged that the diesel engine runaway fault is caused by high-pressure pump jamming. Otherwise, it is judged that the diesel engine runaway is caused by other reasons.

[0045] Thirdly, this application provides a method for handling diesel engine runaway faults. A fuel cut-off solenoid valve is installed in the diesel engine fuel line. Under normal operation, it is in the engaged state, and the fuel line is unobstructed. When the system determines that a diesel engine runaway fault caused by high-pressure pump jamming occurs, the power supply to the fuel cut-off solenoid valve is disconnected, the diesel fuel line is cut off, and the diesel engine is automatically shut down to protect the diesel engine.

[0046] Fourthly, this application provides a diesel engine control system, comprising:

[0047] a) Speed ​​acquisition module, used to acquire diesel engine speed information in real time;

[0048] b) High-pressure pump fuel supply rack acquisition module, used to acquire the fuel supply rack value of the diesel engine high-pressure pump in real time (representing the amount of fuel supplied);

[0049] c) Control unit: processing and analysis of speed signal and high-pressure pump oil supply rack signal; diesel engine control and judgment of runaway fault causes; and taking corresponding handling strategies according to the cause of diesel engine runaway.

[0050] d) The fuel cut-off module, upon receiving a command from the control unit, performs a fuel cut-off operation to disconnect the diesel engine's fuel circuit;

[0051] e) The high-pressure pump oil supply rack drive module, through the control unit, realizes the adjustment of the high-pressure pump oil supply. After receiving the oil reduction command, it controls the high-pressure pump rack to return to zero, thereby achieving the purpose of oil reduction.

[0052] Example 1

[0053] like Figure 1 As shown, the diesel engine speed value is collected in real time during operation for speed control and to determine if there is an overspeed problem. To improve the reliability of the system, the speed signal acquisition adopts a dual-redundant design. Under normal circumstances, two speed signals are acquired simultaneously. The first speed signal is used as the control signal by default to realize the speed control and overspeed fault detection of the diesel engine. At the same time, the system compares the two speed signals in real time. When the difference between the two speed signals is ≥50r / min (which can be calibrated), the lower speed value is determined to be the fault signal, and a fault alarm is set. The higher speed value is used for speed control and overspeed fault detection.

[0054] like Figure 2 As shown, the position of the high-pressure pump fuel supply rack is collected in real time during diesel engine operation. After the diesel engine speed rapidly increases and exceeds the maximum operating speed (which can be calibrated), the fuel supply rack position is judged in real time. If the overspeed is caused by the sudden loss of load during diesel engine operation or the transmission dragging the diesel engine when the vehicle is going downhill, the fuel supply rack will quickly return to zero after the speed exceeds the maximum operating speed. If the fuel supply rack position does not return to zero within 0.5 seconds (which can be calibrated) after the diesel engine speed exceeds the maximum operating speed, it is judged that the diesel engine overspeed is caused by the high-pressure pump jamming.

[0055] like Figure 3 As shown, a fuel cut-off solenoid valve is installed in the diesel engine fuel line. The fuel cut-off solenoid valve is powered by 24V and is in the energized state during normal operation, ensuring unobstructed fuel flow. When the system determines that a diesel engine overrunning fault is caused by high-pressure pump jamming, the control unit issues a fuel cut-off command to disconnect the power supply to the fuel cut-off solenoid valve, cut off the diesel fuel line, and achieve automatic shutdown of the diesel engine to protect it. When the system determines that the overrunning is caused by a sudden loss of load during diesel engine operation or by the transmission dragging the diesel engine downhill, the system controls the fuel supply rack to return to zero without cutting off the fuel line. When the speed drops below the maximum operating speed of the diesel engine, the system resumes normal control.

[0056] Figure 4 This is a schematic diagram of the composition of a diesel engine control system provided in an embodiment of the present invention. The diesel engine control system includes: a speed acquisition module, a high-pressure pump fuel supply rack acquisition module, a control unit, a fuel cut-off module, and a high-pressure pump fuel supply rack drive module.

[0057] a) The speed acquisition module collects diesel engine speed information in real time for diesel engine speed control and diesel engine overspeed fault diagnosis. To improve system reliability, a dual-redundancy design is adopted.

[0058] b) High-pressure pump fuel supply rack acquisition module, which collects the diesel engine high-pressure pump fuel supply rack value in real time, for diesel engine fuel supply control and to determine whether there is a cause of runaway due to high-pressure pump fuel supply rack jamming;

[0059] c) The control unit processes and analyzes the speed signal and the high-pressure pump fuel supply rack signal. Through comprehensive analysis, it determines whether the diesel engine runaway fault is caused by high-pressure pump fuel supply rack jamming, or by a sudden drop in load during diesel engine operation, or by the transmission dragging the diesel engine downhill. The control unit adopts corresponding control strategies based on the specific cause of the diesel engine runaway. If it is caused by high-pressure pump fuel supply rack jamming, it controls the fuel cut-off module to perform a fuel cut-off operation and force the diesel engine to stop. If it is caused by a sudden drop in diesel engine load or transmission dragging, it controls the high-pressure pump fuel supply rack drive module to perform a fuel reduction operation. The control unit can calibrate the fuel cut-off operation response time based on diesel engine test verification (default is 0.5 seconds).

[0060] d) Fuel cut-off module: If the system determines that the diesel engine overrun is caused by the high-pressure pump fuel supply rack jamming, the control unit issues a fuel cut-off command, the fuel cut-off module activates, cuts off the diesel engine fuel circuit, and realizes the rapid shutdown of the diesel engine to protect the diesel engine;

[0061] e) High-pressure pump fuel supply rack drive module: Under normal circumstances, this module adjusts the fuel supply of the high-pressure pump through the control unit. If the diesel engine runs away due to a sudden drop in diesel engine load or gearbox drag, the control unit issues a fuel reduction command to control the high-pressure pump fuel supply rack to return to zero, thereby reducing the fuel supply. When the diesel engine speed is lower than the maximum operating speed of the diesel engine, the control system resumes normal control.

[0062] 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 control method for a diesel engine-powered vehicle, implemented by the control system of the diesel engine-powered vehicle, characterized in that: The invention includes a diesel engine speed acquisition and processing method, a diesel engine overspeed fault diagnosis method, and a diesel engine overspeed fault handling method. The diesel engine speed acquisition and processing method is used to determine whether the diesel engine has an overspeed problem, the diesel engine overspeed fault diagnosis method is used to determine the overspeed fault, and the diesel engine overspeed fault handling method is used to handle the overspeed fault. The diesel engine overrun fault diagnosis method includes the following steps: B1. During diesel engine operation, the fuel supply amount of the high-pressure pump rack is collected in real time; B2. When the speed is higher than the maximum operating speed of the diesel engine, determine the fuel supply amount of the high-pressure pump; B3. Determine whether the displacement of the oil supply rack returns to zero within 0.5 seconds; B4. Yes, then the diesel engine runaway is caused by the sudden loss of load during diesel engine operation or the transmission dragging backward when the vehicle is going downhill. B5. No, then the diesel engine runaway is caused by the high-pressure pump jamming. The diesel engine overrun fault handling method includes the following steps: C1. During the operation of the diesel engine, the diesel engine speed and the fuel supply amount of the high-pressure pump are collected in real time; C2. When the speed is higher than the maximum operating speed of the diesel engine, determine the amount of fuel supplied by the high-pressure pump; C3. Determine whether the displacement of the oil supply rack returns to zero within 0.5 seconds; C4. If yes, the control system will reduce fuel and will not perform engine shutdown control. C5. If not, the control system will forcibly cut off the oil supply and shut down the machine. The control system of the diesel-powered airplane includes: The system includes a speed acquisition module, a high-pressure pump oil supply rack acquisition module, a control unit, an oil cut-off module, and a high-pressure pump oil supply rack drive module. All of these modules are connected to the control unit. The speed acquisition module is used to acquire diesel engine speed information in real time; The high-pressure pump fuel supply rack acquisition module is used to acquire the fuel supply rack value of the diesel engine high-pressure pump in real time. The control unit processes and analyzes the speed signal and the high-pressure pump oil supply rack signal, controls the diesel engine and determines the cause of the overrun, and takes corresponding handling strategies based on the cause of the diesel engine overrun. The fuel cut-off module receives a command from the control unit and performs a fuel cut-off operation to disconnect the diesel engine's fuel circuit; The high-pressure pump oil supply rack drive module adjusts the oil supply of the high-pressure pump through the control unit. Upon receiving the oil reduction command, it controls the high-pressure pump rack to return to zero, thereby achieving the purpose of oil reduction.

2. The control method for a diesel engine overrunning engine according to claim 1, characterized in that: The diesel engine speed acquisition and processing method includes the following steps: A1. Dual-channel, dual-redundant acquisition of speed signals; A2. Determine if the difference between the two speed signals is ≤50 r / min; A3. Yes, then the first speed signal is used for diesel engine speed control and overspeed fault judgment. A4. If not, the signal with the lower speed value is the fault signal, and a fault alarm is set. The signal with the higher value is used for diesel engine speed control and overspeed fault diagnosis.

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