Gas rail assembly and control method for high-pressure direct injection gas engine

Abstract

The present application relates to a gas rail assembly and control method for a high-pressure direct-injection gas engine. Since a first oil return line is added between the diesel line and the gas line, and a corresponding debugging control component is used to determine whether to enter the debugging mode, the diesel entering the gas rail during the debugging process is recovered into the fuel tank of the diesel line, thereby adding a diesel debugging mode for market fault identification. At the same time, it solves the problem of the existing single diesel mode, in which a large amount of diesel will be retained in the gas line, i.e., the gas rail, over time. When the gas is introduced again, this part of the diesel will increase the smoke density of the engine exhaust, causing environmental pollution.

Description

Technical Field

[0001] The present application relates to the technical field of automobile engines, and in particular to a gas rail assembly and a control method for a high-pressure direct injection gas engine. Background Art

[0002] When testing a diesel-piloted natural gas direct injection engine using only diesel, the high pressure differential between the gas and oil rails (diesel pressure 320 bar, gas pressure 0 bar) causes diesel to enter the gas rail through the gap in the injector assembly and fill the rail to a pressure of 60 bar. Once filled, the diesel then flows through the gas rail, along the gas line, and into the pressure balancing valve, where it then opens the gas shutoff valve and flows out of the gas inlet pipe.

[0003] During dual fuel injection, i.e. normal operation, the pressure difference is small, and only a small amount of diesel enters the gas side, and is injected into the cylinder to perform work during the injection process. However, there are the following problems:

[0004] When in diesel-only mode (during debugging), a large amount of diesel will remain in the gas pipeline, i.e. the gas rail, over time. When the gas is introduced again, this part of diesel will increase the smoke density of the engine exhaust, causing environmental pollution.

[0005] However, if a check valve is added to the gas pipeline, the flow resistance of the pipeline will be increased, which is not conducive to high-pressure injection. In addition, the leaked oil will only enter the gas rail side in a small stream and will not generate high pressure, so the one-way valve will not serve the purpose of flow blocking. Summary of the Invention

[0006] The present invention provides a gas rail assembly and control method for a high-pressure direct-injection gas engine. This method addresses the problem in the related art where, in diesel-only mode (during commissioning), a large amount of diesel fuel accumulates in the gas pipeline, i.e., the gas rail, over time. When gas is reintroduced, this diesel fuel increases engine exhaust smoke, causing environmental pollution.

[0007] In a first aspect, a gas rail assembly for a high-pressure direct injection gas engine is provided, comprising:

[0008] A diesel pipeline comprising a fuel tank, a fuel pump and a fuel rail connected in series, wherein the fuel rail is connected to a dual fuel injector;

[0009] The gas pipeline includes a gas cylinder, a buffer tank, a shutoff valve, a pressure balancing valve and a gas rail connected in series; the gas rail is connected to the dual-fuel injector; the oil rail is connected to the pressure balancing valve;

[0010] a first oil return pipeline, two ends of which are connected to the gas rail and the oil tank respectively;

[0011] The debugging control component is connected to the shutoff valve, the gas rail and the first oil return pipeline; the debugging control component is used to control the opening and closing of the first oil return pipeline according to the pressure in the gas rail and the opening and closing of the shutoff valve to recover the diesel in the gas rail.

[0012] Since a first oil return line is added between the diesel line and the gas line, and a corresponding debugging control component is provided, the debugging control component is used to determine whether to enter the debugging mode, so that the diesel entering the gas rail during the debugging process is recovered into the fuel tank 9 of the diesel line, thereby adding a diesel debugging mode for market fault identification. At the same time, it solves the problem that in the existing single diesel mode, that is, during debugging, a large amount of diesel will be retained in the gas line, that is, the gas rail, as time accumulates. When the gas is introduced again, this part of the diesel will increase the smoke density of the engine exhaust, causing environmental pollution.

[0013] At the same time, it also solves the problem that adding a check valve in the gas pipeline will increase the flow resistance of the pipeline, which is not conducive to high-pressure injection; in addition, the leaked oil will only enter the gas rail side in a small stream and will not generate high pressure, so the one-way valve cannot serve the purpose of flow blocking.

[0014] In some embodiments, the debugging control component includes a vehicle ECU and a pressure sensor; the pressure sensor is disposed in the gas rail; the vehicle ECU is configured to determine whether to enter the debugging mode based on detection data from the pressure sensor.

[0015] In some embodiments, the first oil return pipeline includes an oil return solenoid valve and a first pipeline; the oil return solenoid valve is connected to the gas rail, and the oil return solenoid valve is connected to the oil tank through the first pipeline.

[0016] In some embodiments, a second oil return line and a third oil return line are further included, wherein both ends of the second oil return line are connected to the dual fuel injector and the fuel tank respectively; and both ends of the third oil return line are connected to the fuel rail and the fuel tank respectively.

[0017] In some embodiments, an oil collecting groove is provided on the bottom wall of the internal channel of the gas rail, and the length of the oil collecting groove is smaller than the length of the gas rail.

[0018] In some embodiments, the cross-section of the oil collecting tank is rectangular or semicircular, which can effectively collect the blowby oil for easy recovery.

[0019] In some embodiments, a filter is connected between the fuel tank and the fuel pump.

[0020] In a second aspect, a method for controlling a gas rail assembly for a high-pressure direct injection gas engine is provided, comprising the following steps:

[0021] Use the debugging control component to detect the pressure in the gas rail and the on / off state of the shut-off valve, and determine whether to enter the debugging mode;

[0022] If the pressure in the gas rail is detected to be zero and the shut-off valve is closed, the debugging mode is turned on and the first oil return line is connected to the oil tank;

[0023] If the pressure in the gas rail is not zero and the shut-off valve is closed, it indicates that the system has entered the debugging mode. Keep the first oil return line connected to the fuel tank.

[0024] If the pressure in the gas rail is not zero and the shut-off valve is connected, it is in normal mode and the connection between the first oil return line and the oil tank is cut off.

[0025] On the basis of normal operation, a special debugging mode is provided, and a method for detecting abnormalities in the debugging mode is also provided; at the same time, a good solution is provided to the existing single diesel mode, that is, during debugging, a large amount of diesel will be retained in the gas pipeline, that is, the gas rail, as time accumulates. When the gas is introduced again, this part of diesel will increase the engine's exhaust smoke and cause environmental pollution.

[0026] In some embodiments, the debugging control component is used to detect the pressure in the gas rail and the on / off state of the shutoff valve, and to determine whether to enter the debugging mode, further comprising the following steps:

[0027] If the pressure in the gas rail is detected to be zero and the shut-off valve is connected, it is an abnormal mode, and the shut-off valve is closed within the set time to cut off the connection between the first oil return line and the oil tank.

[0028] In some embodiments, after the debugging mode is run for a set time threshold, the connection between the first oil return line and the oil tank needs to be cut off.

[0029] The beneficial effects of the technical solution provided by this application include:

[0030] The embodiment of the present application provides a gas rail assembly and control method for a high-pressure direct-injection gas engine. Since a first return oil pipeline is added between the diesel pipeline and the gas pipeline, and a corresponding debugging control component is used to determine whether to enter the debugging mode, so that the diesel entering the gas rail during the debugging process is recovered into the fuel tank of the diesel pipeline, thereby adding a diesel debugging mode for market fault identification. At the same time, it solves the problem of the existing single diesel mode, in which a large amount of diesel will be retained in the gas pipeline, i.e., the gas rail, over time. When the gas is introduced again, this part of diesel will increase the smoke density of the engine exhaust, causing environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0032] Figure 1 A schematic diagram of a gas rail assembly for a high-pressure direct injection gas engine provided in an embodiment of the present application;

[0033] Figure 2 A schematic diagram of the structure of the gas rail provided in an embodiment of the present application.

[0034] In the figure: 1. Dual fuel injectors; 2. Fuel rail; 3. Gas cylinder; 4. Buffer tank; 5. Shut-off valve; 6. Pressure balance valve; 7. Gas rail; 8. Oil return solenoid valve; 9. Fuel tank; 10. Fuel pump; 11. Oil sump; 12. Filter. DETAILED DESCRIPTION

[0035] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0036] Dual-fuel natural gas engines are essentially just another version of traditional diesel engines, maintaining the same compression ratio. Compared to dual-fuel engines, dual-fuel engines offer greater flexibility and require no major engine modifications. Their operating principle is to inject a small amount of pilot diesel into the cylinder, which, upon compression and ignition, ignites the natural gas and air mixture injected into the cylinder.

[0037] This engine can operate in either a natural gas / diesel dual-fuel mode or purely diesel mode, combining the advantages of natural gas with the high fuel efficiency of diesel. Dual-fuel engines offer excellent economical efficiency, as the two fuels can be burned in an optimal ratio. This ensures engine power and speed while minimizing design conflicts between gaseous and liquid fuels. Furthermore, they offer low exhaust emissions and particulate matter emissions. Depending on the amount of pilot fuel, dual-fuel engines can be categorized as conventional natural gas / diesel engines and micro-pilot natural gas engines.

[0038] The present application provides a gas rail assembly and control method for a high-pressure direct-injection gas engine to address the problem in the related art that, when operating in diesel-only mode, a large amount of diesel fuel accumulates in the gas pipeline, i.e., the gas rail, over time. When the gas is reintroduced, this diesel fuel increases the smoke density of the engine's exhaust, causing environmental pollution.

[0039] See also Figure 1-Figure 2 , a gas rail assembly for a high-pressure direct injection gas engine, comprising:

[0040] The diesel pipeline includes a fuel tank 9, a fuel pump 10 and a fuel rail 2 connected in series. The fuel rail 2 is connected to a dual fuel injector 1; a filter 12 is connected between the fuel tank 9 and the fuel pump 10.

[0041] The gas pipeline includes a gas cylinder 3, a buffer tank 4, a shutoff valve 5, a pressure balance valve 6 and a gas rail 7 connected in series; the gas rail 7 is connected to the dual-fuel injector 1; the oil rail 2 is connected to the pressure balance valve 6;

[0042] A first oil return pipeline, the two ends of which are connected to the gas rail 7 and the oil tank 9 respectively;

[0043] The debugging control component is connected to the shut-off valve 5, the gas rail 7 and the first oil return pipeline; the debugging control component is used to control the on-off of the first oil return pipeline according to the pressure in the gas rail 7 and the on-off of the shut-off valve 5 to recover the diesel in the gas rail 7.

[0044] Since a first oil return line is added between the diesel line and the gas line, and a corresponding debugging control component is provided, the debugging control component is used to determine whether to enter the debugging mode, so that the diesel entering the gas rail during the debugging process is recovered into the fuel tank 9 of the diesel line, thereby adding a diesel debugging mode for market fault identification. At the same time, it solves the problem that in the existing single diesel mode, that is, during debugging, a large amount of diesel will be retained in the gas line, that is, the gas rail, as time accumulates. When the gas is introduced again, this part of the diesel will increase the smoke density of the engine exhaust, causing environmental pollution.

[0045] At the same time, it also solves the problem that adding a check valve in the gas pipeline will increase the flow resistance of the pipeline, which is not conducive to high-pressure injection; in addition, the leaked oil will only enter the gas rail side in a small stream and will not generate high pressure, so the one-way valve cannot serve the purpose of flow blocking.

[0046] It should be understood that Figure 1 The dual fuel injector 1 in the figure does not show the flow path of the fuel into the engine, but only shows four routes: natural gas circuit, diesel circuit, oil return circuit and electric circuit. Figure 1 There are different line types to distinguish them.

[0047] The pressure balancing valve 6 is a valve with special functions. In some industries, due to the large pressure difference or flow difference between the media (various flowable substances) in various parts of the pipeline or container, in order to reduce or balance the difference, a valve is installed between the corresponding pipelines or containers to adjust the relative balance of pressure on both sides, or to achieve flow balance by diversion. This valve is called a pressure balancing valve 6.

[0048] In some preferred embodiments, to facilitate the determination of whether to enter debug mode, the debug control component has the following settings:

[0049] The debugging control component includes a vehicle ECU and a pressure sensor. The pressure sensor is located in the gas rail 7. The vehicle ECU is used to determine whether to enter the debugging mode based on the detection data of the pressure sensor. The pressure sensor detects the pressure of the gas rail 7.

[0050] An ECU (Electronic Control Unit), also known as a driving computer or onboard computer, is a specialized automotive microcomputer controller, also known as a single-chip microcomputer. Like a standard single-chip microcomputer, it consists of a microprocessor (CPU), memory (ROM, RAM), input / output (I / O) interfaces, an analog-to-digital converter (A / D), and large-scale integrated circuits for shaping and driving functions.

[0051] The operating voltage range of a vehicle ECU is generally 6.5-16V (with voltage regulators at key locations), the operating current is 0.015-0.1A, and the operating temperature range is -40-80°C. It can withstand vibrations below 1000Hz, making ECU damage very unlikely. The CPU is the core component of the ECU, performing computation and control functions. When the engine is running, it collects signals from various sensors, performs calculations, and converts the results into control signals to control the operation of the controlled object. It also controls the memory (ROM, RAM), input / output (I / O) interfaces, and other external circuits. The program stored in the ROM is based on data obtained through precise calculations and extensive experiments. This inherent program continuously compares and calculates the signals collected from various sensors while the engine is running. The results of these comparisons and calculations control various engine parameters, such as ignition, air-fuel ratio, idle speed, and exhaust gas recirculation. The ECU also has self-diagnosis and protection functions. When a system fault occurs, it automatically records the fault code in RAM and, in response to protection measures, retrieves an alternative program from the inherent program to maintain engine operation.

[0052] Therefore, the vehicle ECU can store a certain setting program, that is, to determine whether to run the debugging mode.

[0053] Furthermore, the structure of the matching first oil return pipeline is: the first oil return pipeline includes an oil return solenoid valve 8 and a first pipeline; the oil return solenoid valve 8 is connected to the gas rail 7, and the oil return solenoid valve 8 is connected to the oil tank 9 through the first pipeline.

[0054] Similarly, the gas rail assembly for the high-pressure direct-injection gas engine also includes a second oil return line and a third oil return line. The two ends of the second oil return line are connected to the dual-fuel injector 1 and the fuel tank 9 respectively; the two ends of the third oil return line are connected to the oil rail 2 and the fuel tank 9 respectively. The function of the second oil return line and the third oil return line is to recover excess unused residual diesel in the oil rail 2 and the dual-fuel injector 1.

[0055] In some preferred embodiments, in order to facilitate the recovery of diesel in the gas rail 7, the following settings are provided:

[0056] An oil collecting groove 11 is provided on the bottom wall of the internal passage of the gas rail 7. The length of the oil collecting groove 11 is shorter than that of the gas rail 7 and the cross-section of the oil collecting groove 11 is rectangular or semicircular. This effectively collects the blowby oil for easy recovery.

[0057] The present application also proposes a control method for a gas rail assembly for a high-pressure direct injection gas engine, which comprises the following steps:

[0058] Step S01: Use the debugging control component to detect the pressure in the gas rail 7 and the on / off state of the shut-off valve 5, and determine whether to enter the debugging mode;

[0059] Step S02: If the pressure in the gas rail 7 is detected to be zero and the shut-off valve 5 is closed, the debugging mode is turned on and the first oil return line is connected to the oil tank 9;

[0060] Step S03: If the pressure in the gas rail 7 is not zero and the shutoff valve 5 is closed, it indicates that the debugging mode has been entered, and the first oil return line and the fuel tank 9 are kept connected. In the debugging mode, due to the gap between the mating parts of the dual-fuel injector 1, diesel backflows into the gas rail 7, and the gas rail 7 changes from zero pressure to pressure. At this time, the first oil return line and the fuel tank 9 are connected to recover the diesel.

[0061] Step S04: If the pressure in the gas rail 7 is detected to be non-zero and the shut-off valve 5 is connected, it is a normal mode, and the connection between the first oil return line and the oil tank 9 is cut off.

[0062] In normal mode, the fuel tank 9 , the fuel pump 10 and the fuel rail 2 provide diesel to the dual-fuel injector 1 ; the gas cylinder 3 , the buffer tank 4 , the shutoff valve 5 , the pressure balancing valve 6 and the gas rail 7 provide gas to the dual-fuel injector 1 .

[0063] The debugging control component is used to detect the pressure in the gas rail 7 and the on / off state of the shut-off valve 5, and to determine whether to enter the debugging mode, and further includes the following steps:

[0064] Step S05: If the pressure in the gas rail 7 is zero and the shutoff valve 5 is connected, it is an abnormal mode, and the shutoff valve 5 is closed within a set time, cutting off the connection between the first oil return line and the oil tank 9. This step indicates that there is a leak in the gas rail 7.

[0065] The above steps achieve, on the basis of normal operation, the provision of a special debugging mode, and also have a method for detecting abnormalities in the debugging mode; at the same time, it well solves the problem that in the existing single diesel mode, that is, during debugging, a large amount of diesel will be retained in the gas pipeline, that is, the gas rail, over time. When the gas is introduced again, this part of diesel will increase the smoke emission of the engine, causing environmental pollution.

[0066] In some preferred embodiments, after the debugging mode is run for a set time threshold, the connection between the first oil return line and the fuel tank 9 is disconnected. This step terminates the debugging mode and allows normal operation. At this time, the first oil return line is closed, while the second and third oil return lines continue to operate normally, thereby ensuring that normal functions are not affected.

[0067] The threshold value and the time period can be set as needed.

[0068] Principles of this application:

[0069] Since a first oil return line is added between the diesel line and the gas line, and a corresponding debugging control component is provided, the debugging control component is used to determine whether to enter the debugging mode, so that the diesel entering the gas rail during the debugging process is recovered into the fuel tank 9 of the diesel line, thereby adding a diesel debugging mode for market fault identification. At the same time, it solves the problem that in the existing single diesel mode, that is, during debugging, a large amount of diesel will be retained in the gas line, that is, the gas rail, as time accumulates. When the gas is introduced again, this part of the diesel will increase the smoke density of the engine exhaust, causing environmental pollution.

[0070] At the same time, it also solves the problem that adding a check valve in the gas pipeline will increase the flow resistance of the pipeline, which is not conducive to high-pressure injection; in addition, the leaked oil will only enter the gas rail side in a small stream and will not generate high pressure, so the one-way valve cannot serve the purpose of flow blocking.

[0071] It should be understood that Figure 1The dual fuel injector 1 in the figure does not show the flow path of the fuel into the engine, but only shows four routes: natural gas circuit, diesel circuit, oil return circuit and electric circuit. Figure 1 There are different line types to distinguish them.

[0072] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0073] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0074] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0075] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0076] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps of the functions specified in the block or blocks. In a typical configuration, the computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory. The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0077] Computer-readable media include permanent and non-permanent, removable and non-removable media that can store information using any method or technology. The information can be computer-readable instructions, data structures, program modules or other data.

[0078] Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory media such as modulated data signals and carrier waves. It should also be noted that the terms "comprises," "comprising," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not expressly listed or inherent to such process, method, article, or apparatus. In the absence of more constraints, an element defined by the phrase "comprises a . . . ..." does not preclude the existence of additional identical elements in the process, method, product, or apparatus that comprises the element.

[0079] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0080] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A gas rail assembly for a high-pressure direct injection gas engine, characterized in that: It includes: A diesel pipeline comprising a fuel tank (9), a fuel pump (10) and a fuel rail (2) connected in series, wherein the fuel rail (2) is connected to a dual fuel injector (1); A gas pipeline comprises a gas cylinder (3), a buffer tank (4), a shutoff valve (5), a pressure balancing valve (6) and a gas rail (7) connected in series in sequence; the gas rail (7) is connected to the dual-fuel injector (1); the oil rail (2) is in communication with the pressure balancing valve (6); a first oil return pipeline, the two ends of which are respectively connected to the gas rail (7) and the oil tank (9); A debugging control component is connected to the shutoff valve (5), the gas rail (7) and the first oil return pipeline; the debugging control component is used to control the opening and closing of the first oil return pipeline according to the pressure in the gas rail (7) and the opening and closing of the shutoff valve (5) to recover diesel in the gas rail (7).

2. The gas rail assembly for a high-pressure direct injection gas engine according to claim 1, characterized in that: The debugging control component comprises a vehicle ECU and a pressure sensor; the pressure sensor is arranged in the gas rail (7); the vehicle ECU is used to determine whether to enter a debugging mode based on detection data of the pressure sensor.

3. The gas rail assembly for a high-pressure direct injection gas engine according to claim 1, characterized in that: The first oil return pipeline comprises an oil return solenoid valve (8) and a first pipeline; the oil return solenoid valve (8) is connected to the gas rail (7), and the oil return solenoid valve (8) is connected to the oil tank (9) through the first pipeline.

4. The gas rail assembly for a high-pressure direct injection gas engine according to claim 1, characterized in that: It also includes a second oil return pipeline and a third oil return pipeline, wherein the two ends of the second oil return pipeline are respectively connected to the dual fuel injector (1) and the oil tank (9); and the two ends of the third oil return pipeline are respectively connected to the oil rail (2) and the oil tank (9).

5. The gas rail assembly for a high-pressure direct injection gas engine according to claim 1, characterized in that: An oil collecting groove (11) is provided on the bottom wall of the internal channel of the gas rail (7), and the length of the oil collecting groove (11) is smaller than the length of the gas rail (7).

6. The gas rail assembly for a high-pressure direct injection gas engine according to claim 5, characterized in that: The cross-sectional shape of the oil collecting tank (11) is rectangular or semicircular.

7. The gas rail assembly for a high-pressure direct injection gas engine according to claim 1, characterized in that: A filter (12) is connected between the fuel tank (9) and the fuel pump (10).

8. A method for controlling a gas rail assembly for a high-pressure direct injection gas engine according to claim 1, characterized in that: It includes the following steps: Using the debugging control component to detect the pressure in the gas rail (7) and the on / off state of the shutoff valve (5), and to determine whether to enter the debugging mode; If the pressure in the gas rail (7) is detected to be zero and the shutoff valve (5) is closed, the debugging mode is turned on and the first oil return line is connected to the oil tank (9); If the pressure in the gas rail (7) is not zero and the shutoff valve (5) is closed, it indicates that the debugging mode has been entered, and the first oil return line and the oil tank (9) are kept in communication; If the pressure in the gas rail (7) is detected to be non-zero and the shut-off valve (5) is connected, it is in normal mode and the connection between the first oil return line and the oil tank (9) is cut off.

9. The method for controlling a gas rail assembly for a high-pressure direct injection gas engine according to claim 8, wherein: The debugging control component is used to detect the pressure in the gas rail (7) and the on / off state of the shutoff valve (5), and to determine whether to enter the debugging mode, further comprising the following steps: If the pressure in the gas rail (7) is detected to be zero and the shutoff valve (5) is connected, it is an abnormal mode, and the shutoff valve (5) is closed within a set time, cutting off the connection between the first oil return line and the oil tank (9).

10. The method for controlling a gas rail assembly for a high-pressure direct injection gas engine according to claim 8, wherein: After the debugging mode is run to a set time threshold, the connection between the first oil return pipeline and the oil tank (9) is cut off.

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