A gas injection system, start-up strategy, and vehicle

Abstract

The application relates to a gas injection system, a starting strategy and a vehicle, which comprises a diesel injection system, a gas injection system, an oil injector provided with an injection valve, the injection valve being provided with a gas channel and an oil channel, the oil injector being connected with the diesel injection system through a diesel pipeline, connected with the gas injection system through a gas pipeline, and the diesel pipeline being connected with the gas channel and the oil channel, and the gas pipeline being connected with the gas channel, and an ECU for controlling the diesel injection system to be connected with the gas channel and the oil channel and cutting off the gas pipeline when the engine is in a low-temperature starting condition, and controlling the diesel injection system to be connected with the oil channel and controlling the gas injection system to be connected with the gas channel when the engine is in a normal-temperature starting condition. When starting at low temperature, the diesel pipeline is connected with the gas channel and the oil channel through the control of the ECU, and the oil channel and the gas channel are used to inject diesel oil, so that the injection amount of diesel oil is increased, and the difficulty of starting at low temperature is reduced.

Description

Technical Field

[0001] This invention relates to the field of automotive engine technology, specifically to a gas injection system, a starting strategy, and a vehicle. Background Technology

[0002] Currently, direct injection of natural gas with diesel ignition technology can effectively improve the overall thermal efficiency of the engine. The pressure of natural gas injected through the intake manifold or intake port is only 0.75 MPa, while the pressure of natural gas injected through direct injection reaches 30 MPa. Natural gas is difficult to ignite by compression, so spark ignition or diesel ignition is generally used.

[0003] In related technologies, the entire fuel supply and injection system of a direct-injection diesel ignition gas engine includes a balancing valve to maintain pressure balance between the two fuels. In this system, both fuels are injected through the same injector. Since diesel only serves as an ignition element, the required amount per cycle is very small, accounting for only 5% of the total injection volume. The number of fuel passages in the injection valve is small, and the nozzle diameter is small.

[0004] Because the injection valve has few and small oil passages, it cannot increase the amount of diesel fuel injected, resulting in difficulty starting at low temperatures. Furthermore, due to the flow restriction at the nozzle, simply increasing the diesel fuel pressure alone cannot solve the problem. Summary of the Invention

[0005] This application provides a gas injection system, a starting strategy, and a vehicle. By connecting the diesel fuel line to both the air and fuel lines simultaneously, during cold starts, the ECU controls the connection of the diesel fuel line to both the air and fuel lines. Both the fuel and air lines are used for diesel injection, thereby increasing the diesel injection volume and reducing the difficulty of cold starts. This solves the problem in related technologies where the injection valve has few and small fuel lines, which cannot increase the diesel injection volume and leads to difficulties in cold starts.

[0006] In a first aspect, embodiments of this application provide a gas injection system, comprising: a diesel injection system; a gas injection system; an injector equipped with an injection valve, the injection valve having an air passage and a fuel passage, the injector being connected to the diesel injection system via a diesel pipeline and to the gas injection system via a gas pipeline, the diesel pipeline being connected to the air passage and the fuel passage, and the gas pipeline being connected to the air passage; and an ECU, configured to control the diesel injection system to connect to the air passage and the fuel passage, and to disconnect the gas pipeline, when the engine is in a cold start condition; and to control the diesel injection system to connect to the fuel passage and the gas injection system to connect to the air passage when the engine is in a normal start condition. Because the diesel pipeline can be connected to both the air passage and the fuel passage simultaneously, during cold starts, the ECU controls the connection of the diesel pipeline to both the air passage and the fuel passage, ensuring that both the fuel passage and the air passage are used for diesel injection, thereby increasing the diesel injection volume and reducing the difficulty of cold starts.

[0007] In conjunction with the first aspect, in one embodiment, the diesel fuel line includes a first diesel fuel line and a second diesel fuel line. The first diesel fuel line is connected to the air intake system, and the second diesel fuel line is connected to the fuel line. When the engine is in a cold start condition, the first diesel fuel line and the air intake system are connected. When the engine is in a normal start condition, the first diesel fuel line and the air intake system are disconnected. By branching off a line from the downstream of the original diesel injection system's fuel rail and connecting it to the air intake system, when the engine is in a cold start condition, the ECU controls the first diesel fuel line to connect to the air intake system, the second diesel fuel line to connect to the fuel line, and disconnects the fuel gas line. Both the fuel line and the air intake system are used to inject diesel fuel. When the engine is in a normal start condition, the ECU controls the second diesel fuel line to connect to the fuel line, controls the fuel gas line to connect to the air intake system, and disconnects the first diesel fuel line. The air intake system is used to inject fuel gas, and the fuel line is used to inject diesel fuel.

[0008] In conjunction with the first aspect, in one embodiment, the gas injection system includes a two-position three-way valve. The two-position three-way valve has a first port, a second port, and a third port. The first port is connected to the first diesel fuel line, the second port is connected to the gas fuel line, and the third port is connected to the fuel injector. By branching off a line from the downstream of the original diesel fuel injection system's fuel rail and connecting it to one port of the two-position three-way valve, and connecting the gas fuel line from the original gas fuel injection system's fuel rail to the fuel injector to the other port of the two-position three-way valve, the two-position three-way valve is activated by the ECU according to commands issued by the engine operating conditions, completing the opening and closing of the two fuels, resulting in precise control and high efficiency.

[0009] In conjunction with the first aspect, in one embodiment, a check valve is installed at the end of the first diesel fuel line near the two-position three-way valve. The two-position three-way valve can isolate the two fuels, thereby preventing diesel fuel from entering the fuel gas line. Simultaneously, the check valve on the first diesel fuel line, located between the two-position three-way valve and the fuel rail, is a mechanical structure that prevents gas from entering the fuel line if the two-position three-way valve fails to seal, further improving the sealing performance of the injection system and enhancing safety.

[0010] In conjunction with the first aspect, in one embodiment, the diesel injection system includes a fuel tank, a filter, a fuel pump, and a fuel rail connected in sequence; the gas injection system includes a gas cylinder, a buffer tank, a shut-off valve, a balance valve, and a gas rail connected in sequence; the ECU is electrically connected to the shut-off valve, the gas rail, and the two-position three-way valve, and the injector is electrically connected to the fuel rail and the fuel tank. When the engine is in a cold start condition, diesel injection passes through the fuel tank, filter, fuel pump, fuel rail, and two-position three-way valve / injector in sequence; when the engine is in a normal start condition, diesel injection passes through the fuel tank, filter, fuel pump, fuel rail, and injector in sequence, while gas injection passes through the gas cylinder, buffer tank, shut-off valve, balance valve, gas rail, two-position three-way valve, and injector in sequence, making control convenient.

[0011] Secondly, embodiments of this application provide a starting strategy for a gas injection system, comprising the following steps: determining the engine's starting condition; when the engine is in a low-temperature starting condition, using the ECU to control the connection of the diesel injection system with the air circuit and the fuel circuit, and cutting off the gas pipeline; when the engine is in a normal-temperature starting condition, using the ECU to control the connection of the diesel injection system with the fuel circuit, and the connection of the gas injection system with the air circuit. Since the diesel pipeline can be connected to both the air circuit and the fuel circuit simultaneously, during low-temperature starting, by controlling the connection of the diesel pipeline with both the air circuit and the fuel circuit through the ECU, both the fuel circuit and the air circuit are used to inject diesel fuel, thereby increasing the amount of diesel fuel injected and reducing the difficulty of low-temperature starting.

[0012] In conjunction with the second aspect, in one embodiment, the diesel fuel pipeline includes a first diesel fuel pipeline and a second diesel fuel pipeline. The first diesel fuel pipeline is connected to the air intake system, and the second diesel fuel pipeline is connected to the fuel system. When the engine is in a cold start condition, the ECU controls the connection between the first diesel fuel pipeline and the air intake system. When the engine is in a normal start condition, the ECU controls the disconnection between the first diesel fuel pipeline and the air intake system. By branching off a line from the downstream of the original diesel injection system's fuel rail and connecting it to the air intake system, when the engine is in a cold start condition, the ECU controls the connection between the first diesel fuel pipeline and the air intake system, and the connection between the second diesel fuel pipeline and the fuel system, while disconnecting the fuel intake system. Both the fuel system and the air intake system are used to inject diesel fuel, increasing the amount of diesel fuel injected and reducing the difficulty of cold start. The two pipelines are controlled independently, making them convenient to use.

[0013] In conjunction with the second aspect, in one embodiment, the gas injection system includes a two-position three-way valve. The two-position three-way valve has a first interface, a second interface, and a third interface. The first interface is connected to the first diesel fuel line, the second interface is connected to the gas fuel line, and the third interface is connected to the fuel injector. The step of using the ECU to control the connection of the diesel injection system to the air circuit and the fuel circuit, and to disconnect the gas fuel line, includes: when the engine is in a low-temperature starting condition, using the ECU to control the first diesel fuel line to connect to the air circuit, the second diesel fuel line to connect to the fuel circuit, and disconnect the gas fuel line; when the engine is in a normal-temperature starting condition, using the ECU to control the second diesel fuel line to connect to the fuel circuit, control the gas fuel line to connect to the air circuit, and disconnect the first diesel fuel line.

[0014] In conjunction with the second aspect, in one embodiment, the step of using the ECU to control the connection of the diesel injection system with the air circuit and the fuel circuit, and to cut off the gas pipeline includes: when the ambient temperature is <℃, the engine coolant temperature is <℃, and the engine speed is <rpm, it is determined that the engine is in a low-temperature start-up condition, and the ECU controls a two-position three-way valve to connect the first diesel pipeline with the air circuit and to cut off the gas pipeline.

[0015] In conjunction with the second aspect, in one embodiment, the step of using the ECU to control the connection of the diesel injection system and the fuel line, and the connection of the gas injection system and the gas line includes: when the engine speed is greater than rpm, determining that the engine has started successfully, using the ECU to control a two-position three-way valve to connect the gas injection system and the gas line, and disconnecting the first diesel line and the gas line.

[0016] Thirdly, this application provides a vehicle including the aforementioned gas injection system. The gas injection system includes: a diesel injection system; a gas injection system; a fuel injector equipped with an injection valve, the injection valve having an air passage and a fuel passage; the fuel injector connected to the diesel injection system via a diesel pipeline and to the gas injection system via a gas pipeline, the diesel pipeline connecting to the air passage and the fuel passage, and the gas pipeline connecting to the air passage; and an ECU, configured to, when the engine is in a low-temperature starting condition, control the diesel injection system to connect to the air passage and the fuel passage, and to disconnect the gas pipeline; and when the engine is in a normal-temperature starting condition, control the diesel injection system to connect to the fuel passage and control the gas injection system to connect to the air passage. The described gas injection system firstly solves the nozzle problem. During cold starts, both diesel and gas nozzles inject diesel, increasing the diesel injection volume and reducing the difficulty of cold starts. Secondly, it prevents diesel from entering the gas pipeline. A two-position three-way valve isolates the two fuels. After ignition, the two-position three-way valve returns to its original state, and the gas nozzle resumes its injection function. Simultaneously, a check valve is installed on the first diesel pipeline, located between the two-position three-way valve and the fuel rail. This mechanical check valve prevents gas from entering the fuel line if the two-position three-way valve fails to seal, further improving the sealing performance of the injection system and enhancing safety.

[0017] The beneficial effects of the technical solutions provided in this application include at least the following:

[0018] This invention provides a gas injection system, a starting strategy, and a vehicle. By connecting the diesel pipeline to both the gas and fuel lines simultaneously, during low-temperature starting, the ECU controls the connection of the diesel pipeline to both the gas and fuel lines. Both the fuel and gas lines are used to inject diesel fuel, thereby increasing the amount of diesel fuel injected and reducing the difficulty of starting in low temperatures. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the injection system during normal operation, provided in an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of the injection system during low-temperature start-up provided in an embodiment of the present invention.

[0022] Numbering on the map:

[0023] 1. Diesel injection system; 11. Fuel tank; 12. Filter; 13. Fuel pump; 14. Fuel rail; 2. Gas injection system; 21. Gas cylinder; 22. Buffer tank; 23. Shut-off valve; 24. Balance valve; 25. Gas rail; 3. Injector; 41. First diesel line; 42. Second diesel line; 5. Gas line; 6. ECU; 7. Check valve; 8. Two-position three-way valve. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0025] This application provides a gas injection system, a starting strategy, and a vehicle that can solve the problem in related technologies where the injection valve has few and small oil passages, making it impossible to increase the amount of diesel fuel injected, resulting in difficulty starting at low temperatures.

[0026] Figure 1 and Figure 2 This invention provides a gas injection system, which may include: a diesel injection system 1; a gas injection system 2; a fuel injector 3, which is equipped with an injection valve, the injection valve having an air passage and a fuel passage, the fuel injector 3 being connected to the diesel injection system 1 via a diesel pipeline and to the gas injection system 2 via a gas pipeline 5, the diesel pipeline being connected to the air passage and the fuel passage, and the gas pipeline 5 being connected to the air passage; and an ECU 6, which is used to control the diesel injection system 1 to connect to the air passage and the fuel passage and to cut off the gas pipeline 5 when the engine is in a low-temperature starting condition; and to control the diesel injection system 1 to connect to the fuel passage and the gas injection system 2 to connect to the air passage when the engine is in a normal-temperature starting condition. In this embodiment, when the engine is in a cold start condition, ECU6 controls the diesel injection system 1 to connect to both the air and fuel lines, and disconnects the gas pipeline 5. Both the fuel and air lines are used to inject diesel fuel. When the engine is in a normal temperature start condition, ECU6 controls the diesel injection system 1 to connect to the fuel line and controls the gas injection system 2 to connect to the air line. The air line is used to inject natural gas, and the fuel line is used to inject diesel fuel. Because the diesel pipeline can be connected to both the air and fuel lines simultaneously, during cold starts, ECU6 controls the connection of the diesel pipeline to both the air and fuel lines, so that both the fuel and air lines are used to inject diesel fuel, thereby increasing the amount of diesel fuel injected and reducing the difficulty of cold starts.

[0027] See Figure 1 and Figure 2As shown, in some embodiments, the diesel pipeline includes a first diesel pipeline 41 and a second diesel pipeline 42. The first diesel pipeline 41 is connected to the air circuit, and the second diesel pipeline 42 is connected to the fuel circuit. When the engine is in a cold start condition, the first diesel pipeline 41 is connected to the air circuit; when the engine is in a normal start condition, the first diesel pipeline 41 is disconnected from the air circuit. In this embodiment, by branching off a pipeline downstream of the original diesel injection system's fuel rail and connecting it to the air circuit, when the engine is in a cold start condition, the ECU6 controls the first diesel pipeline 41 to connect to the air circuit, the second diesel pipeline 42 to connect to the fuel circuit, and disconnects the gas pipeline 5. Both the fuel circuit and the air circuit are used to inject diesel fuel. When the engine is in a normal start condition, the second diesel pipeline 42 is controlled to connect to the fuel circuit, the gas pipeline 5 is controlled to connect to the air circuit, and the first diesel pipeline 41 is disconnected. The air circuit is used to inject fuel gas, and the fuel circuit is used to inject diesel fuel. Because the diesel pipeline can be connected to both the air and fuel lines simultaneously, during low-temperature starting, the diesel pipeline is connected to both the air and fuel lines, and both the fuel and air lines are used to inject diesel fuel, thereby increasing the amount of diesel fuel injected and reducing the difficulty of low-temperature starting. The two pipelines are controlled independently, making them convenient to use.

[0028] See Figure 1 and Figure 2 As shown, in some embodiments, the gas injection system includes a two-position three-way valve 8. The two-position three-way valve 8 has a first interface, a second interface, and a third interface. The first interface is connected to the first diesel fuel line 41, the second interface is connected to the gas fuel line 5, and the third interface is connected to the fuel injector 3. In this embodiment, a branch line is branched off from the downstream of the original diesel fuel injection system's fuel rail and connected to one interface of the two-position three-way valve 8. The gas fuel line 5 from the original gas fuel injection system's fuel rail to the fuel injector is connected to the other interface of the two-position three-way valve 8. The two-position three-way valve 8 is activated by the ECU 6 according to commands issued by the engine operating conditions, completing the opening and closing of the two fuels, resulting in precise control and high efficiency. When the engine is in a cold start condition, ECU6 determines that the engine is in a cold start condition. At this time, the two-position three-way valve 8 connects the diesel fuel to the fuel injection valve, the gas line 5 is in the closed state, and the fuel injection valve injects diesel fuel on both sides. When the engine is in a normal temperature start condition, the engine starts successfully, and ECU6 sends a command to the two-position three-way valve 8 to reset. The two-position three-way valve 8 connects the gas fuel to the fuel injection valve, the fuel line is in the closed state, and one of the two injection paths is gas fuel, and the other is diesel fuel for ignition.

[0029] See Figure 1 and Figure 2As shown, in some embodiments, a check valve 7 is installed at the end of the first diesel fuel line 41 near the two-position three-way valve 8. In this embodiment, the two-position three-way valve 8 can isolate two fuels, thereby preventing diesel fuel from entering the gas fuel line 5. At the same time, the check valve 7 is installed on the first diesel fuel line 41. The check valve 7 is located between the two-position three-way valve 8 and the fuel rail 14. The check valve 7 is a mechanical structure, which can prevent gas from entering the fuel line if the two-position three-way valve 8 fails to seal, further improving the sealing performance of the injection system and enhancing safety.

[0030] See Figure 1 and Figure 2 As shown, in some embodiments, the diesel injection system 1 includes a fuel tank 11, a filter 12, a fuel pump 13, and a fuel rail 14 connected in sequence; the gas injection system 2 includes a gas cylinder 21, a buffer tank 22, a shut-off valve 23, a balance valve 24, and a gas rail 25 connected in sequence; the ECU 6 is electrically connected to the shut-off valve 23, the gas rail 25, and the two-position three-way valve 8; and the injector 3 is electrically connected to the fuel rail 14 and the fuel tank 11. In this embodiment, when the engine is in a low-temperature starting condition, diesel injection passes through the fuel tank 11, filter 12, fuel pump 13, fuel rail 14, and two-position three-way valve 8 / injector 3 in sequence. When the engine is in a normal-temperature starting condition, diesel injection passes through the fuel tank 11, filter 12, fuel pump 13, fuel rail 14, and injector 3 in sequence. Gas injection passes through the gas cylinder 21, buffer tank 22, shut-off valve 23, balance valve 24, gas rail 25, two-position three-way valve, and injector 3 in sequence, which is convenient for control.

[0031] See Figure 1 and Figure 2 The diagram illustrates a starting strategy for a gas injection system provided in an embodiment of the present invention. This strategy may include the following steps: determining the engine's starting condition; when the engine is in a low-temperature starting condition, using the ECU 6 to control the connection of the diesel injection system 1 with the air circuit and the fuel circuit, and to disconnect the gas pipeline 5; when the engine is in a normal-temperature starting condition, using the ECU 6 to control the connection of the diesel injection system 1 with the fuel circuit, and to connect the gas injection system 2 with the air circuit. In this embodiment, when the engine is in a low-temperature starting condition, the ECU 6 controls the diesel injection system 1 to connect with the air circuit and the fuel circuit, and disconnects the gas pipeline 5; both the fuel circuit and the air circuit are used to inject diesel fuel. When the engine is in a normal-temperature starting condition, the ECU 6 controls the diesel injection system 1 to connect with the fuel circuit, and controls the gas injection system 2 to connect with the air circuit; the air circuit is used to inject natural gas, and the fuel circuit is used to inject diesel fuel. Because the diesel pipeline can be connected to both the air and fuel lines simultaneously, during cold starts, the ECU6 controls the connection between the diesel pipeline and both the air and fuel lines, so that both the fuel and air lines are used to inject diesel fuel, thereby increasing the amount of diesel fuel injected and reducing the difficulty of cold starts.

[0032] See Figure 1 and Figure 2 As shown, in some embodiments, the diesel pipeline includes a first diesel pipeline 41 and a second diesel pipeline 42. The first diesel pipeline 41 is connected to the air circuit, and the second diesel pipeline 42 is connected to the fuel circuit. When the engine is in a cold start condition, the ECU 6 controls the connection between the first diesel pipeline 41 and the air circuit. When the engine is in a normal start condition, the ECU 6 controls the disconnection between the first diesel pipeline 41 and the air circuit. In this embodiment, a branch is drawn from the downstream pipeline of the original diesel injection system's fuel rail and connected to the air circuit. When the engine is in a cold start condition, the ECU 6 controls the first diesel pipeline 41 to connect to the air circuit, the second diesel pipeline 42 to connect to the fuel circuit, and disconnects the gas pipeline 5. Both the fuel circuit and the air circuit are used to inject diesel fuel. When the engine is in a normal start condition, the second diesel pipeline 42 is controlled to connect to the fuel circuit, the gas pipeline 5 is controlled to connect to the air circuit, and the first diesel pipeline 41 is disconnected. The air circuit is used to inject fuel gas, and the fuel circuit is used to inject diesel fuel. Because the diesel pipeline can be connected to both the air and fuel lines simultaneously, during low-temperature starting, the diesel pipeline is connected to both the air and fuel lines, and both the fuel and air lines are used to inject diesel fuel, thereby increasing the amount of diesel fuel injected and reducing the difficulty of low-temperature starting. The two pipelines are controlled independently, making them convenient to use.

[0033] See Figure 1 and Figure 2 As shown, in some embodiments, the step of using the ECU6 to control the connection of the diesel injection system 1 with the air circuit and the oil circuit, and to cut off the gas pipeline 5 includes: when the ambient temperature is <0℃, the engine coolant temperature is <5℃, and the engine speed is <550rpm, it is determined that the engine is in a low-temperature start-up condition, and the ECU6 controls the two-position three-way valve 8 to connect the first diesel pipeline 41 with the air circuit and to cut off the gas pipeline 5.

[0034] See Figure 1 and Figure 2 As shown, in some embodiments, the step of using the ECU6 to control the connection of the diesel injection system 1 to the fuel line and the gas injection system 2 to the gas line includes: when the engine speed is >550 rpm, it is determined that the engine has started successfully, and the ECU6 controls the two-position three-way valve 8 to connect the gas injection system 2 to the gas line and disconnect the first diesel line 41 from the gas line.

[0035] This invention also provides a vehicle including the aforementioned gas injection system. The gas injection system may include: a diesel injection system 1; a gas injection system 2; a fuel injector 3 equipped with an injection valve, the injection valve having an air passage and a fuel passage; the fuel injector 3 connected to the diesel injection system 1 via a diesel pipeline and to the gas injection system 2 via a gas pipeline 5, the diesel pipeline connecting the air passage and the fuel passage, and the gas pipeline 5 connecting the air passage; and an ECU 6, used to control the diesel injection system 1 to connect to the air passage and the fuel passage, and to cut off the gas pipeline 5, when the engine is in a low-temperature starting condition; and to control the diesel injection system 1 to connect to the fuel passage and the gas injection system 2 to connect to the air passage when the engine is in a normal-temperature starting condition. The gas injection system firstly solves the nozzle problem. During low-temperature starting, both diesel and gas nozzles inject diesel, increasing the diesel injection volume and reducing the difficulty of starting at low temperatures. Secondly, it prevents diesel from entering the gas pipeline by using a two-position three-way valve 8 to isolate the two fuels. After starting and ignition, the two-position three-way valve 8 returns to its original state, and the gas nozzle resumes its injection function. At the same time, a check valve 7 is installed on the first diesel pipeline 41. The check valve 7 is located between the two-position three-way valve 8 and the fuel rail 14. The check valve 7 is a mechanical structure that prevents gas from entering the fuel line if the two-position three-way valve 8 fails to seal, further improving the sealing performance of the injection system and enhancing safety.

[0036] Specifically, such as Figure 1 As shown, a branch line is split from the downstream of the original diesel injection system's fuel rail, connecting one of the interfaces of the check valve 7 and the two-position three-way valve 8; the original gas injection system's fuel rail to injector line is connected to the other inlet of the aforementioned two-position three-way valve 8. Only the two-position three-way valve 8, the diesel fuel line, and the check valve 7 are added to the gas fuel line. The two-position three-way valve is activated by the ECU according to commands issued by the engine operating conditions, completing the opening and closing of the two fuels. The check valve 7 is a mechanical structure to prevent gas from entering the fuel line if the two-position three-way valve 8 fails to seal.

[0037] like Figure 2 As shown, when the ambient temperature is <0℃, the engine coolant temperature is <5℃, and the engine speed is <550rpm, the ECU6 determines that the engine is in a low-temperature start-up condition. At this time, the two-position three-way valve 8 connects the diesel fuel to the fuel line of the injection valve, while the gas line 5 is in a closed state; both lines of the injection valve inject diesel fuel.

[0038] like Figure 1 As shown, when the engine speed is >550rpm, the engine starts successfully. The ECU6 sends a command to reset the two-position three-way valve 8. The two-position three-way valve 8 connects the gas path from the fuel gas to the injection valve, while the fuel path is cut off. One of the two injection paths is fuel gas, and the other is diesel fuel for ignition.

[0039] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship 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, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" 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 connection within two components. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0040] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0041] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this 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 this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A gas injection system, characterized in that, It includes: Diesel injection system (1); Gas injection system (2); The injector (3) is provided with an injection valve, which is provided with an air passage and an oil passage. The injector (3) is connected to the diesel injection system (1) through a diesel pipeline and to the gas injection system (2) through a gas pipeline (5). The diesel pipeline is connected to the air passage and the oil passage, and the gas pipeline (5) is connected to the air passage. ECU (6) is used to control the diesel injection system (1) to connect with the air circuit and the oil circuit and to cut off the gas pipeline (5) when the engine is in a low temperature starting condition; and to control the diesel injection system (1) to connect with the oil circuit and the gas injection system (2) to connect with the air circuit when the engine is in a normal temperature starting condition. The diesel pipeline includes a first diesel pipeline (41) and a second diesel pipeline (42), the first diesel pipeline (41) being connected to the gas line and the second diesel pipeline (42) being connected to the oil line; When the engine is in a low-temperature start-up condition, the first diesel pipeline (41) is connected to the gas pipeline; When the engine is in normal temperature starting condition, the first diesel pipeline (41) and the gas pipeline are disconnected.

2. The gas injection system as described in claim 1, characterized in that: The gas injection system includes a two-position three-way valve (8), which has a first interface, a second interface and a third interface. The first interface is connected to the first diesel pipeline (41), the second interface is connected to the gas pipeline (5), and the third interface is connected to the fuel injector (3).

3. The gas injection system as described in claim 2, characterized in that: A check valve (7) is installed at one end of the first diesel pipeline (41) near the two-position three-way valve (8).

4. The gas injection system as described in claim 2, characterized in that: The diesel injection system (1) includes a fuel tank (11), a filter (12), a fuel pump (13), and a fuel rail (14) connected in sequence; the gas injection system (2) includes a gas cylinder (21), a buffer tank (22), a shut-off valve (23), a balance valve (24), and a gas rail (25) connected in sequence. The ECU (6) is electrically connected to the shut-off valve (23), the air rail (25) and the two-position three-way valve (8), and the injector (3) is electrically connected to the fuel rail (14) and the fuel tank (11).

5. A startup strategy for a gas injection system as described in claim 1, characterized in that, It includes the following steps: Determine the engine's starting condition; When the engine is in a low-temperature starting condition, the ECU (6) controls the connection of the diesel injection system (1) with the gas line and the oil line, and cuts off the gas pipeline (5); when the engine is in a normal temperature starting condition, the ECU (6) controls the connection of the diesel injection system (1) with the oil line, and the connection of the gas injection system (2) with the gas line. The diesel pipeline includes a first diesel pipeline (41) and a second diesel pipeline (42), the first diesel pipeline (41) being connected to the gas line and the second diesel pipeline (42) being connected to the oil line; When the engine is in a low-temperature start-up condition, the ECU (6) controls the connection between the first diesel pipeline (41) and the air circuit; When the engine is in normal temperature starting condition, the ECU (6) controls the cut-off of the first diesel pipeline (41) and the air pipeline; The method of using the ECU (6) to control the connection of the diesel injection system (1) with the gas circuit and the fuel circuit, and to disconnect the gas pipeline (5) includes: When the ambient temperature is <0℃, the engine coolant temperature is <5℃, and the engine speed is <550rpm, the engine is judged to be in a low-temperature start-up condition. The ECU (6) controls the two-position three-way valve (8) to connect the first diesel pipeline (41) and the gas pipeline, and cut off the gas pipeline (5). The step of using the ECU (6) to control the connection of the diesel injection system (1) to the fuel line and the gas injection system (2) to the gas line includes: When the engine speed is greater than 550 rpm, the engine is judged to have started successfully. The ECU (6) controls the two-position three-way valve (8) to connect the gas injection system (2) and the gas circuit, and cut off the first diesel pipeline (41) and the gas circuit.

6. A vehicle, characterized in that, It includes the gas injection system as described in any one of claims 1 to 4.

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