Dual-fuel supply system, control method thereof and dual-fuel engine

Abstract

The invention relates to the technical field of engines, and particularly discloses a dual-fuel supply system, a control method thereof and a dual-fuel engine, the dual-fuel supply system comprises a first fuel supply device and a second fuel supply device, the first fuel supply device is provided with an oil pump and a composite oil rail, and the composite oil rail comprises a high-pressure oil rail and a pressure regulating valve; an outlet of the high-pressure oil rail is communicated with a first fuel inlet of the fuel injector, the second fuel supply device is provided with an electric pressure control valve and a high-pressure gas rail, an outlet of the high-pressure gas rail is communicated with a second fuel inlet of the fuel injector, and an outlet of the pressure regulating valve is communicated with a control oil port of the fuel injector. And a control valve for opening or closing the fuel injector. The high-pressure oil rail and the pressure regulating valve are combined into the composite oil rail, fuel oil and control oil can be supplied to the fuel injector only through one oil pump, compared with the prior art, one oil pump and a corresponding pipeline are omitted, the structural complexity is lowered, and occupied space of an engine compartment is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and in particular to a dual-fuel supply system, a control method thereof and a dual-fuel engine. Background Art

[0002] Dual-fuel engines generally use liquid fuel and gas fuel, and independent supply systems are provided for liquid fuel and gas fuel respectively, which are used to supply fuel to the fuel injector. The fuel injector injects fuel into the combustion chamber by controlling the oil, which is specifically reflected in the oil of the control oil entering the control oil port of the fuel injector and pushing the control valve of the fuel injector to make it open or cut off, so as to realize the injection of the controlled fuel injector. The control oil in the prior art requires a separate oil circuit system, so the supply system of the dual-fuel engine requires at least two oil pumps for supplying fuel and control oil respectively, which has a complex structure and occupies a large space in the engine compartment. Summary of the invention

[0003] The object of the present invention is to provide a dual-fuel supply system, a control method thereof and a dual-fuel engine to solve the problem of a large number of parts in the existing fuel cell air system.

[0004] The present invention provides a dual fuel supply system, comprising a fuel injector, the fuel injector is used to inject fuel into a combustion chamber, and also comprises a first fuel supply device and a second fuel supply device, the first fuel supply device is provided with an oil pump and a composite oil rail, the oil pump is used to pump oil into the composite oil rail, the composite oil rail comprises a high-pressure oil rail and a pressure regulating valve, the outlet of the high-pressure oil rail is communicated with a first fuel inlet of the fuel injector, and can supply fuel to the first fuel inlet, the second fuel supply device is provided with an electric pressure control valve and a high-pressure gas rail, the electric pressure control valve is used to change the pressure of the gas fuel in the high-pressure gas rail, the outlet of the high-pressure gas rail is communicated with the second fuel inlet of the fuel injector, and can supply gas fuel to the second fuel inlet, the inlet of the pressure regulating valve is communicated with the high-pressure oil rail, and the outlet is communicated with the control oil port of the fuel injector, and is used to conduct or cut off the control valve of the fuel injector.

[0005] As a preferred technical solution of the dual fuel supply system, it also includes a first sensor and a second sensor, the first sensor is used to measure the pressure and temperature values ​​at the outlet of the high-pressure fuel rail, and the second sensor is used to measure the pressure and temperature values ​​at the outlet of the pressure regulating valve.

[0006] As a preferred technical solution of the dual-fuel supply system, a third sensor is also included, and the third sensor is used to measure the pressure value and temperature value at the outlet of the high-pressure gas rail.

[0007] As a preferred technical solution of the dual fuel supply system, a fuel injector is provided on the communication path between the high-pressure fuel rail and the fuel injector, and the fuel injector is used to open or close the communication flow path between the high-pressure fuel rail and the fuel injector.

[0008] As a preferred technical solution for the dual fuel supply system, it also includes an ECU, and the first sensor, the second sensor, the third sensor, the oil pump and the electric pressure control valve are all communicatively connected to the ECU. The oil pump can change the pumping power according to the pressure value and temperature value measured by the first sensor and / or the second sensor, and the electric pressure control valve can change the opening according to the pressure value and temperature value measured by the third sensor.

[0009] The present invention provides a control method for a dual fuel supply system, which is applied to the dual fuel supply system of any of the above schemes. The control method for the dual fuel supply system includes:

[0010] Selecting a fuel supply mode, wherein the fuel supply mode includes a fuel supply mode alone, a gas supply mode alone, and a mixed supply mode;

[0011] The first fuel supply device and / or the second fuel supply device is selected to supply fuel to the fuel injector according to the selected fuel supply mode.

[0012] As a preferred technical solution of the control method of the dual fuel supply system, when the fuel supply mode is selected as the single fuel supply mode:

[0013] The oil pump supplies oil to the composite oil rail;

[0014] Adjust the oil pump power so that the oil pressure in the high-pressure oil rail is within the preset injection pressure range;

[0015] The pressure regulating valve supplies control oil to the fuel injector, thereby conducting the control valve of the fuel injector;

[0016] The high-pressure rail supplies fuel to the fuel injectors;

[0017] The fuel injectors spray fuel into the combustion chambers.

[0018] As a preferred technical solution of the control method of the dual fuel supply system, when the fuel supply mode is selected as the single gas supply mode:

[0019] The oil pump supplies oil to the composite oil rail, and the electric pressure control valve opens to supply gas to the high-pressure gas rail;

[0020] Adjust the opening of the electric pressure control valve so that the air pressure in the high-pressure air rail is within the preset injection pressure range;

[0021] Adjust the oil pump power so that the pressure at the outlet of the pressure regulating valve is greater than the air pressure in the high-pressure air rail;

[0022] The pressure regulating valve supplies control oil to the fuel injector, thereby conducting the control valve of the fuel injector;

[0023] A high pressure gas rail supplies gaseous fuel to the fuel injectors;

[0024] The fuel injectors inject gaseous fuel into the combustion chambers.

[0025] As a preferred technical solution of the control method of the dual fuel supply system, when the fuel supply mode is selected as the mixed supply mode:

[0026] The oil pump supplies oil to the composite oil rail, and the electric pressure control valve opens to supply gas to the high-pressure gas rail;

[0027] Adjust the oil pump power so that the oil pressure in the high-pressure oil rail is within the preset injection pressure range;

[0028] The pressure regulating valve supplies control oil to the fuel injector, thereby conducting the control valve of the fuel injector;

[0029] Adjust the opening of the electric pressure control valve so that the air pressure in the high-pressure rail is less than the pressure at the outlet of the pressure regulating valve;

[0030] The fuel injectors spray oil and gaseous fuel into the combustion chambers.

[0031] The present invention provides a dual-fuel engine, including the dual-fuel supply system of the above solution or a control method of the dual-fuel supply system using the above solution.

[0032] The beneficial effects of the present invention are:

[0033] The present invention provides a dual fuel supply system, which combines a high-pressure oil rail and a pressure regulating valve into a composite oil rail, so that only one oil pump is used to supply fuel and control oil to a fuel injector. Compared with the prior art, one oil pump and corresponding pipelines are reduced, the structural complexity is reduced, and the space occupied by the engine compartment is reduced.

[0034] The present invention provides a control method for a dual-fuel supply system. By setting the dual-fuel supply system of the present invention, under the premise of satisfying different fuel supply modes, the setting of the composite fuel rail makes the control process more convenient.

[0035] The present invention provides a dual-fuel engine, which reduces cost and space occupation and makes the control process simpler by providing a dual-fuel supply system or using a control method of the dual-fuel supply system in the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of the principle of a dual fuel supply system in an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of the principle of a composite oil rail in an embodiment of the present invention;

[0038] Figure 3 A flow chart of a dual fuel supply system operating in a single fuel supply mode in an embodiment of the present invention;

[0039] Figure 4 A flow chart of a dual fuel supply system operating in a single gas supply mode in an embodiment of the present invention;

[0040] Figure 5 FIG. 4 is a flow chart of a dual fuel supply system operating in a mixed supply mode according to an embodiment of the present invention.

[0041] In the figure:

[0042] 11. High-pressure gas source; 12. Electric pressure control valve; 13. High-pressure gas rail; 21. Fuel tank; 22. Fuel pump; 23. Composite fuel rail; 231. High-pressure fuel rail; 232. Pressure regulating valve; 3. ECU; 4. Fuel injector; 5. Combustion chamber; 61. First sensor; 62. Second sensor; 63. Third sensor. DETAILED DESCRIPTION

[0043] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying 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 limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature "above", "above" and "above" the second feature include the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature include the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0045] In the description of the present invention, it should be noted that, 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0047] like Figure 1-Figure 2As shown, the present invention provides a dual fuel supply system for a dual fuel engine, which includes a fuel injector 4, and the fuel injector 4 is used to inject fuel into a combustion chamber 5, which can be a liquid fuel such as fuel oil, or a gaseous fuel such as natural gas or petroleum gas. According to the actual working condition of the engine, the fuel injector 4 can only inject fuel or gaseous fuel into the combustion chamber 5, or the fuel injector 4 can simultaneously inject fuel and gaseous fuel into the combustion chamber 5. The fuel injector 4 is a structure in the prior art and is not described in detail herein. The dual fuel supply system also includes a first fuel supply device and a second fuel supply device. The first fuel supply device is used to supply fuel to the fuel injector 4, and the second fuel supply device is used to supply gaseous fuel to the fuel injector 4. In this embodiment, the fuel can be gasoline or diesel, preferably diesel; the gaseous fuel can be natural gas, petroleum gas or biomass gas, preferably natural gas. The first fuel supply device is provided with an oil pump 22 and a composite oil rail 23, the inlet of the oil pump 22 is connected to the oil tank 21, and the outlet of the oil pump 22 is connected to the composite oil rail 23, and the oil pump 22 is used to extract fuel from the oil tank 21 and pump oil to the composite oil rail 23. The composite oil rail 23 includes a high-pressure oil rail 231 and a pressure regulating valve 232. The pressure regulating valve 232 is connected to the end of the high-pressure oil rail 231. The outlet of the high-pressure oil rail 231 is connected to the first fuel inlet of the fuel injector 4, and can supply fuel to the first fuel inlet. The second fuel supply device is provided with an electric pressure control valve 12 and a high-pressure gas rail 13. The electric pressure valve is arranged between the high-pressure gas rail 13 and the flow path of the high-pressure gas source 11. The electric pressure control valve 12 is used to change the pressure of the gas fuel in the high-pressure gas rail 13. The outlet of the high-pressure gas rail 13 is connected to the second fuel inlet of the fuel injector 4, and can supply gas fuel to the second fuel inlet. The inlet of the pressure regulating valve 232 is connected to the high-pressure oil rail 231, and the outlet is connected to the control oil port of the fuel injector 4. The pressure regulating valve 232 can adjust the pressure difference between the pressure at the outlet and the pressure at the inlet by adjusting the preload of the internal spring, so that the oil pressure entering the control oil port of the fuel injector 4 from the outlet of the pressure regulating valve 232 is variable, so it can be used to conduct or cut off the control valve of the fuel injector 4. Those skilled in the art can also set the pressure regulating valve 232 as a proportionally adjustable boost valve or pressure reducing valve in the prior art as needed. The high-pressure oil rail 231 and the pressure regulating valve 232 in this embodiment together form a composite oil rail 23, so the oil flowing from the pressure regulating valve 232 to the control oil port of the fuel injector 4 is fuel, and a related return oil pipeline is set so that the fuel can flow back to the fuel tank 21. When the control valve of the fuel injector 4 is turned on, the fuel injector 4 receives the injection command transmitted by the ECU3 and injects the fuel supplied by the first fuel supply device and / or the second fuel supply device into the combustion chamber 5 of the engine.

[0048] In this embodiment, the high-pressure oil rail 231 and the pressure regulating valve 232 are combined into a composite oil rail 23, so that only one oil pump 22 is used to supply fuel and control oil to the fuel injector 4. Compared with the prior art, one oil pump 22 and the corresponding pipeline are reduced, the structural complexity is reduced, and the space occupied by the engine compartment is reduced.

[0049] Furthermore, the composite oil rail 23 is also connected with a first sensor 61 and a second sensor 62, and the first sensor 61 and the second sensor 62 are both configured as pressure sensors or temperature pressure sensors. In this embodiment, the first sensor 61 and the second sensor 62 are preferably temperature pressure sensors. The first sensor 61 is used to measure the pressure and temperature values ​​inside or at the outlet of the high-pressure oil rail 231, and the second sensor 62 is used to measure the pressure and temperature values ​​at the outlet of the pressure regulating valve 232. The first sensor 61 and the second sensor 62 are configured to measure the pressure and temperature values ​​at the outlet of the high-pressure oil rail 231 and the pressure regulating valve 232, respectively, so as to adapt to the power adjustment of the oil pump 22 to ensure that the pressure and temperature values ​​at the outlet of the high-pressure oil rail 231 and the pressure regulating valve 232 meet the working requirements. A third sensor 63 is also provided on the high-pressure gas rail 13, and the third sensor 63 is used to measure the pressure and temperature values ​​inside or at the outlet of the high-pressure gas rail 13, so as to further adjust the opening of the electric pressure control valve 12, change the pressure and temperature values ​​inside the high-pressure gas rail 13, and ensure that the pressure and temperature values ​​inside the high-pressure gas rail 13 meet the working requirements.

[0050] It is understandable that no matter how the fuel injector 4 operates, the oil pump 22 always pumps oil into the composite oil rail 23, that is, the fuel in the high-pressure oil rail 231 always maintains a certain oil pressure, so that the oil at the outlet of the pressure regulating valve 232 can control the fuel injector 4. Therefore, a fuel injector is provided on the communication path between the high-pressure oil rail 231 and the fuel injector 4, and the fuel injector is used to conduct or cut off the communication flow path between the high-pressure oil rail 231 and the fuel injector 4. By providing the fuel injector, it is avoided that the high-pressure oil rail 231 additionally supplies fuel when the gas fuel is supplied alone. Similarly, in order to avoid the high-pressure gas rail 13 additionally supplies gas fuel to the fuel injector 4 when the fuel is supplied alone, a gas injector can also be provided between the high-pressure gas rail 13 and the fuel injector 4, and the gas injector is used to conduct or cut off the communication flow path between the high-pressure gas rail 13 and the fuel injector 4.

[0051] Specifically, the dual fuel supply system further includes an ECU3, and the first sensor 61, the second sensor 62, the third sensor 63, the oil pump 22, the electric pressure control valve 12, the fuel tank 21 and the high pressure gas source 11 are all connected to the ECU3 in communication. The oil pump 22 can change the pumping power according to the pressure value and temperature value measured by the first sensor 61 and / or the second sensor 62, thereby changing the fuel pressure in the high pressure oil rail 231 and changing the pressure at the outlet of the pressure regulating valve 232. The electric pressure control valve 12 can change the opening according to the pressure value and temperature value measured by the third sensor 63, thereby changing the pressure of the gas fuel in the high pressure gas rail 13. A fuel level sensing device is provided in the fuel tank 21, so as to give an alarm in time when the fuel is insufficient and switch the fuel supply mode to only supply gas fuel to avoid power interruption. A pressure sensing device is provided in the high pressure gas source 11, so as to give an alarm in time when the gas fuel pressure value in the high pressure gas source 11 is insufficient and switch the fuel supply mode to only supply fuel to avoid power interruption.

[0052] The present invention provides a control method for a dual fuel supply system, which is applied to the dual fuel supply system in this embodiment. The control method for the dual fuel supply system includes the following steps:

[0053] Selecting a fuel supply mode, the fuel supply mode includes a separate oil supply mode, a separate gas supply mode and a mixed supply mode;

[0054] After the fuel supply mode is selected, the ECU 3 sends a corresponding control signal and selects the first fuel supply device and / or the second fuel supply mode to supply fuel to the fuel injector 4 according to the selected fuel supply mode.

[0055] The switch can be made manually or automatically by the driving computer according to factors such as the load and power demand under the current vehicle driving condition. When the single fuel supply mode is selected, only the first fuel supply device supplies fuel to the fuel injector 4; when the single gas supply mode is selected, only the second fuel supply device supplies gas fuel to the fuel injector 4; when the mixed supply mode is selected, the first fuel supply device supplies fuel to the fuel injector 4, and the second fuel supply device supplies gas fuel to the fuel injector 4.

[0056] Specifically, Figure 3 As shown, when the fuel supply mode is selected as the single fuel supply mode, the control method of the dual fuel supply system includes the following steps:

[0057] ECU3 sends out a fuel injection signal;

[0058] The oil pump 22 supplies oil to the composite oil rail 23;

[0059] The power of the oil pump 22 is adjusted according to the pressure value and the temperature value measured by the first sensor 61 and the second sensor 62, so that the oil pressure in the high-pressure oil rail 231 is within the preset injection pressure range, and at the same time, the pressure at the outlet of the pressure regulating valve 232 is able to open the control valve of the fuel injector 4;

[0060] The pressure regulating valve 232 supplies control oil to the fuel injector 4, thereby conducting the control valve of the fuel injector 4;

[0061] The fuel injector is opened, and the high pressure fuel rail 231 supplies fuel to the fuel injector 4;

[0062] The fuel injector 4 injects fuel into the combustion chamber 5 .

[0063] The preset injection pressure range is determined by the on-board computer according to the current working conditions and the engine calibration program. The relevant internals belong to the prior art in this field and are not specifically limited here. When the fuel supply mode is selected as the single fuel supply mode, the jet nozzle cuts off the communication flow path between the high-pressure gas rail 13 and the fuel injector 4, and the electric pressure control valve 12 is in an open state but does not adjust the opening to ensure that when the fuel supply mode is switched, the high-pressure gas rail 13 can immediately supply gas fuel to the fuel injector 4 to avoid power interruption or delay.

[0064] Specifically, Figure 4 As shown, when the fuel supply mode is selected as the single gas supply mode, the control method of the dual fuel supply system includes the following steps:

[0065] ECU3 sends out an injection signal;

[0066] The oil pump 22 supplies oil to the composite oil rail 23, and the electric pressure control valve 12 opens to supply gas to the high-pressure gas rail 13;

[0067] According to the pressure value and temperature value measured by the third sensor 63, the opening of the electric pressure control valve 12 is adjusted so that the air pressure in the high-pressure air rail 13 is within the preset injection pressure range;

[0068] The power of the oil pump 22 is adjusted according to the pressure value and temperature value at the outlet of the pressure regulating valve 232 measured by the second sensor 62, so that the pressure value at the outlet of the pressure regulating valve 232 is greater than the air pressure value in the high-pressure air rail 13 measured by the third sensor 63;

[0069] The pressure regulating valve 232 supplies control oil to the fuel injector 4, thereby conducting the control valve of the fuel injector 4;

[0070] The jet nozzle opens, and the high-pressure gas rail 13 supplies gaseous fuel to the fuel injector 4;

[0071] The fuel injector 4 injects gaseous fuel into the combustion chamber 5 .

[0072] The preset injection pressure range is determined by the driving computer according to the current working conditions and the engine calibration program. The relevant internal parts belong to the existing technology in this field and are not specifically limited here. Making the pressure value at the outlet of the pressure regulating valve 232 greater than the air pressure value in the high-pressure gas rail 13 measured by the third sensor 63 can ensure that the air pressure value of the gas fuel supplied to the fuel injector 4 is less than the pressure value of the control oil of the fuel injector 4, and prevent the gas fuel from entering the pressure regulating valve 232 and the high-pressure oil rail 231 along the control pipeline. In the process of selecting the fuel supply mode as the single air supply mode, the fuel injector cuts off the communication flow path between the high-pressure oil rail 231 and the fuel injector 4, and the gas fuel burns and works by compression ignition. The oil pump 22 is always turned on, on the one hand, to provide pressure for the pressure regulating valve 232, and on the other hand, to ensure that when the fuel supply mode is switched, the high-pressure oil rail 231 can immediately supply fuel to the fuel injector 4 to avoid power interruption or delay. In other embodiments, the fuel injector may not be completely closed, so that a small amount of fuel will enter the combustion chamber 5 together with the gas fuel. The fuel will burn first and ignite the gas fuel. In this process, the fuel is only used to ignite the gas fuel and will not affect the power characteristics of the engine under this fuel supply mode.

[0073] Specifically, Figure 5 As shown, when the fuel supply mode is selected as the mixed supply mode, the control method of the dual fuel supply system includes the following steps:

[0074] ECU3 sends out fuel injection and air jet signals;

[0075] The oil pump 22 supplies oil to the composite oil rail 23, and the electric pressure control valve 12 opens to supply gas to the high-pressure gas rail 13;

[0076] The power of the oil pump 22 is adjusted according to the pressure value and the temperature value measured by the first sensor 61 and the second sensor 62, so that the oil pressure in the high-pressure oil rail 231 is within the preset injection pressure range, and at the same time, the pressure at the outlet of the pressure regulating valve 232 is able to open the control valve of the fuel injector 4;

[0077] The pressure regulating valve 232 supplies control oil to the fuel injector 4, thereby conducting the control valve of the fuel injector 4;

[0078] The opening of the electric pressure control valve 12 is adjusted according to the pressure value and temperature value measured by the third sensor 63, so that the air pressure value in the high-pressure air rail 13 measured by the third sensor 63 is less than the pressure value at the outlet of the pressure regulating valve 232;

[0079] The fuel injector is opened, the air injector is opened, and the high-pressure oil rail 231 and the high-pressure gas rail 13 supply fuel oil and gas fuel to the fuel injector 4 respectively;

[0080] The fuel injector 4 injects fuel oil and gas fuel into the combustion chamber 5 .

[0081] The air pressure value in the high-pressure gas rail 13 measured by the third sensor 63 is made smaller than the pressure value at the outlet of the pressure regulating valve 232, so as to ensure that the air pressure value of the gas fuel supplied to the fuel injector 4 is smaller than the pressure value of the control oil of the fuel injector 4, and to prevent the gas fuel from entering the pressure regulating valve 232 and the high-pressure oil rail 231 along the control pipeline. In the mixed supply mode, the fuel oil and the gas fuel can be mixed in any proportion to enter the combustion chamber 5 for combustion by adjusting the power of the oil pump 22 and the opening of the electric pressure control valve 12 respectively, and combining with changing the opening time of the fuel injector and the air jet nozzle, so as to take into account both the power and fuel economy of the engine.

[0082] The present invention provides a dual-fuel engine, including the dual-fuel supply system of the present embodiment or the method of using the dual-fuel supply system of the present embodiment. By setting the dual-fuel supply system of the present embodiment or the control method of using the dual-fuel supply system, the cost and space occupation are reduced, and the control process is simpler.

[0083] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A dual fuel supply system comprising a fuel injector (4) for injecting fuel into a combustion chamber (5), characterized in that: Also includes: A first fuel supply device and a second fuel supply device, wherein the first fuel supply device is provided with an oil pump (22) and a composite oil rail (23), wherein the oil pump (22) is used to pump oil to the composite oil rail (23), wherein the composite oil rail (23) comprises a high-pressure oil rail (231) and a pressure regulating valve (232), wherein the outlet of the high-pressure oil rail (231) is connected to a first fuel inlet of the fuel injector (4) and can supply fuel to the first fuel inlet, and the second fuel supply device is provided with an electric pressure control valve (12) and a high-pressure gas rail (13), wherein the electric pressure control valve (12) is used to change the pressure of the gas fuel in the high-pressure gas rail (13), wherein the outlet of the high-pressure gas rail (13) is connected to a second fuel inlet of the fuel injector (4) and can supply gas fuel to the second fuel inlet, wherein the inlet of the pressure regulating valve (232) is connected to the high-pressure oil rail (231), and the outlet is connected to a control oil port of the fuel injector (4), and is used to open or close the control valve of the fuel injector (4).

2. The dual fuel supply system according to claim 1, characterized in that: It also includes a first sensor (61) and a second sensor (62), wherein the first sensor (61) is used to measure the pressure and temperature values ​​at the outlet of the high-pressure oil rail (231), and the second sensor (62) is used to measure the pressure and temperature values ​​at the outlet of the pressure regulating valve (232).

3. The dual fuel supply system according to claim 2, characterized in that: It also comprises a third sensor (63), wherein the third sensor (63) is used to measure the pressure value and the temperature value at the outlet of the high-pressure gas rail (13).

4. The dual fuel supply system according to claim 3, characterized in that: A fuel injection nozzle is provided on the communication path between the high-pressure fuel rail (231) and the fuel injector (4), and the fuel injection nozzle is used to open or cut off the communication flow path between the high-pressure fuel rail (231) and the fuel injector (4).

5. The dual fuel supply system according to claim 4, characterized in that: The invention also includes an ECU (3), wherein the first sensor (61), the second sensor (62), the third sensor (63), the oil pump (22) and the electric pressure control valve (12) are all connected to the ECU (3) for communication, and the oil pump (22) can change the oil pumping power according to the pressure value and temperature value measured by the first sensor (61) and / or the second sensor (62), and the electric pressure control valve (12) can change the opening according to the pressure value and temperature value measured by the third sensor (63).

6. A control method for a dual fuel supply system, characterized in that: Applied to the dual fuel supply system according to any one of claims 1 to 5, the control method of the dual fuel supply system comprises: Selecting a fuel supply mode, wherein the fuel supply mode includes a fuel supply mode alone, a gas supply mode alone, and a mixed supply mode; The first fuel supply device and / or the second fuel supply device is selected to supply fuel to the fuel injector (4) according to the selected fuel supply mode.

7. The control method of the dual fuel supply system according to claim 6, characterized in that: When the fuel supply mode is selected as the single fuel supply mode: The oil pump (22) supplies oil to the composite oil rail (23); Adjusting the power of the oil pump (22) so that the oil pressure in the high-pressure oil rail (231) is within a preset injection pressure range; The pressure regulating valve (232) supplies control oil to the fuel injector (4) to open the control valve of the fuel injector (4); The high pressure fuel rail (231) supplies fuel to the fuel injector (4); The fuel injector (4) injects fuel into the combustion chamber (5).

8. The control method of the dual fuel supply system according to claim 6, characterized in that: When the fuel supply mode is selected as the separate air supply mode: The oil pump (22) supplies oil to the composite oil rail (23), and the electric pressure control valve (12) opens to supply gas to the high-pressure gas rail (13); Adjusting the opening of the electric pressure control valve (12) so that the air pressure in the high-pressure air rail (13) is within a preset jet pressure range; Adjusting the power of the oil pump (22) so that the pressure value at the outlet of the pressure regulating valve (232) is greater than the air pressure value in the high-pressure air rail (13); The pressure regulating valve (232) supplies control oil to the fuel injector (4) to open the control valve of the fuel injector (4); The high pressure gas rail (13) supplies gaseous fuel to the fuel injector (4); The fuel injector (4) injects gaseous fuel into the combustion chamber (5).

9. The control method of the dual fuel supply system according to claim 6, characterized in that: When the fuel supply mode is selected as the mixed supply mode: The oil pump (22) supplies oil to the composite oil rail (23), and the electric pressure control valve (12) opens to supply gas to the high-pressure gas rail (13); Adjusting the power of the oil pump (22) so that the oil pressure in the high-pressure oil rail (231) is within a preset injection pressure range; The pressure regulating valve (232) supplies control oil to the fuel injector (4) to open the control valve of the fuel injector (4); Adjusting the opening of the electric pressure control valve (12) so that the air pressure value in the high-pressure air rail (13) is less than the pressure value at the outlet of the pressure regulating valve (232); The fuel injector (4) injects fuel oil and gaseous fuel into the combustion chamber (5).

10. A dual fuel engine, characterized in that: A dual fuel supply system comprising any one of claims 1 to 5 or a control method using the dual fuel supply system according to any one of claims 6 to 9.

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