Dual fuel injection system, control method, control device, and vehicle

Abstract

The application belongs to the technical field of vehicles, and discloses a dual-fuel injection system, a control method, a control device and a vehicle. In the working process of the engine, the dual-fuel injection system adjusts the injection pressure of the first fuel according to the speed and torque of the engine to ensure that the injection amount of the first fuel meets the basic requirements of the engine operation, and limits P1>P2 so that the accumulated carbon at the injection hole can be washed away when the first fuel is injected, the injection hole is prevented from being blocked, and thus the first fuel injection channel can normally inject the first fuel into the combustion chamber. The dual-fuel injection system control method can avoid waste of the first fuel, improve the economy of the engine operation, and at the same time, can reduce the influence of the first fuel injection on the engine performance as much as possible on the premise of ensuring that the accumulated carbon at the injection hole is washed away.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and in particular to a dual-fuel injection system, control method, control device, and vehicle. Background Technology

[0002] A dual-fuel injector's injection tip extends directly into the combustion chamber. It injects two fuels into the combustion chamber: one is an ignition fuel, and the other is the main fuel, which is used to ignite the main fuel. When the ignition fuel is gasoline or diesel, the injection tip is constantly exposed to high temperatures. The nozzle orifice used for injecting the ignition fuel is relatively small and prone to carbon buildup. Furthermore, to improve fuel economy, the injection pressure is usually very low. As carbon buildup increases, it can clog the nozzle orifice used for injecting the ignition fuel, causing the dual-fuel injector to malfunction.

[0003] To prevent carbon deposits from clogging the nozzles used for injecting ignition fuel, existing fuel engines propose to calculate the amount of carbon deposits on the fuel injector in real time, and when the amount of carbon deposits exceeds a set value, to inject fuel at the maximum fuel injection pressure in a single injection, thereby clearing the carbon deposits at the nozzles through a larger fuel flow rate.

[0004] In practical applications, it was found that the fuel consumption was high, which reduced the engine's economic performance; and the noise was high, which reduced the engine's NVH performance. Summary of the Invention

[0005] The purpose of this invention is to provide a dual-fuel injection system, control method, control device, and vehicle that can ensure the normal operation of the dual-fuel injection system while removing carbon deposits.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A dual-fuel injection system control method, wherein the fuel injected by the dual-fuel injection system includes a first fuel, which is a carbon fuel that serves as an ignition source. The dual-fuel injection system has a carbon deposit removal mode and a normal operating mode. The dual-fuel injection system control method includes the following steps:

[0008] During engine operation, the dual-fuel injection system is controlled to adjust the injection pressure of the first fuel according to the engine speed and torque;

[0009] When it is determined that the dual-fuel injection system needs carbon deposit removal, the dual-fuel injection system is switched from the normal operating mode to the carbon deposit removal mode;

[0010] When the engine speed and torque are the same, the injection pressure of the first fuel in the dual-fuel injection system is P1 when the system is operating in the carbon removal mode, and the injection pressure of the first fuel is P2 when the system is operating in the normal operating mode, where P1 > P2.

[0011] As one possible implementation of the above-mentioned dual-fuel injection system control method, the dual-fuel injection system control method further includes the following steps:

[0012] The cumulative duration of engine operation under high load conditions is calculated. When the cumulative duration of engine operation under high load conditions reaches a preset duration, it is determined that the dual-fuel injection system needs to undergo carbon deposit removal.

[0013] As one possible implementation of the above-mentioned dual-fuel injection system control method, when the dual-fuel injection system operates in the carbon removal mode for a preset removal time, the dual-fuel injection system is switched to the normal operating mode.

[0014] As one possible implementation of the above-mentioned dual-fuel injection system control method, the injection pressure P1 of the first fuel when the dual-fuel injection system is operating in the carbon deposit removal mode is obtained by the following steps:

[0015] Based on the first correspondence between the engine speed, engine torque and first fuel injection pressure P1 when the engine operates under high load conditions for a preset clearing time, the first fuel injection pressure P1 is determined by querying the actual engine speed and actual engine torque.

[0016] The injection pressure P2 of the first fuel when the dual-fuel injection system is operating in the normal working mode is obtained by the following steps:

[0017] Based on the second correspondence between engine speed, engine torque and first fuel injection pressure P2, the first fuel injection pressure P2 is determined by querying the actual engine speed and actual engine torque.

[0018] As one possible implementation of the above-mentioned dual-fuel injection system control method, the fuel injected by the dual-fuel injection system further includes a second fuel;

[0019] When the dual-fuel injection system is in the carbon removal mode, the displacement of the second fuel pump used to supply the second fuel in the dual-fuel injection system is adjusted according to the injection pressure of the first fuel, so as to adjust the injection pressure of the second fuel and make the pressure difference between the injection pressure of the first fuel and the injection pressure of the second fuel within a preset pressure difference range.

[0020] When the dual-fuel injection system is in the normal operating mode, it controls the pressure regulating unit in the second fuel supply device to operate according to the injection pressure of the first fuel, so as to adjust the injection pressure of the second fuel and make the pressure difference between the injection pressure of the first fuel and the injection pressure of the second fuel within a preset pressure difference range.

[0021] To achieve the above objectives, the present invention also provides a dual-fuel injection system, employing the dual-fuel injection system control method described in any of the above embodiments, wherein the dual-fuel injection system comprises:

[0022] A fuel injector having a first fuel injection channel for injecting a first fuel into a combustion chamber;

[0023] The first fuel supply device includes a first fuel pump and a first fuel storage unit. The inlet of the first fuel pump is connected to the first fuel storage unit, and the outlet of the first fuel pump is connected to the inlet of the first fuel injection channel. The first fuel pump is a variable pump.

[0024] As one possible implementation of the above-mentioned dual-fuel injection system, the first fuel supply device further includes a first fuel pressure detection unit for detecting the outlet pressure of the first fuel pump, and the fuel injector has a second fuel injection channel for injecting a second fuel into the combustion chamber.

[0025] The dual-fuel injection system also includes:

[0026] The second fuel supply device includes a second fuel pump, a second fuel storage unit, and a pressure regulating unit. The inlet of the second fuel pump is connected to the second fuel storage unit, and the outlet of the second fuel pump is connected to the inlet of the second fuel injection channel through the pressure regulating unit. The second fuel pump is a variable pump. The pressure regulating unit is used to adjust the pressure of the second fuel delivered to the second fuel injection channel according to the detection result of the first fuel pressure detection unit.

[0027] As one possible implementation of the above-mentioned dual-fuel injection system, the first fuel pump is connected to the inlet of the first fuel injection channel via the first fuel rail, and the pressure regulating unit is connected to the inlet of the second fuel injection channel via the second fuel rail;

[0028] The first fuel supply device further includes:

[0029] The first pressure relief valve is connected to the first fuel storage unit through the inlet of the first fuel injection channel;

[0030] The second pressure relief valve has its inlet connected to the inlet of the first pressure relief valve via a control switch valve, and its outlet connected to the outlet of the first pressure relief valve. The opening pressure of the second pressure relief valve is greater than that of the first pressure relief valve.

[0031] To achieve the above objectives, the present invention also provides a dual-fuel injection system control device for controlling the dual-fuel injection system described in any of the above embodiments to execute the dual-fuel injection system control method described in any of the above embodiments. The dual-fuel injection system control device includes:

[0032] The determination module is used to determine whether the dual-fuel injection system needs carbon deposit removal;

[0033] The first control module is used to control the dual-fuel injection system to perform the carbon deposit removal mode when the dual-fuel injection system needs to perform carbon deposit removal.

[0034] The second control module is used to control the dual-fuel injection system to perform the normal operating mode when carbon deposit removal is not required.

[0035] To achieve the above objectives, the present invention also provides a vehicle including the aforementioned dual-fuel injection system control device.

[0036] The beneficial effects of the present invention are as follows: The dual-fuel injection system, control method, control device and vehicle provided by the present invention, during engine operation, control the dual-fuel injection system to adjust the injection pressure of the first fuel according to the engine speed and torque, ensuring that the injection quantity of the first fuel meets the basic requirements of engine operation, and by limiting P1 to P2, the carbon deposits at the injection hole can be flushed away during the injection of the first fuel, avoiding the injection hole from being blocked, thereby enabling the first fuel injection channel to inject the first fuel normally into the combustion chamber.

[0037] This dual-fuel injection system control method can avoid the waste of the first fuel and improve the economy of engine operation; at the same time, it can minimize the impact of the first fuel injection on engine performance while ensuring that carbon deposits at the injection holes are washed away. Attached Figure Description

[0038] Figure 1 This is a simplified schematic diagram of the dual-fuel injection system provided in an embodiment of the present invention;

[0039] Figure 2 This is a flowchart of the dual-fuel injection system control method provided in an embodiment of the present invention.

[0040] In the picture:

[0041] 1. First fuel supply device; 11. First fuel storage unit; 12. First fuel pump; 13. First fuel filter; 14. First fuel rail; 15. First fuel pressure detection unit; 16. Control switch valve; 17. First pressure limiting valve; 18. Second pressure limiting valve;

[0042] 2. Second fuel supply device; 21. Second fuel storage unit; 22. Second fuel pump; 23. Second fuel filter; 24. Second fuel rail; 25. Second fuel pressure detection unit; 26. Pressure regulating unit;

[0043] 3. Fuel injector;

[0044] 4. Intake passage; 5. Exhaust passage; 6. Phase sensor; 7. Accelerator pedal; 8. Dual fuel injection system control device. Detailed Implementation

[0045] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0046] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0048] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, 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. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0049] like Figure 1 As shown, an embodiment of the present invention provides a dual-fuel injection system, including a fuel injector 3 and a first fuel supply device 1. The fuel injector 3 has a first fuel injection channel for injecting a first fuel into the combustion chamber of an engine. The first fuel supply device 1 includes a first fuel pump 12 and a first fuel storage unit 11. The inlet of the first fuel pump 12 is connected to the first fuel storage unit 11, and the outlet of the first fuel pump 12 is connected to the inlet of the first fuel injection channel. The first fuel pump 12 is a variable displacement pump. The first fuel is a carbonaceous fuel that serves as an ignition source. Exemplarily, the first fuel is fuel oil, such as diesel or gasoline. In other embodiments, the first fuel may also be dimethyl ether.

[0050] The combustion chamber is selectively connected to or disconnected from the intake passage 4 via the intake valve, and selectively connected to or disconnected from the exhaust passage 5 via the exhaust valve. A phase sensor 6 is installed on the engine. The phase sensor 6 is used to detect the engine's valve timing. The valve timing is the crankshaft angle corresponding to the opening and closing times of the engine's intake and exhaust valves according to the engine's working cycle. When the valve timing angle is determined to be inaccurate based on the detection signal from the phase sensor 6, the instrument lights on the vehicle are illuminated to indicate an engine malfunction.

[0051] The accelerator pedal 7 on the vehicle is used to control the opening of the engine throttle valve, thereby controlling the engine's power output.

[0052] The embodiments of the present invention also provide a dual-fuel injection system control method for the above-mentioned dual-fuel injection system. The dual-fuel injection system has a carbon deposit removal mode and a normal operating mode. When the engine speed and torque are the same, the injection pressure of the first fuel is P1 when the dual-fuel injection system is operating in the carbon deposit removal mode, and the injection pressure of the first fuel is P2 when the dual-fuel injection system is operating in the normal operating mode, where P1 > P2.

[0053] The dual-fuel injection system control method includes the following steps:

[0054] During engine operation, the dual-fuel injection system adjusts the injection pressure of the first fuel according to the engine speed and torque.

[0055] When it is determined that the dual-fuel injection system needs carbon deposit removal, the dual-fuel injection system is switched from the normal operating mode to the carbon deposit removal mode.

[0056] Specifically, the injection pressure of the first fuel is adjusted by regulating the displacement of the first fuel pump 12. When the dual-fuel injection system is operating in normal mode, the injection pressure P2 of the first fuel corresponds one-to-one with the displacement of the first fuel pump 12.

[0057] This dual-fuel injection system control method controls the dual-fuel injection system to adjust the injection pressure of the first fuel according to the engine speed and torque during engine operation, ensuring that the injection quantity of the first fuel meets the basic requirements of engine operation. By limiting P1 to P2, the carbon deposits at the injection orifice can be flushed away during the injection of the first fuel, preventing the injection orifice from being blocked, thereby enabling the first fuel injection channel to inject the first fuel normally into the combustion chamber.

[0058] This dual-fuel injection system control method can avoid the waste of the first fuel and improve the economy of engine operation; at the same time, it can minimize the impact of the first fuel injection on engine performance while ensuring that carbon deposits at the injection holes are washed away.

[0059] In some embodiments, the dual-fuel injection system control method further includes the following steps:

[0060] If the cumulative duration of engine operation under high load conditions is greater than or equal to a preset duration, it is determined that the dual-fuel injection system needs carbon deposit removal.

[0061] When the engine is under medium load, low load, or idling conditions, the temperature inside the combustion chamber is relatively low, making it less likely for carbon deposits to form. Therefore, the need for carbon deposit removal in the dual-fuel injection system is determined by whether the cumulative duration of engine operation under high load conditions is greater than or equal to a preset time.

[0062] The cumulative duration of engine operation under high load conditions refers to the total time the engine operates under high load conditions from the completion of one carbon deposit removal mode to the start of the next carbon deposit removal mode in the dual-fuel injection system. This can be either a single instance of the engine operating under high load conditions reaching the preset duration, or a single instance of the engine operating under high load conditions not reaching the preset duration, but the sum of the durations of multiple instances of the engine operating under high load conditions reaching the preset duration.

[0063] The carbon buildup that forms when the engine operates under high load conditions is determined through repeated tests, and the preset time is not specified here.

[0064] It should be noted that the high-load operating condition of the engine is determined based on the engine speed and torque. Specifically, the engine is in a high-load operating condition if the ratio of the current torque to the maximum torque at the current speed is not less than a preset ratio. For example, the preset ratio is 90%, and the maximum torque at the current speed is the torque corresponding to the current engine speed, retrieved based on the engine's speed-torque external characteristic curve.

[0065] In some embodiments, the injection pressure P1 of the first fuel when the dual-fuel injection system operates in carbon deposit removal mode is obtained by the following steps:

[0066] Based on the preset clearing time when the engine operates under high load conditions, the first correspondence between the engine speed, engine torque, and first fuel injection pressure P1 is determined by querying the actual engine speed and actual engine torque.

[0067] It should be noted that the first correspondence mentioned above can be a map or a data table determined through repeated experiments, etc., and will not be specifically limited here.

[0068] The injection pressure P2 of the first fuel in the dual-fuel injection system when operating in normal mode is obtained using the following steps:

[0069] Based on the second correspondence between engine speed, engine torque and first fuel injection pressure P2, the first fuel injection pressure P2 is determined by querying the actual engine speed and actual engine torque.

[0070] It should be noted that the second correspondence mentioned above can be a map or a data table determined through repeated experiments, etc., and will not be specifically limited here.

[0071] The second fuel injected by this dual-fuel injection system is different from the first fuel. The second fuel can be natural gas, methanol, etc. In this case, the first fuel is used to ignite the second fuel.

[0072] The first fuel supply device 1 also includes a first fuel pressure detection unit 15 for detecting the outlet pressure of the first fuel pump 12, and the fuel injector 3 has a second fuel injection channel for injecting a second fuel into the combustion chamber.

[0073] The dual-fuel injection system also includes a second fuel supply device 2, which includes a second fuel pump 22, a second fuel storage unit 21, and a pressure regulating unit 26. The inlet of the second fuel pump 22 is connected to the second fuel storage unit 21, and the outlet of the second fuel pump 22 is connected to the inlet of the second fuel injection channel through the pressure regulating unit 26. The second fuel pump 22 is a variable pump, and the pressure regulating unit 26 is used to adjust the pressure of the second fuel delivered to the second fuel injection channel according to the detection result of the first fuel pressure detection unit 15.

[0074] For example, the first fuel pressure detection unit 15 is a pressure sensor, and the pressure regulating unit 26 is an electromagnetic pressure reducing valve, which facilitates adjusting the pressure of the second fuel sent to the second fuel injection channel according to the detection results of the first fuel pressure detection unit 15.

[0075] Taking diesel as the first fuel and natural gas as the second fuel as an example, the first fuel storage unit 11 is a fuel tank, the second fuel storage unit 21 is an LNG cylinder, the first fuel pump 12 is a high-pressure oil pump, and the second fuel pump 22 is an LNG booster pump.

[0076] When the dual-fuel injection system is in normal operating mode, the pressure regulating unit 26 in the second fuel supply device 2 is controlled to operate according to the injection pressure of the first fuel, so as to adjust the injection pressure of the second fuel and make the pressure difference between the injection pressure of the first fuel and the injection pressure of the second fuel within a preset pressure difference range.

[0077] The pressure regulating unit 26 adjusts the pressure of the second fuel delivered to the second fuel injection channel according to the detection result of the first fuel pressure detection unit 15, so that the injection pressure of the second fuel follows the change of the injection pressure of the first fuel, and maintains a stable pressure difference between the injection pressure of the second fuel and the injection pressure of the first fuel, thereby ensuring the combustion stability in the combustion chamber.

[0078] When the dual-fuel injection system is in carbon deposit removal mode, because P1 is greater than P2 when the engine speed and torque are the same, the pressure regulating unit 26 may not be able to meet the injection pressure requirements of the second fuel even when it is at its maximum opening. That is, it cannot keep the injection pressure of the first fuel and the injection pressure of the second fuel within the preset pressure difference range. Replacing the pressure regulating unit 26 would increase costs and reduce the control accuracy of the second fuel injection pressure. Therefore, when the dual-fuel injection system is in carbon deposit removal mode, the displacement of the second fuel pump 22 used to supply the second fuel in the dual-fuel injection system is adjusted according to the injection pressure of the first fuel to regulate the injection pressure of the second fuel, so that the pressure difference between the injection pressure of the first fuel and the injection pressure of the second fuel is within the preset pressure difference range.

[0079] In some embodiments, the first fuel pump 12 is connected to the inlet of the first fuel rail 14 and the first fuel injection channel, and the pressure regulating unit 26 is connected to the inlet of the second fuel rail 24 and the second fuel injection channel.

[0080] During the operation of the dual-fuel injection system, the first fuel rail 14 prevents the gas pressure in the combustion chamber from affecting the outlet pressure of the first fuel pump 12, and the second fuel rail 24 prevents the gas pressure in the combustion chamber from affecting the outlet pressure of the second fuel pump 22.

[0081] In some embodiments, the first fuel supply device 1 further includes a first pressure limiting valve 17 and a second pressure limiting valve 18. The inlet of the first fuel injection channel is connected to the first fuel storage unit 11 through the first pressure limiting valve 17. The inlet of the second pressure limiting valve 18 is connected to the inlet of the first pressure limiting valve 17 through a control switch valve 16. The outlet of the second pressure limiting valve 18 is connected to the outlet of the first pressure limiting valve 17. The opening pressure of the second pressure limiting valve 18 is greater than the opening pressure of the first pressure limiting valve 17.

[0082] When the dual-fuel injection system is in normal operating mode, the first pressure relief valve 17 is activated to prevent excessive outlet pressure in the first fuel injection channel, thereby improving the accuracy of the first fuel injection pressure and correspondingly improving the accuracy of the second fuel injection pressure.

[0083] When the dual-fuel injection system is in carbon deposit removal mode, P1 is greater than P2 because the engine speed and torque are the same. Therefore, the control switch valve 16 is closed, so the first pressure limiting valve 17 does not work. At this time, the second pressure limiting valve 18 works to avoid excessive outlet pressure of the first fuel injection channel.

[0084] For example, the control switch valve 16 is an electromagnetic switch valve.

[0085] In some embodiments, when the dual-fuel injection system operates in carbon removal mode for a preset removal time, the dual-fuel injection system is switched to normal operating mode.

[0086] When the cumulative time the engine operates under high load conditions is greater than or equal to the preset time, the dual-fuel injection system will switch from the normal operating mode to the carbon deposit removal mode. Therefore, the preset removal time is based on the premise that the time the engine operates under high load conditions is equal to the preset time. The preset removal time is the time it takes to remove carbon deposits near the injection holes, which is determined through repeated tests. This is a known value and will not be specifically limited here.

[0087] When the dual-fuel injection system operates in carbon removal mode for the preset removal time, it indicates that the carbon removal is complete. The accumulated time of the engine operating under high load conditions is then reset to zero, and the accumulated time of the engine operating under high load conditions is re-accumulated.

[0088] In some embodiments, the dual-fuel injection system further includes a second fuel pressure detection unit 25, which is used to detect the outlet pressure of the second fuel pump 22. Exemplarily, the second fuel pressure detection unit 25 is a pressure sensor.

[0089] In some embodiments, a first fuel filter 13 is provided between the first fuel storage unit 11 and the first fuel pump 12, and a second fuel filter 23 is provided between the second fuel pump 22 and the pressure regulating unit 26.

[0090] When the first fuel is fuel oil, the first fuel filter 13 is a fuel oil filter; when the second fuel is natural gas, the second fuel filter 23 is a natural gas filter.

[0091] Figure 2 A flowchart of a dual-fuel injection system control method provided in a preferred embodiment is shown below. Figure 2 As shown, the dual-fuel injection system control method includes the following steps:

[0092] S10, The cumulative duration T1 of the engine operating under high load conditions during normal operation mode;

[0093] S20. Determine whether T1 is greater than or equal to the preset duration T0. If yes, execute S30; otherwise, return to S10.

[0094] S30, Control the dual-fuel injection system to switch to carbon deposit removal mode;

[0095] S40. Determine whether the working time T2 of the dual fuel injection system in carbon deposit removal mode has reached the preset removal time T3. If yes, execute S50; otherwise, return to S40.

[0096] S50 controls the dual-fuel injection system to switch to normal operating mode and resets the accumulated time of engine operation under high load conditions to zero.

[0097] An embodiment of the present invention also provides a dual-fuel injection system control device for controlling the dual-fuel injection system to perform the dual-fuel injection system control method. The pressure regulating unit 26, the first fuel pump 12, the second fuel pump 22, the first fuel pressure detection unit 15, the second fuel pressure detection unit 25, and the control switch valve 16 are all electrically connected to the dual-fuel injection system control device 8.

[0098] The dual-fuel injection system control device 8 includes a determining module, a first control module, and a second control module. The determining module is used to determine whether the dual-fuel injection system needs carbon deposit removal. The first control module is used to control the dual-fuel injection system to execute the carbon deposit removal mode when carbon deposit removal is required. The second control module is used to control the dual-fuel injection system to execute the normal operating mode when carbon deposit removal is not required.

[0099] When the dual-fuel injection system is operating in carbon removal mode, the system controls the injection pressure of the first fuel according to the engine speed and torque to ensure that the injection quantity of the first fuel meets the basic requirements of engine operation. By limiting P1 to P2, the first fuel injection can flush away the carbon deposits at the injection orifice, preventing the injection orifice from being blocked, thereby allowing the first fuel injection channel to inject the first fuel normally into the combustion chamber.

[0100] The dual-fuel injection system control device 8 can avoid the waste of the first fuel and improve the economy of engine operation; at the same time, it can minimize the impact of the first fuel injection on engine performance while ensuring that the carbon deposits at the injection holes are washed away.

[0101] An embodiment of the present invention also provides a vehicle including the dual-fuel injection system control device 8 described above. This vehicle has the same technical effects as the dual-fuel injection system control device 8 described above, and will not be repeated here.

[0102] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A control method for a dual-fuel injection system, characterized in that, The dual-fuel injection system injects a first fuel, which is a carbon-containing fuel that serves as an ignition source. The dual-fuel injection system has a carbon deposit removal mode and a normal operating mode. The control method for the dual-fuel injection system includes the following steps: During engine operation, the dual-fuel injection system is controlled to adjust the injection pressure of the first fuel according to the engine speed and torque; When it is determined that the dual-fuel injection system needs carbon deposit removal, the dual-fuel injection system is controlled to switch from the normal operating mode to the carbon deposit removal mode. When the engine speed and torque are the same, the injection pressure of the first fuel in the dual-fuel injection system is P1 when the system is operating in the carbon removal mode, and the injection pressure of the first fuel is P2 when the system is operating in the normal operating mode, where P1 > P2. The dual-fuel injection system also injects a second fuel. When the dual-fuel injection system is in the carbon removal mode, the displacement of the second fuel pump (22) used to supply the second fuel in the dual-fuel injection system is adjusted according to the injection pressure of the first fuel, so as to adjust the injection pressure of the second fuel and make the pressure difference between the injection pressure of the first fuel and the injection pressure of the second fuel within a preset pressure difference range. When the dual-fuel injection system is in the normal operating mode, the pressure regulating unit (26) in the second fuel supply device (2) is controlled to work according to the injection pressure of the first fuel to adjust the injection pressure of the second fuel so that the pressure difference between the injection pressure of the first fuel and the injection pressure of the second fuel is within a preset pressure difference range.

2. The dual-fuel injection system control method according to claim 1, characterized in that, The dual-fuel injection system control method further includes the following steps: The cumulative duration of engine operation under high load conditions is calculated. When the cumulative duration of engine operation under high load conditions reaches a preset duration, it is determined that the dual-fuel injection system needs to undergo carbon deposit removal.

3. The dual-fuel injection system control method according to claim 2, characterized in that, When the dual-fuel injection system operates in the carbon removal mode for a preset removal time, the dual-fuel injection system is switched to the normal operating mode.

4. The dual-fuel injection system control method according to claim 3, characterized in that, The injection pressure P1 of the first fuel when the dual-fuel injection system is operating in the carbon deposit removal mode is obtained using the following steps: Based on the first correspondence between the engine speed, engine torque and first fuel injection pressure P1 when the engine operates under high load conditions for a preset clearing time, the first fuel injection pressure P1 is determined by querying the actual engine speed and actual engine torque. The injection pressure P2 of the first fuel when the dual-fuel injection system is operating in the normal working mode is obtained by the following steps: Based on the second correspondence between engine speed, engine torque and first fuel injection pressure P2, the first fuel injection pressure P2 is determined by querying the actual engine speed and actual engine torque.

5. A dual-fuel injection system, characterized in that, The dual-fuel injection system control method according to any one of claims 1 to 4, wherein the dual-fuel injection system comprises: Fuel injector (3), the fuel injector (3) having a first fuel injection channel for injecting a first fuel into the combustion chamber; The first fuel supply device (1) includes a first fuel pump (12) and a first fuel storage unit (11). The inlet of the first fuel pump (12) is connected to the first fuel storage unit (11), and the outlet of the first fuel pump (12) is connected to the inlet of the first fuel injection channel. The first fuel pump (12) is a variable pump.

6. The dual-fuel injection system according to claim 5, characterized in that, The first fuel supply device (1) further includes a first fuel pressure detection unit (15) for detecting the outlet pressure of the first fuel pump (12), and the fuel injector (3) has a second fuel injection channel for injecting a second fuel into the combustion chamber; The dual-fuel injection system also includes: The second fuel supply device (2) includes a second fuel pump (22), a second fuel storage unit (21), and a pressure regulating unit (26). The inlet of the second fuel pump (22) is connected to the second fuel storage unit (21), and the outlet of the second fuel pump (22) is connected to the inlet of the second fuel injection channel through the pressure regulating unit (26). The second fuel pump (22) is a variable pump. The pressure regulating unit (26) is used to adjust the pressure of the second fuel delivered to the second fuel injection channel according to the detection result of the first fuel pressure detection unit (15).

7. The dual-fuel injection system according to claim 6, characterized in that, The first fuel pump (12) is connected to the inlet of the first fuel injection channel via the first fuel rail (14), and the pressure regulating unit (26) is connected to the inlet of the second fuel injection channel via the second fuel rail (24); The first fuel supply device (1) further includes: The first pressure relief valve (17) is connected to the first fuel storage unit (11) through the first pressure relief valve (17); The inlet of the second pressure relief valve (18) is connected to the inlet of the first pressure relief valve (17) through the control switch valve (16), and the outlet of the second pressure relief valve (18) is connected to the outlet of the first pressure relief valve (17). The opening pressure of the second pressure relief valve (18) is greater than the opening pressure of the first pressure relief valve (17).

8. A dual-fuel injection system control device, characterized in that, For controlling the dual-fuel injection system as described in any one of claims 5 to 7 to perform the dual-fuel injection system control method as described in any one of claims 1 to 4, the dual-fuel injection system control device (8) comprises: The determination module is used to determine whether the dual-fuel injection system needs carbon deposit removal; The first control module is used to control the dual-fuel injection system to perform the carbon deposit removal mode when the dual-fuel injection system needs to perform carbon deposit removal. The second control module is used to control the dual-fuel injection system to perform the normal operating mode when carbon deposit removal is not required.

9. A vehicle, characterized in that, Includes the dual-fuel injection system control device (8) as described in claim 8.

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