Ammonia and natural gas synergistic combustion engine high-pressure injection system and control method
By adopting a high-pressure injection system and control method for collaborative combustion of ammonia and natural gas in the engine, the problem of instability of ammonia combustion is solved, efficient ammonia combustion is achieved, and emissions and fuel costs are reduced.
Patent Information
- Application Number
- CN202510431579.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-08
- Publication Date
- 2025-06-06
AI Technical Summary
As engine fuel, ammonia has problems such as high ignition temperature and combustible lower limit concentration, difficulty in ignition, low flame propagation speed and poor combustion stability. It is especially prominent in marine large-bore two-stroke engines, resulting in unstable ammonia combustion, increased NOX emissions, and decreased power and thermal efficiency.
The high-pressure injection system and control method of the engine are adopted for the high-pressure injection system and control method through the high-pressure injection technology to achieve the coordinated combustion of ammonia and natural gas, reduce the diesel supply, improve the combustion efficiency of ammonia, and dynamically adjust the supply ratio of ammonia and natural gas through electronic controllers (ECUs) to maintain the high-power operation of the engine.
While maintaining a low diesel ignition ratio, the cost of ship fuel and fossil fuel usage are greatly reduced, and the engine's carbon dioxide and unburned methane emissions are significantly reduced.
Smart Images
Figure CN120100579A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an engine high-pressure injection system and to a control method of the system. Background Art
[0002] In order to effectively reduce greenhouse gas emissions and reduce the use of traditional fossil fuels, the use of low-carbon or zero-carbon fuels and improving engine thermal efficiency are currently important ways to choose engine fuels. Ammonia has become the most promising zero-carbon fuel due to its high octane number, good anti-knock performance, and the ability to improve the thermal efficiency of the engine through a high compression ratio to achieve efficient combustion and work. On the other hand, the carbon emissions of ammonia fuel produced by the engine using renewable energy is only 0.065g / MJ, thus greatly reducing carbon emissions. However, ammonia as an engine fuel also has defects such as high ignition temperature and lower flammable limit concentration, difficult ignition, low flame propagation speed and poor combustion stability. Especially for large-bore marine two-stroke engines, the problems of difficult ammonia ignition, poor stability of the combustion process, long flame propagation time and slow combustion reaction speed will be more prominent. Although ammonia can reduce CO by replacing diesel 2 Emissions, but NO X Emissions rise, while engine power and thermal efficiency decrease.
[0003] Replacing diesel with natural gas is also a way to reduce the use of traditional fossil fuels. The engine power and thermal efficiency remain almost unchanged, but CO 2 and NO X The emission effect is limited. Summary of the invention
[0004] The technical problem to be solved by the present invention is to provide a high-pressure injection system and control method for an ammonia and natural gas co-combustion engine, which can realize the co-combustion of ammonia and natural gas through high-pressure injection of ammonia and natural gas, reduce the diesel supply for pure diesel ignition of ammonia, achieve high-proportion ammonia substitution while maintaining high engine power, and thereby achieve carbon dioxide emission reduction.
[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: A high-pressure injection system for an ammonia and natural gas cooperative combustion engine comprises a piston installed inside an engine cylinder, wherein the space above the piston inside the engine cylinder is a combustion chamber, the piston is connected to a crankshaft located in the space below the piston via a crosshead, and further comprises a diesel supply system, a natural gas supply system, an ammonia supply system and an ECU, the combustion chamber is installed with a diesel injector, a dual-fuel injector and a pressure sensor; the crankshaft is connected to a crankshaft angle sensor; the diesel supply system is connected to the diesel injector via a third electronic control valve, the natural gas supply system is connected to the dual-fuel injector via a second electronic control valve, and the ammonia supply system is connected to the dual-fuel injector via a first electronic control valve; the ECU is respectively connected to the first electronic control valve, the second electronic control valve and the third electronic control valve, the crankshaft angle sensor and the pressure sensor.
[0006] The control method of the high-pressure injection system of the ammonia and natural gas cooperative combustion engine, the diesel supply system, the natural gas supply system and the ammonia supply system supply high-pressure fuel greater than or equal to 30MPa to the combustion chamber, and the high-pressure injection is controlled by the ECU.
[0007] Furthermore, the ECU collects crankshaft angle data through a crankshaft angle sensor, and controls the injection timing of the first electronic control valve, the second electronic control valve and the third electronic control valve; the ECU collects engine cylinder pressure data through a pressure sensor, and controls the injection duration of the first electronic control valve, the second electronic control valve and the third electronic control valve.
[0008] Furthermore, when the engine pressure value detected by the pressure sensor fluctuates and the fluctuation range is within ±15%, if the pressure value is lower than the set pressure value, ECU4 controls the first electronic control valve to reduce the ammonia supply ratio, and controls the second electronic control valve to increase the natural gas supply ratio to achieve pressure increase; if the pressure value is higher than the set pressure value, ECU4 controls the first electronic control valve to increase the ammonia supply ratio, and controls the second electronic control valve to reduce the natural gas supply ratio to achieve pressure reduction to maintain high-power operation of the engine; when the engine pressure value detected by the pressure sensor fluctuates and the fluctuation range exceeds ±15%, ECU4 controls the first electronic control valve to reduce the ammonia supply ratio, and controls the second electronic control valve to increase the natural gas supply ratio to ensure stable ignition of ammonia.
[0009] The positive effects of the present invention are: The present invention can replace diesel and natural gas with ammonia fuel in large proportion while maintaining an extremely low ignition diesel ratio, greatly reducing the fuel cost of ships and the amount of fossil fuels used. The present invention measures the in-cylinder pressure and dynamically adjusts ammonia and natural gas, thereby minimizing engine carbon dioxide emissions and unburned methane emissions while maintaining high engine power output.
[0010] The invention is particularly suitable for a large-bore high-pressure direct-injection two-stroke marine natural gas-diesel dual-fuel prototype engine. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 It is a schematic diagram of the structure and working principle of an embodiment of the system of the present invention.
[0012] Description of reference numerals: 1. Diesel supply system; 2. Natural gas supply system; 3. Ammonia supply system; 4. ECU; 5. First electronic control valve; 6. Second electronic control valve; 7. Third electronic control valve; 8. Exhaust valve; 9. Exhaust pipe; 10. Piston; 11. Combustion chamber; 12. Crosshead; 13. Crankshaft; 14. Crankshaft angle sensor; 15. Diesel injector; 16. Dual fuel injector; 17. Pressure sensor. DETAILED DESCRIPTION
[0013] The present invention is further described below with reference to the accompanying drawings and embodiments.
[0014] like Figure 1 The system embodiment of the present invention includes a piston 10 installed inside an engine cylinder. Inside the engine cylinder, the space above the piston 10 is a combustion chamber 11, and the piston 10 is connected to a crankshaft 13 located in the space below the piston 10 through a crosshead 12. An exhaust pipe 9 is installed at the upper end of the engine cylinder through an exhaust valve 8.
[0015] The system embodiment of the present invention further includes a diesel supply system 1, a natural gas supply system 2, an ammonia supply system 3 and an ECU 4. The combustion chamber 11 is also equipped with a diesel injector 15 and a dual-fuel injector 16. The diesel supply system 1 is connected to the diesel injector 15 through a third electronic control valve 7, the natural gas supply system 2 is connected to the dual-fuel injector 16 through a second electronic control valve 6, and the ammonia supply system 3 is connected to the dual-fuel injector 16 through a first electronic control valve 5.
[0016] The crankshaft 13 is connected to a crank angle sensor 14. The combustion chamber 11 is also equipped with a pressure sensor 17. The ECU 4 is connected to the first electronic control valve 5, the second electronic control valve 6, the third electronic control valve 7, the crank angle sensor 14 and the pressure sensor 17 respectively.
[0017] The ECU described in the present invention refers to an electronic control unit.
[0018] When the engine is operating normally, the crankshaft 13 drives the crosshead 12 and the piston 10 to reciprocate up and down. Near the top dead center, the ECU4 first controls the third electronic control valve 7 to inject the diesel in the diesel supply system 1 into the combustion chamber 11 through the diesel injector 15, and then the ECU4 controls the first electronic control valve 5 and the second electronic control valve 6 to inject the ammonia in the ammonia supply system 3 and the natural gas in the natural gas supply system 2 into the combustion chamber 11 through the dual fuel injector 16. The natural gas is ignited by the diesel, and the ammonia is ignited by the energy released by the combustion of the natural gas, so that the ammonia and natural gas are synergistically burned to do work, and the exhaust gas is discharged from the system through the exhaust valve 8 and the exhaust pipe 9.
[0019] The ECU 4 collects the rotation angle data of the crankshaft 13 through the crankshaft rotation angle sensor 14, and controls the injection timing of the first electronic control valve 5, the second electronic control valve 6 and the third electronic control valve 7. The ECU 4 collects the pressure data in the engine cylinder through the pressure sensor 17, and controls the injection duration of the first electronic control valve 5, the second electronic control valve 6 and the third electronic control valve 7.
[0020] In this embodiment, the diesel supply system 1, the natural gas supply system 2 and the ammonia supply system 3 supply high-pressure fuel of 30 MPa or more to the combustion chamber 11, and the high-pressure injection is controlled by the ECU 4.
[0021] When the engine pressure value detected by the pressure sensor 17 is stably equal to the set pressure value, the ECU 4 does not take any action.
[0022] When the engine pressure value detected by the pressure sensor 17 fluctuates and the fluctuation amplitude is within ±15%, if the pressure value is lower than the set pressure value, ECU4 controls the first electronic control valve 5 to reduce the ammonia supply ratio, and controls the second electronic control valve 6 to increase the natural gas supply ratio to achieve pressure increase; if the pressure value is higher than the set pressure value, ECU4 controls the first electronic control valve 5 to increase the ammonia supply ratio, and controls the second electronic control valve 6 to reduce the natural gas supply ratio to achieve pressure reduction, so as to maintain high-power operation of the engine.
[0023] When the engine pressure value detected by the pressure sensor 17 fluctuates and the fluctuation amplitude exceeds ±15%, the ECU 4 controls the first electronic control valve 5 to reduce the ammonia supply ratio, and controls the second electronic control valve 6 to increase the natural gas supply ratio to ensure stable ignition of ammonia.
[0024] The set pressure value is the maximum explosion pressure value of the engine factory bench test.
Claims
1. A high-pressure injection system for an ammonia and natural gas co-combustion engine, comprising a piston (10) installed inside an engine cylinder, wherein the space above the piston (10) inside the engine cylinder is a combustion chamber (11), and the piston (10) is connected to a crankshaft (13) located in the space below the piston (10) via a crosshead (12), and further comprising a diesel supply system (1), a natural gas supply system (2), an ammonia supply system (3) and an ECU (4), characterized in that: The combustion chamber (11) is equipped with a diesel injector (15), a dual-fuel injector (16) and a pressure sensor (17); the crankshaft (13) is connected to a crankshaft angle sensor (14); the diesel supply system (1) is connected to the diesel injector (15) via a third electronic control valve (7), the natural gas supply system (2) is connected to the dual-fuel injector (16) via a second electronic control valve (6), and the ammonia supply system (3) is connected to the dual-fuel injector (16) via a first electronic control valve (5); and the ECU (4) is respectively connected to the first electronic control valve (5), the second electronic control valve (6) and the third electronic control valve (7), the crankshaft angle sensor (14) and the pressure sensor (17).
2. The control method of the high-pressure injection system of the ammonia and natural gas cooperative combustion engine according to claim 1 is characterized in that: The diesel supply system (1), the natural gas supply system (2) and the ammonia supply system (3) supply high-pressure fuel of 30 MPa or more to the combustion chamber (11), and control the high-pressure injection through the ECU (4).
3. The control method of the high-pressure injection system of the ammonia and natural gas cooperative combustion engine according to claim 2 is characterized in that: The ECU (4) collects rotation angle data of the crankshaft (13) through a crankshaft rotation angle sensor (14), and controls the injection timing of the first electronic control valve (5), the second electronic control valve (6), and the third electronic control valve (7); the ECU (4) collects pressure data in the engine cylinder through a pressure sensor (17), and controls the injection duration of the first electronic control valve (5), the second electronic control valve (6), and the third electronic control valve (7).
4. The control method of the high-pressure injection system of the ammonia and natural gas cooperative combustion engine according to claim 2 or 3, characterized in that: When the engine pressure value detected by the pressure sensor (17) fluctuates and the fluctuation range is within ±15%, if the pressure value is lower than the set pressure value, the ECU4 controls the first electronic control valve (5) to reduce the ammonia supply ratio and controls the second electronic control valve (6) to increase the natural gas supply ratio to achieve pressure increase; if the pressure value is higher than the set pressure value, the ECU4 controls the first electronic control valve (5) to increase the ammonia supply ratio and controls the second electronic control valve (6) to reduce the natural gas supply ratio to achieve pressure reduction to maintain high power operation of the engine; when the engine pressure value detected by the pressure sensor (17) fluctuates and the fluctuation range exceeds ±15%, the ECU4 controls the first electronic control valve (5) to reduce the ammonia supply ratio and controls the second electronic control valve (6) to increase the natural gas supply ratio to ensure stable ignition of ammonia.