Ammonia-hydrogen internal combustion engine and control method

Abstract

The present application provides a kind of ammonia hydrogen internal combustion engine and control method, exhaust heat energy is recycled, while realizing safe and reliable fuel supply and reducing the abnormal combustion of hydrogen fuel to realize high power and high efficiency.It includes intake system, pre-storage hydrogen supply system, liquid oil hydrogen storage supply system, pressure storage ammonia (liquid ammonia) supply system and control system.Its advantages are that the exhaust heat of internal combustion engine can be used to provide heat for hydrogen oil hydrogen storage system to produce hydrogen fuel.The pressure storage ammonia (liquid ammonia) system has stable working pressure, so that ammonia fuel can be mixed with hydrogen fuel in the form of liquid ammonia, and the large latent heat of vaporization can overcome the abnormal combustion of hydrogen internal combustion engine, and the large volume energy density can also increase the power performance of internal combustion engine.The internal combustion engine and control method can realize safe and reliable fuel supply and reduce the abnormal combustion of hydrogen fuel, and have good development prospect.

Description

Technical Field

[0001] A method for controlling an ammonia-hydrogen internal combustion engine specifically relates to a method for achieving ammonia-hydrogen fuel mixing and combustion in an ammonia-hydrogen internal combustion engine using a hydrogen oil storage system and a pressurized ammonia storage (liquid ammonia) system, belonging to the field of internal combustion engines. Background Technology

[0002] With socio-economic development, environmental safety issues and increasingly variable global weather patterns have seriously impacted human health. Clean energy can effectively reduce air pollution, maintain clean air, and thus improve people's quality of life. However, with the gradual increase in my country's car ownership, the country's resource distribution—poor in oil, scarce in gas, and abundant in coal—is leading to a growing dependence on imported oil, posing a threat to its energy security system.

[0003] Hydrogen fuel, as a highly efficient and clean energy source, possesses characteristics such as high calorific value, rapid flame propagation speed, and low auto-ignition temperature. However, it is also prone to abnormal combustion phenomena such as pre-ignition, backfire, and detonation. Furthermore, its storage and transportation safety issues are a significant factor limiting the application and promotion of hydrogen engines. Ammonia, as a high-hydrogen energy carrier, boasts advantages such as low production and storage costs, long storage and transportation time, easy liquefaction, and high volumetric energy density, making it a promising zero-carbon fuel. However, its low calorific value, slow laminar flame velocity, high ignition energy, and narrow ignition threshold limit its use in engines. Additionally, the waste heat from engine exhaust carries away some heat, reducing the efficiency of the internal combustion engine.

[0004] Therefore, this application designs a hydrogen / liquid ammonia dual-fuel internal combustion engine and its control method. This system adds a pressurized ammonia (liquid ammonia) supply system to provide liquid ammonia to the internal combustion engine, and a hydrogen oil storage system. By utilizing the waste heat from the internal combustion engine exhaust to heat the dehydrogenation reaction device in this system, the hydrogen oil, under the catalytic action of a catalyst at this temperature, produces hydrogen gas, providing hydrogen fuel for the internal combustion engine. Utilizing the high latent heat of vaporization and volumetric energy density of liquid ammonia, the abnormal combustion of hydrogen fuel in the internal combustion engine is controlled by adjusting the fuel ratio under different operating conditions, fully utilizing the waste heat from the internal combustion engine exhaust, and improving the engine's operating efficiency. Summary of the Invention

[0005] To eliminate abnormal combustion in hydrogen internal combustion engines and recover exhaust energy, thereby improving engine economy, this application proposes a hydrogen / liquid ammonia dual-fuel internal combustion engine and its control method. By adding a pressurized ammonia (liquid ammonia) supply system and a hydrogen-oil hydrogen storage system, not only can liquid ammonia fuel be provided to the internal combustion engine, but waste heat from the exhaust gas can also be recovered, improving the engine's operating efficiency, preventing abnormal combustion under different operating conditions, and achieving high power output.

[0006] The present invention solves the above-mentioned technical problem through the following technical solution:

[0007] A hydrogen / liquid ammonia dual-fuel internal combustion engine includes: P1 engine intake system, P2 pre-storage hydrogen supply system, P3 accumulator ammonia (liquid ammonia) supply system, P4 hydrogen supply system, P5 hydrogen-oil storage system, and P6 ECU control system.

[0008] P1 Engine Intake System: The engine intake system includes an air filter (8), a throttle valve (9), an air flow sensor (10), and an intake pressure sensor (11).

[0009] The P2 pre-storage hydrogen supply system includes a hydrogen cylinder (1), a first hydrogen pressure reducing valve (2), a first hydrogen flow sensor (3), and a first hydrogen control switch (16); the P3 accumulator ammonia (liquid ammonia) supply system includes an accumulator ammonia tank (liquid ammonia) (4), an ammonia pressure reducing valve (5), an ammonia flow sensor (6), and an ammonia injector (7); the P4 hydrogen supply system includes a hydrogen cylinder (18), a second hydrogen pressure reducing valve (15), a second hydrogen flow sensor (14), a flame arrester (13), and a hydrogen injector (12); the P5 hydrogen oil storage system includes a hydrogen oil storage tank (19), an oil pump (20), a dehydrogenation system reaction device (21), a temperature sensor (22), a third hydrogen flow sensor (24), and a second hydrogen control switch (17); the P6 ECU control system includes an ECU (29), an oxygen sensor (23), a knock sensor (25), a spark plug (26), a speed sensor (27), and a crankshaft position sensor (28).

[0010] The P6 ECU control system interacts with the engine intake system (P1) via signals: the ECU (29) is connected to the throttle body (9) and the air flow sensor (10) via wires. Throttle body opening is controlled by sending a throttle control signal to the throttle body (9). The intake pressure sensor (11) detects the intake pressure in the intake manifold, and the air flow sensor (10) feeds back the detected signal to the ECU (18) to adjust the engine intake air volume.

[0011] The ECU control system (P6) interacts with the pre-stored hydrogen supply system (P2): the ECU (29) is connected to the first hydrogen pressure reducing valve (2) via a wire to adjust the hydrogen injection pressure. It is also connected to the first hydrogen flow sensor (3) and the first hydrogen control switch (16) to control the hydrogen flow and hydrogen switch.

[0012] The ECU control system (P6) interacts with the accumulator ammonia (liquid ammonia) supply system (P3): the ECU (29) is connected to the ammonia pressure reducing valve (5) via a wire, and adjusts the ammonia injection pressure through throttle control signals and knock signals. At the same time, the wire is also connected to the ammonia flow sensor (6) and the ammonia injector (7). The ECU (29) controls the injection pulse width and injection timing through the ammonia injector (7), and makes corrections through the feedback signal from the ammonia flow sensor (6).

[0013] The ECU control system (P6) interacts with the hydrogen supply system (P4) via signals: the ECU (29) is connected to the second hydrogen pressure reducing valve (15) via a wire, and adjusts the hydrogen injection pressure through throttle control signals and knock signals. At the same time, the wire is also connected to the second hydrogen flow sensor (14) and the hydrogen injector (12). The ECU (29) controls the injection pulse width and injection timing through the hydrogen injector (12), and makes corrections based on the feedback signal from the second hydrogen flow sensor (14).

[0014] The ECU control system (P6) interacts with the hydrogen oil storage system (P5) via signal exchange: the ECU (29) is connected to the oil pump (20), the third hydrogen flow sensor (24), the temperature sensor (22), and the second hydrogen control switch (17) via wires. The ECU (29) controls the hydrogen oil pump (20) to pump hydrogen oil from the hydrogen oil storage tank (19) to the dehydrogenation system reactor (21), while maintaining the temperature within the reaction temperature range of the dehydrogenation system reactor (21) through detection and feedback from the temperature sensor (22). The second hydrogen control switch (17) controls the supply and shutdown of hydrogen generated by the dehydrogenation system reactor (21), and corrects the feedback signal through the third hydrogen flow sensor (24).

[0015] The ECU control system (P6) involves signal interaction: the ECU (29) is connected to the speed sensor (27) and crankshaft position sensor (28) via wires to determine the engine speed and the position of the compression top pivot, providing a reference for fuel injection timing and injection pulse width. The ECU (29) receives signals from the oxygen sensor (23) and controls the engine's excess air coefficient. The ECU (29) is connected to the knock sensor (25) and spark plug (26) via wires to determine whether knocking occurs in the cylinder and adjust the ignition timing to prevent knocking.

[0016] A control method for an ammonia-hydrogen internal combustion engine, the method comprising a fuel supply strategy and a combustion control strategy:

[0017] (1) Fuel supply strategy

[0018] The ECU (29) receives signals from the speed sensor (27), crankshaft position sensor (28), and intake pressure sensor (11). By controlling the opening of the throttle valve (9), the intake pressure is set to 30 kPa. This is the starting condition. In order for the engine to start normally, a pure hydrogen mode combustion strategy is adopted through the P2 pre-stored hydrogen supply system. The ECU (29) keeps the first hydrogen control switch (16) in the P2 pre-stored hydrogen supply system open through the electronic control system, while the second hydrogen control switch (17) in the P5 hydrogen oil storage system is closed. The ECU (29) controls the hydrogen supply through the first hydrogen pressure reducing valve (2), the second hydrogen pressure reducing valve (15), and the hydrogen injector (12), and controls the air supply through the throttle valve (9). It also makes feedback adjustments based on the first hydrogen flow sensor (3), the second hydrogen flow sensor (14), the air flow sensor (10), and the intake pressure sensor (11) to maintain an excess air coefficient λ = 1.2. At the same time, the ECU (29) closes the ammonia pressure reducing valve (5) to ensure that no ammonia fuel is supplied to the engine during startup.

[0019] The ECU (29) receives signals from the speed sensor (27), crankshaft position sensor (28) and intake pressure sensor (11), and controls the throttle valve (9) opening to make the throttle valve fully open, maintaining an excess air coefficient λ = 1.5 and ammonia gas accounting for 60% of the total fuel volume fraction VNH3, so that the engine works under low load conditions. In order to ensure power output and avoid abnormal combustion, a liquid ammonia / hydrogen dual fuel injection strategy is adopted. The ECU (29) uses the electronic control system to open the first hydrogen control switch (16) in the P2 pre-hydrogen supply system and close the second hydrogen control switch (17) in the P5 hydrogen oil storage system. The ECU (29) controls the hydrogen supply through the first hydrogen pressure reducing valve (2), the second hydrogen pressure reducing valve (15), and the hydrogen injector (12), and controls the air supply through the throttle valve (9). It also makes feedback adjustments based on the first hydrogen flow sensor (3), the second hydrogen flow sensor (14), the air flow sensor (10), and the intake pressure sensor (11). At the same time, the ECU (29) uses the electronic control system to supply liquid ammonia fuel to the engine through the P3 accumulator ammonia (liquid ammonia) supply system via the ammonia pressure reducing valve (5) and the ammonia injector (7), and makes signal feedback corrections through the ammonia flow sensor (6).

[0020] The ECU (29) receives signals from the speed sensor (27), crankshaft position sensor (28), and intake pressure sensor (11). By controlling the opening of the throttle valve (9), the throttle valve is fully opened, maintaining the excess air coefficient λ at around 1 to 1.2. At the same time, the volume fraction of ammonia in the total fuel, VNH3, is 70% to 90%, so that the engine works under medium to high load conditions. In order to ensure power output and avoid abnormal combustion, a liquid ammonia / hydrogen dual-fuel injection strategy is adopted. The ECU (29) keeps the first hydrogen control switch (16) in the P2 pre-stored hydrogen supply system closed through the electronic control system, while the second hydrogen control switch (17) in the P5 hydrogen oil storage system is open. Through coordinated control with the ECU (29), the hydrogen generated by the dehydrogenation system reaction device (21) enters the combustion chamber through the third hydrogen flow sensor (24), the second hydrogen pressure reducing valve (15), the second hydrogen flow sensor (14), and the hydrogen injector (12). At the same time, the ECU (29) uses the electronic control system to enable the P3 accumulator ammonia (liquid ammonia) supply system to supply liquid ammonia fuel to the engine through the ammonia pressure reducing valve (5) and ammonia injector (7), and performs signal feedback correction through the ammonia flow sensor (6).

[0021] The excess air coefficient λ of the combustion mixture is the ratio of the actual air requirement to the theoretical air requirement during fuel combustion.

[0022] ammonia fuel volume fraction

[0023] and These represent the volumetric flow rates of NH3 (L / min) and H2 (L / min), respectively.

[0024] (2) Combustion control strategy

[0025] The ECU (29) determines whether there is knock or other abnormal combustion in the engine cylinder by detecting the signal transmitted by the knock sensor (25). If the knock sensor (25) determines that there is no knock or other abnormal combustion in the cylinder, the ECU (29) controls the ignition timing of the spark plug (26) according to the torque demand to keep the ignition timing at the optimal ignition angle.

[0026] If the knock sensor (25) determines that knocking or other abnormal combustion has occurred in the cylinder, the ECU (29) will delay the ignition timing of the spark plug (26) until the ignition timing of the spark plug (26) is delayed to the top dead center of the compression stroke to eliminate the knocking phenomenon.

[0027] If delaying the ignition timing to top dead center of the compression cycle still fails to eliminate knocking, the ECU (29) controls the injection quantity of liquid ammonia fuel by controlling the ammonia pressure reducing valve (5) and ammonia injector (7) in the P3 accumulator ammonia supply system, gradually increasing the injection quantity to eliminate knocking. When the knock sensor does not detect a knocking signal, the ammonia injection quantity remains constant under this operating condition. Attached Figure Description

[0028] Figure 1 The structure and working principle of this invention

[0029] Figure 1 In the middle: Engine intake system (P1): air filter (8), throttle valve (9), air flow sensor (10) and intake pressure sensor (11); Pre-stored hydrogen supply system (P2): hydrogen cylinder (1), first hydrogen pressure reducing valve (2), first hydrogen flow sensor (3), first hydrogen control switch (16); accumulator ammonia (liquid ammonia) supply system (P3): accumulator ammonia tank (liquid ammonia) (4), ammonia pressure reducing valve (5), ammonia flow sensor (6), ammonia injector (7); Hydrogen supply system (P4): hydrogen tank (18), second Hydrogen pressure reducing valve (15), second hydrogen flow sensor (14), flame arrester (13), hydrogen injector (12); Hydrogen oil storage system (P5): hydrogen oil storage tank (19), oil pump (20), dehydrogenation system reaction device (21), temperature sensor (22), third hydrogen flow sensor (24), second hydrogen control switch (17); ECU control system (P6): ECU (29), oxygen sensor (23), knock sensor (25), spark plug (26), speed sensor (27), crankshaft position sensor (28). Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0031] The system includes: an air filter (8), a throttle valve (9), an air flow sensor (10), and an intake pressure sensor (11) connected in series on the engine intake system (P1); a hydrogen cylinder (1), a first hydrogen pressure reducing valve (2), a first hydrogen flow sensor (3), and a first hydrogen control switch (16) connected in series on the pre-storage hydrogen supply system (P2); a accumulator ammonia (liquid ammonia) supply system (P3) including: an accumulator ammonia tank (liquid ammonia) (4), an ammonia pressure reducing valve (5), an ammonia flow sensor (6), and an ammonia injector (7) connected in series on the accumulator ammonia supply system (P4); and a hydrogen supply system (P4) including: a hydrogen cylinder (1... 8) Second hydrogen pressure reducing valve (15), second hydrogen flow sensor (14), flame arrester (13), hydrogen injector (12); The hydrogen oil storage system (P5) is connected in series with: hydrogen oil storage tank (19), oil pump (20), dehydrogenation system reaction device (21), temperature sensor (22), third hydrogen flow sensor (24), second hydrogen control switch (17); In the ECU control system (P6), the ECU (29) interacts with the oxygen sensor (23), knock sensor (25), spark plug (26), speed sensor (27), and crankshaft position sensor (28).

[0032] The ECU control system (P6) interacts with the engine intake system (P1) via signals: the ECU (29) is connected to the throttle body (9) and the air flow sensor (10) via wires. Throttle body opening is controlled by sending a throttle control signal to the throttle body (9), and the intake pressure in the intake manifold is detected by the intake pressure sensor (11). The air flow sensor (10) feeds back the detected signal to the ECU (18) to adjust the engine intake air volume.

[0033] The ECU control system (P6) interacts with the pre-stored hydrogen supply system (P2): the ECU (29) is connected to the first hydrogen pressure reducing valve (2) via a wire to adjust the hydrogen injection pressure. It is also connected to the first hydrogen flow sensor (3) and the first hydrogen control switch (16) to control the hydrogen flow and the hydrogen control switch.

[0034] The ECU control system (P6) interacts with the accumulator ammonia (liquid ammonia) supply system (P3): the ECU (29) is connected to the ammonia pressure reducing valve (5) via a wire, and adjusts the ammonia injection pressure through throttle control signals and knock signals. At the same time, the wire is also connected to the ammonia flow sensor (6) and the ammonia injector (7). The ECU (29) controls the injection pulse width and injection timing through the ammonia injector (7), and makes corrections through the feedback signal from the ammonia flow sensor (6).

[0035] The ECU control system (P6) interacts with the hydrogen supply system (P4) via signals: the ECU (29) is connected to the second hydrogen pressure reducing valve (15) via a wire, and adjusts the hydrogen injection pressure through throttle control signals and knock signals. At the same time, the wire is also connected to the second hydrogen flow sensor (14) and the hydrogen injector (12). The ECU (29) controls the injection pulse width and injection timing through the hydrogen injector (12), and makes corrections based on the feedback signal from the second hydrogen flow sensor (14).

[0036] The ECU control system (P6) interacts with the hydrogen oil storage system (P5) via signal exchange: the ECU (29) is connected to the oil pump (20), the third hydrogen flow sensor (24), the temperature sensor (22), and the second hydrogen control switch (17) via wires. The ECU (29) controls the hydrogen oil pump (20) to pump hydrogen oil from the hydrogen oil storage tank (19) to the dehydrogenation system reactor (21), while maintaining the temperature within the reaction temperature range of the dehydrogenation system reactor (21) through detection and feedback from the temperature sensor (22). The second hydrogen control switch (17) controls the supply and shutdown of hydrogen generated by the dehydrogenation system reactor (21), and corrects the feedback signal through the third hydrogen flow sensor (24).

[0037] The ECU control system (P6) involves signal interaction, and its main characteristics are as follows: The ECU (29) is connected to the speed sensor (27) and crankshaft position sensor (28) via wires to determine the engine speed and the position of the compression top pivot, providing a reference for fuel injection timing and injection pulse width. The ECU (29) receives the signal transmitted by the oxygen sensor (23) and controls the excess air coefficient of the engine. The ECU (29) is connected to the knock sensor (25) and spark plug (26) via wires to determine whether knocking occurs in the cylinder and adjust the ignition timing to avoid knocking.

[0038] An ammonia-hydrogen internal combustion engine and its control method, the method comprising a fuel supply strategy and a combustion control strategy:

[0039] (1) Fuel supply strategy

[0040] The ECU (29) receives signals from the speed sensor (27), crankshaft position sensor (28), and intake pressure sensor (11). By controlling the opening of the throttle valve (9), the intake pressure is set to 30 kPa. This is the starting condition. In order for the engine to start normally, a pure hydrogen mode combustion strategy is adopted through the P2 pre-stored hydrogen supply system. The ECU (29) keeps the first hydrogen control switch (16) in the P2 pre-stored hydrogen supply system open through the electronic control system, while the second hydrogen control switch (17) in the P5 hydrogen oil storage system is closed. The ECU (29) controls the hydrogen supply through the first hydrogen pressure reducing valve (2), the second hydrogen pressure reducing valve (15), and the hydrogen injector (12), and controls the air supply through the throttle valve (9). It also makes feedback adjustments based on the first hydrogen flow sensor (3), the second hydrogen flow sensor (14), the air flow sensor (10), and the intake pressure sensor (11) to maintain an excess air coefficient λ = 1.2. At the same time, the ECU (29) closes the ammonia pressure reducing valve (5) to ensure that no ammonia fuel is supplied to the engine during startup.

[0041] The ECU (29) receives signals from the speed sensor (27), crankshaft position sensor (28), and intake pressure sensor (11). By controlling the opening of the throttle valve (9), the throttle valve is fully opened, maintaining an excess air coefficient λ = 1.5. At the same time, the volume fraction of ammonia in the total fuel is VNH3 = 60%, so that the engine works under low load conditions. In order to ensure power output and avoid abnormal combustion, a liquid ammonia / hydrogen dual fuel injection strategy is adopted. In order to ensure that the output fuel is liquid ammonia, the pressurized ammonia tank (liquid ammonia) (4) is filled with high-pressure nitrogen. By stabilizing the working pressure of the system, the ammonia pressure reducing valve (5) stabilizes the output of liquid ammonia (pressure value). (Not less than 10 bar) At the same time, the ECU (29) opens the first hydrogen control switch (16) in the P2 pre-stored hydrogen supply system and closes the second hydrogen control switch (17) in the P5 hydrogen oil storage system. The ECU (29) controls the hydrogen supply through the first hydrogen pressure reducing valve (2), the second hydrogen pressure reducing valve (15) and the hydrogen injector (12), controls the air supply through the throttle valve (9), and makes feedback adjustments based on the first hydrogen flow sensor (3), the second hydrogen flow sensor (14) and the air flow sensor (10) and the intake pressure sensor (11). At the same time, the ECU (29) supplies liquid ammonia fuel to the engine through the P3 accumulator ammonia (liquid ammonia) supply system through the ammonia pressure reducing valve (5) and the ammonia injector (7) through the electronic control system, and makes signal feedback corrections through the ammonia flow sensor (6).

[0042] The ECU (29) receives signals from the speed sensor (27), crankshaft position sensor (28) and intake pressure sensor (11), and controls the throttle valve (9) opening to keep the excess air coefficient λ at around 1 to 1.2. At the same time, the volume fraction of ammonia in the total fuel VNH3 is 70% to 90%, so that the engine works under medium and high load conditions. In order to ensure power output and avoid abnormal combustion, a liquid ammonia / hydrogen dual fuel injection strategy is adopted. The ECU (29) uses the electronic control system to keep the first hydrogen control switch (16) in the P2 pre-storage hydrogen supply system closed, while the second hydrogen control switch (17) in the P5 hydrogen oil storage system is open. Through coordinated control with the ECU (29), the temperature sensor detects the exhaust temperature. When the temperature reaches the required temperature (≥200℃) for hydrogen oil and catalyst in the dehydrogenation system reaction device (21), the oil pump (20) pumps the hydrogen oil to the dehydrogenation system reaction device (21) for reaction. The hydrogen oil after the reaction flows back to the hydrogen oil storage tank through the pipeline. The hydrogen produced by the dehydrogenation system reaction device (21) enters the combustion chamber through the third hydrogen flow sensor (24), the second hydrogen pressure reducing valve (15), the second hydrogen flow sensor (14), and the hydrogen injector (12). At the same time, the ECU (29) uses the electronic control system to enable the P3 accumulator ammonia (liquid ammonia) supply system to supply liquid ammonia fuel to the engine through the ammonia pressure reducing valve (5) and ammonia injector (7), and performs signal feedback correction through the ammonia flow sensor (6).

[0043] The excess air coefficient λ of the combustion mixture is the ratio of the actual air requirement to the theoretical air requirement during fuel combustion.

[0044] ammonia fuel volume fraction

[0045] and These represent the volumetric flow rates of NH3 (L / min) and H2 (L / min), respectively.

[0046] (2) Combustion control strategy

[0047] The ECU (29) determines whether abnormal combustion, such as knocking, occurs in the engine cylinder by detecting the signal transmitted by the knock sensor (25). When the smooth cylinder pressure curve of the engine shows a sawtooth shape, or a sharp knocking sound is clearly heard from the engine, it is determined that abnormal combustion has occurred in the engine. If the knock sensor (25) determines that no abnormal combustion, such as knocking, has occurred in the cylinder and the cylinder pressure curve does not show a sawtooth shape, the ECU (29) controls the ignition timing of the spark plug (26) according to the torque demand. When the engine reaches the peak torque, the corresponding ignition timing of the engine is the optimal ignition timing.

[0048] If the knock sensor (25) determines that knocking or other abnormal combustion has occurred in the cylinder, the smooth cylinder pressure curve will show a sawtooth shape. The ECU (29) electronic control system will adjust and delay the ignition timing of the spark plug (26) until the knocking phenomenon is eliminated.

[0049] If delaying the ignition timing to top dead center of the compression cycle still fails to eliminate knocking, the ECU (29) controls the injection quantity of liquid ammonia fuel by controlling the ammonia pressure reducing valve (5) and ammonia injector (7) in the P3 accumulator ammonia supply system, gradually increasing the injection quantity to eliminate knocking. When the knock sensor cannot detect the knocking signal, the ammonia injection quantity remains unchanged under this operating condition.

Claims

1. An ammonia-hydrogen internal combustion engine, characterized in that... include: The engine intake system (P1) includes an air filter (8), a throttle valve (9), an air flow sensor (10), and an intake pressure sensor (11); the pre-stored hydrogen supply system (P2) includes a hydrogen cylinder (1), a first hydrogen pressure reducing valve (2), a first hydrogen flow sensor (3), and a first hydrogen control switch (16); the accumulator ammonia supply system (P3) includes an accumulator ammonia tank (4), an ammonia pressure reducing valve (5), an ammonia flow sensor (6), and an ammonia injector (7); the hydrogen supply system (P4) includes a hydrogen tank (18), a second hydrogen pressure reducing valve (15), a second hydrogen flow sensor (14), a flame arrester (13), and a hydrogen injector (12); the hydrogen oil storage system (P5) includes a hydrogen oil storage tank (19), an oil pump (20), a dehydrogenation system reaction device (21), a temperature sensor (22), a third hydrogen flow sensor (24), and a second hydrogen control switch (17); The ECU control system (P6) includes the ECU (29), oxygen sensor (23), knock sensor (25), spark plug (26), speed sensor (27) and crankshaft position sensor (28). The ECU control system (P6) interacts with the engine intake system (P1) via signals: the ECU (29) is connected to the throttle valve (9) and the air flow sensor (10) via wires; the throttle valve opening is controlled by sending a throttle valve control signal to the throttle valve (9), the intake pressure sensor (11) detects the intake pressure in the intake manifold, and the air flow sensor (10) feeds back the detected signal to the ECU (29) to adjust the engine intake air volume; The ECU control system (P6) interacts with the pre-stored hydrogen supply system (P2): the ECU (29) is connected to the first hydrogen pressure reducing valve (2) via a wire to adjust the hydrogen injection pressure; it is also connected to the first hydrogen flow sensor (3) and the first hydrogen control switch (16) to control the hydrogen flow and hydrogen switch. The ECU control system (P6) interacts with the accumulator ammonia supply system (P3): the ECU (29) is connected to the ammonia pressure reducing valve (5) via a wire, and adjusts the ammonia injection pressure through the throttle control signal and knock signal; at the same time, the wire is also connected to the ammonia flow sensor (6) and the ammonia injector (7). The ECU (29) controls the injection pulse width and injection time through the ammonia injector (7), and corrects it through the feedback signal of the ammonia flow sensor (6); The ECU control system (P6) and the hydrogen supply system (P4) interact with each other: the ECU (29) is connected to the second hydrogen pressure reducing valve (15) via a wire, and adjusts the hydrogen injection pressure through the throttle control signal and the knock signal; at the same time, the wire is also connected to the second hydrogen flow sensor (14) and the hydrogen injector (12). The ECU (29) controls the injection pulse width and injection time through the hydrogen injector (12), and corrects them through the feedback signal of the second hydrogen flow sensor (14); The ECU control system (P6) and the hydrogen oil storage system (P5) interact with each other via signal: the ECU (29) is connected to the oil pump (20), the third hydrogen flow sensor (24), the temperature sensor (22), and the second hydrogen control switch (17) via wires. The ECU (29) controls the hydrogen oil pump (20) to pump hydrogen oil from the hydrogen oil storage tank (19) to the dehydrogenation system reaction device (21). At the same time, the temperature is kept within the reaction temperature range of the dehydrogenation system reaction device (21) by the detection and feedback of the temperature sensor (22). The second hydrogen control switch (17) controls the delivery and shutdown of the hydrogen generated by the dehydrogenation system reaction device (21), and the feedback signal is corrected by the third hydrogen flow sensor (24). Signal interaction exists in the ECU control system (P6): ECU (29) is connected to speed sensor (27) and crankshaft position sensor (28) through wires to determine engine speed and compression pivot position, providing a reference for fuel injection timing and injection pulse width; ECU (29) receives the signal transmitted by oxygen sensor (23) to control the excess air coefficient of the engine; ECU (29) is connected to knock sensor (25) and spark plug (26) through wires to determine whether knock occurs in the cylinder and adjust the ignition timing to avoid knock.

2. The method for controlling an ammonia-hydrogen internal combustion engine as described in claim 1, characterized in that, This method includes fuel supply strategy and combustion control strategy: (1) Fuel supply strategy The ECU (29) receives signals from the speed sensor (27), crankshaft position sensor (28), and intake pressure sensor (11), and controls the throttle valve (9) opening to make the intake pressure 30 kPa. This is the starting condition. In order for the engine to start normally, a pure hydrogen mode combustion strategy is adopted through the pre-hydrogen supply system (P2). The ECU (29) uses the electronic control system to open the first hydrogen control switch (16) in the pre-hydrogen supply system (P2), and at the same time, the hydrogen oil storage system (P5) is activated. The second hydrogen control switch (17) is in the closed state. The ECU (29) controls the hydrogen supply through the first hydrogen pressure reducing valve (2), the second hydrogen pressure reducing valve (15) and the hydrogen injector (12), controls the air supply through the throttle valve (9), and makes feedback adjustments based on the first hydrogen flow sensor (3), the second hydrogen flow sensor (14) and the air flow sensor (10) and the intake pressure sensor (11) to maintain the excess air coefficient λ=1.

2. At the same time, the ECU (29) closes the ammonia pressure reducing valve (5) to ensure that no ammonia fuel is supplied to the engine during the start-up condition. The ECU (29) receives signals from the speed sensor (27), crankshaft position sensor (28) and intake pressure sensor (11), and controls the opening of the throttle valve (9) to make the throttle valve fully open, maintaining an excess air coefficient λ=1.5 and ammonia gas accounting for 60% of the total fuel volume fraction VNH3, so that the engine works under low load conditions. In order to ensure power output and avoid abnormal combustion, a liquid ammonia / hydrogen dual fuel injection strategy is adopted. The ECU (29) uses the electronic control system to open the first hydrogen control switch (16) in the pre-hydrogen supply system (P2) and close the second hydrogen control switch (17) in the hydrogen oil storage system (P5). The ECU (29) controls the hydrogen supply through the first hydrogen pressure reducing valve (2), the second hydrogen pressure reducing valve (15) and the hydrogen injector (12), controls the air supply through the throttle valve (9), and performs feedback adjustment based on the first hydrogen flow sensor (3), the second hydrogen flow sensor (14) and the air flow sensor (10) and the intake pressure sensor (11). At the same time, the ECU (29) uses the electronic control system to supply liquid ammonia fuel to the engine through the ammonia pressure reducing valve (5) and the ammonia injector (7), and performs signal feedback correction through the ammonia flow sensor (6). The ECU (29) receives signals from the speed sensor (27), crankshaft position sensor (28), and intake pressure sensor (11), and controls the throttle valve (9) opening to keep the excess air coefficient λ around 1~1.

2. At the same time, the volume fraction of ammonia in the total fuel VNH3 is 70%~90%, so that the engine works under medium and high load conditions. In order to ensure power output and avoid abnormal combustion, a liquid ammonia / hydrogen dual fuel injection strategy is adopted. The ECU (29) keeps the first hydrogen control switch (16) in the pre-stored hydrogen supply system (P2) in the closed state through the electronic control system, and at the same time, the hydrogen oil storage system (P5) is closed. The second hydrogen control switch (17) is in the open state. Through coordinated control with the ECU (29), the hydrogen generated by the dehydrogenation system reaction device (21) enters the combustion chamber through the third hydrogen flow sensor (24), the second hydrogen pressure reducing valve (15), the second hydrogen flow sensor (14), and the hydrogen injector (12). At the same time, the ECU (29) uses the electronic control system to enable the accumulator ammonia supply system (P3) to supply liquid ammonia fuel to the engine through the ammonia pressure reducing valve (5) and the ammonia injector (7), and performs signal feedback correction through the ammonia flow sensor (6). Among them, the excess air coefficient λ of the combustion mixture is the ratio of the actual air requirement to the theoretical air requirement during fuel combustion; ammonia fuel volume fraction = / ( + ) and These represent the volumetric flow rates of NH3 (L / min) and H2 (L / min), respectively. (2) Combustion control strategy The ECU (29) determines whether knocking occurs in the engine cylinder by detecting the signal transmitted by the knock sensor (25); if the knock sensor (25) determines that no knocking has occurred in the cylinder, the ECU (29) controls the ignition timing of the spark plug (26) by torque demand to keep the ignition timing at the optimal ignition angle. If the knock sensor (25) determines that knocking has occurred in the cylinder, the ECU (29) will delay the ignition timing of the spark plug (26) until the ignition timing of the spark plug (26) is delayed to the top dead center of the compression stroke to eliminate the knocking phenomenon. If delaying the ignition timing to the top dead center of the compression cycle still fails to eliminate knocking, the ECU (29) controls the injection amount of liquid ammonia fuel by controlling the ammonia pressure reducing valve (5) and ammonia injector (7) in the accumulator ammonia supply system (P3), thereby increasing the injection amount to eliminate knocking; when the knocking sensor does not detect the knocking signal, the ammonia injection amount remains unchanged under this condition.

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