Ammonia-hydrogen fusion efficient engine combustion system and strategy
By arranging the pre-combustion chamber in the middle of the main combustion chamber in the ammonia-hydrogen fusion engine, and by adopting an optimized combustion strategy and injection angle, the problems of pre-combustion chamber space limitation and excessive temperature are solved, combustion efficiency and flame propagation speed are improved, and the combustion reliability of the engine under different operating conditions is enhanced.
Patent Information
- Application Number
- CN202511216017.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-28
- Publication Date
- 2025-11-28
AI Technical Summary
In existing ammonia-hydrogen fusion engines, the jet pre-combustion chamber is installed on top of the main combustion chamber, encroaching on the space for the intake and exhaust valves. This results in a reduction in valve diameter, decreased charging efficiency, and excessively high combustion temperature in the pre-combustion chamber, which shortens the service life.
The pre-combustion chamber is located in the middle of the main combustion chamber. The top of the main combustion chamber is equipped with a relatively inclined surface and a liquid ammonia injector. The premixed and non-premixed combustion methods are adopted, combined with hydrogen injection and spark plug ignition, and the combustion chamber design and injection angle are optimized.
It solves the problem of limited space in the pre-combustion chamber, improves combustion efficiency and flame propagation speed, ensures uniform combustion, and enhances the combustion reliability and charging efficiency of the engine under different operating conditions.
Smart Images
Figure CN121024752A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to ammonia-hydrogen hybrid engine combustion technology, more particularly, it relates to an ammonia-hydrogen hybrid high-efficiency engine combustion system and strategy. BACKGROUND
[0002] Zero-carbon fuel ammonia is an important means of reducing carbon emissions for commercial vehicles. Traditional internal combustion engines use gasoline, diesel and other carbon-containing fuels, which produce a large amount of carbon dioxide emissions during combustion. In order to reduce greenhouse gas emissions, low-carbon / zero-carbon fuel replacement solutions are urgently needed. Ammonia (NH3) as a zero-carbon fuel, the combustion product is only nitrogen and water, and has the convenience of storage and transportation, is an ideal alternative fuel. However, it has two inherent defects: the flame propagation speed is extremely low, resulting in low combustion efficiency; difficult to ignite, especially at low temperature conditions, the misfire rate is high. Using hydrogen gas jet flame in the pre-chamber to ignite the ammonia in the main combustion chamber can solve the problem of unstable ignition of ammonia-fueled internal combustion engines, but the jet pre-chamber is installed on the top of the main combustion chamber, which occupies the layout space of the intake and exhaust valves, resulting in a decrease in valve diameter, reducing the charging efficiency and limiting the expansion of the lean burn limit. SUMMARY
[0003] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art, and to provide an ammonia-hydrogen hybrid high-efficiency engine combustion system and strategy, which solves the technical problem of the prior art that the jet pre-chamber is installed on the top of the main combustion chamber, which occupies the layout space of the intake and exhaust valves, and the combustion temperature in the pre-chamber is too high, which shortens the service life of the pre-chamber.
[0004] The ammonia-hydrogen hybrid high-efficiency engine combustion system comprises a main combustion chamber, a pre-chamber, two intake valves and two exhaust valves, the pre-chamber is arranged at the middle position of the main combustion chamber, the top profile of the main combustion chamber comprises a first inclined surface and a second inclined surface arranged oppositely, two intake valves are arranged on the first inclined surface, two exhaust valves are arranged on the second inclined surface, the bottom of the main combustion chamber is composed of the top arc surface of the piston, and two liquid ammonia injectors are arranged above the main combustion chamber.
[0005] Further improvement, a hydrogen injection valve for injecting hydrogen and a spark plug for igniting hydrogen are installed in the pre-chamber.
[0006] Further, the injection angle of the two liquid ammonia injectors is 45°-75°.
[0007] Further, the jet flame angle of the pre-chamber is 90°-120°.
[0008] A strategy for using the above-mentioned ammonia-hydrogen hybrid high-efficiency engine combustion system, the strategy being: obtaining an engine operating condition, when the engine operating condition is a first operating condition, triggering a premixed combustion method to control the liquid ammonia injector to inject liquid ammonia; when the engine operating condition is a second operating condition, triggering a non-premixed combustion method to control the liquid ammonia injector to inject liquid ammonia; the liquid ammonia is vaporized into liquid ammonia spray, a small amount of hydrogen gas is sprayed by the hydrogen injection valve, the spark plug ignites the hydrogen gas in the pre-chamber to form a jet flame, and the jet flame ignites the liquid ammonia spray in the main combustion chamber to start the engine.
[0009] Further improvement, the premixed combustion method is that the liquid ammonia injector sprays liquid ammonia into the cylinder one or more times during the engine intake or compression stroke, so that the liquid ammonia and air are fully mixed before combustion to achieve homogeneous combustion.
[0010] Further, the non-premixed combustion method is that the liquid ammonia injector directly sprays liquid ammonia to achieve diffusion combustion.
[0011] Further, when the engine operating condition is a transient change condition, the liquid ammonia injector directly sprays liquid ammonia according to adjustable injection parameters, ammonia injection amount and injection timing.
[0012] Further, the first operating condition is a stable low-medium load stage or a cold start and warm-up stage.
[0013] Further, the second operating condition is a high load condition or an acceleration condition or a transient change condition or an extreme condition.
[0014] Advantages
[0015] The advantages of the present application are:
[0016] 1. The present application provides a main combustion chamber, a pre-chamber, two intake valves and two exhaust valves, the pre-chamber is arranged in the middle position of the main combustion chamber, the top profile of the main combustion chamber includes a first inclined surface and a second inclined surface arranged oppositely, the two intake valves are arranged on the first inclined surface, the two exhaust valves are arranged on the second inclined surface, and the bottom of the main combustion chamber is composed of the top arc surface of the piston. This design of the main combustion chamber with a tented roof effectively solves the problem of limited installation space of the pre-chamber and the liquid ammonia injector, and avoids the problem of too small diameter of the intake and exhaust valves leading to expansion of the limit of lean burn index.
[0017] 2. The present invention arranges two liquid ammonia injectors above the main combustion chamber, which can ensure that the liquid ammonia spray can be evenly and symmetrically distributed in the main combustion chamber, and ensure that the flame propagation can quickly fill the entire combustion chamber; the liquid ammonia spray and the jet flame of the pre-combustion chamber can quickly come into contact, ensuring that all liquid ammonia spray bundles are ignited at the first time, thus ensuring the flame propagation speed; the liquid ammonia spray and the intake tumble flow of the intake duct are in the vertical direction, which can form a pulse effect, which is beneficial to the mixing of fuel and air under premixed injection conditions. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the ammonia-hydrogen fusion high-efficiency engine combustion system of the present invention;
[0019] Figure 2 This is a first cross-sectional view of the main combustion chamber of the present invention;
[0020] Figure 3 This is a second cross-sectional view of the main combustion chamber of the present invention.
[0021] Wherein: 1-Liquid ammonia injector, 2-Hydrogen injection valve, 3-Exhaust duct, 4-Intake duct, 5-Pre-combustion chamber, 6-Spark plug, 7-Pre-combustion chamber, 8-Main combustion chamber, 9-Intake valve, 10-Exhaust valve, 11-First inclined surface, 12-Second inclined surface. Detailed Implementation
[0022] The present invention will be further described below with reference to embodiments, but this does not constitute any limitation on the present invention. Any limited modifications made by any person within the scope of the claims of the present invention are still within the scope of the claims of the present invention.
[0023] See Figures 1-3 The present invention discloses an ammonia-hydrogen fusion high-efficiency engine combustion system, which includes a main combustion chamber 8, a pre-combustion chamber 5, two intake valves 9, and two exhaust valves 10. The pre-combustion chamber 5 is arranged in the middle of the main combustion chamber 8. Figure 3 As shown, the top profile of the main combustion chamber 8 includes a first inclined surface 11 and a second inclined surface 12 arranged opposite to each other. Two intake valves 9 are spaced apart on the first inclined surface 11, and two exhaust valves 10 are spaced apart on the second inclined surface 12. The bottom of the main combustion chamber 8 is formed by the piston top arc surface, and two liquid ammonia injectors 1 are arranged above the main combustion chamber 8. This canopy-type main combustion chamber design effectively solves the limitation of installation space for the pre-combustion chamber 5 and the liquid ammonia injectors, avoiding the problem of lean-burn index limit expansion due to the small diameter of the intake valves 9 and exhaust valves 10.
[0024] This invention arranges two liquid ammonia injectors 1 on the main combustion chamber 8, which respectively spray high-pressure liquid ammonia from one side. Figure 2As shown, the fuel for the main combustion chamber 8 to burn; hydrogen injection valve 2 and spark plug 6 are arranged in the middle of the pre-chamber 5, hydrogen injection valve 2 sprays a small amount of hydrogen in the pre-chamber 5, spark plug 6 ignites hydrogen in the pre-chamber 5 to form a jet flame, the jet flame sprays out of the pre-chamber 5 under the action of the pressure difference between the pre-chamber 5 and the main combustion chamber 8, and ignites the liquid ammonia spray that has been gasified by the liquid ammonia injector 1 arranged on both sides.
[0025] As shown in Figure 2 The spray angle of the two liquid ammonia injectors 1 is "A", and "A" is between 45° and 75°. If "A" is less than 45 degrees, it will affect the atomization effect of the liquid ammonia spray, which will cause the combustion efficiency to decrease. If "A" is greater than 75 degrees, the liquid ammonia spray will collide with the combustion chamber and the piston wall, causing fuel wetting, uneven in-cylinder mixture in the premixing strategy, and affecting the development of the flame front in the diffusion combustion strategy; cooperate with the angle distribution of the liquid ammonia spray.
[0026] As shown in Figure 2 The jet flame angle "B" of the pre-chamber 5 is between 90° and 120°, which ensures that all liquid ammonia sprays can be completely ignited.
[0027] The main combustion chamber 8 is arranged with two liquid ammonia injectors 1, which has three advantages: first, it can ensure that the liquid ammonia spray is evenly distributed in the main combustion chamber 8, ensuring that the flame propagation can quickly fill the entire combustion chamber; second, the liquid ammonia spray and the jet flame of the pre-chamber 5 can quickly contact, ensuring that all liquid ammonia spray beams are ignited at the first time, ensuring the flame propagation speed; third, the liquid ammonia spray and the intake swirl in the vertical direction can form a pulse effect, which is beneficial to the mixing of fuel and air in the premixing injection working condition.
[0028] A strategy for applying the above-mentioned ammonia-hydrogen hybrid high-efficiency engine combustion system, which is, obtaining engine working conditions, when the engine working conditions are stable medium and low load or cold start and warm-up stage, triggering the premixed combustion method; when the engine working conditions are high load working conditions or acceleration working conditions or transient change working conditions or extreme condition working conditions, triggering the non-premixed combustion method, liquid ammonia is gasified into liquid ammonia spray, hydrogen injection valve 2 sprays a small amount of hydrogen, spark plug 6 ignites hydrogen in pre-chamber 5 to form jet flame, jet flame ignites liquid ammonia spray in main combustion chamber 8 to start engine.
[0029] Premixed combustion method:
[0030] When the engine working condition is stable medium and low load stage: At this time, the engine demand is stable, the liquid ammonia of the liquid ammonia injector 1 is sprayed into the cylinder once or multiple times during the engine intake or compression stroke, and the ammonia and air are fully mixed before combustion, which can realize homogeneous combustion, improve thermal efficiency and reduce emissions.
[0031] When the engine operating condition is cold start and warm-up stage: pre-mixing helps to quickly establish stable combustion and avoid ignition failure of ammonia. At the same time, increase the proportion of hydrogen energy to compensate for the inertness of ammonia combustion at low temperature.
[0032] Non-premixed combustion method:
[0033] Direct injection of liquid ammonia by controlling liquid ammonia injector 1 to achieve diffusion combustion.
[0034] When the engine operating condition is high load or acceleration condition: the non-premixed combustion method (diffusion combustion) directly injects liquid ammonia by controlling the liquid ammonia injector 1 to achieve fuel stratification, providing fast torque response.
[0035] When the engine operating condition is transient change scenario (such as load sudden increase or deceleration): allow flexible adjustment of injection parameters, hydrogen injection amount and timing, compensate for the slow combustion characteristics of ammonia, so as to prevent misfire or knock.
[0036] When the engine operating condition is extreme condition (such as high altitude or low temperature environment) condition: the non-premixed combustion method enhances the reliability of combustion and reduces the problem of mixture caused by thin air.
[0037] Operating condition switching: based on the preset engine MAP (speed-load matrix), the ECU adopts the premixed combustion method or the non-premixed combustion method in real time.
[0038] The above is only the preferred embodiment of the present application, it should be noted that for those skilled in the art, without departing from the structure of the present application, can also make several variations and improvements, these will not affect the effect of the present application and the practicality of the patent.
Claims
1. A high-efficiency combustion system for an ammonia-hydrogen fusion engine, characterized in that, The system includes a main combustion chamber (8), a pre-combustion chamber (5), two intake valves (9) and two exhaust valves (10). The pre-combustion chamber (5) is located in the middle of the main combustion chamber (8). The top profile of the main combustion chamber (8) includes a first inclined surface (11) and a second inclined surface (12) arranged opposite to each other. The two intake valves (9) are arranged at intervals on the first inclined surface (11), and the two exhaust valves (10) are arranged at intervals on the second inclined surface (12). The bottom of the main combustion chamber (8) is formed by the piston top arc surface. Two liquid ammonia injectors (1) are arranged above the main combustion chamber (8).
2. The ammonia-hydrogen fusion high-efficiency engine combustion strategy according to claim 1, characterized in that, The pre-combustion chamber (5) is equipped with a hydrogen injection valve (2) for injecting hydrogen and a spark plug (6) for igniting hydrogen.
3. The ammonia-hydrogen fusion high-efficiency engine combustion system according to claim 1, characterized in that, The injection angles of the two liquid ammonia injectors (1) are 45° to 75°.
4. The ammonia-hydrogen fusion high-efficiency engine combustion system according to claim 1, characterized in that, The jet flame angle of the pre-combustion chamber (5) is 90° to 120°.
5. A strategy for applying the ammonia-hydrogen fusion high-efficiency engine combustion system according to any one of claims 1-4, characterized in that, The strategy is as follows: when the engine operating condition is the first operating condition, a premixed combustion method is triggered to control the liquid ammonia injector (1) to inject liquid ammonia; when the engine operating condition is the second operating condition, a non-premixed combustion method is triggered to control the liquid ammonia injector (1) to inject liquid ammonia; the liquid ammonia is vaporized into liquid ammonia spray, the hydrogen injection valve (2) sprays out a small amount of hydrogen, the spark plug (6) ignites the hydrogen in the pre-combustion chamber (5) to form a jet flame, and the jet flame ignites the liquid ammonia spray in the main combustion chamber (8) to start the engine.
6. The ammonia-hydrogen fusion high-efficiency engine combustion strategy according to claim 5, characterized in that, The premixed combustion method involves injecting liquid ammonia into the cylinder once or multiple times during the engine intake or compression stroke, so that the liquid ammonia and air are fully mixed before combustion to achieve homogeneous combustion.
7. The ammonia-hydrogen fusion high-efficiency engine combustion strategy according to claim 5, characterized in that, The non-premixed combustion method is that the liquid ammonia injector (1) directly injects liquid ammonia to achieve diffusion combustion.
8. The ammonia-hydrogen fusion high-efficiency engine combustion strategy according to claim 7, characterized in that, When the engine operating condition is a transient change condition, the liquid ammonia injector (1) is controlled to directly inject liquid ammonia according to the adjustable injection parameters, ammonia injection quantity and injection timing.
9. The ammonia-hydrogen fusion high-efficiency engine combustion strategy according to claim 5, characterized in that, The first operating condition is a stable low-to-medium load phase or a cold start and warm-up phase.
10. The ammonia-hydrogen fusion high-efficiency engine combustion strategy according to claim 5, characterized in that, The second operating condition is a high-load stage, an acceleration stage, a transient change stage, or an extreme condition.