Hydrogen engine and power system thereof

Abstract

The hydrogen engine comprises an air cylinder head, an air cylinder, a piston, a high-pressure hydrogen ejector and an air inlet channel communicated with the air cylinder, a combustion chamber is defined by the air cylinder head, the air cylinder and the piston, and the high-pressure hydrogen ejector is arranged on the side face of the air cylinder head and communicated with the combustion chamber; an included angle is formed between the axis of the high-pressure hydrogen ejector and the air inlet channel, so that hydrogen ejected by the high-pressure hydrogen ejector impacts the side face of an air tumble mass in the air cylinder. In the invention, high-speed uniform mixing of air and hydrogen is realized in a manner that the ejected hydrogen impacts the side surface of the air tumble group, so that the concentration of the mixed gas in the cylinder is uniform, abnormal combustion phenomena such as preignition, detonation and post-combustion caused by non-uniform concentration of the mixed gas in the cylinder are effectively inhibited, the combustion is stable and sufficient, and the service life of the cylinder is prolonged. And the heat efficiency of the hydrogen engine is improved. The invention further provides a power system based on the hydrogen engine.

Description

Technical Field

[0001] The invention relates to a hydrogen engine, in particular to a hydrogen engine with direct injection in a cylinder and a power system thereof. Background Art

[0002] Hydrogen does not contain carbon, so it does not produce CO2 after combustion. In addition, hydrogen can be obtained through renewable energy sources such as solar energy and wind energy, and is considered to be an ideal energy source or energy carrier. When hydrogen is used as a fuel for internal combustion engines, it is very easy to achieve lean combustion, emit less pollutants, and have high thermal efficiency. Existing hydrogen engines can be divided into two types according to their hydrogen supply method: intake port injection and direct injection. Intake port injection can directly use existing natural gas injectors as fuel modification, which has the advantages of low cost and mature technology. However, the volume energy density of hydrogen is small, resulting in the performance of hydrogen engines being far lower than that of gasoline engines of the same displacement. In addition, hydrogen has the characteristics of a wide flammable range and low ignition energy, which makes hydrogen engines with intake port injection prone to abnormal combustion phenomena such as backfire, pre-ignition and detonation. The use of a direct injection fuel supply solution can completely solve the problem of backfire.

[0003] For example, Chinese patent document CN221096665U discloses a direct-injection hydrogen engine and a car, which includes a cylinder head, a cylinder, a piston, a spark plug, an intake valve and an exhaust valve. The cylinder head, the cylinder and the piston enclose a combustion chamber, the cylinder head is connected to the spark plug, the intake valve and the exhaust valve, and the piston top surface is provided with a guide portion, which is used to guide the flow of hydrogen in the combustion chamber; the guide portion is provided with an avoidance groove, which is arranged corresponding to at least one of the spark plug, the intake valve and the exhaust valve, and the avoidance groove is used to avoid interference between the guide portion and at least one of the spark plug, the intake valve and the exhaust valve. The guide portion cooperates with the cylinder wall of the cylinder to guide the direction of the hydrogen beam and organize the spatial position of the beam, so that the hydrogen beam injected into the combustion chamber is consistent with the direction of the macroscopic airflow movement in the cylinder, promotes the coordination of hydrogen with the overall tumble flow in the cylinder, enhances the turbulent kinetic energy in the cylinder, and realizes the organization of the high-concentration area near the spark plug, and promotes the rapid development of the flame.

[0004] However, in the prior art, the movement direction of the hydrogen jet ejected from the hydrogen nozzle is the tangential direction of the tumbling air in the cylinder, which can easily lead to the problem that the mixture on the intake and exhaust sides of the cylinder is relatively rich while the mixture on the left and right sides is relatively thin. After the spark plug is ignited, the thicker mixture on the intake and exhaust sides is likely to spontaneously ignite before the flame front reaches it, causing detonation, while the thinner mixture on the left and right sides may have a slow flame propagation speed and go out, resulting in a large amount of unburned mixture in the exhaust, abnormal combustion phenomena such as afterburning and backfire, resulting in insufficient performance and low thermal efficiency. Summary of the invention

[0005] In order to solve the technical problem of abnormal combustion caused by uneven concentration of mixed gas in the cylinder in the prior art, the present invention provides a hydrogen engine, including a cylinder head, a cylinder, a piston, a high-pressure hydrogen injector and an intake duct connected to the cylinder, the cylinder head, the cylinder and the piston enclose a combustion chamber, the high-pressure hydrogen injector is arranged on the side of the cylinder head and is connected to the combustion chamber; wherein: the axis of the high-pressure hydrogen injector is arranged at an angle with the intake duct so that the hydrogen sprayed by the high-pressure hydrogen injector hits the side of the air tumble group in the combustion chamber.

[0006] In the prior art, since the direction of the hydrogen jet is tangent to the air tumble group in the combustion chamber, when the hydrogen jet passes through the air tumble group, the mixture concentration in the intake area is relatively high, while the mixture concentration in the left and right areas is relatively low. In this solution, the position of the high-pressure hydrogen injector is reset so that the hydrogen ejected by the high-pressure hydrogen injector is no longer tangent to the air tumble group, but the ejected hydrogen can hit the side of the air tumble group. When the hydrogen hits the air, the air in the combustion chamber and the hydrogen ejected by the high-pressure hydrogen injector are mixed at a high speed, so that the mixture concentration in the combustion chamber is uniform, avoiding abnormal combustion caused by uneven mixture concentration, thereby avoiding the problem of insufficient engine performance and low thermal efficiency.

[0007] Preferably, the axis of the high-pressure hydrogen injector and the plane formed by the straight line projected by the high-pressure hydrogen injector on the bottom surface of the cylinder head are arranged perpendicularly to the plane of the central axis of the intake passage. In this solution, the vertical arrangement of the two planes can ensure that the hydrogen ejected by the high-pressure hydrogen injector can hit the side of the air tumble group in the combustion chamber, without the need to add an additional guide structure, the structure is simple, and the cost of the hydrogen engine can be reduced.

[0008] Preferably, a spark plug is provided on the cylinder head, and a guide is provided at the tail end of the high-pressure hydrogen injector to direct the injection direction of the high-pressure hydrogen injector toward the spark plug electrode. In this solution, the guide is used to direct the injection direction of the high-pressure hydrogen toward the spark plug electrode, which can ensure that there is a sufficient concentration of mixed gas near the spark plug electrode, thereby avoiding misfires and further ensuring the normal use of the hydrogen engine.

[0009] Preferably, the guide member is a guide cap with an injection hole, and the injection hole of the guide cap is arranged at an angle with the injection hole of the high-pressure hydrogen injector. In this solution, the injection direction of the high-pressure hydrogen is guided by utilizing the positional relationship between the injection hole of the guide cap and the injection hole of the high-pressure hydrogen injector, which has a simple structure and can reduce the cost of the hydrogen engine.

[0010] Preferably, the angle between the injection hole of the guide cap and the injection hole of the high-pressure hydrogen injector is 10° to 30°. This solution can ensure that the injected high-pressure hydrogen is guided to the vicinity of the spark plug electrode, has a simple structure, and can reduce the cost of the hydrogen engine.

[0011] Preferably, the hydrogen engine is suitable for a two-cylinder engine, and further comprises a timing chain, which is arranged between the two cylinders, and high-pressure hydrogen injectors are respectively arranged on the left and right sides of the cylinder head. This solution can effectively utilize the idle space on the left and right sides of the cylinder head.

[0012] In a second aspect, the present invention provides a power system of a hydrogen engine, wherein: the above-mentioned hydrogen engine is adopted, including a control system, an intake valve is provided in the intake duct, and the control system controls the high-pressure hydrogen injector to start spraying hydrogen after the intake valve is closed.

[0013] In an engine with intake duct injection, if the mixture after combustion flows back into the intake duct, it is easy to ignite the fresh mixture in the intake duct and cause backfire. Therefore, in this scheme, the hydrogen injection operation is performed after the intake valve is closed. This can prevent the mixture from flowing back into the intake duct and causing backfire, further ensuring the normal use of the hydrogen engine.

[0014] Preferably, the control system includes a cam position sensor, which is arranged on the cylinder head cover of the cylinder. In this solution, the cam position sensor is arranged to detect different strokes of the cylinder to ensure that hydrogen injection can be performed during the compression stroke, further ensuring the normal use of the hydrogen engine.

[0015] Preferably, the high-pressure hydrogen injector is connected to a high-pressure hydrogen supply system with an injection pressure reaching the MPa level. In this solution, after the injection pressure of the high-pressure hydrogen supply system reaches the MPa level, the hydrogen injection pressure can be greater than the cylinder pressure after the intake valve is closed, and a sufficient amount of hydrogen can be injected into the cylinder in a short time, shortening the hydrogen injection pulse width, thereby extending the mixing time of air and hydrogen, and allowing air and hydrogen to be more fully mixed, thereby suppressing abnormal combustion caused by uneven concentration of the mixed gas in the cylinder, and ensuring the normal use of the hydrogen engine.

[0016] The present invention has the following beneficial effects: 1. In the present invention, the ejected hydrogen is used to collide with the side of the air tumble group to achieve high-speed uniform mixing of air and hydrogen, so that the concentration of the mixed gas in the combustion chamber is uniform, and abnormal combustion phenomena such as pre-ignition, detonation and backfire caused by uneven concentration of the mixed gas in the combustion chamber are effectively suppressed. The combustion is stable and sufficient, and the thermal efficiency of the hydrogen engine is improved.

[0017] 2. The present invention can solve the abnormal combustion problem of backfire in hydrogen engines and ensure the normal use of hydrogen engines.

[0018] 3. The present invention can effectively utilize the idle space on the left and right sides of the cylinder head, while meeting the needs of single-cylinder and dual-cylinder structures. It can also eliminate the problem of complex cylinder head structure occupying intake duct space caused by arranging the high-pressure hydrogen injector below the intake duct. The present invention has a simple structure and has the advantages of low production cost and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of a hydrogen engine in an embodiment of a hydrogen engine and a power system thereof of the present invention; Figure 2 for Figure 1 A cross-sectional view of Figure 3 It is a partial structural schematic diagram of a hydrogen engine; Figure 4 is a schematic diagram of a camshaft position sensor and a position signal wheel; Figure 5 It is a partial schematic diagram of the cylinder head cover part in the hydrogen engine; Figure 6 A schematic diagram of the position layout between the intake pipe and the high-pressure hydrogen injector; Figure 7 This is the structural block diagram of the power system. DETAILED DESCRIPTION

[0020] The following is further described in detail through specific implementation methods: 1. Definition Tumble flow: The organized air swirl formed around the cylinder axis perpendicular to the cylinder axis during the intake process is called tumble flow.

[0021] Timing chain: The main function is to drive the engine's valve mechanism so that the engine's intake and exhaust valves open or close at the appropriate time to ensure that the engine cylinders can inhale and exhaust normally.

[0022] The compression stroke of the cylinder is the stroke that converts mechanical energy into internal energy. During compression, the piston moves from the bottom dead center to the top dead center.

[0023] Cam position sensor: A sensing device, also called a synchronous signal sensor, which is a cylinder identification and positioning device that inputs camshaft position signals to the ECU.

[0024] 2. The reference numerals in the drawings of the specification include: cylinder head cover 1, cylinder head 2, timing chain 3, cylinder 4, high-pressure hydrogen injector 5, camshaft position sensor 6, spark plug 7, position signal wheel 8, convex tooth 9, guide cap 10, intake duct 11, air tumble group 12, high-speed hydrogen flow 13, plane A14, plane B15.

[0025] The embodiment is basically as shown in the attached Figure 1-Figure 6As shown: a hydrogen engine, including a cylinder 4, a cylinder head, a piston, a camshaft, a high-pressure hydrogen injector 5 and an intake passage 11 connected to the cylinder 4, the cylinder head, the cylinder and the piston enclose a combustion chamber, a position signal wheel 8 is provided on the camshaft, the high-pressure hydrogen injector 5 is arranged on the side of the cylinder head 2 and is connected to the combustion chamber, and a spark plug 7 is provided on the cylinder head 2.

[0026] The axis of the high-pressure hydrogen injector 5 is set at an angle to the intake duct 11 so that the hydrogen ejected from the high-pressure hydrogen injector 5 hits the side of the air tumble group 12 in the combustion chamber. Specifically, the plane A14A formed by the axis of the high-pressure hydrogen injector 5 and the straight line projected by the high-pressure hydrogen injector 5 on the bottom surface of the cylinder head 2 is perpendicular to the center axis plane B15 of the intake duct 11, as shown in FIG. Figure 6 shown.

[0027] The tail end of the high-pressure hydrogen injector 5 is provided with a guide member for guiding the injection direction of the high-pressure hydrogen injector 5 toward the electrode of the spark plug 7. Specifically, the guide member is a guide cap 10 with an injection hole. The injection hole of the guide cap 10 is arranged at an angle of 10° to 30° with the injection hole of the high-pressure hydrogen injector 5. Figure 5 shown.

[0028] In this embodiment, the hydrogen engine is suitable for a two-cylinder engine, and the cylinder 4 can also be set to two, and a timing chain 3 is provided between the two cylinders 4, such as Figure 3 The high-pressure hydrogen injectors 5 are arranged on the left and right sides of the cylinder head 2 respectively.

[0029] like Figure 7 As shown, based on the above hydrogen engine, this embodiment also discloses a power system of a hydrogen engine, including a control system and a high-pressure hydrogen supply system with an injection pressure reaching the MPa level, and a high-pressure hydrogen injector 5 is connected to the high-pressure hydrogen supply system. The control system includes a cam position sensor, which is arranged on the cylinder head cover 1 of the cylinder 4, and an intake valve is arranged in the intake passage 11. The control system controls the high-pressure hydrogen injector 5 to start spraying hydrogen after the compression stroke of the cylinder 4 and the intake valve is closed.

[0030] Specifically, Figure 4 As shown, the camshaft position sensor 6 is located directly above the position signal wheel 8, and a certain air gap is provided between the camshaft position sensor 6 and the convex tooth 9 of the position signal wheel 8. There is at least one convex tooth 9 on the position signal wheel 8. As the camshaft rotates, the gap between the camshaft position sensor 6 and the shaft position signal wheel 8 changes periodically, and a periodic square wave signal is output. According to the square wave signal, it can be determined at which stroke stage the cylinder 4 is currently working.

[0031] The specific implementation process is as follows: During operation, the camshaft rotates, the cylinder 4 works, and the air enters the combustion chamber through the intake valve, forming an air tumble group 12. As the camshaft rotates, the gap between the camshaft position sensor 6 and the shaft position signal wheel 8 changes periodically, and a periodic square wave signal is output. According to the square wave signal, it can be determined which stroke stage the engine is currently working in. The high-pressure hydrogen supply system provides high-pressure hydrogen, and the control system controls the high-pressure hydrogen injector 5 to start spraying hydrogen after the compression stroke and the intake valve are closed. The high-speed hydrogen flow 13 ejected by the high-pressure hydrogen injector 5 collides with the side of the air tumble group 12 in the combustion chamber, so that the air and hydrogen in the combustion chamber can be quickly and evenly mixed, and the abnormal combustion phenomenon caused by the uneven concentration of the mixed gas in the combustion chamber is suppressed. At the same time, the injection hole of the guide cap 10 will point the high-pressure hydrogen injection direction to the electrode of the spark plug 7, ensuring that there is a sufficient concentration of mixed gas near the electrode of the spark plug 7 to avoid misfires.

[0032] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can know all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A hydrogen engine, comprising a cylinder head, a cylinder, a piston, a high-pressure hydrogen injector and an intake passage connected to the cylinder, wherein the cylinder head, the cylinder and the piston enclose a combustion chamber, and the high-pressure hydrogen injector is arranged on the side of the cylinder head and connected to the combustion chamber; characterized in that: The axis of the high-pressure hydrogen injector is arranged at an angle with the intake passage so that the hydrogen sprayed by the high-pressure hydrogen injector hits the side of the air tumble group of the combustion chamber.

2. The hydrogen engine according to claim 1, characterized in that: The axis of the high-pressure hydrogen injector and the plane formed by the straight line projected by the high-pressure hydrogen injector on the bottom surface of the cylinder head are arranged perpendicular to the plane of the central axis of the intake passage.

3. The hydrogen engine according to claim 1 or 2, characterized in that: The cylinder head is provided with a spark plug, and the tail end of the high-pressure hydrogen injector is provided with a guide member for guiding the injection direction of the high-pressure hydrogen injector toward the spark plug electrode.

4. The hydrogen engine according to claim 3, characterized in that: The guide member is a guide cap with a spray hole, and the spray hole of the guide cap is arranged at an angle with the spray hole of the high-pressure hydrogen injector.

5. The hydrogen engine according to claim 4, characterized in that: The included angle between the injection hole of the guide cap and the injection hole of the high-pressure hydrogen injector is 10° to 30°.

6. The hydrogen engine according to claim 5, characterized in that: The hydrogen engine is suitable for a two-cylinder engine and further comprises a timing chain, wherein the timing chain is arranged between two cylinders, and the high-pressure hydrogen injectors are respectively arranged on the left and right sides of the cylinder head.

7. A power system of a hydrogen engine, characterized in that: The hydrogen engine according to any one of claims 1 to 5 comprises a control system, wherein an intake valve is provided in the intake passage, and the control system controls the high-pressure hydrogen injector to start spraying hydrogen after the intake valve is closed.

8. The power system of the hydrogen engine according to claim 7, characterized in that: The control system controls the high-pressure hydrogen injector to start injecting hydrogen after the compression stroke of the cylinder and the closing of the intake valve.

9. The power system of the hydrogen engine according to claim 8, characterized in that: A cylinder head cover is also included, and the control system includes a cam position sensor, which is arranged on the cylinder head cover.

10. The power system of the hydrogen engine according to claim 9, characterized in that: The high-pressure hydrogen injector is connected to a high-pressure hydrogen supply system with an injection pressure reaching MPa level.

Images