Air inlet cam, combustion system and engine

Abstract

The utility model discloses an admission cam, combustion system and engine, the cam profile of admission cam includes: base circle and cam peach portion, and the two endpoints of base circle coincide with the two endpoints of cam peach portion respectively, and the two endpoints of cam peach portion are opening endpoint and closing endpoint respectively, the cam peach part comprises a buffering opening section, a working section and a buffering closing section, the buffering opening section is connected with the opening end point, the buffering closing section is connected with the closing end point, the working section is located between the buffering opening section and the buffering closing section, and the buffering opening section and the buffering closing section are both linear sections; wherein the wrap angle of the buffer opening section is theta1, 7 degrees < = theta1 < = 10 degrees, the wrap angle of the working section is theta2, 90 degrees < = theta2 < = 110 degrees, the wrap angle of the buffer closing section is theta3, 14 degrees < = theta3 < = 18 degrees. According to the utility model, the air inlet is opened earlier, and the air inlet is closed earlier under the condition that the wrap angle of the working section is not changed all the time, so that the probability that mixed gas flows back to the air inlet channel is reduced, and the combustion is more stable.

Description

Technical Field

[0001] The utility model relates to the technical field of engines, and in particular to an intake cam, a combustion system and an engine. Background Art

[0002] In the related art, a hydrogen engine uses hydrogen as fuel. When the air intake in the hydrogen engine is closed, the mixed gas in the combustion cylinder flows back into the intake duct, causing instability in the next combustion. Utility Model Content

[0003] In view of this, the utility model aims to provide an intake cam.

[0004] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0005] An intake cam, the cam profile of the intake cam comprises: a base circle and a cam lobe, and the two endpoints of the base circle coincide with the two endpoints of the cam lobe respectively, the two endpoints of the cam lobe are an opening endpoint and a closing endpoint respectively, the cam lobe comprises a buffer opening section, a working section, and a buffer closing section, the buffer opening section is connected to the opening endpoint, the buffer closing section is connected to the closing endpoint, the working section is located between the buffer opening section and the buffer closing section, and the buffer opening section and the buffer closing section are both straight line sections; wherein the wrap angle of the buffer opening section is θ1, 7°≤θ1≤10°, the wrap angle of the working section is θ2, 90°≤θ2≤110°, and the wrap angle of the buffer closing section is θ3, 14°≤θ3≤18°.

[0006] According to the intake cam of the embodiment of the utility model, the intake port is opened earlier, and when the wrap angle of the working section remains unchanged, the intake port is closed earlier, which reduces the probability of the mixture flowing back to the intake duct and makes the combustion more stable.

[0007] In addition, the intake cam according to the above embodiment of the utility model may also have the following additional technical features:

[0008] According to some embodiments of the present invention, the lift of the buffer opening section is h1, 0mm≤h1≤0.05mm.

[0009] According to some embodiments of the present invention, the lift of the buffer closing section is h2, 0mm≤h2≤0.1mm.

[0010] According to some embodiments of the present invention, the lift of the working section is h3, 3.5mm≤h3≤4.5mm.

[0011] According to some embodiments of the present utility model, the lift of the working section is 4.13 mm, the lift of the buffer opening section is 0.03 mm, and the lift of the buffer closing section is 0.09 mm.

[0012] According to some embodiments of the present invention, the radius of the base circle is R, 15.5 mm ≤ R ≤ 17.5 mm.

[0013] According to some embodiments of the present invention, θ1 is 9.5°, θ2 is 103.5°, and θ3 is 16°.

[0014] Another object of the present invention is to provide a combustion system.

[0015] According to the combustion system of the embodiment of the utility model, it includes: a combustion cylinder, the combustion cylinder has an intake port and an exhaust port; a piston, the piston is movably installed in the combustion cylinder; a crankshaft, the crankshaft is connected to the piston to drive the piston to move; a hydrogen injector, the hydrogen injector is arranged in the combustion cylinder to inject hydrogen into the combustion cylinder; an intake valve and an exhaust valve, the intake valve is movably arranged in the intake port, and the exhaust valve is linked with the crankshaft and movably arranged in the exhaust port; an intake cam, the intake cam is the above-mentioned intake cam, the intake cam abuts against the intake valve and is linked with the crankshaft to drive the intake valve to open or close the intake port; a valve adjustment member, the valve adjustment member is connected to the exhaust valve to adjust the exhaust valve to close the exhaust port when the crankshaft rotates θ4; wherein, 0°≤θ4≤25°.

[0016] According to the combustion system of the embodiment of the utility model, the exhaust valve is adjusted to close the exhaust port when the crankshaft rotates θ4 by setting a valve adjustment member, thereby delaying the closing time of the exhaust port and closing the exhaust port only when the crankshaft rotates to θ4, thereby reducing the exhaust gas in the combustion cylinder.

[0017] According to some embodiments of the present invention, θ4 is 10°.

[0018] Another object of the present invention is to provide an engine.

[0019] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0020] An engine includes the above combustion system. The advantages of the engine and the combustion system compared with the prior art are the same, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0022] Figure 1 is a side view of the intake cam in the embodiment of the utility model;

[0023] Figure 2 is a schematic diagram of a combustion system in an embodiment of the utility model;

[0024] Figure 3 yes Figure 2 Schematic diagram of the crankshaft after it rotates clockwise for a certain angle;

[0025] Figure 4 It is a schematic diagram comparing the scheme of the embodiment of the utility model with the related technology, wherein the horizontal axis is the rotation angle of the crankshaft, the vertical axis is the movement distance of the valve, F1 represents the intake valve in the related technology, F2 represents the intake valve in the embodiment of the utility model, F3 represents the exhaust valve in the related technology, and F4 represents the exhaust valve in the embodiment of the utility model.

[0026] Reference numerals:

[0027] 100, intake cam; 10, base circle; 20, cam lobe; 21, buffer opening section; 22, working section;

[0028] 23. Buffer closing section; 1000. Combustion system; 300. Piston; 400. Crankshaft; 600. Exhaust valve. DETAILED DESCRIPTION

[0029] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0030] The following will refer to Figure 1-Figure 4 The utility model is described in detail in conjunction with the embodiments.

[0031] like Figure 1 As shown, according to the intake cam 100 of the embodiment of the utility model, the cam profile of the intake cam 100 includes: a base circle 10 and a cam lobe 20, and the two endpoints of the base circle 10 coincide with the two endpoints of the cam lobe 20 respectively, the two endpoints of the cam lobe 20 are respectively an open endpoint and a closed endpoint, the cam lobe 20 includes a buffer opening segment 21, a working segment 22, and a buffer closing segment 23, the buffer opening segment 21 is connected to the open endpoint, the buffer closing segment 23 is connected to the closed endpoint, the working segment 22 is located between the buffer opening segment 21 and the buffer closing segment 23, and the buffer opening segment 21 and the buffer closing segment 23 are both straight line segments.

[0032] Among them, the wrap angle of the buffer opening section 21 is θ1, 7°≤θ1≤10°, the wrap angle of the working section 22 is θ2, 90°≤θ2≤110°, and the wrap angle of the buffer closing section 23 is θ3, 14°≤θ3≤18°.

[0033] It can be understood that the intake cam 100 is a component in an engine, such as a hydrogen engine, which is also provided with a valve. The intake cam 100 cooperates with the valve to drive the valve to move, thereby opening and closing the intake port of the combustion cylinder, so that air enters the combustion cylinder. Among them, the buffer opening section 21, the working section 22 and the buffer closing section 23 are connected to the valve in sequence, the buffer opening section 21 provides preparation for opening the intake port, and the buffer closing section 23 provides preparation for closing the intake port.

[0034] In the related art, a hydrogen engine uses hydrogen as fuel. When the air intake in the hydrogen engine is closed, the mixed gas in the combustion cylinder flows back into the intake duct, causing instability in the next combustion.

[0035] The inventor of the utility model found through a large number of experiments and studies that due to its own performance limitations, the hydrogen injector not only injects hydrogen during the compression stroke, but the injection process of the hydrogen injector is advanced to the intake stroke, resulting in the mixture in the combustion cylinder flowing back to the intake duct when the intake valve is closed.

[0036] The utility model sets the wrap angle θ1 of the buffer opening section 21 in the range of 7° to 10°, the wrap angle θ2 of the working section 22 in the range of 90° to 110°, and the wrap angle θ3 of the buffer closing section 23 in the range of 14° to 18°, wherein the wrap angle θ1 of the buffer opening section 21 is in the range of 7° to 10°, θ1 is smaller, that is, the preparation time for the opening of the air intake port by the buffer opening section 21 is shorter, thereby making the air intake port open earlier, and when the wrap angle of the working section 22 remains unchanged, the air intake port is closed earlier, thereby reducing the probability of the mixture flowing back to the intake duct, making the combustion more stable.

[0037] Reference Figure 4 As shown, F1 becomes F2, and the air intake is closed when the crankshaft 400 rotates to a smaller angle. The utility model adopts a small wrap angle intake cam 100 solution to close the valve earlier at the same intake opening time, thereby reducing the amount of hydrogen flowing back into the intake duct, solving the abnormal combustion caused by hydrogen reflux, and controlling the combustion stability of the hydrogen engine, so that the hydrogen engine can obtain higher thermal efficiency and performance, and ultimately improve the power and economy of the whole vehicle; on the basis of the existing gasoline engine, the utility model only changes the intake cam 100 solution, borrows the existing gasoline engine industry chain, trial production, and production line, and mass-produces engines suitable for hydrogen combustion at the lowest transformation cost.

[0038] For example, the wrap angle θ1 of the buffer opening section 21 is 7°; or, the wrap angle θ1 of the buffer opening section 21 is 7.5°; or, the wrap angle θ1 of the buffer opening section 21 is 8°; or, the wrap angle θ1 of the buffer opening section 21 is 8.5°; or, the wrap angle θ1 of the buffer opening section 21 is 9°; or, the wrap angle θ1 of the buffer opening section 21 is 9.5°; or, the wrap angle θ1 of the buffer opening section 21 is 10°.

[0039] For example, the wrap angle θ2 of the working section 22 is 90°; or, the wrap angle θ2 of the working section 22 is 95°; or, the wrap angle θ2 of the working section 22 is 100°; or, the wrap angle θ2 of the working section 22 is 105°; or, the wrap angle θ2 of the working section 22 is 110°.

[0040] For example, the wrap angle θ3 of the buffer closing segment 23 is 14°; or, the wrap angle θ3 of the buffer closing segment 23 is 15°; the wrap angle θ3 of the buffer closing segment 23 is 16°; the wrap angle θ3 of the buffer closing segment 23 is 17°; the wrap angle θ3 of the buffer closing segment 23 is 18°.

[0041] According to the intake cam 100 of the embodiment of the utility model, the wrap angle θ1 of the buffer opening section 21 is in the range of 7° to 10°, the wrap angle θ2 of the working section 22 is in the range of 90° to 110°, and the wrap angle θ3 of the buffer closing section 23 is in the range of 14° to 18°, wherein the wrap angle θ1 of the buffer opening section 21 is in the range of 7° to 10°, and θ1 is smaller, that is, the preparation time for the opening of the intake port by the buffer opening section 21 is shorter, thereby making the intake port open earlier, and when the wrap angle of the working section 22 remains unchanged, the intake port is closed earlier, thereby reducing the probability of the mixture flowing back to the intake duct, making the combustion more stable.

[0042] In some embodiments, the lift of the buffer opening section 21 is h1, 0mm≤h1≤0.05mm.

[0043] Among them, the cam lift is the distance between the center of the base circle 10 and the point on the cam profile minus the length of the radius of the base circle 10. The lift of the buffer opening section 21 refers to the cam lift of the point on the buffer opening section 21 that is farthest from the center of the base circle 10. Similarly, the buffer closing section 23 and the working section 22 are not repeated here.

[0044] In the above scheme, the lift h1 of the buffer opening section 21 is in the range of 0mm to 0.05mm, and the lift of the buffer opening section 21 is controlled within a certain range, thereby affecting the movement range of the valve, avoiding premature opening of the intake port, and avoiding affecting the compression of the valve seat ring on the valve, thereby increasing the service life of the valve seat ring.

[0045] For example, the lift h1 of the buffer opening section 21 is 0 mm; or, the lift h1 of the buffer opening section 21 is 0.01 mm; or, the lift h1 of the buffer opening section 21 is 0.02 mm; or, the lift h1 of the buffer opening section 21 is 0.03 mm; or, the lift h1 of the buffer opening section 21 is 0.04 mm; or, the lift h1 of the buffer opening section 21 is 0.05 mm.

[0046] In some embodiments, the lift of the buffer closing section 23 is h2, 0mm≤h2≤0.1mm.

[0047] In the above scheme, the lift h2 of the buffer closing section 23 is in the range of 0mm to 0.1mm. The buffer closing section 23 is controlled within a certain range to affect the movement range of the valve during the closing stage of the intake port. The lift of the closing buffer section is small, so that the compression of the valve seat ring is at an appropriate level, avoiding damage to the valve seat ring and making the stability of the entire structure higher.

[0048] For example, the lift h2 of the buffer closing section 23 is 0 mm; or, the lift h2 of the buffer closing section 23 is 0.01 mm; or, the lift h2 of the buffer closing section 23 is 0.02 mm; or, the lift h2 of the buffer closing section 23 is 0.03 mm; or, the lift h2 of the buffer closing section 23 is 0.04 mm; or, the lift h2 of the buffer closing section 23 is 0.05 mm; or, the lift h2 of the buffer closing section 23 is 0.06 mm; or, the lift h2 of the buffer closing section 23 is 0.07 mm; or, the lift h2 of the buffer closing section 23 is 0.08 mm; or, the lift h2 of the buffer closing section 23 is 0.09 mm.

[0049] In some embodiments, the lift of the working section 22 is h3, 3.5 mm ≤ h3 ≤ 4.5 mm.

[0050] In the above scheme, the lift h3 of the working section 22 is in the range of 3.5mm to 4.5mm. The working section 22 is controlled within a certain range, and the intake inertia is fully utilized to improve the restart efficiency, so that the hydrogen engine has the advantages of high specific power and low fuel consumption, which greatly improves the power, economy and reliability.

[0051] For example, the lift h3 of the working section 22 is 3.5 mm; or, the lift h3 of the working section 22 is 3.6 mm; or, the lift h3 of the working section 22 is 3.7 mm; or, the lift h3 of the working section 22 is 3.8 mm; or, the lift h3 of the working section 22 is 3.9 mm; or, the lift h3 of the working section 22 is 4.0 mm; or, the lift h3 of the working section 22 is 4.1 mm; or, the lift h3 of the working section 22 is 4.2 mm; or, the lift h3 of the working section 22 is 4.3 mm; or, the lift h3 of the working section 22 is 4.4 mm; or, the lift h3 of the working section 22 is 4.5 mm.

[0052] In some embodiments, the lift of the working section 22 is 4.13 mm, the lift of the buffer opening section 21 is 0.03 mm, and the lift of the buffer closing section 23 is 0.09 mm.

[0053] In the above scheme, the lift of the working section 22 is set to 4.13mm, the lift of the buffer opening section 21 is set to 0.03mm, and the lift of the buffer closing section 23 is set to 0.09mm. The cam profile is reasonably optimized and designed. The optimized cam profile can control the intake valve to make full use of the intake inertia to improve the charging efficiency, thereby realizing the advantages of high power per liter and low fuel consumption of the engine, so that the overall performance of the intake cam 100 is relatively high.

[0054] Reference Figure 1 As shown, in some embodiments, the radius of the base circle 10 is R, 15.5 mm ≤ R ≤ 17.5 mm.

[0055] In the above scheme, the radius of the base circle 10 is selected within the range of 15.5 mm to 17.5 mm, and the overall wear of the intake cam 100 during operation is in a better condition, which is beneficial to reducing the wear of the intake cam 100 and increasing the service life of the intake cam 100.

[0056] For example, the radius R of the base circle 10 is 15.5 mm; or, the radius R of the base circle 10 is 15.7 mm; or, the radius R of the base circle 10 is 16 mm; or, the radius R of the base circle 10 is 16.2 mm; or, the radius R of the base circle 10 is 16.5 mm; or, the radius R of the base circle 10 is 16.8 mm; or, the radius R of the base circle 10 is 17 mm; or, the radius R of the base circle 10 is 17.2 mm; or, the radius R of the base circle 10 is 17.5 mm.

[0057] In some embodiments, R is 16 mm.

[0058] In the above solution, the radius R of the base circle 10 is set to 16 mm, so that the operation of the hydrogen engine and the wear of the intake cam 100 optimize the structure of the base circle 10, so that the overall performance is improved to a better level.

[0059] Reference Figure 1 As shown, in some embodiments, θ1 is 9.5°, θ2 is 103.5°, and θ3 is 16°.

[0060] In the above scheme, the wrap angle θ1 of the buffer opening section 21 is set to 9.5°, the wrap angle θ2 of the working section 22 is set to 103.5°, and the wrap angle θ3 of the buffer closing section 23 is 16°, so that the intake valve closes the intake port earlier, reducing the probability of the mixture flowing back from the combustion cylinder to the intake duct, and reducing the proportion of hydrogen return in the intake duct from 0.3% to 0%.

[0061] Specifically, taking a hydrogen engine with a speed of 4000 rpm (revolutions per minute) as an example, the hydrogen engine reaches a unit hourly hydrogen consumption of 8.6 kg / h at 230 Nm, while the hydrogen injection rate of the hydrogen injector is 8.0 kg / h, and the required hydrogen injection pulse width is 8.14 ms. In order to reduce the emission of the hydrogen engine, the more uniform the concentration of the mixed gas is, the better the emission effect is. It is necessary to ensure that the hydrogen injection is completed 80° CA before the top dead center, and the start time of the hydrogen injection needs to be 90° CA before the bottom dead center of the intake stroke piston 300. Therefore, in the embodiment of the utility model, the wrap angle θ1 of the buffer opening section 21 is set to 9.5°, and the crankshaft 400 closes the intake port when it rotates 160°. At the same intake start time, the intake valve can be closed in advance, and the hydrogen mixture in the cylinder caused by the upward compression stroke of the engine piston 300 will flow back to the intake duct. The use of a small wrap angle camshaft solution can reduce the proportion of hydrogen back in the intake duct from 0.3% to 0%.

[0062] Reference Figure 2 , Figure 3 As shown, the combustion system 1000 according to the embodiment of the present invention includes: a combustion cylinder, a piston 300, a crankshaft 400, a hydrogen injector, an exhaust valve 600, an intake cam 100 and a valve adjustment member.

[0063] The combustion cylinder has an intake port and an exhaust port. The piston 300 is movably mounted in the combustion cylinder. The crankshaft 400 is connected to the piston 300 to drive the piston 300 to move. A hydrogen injector is provided in the combustion cylinder to inject hydrogen into the combustion cylinder. The intake valve is movably provided at the intake port, and the exhaust valve 600 is movably provided at the exhaust port. The intake cam 100 is the intake cam 100 of the above-mentioned hydrogen engine, and the intake cam 100 abuts against the intake valve and is linked to the crankshaft 400 to drive the intake valve to open or close the intake port. The valve adjustment member is connected to the exhaust valve 600 to adjust the exhaust valve 600 to close the exhaust port when the crankshaft 400 rotates θ4. Among them, 0°≤θ4≤25°.

[0064] It can be understood that the crankshaft 400 and the intake cam 100 in the combustion system 1000 are associated with each other, and the two cooperate to drive the piston 300 and the exhaust valve 600, so that the entry of hydrogen, the entry of air, and the discharge of exhaust gas are at certain moments, thereby realizing the normal operation of the hydrogen engine. Among them, the valve adjustment member can adjust the exhaust valve 600, and change the linkage characteristics of the exhaust valve 600 and the crankshaft 400. After the adjustment of the valve adjustment member, when the crankshaft 400 rotates to θ4, the exhaust valve 600 closes the exhaust port and stops discharging the exhaust gas in the combustion cylinder.

[0065] It should be noted that in the exhaust stroke, the crankshaft 400 rotates, the piston 300 moves from the bottom dead center to the top dead center, the exhaust port is opened, and when the piston 300 is at the top dead center, the angle of the crankshaft 400 is 0°. Figure 4 As shown, F3 becomes F4, and the exhaust port is closed later. Compared with the related art in which the exhaust port is closed when the crankshaft rotates to -5°, the exhaust port closing time is delayed in the utility model, and the exhaust port is closed only when the crankshaft 400 rotates to θ4, so that there is less exhaust gas in the combustion cylinder.

[0066] For example, θ4 is 0°; or, θ4 is 5°; or, θ4 is 10°, the residual exhaust gas rate in the combustion cylinder is reduced from 4.64% to 1.65%; or, θ4 is 15°; or, θ4 is 20°; or, θ4 is 25°.

[0067] According to the combustion system 1000 of the embodiment of the utility model, the exhaust valve 600 is adjusted to close the exhaust port when the crankshaft 400 rotates to θ4 by setting a valve adjustment member, thereby delaying the closing time of the exhaust port. The exhaust port is closed only when the crankshaft 400 rotates to θ4, thereby reducing the exhaust gas in the combustion cylinder.

[0068] Specifically, θ4 is 10°, and the exhaust valve 600 is closed later, so that fresh air can sweep out the residual exhaust gas in the combustion cylinder, thereby reducing the temperature in the combustion cylinder, which can effectively reduce abnormal combustion and improve the performance and fuel consumption of the hydrogen engine.

[0069] Adjust the VVT ​​(variable valve timing), that is, the valve adjustment part, to reduce the residual exhaust gas in the combustion cylinder. Different VVT angles correspond to different amounts of residual exhaust gas. The initial phase intake valve opening time is -5°CA, the exhaust valve 600 closing time is -15°CA, the intake valve opening time remains unchanged, and the exhaust valve 600VVT angle is adjusted to delay the exhaust valve 600 closing time by 25°CA to 10°CA. The residual exhaust gas rate in the engine cylinder is reduced from 4.64% to 1.65%.

[0070] The engine according to the embodiment of the present invention includes the combustion system 1000 mentioned above.

[0071] According to the engine of the embodiment of the utility model, the small wrap angle intake cam 100 shaft scheme is adopted to close the valve earlier at the same intake opening time, thereby reducing the amount of mixed gas flowing back into the intake duct, solving the abnormal combustion caused by the backflow, controlling the combustion stability of the engine, and enabling the engine to obtain higher thermal efficiency and performance, thereby ultimately improving the power and economy of the whole vehicle; on the basis of the existing gasoline engine, the utility model only changes the scheme of the intake cam 100, borrows the industrial chain, trial production, and production line of the existing gasoline engine, and mass-produces engines suitable for hydrogen combustion at the lowest transformation cost; by setting the valve adjustment part, the exhaust valve 600 is adjusted to close the exhaust port when the crankshaft 400 rotates θ4, and the closing time of the exhaust port is delayed. The exhaust port is closed only when the crankshaft 400 rotates to θ4, so that there is less exhaust gas in the combustion cylinder, thereby reducing the temperature in the combustion cylinder, which can effectively reduce abnormal combustion and improve engine performance and fuel consumption.

[0072] Specifically, the engine is configured as a hydrogen engine.

[0073] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An intake cam (100), characterized in that: The cam profile of the intake cam (100) comprises: a base circle (10) and a cam lobe (20), and the two end points of the base circle (10) respectively coincide with the two end points of the cam lobe (20), and the two end points of the cam lobe (20) are respectively an opening end point and a closing end point, and the cam lobe (20) comprises a buffer opening section (21), a working section (22), and a buffer closing section (23), wherein the buffer opening section (21) is connected to the opening end point, and the buffer closing section (23) is connected to the closing end point, and the working section (22) is located between the buffer opening section (21) and the buffer closing section (23), and the buffer opening section (21) and the buffer closing section (23) are both straight line sections; wherein, The wrap angle of the buffer opening section (21) is θ1, 7°≤θ1≤10°, the wrap angle of the working section (22) is θ2, 90°≤θ2≤110°, and the wrap angle of the buffer closing section (23) is θ3, 14°≤θ3≤18°.

2. The intake cam (100) according to claim 1, characterized in that: The lift of the buffer opening section (21) is h1, 0mm≤h1≤0.05mm.

3. The intake cam (100) according to claim 2, characterized in that: The lift of the buffer closing section (23) is h2, 0mm≤h2≤0.1mm.

4. The intake cam (100) according to claim 3, characterized in that: The lift of the working section (22) is h3, 3.5mm≤h3≤4.5mm.

5. The intake cam (100) according to claim 4, characterized in that: The lift of the working section (22) is 4.13 mm, the lift of the buffer opening section (21) is 0.03 mm, and the lift of the buffer closing section (23) is 0.09 mm.

6. The intake cam (100) according to claim 1, characterized in that: The radius of the base circle (10) is R, 15.5 mm ≤ R ≤ 17.5 mm.

7. The intake cam (100) according to claim 1, characterized in that: θ1 is 9.5°, θ2 is 103.5°, and θ3 is 16°.

8. A combustion system (1000), characterized in that: include; A combustion cylinder having an air inlet and an exhaust port; a piston (300), the piston (300) being movably mounted in the combustion cylinder; a crankshaft (400), wherein the crankshaft (400) is connected to the piston (300) to drive the piston (300) to move; A hydrogen injector, the hydrogen injector is arranged in the combustion cylinder to inject hydrogen into the combustion cylinder; An intake valve and an exhaust valve (600), wherein the intake valve is movably disposed at the intake port, and the exhaust valve (600) is linked to the crankshaft (400) and movably disposed at the exhaust port; An intake cam (100), wherein the intake cam (100) is the intake cam (100) according to any one of claims 1 to 7, wherein the intake cam (100) abuts against the intake valve and is linked to the crankshaft (400) to drive the intake valve to open or close the intake port; A valve adjustment member connected to the exhaust valve (600) to adjust the exhaust valve (600) to close the exhaust port when the crankshaft (400) rotates θ4; wherein: 0°≤θ4≤25°.

9. The combustion system (1000) according to claim 8, characterized in that: θ4 is 10°.

10. An engine, characterized in that: A combustion system (1000) comprising the combustion system of claim 8 or 9.

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