Intake camshaft, engine and vehicle

Abstract

An intake camshaft, an engine and a vehicle. The intake camshaft comprises: a shaft body (1); and at least one cam group (2), the cam group (2) comprising a first cam (201) and a second cam (202), the first cam (201) and the second cam (202) both being sleeved on the shaft body (1) and fixedly connected to the shaft body (1), and the profile of the first cam (201) and the profile of the second cam (202) being different.

Description

Intake camshaft, engine and vehicle

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on January 2, 2024, with application number 202420013493.1 and invention name “Intake camshaft, engine and vehicle”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of vehicle equipment, and in particular to an intake camshaft, an engine and a vehicle. Background Art

[0003] With the increasing demand for engine thermal efficiency, combustion chamber designs are increasingly employing a swirl-tumble coupling mechanism. This means that intake flows between different intake ports connected to the same cylinder need to be asymmetrical, both in duration and volume. Commonly used designs include asymmetric port design and the addition of throttle valves in the intake manifold. However, asymmetric port design prevents precise control of design parameters, while the addition of throttle valves in the intake manifold is costly. Summary of the Invention

[0004] In view of this, the present application provides an intake camshaft, an engine and a vehicle to solve the above technical problems.

[0005] The intake camshaft provided in the present application includes: a shaft body; at least one cam group, the cam group includes a first cam and a second cam, the first cam and the second cam are both sleeved on the shaft body and fixedly connected to the shaft body; the first cam and the second cam have different profiles.

[0006] Optionally, the lift of the first cam is different from the lift of the second cam, and the wrap angle of the first cam is different from the wrap angle of the second cam.

[0007] Optionally, the lift of the first cam is greater than the lift of the second cam, and the wrap angle of the first cam is greater than the wrap angle of the second cam.

[0008] Optionally, the difference between the lift of the first cam and the lift of the second cam is less than 3 mm.

[0009] Optionally, the first cam includes a first base circle and a first convex portion connected to one side of the first base circle, the first cam is provided with a first through hole through the center of the first base circle, the second cam includes a second base circle and a second convex portion connected to one side of the second base circle, the second cam is provided with a second through hole through the center of the second base circle, and the inner walls of the first through hole and the second through hole are matched with the outer wall of the shaft body.

[0010] Optionally, the angle between the projections of a line between the vertex of the first convex portion and the center of the first base circle and a line between the vertex of the second convex portion and the center of the second base circle on a plane perpendicular to the extension direction of the shaft is less than 30°.

[0011] Optionally, the shaft body includes a first end and a second end arranged opposite to each other along its axial direction; the first cam and the second cam are both arranged in a position close to the first end, wherein the first cam is located between the first end and the second cam; and / or the first cam and the second cam are both arranged in a position close to the second end, wherein the first cam is located between the second end and the second cam.

[0012] Optionally, the shaft body includes a weight-reducing hole extending along its length direction.

[0013] Optionally, the intake camshaft further includes: a front end member, which is sleeved on the first end of the shaft body and fixedly connected to the shaft body for driving connection with an external driving member.

[0014] Optionally, the intake camshaft further includes: a signal wheel, which is sleeved on the shaft body and fixedly connected to the shaft body.

[0015] Optionally, the intake camshaft further includes: an oil pump cam, which is sleeved on the second end of the shaft body and fixedly connected to the shaft body for driving the fuel pump.

[0016] Optionally, a reference hole is provided on the shaft body.

[0017] The present application also provides an engine, comprising any of the intake camshafts described above.

[0018] The present application also provides a vehicle comprising the engine described above.

[0019] Compared with the prior art, the above technical solutions provided by this application have at least the following beneficial effects:

[0020] The intake camshaft, engine and vehicle of the present application are used, and by setting the cams corresponding to the same cylinder on the shaft body to have different profiles, such as the first cam and the second cam with different lifts and wrap angles, the two cams cooperate with each other to make the openings of different valves in the same cylinder different, the opening timings are different, and the effective opening time is different, thereby adjusting the intake duration and intake amount entering the same cylinder through different intake ducts corresponding to the first cam and the second cam, realizing asymmetric intake of different intake ducts connected to the same cylinder, generating the vortex-tumble coupling organizational form required by the design in the combustion chamber, improving the thermal efficiency of the engine, and by adjusting the specific lifts and wrap angles of different cams, precise control of the asymmetric requirements of the intake in the same cylinder can be achieved at a low cost.

[0021] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] FIG1 is a schematic diagram of an intake camshaft according to an embodiment of the present application;

[0024] FIG2 is a schematic diagram of a first cam of the intake camshaft shown in FIG1 ;

[0025] FIG3 is a schematic diagram of a second cam of the intake camshaft shown in FIG1 ;

[0026] FIG4 is a schematic diagram of the working state of the intake camshaft shown in FIG1 ;

[0027] Figure 5 is a schematic diagram of the cam profile.

[0028] Figure markings: 1: shaft; 2: cam group; 201: first cam; 2011: first base circle; 2012: first convex portion; 2013: first through hole; 202: second cam; 2021: second base circle; 2022: second convex portion; 2023: second through hole; 3: weight-reducing hole; 4: front end piece; 5: signal wheel; 501: positioning tooth; 6: oil pump cam; 7: reference hole; 8: rocker arm; 9: tappet; 10: valve. Specific embodiments

[0029] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0030] The directional terms such as up, down, left, right, front, back, front, back, top, and bottom mentioned or possibly mentioned in this specification are defined relative to the structure shown in the drawings. They are relative concepts and may vary depending on the location and usage of the device. Therefore, these or other directional terms should not be interpreted as restrictive.

[0031] Figure 1 is a schematic diagram of the intake camshaft described in an embodiment of the present application; Figure 2 is a schematic diagram of the first cam of the intake camshaft shown in Figure 1; Figure 3 is a schematic diagram of the second cam of the intake camshaft shown in Figure 1; Figure 4 is a schematic diagram of the working state of the intake camshaft shown in Figure 1; Figure 5 is a schematic diagram of the cam profile.

[0032] As shown in Figures 1 to 5, the intake camshaft includes a shaft body 1 and at least one cam group 2. The cam group 2 includes a first cam 201 and a second cam 202. The first cam 201 includes a first base circle 2011 and a first convex portion 2012 connected to one side of the first base circle 2011. The first cam 201 has a first through hole 2013 extending through the center of the first base circle 2011. The second cam 202 includes a second base circle 2021 and a second convex portion 2022 connected to one side of the second base circle 2021. The second cam 202 has a second through hole 2023 extending through the center of the second base circle 2021. The first cam 201 and the second cam 202 are both sleeved on the shaft body 1 and fixedly connected to the shaft body 1. The first cam 201 and the second cam 202 have different profiles. Specifically, the lift of the first cam 201 is greater than that of the second cam 202, and the wrap angle of the first cam 201 is greater than that of the second cam 202.

[0033] The valve 10 includes a connected stem and a head, wherein the stem is located in the air passage and the head is located in the combustion chamber. When the valve 10 is not pressed, the head covers the air passage. A cylinder may include multiple valves 10. As shown in FIG4 , during the process of the shaft 1 driving the cam to rotate, the outer edge of the cam always contacts the rocker arm 8. The left end of the rocker arm 8 is rotatably connected to the tappet 9, and the right end is connected to the stem of the valve 10. When the base circle of the cam contacts the rocker arm 8, the rocker arm 8 does not rotate relative to the tappet 9, nor does it press downward on the stem of the valve 10. When the cam's convex portion contacts the rocker arm 8, the rocker arm 8 rotates downward relative to the tappet 9 and presses the stem of the valve 10. The head of the valve 10 is then pressed downward, releasing part of the air passage, and air enters the combustion chamber through the air passage. The greater the distance the valve 10 is pressed downward, the larger the cross-section of the air passage released by the head of the valve 10, that is, the greater the opening of the valve 10. Cam lift controls the opening of valve 10 in the valve train, i.e., the maximum distance valve 10 opens, or the distance between the cam's apex and the base circle's circumferential profile in Figures 2 and 3. The greater the cam lift, the greater the opening of valve 10. Cam wrap angle controls the duration of valve 10 opening in the valve train, i.e., the angle over which valve 10 remains open greater than 1 mm during one rotation of shaft 1. This refers to the duration of valve 10's effective opening. The greater the cam wrap angle, the longer valve 10 remains open. In the present application, two valves 10 are provided in the same cylinder, corresponding to the first cam 201 and the second cam 202 respectively. The lift and the wrap angle of the first cam 201 are both greater than those of the second cam 202. Then, during one rotation of the shaft 1, the opening of the valve corresponding to the first cam 201 is greater than the opening of the valve corresponding to the second cam 202, and the effective opening time of the valve corresponding to the first cam 201 is greater than the effective opening time of the valve corresponding to the second cam 202, thereby adjusting the intake duration and intake amount entering the same cylinder through different intake ducts corresponding to the first cam 201 and the second cam 202.

[0034] By adopting the intake camshaft of the present application, by setting the cams corresponding to the same cylinder on the shaft body 1 to have different profiles, such as the first cam 201 and the second cam 202 with different lifts and wrap angles, the two are coordinated to make the openings of different valves 10 in the same cylinder different, the opening timings are different, and the effective opening times are different, thereby adjusting the intake duration and intake amount entering the same cylinder through different intake ducts corresponding to the first cam 201 and the second cam 202, realizing asymmetric intake of different intake ducts connected to the same cylinder, generating the vortex-tumble coupling organizational form required by the design in the combustion chamber, improving the thermal efficiency of the engine, and by adjusting the specific lifts and wrap angles of different cams, precise control of the asymmetric requirements of the intake in the same cylinder can be achieved at a low cost.

[0035] In this embodiment, as shown in FIG1 , a total of four cam groups 2 are provided on the shaft body 1, that is, the intake camshaft corresponds to four cylinders. Each cam group 2 includes a first cam 201 and a second cam 202 with different lifts and wrap angles, that is, each cylinder is provided with two intake valves 10. The installation angles of different cam groups 2 with respect to the shaft body 1 are different. As shown in FIG2 and FIG3 , the lift of the first cam 201 is H and the wrap angle is α, the lift of the second cam 202 is h and the wrap angle is β, the radius of the first base circle 2011 is equal to the radius of the second base circle 2021, and H>h, α>β. According to existing process parameters, the maximum wrap angle is set to 120° and the minimum is set to 60°. The inner walls of the first through hole 2013 and the second through hole 2023 match the outer wall of the shaft body 1. The first cam 201, the second cam 202, and the shaft body 1 can be fixedly connected by integral molding, interference fit, sintering, or welding. The specific lift and wrap angle of the first cam 201 and the second cam 202 can be adjusted to match the actual application, as long as asymmetric intake of different intake ports connected to the same cylinder can be achieved and a swirl-tumble coupled airflow composition can be formed in the combustion chamber.

[0036] Optionally, the shaft body 1 includes a first end and a second end that are arranged opposite to each other along its axial direction, the first end of the shaft body 1 is mounted with a front end member 4, and the second end of the shaft body 1 is mounted with an oil pump cam 6. The first cam 201 and the second cam 202 in different cam groups 2 corresponding to different cylinders can be arranged in a uniform relative position, for example, the first cam 201 in each cam group 2 faces the first end of the shaft body 1, and the second cam 202 faces the second end of the shaft body 1, that is, the first cam 201 in each cam group 2 is arranged close to the first end of the shaft body 1, and the second cam 202 in each cam group 2 is arranged close to the second end of the shaft body 1; the relative positions of the first cam 201 and the second cam 202 can also be swapped, for example, the first cam 201 in the cam group 2 corresponding to the first cylinder faces the first end of the shaft body 1, and the second cam 20 2 toward the second end of the shaft body 1, which is equivalent to the first cam 201 and the second cam 202 being both sleeved at a position close to the first end of the shaft body 1, wherein the first cam 201 is located closer to the first end, that is, the first cam 201 is located between the first end and the second cam 202; the first cam 201 in the cam group 2 corresponding to the second cylinder faces the second end of the shaft body 1, and the second cam 202 faces the first end of the shaft body 1, which is equivalent to the first cam 201 and the second cam 202 being both sleeved at a position close to the second end of the shaft body 2, wherein the first cam 201 is located closer to the second end, that is, the first cam 201 is located between the second end and the second cam 202.

[0037] As shown in Figure 5 , the abscissa represents the cam's rotation angle, and the ordinate represents the distance between the base circle profile and the point where the cam's outer edge contacts the rocker arm 8, i.e., the distance traveled at the point where the rocker arm 8 contacts the cam in Figure 4 . The maximum distance represents the cam's lift. The upper curve a corresponds to the profile of the first cam 201, and the lower curve b corresponds to the profile of the second cam 202. The figure clearly shows that the lift H of the first cam 201 is greater than the lift h of the second cam 202, with the lift difference between the two being less than 3 mm. Furthermore, the wrap angle α of the first cam 201 is greater than the wrap angle β of the second cam 202. As can be seen from Figure 4, the contact position between the valve 10 and the rocker arm 8 is farther away from the tappet 9 around which the valve 10 rotates than the contact position between the cam and the rocker arm 8. Therefore, when the valve 10 is pressed down and moves 1 mm, that is, when the opening of the valve 10 is 1 mm, the distance moved by the contact position between the rocker arm 8 and the cam is less than 1 mm. Therefore, within the range indicated by the wrap angle in Figure 5, the vertical coordinates corresponding to some curves are less than 1 mm.

[0038] Optionally, the difference between the lift of the first cam 201 and the lift of the second cam 202 is less than 3 mm. This configuration is primarily limited by the structure of the entire valve train. As shown in Figure 4, the tappet 9 is stationary. The rotation of the cam drives the rocker arm 8 to rotate around the ball of the tappet 9, thereby driving the linear motion of the valve 10. This causes contact surface slip between the valve 10 and the rocker arm 8. This slip distance needs to be less than half the diameter of the valve 10, i.e., 2.5-3 mm. Otherwise, excessive slippage can lead to contact surface wear and failure, shortening service life. The greater the cam lift, the greater the slip distance between the valve 10 and the rocker arm 8. The entire valve train design must accommodate the design of cams of varying lift. If the lift differences between different cams corresponding to the same cylinder are too large, a high-lift cam driving the rocker arm 8 will cause excessive slippage between the valve 10, resulting in severe wear and shortening service life. Based on design experience, the lift difference between two cams corresponding to the same cylinder generally does not exceed 3 mm, and the valve train design can accommodate this.

[0039] Optionally, the angle between the projections of a line connecting the vertex of the first convex portion 2012 and the center of the first base circle 2011 and a line connecting the vertex of the second convex portion 2022 and the center of the second base circle 2021 on a plane perpendicular to the extension direction of the shaft 1 is less than 30°. This arrangement improves the coupling effect of the vortex and tumble flow in the combustion chamber.

[0040] In this embodiment, the angle between the projections of the line between the vertex of the first protrusion 2012 and the center of the first base circle 2011, and the line between the vertex of the second protrusion 2022 and the center of the second base circle 2021 on the plane perpendicular to the extension direction of the shaft 1 is 25°, which can also be adjusted according to actual needs.

[0041] Optionally, the shaft body 1 includes a weight-reducing hole 3 extending along its length. This arrangement is beneficial for reducing the overall weight of the intake camshaft, thereby reducing the overall weight of the engine.

[0042] As shown in Figure 1, in this embodiment, the shaft body 1 is provided with a weight-reducing hole 3 along its length. According to actual needs, the weight-reducing hole 3 may not penetrate the shaft body 1, but may extend a certain distance along the shaft body 1.

[0043] Optionally, the intake camshaft further includes a front end member 4, which is sleeved around the first end of the shaft body 1 and fixedly connected to the shaft body 1 for driving connection with an external driver. This arrangement facilitates connection with the external driver via the front end member 4. Driven by the external driver, the front end member 4 and the shaft body 1 rotate, thereby driving the first cam 201 and the second cam 202 connected to the shaft body 1 to rotate synchronously.

[0044] In this embodiment, as shown in Figure 1, the front end member 4 is sleeved on the leftmost end of the shaft body 1 and can be connected to the shaft body 1 by integral molding, interference fit, sintering or welding. The front end member 4 can be a commercially available component that matches the shaft body 1.

[0045] Optionally, the intake camshaft further includes a signal wheel 5, which is sleeved on the shaft body 1 and fixedly connected to the shaft body 1. The signal wheel 5 can provide a signal to an external speed sensor to determine the rotational position of the shaft body 1.

[0046] In this embodiment, as shown in Figure 1, the signal wheel 5 is mounted near the right end of the shaft 1. Four cam groups 2 are mounted between the front end member 4 and the signal wheel 5. The signal wheel 5 has a plurality of positioning teeth 501 of varying sizes arranged irregularly around its circumference. An external speed sensor determines the rotational position of the shaft 1 by monitoring the positions of the various positioning teeth 501. The method for cooperating between the signal wheel 5 and the external speed sensor to monitor the rotational position of the shaft 1 is conventional, and its specific structure and signal transmission principle are not detailed here.

[0047] Optionally, the intake camshaft further includes an oil pump cam 6, which is sleeved on the second end of the shaft body 1 and fixedly connected to the shaft body 1 for driving the fuel pump. The oil pump cam 6 is connected to the fuel pump via a connector to drive the fuel pump.

[0048] In this embodiment, as shown in FIG1 , the oil pump cam 6 is sleeved on the shaft 1 near the right end. The specific specifications and parameters of the oil pump cam 6 can be adjusted according to the working requirements of the fuel pump driven by the oil pump cam 6 .

[0049] Optionally, a reference hole 7 is formed on the shaft body 1. Providing the reference hole 7 allows accurate calculation of the rotation angle of each component relative to the reference hole 7 when the cam group 2 and other components are mounted on the shaft body 1, thereby accurately positioning the relative angular relationship between the components.

[0050] In this embodiment, as shown in FIG. 1 , the reference hole 7 is opened at the left end of the shaft 1 , and the four cam groups 2 are rotated at different angles relative to the reference hole 7 .

[0051] The present application also provides an engine, comprising the intake camshaft described in any of the above embodiments.

[0052] The engine of the present application is configured such that the cams corresponding to the same cylinder on the shaft 1 are configured as first cams 201 and second cams 202 having different lifts and wrap angles. By means of the cooperation between the first and second cams, the opening degrees, opening timings, and effective opening durations of different valves 10 in the same cylinder are different. This adjusts the duration and amount of intake air entering the same cylinder through the different intake passages corresponding to the first and second cams 201 and 202, achieving asymmetric intake of different intake passages connected to the same cylinder. This creates the desired vortex-tumble coupling structure in the combustion chamber, improving the engine's thermal efficiency. Furthermore, by adjusting the specific lifts and wrap angles of the different cams, precise control of the asymmetric intake requirements within the same cylinder can be achieved at a relatively low cost. The engine of the present application may be a range-extended engine.

[0053] The present application also provides a vehicle comprising the engine described above.

[0054] With the vehicle of the present application, by setting the cams corresponding to the same cylinder on the shaft 1 to the first cam 201 and the second cam 202 with different lifts and wrap angles, the two cooperate to make the openings of different valves 10 in the same cylinder different, the opening timings are different, and the effective opening times are different, thereby adjusting the intake duration and intake amount entering the same cylinder through different intake ducts corresponding to the first cam 201 and the second cam 202, realizing asymmetric intake of different intake ducts connected to the same cylinder, generating the vortex-tumble coupling organizational form required by the design in the combustion chamber, improving the thermal efficiency of the engine, and by adjusting the specific lifts and wrap angles of different cams, precise control of the asymmetric requirements of the intake in the same cylinder can be achieved at a low cost.

[0055] As needed, the above technical solutions can be combined to achieve the best technical effect.

[0056] The above are only the principles and preferred embodiments of the present application. It should be noted that, for those skilled in the art, on the basis of the principles of the present application, several other modifications can be made, which should also be considered as the scope of protection of the present application.

Claims

1. An intake camshaft, characterized in that, Comprising: Shaft body; At least one cam group, the cam group includes a first cam and a second cam, both the first cam and the second cam are sleeved on the shaft body and fixedly connected to the shaft body; The profiles of the first cam and the second cam are different.

2. The intake camshaft according to claim 1, wherein: The lift of the first cam is different from the lift of the second cam, and the included angle of the first cam is different from the included angle of the second cam.

3. The intake camshaft according to claim 1, characterized in that: The lift of the first cam is greater than the lift of the second cam, and the included angle of the first cam is greater than the included angle of the second cam.

4. The intake camshaft according to claim 3, wherein: The difference between the lift of the first cam and the lift of the second cam is less than 3 mm.

5. The intake camshaft according to claim 1, characterized in that: The first cam includes a first base circle and a first convex portion connected to one side of the first base circle. The first cam is provided with a first through hole penetrating the center of the first base circle. The second cam includes a second base circle and a second convex portion connected to one side of the second base circle. The second cam is provided with a second through hole penetrating the center of the second base circle. The inner walls of the first through hole and the second through hole are both matched with the outer wall of the shaft body.

6. The intake camshaft according to claim 5, wherein: The included angle between the projection on a plane perpendicular to the extending direction of the shaft body of the line connecting the vertex of the first convex portion and the center of the first base circle and the projection on a plane perpendicular to the extending direction of the shaft body of the line connecting the vertex of the second convex portion and the center of the second base circle is less than 30°.

7. The intake camshaft according to claim 3, wherein The shaft body includes a first end and a second end arranged oppositely along its axial direction; Both the first cam and the second cam are sleeved on the part close to the first end, wherein the first cam is located between the first end and the second cam; And / or, both the first cam and the second cam are sleeved on the part close to the second end, wherein the first cam is located between the second end and the second cam.

8. The intake camshaft according to any one of claims 1-7, wherein: The shaft body includes a weight-reducing hole extending along its own length direction.

9. The intake camshaft according to any one of claims 1-7, characterized in that, Further comprising: A front end member, the front end member is sleeved on the first end of the shaft body and fixedly connected to the shaft body for driving connection with an external driving member.

10. The intake camshaft according to any one of claims 1-7, characterized in that, Further comprising: A signal wheel, the signal wheel is sleeved on the shaft body and fixedly connected to the shaft body.

11. The intake camshaft according to any one of claims 1-7, characterized in that, Further comprising: An oil pump cam, the oil pump cam is sleeved on the second end of the shaft body and fixedly connected to the shaft body for driving an oil pump.

12. The intake camshaft according to any one of claims 1-7, characterized in that: A reference hole is provided on the shaft body.

13. An engine, characterized in that, Comprising the intake camshaft according to any one of claims 1-12.

14. A vehicle, characterized in that, Comprising the engine according to claim 13.

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