A variable lift valve train, an engine, and a vehicle

Abstract

The present invention provides a variable lift valve train, an engine, and a vehicle. The variable lift valve train includes: an intake camshaft, on which a plurality of groups of intake cams are provided, and the maximum pitch diameters of at least one group of the plurality of groups of intake cams are not equal to those of at least one other group of intake cams. Among them, the intake cams are used to connect with intake valves; an exhaust camshaft, on which a plurality of groups of exhaust cams are provided, and the maximum pitch diameters of at least one group of the plurality of groups of exhaust cams are not equal to those of at least one other group of exhaust cams. Among them, the exhaust cams are used to connect with exhaust valves. In the present invention, according to the firing intervals between the cylinders of the engine, the maximum pitch diameters of the intake cams and the exhaust cams are adjusted to further adjust the opening sizes of the intake and exhaust valves, so as to ensure the balance of the intake and exhaust volumes of each cylinder and avoid the differences in the intake volume, combustion explosion pressure, air-fuel ratio, etc. of each cylinder caused by uneven intake and exhaust.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and in particular, to a variable lift valve train, an engine, and a vehicle. Background Art

[0002] For a V-type 8-cylinder engine, since its structure is similar to the coupling of two 4-cylinder engines, and generally a V-angle of 90 degrees is adopted. If a flat crankshaft similar to that of an in-line 4-cylinder engine is used, obvious second-order vibration problems will occur. Moreover, the interval of 90 degrees between the two rows of cylinders will cause the superposition of this second-order vibration, making the vibration more obvious. Therefore, in terms of structure, a cross crankshaft is generally used to reduce the second-order vibration frequency and amplitude.

[0003] For a V-type 8-cylinder engine using a cross crankshaft, two pistons in each row of cylinders reach the top dead center at intervals of 90 degrees or 270 degrees, resulting in that no matter how the ignition sequence is arranged, one cylinder in each row will be ignited at intervals of 90 degrees or 270 degrees, leading to relatively serious unevenness of intake and exhaust. Uneven intake will cause differences in intake air volume, combustion explosion pressure, air-fuel ratio, etc. of each cylinder, affecting the consistency of combustion.

[0004] In view of the above problems, no effective solution has been proposed yet. Summary of the Invention

[0005] The main object of the present invention is to provide a variable lift valve train, an engine, and a vehicle to solve the technical problem of poor combustion consistency caused by uneven intake and exhaust air volumes of each cylinder of a V-type 8-cylinder engine using a cross crankshaft.

[0006] To achieve the above object, according to one aspect of the present invention, a variable lift valve train is provided, including: an intake camshaft, on which a plurality of groups of intake cams are provided, and the maximum pitch diameters of at least one group of the plurality of groups of intake cams are not equal to those of at least one other group of intake cams, wherein the intake cams are used to connect with intake valves; an exhaust camshaft, on which a plurality of groups of exhaust cams are provided, and the maximum pitch diameters of at least one group of the plurality of groups of exhaust cams are not equal to those of at least one other group of exhaust cams, wherein the exhaust cams are used to connect with exhaust valves.

[0007] Further, the included angles of at least one group of the plurality of intake cams are not equal to those of at least one other group of intake cams, and the included angles of at least one group of the plurality of exhaust cams are not equal to those of at least one other group of exhaust cams.

[0008] Further, the included angles of the intake cams and the exhaust cams decrease as the maximum pitch diameter decreases and increase as the maximum pitch diameter increases.

[0009] Furthermore, each group of intake cams has two, and the two intake cams in each group are arranged in parallel. Each group of exhaust cams has two, and the two exhaust cams in each group are arranged in parallel.

[0010] Furthermore, the profiles of multiple intake cams with equal maximum radii are all the same, and the profiles of multiple exhaust cams with equal maximum radii are all the same.

[0011] Furthermore, the intake camshaft includes: a first intake camshaft, on which a first intake cam, a second intake cam, a third intake cam, and a fourth intake cam are sequentially arranged; a second intake camshaft, which is arranged in parallel with the first intake camshaft, and on which a fifth intake cam, a sixth intake cam, a seventh intake cam, and an eighth intake cam are sequentially arranged; the maximum radii of the first intake cam and the sixth intake cam are both R1, the maximum radii of the third intake cam and the fifth intake cam are both R2, and the maximum radii of the second intake cam, the fourth intake cam, the seventh intake cam, and the eighth intake cam are all R3, where R1 < R3 < R2.

[0012] Furthermore, the exhaust camshaft includes: a first exhaust camshaft, on which a first exhaust cam, a second exhaust cam, a third exhaust cam, and a fourth exhaust cam are sequentially arranged; a second exhaust camshaft, which is arranged in parallel with the first exhaust camshaft, and on which a fifth exhaust cam, a sixth exhaust cam, a seventh exhaust cam, and an eighth exhaust cam are sequentially arranged; the maximum radii of the first exhaust cam and the sixth exhaust cam are both R4, the maximum radii of the third exhaust cam and the fifth exhaust cam are both R5, and the maximum radii of the second exhaust cam, the fourth exhaust cam, the seventh exhaust cam, and the eighth exhaust cam are all R6, where R4 > R6 > R5.

[0013] Furthermore, it further includes: a phase controller, which is connected to the intake camshaft and the exhaust camshaft; an oil control valve, which is signal-connected to the phase controller, and the oil control valve is used to control the phase controller to drive the intake camshaft and the exhaust camshaft to rotate.

[0014] According to another aspect of the present invention, there is provided an engine, including a variable valve lift mechanism, and the variable valve lift mechanism is the above-mentioned variable valve lift mechanism.

[0015] According to another aspect of the present invention, there is provided a vehicle, including a variable valve lift mechanism, and the variable valve lift mechanism is the above-mentioned variable valve lift mechanism.

[0016] Applying the technical solution of the present invention, at least one group of the multiple intake cams is not equal to the maximum outer diameter of at least one other group of intake cams, and at least one group of the multiple exhaust cams is not equal to the maximum outer diameter of at least one other group of exhaust cams. That is, according to the firing intervals between the cylinders of the engine, the maximum outer diameters of the intake cams and the exhaust cams are adjusted to further regulate the opening sizes of the intake and exhaust valves, so as to ensure the balance of the intake and exhaust volumes of each cylinder and avoid the differences in the intake volume, combustion explosion pressure, air-fuel ratio, etc. of each cylinder caused by uneven intake and exhaust. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0018] Figure 1 The structural schematic diagram of an embodiment of a variable valve lift valve train according to the present invention is shown;

[0019] Figure 2 The sequential schematic diagram of an embodiment of the engine firing interval according to the present invention is shown;

[0020] Figure 3 The linear schematic diagram of the third intake cam and the fifth intake cam in the present invention is shown;

[0021] Figure 4 The schematic diagram of the optimization process of the linear type of the intake and exhaust cams is shown.

[0022] Among them, the above-mentioned accompanying drawings include the following reference numerals:

[0023] 10, the first intake camshaft; 11, the first intake cam; 12, the second intake cam; 13, the third intake cam; 14, the fourth intake cam;

[0024] 20, the second intake camshaft; 21, the fifth intake cam; 22, the sixth intake cam; 23, the seventh intake cam; 24, the eighth intake cam;

[0025] 30, the first exhaust camshaft; 31, the first exhaust cam; 32, the second exhaust cam; 33, the third exhaust cam; 34, the fourth exhaust cam;

[0026] 40, the second exhaust camshaft; 41, the fifth exhaust cam; 42, the sixth exhaust cam; 43, the seventh exhaust cam; 44, the eighth exhaust cam;

[0027] 50, the phase controller;

[0028] 60, the oil control valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0031] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order different from those illustrated or described herein. In addition, the terms "comprise" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0032] Now, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many different forms and should not be construed as being limited only to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of the present application is thorough and complete, and the concept of these exemplary embodiments is fully conveyed to those of ordinary skill in the art. In the drawings, for clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to denote the same devices, and thus their description will be omitted.

[0033] In combination with Figures 1 to 4 As shown, according to a specific embodiment of the present application, a variable lift valve train is provided.

[0034] Specifically, the variable lift valve train includes an intake camshaft and an exhaust camshaft. A plurality of groups of intake cams are provided on the intake camshaft, and the maximum pitch diameter of at least one group of the plurality of groups of intake cams is not equal to that of at least one other group of intake cams. Among them, the intake cams are used to connect with intake valves. A plurality of groups of exhaust cams are provided on the intake camshaft, and the maximum pitch diameter of at least one group of the plurality of groups of exhaust cams is not equal to that of at least one other group of exhaust cams. Among them, the exhaust cams are used to connect with exhaust valves.

[0035] It should be noted that the V-type 8-cylinder engine with a cross crankshaft includes left and right cylinder blocks. The left cylinder block of the engine is sequentially numbered 1-2-3-4, and the right cylinder block of the engine is sequentially numbered 5-6-7-8. Among them, cylinder block No. 1 and cylinder block No. 5 are arranged opposite to each other left and right, cylinder block No. 2 and cylinder block No. 6 are arranged opposite to each other left and right, cylinder block No. 3 and cylinder block No. 7 are arranged opposite to each other left and right, and cylinder block No. 4 and cylinder block No. 8 are arranged opposite to each other left and right. As Figure 2 shown, the firing order of this engine is 1-5-4-8-6-3-7-2. In the left row of the engine, the firing interval between cylinder 2 and cylinder 1 is 90° crankshaft angle, and the firing interval between cylinder 4 and cylinder 3 is 270° crankshaft angle. In the right row of the engine, the firing interval between cylinder 8 and cylinder 6 is 90° crankshaft angle, and the firing interval between cylinder 7 and cylinder 5 is 270° crankshaft angle. The ideal firing interval is 180°. The uneven firing interval will cause uneven intake and exhaust in each of the left and right rows. Among them, uneven intake will cause differences in the intake air volume, combustion explosion pressure, air-fuel ratio, etc. of each cylinder, affecting the cyclic variation of combustion and the combustion consistency. Uneven exhaust will cause strong exhaust interference, affecting the in-cylinder combustion state, and also feedback as poor combustion consistency.

[0036] In the embodiment of the present application, at least one group of the multiple intake cams is not equal to at least one group of the remaining intake cams in the maximum radial dimension, and at least one group of the multiple exhaust cams is not equal to at least one group of the remaining exhaust cams in the maximum radial dimension. That is, according to the firing interval between the cylinder blocks of the engine, the maximum radial dimension of the intake cam and the exhaust cam is adjusted to further adjust the opening size of the intake and exhaust valves to ensure the balance of the intake air volume and the exhaust air volume of each cylinder block, and avoid differences in the intake air volume, combustion explosion pressure, air-fuel ratio, etc. caused by uneven intake and exhaust.

[0037] Furthermore, at least one group of the multiple intake cams is not equal to at least one group of the remaining intake cams in the included angle, and at least one group of the multiple exhaust cams is not equal to at least one group of the remaining exhaust cams in the included angle. By adjusting the included angle of the intake cam and the exhaust cam, the opening size of the intake and exhaust valves is assisted to be adjusted. Among them, the larger the included angle, the longer the intake and exhaust time, and the smaller the included angle, the relatively shorter the intake and exhaust time.

[0038] Among them, the included angle of the intake cam and the exhaust cam decreases as the maximum radial dimension decreases and increases as the maximum radial dimension increases. Specifically, the larger the maximum radial dimension of the intake cam, the larger the opening of the corresponding intake valve. In the same time, the larger the intake air volume, and the included angle increases as the maximum radial dimension increases to control the opening duration of the intake valve to assist in increasing the intake air volume and avoid the weakening of the strength due to the increase of the maximum radial dimension.

[0039] It should be noted that, based on the maximum cylinder block diameter corresponding to a firing interval equal to 180° crankshaft rotation angle, the maximum cylinder block diameter corresponding to a firing interval less than 180° crankshaft rotation angle needs to be increased, and the corresponding included angle increases; the maximum cylinder block diameter corresponding to a firing interval greater than 180° crankshaft rotation angle needs to be decreased, and the corresponding included angle decreases.

[0040] Further, each group of intake cams has two, and the two intake cams in each group are arranged in parallel. Each group of exhaust cams has two, and the two exhaust cams in each group are arranged in parallel. By connecting two intake cams to the intake valves and two exhaust cams to the exhaust valves, the probability that the cams affect the intake and exhaust volumes due to wear is reduced.

[0041] Further, the profiles of multiple intake cams with equal maximum diameters are all the same, and the profiles of multiple exhaust cams with equal maximum diameters are all the same. Designing the profiles of cams with equal maximum diameters to be the same is convenient for unified production and can reduce production costs.

[0042] Specifically, in the embodiment of the present application, the intake camshaft includes a first intake camshaft 10 and a second intake camshaft 20. The first intake camshaft 10 is sequentially provided with a first intake cam 11, a second intake cam 12, a third intake cam 13, and a fourth intake cam 14. The second intake camshaft 20 is arranged in parallel with the first intake camshaft 10. The second intake camshaft 20 is sequentially provided with a fifth intake cam 21, a sixth intake cam 22, a seventh intake cam 23, and an eighth intake cam 24. The maximum diameters of the first intake cam 11 and the sixth intake cam 22 are both R1, the maximum diameters of the third intake cam 13 and the fifth intake cam 21 are both R2, and the maximum diameters of the second intake cam 12, the fourth intake cam 14, the seventh intake cam 23, and the eighth intake cam 24 are all R3, where R1 < R3 < R2.

[0043] It should be noted that the numbering order of the intake cams is consistent with the numbering order of each cylinder block of the engine. The profiles of the second intake cam 12, the fourth intake cam 14, the seventh intake cam 23, and the eighth intake cam 24 are the same, and they are all basic profiles. The profiles of the first intake cam 11 and the sixth intake cam 22 are the same, and they are both non - basic profiles. The profiles of the third intake cam 13 and the fifth intake cam 21 are the same, and they are both non - basic profiles. As Figure 3 shown, curve A is the basic profile, and curve B is the profile of the third intake cam 13 and the fifth intake cam 21.

[0044] Specifically, in the embodiments of the present application, the exhaust camshaft includes a first exhaust camshaft 30 and a second exhaust camshaft 40. The first exhaust camshaft 30 is sequentially provided with a first exhaust cam 31, a second exhaust cam 32, a third exhaust cam 33, and a fourth exhaust cam 34. The second exhaust camshaft 40 is arranged in parallel with the first exhaust camshaft 30. The second exhaust camshaft 40 is sequentially provided with a fifth exhaust cam 41, a sixth exhaust cam 42, a seventh exhaust cam 43, and an eighth exhaust cam 44. The maximum radial diameters of both the first exhaust cam 31 and the sixth exhaust cam 42 are R4. The maximum radial diameters of both the third exhaust cam 33 and the fifth exhaust cam 41 are R5. The maximum radial diameters of the second exhaust cam 32, the fourth exhaust cam 34, the seventh exhaust cam 43, and the eighth exhaust cam 44 are all R6, where R4 > R6 > R5.

[0045] It should be noted that the numbering sequence of the exhaust cams is consistent with the numbering sequence of each cylinder block of the engine. The profiles of the second exhaust cam 32, the fourth exhaust cam 34, the seventh exhaust cam 43, and the eighth exhaust cam 44 are the same, all being the basic profile. The profiles of the first exhaust cam 31 and the sixth exhaust cam 42 are the same, both being non-basic profiles. The profiles of the third exhaust cam 33 and the fifth exhaust cam 41 are the same, both being non-basic profiles.

[0046] First, select the basic profile through simulation, calibrate the basic test bench data based on this profile, then perform calibration optimization for the optimized profile, and finally obtain the final calibration data and the locked cam profile. Specifically, the process for determining the cam profile is as Figure 4 shown.

[0047] Furthermore, the variable valve lift mechanism further includes: a phase controller 50 and an oil control valve 60. The phase controller 50 is connected to the intake camshaft and the exhaust camshaft. The oil control valve 60 is signal-connected to the phase controller 50. The oil control valve 60 is used to control the phase controller 50 to drive the intake camshaft and the exhaust camshaft to rotate.

[0048] According to another specific embodiment of the present invention, an engine is provided, including a variable valve lift mechanism, and the variable valve lift mechanism is the variable valve lift mechanism in the above embodiment.

[0049] According to another specific embodiment of the present invention, a vehicle is provided, including a variable valve lift mechanism, and the variable valve lift mechanism is the variable valve lift mechanism in the above embodiment.

[0050] For ease of description, spatial relative terms, such as "above", "over", "on the upper surface", "upper", etc., may be used herein to describe the spatial positional relationship of one device or feature to other devices or features as shown in the figures. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, a device described as "above" or "over" other devices or structures will then be positioned "below" or "under" the other devices or structures. Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations of the spatial relative descriptions used herein will be made.

[0051] In addition to the above, it should also be noted that the "one embodiment", "another embodiment", "embodiment", etc. mentioned in this specification refer to the specific features, structures or characteristics described in connection with that embodiment being included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when describing a specific feature, structure or characteristic in connection with any one embodiment, it is intended that the implementation of such feature, structure or characteristic in combination with other embodiments also falls within the scope of the present invention.

[0052] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0053] The foregoing is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A variable lift valve train, characterized in that, comprising: An intake camshaft, on which multiple groups of intake cams are provided, and the maximum pitch diameters of at least one group among the multiple groups of intake cams are not equal to those of at least one group of the remaining intake cams. Among them, the intake cams are used to connect with intake valves; An exhaust camshaft, on which multiple groups of exhaust cams are provided, and the maximum pitch diameters of at least one group among the multiple groups of exhaust cams are not equal to those of at least one group of the remaining exhaust cams. Among them, the exhaust cams are used to connect with exhaust valves; The intake camshaft includes: A first intake camshaft (10), on which a first intake cam (11), a second intake cam (12), a third intake cam (13), and a fourth intake cam (14) are sequentially arranged; A second intake camshaft (20), which is arranged in parallel with the first intake camshaft (10), and a fifth intake cam (21), a sixth intake cam (22), a seventh intake cam (23), and an eighth intake cam (24) are sequentially arranged on the second intake camshaft (20); The maximum pitch diameters of the first intake cam (11) and the sixth intake cam (22) are both R1, the maximum pitch diameters of the third intake cam (13) and the fifth intake cam (21) are both R2, and the maximum pitch diameters of the second intake cam (12), the fourth intake cam (14), the seventh intake cam (23), and the eighth intake cam (24) are all R3, where R1 < R3 < R2.

2. The variable lift valve train according to claim 1, characterized in that, The included angle of at least one group among the multiple intake cams is not equal to that of at least one group of the remaining intake cams, and the included angle of at least one group among the multiple exhaust cams is not equal to that of at least one group of the remaining exhaust cams.

3. The variable lift valve train according to claim 2, characterized in that, The included angle of the intake cam and the exhaust cam decreases as the maximum pitch diameter decreases and increases as the maximum pitch diameter increases.

4. The variable lift valve train according to claim 1, characterized in that, Each group of intake cams has two, and the two intake cams in each group are arranged in parallel. Each group of exhaust cams has two, and the two exhaust cams in each group are arranged in parallel.

5. The variable lift valve train according to claim 1, characterized in that, The profiles of the multiple intake cams with equal maximum pitch diameters are all the same, and the profiles of the multiple exhaust cams with equal maximum pitch diameters are all the same.

6. The variable lift valve train according to claim 1, characterized in that, The exhaust camshaft includes: A first exhaust camshaft (30), on which a first exhaust cam (31), a second exhaust cam (32), a third exhaust cam (33), and a fourth exhaust cam (34) are sequentially arranged; A second exhaust camshaft (40), the second exhaust camshaft (40) being arranged in parallel with the first exhaust camshaft (30), and a fifth exhaust cam (41), a sixth exhaust cam (42), a seventh exhaust cam (43) and an eighth exhaust cam (44) being sequentially arranged on the second exhaust camshaft (40); The maximum radial diameters of the first exhaust cam (31) and the sixth exhaust cam (42) are both R4, the maximum radial diameters of the third exhaust cam (33) and the fifth exhaust cam (41) are both R5, and the maximum radial diameters of the second exhaust cam (32), the fourth exhaust cam (34), the seventh exhaust cam (43) and the eighth exhaust cam (44) are both R6, wherein R4 > R6 > R5.

7. The variable valve lift valve train according to claim 1, characterized in that, further comprising: A phase controller (50), the phase controller (50) being connected to the intake camshaft and the exhaust camshaft; An oil control valve (60), the oil control valve (60) being signal-connected to the phase controller (50), and the oil control valve (60) being configured to control the phase controller (50) to drive the intake camshaft and the exhaust camshaft to rotate.

8. An engine, comprising a variable valve lift valve train, characterized in that, the variable valve lift valve train is the variable valve lift valve train according to any one of claims 1-7.

9. A vehicle, comprising a variable valve lift valve train, characterized in that, the variable valve lift valve train is the variable valve lift valve train according to any one of claims 1-7.

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