CN111156061A

CN111156061A - Engine and engine noise reduction method

Info

Publication number: CN111156061A
Application number: CN201911424260.0A
Authority: CN
Inventors: 张海龙; 陈琳; 于健; 孙荣健
Original assignee: Weichai Power Co Ltd
Current assignee: Weichai Power Co Ltd
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2020-05-15

Abstract

The invention provides an engine and an engine noise reduction method, which relate to the technical field of engines and comprise the following steps: the cylinder cover and the valve actuating mechanism, the valve actuating mechanism includes the camshaft; the cam shaft is provided with at least one driving cam and at least one balance cam, and the cam tip of the driving cam and the cam tip of the balance cam have opposite rotation angles in the radial direction of the cam shaft; and the elastic mechanism is arranged on the cylinder cover and is elastically abutted and assembled with the balance cam. In the technical scheme, the noise reduction process of the engine starts from an excitation source, and the problem of gear knocking noise caused by switching of positive and negative values of the driving torque of the camshaft can be directly solved.

Description

Engine and engine noise reduction method

Technical Field

The invention relates to the technical field of engines, in particular to an engine and an engine noise reduction method.

Background

The camshaft of the engine periodically compresses and releases the valve spring to realize the opening and closing of the valve, thereby completing the ventilation of the engine. The driving torque of the engine camshaft is a torque curve with periodically fluctuating magnitude and direction under the influence of the cam profile of the camshaft, the rigidity of the valve spring, the valve lift and other factors. In the prior art, the periodic fluctuation of the driving torque of the camshaft of the engine can cause the rotation speed of the gear transmission system to suddenly increase or suddenly decrease, thereby causing the gear of the timing gear system to knock, which can deteriorate the noise of the engine.

Disclosure of Invention

The invention aims to provide an engine and an engine noise reduction method, which aim to solve the technical problem of engine noise in the prior art.

The invention provides an engine, comprising:

the valve actuating mechanism comprises a cam shaft; the camshaft is provided with at least one driving cam and at least one balance cam, and the cam point of the driving cam and the cam point of the balance cam have opposite rotation angles in the radial direction of the camshaft;

and the elastic mechanism is arranged on the cylinder cover and is elastically abutted and assembled with the balance cam.

Furthermore, a groove corresponding to the balance cam is formed in the cylinder cover, an elastic seat is elastically assembled in the groove, and the elastic seat is elastically abutted against the balance cam; the groove and the elastic seat form the elastic mechanism.

Furthermore, the elastic mechanism further comprises an elastic piece, one end of the elastic piece is connected with the elastic seat, and the other end of the elastic piece is fixed in the groove.

Furthermore, the elastic part is a spring, the elastic seat is provided with a mounting groove, a mounting column is arranged in the mounting groove, and one end of the spring is sleeved on the mounting column.

Further, the driving cam is composed of an air inlet cam and an air outlet cam; the number of cam tips of the driving cams and the number of cam tips of the balance cams are equal, and each driving cam and each balance cam form a group.

Furthermore, the driving cam and the balance cam are provided with a plurality of groups, and the plurality of groups of driving cams and the plurality of groups of balance cams are uniformly distributed along the axial direction of the cam shaft.

Furthermore, the balance cam is provided with 3 cam noses, and the 3 cam noses are uniformly distributed along the circumferential direction of the balance cam.

Further, the relative rotation angle is between 40 ° and 99 °.

The invention also provides an engine noise reduction method, based on the engine, the method comprises the following steps:

and in the stage that the driving torque of the driving cam is a negative value, the cam tip of the balance cam is elastically abutted with the elastic mechanism on the cylinder cover, so that the driving torque of the driving cam is increased in the stage.

Further, when the driving torque of the driving cam enters a negative value stage, the balance cam synchronously and elastically abuts against the elastic mechanism to increase the driving torque of the driving cam; and/or when the driving torque of the driving cam is in a positive stage, the cam tip of the balance cam is in a stage of releasing the elastic mechanism.

In the above technical solution, at the stage when the driving torque of the driving cam is a negative value, the cam nose of the balance cam and the elastic mechanism form an elastic abutting effect, and the elastic abutting of the cam nose and the elastic mechanism balances the periodic fluctuation of the driving torque of the cam shaft, so as to balance the problem that the gear transmission system is suddenly fast and suddenly slow, and increase the driving torque of the driving cam at the stage, so that the driving torque of the driving cam is reduced or eliminated at the stage when the driving torque of the driving cam is originally a negative value, and finally the reduction or elimination of the engine noise is realized. The noise reduction process of the engine starts from an excitation source, and the problem of gear knocking noise caused by switching of positive and negative values of driving torque of a camshaft can be directly solved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic view of an assembly of a balance cam and a resilient mechanism according to an embodiment of the present invention;

FIG. 2 is a graph of the cyclic variation of camshaft drive torque in the prior art;

FIG. 3 is a graph of the cyclic variation of the drive torque of the balance cam shown in FIG. 1;

fig. 4 is a graph of a single balance cam drive torque versus a single drive cam drive torque positive and negative cycle change provided by one embodiment of the present invention.

Reference numerals:

1. a cylinder cover; 2. an elastic mechanism;

11. a balance cam;

12. a cam nose of the balance cam;

21. a groove; 22. an elastic seat;

23. an elastic member; 24. mounting grooves;

25. and (6) mounting the column.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 1, the present embodiment provides an engine including:

the valve actuating mechanism comprises a cylinder cover 1 and a valve actuating mechanism, wherein the valve actuating mechanism comprises a camshaft; at least one driving cam and at least one balance cam 11 are arranged on the camshaft, and the cam point of the driving cam and the cam point 12 of the balance cam have opposite rotation angles in the radial direction of the camshaft;

and the elastic mechanism 2 is arranged on the cylinder cover 1, and the elastic mechanism 2 is elastically abutted and assembled with the balance cam 11.

The valve train is a mechanism for opening and closing intake and exhaust valves of each cylinder of the engine at regular time according to the working cycle of the engine to realize the exchange of engine air exchange, and a general valve train mainly comprises a camshaft, a rocker arm shaft, a valve spring and the like. The driving torque is the torque required for driving the camshaft to work. The rotation speed fluctuation is an up-down fluctuation of the instantaneous rotation speed with respect to the average value. The noise of the engine is worsened because the periodic fluctuation of the driving torque of the camshaft of the engine can cause the rotation speed of the gear transmission system to suddenly change during the working process of the camshaft of the engine, namely the process of driving the cam to drive the cylinder to move, and further cause the gear of the timing gear system to knock.

In order to improve the noise problem of the engine, the engine is provided with a balance cam 11 matched with a driving cam, and the balance cam 11 can be matched with the driving cam to carry out periodic elastic abutting motion on the driving motion of the cylinder and the elastic mechanism 2 on the cylinder cover 1 in the periodic rotation process of the camshaft. Therefore, at the stage that the driving torque of the driving cam is a negative value, the cam tip 12 of the balance cam and the elastic mechanism 2 form an elastic abutting effect, the driving torque of the shaft of the balance cam 11 is periodically fluctuated by the elastic abutting of the cam tip 12 and the elastic mechanism, and then the problem that the balance gear transmission system is suddenly fast and suddenly slow is solved, the driving torque of the driving cam at the stage is increased, the driving torque of the driving cam is reduced or eliminated at the stage that the driving torque of the driving cam is originally supposed to be the negative value, and finally the reduction or elimination of the engine noise is realized. The noise reduction process of the engine starts from an excitation source, and the problem of gear knocking noise caused by switching of positive and negative values of driving torque of a camshaft can be directly solved.

Specifically, referring first to fig. 2, an in-line six-cylinder overhead camshaft diesel engine is exemplified, and the original drive torque of the camshaft (equivalent to the drive torque of the drive cam of the camshaft) is shown in fig. 2. When the camshaft is moved, the drive torque of the camshaft fluctuates in magnitude and direction in a cycle of a camshaft rotational angle of 60 °. When the rotation angle of the camshaft is between 40 degrees and 66 degrees, the driving torque of the camshaft is a negative value, the valve actuating mechanism pushes the engine to move through the gear, and the non-working surface of the camshaft gear is in contact with the non-working surface of the driving camshaft gear. When the camshaft rotation angle is between 66 degrees and 99 degrees, the driving torque of the camshaft is a positive value, the engine drives the air distribution structure to move through the gear at the moment, the air distribution structure consumes work, and at the moment, the working surface of the camshaft gear is in contact with the working surface of the driving camshaft gear.

Based on the structure and the working process in the prior art, as shown in fig. 3 and 4, the engine can integrate the balance cam 11 matched with the driving cam on the camshaft and the elastic mechanism 2 matched with the balance picture, and through reasonable and adaptive phase, cam profile, spring rigidity and other designs, the cam tip 12 of the balance cam offsets the negative value of the driving torque of the camshaft by utilizing the torque generated by elastic butting of the elastic mechanism 2 at the stage that the driving torque of the camshaft is the negative value, and reduces the positive value of the driving torque of the camshaft, thereby realizing the relatively stable driving torque of the camshaft.

Referring now to fig. 3, the above-described in-line six cylinder overhead camshaft diesel engine is continued as an example, and is also shown in fig. 1. Based on the matching structure of the balance cam 11 and the elastic mechanism 2, different cam profiles of the balance cam 11 can be designed according to the camshaft driving torques of different valve actuating mechanisms, and the different cam profiles can affect the arrangement of the cams in the circumferential direction of the camshaft, and it should be noted that the balance cam 11 in fig. 1 is only illustrated in structure, and is not limited in number and arrangement form. Those skilled in the art can set the noise reduction according to the above design theory, design structure, and method, and the setting is not limited herein.

Optionally, the driving cam is composed of an air inlet cam and an air outlet cam; the number of the cam tips of the driving cams and the number of the cam tips of the balance cams 11 are equal, and each driving cam and each balance cam 11 form a group. The intake cam and the exhaust cam are well known in the art and will not be described in detail herein. It should be noted that the driving cams and the balance cams 11 have multiple sets, and the multiple sets of the driving cams and the balance cams 11 are uniformly arranged along the axial direction of the camshaft. When the camshaft driving torque curve is set, the balance cam 11 and the elastic mechanism 2 can be reversely arranged according to the existing camshaft driving torque curve, opposite driving torques are generated on the same camshaft angle, the negative value part of the camshaft driving torque is offset, and the positive value part of the camshaft driving torque is reduced. The number of cam tips of the balance cams 11 corresponds to the number of areas where the driving cam has negative torque within 360 °, and those skilled in the art can determine the specific number of balance cams according to practical situations, and is not limited herein.

In one embodiment, taking the cam nose 12 of the balance cam on the left side of fig. 1 as an example, the cam nose 12 of the balance cam enters the rising section at 40 ° to 66 ° of the cam shaft rotation angle, and as the cam shaft rotates, the cam nose 12 of the balance cam starts to compress the elastic mechanism 2 from 40 ° of the cam shaft rotation angle, that is, comes into elastic contact with the elastic mechanism 2, and generates a positive driving torque until the rising section is completed when the cam shaft rotation angle reaches 66 °. Then, the camshaft rotation angle enters the descending section at 66 ° to 99 °, and as the camshaft rotates, the cam nose 12 of the balance cam releases the elastic mechanism 2 from the camshaft rotation angle of 66 °, that is, releases the elastic contact with the elastic mechanism 2, and generates a negative driving torque until the camshaft rotation angle reaches 99 ° to complete the descending section.

Meanwhile, the cam nose 12 of the balance cam on the right side and the cam nose on the left side in fig. 1 are arranged symmetrically at 180 ° to each other. Through design matching of cam profiles, spring stiffness, phase and the like, the driving torque variation situation shown in fig. 3 can be obtained. Optionally, the balance cam 11 may also be provided with 3 cam noses, and the 3 cam noses are uniformly distributed along the circumferential direction of the balance cam 11. In this case, all negative torque values in one cycle of the camshaft can be eliminated by arranging three sets of the balance cams 11 and the driving cams at an angle of 60 °, alternatively, when the ignition top dead center position of the diesel engine piston is defined as 0 °, the relative angle is between 40 ° and 99 °, and the rest can be arranged according to the position of the negative torque.

As shown in fig. 4. After eliminating camshaft drive torque negative value, camshaft drive torque is positive value, and the engine passes through gear drive gas distribution structure motion this moment, and the working face of camshaft gear and the working face contact of drive camshaft gear have eliminated the reverse of non-working face and have strikeed. It should be noted that the number of the cam noses may also be designed according to the cam profile of the balance cam 11 to achieve the cancellation of the negative torque, and those skilled in the art may design according to actual situations, which is not limited herein.

Therefore, when the balance cam 11 and the driving cam are matched through a reasonable rotation included angle, a driving torque change situation shown in fig. 4 can be formed in the rotation process of the camshaft, and the change situation shown in fig. 4 is the driving torque change situation after fig. 2 and fig. 3 are combined. Therefore, after the balance cam 11 is reasonably matched with the driving cam, the negative value of the driving torque of the camshaft can be offset, and the positive value of the driving torque of the camshaft is reduced, so that the driving torque of the camshaft is relatively stable.

With continued reference to fig. 1, a groove 21 corresponding to the balance cam 11 is provided on the cylinder head 1, an elastic seat 22 is elastically assembled in the groove 21, and the elastic seat 22 is elastically abutted to the balance cam 11; the recess 21 and the elastic seat 22 constitute the elastic means 2. At this moment, elastic seat 22 is elastically installed in recess 21, can make the motion structure more stable to balanced cam 11 can form the butt with elastic seat 22, and elastic seat 22 can stretch into or stretch out recess 21 because of elasticity, and its adjustment range to driving torque is bigger, and adjustment stability is better. Optionally, the elastic mechanism 2 further includes an elastic member 23, one end of the elastic member 23 is connected to the elastic seat 22, and the other end of the elastic member 23 is fixed in the groove 21.

With reference to fig. 1, the elastic member 23 is a spring, the elastic seat 22 is provided with an installation groove 24, an installation column 25 is arranged in the installation groove 24, and one end of the spring is sleeved on the installation column 25. The assembly structure of spring and erection column 25 can make the assembly more stable between spring and the elastic seat 22, consequently can produce steady, accurate drive torque when balanced cam 11 and elastic seat 22 elasticity butt to with the steady, accurate negative value of eliminating shaft drive torque of this drive torque who produces, reduce camshaft drive torque's positive value, thereby realize the camshaft drive torque relatively steady.

The invention also provides an engine noise reduction method, based on the engine, the method comprises the following steps: in a stage where the driving torque of the driving cam is negative, the cam nose 12 of the balance cam elastically abuts against the elastic mechanism 2 on the cylinder head 1, and the driving torque of the driving cam at this stage is increased. Therefore, the driving torque of the driving cam at the stage is increased by the periodic fluctuation of the driving torque of the shaft of the balance cam 11 which is elastically abutted with the shaft of the balance cam, so that the driving torque of the driving cam at the stage is reduced or eliminated at the stage which is originally supposed to be a negative value, and finally the noise of the engine is reduced or eliminated. For details, reference may be made to the foregoing description, which is not repeated herein.

In one embodiment, when the driving torque of the driving cam enters a negative value phase, the balance cam 11 is synchronously and elastically abutted with the elastic mechanism 2 to increase the driving torque of the driving cam; and/or, when the driving torque of the driving cam is in a positive phase, the cam tip of the balance cam 11 is in a phase of releasing the elastic mechanism 12. Therefore, the cam point 12 of the balance cam can offset the negative value of the driving torque of the camshaft by the torque generated by elastic abutting with the elastic mechanism 2 at the stage that the driving torque of the camshaft is the negative value through the reasonable and adaptive phase, cam profile, spring stiffness and other designs, and the positive value of the driving torque of the camshaft is reduced, so that the relatively stable driving torque of the camshaft is realized.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An engine, comprising:

2. The engine according to claim 1, characterized in that the cylinder cover is provided with a groove corresponding to the balance cam, an elastic seat is elastically assembled in the groove, and the elastic seat is elastically abutted with the balance cam; the groove and the elastic seat form the elastic mechanism.

3. The engine of claim 2, wherein the resilient mechanism further comprises a resilient member, one end of the resilient member is connected to the resilient mount, and the other end of the resilient member is secured within the recess.

4. The engine of claim 3, wherein the elastic member is a spring, the elastic seat is provided with a mounting groove, a mounting column is arranged in the mounting groove, and one end of the spring is sleeved on the mounting column.

5. The engine according to any one of claims 1 to 4, characterized in that the drive cam is constituted by one intake cam and one exhaust cam; the number of cam tips of the driving cams and the number of cam tips of the balance cams are equal, and each driving cam and each balance cam form a group.

6. The engine according to claim 5, characterized in that the driving cams and the balancing cams have a plurality of sets which are evenly arranged in the axial direction of the camshaft.

7. An engine according to any one of claims 1 to 4, characterized in that the balance cam is provided with 3 cam noses, the 3 cam noses being evenly distributed in the circumferential direction of the balance cam.

8. An engine according to claim 7, wherein the relative angle of rotation is between 40 ° and 99 °.

9. An engine noise reduction method, based on the engine of any one of claims 1-8, characterized by the steps of:

10. The engine noise reduction method according to claim 9, characterized in that when the driving torque of the driving cam enters a negative value phase, the balance cam is synchronously elastically abutted with the elastic mechanism to increase the driving torque of the driving cam; and/or when the driving torque of the driving cam is in a positive stage, the cam tip of the balance cam is in a stage of releasing the elastic mechanism.