Engine valve driving mechanism capable of generating two kinds of valve motion

Abstract

According to the engine valve driving mechanism capable of generating two kinds of valve movement, the outline of a newly-added auxiliary cam is partially or completely larger than the outline of a conventional engine cam, a connecting mechanism is arranged between an auxiliary rocker arm and a conventional engine rocker arm, and the auxiliary rocker arm and the conventional engine rocker arm are disconnected at a disconnection station of the connecting mechanism; only conventional valve movement of the engine is generated; at the communicating station of the connecting mechanism, the auxiliary rocker arm is connected with a conventional rocker arm of the engine through the connecting mechanism, movement generated by the part, larger than the conventional cam contour of the engine, of the auxiliary cam contour is transmitted to an air valve of the engine, and auxiliary air valve movement of the engine is formed independently or in combination with conventional air valve movement. The auxiliary valve motion includes a miller cycle with a delayed closing to reduce the compression ratio and fuel consumption of the engine.

Description

Technical Field

[0001] The utility model relates to the field of machinery, in particular to the field of engine valve driving, in particular to an engine valve driving mechanism which generates two valve movements. Background Art

[0002] Conventional valve actuation in vehicle engines is well known in the art, having been used for over a century. Conventional valve actuation utilizes conventional valve actuators (including rocker arms) to control the movement of the engine valves for conventional ignition operation. However, due to additional demands for engine fuel efficiency, exhaust emissions, and engine braking, an increasing number of engines are adopting various forms of variable valve actuation, including the two-stage variable valve actuation widely used in passenger cars, such as the VTEC (Very High-Performance Control) engine in Honda, Japan.

[0003] Chinese utility model patent CN104411925B (2018) discloses a system, method, and apparatus for controlling variable valve operation in an automotive engine. Two cams have different lift profiles. Inner and outer arms are positioned beneath the cams, and a latch locks the inner and outer arms together, transmitting the different cam lift profiles to the engine valves. This utility model utilizes overhead cams acting on rollers located in the center of the inner and outer arms. Its application is limited to passenger cars and is not suitable for commercial vehicles. Utility Model Content

[0004] The purpose of the utility model is to provide an engine valve drive mechanism that generates two valve movements, to solve the problem that commercial vehicles in the prior art cannot adopt the variable valve drive mechanism of passenger cars, and to fill the gap in this field.

[0005] The utility model provides an engine valve drive mechanism that generates two valve motions, comprising an auxiliary cam and an auxiliary rocker arm, one end of the auxiliary rocker arm being connected to the auxiliary cam, the outline of the auxiliary cam being partially or entirely larger than the outline of a conventional cam of the engine, a connecting mechanism being provided between the auxiliary rocker arm and the conventional rocker arm of the engine, the connecting mechanism having a disconnection position and a connection position,

[0006] In the disconnection position, the auxiliary rocker arm is disconnected from the conventional rocker arm, and the gap between the auxiliary rocker arm and the conventional rocker arm causes the movement of the auxiliary cam to be lost. Only the movement generated by the conventional cam is transmitted to the engine valve through the conventional rocker arm, thereby forming the normal valve movement of the engine;

[0007] When in the connecting position, the auxiliary rocker arm is connected to the conventional rocker arm through the connecting mechanism, and the movement generated by at least the part where the auxiliary cam profile is larger than the conventional cam profile is transmitted to the engine valve through the auxiliary rocker arm and the conventional rocker arm, thereby forming the auxiliary valve movement of the engine.

[0008] Optionally, the connecting mechanism is located at the connecting station.

[0009] When the profiles of the auxiliary cams are all larger than the profiles of the conventional cams, the movement of the engine valve is generated by the auxiliary cams driving the auxiliary rocker arms and the conventional rocker arms;

[0010] When the profile of the auxiliary cam is partially larger than the profile of the conventional cam, the movement of the engine valve is generated by the portion of the auxiliary cam profile that is larger than the conventional cam profile driving the auxiliary rocker arm and the conventional rocker arm, and the conventional cam driving the conventional rocker arm.

[0011] Optionally, the relationship between the auxiliary valve movement and the normal valve movement includes at least one of the following three movements:

[0012] a. The auxiliary valve movement is opened earlier than the conventional valve movement,

[0013] b. The closing of the auxiliary valve movement is delayed than the conventional valve movement,

[0014] c. The lift of the auxiliary valve motion is greater than that of the normal valve motion.

[0015] Optionally, the normal valve motion includes intake valve motion, and the auxiliary valve motion includes delayed closing intake valve motion.

[0016] Optionally, the intake valve movement is driven by the conventional cam, and the delayed closing intake valve movement is driven by the portion of the auxiliary cam profile that is larger than the conventional cam profile, and the conventional cam combination. The lift generated by the portion of the auxiliary cam profile that is larger than the conventional cam profile is the auxiliary intake lift, and the auxiliary intake lift opens before the bottom dead center of intake and closes after the conventional intake lift ends.

[0017] Optionally, the lift of the delayed closing intake valve movement includes part of the normal intake lift and the auxiliary intake lift, and the part of the normal intake lift starts before the exhaust top dead center and ends when the auxiliary intake lift is opened.

[0018] Optionally, the normal valve movement of the engine includes exhaust valve movement, and the auxiliary valve movement includes early opening exhaust valve movement.

[0019] Optionally, the exhaust valve movement is driven by the conventional cam, and the early-opening exhaust valve movement is driven by the portion of the auxiliary cam profile that is larger than the conventional cam profile, and the conventional cam combination, and the lift generated by the portion of the auxiliary cam profile that is larger than the conventional cam profile is the auxiliary exhaust lift, which opens before the start of the conventional exhaust lift and closes after the bottom dead center of expansion.

[0020] Optionally, the connecting mechanism includes a connecting rod piston mechanism, which includes a first connecting rod, a second connecting rod and a connecting piston, one end of the first connecting rod and one end of the second connecting rod are rotatably connected, the other end of the first connecting rod is rotatably connected to the auxiliary rocker arm, and the other end of the second connecting rod is rotatably connected to one end of the connecting piston, and the contraction and extension between the first connecting rod and the second connecting rod changes the length of the connecting rod piston mechanism to lose or transmit the movement of the auxiliary cam.

[0021] Optionally, the connecting rod piston mechanism further includes a preload spring, and the preload spring changes the state between the first connecting rod and the second connecting rod from the extension to the contraction.

[0022] Optionally, an anti-fly-off spring is further included, wherein the anti-fly-off spring pushes the auxiliary rocker arm toward the auxiliary cam.

[0023] Compared with existing technologies, this new system offers significant and effective results. It utilizes an auxiliary cam and auxiliary rocker arm to produce a precisely controlled auxiliary valve lift, resulting in a smooth curve, no fluctuations, and low valve seating velocity. Furthermore, it boasts a simple and reliable structure, easy manufacturing and assembly, and a wide range of applications, including the intake Miller cycle and early exhaust opening. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the arrangement of rocker arms of the engine valve drive mechanism of the present invention.

[0025] Figure 2 It is a schematic diagram of the connecting rod piston mechanism in the auxiliary rocker arm of the engine valve drive mechanism of the present invention in a retracted state.

[0026] Figure 3 It is a schematic diagram of two types of valve lifts generated by the engine valve drive mechanism of the present invention. DETAILED DESCRIPTION

[0027] Figure 1 and 2 An embodiment of the engine valve drive mechanism that generates two valve motions is described as an example. Figure 1There is a conventional rocker arm 210 and an auxiliary rocker arm 220 for normal operation of the engine. The auxiliary rocker arm 220 and the conventional rocker arm 210 are rotatably arranged side by side on the rocker shaft 205 of the engine. A connecting mechanism 100 ( Figure 2 ). One end of the auxiliary rocker arm 220 is connected to the auxiliary cam 230, and one end of the conventional rocker arm 210 is connected to the conventional cam 215. The other end 236 of the conventional rocker arm 210 is close to the engine valve. A connecting mechanism 100 is provided between the other end of the auxiliary rocker arm 220 and the other end 236 of the conventional rocker arm 210. The conventional rocker arm 210 is also provided with a clearance adjustment mechanism 238 and an auxiliary clearance adjustment mechanism 248 (generally including a clearance adjustment screw, a locking nut, etc.). The auxiliary rocker arm 220 is connected (interacts) with the auxiliary clearance adjustment mechanism 248 of the conventional rocker arm 210 through the connecting mechanism 100. The clearance adjustment mechanism 238 adjusts the clearance between the conventional rocker arm 210 and the engine valve 300; the auxiliary clearance adjustment mechanism 248 adjusts the clearance between the auxiliary rocker arm 220 and the conventional rocker arm 210. It can also be understood that the auxiliary clearance adjustment mechanism 248 adjusts the clearance between the connecting mechanism 100 and the conventional rocker arm 210.

[0028] The conventional rocker arm 210 of this embodiment remains unchanged except for the addition of the auxiliary clearance adjustment mechanism 248, and will not be described again herein.

[0029] Figure 2 The auxiliary rocker arm 220 in the illustrated embodiment includes a connecting mechanism 100, which has two working positions: disconnection and connection. The connecting mechanism 100 here is a motion loss mechanism, specifically a connecting rod piston mechanism. The connecting rod piston mechanism 100 includes a first connecting rod 152, a second connecting rod 154 and a connecting piston 160. One end of the first connecting rod 152 and one end of the second connecting rod 154 are rotatably connected, the other end of the first connecting rod 152 is rotatably connected to the auxiliary rocker arm 220, and the other end of the second connecting rod 154 is rotatably connected to one end of the connecting piston 160. The auxiliary clearance adjustment mechanism 248 can be understood as adjusting the clearance between the connecting piston 160 of the connecting mechanism 100 and the conventional rocker arm 210. When the connecting rod piston mechanism 100 extends (becomes longer), the other end face of the connecting piston 160 is connected to the conventional rocker arm 210 (see Figure 1 ), it can be understood that the other end surface of the connecting piston 160 is connected to the auxiliary clearance adjustment mechanism 248 of the conventional rocker arm 210, or it can be understood that the extension of the connecting rod piston mechanism (connection position) connects the auxiliary rocker arm 220 and the conventional rocker arm 210, and the movement of the auxiliary cam 230 is transmitted to the engine valve 300 through the auxiliary rocker arm 220 and the conventional rocker arm 210, thereby forming the auxiliary valve movement of the engine. When the connecting rod piston mechanism 100 contracts (becomes shorter) (see Figure 2), the contraction between the first connecting rod 152 and the second connecting rod 154 causes a gap to be generated between the connecting piston 160 and the conventional rocker arm 210. It can be understood that a gap is generated between the other end face of the connecting piston 160 and the auxiliary gap adjustment mechanism 248 of the conventional rocker arm 210. It can also be understood that the contraction of the connecting rod piston mechanism (disconnection position) causes a gap to be generated between the auxiliary rocker arm 220 and the conventional rocker arm 210, canceling (losing) the movement of the auxiliary cam 230, and only the movement generated by the conventional cam 215 is transmitted to the engine valve 300 through the conventional rocker arm, and forms the conventional valve movement of the engine.

[0030] The relationship between the auxiliary valve movement and the conventional valve movement includes at least one of the following three movements: a. the opening of the auxiliary valve movement is earlier than the conventional valve movement, b. the closing of the auxiliary valve movement is delayed than the conventional valve movement, c. the lift of the auxiliary valve movement is greater than that of the conventional valve movement.

[0031] It should be noted that conventional valve motion can include intake valve motion and exhaust valve motion. When the conventional valve motion is intake valve motion, the conventional rocker arm is a conventional intake rocker arm, the auxiliary rocker arm is an auxiliary intake rocker arm, the conventional cam is a conventional intake cam, the auxiliary cam is an auxiliary intake cam, and the engine valve is an engine intake valve. When the conventional valve motion is exhaust valve motion, the conventional rocker arm is a conventional exhaust rocker arm, the auxiliary rocker arm is an auxiliary exhaust rocker arm, the conventional cam is a conventional exhaust cam, the auxiliary cam is an auxiliary exhaust cam, and the engine valve is an engine exhaust valve. When the conventional valve motion is intake valve motion, the auxiliary valve motion can be a delayed intake valve closing motion; when the conventional valve motion is exhaust valve motion, the auxiliary valve motion can be an early exhaust valve opening motion. Whether the delayed intake valve closing motion or the early exhaust valve opening motion is greater in lift than the conventional valve motion.

[0032] The angle between the first connecting rod 152 and the second connecting rod 154 of the connecting rod-piston mechanism 100 is between greater than 0° and less than or equal to 180°, and the minimum angle can be controlled by a stop mechanism. When the angle is a straight angle (180°), the first connecting rod 152 and the second connecting rod 154 are straightened by the connecting piston 160, and the connecting piston 160 is fully extended. When the angle decreases, the connecting piston 160 retracts, and the gap between the connecting piston 160 and the conventional rocker arm 210 increases. The range of variation of the angle between the first connecting rod 152 and the second connecting rod 154 of this embodiment is large, and the corresponding stroke of the connecting rod piston 160 is also large, resulting in a large lift of the valve 300, which increases the scope of application.

[0033] This embodiment also includes an anti-flying spring 298 ( Figure 2), the auxiliary rocker arm 220 is pushed toward the auxiliary cam 230 through the roller shaft 231 and the roller 235 to prevent the gap between the auxiliary rocker arm 220 and the conventional rocker arm 210 from causing impact when the connecting rod piston mechanism 100 retracts.

[0034] The operation process of this embodiment is as follows:

[0035] In the normal (or default) state, the connection mechanism is in the disconnect position. The control valve (not shown) is disconnected to unload the oil, and the oil pressure in the spring piston oil chamber 132 and the drive piston oil chamber 162 is zero. The preload spring 136 pushes the spring piston 130 out (upward), pushing the connection piston mechanism 100 to Figure 2 In the retracted (contracted) position shown, the clearance between the connecting piston 160 and the conventional rocker arm 210 is eliminated / the movement of the auxiliary cam 230 is lost, and the engine valve can only obtain the movement from the conventional cam 215 through the conventional rocker arm 210, resulting in the conventional valve lift 301 ( Figure 3 303 is the starting point (valve opening point), 305 is the highest point, and 311 is the end point (valve closing point).

[0036] When the auxiliary valve of the engine is required to move, the connecting mechanism 100 is in the connecting position. The control valve (not shown) is opened to supply oil, and the engine oil is supplied to the driving piston oil chamber 162 through the oil path (such as the oil hole (not shown) in the rocker arm shaft 205 and the oil channel 214 in the auxiliary rocker arm 220). The oil pressure pushes the driving piston 160 (note that the connecting piston and the driving piston are the same piston) out (to the left), Figure 2 The first connecting rod 152 and the second connecting rod 154 in the retracted position are straightened, and the connecting piston 160 is extended, eliminating the gap between the conventional rocker arm 210 and the auxiliary rocker arm 220, and connecting the auxiliary rocker arm 220 to the conventional rocker arm 210. It can be understood that the connecting piston 160 of the connecting mechanism 100 is connected to the auxiliary clearance adjustment mechanism 248 of the conventional rocker arm 210, and the movement of the auxiliary cam 230 is transmitted to the engine valve 300 of the engine, generating a portion of the auxiliary valve lift 302 of the engine that is different from the conventional valve lift 301 ( Figure 3 Of course, oil can also be supplied to the spring piston oil chamber 132 through the oil hole 213 at the same time to overcome the force of the preload spring 136 and push the spring piston 130 back (such as Figure 2 down), which makes it easier to Figure 2 The connecting rod piston mechanism 100 in the retracted position is pulled straight to the fully extended position.

[0037] In one embodiment of the present invention, the auxiliary cam 230 has a profile that is partially or entirely larger than the profile of the conventional cam 215. When the connecting mechanism 100 is in a connected position, the motion generated by at least the portion of the auxiliary cam 230 that is larger than the profile of the conventional cam 215 is transmitted to the engine valve 300 via the auxiliary rocker arm 220 and the conventional rocker arm 210, thereby generating auxiliary valve motion of the engine. For example, when the profile of the auxiliary cam 230 is entirely larger than the profile of the conventional cam 215, the motion of the engine valve 300 is generated by the auxiliary cam 230 driving the auxiliary rocker arm 220, which in turn drives the conventional rocker arm 210. When the profile of the auxiliary cam 230 is partially larger than the profile of the conventional cam 215, the motion of the engine valve 300 consists of two parts: one part is generated by the portion of the auxiliary cam 230 that is larger than the profile of the conventional cam 215 driving the auxiliary rocker arm 220 and driving the conventional rocker arm 210, and the other part is generated by the conventional cam 215 driving the conventional rocker arm 210. With such a design, auxiliary valve motion and conventional valve motion are formed by the contour design of the auxiliary cam 230 and the conventional cam 215 , which has a simple structure and is easy to process and produce.

[0038] The present invention adds a valve motion (lift) to the engine's operation, allowing the engine to select different valve motions according to different operating conditions. Note that the profile of the auxiliary cam 230 is partially or entirely larger than the profile of the conventional cam 215. When the entire profile of the auxiliary cam 230 is larger than the profile of the conventional cam 215, the auxiliary valve lift (second profile line 302) is generated solely by the auxiliary cam 230. When the profile of the auxiliary cam 230 is partially (the lift in a certain area) larger than the profile of the conventional cam 215, the auxiliary valve lift (second profile line 302) is generated by the auxiliary cam 230 and the conventional cam 215 in combination. For example, the solid line portion (303-304-305-306-308) of profile line 302 is generated by the conventional cam 215, while the dashed line portion (308-302-312) is generated by the auxiliary cam 230. In summary, the auxiliary valve lift (second profile line 302) is greater than the conventional valve lift (first profile line 301), that is, the second profile line 302 wraps the first profile line 301, including early opening, greater lift and delayed closing (one, two or all of them).

[0039] Figure 3The figure shows an example of valve lift for two valve motions produced by the present invention. The solid line 301 (303-304-305-306-308-301-311) is the normal valve lift curve of the engine (here, the normal intake lift curve), and the second valve lift curve 302 (303-304-305-306-308-302-312) is the auxiliary valve lift curve (the lift curve for delayed closing of the intake valve motion). The dotted line portion 308-302-312 (auxiliary intake lift) is provided by the auxiliary cam 21. 5 (the portion where the auxiliary cam 215 has a larger profile than the conventional cam 230) drives the auxiliary rocker arm 220, which opens the engine valve 300 (the engine intake valve) through the connecting mechanism 100 and the conventional rocker arm 210. This results in a delayed closing (the closing point is delayed from 311 to 312) compared to the conventional intake lift curve 301, generating a Miller cycle (reducing the engine's compression ratio so that the compression ratio is less than the expansion ratio), increasing the closing delay angle of the engine's intake valve, and reducing the engine's fuel consumption.

[0040] It should be noted that while conventional intake lift (intake valve motion) is driven by the conventional intake cam, delayed intake valve closing motion is driven by the portion of the auxiliary intake cam profile that is larger than the conventional intake cam profile, as well as a combination of the conventional intake cams. The lift generated by the portion of the auxiliary intake cam profile that is larger than the conventional intake cam profile is the auxiliary intake lift, which opens before intake bottom dead center and closes after the end of conventional intake lift. The delayed intake valve closing lift includes a portion of the conventional intake lift (303-304-305-306-308) and auxiliary intake lift (308-302-312). The portion of the conventional intake lift begins before exhaust top dead center and ends when the auxiliary lift opens. The Miller cycle generated by the design of the auxiliary intake cam and the conventional intake cam profile increases the engine intake valve closing delay angle, reduces engine fuel consumption, and has a simple structure that is easy to manufacture.

[0041] Furthermore, the engine's regular valve motion can also include the engine's exhaust valve motion, and the auxiliary valve motion includes early exhaust valve opening. The exhaust valve motion is driven by the regular exhaust cam, while the early exhaust valve opening is driven by the portion of the auxiliary exhaust cam profile that is larger than the regular exhaust cam profile, as well as the combination of the regular exhaust cam and the auxiliary exhaust lift. The auxiliary exhaust lift is the lift generated by the portion of the auxiliary exhaust cam profile that is larger than the regular exhaust cam profile. The auxiliary exhaust lift opens before the regular exhaust lift begins and closes after the bottom dead center of expansion. The design of the auxiliary intake cam and the regular intake cam profile allows for early exhaust valve opening, resulting in a simple structure and ease of manufacturing.

[0042] The above description should not be regarded as limiting the scope of the present invention, but rather as a specific example representing the present invention, from which many other variations are likely to arise. For example, the engine valve drive mechanism shown here can be used not only for intake valve drive, but also for exhaust valve drive; not only for delayed valve closing, but also for early valve opening, or to increase valve lift. In addition, the connection mechanism here is not limited to a motion loss mechanism or a connecting rod piston mechanism. In addition, the rotational connection between the connecting rod and the piston can be a pin (cylindrical surface) or a ball head (spherical surface). In addition, the anti-fly-off spring can also be placed in different orientations.

Claims

1. An engine valve drive mechanism that produces two valve motions, characterized in that: It includes an auxiliary cam and an auxiliary rocker arm. One end of the auxiliary rocker arm is connected to the auxiliary cam. The outline of the auxiliary cam is partially or completely larger than the outline of the conventional cam of the engine. A connecting mechanism is provided between the auxiliary rocker arm and the conventional rocker arm of the engine. The connecting mechanism has a disconnection position and a connection position. In the disconnection position, the auxiliary rocker arm is disconnected from the conventional rocker arm, and the gap between the auxiliary rocker arm and the conventional rocker arm causes the movement of the auxiliary cam to be lost. Only the movement generated by the conventional cam is transmitted to the engine valve through the conventional rocker arm, thereby forming the normal valve movement of the engine; When in the connecting position, the auxiliary rocker arm is connected to the conventional rocker arm through the connecting mechanism, and the movement generated by at least the part where the auxiliary cam profile is larger than the conventional cam profile is transmitted to the engine valve through the auxiliary rocker arm and the conventional rocker arm, thereby forming the auxiliary valve movement of the engine.

2. The engine valve drive mechanism for generating two valve motions according to claim 1, characterized in that: The connecting mechanism is located at the connecting station. When the profiles of the auxiliary cams are all larger than the profiles of the conventional cams, the movement of the engine valve is generated by the auxiliary cams driving the auxiliary rocker arms and the conventional rocker arms; When the profile of the auxiliary cam is partially larger than the profile of the conventional cam, the movement of the engine valve is generated by the portion of the auxiliary cam profile that is larger than the conventional cam profile driving the auxiliary rocker arm and the conventional rocker arm, and the conventional cam driving the conventional rocker arm.

3. The engine valve drive mechanism for generating two valve motions according to claim 1, characterized in that: The relationship between the auxiliary valve motion and the normal valve motion includes at least one of the following three motions: a. The auxiliary valve movement is opened earlier than the conventional valve movement, b. The closing of the auxiliary valve movement is delayed than the conventional valve movement, c. The lift of the auxiliary valve motion is greater than that of the normal valve motion.

4. The engine valve drive mechanism for generating two valve motions according to claim 1, characterized in that: The normal valve motion includes an intake valve motion, and the auxiliary valve motion includes a delayed closing intake valve motion.

5. The engine valve drive mechanism for generating two valve motions according to claim 4, characterized in that: The intake valve movement is driven by the conventional cam, and the delayed closing intake valve movement is driven by the portion of the auxiliary cam profile that is larger than the conventional cam profile and the conventional cam combination. The lift generated by the portion of the auxiliary cam profile that is larger than the conventional cam profile is the auxiliary intake lift, and the auxiliary intake lift opens before the intake bottom dead center and closes after the conventional intake lift ends.

6. The engine valve drive mechanism for generating two valve motions according to claim 5, characterized in that: The lift of the delayed closing intake valve movement includes a portion of the normal intake lift and the auxiliary intake lift, wherein the portion of the normal intake lift starts before exhaust top dead center and ends when the auxiliary intake lift is opened.

7. The engine valve drive mechanism for generating two valve motions according to claim 1, characterized in that: The normal valve motion of the engine includes exhaust valve motion, and the auxiliary valve motion includes early-opening exhaust valve motion.

8. The engine valve drive mechanism for generating two valve motions according to claim 7, characterized in that: The exhaust valve movement is driven by the conventional cam, and the early-opening exhaust valve movement is driven by the portion of the auxiliary cam profile that is larger than the conventional cam profile and the conventional cam combination. The lift generated by the portion of the auxiliary cam profile that is larger than the conventional cam profile is the auxiliary exhaust lift, and the auxiliary exhaust lift opens before the start of the conventional exhaust lift and closes after the bottom dead center of expansion.

9. The engine valve drive mechanism for generating two valve motions according to claim 1, wherein: The connecting mechanism includes a connecting rod piston mechanism, which includes a first connecting rod, a second connecting rod and a connecting piston. One end of the first connecting rod is rotatably connected to one end of the second connecting rod, the other end of the first connecting rod is rotatably connected to the auxiliary rocker arm, and the other end of the second connecting rod is rotatably connected to one end of the connecting piston. The contraction and extension between the first connecting rod and the second connecting rod changes the length of the connecting rod piston mechanism to lose or transmit the movement of the auxiliary cam.

10. The engine valve drive mechanism for generating two valve motions according to claim 9, characterized in that: The connecting rod piston mechanism further includes a preload spring configured to change the state between the first connecting rod and the second connecting rod from the extension to the contraction.

11. The engine valve drive mechanism for generating two valve motions according to claim 1, characterized in that: An anti-fly-off spring is also included, and the anti-fly-off spring pushes the auxiliary rocker arm toward the auxiliary cam.

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