CN111550294A

CN111550294A - Full-variable tappet cup

Info

Publication number: CN111550294A
Application number: CN202010528654.7A
Authority: CN
Inventors: 崔靖晨; 隆武强; 田华; 孟相宇; 礼博; 王阳
Original assignee: Dalian University of Technology
Current assignee: Dalian University of Technology
Priority date: 2020-06-11
Filing date: 2020-06-11
Publication date: 2020-08-18
Also published as: WO2021248967A1; JP2023525208A

Abstract

The invention discloses a full-variable tappet cup which comprises a fixed body, a driving plunger, a return spring and a driven plunger, wherein the driving plunger and the driven plunger are respectively in sliding fit with the fixed body; the driving oil cavity is communicated with the driven oil cavity; the fixing body is provided with a main oil hole, the driving oil cavity is communicated with the main oil hole through a plurality of fixing holes, the driven oil cavity is communicated with the main oil hole through a plurality of buffer holes, the main oil hole is communicated with the energy accumulator through an oil way, and the oil way is provided with a hydraulic valve; the return spring provides spring force to ensure that the mutual contact parts between the active plunger and the cam are always kept in contact. The fully-variable tappet cup can improve the valve fullness coefficient and the high rotating speed range of the engine applicable to a valve mechanism on the premise of not changing the engine body, having few parts and meeting the valve seating speed standard.

Description

Full-variable tappet cup

Technical Field

The invention relates to the technical field of engine valve actuating mechanisms, in particular to a fully-variable tappet cup.

Background

The engine valve mechanism adopts a cam to drive a valve component directly or through a valve transmission set. The positions of the camshafts are different, and the specific structures of the valve transmission sets are different, for example, when the bottom camshaft is adopted, the valve transmission sets comprise a tappet cup, a push rod, a rocker arm and the like; when the camshaft moves upwards, the valve transmission set comprises a tappet cup, a rocker arm and the like; when the camshaft position continues to move upwards and becomes the overhead camshaft, the valve transmission set comprises a rocker arm or no valve transmission set, namely, the cam directly drives the valve assembly. When one cam drives a plurality of valve assemblies simultaneously, a structure of a branched rocker arm or a rocker arm gas-filling valve bridge is generally adopted.

With the increasingly stricter energy-saving and emission-reducing regulations of the engine, the variable valve mechanism becomes a research hotspot because the variable valve mechanism can change the valve operating parameters to greatly improve the fuel economy and the emission of the engine. Compared with a compression ignition engine (such as a diesel engine), the variable valve mechanism can greatly reduce the pumping loss of the ignition engine (such as a gasoline engine) and improve the fuel economy, so at present, most of the variable valve mechanisms are designed and developed aiming at small ignition engines (such as passenger vehicles adopting gasoline engines). The structure is of a top-mounted camshaft type, and the structure has the characteristics of light weight of a moving part and small inertia force of the moving part. The two-stroke low-speed marine engine adopts a camless electro-hydraulic valve driving mechanism due to the reasons of large volume, extremely low rotating speed (below 300 r/min), critical oil consumption index and the like, the mechanism can realize a completely flexible and variable valve operation event, has small application range due to the problems of low response speed, large installation space requirement and the like, is only matched with the two-stroke low-speed marine engine, and is difficult to be used for engines with higher rotating speed.

With the implementation of the regulations of the european six, the national six, the IMOTier III, the carbon emission, etc. and in order to cope with the stricter oil consumption and emission regulations in the future, the development of the variable valve mechanism for medium and large-sized engines with medium and high speed, such as the engines of ships, locomotives, trucks, engineering machinery, etc., becomes a new hot spot. The engine has the characteristics of large volume, complex structure, higher rotating speed, heavy mass of a moving part of the valve actuating mechanism, large inertia force of the moving part and the like. This requires that the variable valve mechanism satisfy the following requirements at the same time:

1) the engine can be installed and used on the basis of not changing the engine body; the engine body includes, but is not limited to, a block containing a cooling water jacket, a cylinder head containing a cooling water jacket and an intake/exhaust passage, a crankshaft-to-camshaft transmission mechanism (mainly determined by the camshaft position), and the like. If the newly designed variable valve mechanism interferes with the engine body or the position of the camshaft is required to be changed, namely the engine body is required to be changed, thousands of yuan or more is often required, the initial cost of the application of the variable valve mechanism is too high, the user acceptance is reduced, and the industrialization prospect of the mechanism is seriously influenced.

2) And simultaneously, a plurality of design requirements of the valve actuating mechanism are met. The method mainly comprises the following steps: a) the continuous, flexible and independent adjustment of the valve operation parameters at least including the valve opening timing, the valve closing timing and the like; b) the valve opening speed and the valve closing speed are high enough (the higher the engine rotating speed is, the higher the valve opening and closing speed is, the highest valve opening and closing speed can reach 4-5m/s or even higher), and the valve fullness coefficient is large enough (generally not less than 0.5 when calculated according to the valve zero lift), so that the high enough inflation efficiency of the engine is ensured, and finally the dynamic property, the fuel economy and the emission index of the engine are ensured; c) under the conditions of variable operation of the air valve and 1.15-1.3 times of the maximum rotating speed of the engine, the stress of each part does not exceed the standard, the seating time of the air valve is short enough, the seating speed of the air valve is less than or equal to 0.3m/s, and the like. The valve seating time is determined by the maximum engine speed and the allowed seating duration, e.g., 1000r/min, 1500r/min, 2000r/min, 2500r/min, 3000r/min, 3500r/min, with the damping being accomplished at 1.2 times the maximum speed and within 20 deg.C A, and the damping time being < 2.78ms, < 1.85ms, < 1.39ms, < 1.11ms, < 0.93ms, < 0.79 ms. Because the higher the engine rotating speed is, the faster the valve opening and closing speed is, the shorter the required valve seating time is, and the finally realized valve seating speeds are basically consistent, along with the improvement of the engine rotating speed, the valve deceleration is required to be greatly improved, namely the seating buffer force provided by the valve actuating mechanism is required to be greatly improved, which provides a very high requirement on the reliability of the valve actuating mechanism; e) the valve operation consistency and repeatability are good under different engine speeds, environmental conditions and control parameters; d) the number of parts is simple, and the processing cost is low. As shown in fig. 1, where L represents a valve lift, and T1 represents an initial valve opening stage in which a short crank angle is required to be occupied and the valve is opened quickly; t2 represents a valve quick opening period, the valve is required to be quickly opened in the valve quick opening period, the maximum lift of the valve meets the requirement, the valve plumpness coefficient is large enough, and the like; t3 represents a valve rapid closing period, in which the valve is required to be rapidly closed, the maximum lift of the valve meets the requirement, the valve plumpness coefficient is large enough, and the like; t4 represents the sitting buffering period, the crankshaft rotation angle occupied by the sitting buffering period is required to be short, and the sitting speed is less than or equal to 0.3 m/s.

The valve transmission group of the traditional valve mechanism has invariable transmission characteristics, good running consistency and repeatability, and meets the index requirements of the valve opening and closing speed, fullness coefficient, valve seating time, valve seating speed, component reliability and the like by means of cam profile design.

At present, a variable valve mechanism for a medium-large engine mostly cancels an invariable valve transmission set in a traditional valve mechanism, and a new variable valve transmission set is redesigned to realize the flexible variability of valve operation parameters, which mainly comprises:

1) mechanical CVVL mechanism: its advantages are high reliability and high uniformity and repeatability of valve parameters. It has problems to be perfected: a) the higher the degree of valve flexibility, the higher the need for engine block modification, and the higher the initial cost. b) The higher the degree of flexibility of the valve is, the more complicated the variable valve mechanism itself is, and the higher the processing cost is. c) To realize different valve operating parameters, the valve train needs to be in different controlled states, which results in that when valve operating events such as valve early closing are realized, the cam blade position corresponding to the valve seating buffer period does not reach the seating buffer period on the cam profile, that is, the seating buffer period on the cam profile cannot play a role in valve seating buffer, so that the control of the valve seating buffer speed is a difficult problem to be solved by all variable valve mechanisms, especially for mechanical CVVL mechanisms.

2) Electro-hydraulic CVVL mechanism: for example, in 2019, the inventor proposes an electro-hydraulic CVVL mechanism with a novel integrated fully-variable fulcrum in a multi-mode fully-variable mechanism, and the electro-hydraulic CVVL mechanism has the advantages that the degree of variable flexibility of a valve is high; the hydraulic parts are flexibly connected, so that the requirement for changing the engine body is reduced, and even the engine body can be unchanged; the number of parts is small, and the processing and assembling cost is reduced. It has problems to be perfected: a) for an electro-hydraulic CVVL mechanism, when a valve is closed in advance, a seating buffer period on a cam profile cannot play a role in valve seating buffer, and the problem of how to meet various requirements of the valve mechanism design is solved. The fully-variable fulcrum in the application adopts a buffering scheme of the buffering table, the variation curve of the seating buffering equivalent area along with the valve lift is limited by the structure, the optimal buffering area curve is difficult to obtain, the problems of considering one another between the requirements of quick opening and closing, seating buffering, compact structure and the like of the valve at high speed of the engine are solved, the application of the mechanism on the high-speed engine is limited, and further research and improvement are needed. b) The valve operation consistency and repeatability of the electro-hydraulic CVVL mechanism are poorer than those of the mechanical CVVL mechanism due to hydraulic fluctuation characteristics, machining assembly differences, initial state differences of each cycle and the like, and the problem of how to improve the valve operation consistency and repeatability needs to be solved. The patent with application number 201910237039.8 discloses a multi-mode fully variable mechanism, adopt the buffering scheme of cushion table, the real-time clearance between cushion table and the cushion table seat is decided by the real-time stroke of driven plunger completely, in the valve opening initial stage and valve take a seat the buffering period, all there is real-time clearance to decide the size of the effort that driven oil pocket applyed to the driven plunger to the relevant motion piece of valve subassembly, this effort has decided the valve real-time stroke again in turn, this is a strong coupling process, and the valve opens the hydraulic oil fluctuation state in initial stage and directly influences subsequent valve quick opening period, and then influences the valve quick closing period, and then influences the valve take a seat the buffering period, finally can influence the hydraulic oil fluctuation state in next cycle valve opening initial stage, this is a strong coupling process again. After the factors such as hydraulic fluctuation pass through the coupling process, great uncertainty exists in the valve operation condition, which is relatively unfavorable for the precise control, operation consistency and repeatability improvement of the valve operation parameters of the electrohydraulic CVVL mechanism, and further research and improvement are needed.

And adopt the cushion collar scheme still to have the valve to open and close fast under the engine high speed, take a seat buffering and compact structure etc. the aspect of considering this problem of losing one another, its reason lies in: under the condition that the diameter of the driven plunger is not changed, namely the quality of a moving part is not changed, in order to meet the requirements that the valve seating time is short enough and the valve seating speed is less than or equal to 0.3m/s under the high rotating speed of an engine, the time when the buffer table is inserted into the buffer table seat is enough early to ensure that the deceleration time of the driven plunger is long enough, and the annular area of a driven oil cavity after the buffer table is inserted into the buffer table seat is large enough to ensure that the pressure of the driven oil cavity is rapidly increased, namely, the deceleration of a relative moving part from a valve assembly to the driven plunger is large enough. On one hand, the hydraulic oil of the active oil cavity can only act on the buffer table in a long time at the initial stage of opening the valve, so that the overall opening speed of the valve is further low, and the inflation requirement of the engine at a high rotating speed is difficult to meet; on the other hand, the area of the buffer table (the area of the driven plunger minus the annular area of the driven oil cavity) is reduced, and further the initial stage of opening the valve is caused. If the area diameter of the buffer table is increased by increasing the area of the driven plunger to reduce the pressure of the driving oil cavity, the area of the driving plunger is increased to ensure that the maximum lift of the cam and the maximum lift of the valve are not changed due to the increase of the area of the driven plunger, the size of a spring of the driving plunger is increased by the area of the driving plunger, and finally the mass of a moving part is greatly increased, so that the driving force and the resistance required in the operation process of the valve are increased, and the area diameter of the buffer table is further increased to ensure that the pressure of the driving oil cavity does not exceed the standard when the valve is opened; in order to ensure that the pressure of the driven oil cavity, the seating buffer time and the final seating speed do not exceed the standard, the annular area needs to be greatly increased. Obviously, the scheme of increasing the area of the driven plunger is difficult to satisfy a plurality of requirements of the valve train design at the same time. Further, the above method is also not feasible in consideration of the engine installation space. Therefore, the buffering scheme of the buffering table is only suitable for engines with low engine rotating speeds.

Disclosure of Invention

The invention aims to provide a fully-variable tappet cup, which is used for solving the problems in the prior art, ensuring that the valve seating speed reaches the standard, improving the valve plumpness coefficient and improving the high rotating speed range of an engine applicable to a valve actuating mechanism.

In order to achieve the purpose, the invention provides the following scheme:

the invention provides a full-variable tappet cup which comprises a fixed body, a driving plunger, a return spring and a driven plunger, wherein the driving plunger and the driven plunger are respectively in sliding fit with the fixed body; the driving oil cavity and the driven oil cavity are separated by a buffer pedestal fixedly connected with the fixed body, one end of the driven plunger close to the buffer pedestal is provided with a buffer table, the buffer pedestal is provided with a through hole corresponding to the buffer table, the buffer table can be inserted into the through hole, and the driving oil cavity is communicated with the driven oil cavity through the through hole; the fixing body is provided with a main oil hole, the driving oil cavity is communicated with the main oil hole through a plurality of fixing holes, the driven oil cavity is communicated with the main oil hole through a plurality of buffer holes, the main oil hole is communicated with the energy accumulator through an oil path, and the oil path is provided with a hydraulic valve; the return spring provides spring force to ensure that the mutual contact parts between the active plunger and the cam are always kept in contact.

Preferably, a plunger sleeve is further fixedly arranged in the fixed body, and the driving plunger and/or the driven plunger are/is in sliding fit with the plunger sleeve respectively.

Preferably, the buffer hole and/or the fixing hole are/is arranged on the plunger sleeve; the buffering pedestal and the plunger sleeve are integrally formed, and the driving oil cavity and/or the driven oil cavity are/is located in the plunger sleeve; an intermediate oil cavity is formed between the plunger sleeve and the fixing body, and the main oil hole, the buffer hole and the fixing hole are respectively communicated with the intermediate oil cavity.

Preferably, a plurality of buffer grooves are provided on a side wall surface of the buffer table or the buffer base.

The invention also provides a full-variable tappet cup which comprises a fixed body, a driving plunger, a return spring and a driven plunger, wherein the driving plunger and the driven plunger are respectively in sliding fit with the fixed body; the driving oil cavity is communicated with the driven oil cavity through a one-way valve hole, a one-way valve is arranged on the one-way valve hole, and hydraulic oil can only flow from the driving oil cavity to the driven oil cavity in a one-way mode through the one-way valve; the fixing body is provided with a main oil hole, the driving oil cavity is communicated with the main oil hole through a plurality of fixing holes, the driven oil cavity is communicated with the main oil hole through a plurality of buffer holes, the main oil hole is communicated with the energy accumulator through an oil path, and the oil path is provided with a hydraulic valve; the return spring provides spring force to ensure that the mutual contact parts between the active plunger and the cam are always kept in contact.

Preferably, the buffer hole and/or the fixing hole are/is arranged on the plunger sleeve; the one-way valve hole is formed in the plunger sleeve, and the driving oil cavity and/or the driven oil cavity are/is located in the plunger sleeve; an intermediate oil cavity is formed between the plunger sleeve and the fixing body, and the main oil hole, the buffer hole and the fixing hole are respectively communicated with the intermediate oil cavity.

Compared with the prior art, the fully-variable tappet cup has the following technical effects:

the fully-variable tappet cup can realize the buffer seating of the driven piston on the premise of not changing an engine body and extremely small number of parts, and the seating speed of the valve is less than or equal to 0.3 m/s. The fully-variable tappet cup can realize flexible and independent adjustment of the operating parameters of the valve, improves the fullness coefficient by more than 4-12% under the same maximum rotating speed of an engine, improves the maximum rotating speed range of the adaptive engine by at least 4-9%, and has wide application range; meanwhile, the engine can be installed and used on the basis of not changing the engine body, the opening speed of the valve and the closing speed of the valve are high enough, and the condition that the stress of each part does not exceed the standard, the seating time of the valve is short enough and the like under the condition of high rotating speed of the engine can be ensured; the design of the buffer table and the buffer holes can weaken the coupling effect, and the controllability, the consistency and the repeatability of the operation of the air valve can be optimized in a small degree, while the design of the check valve and the buffer holes can eliminate the coupling effect, and the controllability, the consistency and the repeatability of the operation of the air valve can be greatly optimized.

Drawings

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

FIG. 1 is a graph of valve lift as a function of valve operating period;

FIG. 2 is a schematic structural view of a fully variable tappet according to a first embodiment of the present invention;

FIG. 3 is a schematic partial structural view of a second embodiment of a fully variable tappet according to the present invention;

FIG. 4 is a schematic structural view of a third embodiment of a fully variable tappet cup according to the present invention;

FIG. 5 is a schematic structural view of a fourth embodiment of a fully variable tappet cup according to the present invention;

FIG. 6 is a schematic structural view of a fully variable tappet cup according to a fifth embodiment of the present invention;

FIG. 7 is a comparison of valve lift curves for different approaches in a fully variable tappet of the present invention;

wherein: 1-driven plunger, 101-buffer table, 1011-buffer groove, 2-plunger sleeve, 201-buffer hole, 202-buffer table seat, 203-fixed hole, 3-fixed body, 301-total oil hole, 4-driving plunger, 5-reset spring, 6-driving oil cavity, 7-driven oil cavity, 8-hydraulic valve, 9-energy accumulator, 10-one-way valve shell, 11-one-way valve spring, 12-one-way valve core and 13-one-way valve hole.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Example one

As shown in fig. 2: the fully-variable tappet cup comprises a fixed body, a driving plunger 4, a return spring 5 and a driven plunger 1, wherein a plunger sleeve 2 is fixedly arranged in the fixed body, and the driving plunger 4 and the driven plunger 1 are respectively in sliding fit with the plunger sleeve 2; a driving oil cavity 6 and a driven oil cavity 7 are arranged in the plunger sleeve 2, one end of the driving plunger 4 is positioned in the driving oil cavity 6, and one end of the driven plunger 1 is positioned in the driven oil cavity 7; the driving oil cavity 6 and the driven oil cavity 7 are separated by a buffer pedestal 202 fixedly connected with the fixing body, one end, close to the buffer pedestal 202, of the driven plunger 1 is provided with a buffer table 101, the buffer table 202 is provided with a through hole corresponding to the buffer table 101, the buffer table 101 can be inserted into the through hole, the driving oil cavity 6 is communicated with the driven oil cavity 7 through the through hole, and the buffer pedestal 202 and the plunger sleeve 2 are integrally formed.

The fixing body is provided with a main oil hole 301, the driving oil cavity 6 is communicated with the main oil hole 301 through a plurality of fixing holes 203, the driven oil cavity 7 is communicated with the main oil hole 301 through a plurality of buffer holes 201, and the buffer holes 201 and the fixing holes 203 are both arranged on the plunger sleeve 2; an intermediate oil cavity is formed between the plunger sleeve 2 and the fixing body, and the main oil hole 301, the buffer hole 201 and the fixing hole 203 are respectively communicated with the intermediate oil cavity. The main oil hole 301 is communicated with the energy accumulator 9 through an oil path, and a hydraulic valve 8 is arranged on the oil path.

The return spring 5 provides a spring force to ensure that all the mutual contact parts from the active plunger to the cam are always in a contact state, in the embodiment, the active plunger 4 is inserted into the return spring 5, one end of the return spring 5 is abutted against the active plunger 4, and the other end of the return spring is abutted against the plunger sleeve 2. The bottom end of the active plunger 4 is in contact with the cam blade, the cam blade drives the active plunger 4 to move, and the shape, size and the like of the bottom end of the active plunger 4 can be adaptively designed in practical application for the convenience of the bottom end of the active plunger 4 and the cam blade.

It should be noted that: the buffer hole 201 is arranged on the side wall surface of the plunger sleeve 2; when the valve is completely closed, most of the orifice area of the buffer hole 201 is shielded by the driven plunger 1, and the actual opening area is very small or even zero. When the valve is completely closed and the actual opening area of the buffer holes 201 is not zero, the area which is not zero may be the area of some buffer holes 201 which are not shielded by the driven plunger 1, or some buffer holes 201 which are not shielded at all, and the positions of the buffer holes 201 which are not shielded at all on the side of the driven oil chamber 7 may be arranged on the side wall surface or the end surface of the plunger sleeve 2; in specific application, the plunger sleeve 2 can be designed in an integrated manner or in a split type structure; the main oil hole 301 and the fixing hole 203 may be combined into the same hole. An intermediate oil chamber may be formed between the plunger sleeve 2 and the fixed body 3, or may not be provided.

The fully-variable tappet cup of the embodiment adopts a structure of the buffer hole 201 and the buffer table 101, and the area of the buffer table 101 is estimated according to the upper limit of the pressure of the active oil cavity 6 at the initial stage of opening the valve; estimating an annular area, a change curve of the buffer holes 201 and a change curve of a gap between the buffer table 101 and the buffer table seat 202 according to the optimization target that the pressure of the driven oil cavity 7 is stable and does not exceed the standard, the seating time is shortest, the seating speed is less than or equal to 0.3m/s, and the number of the buffer holes 201 is the least when the valve is seated and buffered; based on the above known results and the valve closing speed, the variation curves of the cushion holes 201 and the variation curves of the clearances between the cushion table 101 and the cushion table base 202 during the valve quick opening period and the valve quick closing period are estimated, and finally the shapes of the cushion table 101 and the cushion table base 202, the number of the cushion holes 201, and the size and the position of each hole are determined. Compared with a buffering scheme only adopting the buffering table 101, the buffering scheme of the buffering table 101 and the buffering holes 201 can distribute the design of the buffering table 101 to the design of the buffering table 101 and the buffering holes 201, and can obtain an ideal change curve of the equivalent buffering area along with the valve lift, so that the problems that the valve is rapidly opened and closed, the valve is seated for buffering, the structure is compact and the like in the high-speed engine of the scheme are solved, and various indexes of a gas distribution system and the maximum speed range of the engine applicable to the scheme are improved.

The working process of the fully variable tappet cup of the embodiment is as follows:

when the cam lobe is acted upon by the lift, the cam lobe causes the drive plunger 4 to move upwardly. When the valve is in a closed state and the hydraulic valve 8 is opened, the driven plunger 1 is kept still due to the action of the valve spring force, namely the valve is kept in a closed state, the driving plunger 4 moves upwards, and hydraulic oil in the driving oil cavity 6 enters the energy accumulator 9 through the hydraulic valve 8. When the hydraulic valve 8 is closed, the hydraulic oil of the driving oil cavity 6 mainly acts on the buffer table 101 to push the driven plunger 1 to overcome the spring force of the valve to move upwards and open the valve; with the upward movement of the driven plunger 1, the cushion table 101 gradually moves upward, the clearance between the cushion table 101 and the cushion table base 202 gradually increases, the amount of insertion of the cushion table 101 into the cushion table base 202 gradually decreases, and the actual opening area of the cushion hole 201 gradually increases, and the drive oil chamber 6 not only acts on the cushion table 101 but also gradually passes through a certain throttling action, enters the driven oil chamber 7 from the actual opening portion of the cushion hole 201 and the clearance between the cushion table 101 and the cushion table base 202, and continues to open the valve. Since the hydraulic oil in the drive oil chamber 6 mainly acts on the cushion table 101 in addition to the very short time in the initial period of the valve opening, which results in a large pressure in the drive oil chamber 6 in the period of time, the hydraulic oil in the drive oil chamber 6 can enter the driven oil chamber 7 through the actual opening portion of the cushion hole 201 and the gap between the cushion table 101 and the cushion table base 202 in the rapid valve opening period occupying the crank angle, which greatly reduces the pressure in the drive oil chamber 6 and increases the valve opening speed, even when the amount of insertion of the cushion table 101 into the cushion table base 202 is still large, i.e., compared with the cushion scheme of the cushion table 101, the scheme can enter the rapid valve opening period earlier, which is very beneficial to increase the fullness coefficient.

When the valve is in the open state and the hydraulic valve 8 is opened again in the rising action of the cam vane, the hydraulic oil in the slave oil chamber 7 flows out through the actually opened portion of the buffer hole 201 and the gap between the buffer table 101 and the buffer table base 202 by the valve spring force, and enters the accumulator 9 through the hydraulic valve 8 together with the hydraulic oil in the master oil chamber 6. When the valve is in a large lift range, the flow area of hydraulic oil flowing out of the driven oil cavity 7 is large, the valve closing speed is high, along with descending of the driven plunger 1, after the hydraulic oil enters a sitting buffering period, the buffering hole 201 is gradually shielded, the gap between the buffering table 101 and the buffering table seat 202 is also gradually reduced, the throttling effect when the hydraulic oil in the driven oil cavity 7 flows out is increased, the pressure of the driven oil cavity 7 is increased, the movement of the driven plunger 1 and a corresponding valve assembly is hindered, and therefore the purpose of valve sitting buffering is achieved.

The drive plunger 4 spring causes the drive plunger 4 to move downwardly when the cam blade lowering segment is active. When the hydraulic valve 8 is closed, the driving plunger 4 moves downwards to cause the pressure of the driving oil cavity 6 to be reduced, hydraulic oil in the driven oil cavity 7 enters the driving oil cavity 6 under the action of the valve spring force, and the valve is gradually closed. When the hydraulic valve 8 is opened, under the action of the valve spring force, hydraulic oil in the driven oil cavity 7 flows out, the valve is gradually closed, and as the driven oil cavity 7, the driving oil cavity 6 and the energy accumulator 9 are communicated, compared with the closing of the hydraulic valve 8, the closing speed of the valve is higher, so that the closing timing of the valve is advanced. The process of achieving a seated cushion is similar to that before and is not repeated.

The control method of the fully variable tappet cup of the embodiment is as follows:

the flexible and continuous variable of the valve operation rule can be realized by controlling the opening and closing timing of the hydraulic valve 8, for example, the hydraulic valve 8 is opened in advance at the initial stage of rising of the cam blade, and the flexible adjustment of the first opening timing of the valve is realized by controlling the first closing timing of the hydraulic valve 8. In the rising stage of the cam blade, the flexible adjustment of the closing timing of the valve is realized by controlling the re-opening timing of the hydraulic valve 8, and the corresponding closing timing of the valve is determined by the first closing timing of the hydraulic valve 8, the re-opening timing of the hydraulic valve 8, the cam profile and the engine speed; the flexible adjustment of the second opening timing of the valve is realized by controlling the hydraulic valve 8 to close the timing again; by analogy, the valve can be flexibly and variably opened for multiple times. When entering the descending section of the cam blade, when the hydraulic valve 8 keeps closing, the corresponding valve closing timing is determined by the last closing timing of the hydraulic valve 8, the cam profile and the engine speed when acting on the ascending section of the cam blade; the flexible adjustment of the valve closing timing is realized by controlling the opening timing of the hydraulic valve 8 in the descending section, and the corresponding valve closing timing is determined by the closing timing of the hydraulic valve 8 at the last time when the hydraulic valve acts on the ascending section of the cam blade, the opening timing of the hydraulic valve 8 when the hydraulic valve acts on the descending section of the cam blade, the cam profile and the engine speed.

The fully-variable tappet cup of the embodiment realizes an ideal change curve of the equivalent buffering area along with the valve lift, so that the crank angle occupied by the initial valve opening stage and the sitting buffering stage is shortened, the buffering stroke is also reduced, the quick valve opening stage and the quick valve closing stage are increased, the fullness coefficient is improved, and the fullness coefficient is improved by 2-5% under the same maximum engine speed; the pressure of the driving oil cavity 6 is reduced and the pressure of the driven oil cavity 7 is increased at the initial stage of opening the valve, and the pressure of the driven oil cavity 7 is reduced at the seating buffer stage; the maximum rotating speed range of the adaptive engine is improved by 4-9%.

Example two

As shown in fig. 3, the structure, operation process and control method of the fully variable tappet cup of the present embodiment are the same as those of the fully variable tappet cup provided in the first embodiment, except that: the side wall of the buffer table 101 in the fully variable tappet of the embodiment is further provided with a buffer slot 1011, and the buffer slot 1011 can also be arranged on the side wall of the buffer table base 202 in practical application. By adjusting the change curve of the gap between the buffer stage 101 and the buffer stage 202, the change curve of the actual opening area of the buffer hole, and the size of the buffer slot 1011, various performances of the valve train can be further improved. Compared with a scheme of adding a buffer pedestal on a buffer table without a buffer groove 1011, the buffer groove 1011 can further shorten the crank angle and the buffer stroke occupied by the valve in the initial opening stage, increase the crank angle occupied by the valve in the quick opening period and the valve in the quick closing period, and further improve the fullness coefficient by 1-3%; the pressure of the driving oil cavity 6 is reduced and the pressure of the driven oil cavity 7 is increased at the initial stage of opening the valve, and the pressure of the driven oil cavity 7 is reduced at the seating buffer stage; the maximum rotating speed range of the adaptive engine is improved by 2-6%.

EXAMPLE III

As shown in fig. 4, the structure, operation process and control method of the fully variable tappet cup of the present embodiment are the same as those of the fully variable tappet cup provided in the first embodiment, except that: in the fully variable tappet of the present embodiment, a cavity is formed in one end of the active plunger 4 close to the buffer pedestal 202, corresponding to the return spring 5, the return spring 5 is inserted into the cavity, one end of the return spring 5 abuts against the buffer pedestal 202, and the other end abuts against the active plunger 4.

In addition, two return springs 5 can be provided, namely a first return spring and a second return spring, the active plunger 4 is inserted into the first return spring, one end of the first return spring abuts against the active plunger 4, and the other end of the first return spring abuts against the plunger sleeve 2; one end of the active plunger 4 close to the buffer pedestal 202 is provided with a cavity corresponding to the second return spring, the second return spring is inserted into the cavity, one end of the second return spring abuts against the buffer pedestal 202, and the other end of the second return spring abuts against the active plunger 4.

Example four

As shown in fig. 5, the structure and control method of the fully variable tappet cup of the present embodiment are the same as those of the fully variable tappet cup provided in the first embodiment, except that: in the fully-variable tappet of the embodiment, a design scheme of a one-way valve and a buffer hole 201 is adopted, and a buffer table 101 and a buffer table seat 202 are not arranged, specifically, a driving oil cavity 6 is communicated with a driven oil cavity 7 through a one-way valve hole 13, the one-way valve hole 13 is arranged on a plunger sleeve 2, a one-way valve for controlling the one-way valve hole 13 is arranged in the driven oil cavity 7, and the one-way valve comprises a one-way valve shell 10, a one-way valve spring 11 and a one-way valve core 12; it should be noted that, on the basis of ensuring that the hydraulic oil can only flow from the driving oil chamber 6 to the driven oil chamber 7 in one direction, the check valve may be arranged in the driving oil chamber 6 or in the check valve hole 13; in addition, strictly speaking, since the opening and closing of the check valve requires a process which may take a short time, at a certain moment when the check valve is not completely closed, there is a phenomenon that a minute amount of hydraulic oil flows from the driven oil chamber 7 into the driving oil chamber 6, but is negligible with respect to the amount of hydraulic oil flowing from the driving oil chamber 6 into the driven oil chamber 7.

The fully-variable tappet cup adopts a structure of the buffer hole 201 and the one-way valve, and the one-way valve ensures that the flow area of hydraulic oil entering the driven oil cavity 7 from the driving oil cavity 6 is not limited when the valve is opened at the initial stage, namely, the valve is ensured to be opened fast enough; when the valve is closed, the check valve is closed, and along with the descending of driven plunger 1, the actual area of opening of constantly changing buffer hole 201, confirm quantity, each hole size and the position of buffer hole 201 through optimizing, realized: the actual opening area of the buffer hole 201 in the rapid valve closing period is large enough, so that the valve closing speed is high enough; the actual opening area of the buffer holes 201 in the valve seating buffer period is stable and does not exceed the standard according to the pressure of the driven oil cavity 7, the seating time is shortest, the seating speed is less than or equal to 0.3m/s, and the number of the buffer holes 201 is the least, so that various requirements of the design of an engine valve mechanism are met. Compared with other schemes, the design of the check valve mainly takes the index of the initial opening stage of the valve as the main index, the design of the buffer hole 201 mainly takes the index of the rapid closing period and the seating buffer period of the valve as the main index, and the two designs are relatively independent, so that the electro-hydraulic CVVL mechanism is successfully applied to the engine with higher rotating speed.

when the cam lobe is acted upon by the lift, the cam lobe causes the drive plunger 4 to move upwardly. When the valve is in a closed state and the hydraulic valve 8 is opened, the driven plunger 1 is kept still due to the action of the valve spring force, namely the valve is kept in a closed state, the driving plunger 4 moves upwards, and hydraulic oil in the driving oil cavity 6 enters the energy accumulator 9 through the hydraulic valve 8. When the hydraulic valve 8 is closed, hydraulic oil in the driving oil cavity 6 firstly enters the driven oil cavity 7 through the one-way valve hole 13 and the one-way valve, the driven plunger 1 is pushed to overcome the spring force of the valve to move upwards, and the valve is opened, compared with a buffer scheme of the buffer table 101 or the buffer table 101 plus the buffer hole 201, the scheme has the advantages that the pressure difference between the driving oil cavity 6 and the driven oil cavity 7 is very small, namely, the pressure difference caused by the one-way valve is the pressure difference caused by the one-way valve, and the whole area of the driven plunger 1 plays a role, so the valve opening speed is very high, the fullness coefficient is high, the pressure of the driven oil cavity 7 is high, the cavitation phenomenon does not exist, and finally, the coupling influence caused; with the upward movement of the driven plunger 1, the actual opening area of the buffer hole 201 is gradually increased, the driving oil chamber 6 enters the driven oil chamber 7 through the one-way valve and the buffer hole 201, and the valve is continuously opened.

When the valve is in an open state and the hydraulic valve 8 is opened again under the action of the ascending section of the cam blade, the hydraulic oil in the driven oil cavity 7 flows out through the actually opened part of the buffer hole 201 under the action of the valve spring force and enters the energy accumulator 9 together with the hydraulic oil in the driving oil cavity 6 through the hydraulic valve 8. When the great lift of valve, hydraulic oil is great from the flow area when driven oil pocket 7 flows out, valve closing speed is great, along with the descending of driven plunger 1, after getting into the cushion chamber of taking a seat, cushion hole 201 is shielded gradually, this has resulted in driven oil pocket 7 pressure to increase, this plays the hindrance effect to driven plunger 1 and corresponding valve assembly's motion, the cushion scheme of buffer or buffer plus cushion hole, the whole area of driven plunger 1 bottom surface plays a role in this embodiment, therefore, the shared crankshaft angle of cushion period is taken a seat to the valve on the one hand can shorten, on the other hand, the pressure of driven oil pocket 7 can reduce, this has further improved fullness coefficient.

The drive plunger 4 spring causes the drive plunger 4 to move downwardly when the cam blade lowering segment is active. When the hydraulic valve 8 is closed, the driving plunger 4 moves downwards to cause the pressure of the driving oil cavity 6 to be reduced, hydraulic oil in the driven oil cavity 7 enters the driving oil cavity 6 through the buffer hole 201 under the action of the valve spring force, and the valve is gradually closed. When the hydraulic valve 8 is opened, under the action of the valve spring force, hydraulic oil in the driven oil cavity 7 flows out through the buffer hole 201, the valve is gradually closed, and the driven oil cavity 7, the driving oil cavity 6 and the energy accumulator 9 are communicated, so that the valve closing speed is higher than that when the hydraulic valve 8 is closed, and the valve closing timing is advanced. The process of achieving a drop cushion is similar to that described above and is not repeated. The method for controlling the valve operating parameters is the same as that adopted in the first embodiment, and is not described again.

In the fully-variable tappet cup, hydraulic oil in the driving oil cavity 6 at the initial stage of opening the valve acts on the whole area of the driven plunger 1 through the one-way valve, the opening speed of the valve is extremely high, so that the fullness coefficient is greatly improved, particularly, a larger valve lift at the initial stage of opening the valve is extremely favorable for the inflating efficiency of an engine, the pressure of the driving oil cavity 6 is greatly reduced, the pressure of the driven oil cavity 7 is greatly improved, and the driven oil cavity 7 is completely free from cavitation; in the valve seating buffer period, hydraulic oil acts on the whole area of the driven oil cavity 7, so that the pressure of the driven oil cavity 7 is greatly reduced, in addition, the buffer effect is only determined by the real-time area of the buffer hole 201, the coupling effect is much weaker than that of the previous scheme, especially, the strong coupling effect is not generated on the seating buffer period in the initial opening stage, the problems that the valve is rapidly opened and closed, the seating buffer is affected in the aspects of compact structure and the like in the previous scheme at high speed of the engine are solved, the design of the buffer table and the buffer hole can optimize the controllability, the consistency and the repeatability of the valve operation in a small amplitude, and the design of the one-way valve and the buffer hole can greatly optimize the controllability, the consistency and the repeatability; under the same maximum engine speed, the fullness coefficient is improved by more than 4-12%; the adaptive maximum rotating speed range of the engine is greatly improved by more than 20-35%.

EXAMPLE five

As shown in fig. 6, the structure, operation process, control method, etc. of the fully variable tappet cup of the present embodiment are the same as those of the fully variable tappet cup provided in the third embodiment, except that: in the fully variable tappet of the embodiment, a cavity is formed in one end, close to the buffer pedestal 202, of the driving plunger 4, corresponding to the return spring 5, the return spring 5 is inserted into the cavity, one end of the return spring 5 abuts against the plunger sleeve 2, and the other end of the return spring abuts against the driving plunger 4.

FIG. 7 is a comparison of valve lift curves for different schemes, where L is valve lift, and S1 is a valve lift curve for a scheme using check valves and cushion holes; s2 is a valve lift curve adopting a scheme of a buffer table and a buffer hole; s3 is the valve lift curve of the scheme only adopting the buffer platform; as can be seen from fig. 6, compared with the scheme only using the cushion table, the scheme using the cushion table and the cushion holes shortens the crank angle occupied by the valve in the initial opening stage and reduces the cushion stroke, which increases the rapid opening period and the rapid closing period of the valve and improves the fullness coefficient. In addition, further studies have shown that: under the same maximum engine speed, the fullness coefficient is improved by 2-5%; the pressure of the driving oil cavity 6 is reduced and the pressure of the driven oil cavity 7 is increased at the initial stage of opening the valve, and the pressure of the driven oil cavity 7 is reduced at the seating buffer stage; the maximum rotating speed range of the adaptive engine is improved by 4-9%. The change curve of the ideal buffer equivalent area along with the valve lift can be realized by reasonably arranging the buffer table 101 and the buffer holes 201 in the scheme of adding the buffer holes 201 to the buffer table 101. Compared with the scheme of adopting the buffer table and the buffer hole, the scheme of adopting the one-way valve and the buffer hole has the advantages that the valve opening speed at the initial stage of opening the valve is extremely high, the crank angle occupied by the valve seating buffer period is further shortened, the buffer stroke is further reduced, the crank angle occupied by the valve quick opening period and the valve quick closing period is greatly increased, the valve speed is also improved, the fullness coefficient is obviously increased, and particularly the larger valve lift at the initial stage of opening the valve is extremely favorable for the inflating efficiency of the engine. In addition, further studies have shown that: under the same maximum engine speed, the fullness coefficient is improved by more than 4-12%; at the initial stage of opening the valve, the pressure of the driving oil cavity 6 is greatly reduced, the pressure of the driven oil cavity 7 is greatly increased, and the driven oil cavity 7 is completely free from cavitation; in the valve seating buffer period, the pressure of the driven oil cavity 7 is greatly reduced; the adaptive maximum rotating speed range of the engine is greatly improved by more than 20-35%; the problems that the prior scheme takes account of the quick opening and closing of the valve, the seating buffer, the compact structure and the like at high speed of the engine are solved, and the controllability, the consistency and the repeatability of the valve operation are greatly improved. The main reason is that the hydraulic oil in the driving oil cavity 6 acts on the whole area of the driven plunger 1 through the one-way valve at the initial opening stage of the valve, the buffering effect is only determined by the real-time area of the buffering hole 201 at the valve seating buffering stage, and the hydraulic oil in the driven oil cavity 7 still acts on the whole area of the driven plunger 1, so that the problems of slow change of the valve operation speed, severe pressure fluctuation of the oil cavity and the like caused by the limited acting area of the hydraulic oil are solved, the coupling effect of the initial opening stage on the seating buffering stage is eliminated, and the self-coupling effect of the seating buffering stage is weakened.

Generally, the fully-variable tappet cup provided by the invention replaces a tappet cup in the original valve actuating mechanism, an engine body is not required to be changed, and the initial cost is close to 0; the number of parts of the valve actuating mechanism is very small, the processing cost is low, and the valve actuating mechanism is very favorable for popularization and application of products; variable valve events such as delayed opening, advanced closing, multiple opening and the like of the valve can be realized by controlling the opening and closing state of the hydraulic valve 8; through the flexible adjustment of the operating parameters of the valve and the improvement of the fullness coefficient, especially the scheme of the one-way valve and the buffer hole 201, the fullness coefficient is improved, the valve lift at the initial stage of opening of the valve is also improved, the fuel economy is finally improved by at least more than 2-4%, the in-cylinder discharge is reduced by more than 10-30%, the exhaust temperature is optimally managed, the exhaust temperature can be controlled within the temperature range of the working window of the aftertreatment catalyst under different engine working conditions, the working efficiency of the aftertreatment catalyst is effectively improved, and especially under the working conditions of warming up, low load and the like, the engine emission meets the latest emission regulations.

The principle and the implementation mode of the present invention are explained by applying specific examples in the present specification, and the above descriptions of the examples are only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.

Claims

1. The utility model provides a full changeable very cup which characterized in that: the oil cylinder comprises a fixed body, a driving plunger, a return spring and a driven plunger, wherein the driving plunger and the driven plunger are respectively in sliding fit with the fixed body; the driving oil cavity and the driven oil cavity are separated by a buffer pedestal fixedly connected with the fixed body, one end of the driven plunger close to the buffer pedestal is provided with a buffer table, the buffer pedestal is provided with a through hole corresponding to the buffer table, the buffer table can be inserted into the through hole, and the driving oil cavity is communicated with the driven oil cavity through the through hole; the fixing body is provided with a main oil hole, the driving oil cavity is communicated with the main oil hole through a plurality of fixing holes, the driven oil cavity is communicated with the main oil hole through a plurality of buffer holes, the main oil hole is communicated with the energy accumulator through an oil path, and the oil path is provided with a hydraulic valve; the return spring provides spring force to ensure that the mutual contact parts between the active plunger and the cam are always kept in contact.

2. The fully variable tappet cup according to claim 1, wherein: and the fixed body is also fixedly provided with a plunger sleeve, and the driving plunger and/or the driven plunger are/is in sliding fit with the plunger sleeve respectively.

3. The fully variable tappet cup according to claim 2, wherein: the buffer hole and/or the fixing hole are/is arranged on the plunger sleeve; the buffering pedestal and the plunger sleeve are integrally formed, and the driving oil cavity and/or the driven oil cavity are/is located in the plunger sleeve; an intermediate oil cavity is formed between the plunger sleeve and the fixing body, and the main oil hole, the buffer hole and the fixing hole are respectively communicated with the intermediate oil cavity.

4. The fully variable tappet cup according to claim 1, wherein: and a plurality of buffer grooves are arranged on the side wall surface of the buffer table or the buffer pedestal.

5. The utility model provides a full changeable very cup which characterized in that: the oil cylinder comprises a fixed body, a driving plunger, a return spring and a driven plunger, wherein the driving plunger and the driven plunger are respectively in sliding fit with the fixed body; the driving oil cavity is communicated with the driven oil cavity through a one-way valve hole, a one-way valve is arranged on the one-way valve hole, and hydraulic oil can only flow from the driving oil cavity to the driven oil cavity in a one-way mode through the one-way valve; the fixing body is provided with a main oil hole, the driving oil cavity is communicated with the main oil hole through a plurality of fixing holes, the driven oil cavity is communicated with the main oil hole through a plurality of buffer holes, the main oil hole is communicated with the energy accumulator through an oil path, and the oil path is provided with a hydraulic valve; the return spring provides spring force to ensure that the mutual contact parts between the active plunger and the cam are always kept in contact.

6. The fully variable tappet cup according to claim 5, wherein: and the fixed body is also fixedly provided with a plunger sleeve, and the driving plunger and/or the driven plunger are/is in sliding fit with the plunger sleeve respectively.

7. The fully variable tappet cup according to claim 6, wherein: the buffer hole and/or the fixing hole are/is arranged on the plunger sleeve; the one-way valve hole is formed in the plunger sleeve, and the driving oil cavity and/or the driven oil cavity are/is located in the plunger sleeve; an intermediate oil cavity is formed between the plunger sleeve and the fixing body, and the main oil hole, the buffer hole and the fixing hole are respectively communicated with the intermediate oil cavity.